Medical Surgical Nursing Case Study: Gastrointestinal System 1

A 37-year-old executive returns to your clinic for follow-up of recurrent upper abdominal pain. He initially presented 3 weeks ago, complaining of an increase in frequency and severity of burning epigastric pain, which he has experienced occasionally for more than 2 years. Now the pain occurs three or four times per
week, usually when he has an empty stomach, and it often awakens him at night. The pain usually is relieved within minutes by food or over-the-counter antacids, but then recurs within 2 to 3 hours. He admitted that stress at work had recently increased and that because of long working hours, he was drinking more caffeine
and eating a lot of take-out foods. His medical history and review of systems were otherwise unremarkable, and, other than the antacids, he takes no medications. His physical examination was normal, including stool guaiac that was negative for occult blood. You advised a change in diet and started him on a proton-pump
inhibitor. His symptoms resolved completely with the diet changes and daily use of the medication. Results of laboratory tests performed at his first visit show no anemia, but his serum Helicobacter pylori antibody test was positive.

What is your diagnosis?

What is your next step

Medical Surgical Nursing Case Study: Cardiovascular System 1

A 72-year-old man presents to the clinic complaining of several weeks of worsening exertional dyspnea. Previously, he had been able to work in his garden and mow the lawn, but now he feels short of breath after walking 100 feet. He does not have chest pain when he walks, although in the past he has experienced episodes of retrosternal chest pressure with strenuous exertion. Once recently he had felt lightheaded, as if he were about to faint while climbing a flight of stairs, but the symptom passed after he sat down. He has been having some difficulty sleeping at night and has to prop himself up with two pillows. Occasionally, he wakes up at night feeling quite short of breath, which is relieved within minutes by sitting upright and dangling his legs over the bed. His feet have become swollen, especially by the end of the day. He denies any significant medical history, takes no medications, and prides himself on the fact that he has not seen a doctor in years. He does not smoke or drink alcohol.

On physical examination, he is afebrile, with a heart rate of 86 bpm, blood pressure of 115/92 mm Hg, and respiratory rate of 16 breaths per minute. Examination of the head and neck reveals pink mucosa without pallor, a normal thyroid gland, and distended neck veins. Bibasilar inspiratory crackles are heard on examination. On cardiac examination, his heart rhythm is regular with a normal S1 and a second heart sound that splits during expiration, an S4 at the apex, a nondisplaced apical impulse, and a late-peaking systolic murmur at the right-upper sternal border that radiates to his carotids. The carotid upstrokes have diminished amplitude.

What is the most likely diagnosis?

What test would confirm the diagnosis?

Anatomy and Physiology Notes: Conduction System of the Heart

   Key Concepts

1. The electrical activity of cardiac cells is caused by the selective opening and closing of plasma membrane channels for sodium, potassium, and calcium ions.

2. Depolarization is achieved by the opening of sodium and calcium channels and the closing of potassium channels.

3. Repolarization is achieved by the opening of potassium channels and the closing of sodium and calcium

channels.

4. Pacemaker potentials are achieved by the opening of channels for sodium and calcium ions and the closing of channels for potassium ions.

5. Electrical activity is normally initiated in the sinoatrial (SA) node where pacemaker cells reach threshold first.

6. Electrical activity spreads across the atria, through the atrioventricular (AV) node, through the Purkinje system, and to ventricular muscle.

7. Norepinephrine increases pacemaker activity and the speed of action potential conduction.

8. Acetylcholine decreases pacemaker activity and the speed of action potential conduction.

9. Voltage differences between repolarized and depolarized regions of the heart are recorded by an electrocardiogram (ECG).

10. The ECG provides clinically useful information about rate, rhythm, pattern of depolarization, and mass of electrically active cardiac muscle.

Pathway

SA Node

|

Walls of the Atrium (Atrial Contraction)

|

AV Node

|

Delay in transmission

(To provide ample time for ventricular filling)

|

Bundle of His

|

Left and Right Bundle Branch

|

Purkinje Fibers

|

Ventricular Contraction

Anatomy and Physiology Notes: Gastrointestinal-Hepatobillary System

This is an outlined lecture note on the Anatomy and Physiology of theGastrointestinal-Hepatobillary System. Some information are so compressed that some concepts are not explained in detail. If it is your first time to meet such information please refer to your textbook for further explanation of the concept. This review material requires a student to have a prior knowledge and good foundation of the subject matter for this only emphasizes important/ key information deemed important in understanding advanced concept in Pathophysiology and Medical Surgical Nursing.

Functions of the gastrointestinal system
- Process food substances.
- Absorb the products of digestion into the blood.
- Excrete unabsorbed materials.
- Provide an environment for microorganisms to synthesize nutrients, such as vitamin K.

 Mouth
- Contains the lips, cheeks, palate, tongue, teeth, salivary glands, muscles, and maxillary bones
- Saliva contains the amylase enzyme (ptyalin) that aids in digestion.

Esophagus
- Collapsible muscular tube about 10 inches long
- Carries food from the pharynx to the stomach


The stomach
- Contains the cardia, fundus, the body, and the pylorus
- Mucous glands are located in the mucosa and prevent autodigestion by providing an alkaline protective covering.
- The lower esophageal (cardiac) sphincter prevents reflux of gastric contents into the esophagus.
- The pyloric sphincter regulates the rate of stomach emptying into the small intestine.
- Hydrochloric acid kills microorganisms, breaks food into small particles, and provides a chemical environment that facilitates gastric enzyme activation.
- Pepsin is the chief coenzyme of gastric juice, which converts proteins into proteases and peptones.
- Intrinsic factor is necessary for the absorption of vitamin B12.
- Gastrin controls gastric acidity.

Small intestine
- The duodenum contains the openings of the bile and pancreatic ducts.
- The jejunum is about 8 feet long.
- The ileum is about 12 feet long.
- The small intestine terminates in the cecum.

Pancreatic intestinal juice enzymes
- Amylase digests starch to maltose.
- Maltase reduces maltose to monosaccharide glucose.
-  Lactase splits lactose into galactose and glucose.
- Sucrase reduces sucrose to fructose and glucose.
- Nucleases split nucleic acids to nucleotides.
-. Enterokinase activates trypsinogen to trypsin.


Large intestine
- About 5 feet long
- Absorbs water and eliminates wastes
- Intestinal bacteria play a vital role in the synthesis of some B vitamins and vitamin K.
- Colon: Includes the ascending, transverse, descending, and sigmoid colons and rectum
- The ileocecal valve prevents contents of the large intestine from entering the ileum.
- The anal sphincters control the anal canal.

Peritoneum: Lines the abdominal cavity and forms the mesentery that supports
the intestines and blood supply

Liver
-The largest gland in the body, weighing 3 to 4 lb.
-Contains Kupffer's cells, which remove bacteria in the portal venous blood
- Removes excess glucose and amino acids from the portal blood
- Synthesizes glucose, amino acids, and fats
- Aids in the digestion of fats, carbohydrates, and proteins
- Stores and filters blood (200 to 400 mL of blood stored)
- Stores vitamins A, D, and B and iron
- The liver secretes bile to emulsify fats (500 to 1000 mL of bile/day).
 Hepatic ducts
a. Deliver bile to the gallbladder via the cystic duct and to the
duodenum via the common bile duct.
b. The common bile duct opens into the duodenum, with the pancreatic duct at the ampulla of Vater.
c. The sphincter prevents the reflux of intestinal contents into the
common bile duct and pancreatic duct.

Gallbladder
-Stores and concentrates bile and contracts to force bile into the duodenum during the digestion of fats
- The cystic duct joins the hepatic duct to form the common bile duct.
- The sphincter of Oddi is located at the entrance to the duodenum.
- The presence of fatty materials in the duodenum stimulates the liberation of cholecystokinin, which causes contraction of the gallbladder and relaxation of the sphincter of Oddi.

Pancreas
Exocrine gland
- Secretes sodium bicarbonate to neutralize the acidity of the stomach contents that enter the duodenum
-. Pancreatic juices contain enzymes for digesting carbohydrates, fats, and proteins.
Endocrine gland
- Secretes glucagon to raise blood glucose levels and secretes somatostatin to exert a hypoglycemic effect
- The islets of Langerhans secrete insulin.
- Insulin is secreted into the bloodstream and is important for carbohydrate metabolism.

“If at first you don't succeed, try, try again. Then quit. No use being a damn fool about it.”  -WC Fields

Anatomy and Physiology Notes: Endocrine System

This is an outlined lecture note on the Anatomy and Physiology of the Endocrine System. Some information are so compressed that some concepts are not explained in detail. If it is your first time to meet such information please refer to your textbook for further explanation of the concept. This review material requires a student to have a prior knowledge and good foundation of the subject matter for this only emphasizes important/ key information deemed important in understanding advanced concept in Pathophysiology and Medical Surgical Nursing.


Functions of Endocrine Glands
- Maintenance and regulation of vital functions
- Response to stress and injury
- Growth and development
- Energy metabolism
- Reproduction
- Fluid, electrolyte, and acid-base balance

Hypothalamus 
- Portion of the diencephalon of the brain, forming the floor and part of the lateral wall of the third ventricle
- Activates, controls, and integrates the peripheral autonomic nervous system, endocrine processes, and many somatic functions, such as body temperature, sleep, and appetite

Pituitary gland 
- The master gland; located at the base of the brain 2. Influenced by the hypothalamus; directly affects the function of the other endocrine glands
- Promotes growth of body tissue, influences water absorption by the kidney, and controls sexual development and function

Adrenal gland
- One adrenal gland is on top of each kidney.
- Regulates sodium and electrolyte balance; affects carbohydrate, fat, and protein metabolism; influences the development of sexual characteristics; and sustains the fight-or-flight response
 Adrenal cortex
- The cortex is the outer shell of the adrenal gland.
-. The cortex synthesizes glucocorticoids and mineralocorticoids and secretes small amounts of sex hormones
Adrenal medulla
- The medulla is the inner core of the adrenal gland.
- The medulla works as part of the sympathetic nervous system and produces epinephrine and norepinephrine.

Thyroid gland
- Located in the anterior part of the neck
- Controls the rate of body metabolism and growth and produces thyroxine (T4), triiodothyronine (T3), and thyrocalcitonin

Parathyroid glands
- Located on the thyroid gland
- Control calcium and phosphorus metabolism; produce parathyroid hormone

Pancreas
- Located posteriorly to the stomach
- Influences carbohydrate metabolism, indirectly influences fat and protein metabolism, and produces insulin and glucagon

Ovaries and testes
-The ovaries are located in the pelvic cavity and produce estrogen and progesterone.
-The testes are located in the scrotum, control the development of the secondary sex characteristics, and produce testosterone.

Negative feedback loop
-Regulates hormone secretion by the hypothalamus and pituitary gland
-Increased amounts of target gland hormones in the bloodstream decrease secretion of the same hormone and other hormones that stimulate its release.

“Success is getting what you want, happiness is wanting what you get” -Kinsela

Notes on Fluid and Electrolytes 3: FLUID VOLUME EXCESS

FLUID VOLUME EXCESS

A. Description
1. Fluid intake or fluid retention exceeds the fluid needs of the body.
2. Fluid volume excess also is called overhydration or fluid overload.
3. The goal of treatment is to restore fluid balance, correct electrolyte imbalances if present, and eliminate or control the underlying cause of the overload.

B. Types
1. Isotonic overhydration
a. Known as hypervolemia, isotonic overhydration results from excessive fluid in the extracellular fluid compartment.
b. Only the extracellular fluid compartment is expanded, and fluid does not shift between the extracellular and
intracellular compartments.
c. Isotonic overhydration causes circulatory overload and interstitial edema; when severe or when it occurs in a client with poor cardiac function, congestive heart
failure and pulmonary edema can result.

2. Hypertonic overhydration
a. Occurrence of hypertonic overhydration is rare and is caused by an excessive sodium intake.
b. Fluid is drawn from the intracellular fluid compartment; the extracellular fluid volume expands, and the intracellular fluid volume contracts.

3. Hypotonic overhydration
a. Hypotonic overhydration is known as water intoxication.
b. The excessive fluid moves into the intracellular space, and all body fluid compartments expand.
c. Electrolyte imbalances occur as a result of dilution.

C. Causes
1. Isotonic overhydration
a. Inadequately controlled IV therapy
b. Renal failure
c. Long-term corticosteroid therapy

2. Hypertonic overhydration
a. Excessive sodium ingestion
b. Rapid infusion of hypertonic saline
c. Excessive sodium bicarbonate therapy

3. Hypotonic overhydration
a. Early renal failure
b. Congestive heart failure
c. Syndrome of inappropriate antidiuretic hormone secretion
d. Inadequately controlled IV therapy
e. Replacement of isotonic fluid loss with hypotonic fluids
f. Irrigation of wounds and body cavities with hypotonic fluids

D. Assessment
1. Cardiovascular
a. Bounding, increased pulse rate
b. Elevated blood pressure
c. Distended neck and hand veins
d. Elevated central venous pressure

2. Respiratory
a. Increased respiratory rate (shallow respirations)
b. Dyspnea
c. Moist crackles on auscultation

3. Neuromuscular
a. Altered level of consciousness
b. Headache
c. Visual disturbances
d. Skeletal muscle weakness
e. Paresthesias

4. Integumentary
a. Pitting edema in dependent areas
b. Skin pale and cool to touch

5. Increased motility in the gastrointestinal tract

6. Isotonic overhydration results in liver enlargement and ascites.

7. Hypotonic overhydration results in the following:
a. Polyuria
b. Diarrhea
c. Nonpitting edema
d. Dysrhythmias
e. Projectile vomiting
8. Laboratory findings
a. Decreased serum osmolality
b. Decreased hematocrit
c. Decreased BUN level
d. Decreased serum sodium level
e. Decreased urine specific gravity

E. Interventions
1. Monitor cardiovascular, respiratory, neuromuscular, renal, integumentary, and gastrointestinal status.
2. Prevent further fluid overload, and restore normal fluid balance.
3. Administer diuretics; osmotic diuretics typically are prescribed first to prevent severe electrolyte imbalances.
4. Restrict fluid and sodium intake.
5. Monitor intake and output and weight.
6. Monitor electrolyte values, and prepare to administer medication to treat an imbalance if present.

Human Immunodeficiency Virus / Acquired immunodeficiency syndrome Lecture Notes

This is a Medical Surgical Nursing lecture note on AIDS/HIV in outlined format. Information and concepts are compressed to provide a quick review of the topic. Some information are so compressed that some concepts are not expounded in detail. If it is your first time to meet such information please refer to your textbook for further explanation of the concept. This review material requires a student to have a prior knowledge and good foundation of the subject matter for this only emphasizes important/ key information deemed important in understanding concepts in Pathophysiology and Medical Surgical Nursing.

Acquired immunodeficiency syndrome (AIDS)

•  AIDS is a viral disease caused by human immunodeficiency virus (HIV), which destroys T cells, thereby increasing susceptibility to infection and malignancy
•  The syndrome is manifested clinically by opportunistic infection and unusual neoplasms.
• AIDS is considered a chronic illness.
• The disease has a long incubation period, sometimes 10 years or longer.
• Manifestations may not appear until late in the infection.

High-risk groups
Heterosexual or homosexual contact with high-risk individuals
Intravenous drug abusers
Persons receiving blood products
Health care workers
Babies born to infected mothers

Assessment
Malaise, fever, anorexia, weight loss, influenza-like symptoms
Lymphadenopathy for at least 3 months
Leukopenia
Diarrhea
Fatigue
Night sweats
Presence of opportunistic infections
Protozoal infections (Pneumocystis jiroveci pneumonia, major source of mortality)
Neoplasms (Kaposi's sarcoma, purplish-red lesions of internal organs and skin, B-cell non-Hodgkin's lymphoma, cervical cancer)
Fungal infections (candidiasis, histoplasmosis)
Viral infections (cytomegalovirus, herpes simplex)
Bacterial infections

Interventions
1. Provide respiratory support.
2. Administer oxygen and respiratory treatments as prescribed.
3. Provide psychosocial support as needed.
4. Maintain fluid and electrolyte balance.
5. Monitor for signs of infection.
6. Prevent the spread of infection.
7. Initiate standard precautions.
8. Provide comfort as necessary.
9. Provide meticulous skin care.
10. Provide adequate nutritional support as prescribed.

"Success is not final, failure is not fatal: it is the courage to continue that counts"

Notes on Fluid and Electrolyte 2: CONCEPTS OF FLUID AND ELECTROLYTE BALANCE

CONCEPTS OF FLUID AND ELECTROLYTE BALANCE

Ebook Version here

A. Electrolytes
1. Description: A substance that is dissolved in solution and ome of its molecules split or dissociate into electrically charged atoms or ions.
2. Measurement
a. The metric system is used to measure volumes of fluids—liters (L) or milliliters (mL).
b. The unit of measure that expresses the combining activity of an electrolyte is the milliequivalent (mEq).
c. One milliequivalent (1 mEq) of any cation will always react chemically with 1 mEq of an anion.
d. Milliequivalents provide information about the number of anions or cations available to combine with other anions or cations.

B. Body fluid compartments

1. Description
a. Fluid in each of the body compartments contains electrolytes.
b. Each compartment has a particular composition of electrolytes, which differs from that of other compartments.
c. To function normally, body cells must have fluids and electrolytes in the right compartments and in the right amounts.
d. Whenever an electrolyte moves out of a cell, another electrolyte moves in to take its place.
e. The numbers of cations and anions must be the same for homeostasis to exist.
f. Compartments are separated by semipermeable membranes.

2. Intravascular compartment: Refers to fluid inside a blood vessel

3. Intracellular compartment
a. The intracellular compartment refers to all fluid inside the cell.
b. Most bodily fluids are inside the cell.

4. The extracellular compartment is the fluid outside the cell.
a. The extracellular compartment includes the interstitial fluid, which is fluid between cells (sometimes called the third space), blood, lymph, bone, connective tissue, water, and transcellular fluid.
b. Transcellular fluid is the fluid in various parts of the body, such as peritoneal fluid, pleural fluid, cerebrospinal fluid, and synovial fluid.

C. Third-spacing
1. Third-spacing is the accumulation and sequestration of trapped extracellular fluid in an actual or potential body space as a result of disease or injury.
2. The trapped fluid represents a volume loss and is unavailable for normal physiological processes.
3. Fluid may be trapped in body spaces such as the pericardial, pleural, peritoneal, or joint cavities, the bowel, or the aabdomen, or within soft tissues after trauma or burns.
4. Assessing the intravascular fluid loss caused by third-spacing is difficult. The loss may not be reflected
in weight changes or intake and output records and may not become apparent until after organ malfunction occurs.

D. Edema
1. Edema is an excess accumulation of fluid in the interstitial space.
2. Localized edema occurs as a result of traumatic injury from accidents or surgery, local inflammatory processes, or burns.
3. Generalized edema, also called anasarca, is an excessive accumulation of fluid in the interstitial space throughout the body and occurs as a result of conditions such as cardiac, renal, or liver failure.

E. Body fluid
1. Description
a. Body fluids transport nutrients to the cells and carry waste products from the cells.
b. Total body fluid (intracellular and extracellular) amounts to about 60% of body weight in the adult,
55% in the older adult, and 80% in the infant.
c. Thus, infants and the older adult are at ahigher risk for fluid-related problems than younger adults; children have a greater proportion of body water than adults and the older adult has the least proportion of body water.
2. Constituents of body fluids
a. Body fluids consist of water and dissolved substances.
b. The largest single fluid constituent of the body is water.
c. Some substances, such as glucose, urea, and creatinine, do not dissociate in solution; that is, they do not separate from their complex forms into simpler substances when they are in solution.
d. Other substances do dissociate; for example, when sodium chloride is in a solution, it dissociates or
separates into two parts or elements.

F. Body fluid transport
1. Diffusion
a. Diffusion is the process whereby a solute (substance that is dissolved) may spread through a solution or solvent (solution in which the solute is dissolved).
b. Diffusion of a solute will spread the molecules from an area of higher concentration to an area of lower concentration.
c. A permeable membrane will allow substances to pass through it without restriction.
d. A selectively permeable membrane will allow some solutes to pass through without restriction but will prevent other solutes from passing freely.
e. Diffusion occurs within fluid compartments and from one compartment to another if the barrier
between the compartments is permeable to the diffusing substances.

2. Osmosis
a. Osmotic pressure is the force that draws the solvent from a less concentrated solute through a selectively permeable membrane into a more concentrated solute, thus tending to equalize the concentration of the solvent.
b. If a membrane is permeable to water but not to all the solutes present, the membrane is a selective or semipermeable membrane.
c. Osmosis is the movement of solvent molecules across a membrane in response to a concentration gradient, usually from a solution of lower to one of higher solute concentration.
d. When a more concentrated solution is on one side of a selectively permeable membrane and a less concentrated solution is on the other side, a pull called osmotic pressure draws the water through
the membrane to the more concentrated side or the side with more solute.

3. Filtration
a. Filtration is the movement of solutes and solvents by hydrostatic pressure.
b. The movement is from an area of higher pressure to an area of lower pressure.

4. Hydrostatic pressure
a. Hydrostatic pressure is the force exerted by the weight of a solution.
b. When a difference exists in the hydrostatic pressure on two sides of a membrane, water and diffusible solutes move out of the solution that has the higher hydrostatic pressure by the process of filtration.
c. At the arterial end of the capillary, the hydrostatic pressure is higher than the osmotic pressure; therefore, fluids and diffusible solutes move out of the capillary.
d. At the venous end, the osmotic pressure or pull is higher than the hydrostatic pressure, and fluids and some solutes move into the capillary.
e. The excess fluid and solutes remaining in the interstitial spaces are returned to the intravascular compartment by the lymph channels.

5. Osmolality
a. Osmolality refers to the number of osmotically active particles/kilogram of water; it is the concentration of a solution.
b. In the body, osmotic pressure is measured in milliosmoles (mOsm).
c. The normal osmolality of plasma is 270 to 300 milliosmoles/kilogram (mOsm/kg) water.

G. Movement of body fluid
1. Description
a. Cell membranes separate the interstitial fluid from the intravascular fluid.
b. Cell membranes are selectively permeable; that is, the cell membrane and the capillary wall will allow water and some solutes free passage through them.
c. Several forces affect the movement of water and solutes through the walls of cells and capillaries.
d. The greater the number of particles within the cell, the more pressure exists to force the water through
the cell membrane.
e. If the body loses more electrolytes than fluids, as can happen in diarrhea, then the extracellular fluid will contain fewer electrolytes or less solute than the intracellular fluid.
f. Fluids and electrolytes must be kept in balance for health; when they remain out of balance, death can
occur.

2. Isotonic solutions
a. When the solutions on both sides of a selectively permeable membrane have established equilibrium or are equal in concentration, they are isotonic.
b. An example of an isotonic solution is 0.9% sodium chloride, which is referred to as isotonic saline solution or normal saline solution.
c. Isotonic solutions are isotonic to human cells, and thus very little osmosis occurs; isotonic solutions have the same osmolality as body fluids.
d. Other solutions that are isotonic are 5% dextrose in water, 5% dextrose in 0.225% saline, and Ringer's
lactate solution.

3. Hypotonic solutions
a. When a solution contains a lower concentration of salt or solute than another more concentrated solution, it is considered hypotonic.
b. A hypotonic solution has less salt or more water than an isotonic solution; these solutions have lower osmolality than body fluids.
c. 0.45% sodium chloride, 0.225% sodium chloride, and 0.33% sodium chloride are examples of hypotonic solutions.
d. Hypotonic solutions are hypotonic to the cells; therefore, osmosis would continue in an attempt to bring about balance or equality.

4. Hypertonic solutions
a. A solution that has a higher concentration of solutes than another less concentrated solution is hypertonic; these solutions have a higher osmolality than body fluids.
b. Hypertonic solutions include 3% sodium chloride, 5% sodium chloride, 10% dextrose in water, 5% dextrose in 0.9% sodium chloride, 5% dextrose in 0.45% sodium chloride, and 5% dextrose in Ringer's lactate solution.
c. Refer to Table 14-1 (Chap. 14) for a list of isotonic, hypotonic, and hypertonic solutions.

5. Osmotic pressure
a. The amount of osmotic pressure is determined by the concentration of solutes in solution.
b. When the solutions on each side of a selectively permeable membrane are equal in concentration, they are isotonic.
c. A hypotonic solution has less solute than an isotonic solution, whereas a hypertonic solution contains more solute.
d. A solvent will move from the less concentrated solute side to the more concentrated solute side to equalize concentration.

6. Active transport
a. If an ion is to move through a membrane from an area of lower concentration to an area of higher concentration, an active transport system is necessary.
b. An active transport system moves molecules or ions against concentration and osmotic pressure.
c. Metabolic processes in the cell supply the energy for active transport.
d. Substances that are transported actively through the cell membrane include ions of sodium, potassium, calcium, iron, and hydrogen, some of the sugars, and the amino acids.

H. Body fluid excretion
1. Description
a. Fluids leave the body by several routes, including the skin, lungs, gastrointestinal tract, and kidneys.
b. The kidneys excrete the largest quantity of fluid.
c. As long as all organs are functioning normally, the body is able to maintain balance in its fluid content.

2. Skin
a. Water is lost through the skin in the amount of about 400 mL/day.
b. The amount of water lost by perspiration varies according to the temperature of the environment and of the body, but the average amount of loss by perspiration alone is 100 mL/day.
c. Water lost through the skin is called insensible loss (the individual is unaware of losing that water).

3. Lungs
a. Water is lost from the lungs through expired air that is saturated with water vapor.
b. The amount of water lost from the lungs varies with the rate and the depth of respiration.
c. The average amount of water lost from the lungs is about 350 mL/day.
d. Water lost from the lungs is called insensible loss.

4. Gastrointestinal tract
a. Large quantities of water are secreted into the gastrointestinal tract, but almost all this fluid is reabsorbed.
b. A large volume of electrolyte-containing liquids moves into the gastrointestinal tract and then returns again into the extracellular fluid.
c. The average amount of water lost in the feces is 150 mL/day, equal to the amount of water gained through the oxidation of foods.
d. Severe diarrhea results in the loss of large quantities of fluids and electrolytes.

5. Kidneys
a. The kidneys play a major role in regulating fluid and electrolyte balance.
b. Normal kidneys can adjust the amount of water and electrolytes leaving the body.
c. The quantity of fluid excreted by the kidneys is determined by the amount of water ingested and the amount of waste and solutes excreted.
d. The usual urine output is about 1500 mL/day; however, this varies greatly depending on fluid intake, amount of perspiration, and other factors.

I. Body fluid replacement
1. Description: Water enters the body through three sources—orally ingested liquids, water in foods, and water formed by oxidation of foods.
2. Amounts
a. The average total amount of water taken into the body by all three sources is 2500 mL/day.
b. About 10 mL of water is released by the metabolism of each 100 calories of fat, carbohydrates, or proteins.
3. Electrolytes
a. Electrolytes are present in foods and liquids.
b. With a normal diet, an excess of essential electrolytes is
taken in and the unused electrolytes are excreted.

J. Maintaining fluid and electrolyte balance
1. Description
a. Homeostasis is a term that indicates the relative stability of the internal environment.
b. Concentration and composition of body fluids must be nearly constant.
c. In a client, when one of the substances is deficient, either fluids or electrolytes, the substance must be replaced normally by the intake of food and water or by therapy such as intravenous solutions and medications.
d. When the client has an excess of fluid or electrolytes, therapy is directed toward assisting the body to eliminate the excess.
2. The kidneys play a major role in controlling all types of balance in fluid and electrolytes.
3. The adrenal glands, through the secretion of aldosterone, also aid in controlling extracellular fluid volume by regulating the amount of sodium reabsorbed by the kidneys.
4. Antidiuretic hormone from the pituitary gland regulates the osmotic pressure of extracellular fluid by regulating the amount of water reabsorbed by the kidney.


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Notes on Fluids and Electrolytes Part 1

This Notes on Fluids and Electrolytes (1) focus primarily on the assessment of a fluid and electrolyte imbalance, interventions, and evaluating the expected outcomes. Fluids and electrolytes constitute a content area that is sometimes complex and difficult to understand. The nurse must understand cell functions and properties and the concepts related to body fluids as outlined in this chapter. It focuses on the common fluid and electrolyte disturbances. As you review this content, focus on the Pyramid Points related to the causes, assessment findings, and related treatments. In any fluid or electrolyte imbalance, nursing interventions include monitoring significant laboratory results and monitoring the client's cardiovascular, respiratory, gastrointestinal, neuromuscular, renal, and central nervous system status. Integrated Processes addressed in this chapter are Caring, Communication and Documentation, Nursing Process, and Teaching/Learning.

Important Terms

calcium
A mineral element needed for the process of bone formation, coagulation of blood, excitation of cardiac and skeletal muscle, maintenance of muscle tone, conduction of neuromuscular impulses, and the synthesis and regulation of the endocrine and exocrine glands. The normal adult level is 8.6 to 10.0 mg/dL.

fluid volume deficit
Dehydration in which the fluid intake of the body is not sufficient to meet the fluid needs of the body.

fluid volume excess
Fluid intake or fluid retention that exceeds the fluid needs of the body. Also called overhydration or fluid overload.

homeostasis
The tendency of biological systems to maintain relatively constant conditions in the internal environment while continuously interacting with and adjusting to changes originating within or outside the system.

hypercalcemia
A serum calcium level that exceeds 10.0 mg/dL.

hyperkalemia
A serum potassium level that exceeds 5.1 mEq/L.

hypermagnesemia
A serum magnesium level that exceeds 2.6 mg/dL.

hypernatremia
A serum sodium level that exceeds 145 mEq/L.

hyperphosphatemia
A serum phosphorus level that exceeds 4.5 mg/dL.

hypocalcemia
A serum calcium level less than 8.6 mg/dL.

hypokalemia
A serum potassium level less than 3.5 mEq/L.

hypomagnesemia
A serum magnesium level less than 1.6 mg/dL.

hyponatremia
A serum sodium level less than 135 mEq/L.

hypophosphatemia
A serum phosphorus level less than 2.7 mg/dL.

magnesium
Concentrated in the bone, cartilage, and within the cell itself; required for the use of adenosine triphosphate (ATP) as a source of energy. It is necessary for the action of numerous enzyme systems such as carbohydrate metabolism, protein synthesis, nucleic acid synthesis, and contraction of muscular tissue. It
also regulates neuromuscular activity and the clotting mechanism. The normal adult level is 1.6 to 2.6 mg/dL.

potassium
A principle electrolyte of intracellular fluid and the primary buffer within the cell itself. It is needed for nerve conduction, muscle function, acid-base balance, and osmotic pressure. Along with calcium and magnesium, it controls

sodium
An abundant electrolyte that maintains osmotic pressure and acid-base balance and transmits nerve impulses. The normal adult level is 135 to 145 mEq/L.

NCLEX-RN DRILL: MEDICAL SURGICAL CARDIOVASCULAR C

Medical Surgical Nursing is a very broad area in the field of Nursing for it tackles the management of different client condition. Books in Medical Surgical Nursing are usually divided according to the Organ System of the Human Body. The Cardiovascular System is one of the most difficult areas to study and to master since any deviation in this system will affect every organ system. Mastery is needed to be able to answer board type questions pertaining to Cardiovascualr System.



1. A client with no history of cardiovascular disease comes to the ambulatory clinic with flu-like symptoms. The client suddenly complains of chest pain. Which of the following questions would best help a nurse discriminate pain caused by a noncardiac problem?
1. “Can you describe the pain to me?”
2. “Have you ever had this pain before?”
3. “Does the pain get worse when you breathe in?”
4. “Can you rate the pain on a scale of 1 to 10, with 10 being the worst?”

2. A client is admitted to an emergency room with chest pain that is being ruled out for myocardial infarction. Vital signs are as follows: at 11 am, pulse (P), 92 beats/min, respiratory rate (RR), 24 breaths/min, blood pressure (BP), 140/88 mm Hg; 11:15 am, P, 96 beats/min, RR, 26 breaths/min, BP, 128/82 mm Hg; 11:30 am, P, 104 beats/min, RR, 28 breaths/min, BP, 104/68 mm Hg; 11:45 am, P, 118 beats/min, RR, 32 breaths/min, BP, 88/58 mm Hg. The nurse should alert the physician because these changes are most consistent with which of the following complications?
1. Cardiogenic shock
2. Cardiac tamponade
3. Pulmonary embolism
4. Dissecting thoracic aortic aneurysm

3. A client with myocardial infarction has been transferred from a coronary care unit to a general medical unit with cardiac monitoring via telemetry. A nurse plans to allow for which of the following client activities?
1. Strict bed rest for 24 hours after transfer
2. Bathroom privileges and self-care activities
3. Ad lib activities because the client is monitored
4. Unsupervised hallway ambulation with distances under 200 feet

4. A client admitted to the hospital with chest pain and history of type II diabetes mellitus is scheduled for cardiac catheterization. Which of the following medications would need to be held for 48 hours before and after the procedure?
1. Regular insulin
2. Glipizide (Glucotrol)
3. Repaglinide (Prandin)
4. Metformin (Glucophage)

5. A client is in sinus bradycardia with a heart rate of 45 beats/min, complains of dizziness, and has a blood pressure of 82/60 mmHg. Which of the following should the nurse anticipate will be prescribed?
1. Defibrillate the client.
2. Administer digoxin (Lanoxin).
3. Continue to monitor the client.
4. Prepare for transcutaneous pacing.

6. A nurse notes bilateral 12 edema in the lower extremities of a client with myocardial infarction who was admitted 2 days ago. The nurse would plan to do which of the following next?
1. Order daily weights starting on the following morning.
2. Review the intake and output records for the last 2 days.
3. Request a sodium restriction of 1 g/day from the physician
4. Change the time of diuretic administration from morning to evening.

7. A nurse is conducting a health history of a client with a primary diagnosis of heart failure. Which of the following disorders reported by the client is unlikely to play a role in exacerbating the heart failure?
1. Atrial fibrillation
2. Nutritional anemia
3. Peptic ulcer disease
4. Recent upper respiratory infection

8. A client with myocardial infarction suddenly becomes tachycardic, shows signs of air hunger, and begins coughing frothy, pink-tinged sputum. Which of the following would the nurse anticipate when auscultating the client's breath sounds?
1. Stridor
2. Crackles
3. Scattered rhonchi
4. Diminished breath sounds

9. A client who has developed severe pulmonary edema would most likely exhibit which of the following?
1. Mild anxiety
2. Slight anxiety
3. Extreme anxiety
4. Moderate anxiety

10. A client with pulmonary edema has been on diuretic therapy. The client has an order for additional furosemide (Lasix) in the amount of 40 mg intravenous push. Knowing that the client will also be started on digoxin (Lanoxin), the nurse should review which laboratory result?
1. Sodium level
2. Digoxin level
3. Creatinine level
4. Potassium level

NCLEX-RN DRILL: MEDICAL SURGICAL CARDIOVASCULAR B

Medical Surgical Nursing is a very broad area in the field of Nursing for it tackles the management of different client condition. Books in Medical Surgical Nursing are usually divided according to the Organ System of the Human Body. The Cardiovascular System is one of the most difficult areas to study and to master since any deviation in this system will affect every organ system. Mastery is needed to be able to answer board type questions pertaining to Cardiovascualr System.

1. The nurse realizes that more teaching is needed when the client on a cardiac low-cholesterol diet makes which choice from the menu?
a. Stewed chicken, green beans, and noodles
b. Liver and onions, salad with ranch dressing, and milk
c. Ham and bean soup, salad with vinaigrette dressing, and cornbread
d. Pork roast, brown rice, and beets

2. When taking a client’s medical history, which are the precipitating factors for myocardial infarction?
(Select all that apply.)
a. Hypothyroidism
b. Cigarette smoking
c. Hyperlipidemia
d. Rheumatic fever
e. Elevated serum iron level
f. High density lipids 40 mg
g. Using oral contraceptives

3. When the nurse performs an admission assessment on a client, the nurse notes that the client has xanthomas present on both eyelids. The laboratory value that the nurse would want to check based on this assessment finding is
a. triglyceride level
b. homocystine level
c. cardiac enzymes—CPK-MB, troponin, and myoglobin
d. cholesterol panel

4. A client presents to the clinic with the following symptoms: a burning sensation in the lower extremities, thickened toe nails, and pain in legs when walking. The nurse would assess the client for which additional factor consistent with Burger’s disease (thromboangitis obliterans)?
a. Bounding peripheral pulses
b. Rubor when the extremities are elevated
c. Intolerance to heat
d. Symptoms triggered by stress

5. A goal for a client with arteriosclerosis obliterans is to increase arterial blood supply to the extremities. Which of the following nursing interventions would be appropriate for this goal?
a. Elevate the extremities above the level of the heart for 15 minutes four times a day.
b. Have client perform Buerger-Allen exercises four times a day.
c. Maintain client on bed rest with legs in a neutral position.
d. Position client in high-Fowler’s position with legs straight.

6. Which of the following assessment findings are consistent with the diagnosis of venous stasis?
a. Absent or diminished peripheral pulses
b. Hair loss on the extremity
c. Moist ulcers around the malleolus
d. Edema of the extremity
e. Coolness of the extremity
f. Leathery quality of the extremity
g. Pallor of the extremity

7. A client is returned to the unit after having a repair of an abdominal aortic aneurysm. The nurse should place the client in which of the following positions?
a. High-Fowler’s
b. Sims
c. Semi-Fowler’s
d. Flat

8. The nurse is giving a client low molecular weight heparin, enoxaparin. The correct nursing interventions when administering this medication include all of the following except
a. using a TB syringe
b. injecting the medicine using Z-track method
c. not rubbing the site postinjection
d. administering the medicine in the anterolateral abdominal wall

9. In order to prevent the postoperative complication of thrombophlebitis in a client who has had mitral valve replacement, the nurse would have the client engage in which of the following activities?
a. Perform dorsiflexion of the feet several times every hour while awake
b. Cough and take deep breaths every hour while awake
c. Sit up in a chair for several hours during the afternoon
d. Eat a high-fiber, high-calorie diet

10. The nurse is caring for a client who has just arrived on the unit following a cardiac catheterization. Which of the following assessments would be most immediate?
a. Heart and lung sounds
b. Pain at the catheter insertion site
c. Pulses distal to the insertion site
d. Urine output

11. A client comes into the ER complaining of “his heart racing.” Cardiac monitor shows atrial tachycardia with a ventricular rate of 190 bpm. The nurse anticipates that the physician will order adenosine (Adenocard) to be given. Prior to giving the medication the nurse should do which of the following?
a. Determine when the client last ate
b. Ask the laboratory to draw serum BUN and creatinine levels
c. Ask the client if he/she has a history of asthma
d. Have the client sign a consent

12. Metoprolol tartrate (Lopressor) is ordered for a client who has had a myocardial infarction. The nurse would expect which therapeutic result from administration of this drug?
a. Increased urinary output
b. Decreased coronary artery spasms
c. Increased cardiac output
d. Decreased resting heart rate

13. A client’s cardiac monitor strip shows the following: HR 42/min, rhythm regular, PRI 0.16 seconds, QRS 0.06 seconds. The client is experiencing dizziness, nausea, and chest pain rated as 3 on a scale of 1–10 with 10 being the worst pain. The drug of choice to treat this dysrhythmia is
a. Lidocaine (Xylocaine)
b. Adenosine (Adenocard)
c. Atropine sulfate
d. Epinephrine (Adrenalin)

14. A client is admitted to the ER with new onset atrial fibrillation with a ventricular response of 110/min. The nurse would anticipate which of the following treatment options to be ordered. (Select all that apply.)
a. Defibrillation
b. Start oxygen at 2–4 lpm
c. Anticoagulant therapy
d. Medicate with beta blocker
e. Start Lidocaine drip
f. Atrial pacing

15. The nurse is assessing a newborn infant who is exhibiting the following signs and symptoms: elevated blood pressure, bounding brachial pulses, diminished pedal pulses, elevated Jugular venous distention (JVD), and cardiac murmur. Based on the assessment, the nurse would suspect that the client may have which of the following conditions?
a. Congestive heart failure
b. Coarctation of the aorta
c. Mitral valve prolapse
d. Transposition of the great vessels

16. The nurse has assessed a client and has determined that the client is exhibiting signs and symptoms of left heart failure. Identify which of the following are indicative of left heart failure.
a. Tachypnea, loss of appetite, ST elevation on the ECG
b. Hemoptysis, cogwheel murmur, midsternal chest pain
c. Ascites, oliguria, fatigue
d. Orthopnea, bibasilar crackles, gallop rhythm

17. The nurse is providing nutritional counseling for a client who is receiving a loop diuretic. Which meal plan would be most appropriate for this client?
a. Raisin bran cereal, tomato juice, whole grain toast
b. Boiled chicken, green beans, tossed salad
c. Vegetable soup, low-salt crackers, skim milk
d. Poached fish, beets, macaroni and cheese

18. The nurse is reading a 6-second cardiac rhythm strip and notes 9 QRS complexes in it. The client’s heart rate is
a. 54
b. 63
c. 81
d. 90

19. A client has been diagnosed with pericardial effusion. The nurse would prepare the client for which of the following procedures?
a. Myotomy
b. Pericardiectomy
c. Pericardiostomy
d. Dynamic cardiomyoplasty

20. Which instruction would be inappropriate to give a client following coronary artery bypass graft surgery?
a. No driving for 6–8 weeks
b. Avoid smoking or tobacco use for 4–6 weeks
c. No heavy lifting for 6–8 weeks
d. Can resume sexual intercourse in 3–4 weeks

NCLEX-RN DRILL: MEDICAL SURGICAL CARDIOVASCULAR A

Medical Surgical Nursing is a very broad area in the field of Nursing for it tackles the management of different client condition. Books in Medical Surgical Nursing are usually divided according to the Organ System of the Human Body. The Cardiovascular System is one of the most difficult areas to study and to master since any deviation in this system will affect every organ system. Mastery is needed to be able to answer board type questions pertaining to Cardiovascualr System.

1. A client with hypertension has an order for furosemide. Which lab finding should be reported to the physician?
A. Phosphorus 2.5 mEq/L
B. Potassium 1.8 mEq/L
C. Calcium 9.4 mg/dl
D. Magnesium 2.4 mEq/L

2. A client is admitted with a diagnosis of heart block. The nurse is aware that the pacemaker of the heart is the:
A. AV node
B. Purkinje fibers
C. SA node
D. Bundle of His

3. A client is being treated with nitroprusside (Nitropress). The nurse is aware that this medication:
A. Should be protected from light
B. Is a non–potassium-sparing diuretic
C. Causes vasoconstriction
D. Decreases circulation to the extremities

4. A client being treated with lisinopril (Zestril) develops a hacking cough. The nurse should tell the client to:
A. Take half the dose to control the problem
B. Take cough medication to control the problem
C. Stop the medication
D. Report the problem to the doctor

5. An elderly client taking digitalis develops constipation. The nurse is aware that constipation in a client taking digitalis might:
A. Develop an elevated digitalis level
B. Have a decrease in the digitalis levels
C. Have alterations in sodium levels
D. Develop tachycardia

6. The client is suspected of having had a myocardium infarction. Which diagnostic finding is most significant?
A. LDH
B. Troponin
C. Creatinine
D. AST

7. A client with an internally implanted defibrillator should be taught to:
A. Avoid driving a car
B. Avoid eating food cooked in a microwave
C. Refrain from using a cellular phone
D. Report swelling at the site

8. A client is scheduled for a cardiac catheterization. Following the procedure, the nurse should:
A. Assess for allergy to iodine
B. Check pulses proximal to the site
C. Assess the urinary output
D. Check to ensure that the client has a consent form signed

9. A client with Buerger’s disease complains of pain in the lower extremities. The nurse is aware that Buerger’s disease is also called:
A. Pheochromocytoma
B. Intermittent claudication
C. Kawasaki disease
D. Thromboangiitis obliterans

10. A client with an abdominal aneurysm frequently complains of:
A. A headache
B. Shortness of breath only during sleep
C. Lower back pain
D. Difficulty voiding

Health Assessment Lecture: Respiratory System D

Good assessment skill is paramount in providing quality nursing care. There is the reason why Assessment is the first step in the nursing process and is incorporated in every phase. In assessment nurses can gather pertinent information from the patient's health status so as to have a good overview of the patient's condition to be able to formulate a nursing diagnosis and even help doctors to come up with their medical diagnosis- much more it help the whole health care team.

Thoracic Percussion

Percussion sets the chest wall and underlying structures in motion, producing audible and tactile vibrations. The nurse uses percussion to determine whether underlying tissues are filled with air, fluid, or solid material. Percussion also is used to estimate the size and location of certain structures within the thorax (eg, diaphragm, heart, liver).

Percussion usually begins with the posterior thorax. Ideally, the patient is in a sitting position with the head flexed forward and the arms crossed on the lap. This position separates the scapulae widely and exposes more lung area for assessment. The nurse percusses across each shoulder top, locating the 5-cm width

of resonance overlying the lung apices. Then the nurse proceeds down the posterior thorax, percussing symmetric areas at 5- to 6-cm (2- to 2.5-inch) intervals. The middle finger is positioned parallel to the ribs in the intercostal space; the finger is placed firmly against the chest wall before striking it with the middle finger of the opposite hand. Bony structures (scapulae or ribs) are not percussed.

Percussion over the anterior chest is performed with the patient in an upright position with shoulders arched backward and arms at the side. The nurse begins in the supraclavicular area and proceeds downward, from one intercostal space to the next. In the female patient, it may be necessary to displace the breasts for an adequate examination. Dullness noted to the left of the sternum between the third and fifth intercostal spaces is a normal finding because it is the location of the heart. Similarly, there is a normal span of liver dullness in the right thorax from the fifth intercostal space to the right costal margin at the midclavicular line. The anterior and lateral thorax is examined with the patient in a supine position. If the patient cannot sit up, percussion of the posterior thorax is performed with the patient positioned on the side. Dullness over the lung occurs when air-filled lung tissue is replaced by fluid or solid tissue. 

DIAPHRAGMATIC EXCURSION

The normal resonance of the lung stops at the diaphragm. The position of the diaphragm is different during inspiration than during expiration. To assess the position and motion of the diaphragm, the nurse instructs the patient to take a deep breath and hold it while the maximal descent of the diaphragm is percussed. The point at which the percussion note at the midscapular line changes from resonance to dullness is marked with a pen. The patient is then instructed to exhale fully and hold it while the nurse again percusses downward to the dullness of the diaphragm. This point is also marked. The distance between the two markings indicates

the range of motion of the diaphragm. Maximal excursion of the diaphragm may be as much as 8 to 10 cm (3 to 4 inches) in healthy, tall young men, but for most people it is usually 5 to 7 cm (2 to 2.75 inches). 

Normally, the diaphragm is about 2 cm (0.75 inches) higher on the right because of the position of the heart and the liver above and below the left and right segments of the diaphragm, respectively. Decreased diaphragmatic excursion may occur with pleural effusion and emphysema. An increase in intra-abdominal pressure, as in pregnancy or ascites, may account for a diaphragm that is positioned high in the thorax.

Health Assessment Lecture: Respiratory System C

Good assessment skill is paramount in providing quality nursing care. There is the reason why Assessment is the first step in the nursing process and is incorporated in every phase. In assessment nurses can gather pertinent information from the patient's health status so as to have a good overview of the patient's condition to be able to formulate a nursing diagnosis and even help doctors to come up with their medical diagnosis- much more it help the whole health care team.

Thoracic Palpation

The nurse palpates the thorax for tenderness, masses, lesions, respiratory excursion, and vocal fremitus. If the patient has reported an area of pain or if lesions are apparent, the nurse performs direct palpation with the fingertips (for skin lesions and subcutaneous masses) or with the ball of the hand (for deeper masses or

generalized flank or rib discomfort).

RESPIRATORY EXCURSION

Respiratory excursion is an estimation of thoracic expansion and may disclose significant information about thoracic movement during breathing. The nurse assesses the patient for range and symmetry of excursion. The patient is instructed to inhale deeply while the movement of the nurse’s thumbs (placed along the costal margin on the anterior chest wall) during inspiration and expiration is observed. This movement is normally symmetric. 

Posterior assessment is performed by placing the thumbs adjacent to the spinal column at the level of the tenth rib. The hands lightly grasp the lateral rib cage. Sliding the thumbs medially about 2.5 cm (1 inch) raises a small skinfold between the thumbs. The patient is instructed to take a full inspiration and to exhale fully. The nurse observes for normal flattening of the skinfold and feels the symmetric movement of the thorax.

Decreased chest excursion may be due to chronic fibrotic disease. Asymmetric excursion may be due to splinting secondary to pleurisy, fractured ribs, trauma, or unilateral bronchial obstruction.

TACTILE FREMITUS

Sound generated by the larynx travels distally along the bronchial tree to set the chest wall in resonant motion. This is especially true of consonant sounds. The detection of the resulting vibration on the chest wall by touch is called tactile fremitus.

Normal fremitus is widely varied. It is influenced by the thickness of the chest wall, especially if that thickness is muscular. However, the increase in subcutaneous tissue associated with obesity may also affect fremitus. Lower-pitched sounds travel better through the normal lung and produce greater vibration of the chest wall. Thus, fremitus is more pronounced in men than in women because of the deeper male voice. 

Normally, fremitus is most pronounced where the large bronchi are closest to the chest wall and least palpable over the distant lung fields. Therefore, it is most palpable in the upper thorax, anteriorly and posteriorly. The patient is asked to repeat “ninety-nine” or “one, two, three,” or “eee, eee, eee” as the nurse’s hands move down the patient’s thorax. The vibrations are detected with the palmar surfaces of the fingers and hands, or the ulnar aspect of the extended hands, on the thorax. The hand or hands are moved in sequence down the thorax. Corresponding areas of the thorax are compared . Bony areas are not tested.

Air does not conduct sound well but a solid substance such as tissue does, provided that it has elasticity and is not compressed. Thus, an increase in solid tissue per unit volume of lung will enhance fremitus; an increase in air per unit volume of lung will impede sound. Patients with emphysema, which results in the rupture of alveoli and trapping of air, exhibit almost no tactile fremitus. A patient with consolidation of a lobe of the lung from pneumonia will have increased tactile fremitus over that lobe. Air in the pleural space will not conduct sound.

Health Assessment Lecture: Respiratory System B

Good assessment skill is paramount in providing quality nursing care. There is the reason why Assessment is the first step in the nursing process and is incorporated in every phase. In assessment nurses can gather pertinent information from the patient's health status so as to have a good overview of the patient's condition to be able to formulate a nursing diagnosis and even help doctors to come up with their medical diagnosis- much more it help the whole health care team.

PHYSICAL ASSESSMENT OF THE LOWER RESPIRATORY STRUCTURES AND BREATHING

Thorax

Inspection of the thorax provides information about the musculoskeletal structure, the patient’s nutritional status, and the respiratory system. The nurse observes the skin over the thorax for color and turgor and for evidence of loss of subcutaneous tissue. It is important to note asymmetry, if present. When findings are

recorded or reported, anatomic landmarks are used as points of reference

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CHEST CONFIGURATION

Normally, the ratio of the anteroposterior diameter to the lateral diameter is 1 2. However, there are four main deformities of the chest associated with respiratory disease that alter this relationship: barrel chest, funnel chest (pectus excavatum), pigeon chest (pectus carinatum), and kyphoscoliosis.

Barrel Chest. Barrel chest occurs as a result of overinflation of the lungs. There is an increase in the anteroposterior diameter of the thorax. In a patient with emphysema, the ribs are more widely spaced and the intercostal spaces tend to bulge on expiration. The appearance of the patient with advanced emphysema is thus quite characteristic and often allows the observer to detect its presence easily, even from a distance.

Funnel Chest (Pectus Excavatum). Funnel chest occurs when there is a depression in the lower portion of the sternum. This may compress the heart and great vessels, resulting in murmurs. Funnel chest may occur with rickets or Marfan’s syndrome.

Pigeon Chest (Pectus Carinatum). A pigeon chest occurs as a result of displacement of the sternum. There is an increase in the anteroposterior diameter. This may occur with rickets, Marfan’s syndrome, or severe kyphoscoliosis.

Kyphoscoliosis. A kyphoscoliosis is characterized by elevation of the scapula and a corresponding S-shaped spine. This deformity limits lung expansion within the thorax. It may occur with osteoporosis and other skeletal disorders that affect the thorax.

BREATHING PATTERNS AND RESPIRATORY RATES

Observing the rate and depth of respiration is a simple but important aspect of assessment. The normal adult who is resting comfortably takes 12 to 18 breaths per minute. Except for occasional sighs, respirations are regular in depth and rhythm. This normal pattern is described as eupnea. 

Bradypnea, also called slow breathing, is associated with increased intracranial pressure, brain injury, and drug overdose. Tachypnea, or rapid breathing, is commonly seen in patients with pneumonia, pulmonary edema, metabolic acidosis, septicemia, severe pain, and rib fracture.  Shallow, irregular breathing is referred to as hypoventilation. An increase in depth of respirations is called hyperpnea. 

An increase in both rate and depth that results in a lowered arterial PCO2 level is referred to as hyperventilation. With rapid breathing, inspiration and expiration are nearly equal in duration. Hyperventilation that is marked by an increase in rate and depth, associated with severe acidosis of diabetic or renal origin, is called Kussmaul’s respiration.

Apnea describes varying periods of cessation of breathing. If sustained, apnea is life-threatening.

Cheyne-Stokes respiration is characterized by alternating episodes of apnea (cessation of breathing) and periods of deep breathing. Deep respirations become increasingly shallow, followed by apnea that may last approximately 20 seconds. The cycle repeats after each apneic period. The duration of the period of apnea may vary and may progressively lengthen; therefore, it is timed and reported. Cheyne-Stokes respiration is usually associated with heart failure and damage to the respiratory center (drug-induced, tumor, trauma).

Biot’s respirations, or cluster breathing, are cycles of breaths that vary in depth and have varying periods of apnea. Biot’s respirations are seen with some central nervous system disorders.

Certain patterns of respiration are characteristic of specific disease states. Respiratory rhythms and their deviation from normal are important observations that the nurse reports and documents. The rate and depth of different patterns of respiration are presented

In thin people, it is quite normal to note a slight retraction of the intercostal spaces during quiet breathing. Bulging during expiration implies obstruction of expiratory airflow, as in emphysema. Marked retraction on inspiration, particularly if asymmetric, implies blockage of a branch of the respiratory tree. Asymmetric bulging of the intercostal spaces, on one side or the other, is created by an increase in pressure within the hemithorax. This may be a result of air trapped under pressure within the pleural cavity where it does not normally appear (pneumothorax) or the pressure of fluid within the pleural space (pleural effusion).

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Health Assessment Lecture: Respiratory System A

Good assessment skill is paramount in providing quality nursing care. There is the reason why Assessment is the first step in the nursing process and is incorporated in every phase. In assessment nurses can gather pertinent information from the patient's health status so as to have a good overview of the patient's condition to be able to formulate a nursing diagnosis and even help doctors to come up with their medical diagnosis- much more it help the whole health care team.

The health history focuses on the physical and functional problems of the patient and the effect of these problems on his or her life. The reason the patient is seeking health care often is related to one of the following: dyspnea (shortness of breath), pain, accumulation of mucus, wheezing, hemoptysis (blood spit up from the respiratory tract), edema of the ankles and feet, cough, and general fatigue and weakness.

In addition to identifying the chief reason why the patient is seeking health care, the nurse tries to determine when the health problem or symptom started, how long it lasted, if it was relieved at any time, and how relief was obtained. The nurse collects information about precipitating factors, duration, severity, and associated

factors or symptoms and also assesses for risk factors and genetic factors that may contribute to the patient’s lung condition.

The nurse assesses the impact of signs and symptoms on the patient’s ability to perform activities of daily living and to participate in usual work and family activities. In addition, psychosocial factors that may affect the patient are explored. These factors include anxiety, role changes, family relationships, financial problems, employment status, and the strategies the patient uses to cope with them.

Many respiratory diseases are chronic and progressively debilitating. Therefore, ongoing assessment of the patient’s physical abilities, psychosocial supports, and quality of life is needed to plan appropriate interventions. It is important for the patient with a respiratory disorder to understand the condition and to be

familiar with necessary self-care interventions. The nurse evaluates these factors over time and provides education as needed.

Signs and Symptoms

The major signs and symptoms of respiratory disease are dyspnea, cough, sputum production, chest pain, wheezing, clubbing of the fingers, hemoptysis, and cyanosis. These clinical manifestations are related to the duration and severity of the disease.

DYSPNEA

Dyspnea (difficult or labored breathing, shortness of breath) is a symptom common to many pulmonary and cardiac disorders, particularly when there is decreased lung compliance or increased airway resistance. The right ventricle of the heart will be affected ultimately by lung disease because it must pump blood through

the lungs against greater resistance. It may also be associated with neurologic or neuromuscular disorders such as myasthenia gravis, Guillain-Barré syndrome, or muscular dystrophy.

Clinical Significance. In general, acute diseases of the lungs produce a more severe grade of dyspnea than do chronic diseases. Sudden dyspnea in a healthy person may indicate pneumothorax (air in the pleural cavity), acute respiratory obstruction, or ARDS. In immobilized patients, sudden dyspnea may denote pulmonary embolism. Orthopnea (inability to breathe easily except in an upright position) may be found in patients with heart disease and occasionally in patients with chronic obstructive pulmonary disease (COPD); dyspnea with an expiratory wheeze occurs with COPD. Noisy breathing may result from a narrowing of the airway or localized obstruction of a major bronchus by a tumor or foreign body. The presence of both inspiratory and expiratory wheezing usually signifies asthma if the patient does not have heart failure.

The circumstance that produces the dyspnea must be determined. Therefore, it is important to ask the patient the following questions:

• How much exertion triggers shortness of breath?

• Is there an associated cough?

• Is dyspnea related to other symptoms?

• Was the onset of shortness of breath sudden or gradual?

• At what time of day or night does the dyspnea occur?

• Is the shortness of breath worse when the patient is flat in bed?

• Does the shortness of breath occur at rest? With exercise? Running? Climbing stairs?

• Is the shortness of breath worse while walking? If so, when walking how far? How fast?

Relief Measures. The management of dyspnea is aimed at identifying and correcting its cause. Relief of the symptom sometimes is achieved by placing the patient at rest with the head elevated (high Fowler’s position) and, in severe cases, by administering oxygen.

COUGH

Cough results from irritation of the mucous membranes anywhere in the respiratory tract. The stimulus producing a cough may arise from an infectious process or from an airborne irritant, such as smoke, smog, dust, or a gas. The cough is the patient’s chief protection against the accumulation of secretions in the bronchi and bronchioles.

Clinical Significance. Cough may indicate serious pulmonary disease. The nurse needs to evaluate the character of the cough is it dry, hacking, brassy, wheezing, loose, or severe? A dry, irritative cough is characteristic of an upper respiratory tract infection of viral origin or may be a side effect of angiotensin-converting enzyme (ACE) inhibitor therapy. Laryngotracheitis causes an irritative, high-pitched cough. Tracheal lesions produce a brassy cough. A severe or changing cough may indicate bronchogenic carcinoma. Pleuritic chest pain accompanying coughing may indicate pleural or chest wall (musculoskeletal) involvement

The time of coughing is also noted. Coughing at night may herald the onset of left-sided heart failure or bronchial asthma. A cough in the morning with sputum production may indicate bronchitis. A cough that worsens when the patient is supine suggests postnasal drip (sinusitis). Coughing after food intake may

indicate aspiration of material into the tracheobronchial tree. A cough of recent onset is usually from an acute infection.

SPUTUM PRODUCTION

A patient who coughs long enough almost invariably produces sputum. Violent coughing causes bronchial spasm, obstruction, and further irritation of the bronchi and may result in syncope (fainting). A severe, repeated, or uncontrolled cough that is nonproductive is exhausting and potentially harmful. Sputum production is the reaction of the lungs to any constantly recurring irritant. It also may be associated with a nasal discharge.

Clinical Significance. A profuse amount of purulent sputum (thick and yellow, green, or rust-colored) or a change in color of the sputum probably indicates a bacterial infection. Thin, mucoid sputum frequently results from viral bronchitis. A gradual increase of sputum over time may indicate the presence of chronic bronchitis or bronchiectasis. Pink-tinged mucoid sputum suggests a lung tumor. Profuse, frothy, pink material, often welling up into the throat, may indicate pulmonary edema. Foul-smelling sputum and bad breath point to the presence of a lung abscess, bronchiectasis, or an infection caused by fusospirochetal or other anaerobic organisms.

Relief Measures. If the sputum is too thick for the patient to expectorate, it is necessary to decrease its viscosity by increasing its water content through adequate hydration (drinking water) and inhalation of aerosolized solutions, which may be delivered by any type of nebulizer. Strategies to assist the patient to cough productively are discussed later in this chapter.

Smoking is contraindicated with excessive sputum production because it interferes with ciliary action, increases bronchial secretions, causes inflammation and hyperplasia of the mucous membranes, and reduces production of surfactant. Thus, smoking impairs bronchial drainage. When the person stops smoking,

sputum volume decreases and resistance to bronchial infections increases.

The patient’s appetite may decrease because of the odor of the sputum or the taste it leaves in the mouth. The nurse encourages adequate oral hygiene and wise selection of food, measures that will stimulate appetite. In addition, the nurse encourages the patient and family to remove sputum cups, emesis basins, and soiled

tissues before mealtime. Encouraging the patient to drink citrus juices at the beginning of the meal may increase the palatability of the rest of the meal because these juices cleanse the palate of the sputum taste.

CHEST PAIN

Chest pain or discomfort may be associated with pulmonary or cardiac disease. Chest pain associated with pulmonary conditions may be sharp, stabbing, and intermittent, or it may be dull, aching, and persistent. The pain usually is felt on the side where the pathologic process is located, but it may be referred elsewhere—for example, to the neck, back, or abdomen.

Clinical Significance. Chest pain may occur with pneumonia, pulmonary embolism with lung infarction, and pleurisy. It also may be a late symptom of bronchogenic carcinoma. In carcinoma the pain may be dull and persistent because the cancer has invaded the chest wall, mediastinum, or spine.

Lung disease does not always produce thoracic pain because the lungs and the visceral pleura lack sensory nerves and are insensitive to pain stimuli. However, the parietal pleura has a rich supply of sensory nerves that are stimulated by inflammation and stretching of the membrane. Pleuritic pain from irritation of the parietal pleura is sharp and seems to “catch” on inspiration; patients often describe it as “like the stabbing of a knife.” Patients are more comfortable when they lie on the affected side as this splints the chest wall, limits expansion and contraction of the lung, and reduces the friction between the injured or diseased pleurae on that side. Pain associated with cough may be reduced manually by splinting the rib cage.

The nurse assesses the quality, intensity, and radiation of pain and identifies and explores precipitating factors, along with their relationship to the patient’s position. Also, it is important to assess the relationship of pain to the inspiratory and expiratory phases of respiration.

Relief Measures. Analgesic medications may be effective in relieving chest pain, but care must be taken not to depress the respiratory center or a productive cough, if present. Nonsteroidal anti-inflammatory drugs (NSAIDs) achieve this goal and thus are used for pleuritic pain. A regional anesthetic block may be performed to relieve extreme pain.

WHEEZING

Wheezing is often the major finding in a patient with bronchoconstriction or airway narrowing. It is heard with or without a stethoscope, depending on its location. Wheezing is a highpitched, musical sound heard mainly on expiration. 

Relief Measures. Oral or inhalant bronchodilator medications reverse wheezing in most instances.

CLUBBING OF THE FINGERS

Clubbing of the fingers is a sign of lung disease found in patients with chronic hypoxic conditions, chronic lung infections, and malignancies of the lung. This finding may be manifested initially as sponginess of the nailbed and loss of the nailbed angle.

HEMOPTYSIS

Hemoptysis (expectoration of blood from the respiratory tract) is a symptom of both pulmonary and cardiac disorders. The onset of hemoptysis is usually sudden, and it may be intermittent or continuous. Signs, which vary from blood-stained sputum to a large, sudden hemorrhage, always merit investigation. The most common causes are:

• Pulmonary infection

• Carcinoma of the lung

• Abnormalities of the heart or blood vessels

• Pulmonary artery or vein abnormalities

• Pulmonary emboli and infarction

Diagnostic evaluation to determine the cause includes several studies: chest x-ray, chest angiography, and bronchoscopy. A careful history and physical examination are necessary to diagnose the underlying disease, irrespective of whether the bleeding involved a very small amount of blood in the sputum or a massive hemorrhage.

The amount of blood produced is not always proportional to the seriousness of the cause.

First, it is important to determine the source of the bleeding— the gums, nasopharynx, lungs, or stomach. The nurse may be the only witness to the episode. When documenting the bleeding episode, the nurse considers the following points:

• Bloody sputum from the nose or the nasopharynx is usually preceded by considerable sniffing, with blood possibly appearing in the nose.

• Blood from the lung is usually bright red, frothy, and mixed with sputum. Initial symptoms include a tickling sensation in the throat, a salty taste, a burning or bubbling sensation in the chest, and perhaps chest pain, in which case the patient tends to splint the bleeding side. The term “hemoptysis” is reserved for the coughing up of blood arising from a pulmonary hemorrhage. This blood has an alkaline pH (greater than 7.0).

• If the hemorrhage is in the stomach, the blood is vomited (hematemesis) rather than coughed up. Blood that has been in contact with gastric juice is sometimes so dark that it is referred to as “coffee grounds.” This blood has an acid pH (less than 7.0).

CYANOSIS

Cyanosis, a bluish coloring of the skin, is a very late indicator of hypoxia. The presence or absence of cyanosis is determined by the amount of unoxygenated hemoglobin in the blood. Cyanosis appears when there is 5 g/dL of unoxygenated hemoglobin. A patient with a hemoglobin level of 15 g/dL will not demonstrate cyanosis until 5 g/dL of that hemoglobin becomes unoxygenated, reducing the effective circulating hemoglobin to two thirds of the normal level. An anemic patient rarely manifests cyanosis, and a

polycythemic patient may appear cyanotic even if adequately oxygenated. Therefore, cyanosis is not a reliable sign of hypoxia. Assessment of cyanosis is affected by room lighting, the patient’s skin color, and the distance of the blood vessels from the surface of the skin. In the presence of a pulmonary condition, central cyanosis is assessed by observing the color of the tongue and lips. This indicates a decrease in oxygen tension in the blood. Peripheral cyanosis results from decreased blood flow to a certain area of the body, as in vasoconstriction of the nailbeds or earlobes from exposure to cold, and does not necessarily indicate a central systemic problem.

A&P Lecture 4: Sturcture Respiratory System

NOTE: The following organ lecture on Anatomy and Physiology will be structured closely to concepts by which nurses must know to be able to have a good foundation in the normal Anatomy and Physiology to know the normal from abnormal findings for Health Assessment and to have a good grasp regarding deviations in the normal functions and structures of the the body in contrast to that during an illness state for advance subjects such as Medical-Surgical Nursing, Maternal and Child Nursing and Psychiatric Nursing.

ANATOMY AND PHYSIOLOGY LECTURE 4

RESPIRATORY SYSTEM

Nurses often encounter disorders of the respiratory system from the community to the intensive care unit. The diversity of respiratory ailments from simple colds to an evolving pulmonary edema necessitates an the development of expert assessment  skills to provide accurate problem identification and prompt treatment to be able to return patients in their optimal level of functioning. In order to differentiate between normal and abnormal assessment findings, an understanding of respiratory function and the significance of abnormal diagnostic test results is essential.

Overview

The respiratory system is composed of the upper and lower respiratory tracts. Together, the two tracts are responsible for ventilation. The upper respiratory tract warms and filters inspired air so that the lower respiratory tract can accomplish gas exchange. Gas exchange involves delivering oxygen to the tissues through the bloodstream and expelling waste gases, such as carbon dioxide, during expiration. The respiratory system works with the cardiovascular system; the respiratory system is responsible for ventilation and diffusion, and the cardiovascular system is responsible for oxygen delivery. 

Upper Respiratory Tract

Nose

Our nose serves as a passageway for air to pass to and from the lungs. It filters impurities and humidifies and warms the air as it is inhaled. The nose is composed of an external and an internal portion. The external portion protrudes from the face and is supported by the nasal bones and cartilage. The anterior nares (nostrils) are the external openings of the nasal cavities.

The internal portion of the nose is a hollow cavity separated into the right and left nasal cavities by a narrow vertical divider, the septum. Each nasal cavity is divided into three passageways by the projection of the turbinates from the lateral walls. The turbinate bones are also called conchae for the name suggested by their shell-like appearance. Because of their curves, these bones increase the mucous membrane surface

of the nasal passages and slightly obstruct the air flowing

through them.

Air entering the nostrils is deflected upward to the roof of the nose, and it follows a circuitous route before it

reaches the nasopharynx. It comes into contact with a large surface of moist, warm, highly vascular, ciliated mucous membrane (called nasal mucosa) that traps practically all the dust and organisms in the inhaled air. The air is moistened, warmed to body temperature, and brought into contact with sensitive nerves. Some of these nerves detect odors; others provoke sneezing to expel irritating dust. Mucus, secreted continuously by goblet cells, covers the surface of the nasal mucosa and is moved back to the nasopharynx by the action of the cilia which are fine hairs.

Paranasal Sinuses

The paranasal sinuses include four pairs of bony cavities that are lined with nasal mucosa and ciliated pseudostratified columnar epithelium. These air spaces are connected by a series of ducts that drain into the nasal cavity. The sinuses are named by their location: frontal, ethmoidal, sphenoidal, and maxillary . A prominent function of the sinuses is to serve as a resonating chamber in speech. The sinuses are a common site of infection.

Pharynx, Tonsils, and Adenoids

The pharynx, or throat, is a tubelike structure that connects the nasal and oral cavities to the larynx. It is divided into three regions: nasal, oral, and laryngeal. The nasopharynx is located posterior to the nose and above the soft palate. The oropharynx houses the faucial, or palatine, tonsils. The laryngopharynx extends from the hyoid bone to the cricoid cartilage. The epiglottis forms the entrance to the larynx. The adenoids, or pharyngeal tonsils, are located in the roof of the nasopharynx. The tonsils, the adenoids, and other lymphoid tissue encircle the throat. These structures are important links in the chain of lymph nodes guarding the body from invasion by organisms entering the nose and the throat. The pharynx functions as a passageway for the respiratory and digestive tracts.

Larynx

The larynx, or voice organ, is a cartilaginous epitheliumlined structure that connects the pharynx and the trachea. The major function of the larynx is vocalization. It also protects the lower airway from foreign substances and facilitates coughing. It is frequently referred to as the voice box and consists of the following:

• Epiglottis: a valve flap of cartilage that covers the opening to the larynx during swallowing

• Glottis: the opening between the vocal cords in the larynx

• Thyroid cartilage: the largest of the cartilage structures; part of it forms the Adam’s apple

• Cricoid cartilage: the only complete cartilaginous ring in the larynx (located below the thyroid cartilage)

• Arytenoid cartilages: used in vocal cord movement with the thyroid cartilage

• Vocal cords: ligaments controlled by muscular movements that produce sounds; located in the lumen of

the larynx. 

Trachea

The trachea, or windpipe, is composed of smooth muscle with C-shaped rings of cartilage at regular intervals. The cartilaginous rings are incomplete on the posterior surface and give firmness to the wall of the trachea, preventing it from collapsing. The trachea serves as the passage between the larynx and the bronchi

Lower Respiratory Tract

The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange.

Lungs

The lungs are paired elastic structures enclosed in the thoracic cage, which is an airtight chamber with distensible walls. Ventilation requires movement of the walls of the thoracic cage and of its floor, the diaphragm. The effect of these movements is alternately to increase and decrease the capacity of the chest. When the capacity of the chest is increased, air enters through the trachea (inspiration) because of the lowered pressure within and inflates the lungs. When the chest wall and diaphragm return to their previous positions (expiration), the lungs recoil and force the air out through the bronchi and trachea. Inspiration occurs during the first third of the respiratory cycle, expiration during the later two thirds. The inspiratory phase of respiration normally requires energy; the expiratory phase is normally passive, requiring very little energy. In respiratory diseases, such as chronic obstructive pulmonary disease (COPD), expiration requires energy.

Pleura

The lungs and wall of the thorax are lined with a serous membrane called the pleura. The visceral pleura covers the lungs; the parietal pleura lines the thorax. The visceral and parietal pleura and the small amount of pleural fluid between these two membranes serve to lubricate the thorax and lungs and permit smooth motion of the lungs within the thoracic cavity with each breath.

Mediastinum

The mediastinum is in the middle of the thorax, between the pleural sacs that contain the two lungs. It extends from the sternum to the vertebral column and contains all the thoracic tissue outside the lungs (heart, thymus,

certain large blood vessels [ie, aorta, vena cava], and esophagus).

Lobes

Each lung is divided into lobes. The right lung has upper, middle, and lower lobes, whereas the left lung consists of upper and lower lobes. Each lobe is further subdivided into two to five segments separated by fissures, which are extensions of the pleura.

Bronchi and Bronchioles

There are several divisions of the bronchi within each lobe of the lung. First are the lobar bronchi (three in the right lung and two in the left lung). Lobar bronchi divide into segmental bronchi (10 on the right and 8 on the left), which are the structures identified when choosing the most effective postural drainage position for a given patient. Segmental bronchi then divide into subsegmental bronchi. These bronchi are surrounded by connective tissue that contains arteries, lymphatics, and nerves.

The subsegmental bronchi then branch into bronchioles, which have no cartilage in their walls. Their patency depends entirely on the elastic recoil of the surrounding smooth muscle and on the alveolar pressure. The bronchioles contain submucosal glands, which produce mucus that covers the inside lining of the airways. The bronchi and bronchioles are also lined with cells that have surfaces covered with cilia. These cilia create a constant whipping motion that propels mucus and foreign substances away from the lungs toward the larynx.

The bronchioles then branch into terminal bronchioles, which do not have mucus glands or cilia. Terminal bronchioles then become respiratory bronchioles, which are considered to be the transitional passageways between the conducting airways and the gas exchange airways. Up to this point, the conducting airways contain about 150 mL of air in the tracheobronchial tree that does not participate in gas exchange; this is known as physiologic dead space. The respiratory bronchioles then lead into alveolar ducts and alveolar sacs and then alveoli. Oxygen and carbon dioxide exchange takes place in the alveoli.

Alveoli

The lung is made up of about 300 million alveoli, which are arranged in clusters of 15 to 20. These alveoli are

so numerous that if their surfaces were united to form one sheet, it would cover 70 square meters—the size of a tennis court.

There are three types of alveolar cells. Type I alveolar cells are epithelial cells that form the alveolar walls. Type II alveolar cells are metabolically active. These cells secrete surfactant, a phospholipid that lines the inner surface and prevents alveolar collapse. Type III alveolar cell macrophages are large phagocytic cells that ingest foreign matter (eg, mucus, bacteria) and act as an important defense mechanism.