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Chapter: Medical Surgical Nursing: Assessment of Cardiovascular Function

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Assessment of Cardiovascular Function: Physical Assessment

Assessment of Cardiovascular Function: Physical Assessment
A physical examination is performed to confirm the data obtained in the health history.

PHYSICAL ASSESSMENT

 

A physical examination is performed to confirm the data obtained in the health history. In addition to observing the patient’s gen-eral appearance, a cardiac physical examination should include an evaluation of the following:

 

·      Effectiveness of the heart as a pump

 

·       Filling volumes and pressures

 

·       Cardiac output

 

·       Compensatory mechanisms

 

Indications that the heart is not contracting sufficiently or functioning effectively as a pump include reduced pulse pressure, cardiac enlargement, and murmurs and gallop rhythms (abnor-mal heart sounds).

 

The amount of blood filling the atria and ventricles and the re-sulting pressures (called filling volumes and pressures) are esti-mated by the degree of jugular vein distention and the presence or absence of congestion in the lungs, peripheral edema, and postural changes in BP that occur when the individual sits up or stands.

 

Cardiac output is reflected by cognition, heart rate, pulse pres-sure, color and texture of the skin, and urine output. Examples of compensatory mechanisms that help maintain cardiac output are increased filling volumes and elevated heart rate. Note that the findings on the physical examination are correlated with data ob-tained from diagnostic procedures, such as hemodynamic moni-toring (discussed later).

 

The examination, which proceeds logically from head to toe, can be performed in about 10 minutes with practice and covers the following areas: (1) general appearance, (2) cognition, (3) skin, BP, (5) arterial pulses, (6) jugular venous pulsations and pressures, (7) heart, (8) extremities, (9) lungs, and (10) abdomen

General Appearance and Cognition

 

The nurse observes the patient’s level of distress, level of conscious-ness, and thought processes as an indication of the heart’s ability to propel oxygen to the brain (cerebral perfusion). The nurse also observes for evidence of anxiety, along with any effects emotional factors may have on cardiovascular status. The nurse attempts to put the anxious patient at ease throughout the examination.

 

Inspection of the Skin

 

Examination of the skin begins during the evaluation of the gen-eral appearance of the patient and continues throughout the as-sessment. It includes all body surfaces, starting with the head and finishing with the lower extremities. Skin color, temperature, and texture are assessed. The more common findings associated with cardiovascular disease are as follows.

·       Pallor—a decrease in the color of the skin—is caused by lack of oxyhemoglobin. It is a result of anemia or decreased arterial perfusion. Pallor is best observed around the finger-nails, lips, and oral mucosa. In patients with dark skin, the nurse observes the palms of the hands and soles of the feet.

 

·       Peripheral cyanosis—a bluish tinge, most often of the nails and skin of the nose, lips, earlobes, and extremities—suggests decreased flow rate of blood to a particular area, which allows more time for the hemoglobin molecule to become desatu-rated. This may occur normally in peripheral vasoconstric-tion associated with a cold environment, in patients with anxiety, or in disease states such as HF.

 

·      Central cyanosis—a bluish tinge observed in the tongue and buccal mucosa—denotes serious cardiac disorders (pulmonary edema and congenital heart disease) in which venous blood passes through the pulmonary circulation without being oxygenated.

 

·      Xanthelasma—yellowish, slightly raised plaques in the skin—may be observed along the nasal portion of one or both eyelids and may indicate elevated cholesterol levels (hypercholesterolemia).

 

·      Reduced skin turgor occurs with dehydration and aging.

 

·       Temperature and moistness are controlled by the auto-nomic nervous system. Normally the skin is warm and dry. Under stress, the hands may become cool and moist. In car-diogenic shock, sympathetic nervous system stimulation causes vasoconstriction, and the skin becomes cold and clammy. During an acute MI, diaphoresis is common.

 

·       Ecchymosis (bruise)—a purplish-blue color fading to green, yellow, or brown over time—is associated with blood out-side of the blood vessels and is usually caused by trauma. Pa-tients who are receiving anticoagulant therapy should be carefully observed for unexplained ecchymosis. In these pa-tients, excessive bruising indicates prolonged clotting times (prothrombin or partial thromboplastin time) caused by an anticoagulant dosage that is too high.

 

·      Wounds, scars, and tissue surrounding implanted devices should also be examined. Wounds are assessed for adequate healing, and any scars from previous surgeries are noted. The skin surrounding a pacemaker or implantable cardio-verter defibrillator generator is examined for thinning, which could indicate erosion of the device through the skin.

 

Blood Pressure

Systemic arterial BP is the pressure exerted on the walls of the ar-teries during ventricular systole and diastole. It is affected by fac-tors such as cardiac output, distention of the arteries, and the volume, velocity, and viscosity of the blood. BP usually is expressed as the ratio of the systolic pressure over the diastolic pressure, with normal adult values ranging from 100/60 to 140/90 mm Hg. The average normal BP usually cited is 120/80 mm Hg. An in-crease in BP above the upper normal range is called hypertension, whereas a decrease below the lower range is called hypotension.

BLOOD PRESSURE MEASUREMENT

BP can be measured with the use of invasive arterial monitoring systems (discussed later) or noninvasively by a sphygmomanometer and stethoscope or by an automated BP monitoring device. A de-tailed description of the procedure for obtaining BP can be found in nursing skills textbooks, and specific manufacturer’s instruc-tions review the proper use of the automated monitoring devices. Several important details must be observed to ensure that BP measurements are accurate; these are highlighted in Chart 26-2.


PULSE PRESSURE

The difference between the systolic and the diastolic pressures is called the pulse pressure. It is a reflection of stroke volume, ejection velocity, and systemic vascular resistance. Pulse pressure, which normally is 30 to 40 mm Hg, indicates how well the patient main-tains cardiac output. The pulse pressure increases in conditions that elevate the stroke volume (anxiety, exercise, bradycardia), reduce systemic vascular resistance (fever), or reduce distensibility of the arteries (atherosclerosis, aging, hypertension). Decreased pulse pres-sure is an abnormal condition reflecting reduced stroke volume and ejection velocity (shock, HF, hypovolemia, mitral regurgitation) or obstruction to blood flow during systole (mitral or aorticstenosis). A pulse pressure of less than 30 mm Hg signifies a serious reduction in cardiac output and requires further cardiovascular assessment.

 

POSTURAL BLOOD PRESSURE CHANGES

 

Postural (orthostatic) hypotension occurs when the BP dropssignificantly after the patient assumes an upright posture. It is usually accompanied by dizziness, lightheadedness, or syncope.

 

Although there are many causes of postural hypotension, the three most common causes in patients with cardiac problems are a reduced volume of fluid or blood in the circulatory system (intra-vascular volume depletion, dehydration), inadequate vasocon-strictor mechanisms, and insufficient autonomic effect on vascular constriction. Postural changes in BP and an appropriate history help health care providers differentiate among these causes. The following recommendations are important when assessing pos-tural BP changes:

 

·      Position the patient supine and flat (as symptoms permit) for 10 minutes before taking the initial BP and heart rate measurements.

 

·      Check supine measurements before checking upright mea-surements.

 

·      Do not remove the BP cuff between position changes, but check to see that it is still correctly placed.

 

·       Assess postural BP changes with the patient sitting on the edge of the bed with feet dangling and, if appropriate, with the patient standing at the side of the bed.

 

·      Wait 1 to 3 minutes after each postural change before mea-suring BP and heart rate.

 

·      Be alert for any signs or symptoms of patient distress. If nec-essary, return the patient to a lying position before com-pleting the test.

 

·       Record both heart rate and BP and indicate the correspond-ing position (e.g., lying, sitting, standing) and any signs or symptoms that accompany the postural change.

 

Normal postural responses that occur when a person stands up or goes from a lying to a sitting position include (1) a heart rate increase of 5 to 20 bpm above the resting rate (to offset reduced stroke volume and maintain cardiac output); (2) an unchanged systolic pressure, or a slight decrease of up to 10 mm Hg; and (3) a slight increase of 5 mm Hg in diastolic pressure.

 

A decrease in the amount of blood or fluid in the circulatory system should be suspected after diuretic therapy or bleeding, when a postural change results in an increased heart rate and either a decrease in systolic pressure by 15 mm Hg or a drop in the diastolic pressure by 10 mm Hg. Vital signs alone do not dif-ferentiate between a decrease in intravascular volume and in-adequate constriction of the blood vessels as a cause of postural hypotension. With intravascular volume depletion, the reflexes that maintain cardiac output (increased heart rate and peripheral vasoconstriction) function correctly; the heart rate increases, and the peripheral vessels constrict. However, because of lost vol-ume, the BP falls. With inadequate vasoconstrictor mechanisms, the heart rate again responds appropriately, but because of di-minished peripheral vasoconstriction the BP drops. The follow-ing is an example of a postural BP recording showing either intravascular volume depletion or inadequate vasoconstrictor mechanisms:

 

Lying down, BP 120/70, heart rate 70

Sitting, BP 100/55, heart rate 90

Standing, BP 98/52, heart rate 94

 

In autonomic insufficiency, the heart rate is unable to increase to completely compensate for the gravitational effects of an up-right posture. Peripheral vasoconstriction may be absent or di-minished. Autonomic insufficiency does not rule out a concurrent decrease in intravascular volume. The following is an example of autonomic insufficiency as demonstrated by postural BP changes:

 

Lying down, BP 150/90, heart rate 60

Sitting, BP 100/60, heart rate 60

 

Arterial Pulses

 

Factors to be evaluated in examining the pulse are rate, rhythm, quality, configuration of the pulse wave, and quality of the arte-rial vessel.

 

PULSE RATE

 

The normal pulse rate varies from a low of 50 bpm in healthy, athletic young adults to rates well in excess of 100 bpm after ex-ercise or during times of excitement. Anxiety frequently raises the pulse rate during the physical examination. If the rate is higher than expected, it is appropriate to reassess it near the end of the physical examination, when the patient may be more relaxed.

 

PULSE RHYTHM

 

The rhythm of the pulse is as important to assess as the rate. Minor variations in regularity of the pulse are normal. The pulse rate, particularly in young people, increases during inhalation and slows during exhalation. This is called sinus arrhythmia.

 

For the initial cardiac examination, or if the pulse rhythm is irregular, the heart rate should be counted by auscultating the apical pulse for a full minute while simultaneously palpating the radial pulse.

 

Any discrepancy between contractions heard and pulses felt is noted. Disturbances of rhythm (dysrhythmias) often result in a pulse deficit, a difference between the apical rate (the heart rate heard at the apex of the heart) and the peripheral rate. Pulse deficits commonly occur with atrial fibrillation, atrial flutter, premature ventricular contractions, and varying degrees of heart block.

 

To understand the complexity of dysrhythmias that may be encountered during the examination, the nurse needs to have a sophisticated knowledge of cardiac electrophysiology, obtained through advanced education and training.

 

PULSE QUALITY

 

The quality, or amplitude, of the pulse can be described as absent, diminished, normal, or bounding. It should be assessed bilater-ally. Scales can be used to rate the strength of the pulse. The fol-lowing is an example of a 0-to-4 scale:

 

0 pulse not palpable or absent

+1  weak, thready pulse; difficult to palpate; obliterated with pressure

+2  diminished pulse; cannot be obliterated

+3  easy to palpate, full pulse; cannot be obliterated

+4  strong, bounding pulse; may be abnormal

 

The numerical classification is quite subjective; therefore, when documenting the pulse quality, it helps to specify a scale range (eg, “left radial +3/+4”).

 

PULSE CONFIGURATION

The configuration (contour) of the pulse conveys important in-formation. In patients with stenosis of the aortic valve, the valve opening is narrowed, reducing the amount of blood ejected into the aorta. The pulse pressure is narrow, and the pulse feels feeble. In aortic insufficiency, the aortic valve does not close completely, allowing blood to flow back or leak from the aorta into the left ventricle. The rise of the pulse wave is abrupt and strong, and its fall is precipitous—a “collapsing” or “water hammer” pulse. The true configuration of the pulse is best appreciated by palpating over the carotid artery rather than the distal radial artery, because the dramatic characteristics of the pulse wave may be distorted when the pulse is transmitted to smaller vessels.

 

EFFECT OF VESSEL QUALITY ON PULSE

 

The condition of the vessel wall also influences the pulse and is of concern, especially in older patients. Once rate and rhythm have been determined, the nurse assesses the quality of the vessel by palpating along the radial artery and comparing it with nor-mal vessels. Does the vessel wall appear to be thickened? Is it tortuous?

 

To assess peripheral circulation, the nurse locates and evalu-ates all arterial pulses. Arterial pulses are palpated at points where the arteries are near the skin surface and are easily compressed against bones or firm musculature. Pulses are detected over the temporal, carotid, brachial, radial, femoral, popliteal, dorsalis pedis, and posterior tibial arteries. A reliable assessment of the pulses of the lower extremities depends on accurate identification of the location of the artery and careful palpation of the area. Light palpation is essential; firm finger pressure can easily oblit-erate the dorsalis pedis and posterior tibial pulses and confuse the examiner. In approximately 10% of patients, the dorsalis pedis pulses are not palpable. In such circumstances, both are usu-ally absent together, and the posterior tibial arteries alone pro-vide adequate blood supply to the feet. Arteries in the extremities are often palpated simultaneously to facilitate comparison of quality.

Jugular Venous Pulsations

 

An estimate of right-sided heart function can be made by observ-ing the pulsations of the jugular veins of the neck. This provides a means of estimating central venous pressure, which reflects right atrial or right ventricular end-diastolic pressure (the pressure immediately preceding the contraction of the right ventricle).

 

Pulsations of the internal jugular veins are most commonly as-sessed. If they are difficult to see, pulsations of the external jugu-lar veins may be noted. These veins are more superficial and are visible just above the clavicles, adjacent to the sternocleido-mastoid muscles. The external jugular veins are frequently dis-tended while the patient lies supine on the examining table or bed. As the patient’s head is elevated, the distention of the veins disappears. The veins normally are not apparent if the head of the bed or examining table is elevated more than 30 degrees.

 

Obvious distention of the veins with the patient’s head elevated 45 degrees to 90 degrees indicates an abnormal increase in the vol-ume of the venous system. This is associated with right-sided HF, less commonly with obstruction of blood flow in the superior vena cava, and rarely with acute massive pulmonary embolism.

 

Heart Inspection and Palpation

 

The heart is examined indirectly by inspection, palpation, per-cussion, and auscultation of the chest wall. A systematic approach is the cornerstone of a thorough assessment. Examination of the chest wall is performed in the following six areas (Fig. 26-6):


 

·        Aortic area—second intercostal space to the right of thesternum. To determine the correct intercostal space, start at the angle of Louis by locating the bony ridge near the top of the sternum, at the junction of the body and the manu-brium. From this angle, locate the second intercostal space by sliding one finger to the left or right of the sternum. Subsequent intercostal spaces are located from this refer-ence point by palpating down the rib cage.

 

·        Pulmonic area—second intercostal space to the left of thesternum

 

·        Erb’s point—third intercostal space to the left of the sternum

 

·        Right ventricular or tricuspid area—fourth and fifth inter-costal spaces to the left of the sternum

 

·        Left ventricular or apical area—the PMI, location on thechest where heart contractions can be palpated

 

·        Epigastric area—below the xiphoid process

 

For most of the examination, the patient lies supine, with the head slightly elevated. The right-handed examiner is positioned at the right side of the patient and the left-handed examiner at the left side.

 

In a systematic fashion, each area of the precordium is inspected and then palpated. Oblique lighting is used to assist the examiner in identifying subtle pulsation. A normal impulse that is distinct and located over the apex of the heart is called the apical impulse (PMI). It may be observed in young people and in older people who are thin. The apical impulse is normally located and auscul-tated in the left fifth intercostal space in the midclavicular line (Fig. 26-7).


 

In many cases, the apical impulse is palpable and is normally felt as a light pulsation, 1 to 2 cm in diameter. It is felt at the onset of the first heart sound and lasts for only half of systole. (See the next section for a discussion of heart sounds.) The nurse uses the palm of the hand to locate the apical impulse initially and the fingerpads to assess its size and quality. A broad and forceful apical impulse is known as a left ventricular heave or lift. It is so named because it appears to lift the hand from the chest wall during palpation.

 

An apical impulse below the fifth intercostal space or lateral to the midclavicular line usually denotes left ventricular enlarge-ment from left ventricular failure. Normally, the apical impulse is palpable in only one intercostal space; palpability in two or more adjacent intercostal spaces indicates left ventricular enlargement. If the apical impulse can be palpated in two distinctly separate areas and the pulsation movements are paradoxical (not simulta-neous), a ventricular aneurysm should be suspected.

 

Abnormal, turbulent blood flow within the heart may be pal-pated with the palm of the hand as a purring sensation. This phe-nomenon is called a thrill and is associated with a loud murmur. A thrill is always indicative of significant pathology within the heart. Thrills also may be palpated over vessels when blood flow is significantly and substantially obstructed and over the carotid ar-teries if aortic stenosis is present or if the aortic valve is narrowed.

 

Chest Percussion

 

Normally, only the left border of the heart can be detected by percussion. It extends from the sternum to the midclavicular line in the third to fifth intercostal spaces. The right border lies under the right margin of the sternum and is not detectable. Enlarge-ment of the heart to either the left or right usually can be noted. In people with thick chests, obesity, or emphysema, the heart may lie so deep under the thoracic surface that not even its left border can be noted unless the heart is enlarged. In such cases, unless the nurse detects a displaced apical impulse and suspects cardiac en-largement, percussion is omitted.

 

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