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.