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Chapter: Medical Surgical Nursing: Assessment of Cardiovascular Function

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Assessment of Cardiovascular Function: Cardiac Auscultation - Physical Assessment

Assessment of Cardiovascular Function: Cardiac Auscultation - Physical Assessment
Medical Surgical Nursing: Assessment of Cardiovascular Function

Cardiac Auscultation

 

All areas identified in Figure 26-6, except the epigastric area, are auscultated. These include the aortic area, the pulmonary area, Erb’s point, the tricuspid area, and the apical area. The actions of the four valves are uniquely reflected at specific locations on the chest wall. These locations do not correspond to the anatomic lo-cations of the valves within the chest; rather, they reflect the pat-terns by which heart sounds radiate toward the chest wall. Sound in vessels through which blood is flowing is always reflected downstream. For example, the actions of the mitral valve are usu-ally heard best in the fifth intercostal space at the midclavicular line. This is called the mitral valve area.


 

HEART SOUNDS

 

The normal heart sounds, S1 and S2, are produced primarily by the closing of the heart valves. The time between S1 and S2 cor-responds to systole (Fig. 26-8). This is normally shorter than the time between S2 and S1 (diastole). As the heart rate increases, dias-tole shortens.


 

In normal physiology, the periods of systole and diastole are silent. Ventricular disease, however, can give rise to transient sounds in systole and diastole that are called gallops, snaps, or clicks. Significant narrowing of the valve orifices at times when they should be open, or residual gapping of valves at times when they should be closed, gives rise to prolonged sounds called murmurs.

 

S1—First Heart Sound. Closure of the mitral and tricuspid valvescreates the first heart sound (S1), although vibration of the myo-cardial wall also may contribute to this sound. Although S1 is heard over the entire precordium, it is heard best at the apex of the heart (apical area). Its intensity increases when the valve leaflets are made rigid by calcium in rheumatic heart disease and in any circumstance in which ventricular contraction occurs at a time when the valve is caught wide open. The latter circumstance occurs, for example, when a premature ventricular contraction in-terrupts the normal cardiac cycle. S1 varies in intensity from beat to beat when atrial contraction is not synchronous with ventric-ular contraction. This is because the valve may be fully or partially closed on one beat and open on the subsequent one as a function of irregular atrial activity. S1 is easily identifiable and serves as the point of reference for the remainder of the cardiac cycle.

S2—Second Heart Sound. Closing of the aortic and pulmonicvalves produces the second heart sound (S2). Although these two valves close almost simultaneously, the pulmonic valve usually lags slightly behind. Therefore, under certain circumstances, the two components of the second sound may be heard separately (split S2). The splitting is more likely to be accentuated on inspiration and to disappear on exhalation. (More blood is ejected from the right ventricle during inspiration than during exhalation.)

 

S2 is heard loudest at the base of the heart. The aortic compo-nent of S2 is heard clearly in both the aortic and pulmonic areas, and less clearly at the apex. The pulmonic component of S2, if present, may be heard only over the pulmonic area. Therefore, one may hear a “single” S2 in the aortic area and a split S2 in the pulmonic area.

 

Gallop Sounds. If the blood filling the ventricle is impededduring diastole, as occurs in certain disease states, then a tem-porary vibration may occur in diastole that is similar to, although usually softer than, S1 and S2. The heart sounds then come in triplets and have the acoustic effect of a galloping horse; they are called gallops. This may occur early in diastole, during the rapid-filling phase of the cardiac cycle, or later at the time of atrial contraction.

 

A gallop sound occurring during rapid ventricular filling is called a third heart sound (S3); it represents a normal finding in children and young adults (Fig. 26-9A). Such a sound is heard in patients who have myocardial disease or in those who have HF and whose ventricles fail to eject all of their blood during systole. An S3 gallop is heard best with the patient lying on the left side.


 

Gallop sounds heard during atrial contraction are called fourth heart sounds (S4) (see Fig. 26-9B). An S4 is often heard when the ventricle is enlarged or hypertrophied and therefore resistant to filling. Such a circumstance may be associated with CAD, hyper-tension, or stenosis of the aortic valve. On rare occasions, all four heart sounds are heard within a single cardiac cycle, giving rise to what is called a quadruple rhythm.


Gallop sounds are very low-frequency sounds and may be heard only with the bell of the stethoscope placed very lightly against the chest. They are heard best at the apex, although occa-sionally, when emanating from the right ventricle, they may be heard to the left of the sternum.

 

Snaps and Clicks. Stenosis of the mitral valve resulting fromrheumatic heart disease gives rise to an unusual sound very early in diastole that is high-pitched and is best heard along the left sternal border. The sound is caused by high pressure in the left atrium with abrupt displacement of a rigid mitral valve. The sound is called an opening snap. It occurs too long after S2 to be mistaken for a split S2 and too early in diastole to be mistaken for a gallop. It almost always is associated with the murmur of mitral stenosis and is specific to this disorder.

 

In a similar manner, stenosis of the aortic valve gives rise to a short, high-pitched sound immediately after S1 that is called an ejection click. This is caused by very high pressure within the ven-tricle, displacing a rigid and calcified aortic valve.

 

Murmurs. Murmursare created by the turbulent flow of blood.The causes of the turbulence may be a critically narrowed valve, a malfunctioning valve that allows regurgitant blood flow, a con-genital defect of the ventricular wall, a defect between the aorta and the pulmonary artery, or an increased flow of blood through a normal structure (eg, with fever, pregnancy, hyperthyroidism). Murmurs are characterized and consequently described by several characteristics, including timing in the cardiac cycle, location on the chest wall, intensity, pitch, quality, and pattern of radiation (Chart 26-3).


 

Friction Rub. In pericarditis, a harsh, grating sound that can beheard in both systole and diastole is called a friction rub. It is caused by abrasion of the pericardial surfaces during the cardiac cycle. Because a friction rub may be confused with a murmur, care should be taken to identify the sound and to distinguish it from murmurs that may be heard in both systole and diastole. A peri-cardial friction rub can be heard best using the diaphragm of the stethoscope, with the patient sitting up and leaning forward.

 

AUSCULTATION PROCEDURE

 

During auscultation, the patient remains supine and the exam-ining room is as quiet as possible. A stethoscope with a diaphragm and a bell is necessary for accurate auscultation of the heart.

 

Using the diaphragm of the stethoscope, the examiner starts at the apical area and progresses upward along the left sternal bor-der to the pulmonic and aortic areas. If desired, the examiner may choose to begin the examination at the aortic and pulmonic areas and progress downward to the apex of the heart. Initially, S1 is identified and evaluated with respect to its intensity and splitting. Next, S2 is identified, and its intensity and any splitting are noted. After concentrating on S1 and S2, the examiner listens for extra sounds in systole and then in diastole.

 

Sometimes it helps to ask the following questions: Do I hear snapping or clicking sounds? Do I hear any high-pitched blowing sounds? Is this sound in systole, or diastole, or both? The examiner again proceeds to move the stethoscope to all of the designated areas of the precordium, listening carefully for these sounds. Finally, the patient is turned on the left side and the stethoscope is placed on the apical area, where an S3, an S4, and a mitral murmur are more readily detected.

 

Once an abnormality is heard, the entire chest surface is re-examined to determine the exact location of the sound and its radiation. Also, the patient, who may be concerned about the prolonged examination, must be supported and reassured. The auscultatory findings, particularly murmurs, are documented by identifying the following characteristics:

 

·      Location on chest wall.

 

·      Timing of sound as either during systole or during diastole; described as early, middle, or late. (If heard throughout the systole, the sound is often referred to as pansystolic or holosystolic.)

 

·      Intensity of the sound (I, very faint; II, quiet; III, moder-ately loud; IV, loud; V, very loud; or VI, heard with stetho-scope removed from the chest).

 

·      Pitch, desrcribed as high, medium, or low.

 

·        Quality of the sound, commonly described as blowing, harsh, or musical.

 

·      Location of radiation of the sound away from where it is heard the loudest.

 

INTERPRETATION OF CARDIAC SOUNDS

 

Interpreting cardiac sounds requires detailed knowledge of car-diac physiology and the pathophysiology of cardiac diseases. There are different levels of performance at which the nurse may be expected to function. The first level is simply recognizing that what one is hearing is not normal—such as a third heart sound, a murmur in systole or diastole, a pericardial friction rub over the midsternum, or a second heart sound that is widely split. These findings are reported to the physician and acted on accordingly. This level of function is useful in screening. It is the kind of ac-tivity involved in performing physical examinations in schools on normal children or in performing routine physical examinations or screening examinations.

 

The second level involves recognizing patterns. The nurse cor-rectly observes the findings and can recognize the constellation of sounds and the diagnostic significance of common ones.

 

At its most sophisticated level, cardiac diagnosis can be inter-pretive. Highly skilled nurses can differentiate among dysrhyth-mias and respond accordingly. They can determine the significance of the appearance and disappearance of gallops during the treat-ment of patients who have had MIs or who have HF. This is the role that the coronary care nurse and the cardiovascular advanced practice nurse assume. They function with a team of other health care professionals who have highly tuned skills of cardiovascular assessment and diagnosis.

 

Inspection of the Extremities

 

The hands, arms, legs, and feet are observed for skin and vascu-lar changes. The most noteworthy changes include the following:

 

·      Decreased capillary refill time indicates a slower peripheral flow rate from sluggish reperfusion and is often observed in patients with hypotension or HF. Capillary refill time pro-vides the basis for estimating the rate of peripheral blood flow. To test capillary refill, briefly compress the nailbed so that it blanches, and then release the pressure. Normally, reperfusion occurs within 3 seconds, as evidenced by the re-turn of color.

 

·       Vascular changes from decreased arterial circulation include decrease in quality or loss of pulse, discomfort or pain, paresthesia, numbness, decrease in temperature, pallor, and loss of movement. During the first few hours after invasive cardiac procedures (eg, cardiac catheterization), affected ex-tremities should be assessed for vascular changes frequently.

 

·       Hematoma, or a localized collection of clotted blood in the tissue, may be observed in patients who have undergone in-vasive cardiac procedures such as cardiac catheterization, PTCA, or cardiac electrophysiology testing. Major blood vessels of the arms and legs are selected for catheter insertion. During these procedures, systemic anticoagulation with heparin is necessary, and minor or small hematomas may occur at the catheter puncture site. However, large hematomas are a serious complication that can compromise circulating blood volume and cardiac output, requiring blood trans-fusions. All patients who have undergone these procedures must have their puncture sites frequently observed until hemostasis is adequately achieved.

 

·        Peripheral edema is fluid accumulation in dependent areas of the body (feet and legs, sacrum in the bedridden patient). Assess for pitting edema (a depression over an area of pres sure) by pressing firmly for 5 seconds with the thumb over the dorsum of each foot, behind each medial malleolus, and over the shins. Pitting edema is graded as absent or as present on a scale from slight (1+ = 0 to 2 mm) to very marked (4+ = more than 8 mm). Peripheral edema is observed in pa-tients with HF and in those with peripheral vascular diseases such as deep vein thrombosis or chronic venous insufficiency.

 

·       Clubbing of the fingers and toes implies chronic hemoglo-bin desaturation, as in congenital heart disease.

 

·      Lower extremity ulcers are observed in patients with arte-rial or venous insufficiency.

 

Other Systems

 

LUNGS

 

Findings frequently exhibited by cardiac patients include the following:

 

Tachypnea: Rapid, shallow breathing may be noted in patientswho have HF or pain, and in those who are extremely anxious.

 

Cheyne-Stokes respirations: Patients with severe left ventricularfailure may exhibit Cheyne-Stokes breathing, a pattern of rapid respirations alternating with apnea. It is important to note the duration of the apnea.

 

Hemoptysis: Pink, frothy sputum is indicative of acute pul-monary edema.

 

Cough: A dry, hacking cough from irritation of small airways iscommon in patients with pulmonary congestion from HF.

 

Crackles: HF or atelectasis associated with bed rest, splintingfrom ischemic pain, or the effects of pain medications and sedatives often results in the development of crackles. Typically, crackles are first noted at the bases (because of gravity’s effect on fluid accumulation and decreased venti-lation of basilar tissue), but they may progress to all portions of the lung fields.

 

Wheezes: Compression of the small airways by interstitial pul-monary edema may cause wheezing. Beta-adrenergic block-ing agents (beta-blockers), such as propranolol (Inderal), may precipitate airway narrowing, especially in patients with underlying pulmonary disease.

 

ABDOMEN

 

For the cardiac patient, two components of the abdominal ex-amination are frequently performed.

 

Hepatojugular reflux: Liver engorgement occurs because of de-creased venous return secondary to right ventricular failure. The liver is enlarged, firm, nontender, and smooth. The hepatojugular reflux may be demonstrated by pressing firmly over the right upper quadrant of the abdomen for 30 to 60 seconds and noting a rise of 1 cm or more in jugular venous pressure. This rise indicates an inability of the right side of the heart to accommodate increased volume.

 

Bladder distention: Urine output is an important indicator ofcardiac function, especially when urine output is reduced. This may indicate inadequate renal perfusion or a less seri-ous problem such as one caused by urinary retention. When the urine output is decreased, the patient needs to be assessed for a distended bladder or difficulty voiding. The bladder may be assessed with an ultrasound scanner or the suprapubic area palpated for an oval mass and per-cussed for dullness, indicative of a full bladder.

 

Gerontologic Considerations

 

When performing a cardiovascular examination on an elderly patient, the nurse may note such differences as more readily palpable peripheral pulses because of increased hardness of the arteries and a loss of adjacent connective tissue. Palpation of the precordium in the elderly is affected by the changes in the shape of the chest. For example, a cardiac impulse may not be pal-pable in patients with chronic obstructive pulmonary disease, because these patients usually have an increased anterior-posterior chest diameter. Kyphoscoliosis, a spinal deformity that occurs fre-quently in elderly patients, may dislocate the cardiac apex down-ward so that the diagnostic significance of palpating the apical impulse is obscured.

 

Systolic BP increases with age, but diastolic BP usually plateaus after 50 years. Medication therapy is usually initiated for high BP when consistent systolic readings of 160 mm Hg or diastolic read-ings of 95 mm Hg are observed. For the elderly patient, however, many factors are considered before initiating treatment. Ortho-static hypotension may reflect a decreasing sensitivity of postural reflexes, which must be considered when medication therapy is prescribed.

 

An S4 is heard in about 90% of elderly patients; this is thought to be caused by decreased compliance of the left ventri-cle. The S2 is usually split. At least 60% of elderly patients have murmurs, the most common being a soft systolic ejection mur-mur resulting from sclerotic changes of the aortic leaflets (see Table 26-1).


 

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