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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5537_Библиотеки_им_академика_М_И_Перельмана.pdf
Cardiac Murmurs
This section will focus on three common left-sided heart murmurs for
which the physical exam has good evidence: the systolic murmurs of aortic stenosis (AS) and mitral regurgitation (MR) and the diastolic murmur
of aortic insufficiency (AI).
Systolic Murmurs
The presence of a systolic murmur during cardiac auscultation can be classified as functional or pathologic (and related to underlying cardiac structural
defects). Aortic stenosis and mitral regurgitation are the two most common
pathologic reasons for systolic murmurs. Aortic stenosis affects up to 25% of
the population over the age of 65. Significant mitral regurgitation affects up
to 2% of the population. Other structural causes of systolic murmurs (such
as hypertrophic cardiomyopathy, tricuspid regurgitation, or mitral valve
prolapse) and non-structural causes (such as anemia, thyrotoxicosis, or
sepsis) must also be considered in the patient with a systolic murmur.
Most of the studies evaluating the utility of the clinical exam for
distinguishing systolic murmurs were performed by cardiologists. There
is very little data on the accuracy and precision of non-cardiologists for
evaluating cardiac murmurs. The following likelihood ratios reflect cardiologist examinations.
Aortic Stenosis
Historical findings in patients with aortic stenosis (AS) are often nonspecific — many patients are asymptomatic. Patients with more advanced
disease, however, may have any of the triad of shortness of breath, angina
or syncope in varying degrees. The presence of effort syncope (transient
loss of consciousness during effort or exertion) is the only historical finding that is consistently associated with AS. In a patient with a systolic
murmur, the LR+ of a history of effort syncope approaches infinity and
therefore, is diagnostic for the presence aortic stenosis.
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The most useful physical exam findings for detecting AS include:
• slow rise in carotid upstroke (LR+ 2.8–130)
• peak murmur intensity in late or midsystole (LR+ 8–101)
• reduced (or absent) S2 (LR+ 3.1–50)
• apical-carotid delay (LR+
∞)
• brachioradial delay (LR+ 6.8)
Absence of a systolic murmur (LR − 0) or lack of radiation to the right
carotid (LR − 0.05–0.10) significantly decrease the likelihood of AS. A
multivariable decision rule incorporating these findings for suspected aortic stenosis has been described.
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How to Perform the Useful Physical Exam for Aortic Stenosis
Ausculatation: Area of maximal intensity is over the second right intercostal space. Listen for radiation to the right carotid and right clavicle.
Apical-Carotid Delay: Simultaneously palpate the precordial apex at the
point of maximal impulse and the right carotid artery. Any palpable delay
between the pulsation of the apex and the carotid is abnormal.
Brachioradial Delay: Simultaneously palpate the patient’s right brachial
artery with your right thumb and his right radial artery with your left index
and middle finger. Use light pressure on the brachial artery — this avoids
diminishing the waveform. Any palpable delay between the pulses of
these two arteries is considered abnormal.
Mitral Regurgitation
Patients with chronic mitral regurgitation (MR) are often asymptomatic.
Some may complain of symptoms consistent with congestive heart failure
and these patients are very prone to volume overload. Acute MR will
cause acute decompensated congestive heart failure and signs/symptoms
of cardiogenic shock.
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On physical exam, the presence of a murmur in the 5th intercostal
space with radiation to the axilla slightly increases the likelihood of MR
(LR+ 3.6–3.9). Absence of a murmur, however, more significantly rules
out MR (LR− 0.12–0.34). Increased murmur intensity significantly correlates with severity of regurgitation (Murmur grades 4–5 LR+ 14, grade 3
LR+ 3.5). Increased murmur intensity with transient arterial occlusion
helps to rule in MR (LR+ 7.5, LR− 0.28). Studies in non-cardiologists
showed lower accuracy in diagnosing MR than studies performed with
cardiologists.
How to Examine the Useful Physical Exam for Mitral Regurgitation
Auscultation: Location of maximal intensity is over the 5th or 6th intercostal space, mid left thorax with radiation to left axilla.
Transient Arterial Occlusion: Sphygmomanometers are placed on the
patient’s arms and inflated to 20–40 mmHg above the patient’s current systolic blood pressure. The murmur is auscultated 20 seconds after cuff inflation
and changes in murmur intensity are noted. The murmur of mitral regurgitation will intensify due to increased systemic arterial resistance and backflow
across the valve. This maneuver will increase the intensity of other left-sided
regurgitant murmurs as well. (See section on “Aortic Insufficiency.”)
Diastolic Murmurs
Aortic Insufficiency
Aortic insufficiency, characterized by incompetence of the aortic valve
leaflets or inability to approximate due to aortic root dilatation, is a valvular
abnormality associated with a variety of serious underlying cardiac pathologies. Detection of aortic insufficiency from the history and physical exam
can help clarify which patients require more definitive cardiac imaging, such
as echocardiography or cardiac catheterization with angiography.
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Patients with aortic regurgitation are often asymptomatic. The
Framingham heart study detected a prevalence of some degree of aortic
insufficiency in 13% of men and 8.5% of women in their cohort. Some
patients may report a sensation of pounding in the chest or awareness of
the heartbeat, especially when lying supine or on the left side. Others may
describe atypical chest pain or palpitations.
There are a variety of eponymous physical exam findings
described for aortic insufficiency along with the characteristic early
diastolic decrescendo murmur best appreciated at the right upper
sternal border. Many of the peripheral hemodynamic signs (such as de
Musset’s head bobbing, widened pulse pressure, and Duroziez’s
femoral murmur) have been evaluated but have little predictive
value for diagnosing aortic insufficiency. Other signs have not been
evaluated, such as Mueller’s pulsatile uvula and Quincke’s capillary
pulsation.
The most useful physical exam findings are the typical early diastolic
murmur of aortic insufficiency (LR+ 4–8.3; LR− 0.1–0.3), increased
murmur intensity with transient arterial occlusion (LR+ 8.4; LR– 0.3), and
the presence of an S3 on cardiac auscultation (LR+ 5.9).
How to Perform the Useful Physical Exam for Aortic Insufficiency
Auscultation: The murmur of AI will be best heard at the right upper
sternal border or the lower left sternal border and may be accentuated by
the patient leaning forward or lying in the left lateral decubitus position.
Place the diaphragm of the stethoscope firmly on the chest wall to hear
this high pitched, early-diastolic, decrescendo blowing murmur. S2 may
be obscured.
Transient Arterial Occlusion: (See section on “Mitral Regurgitation”).
The murmur of aortic insufficiency will intensify due to increased
systemic arterial resistance and backflow across the aortic valve —
inter-examiner.
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Hepatomegaly
The reference standard for hepatomegaly, the enlargment of the liver
beyond its normal size, is ultrasonography or nuclear scintigraphy.
Although there is normal variation in liver size with gender and height,
95% of normal adult livers have a sonographic span at the mid-clavicular
line of ≤ 12.5 cm. A span of more than 12 or 13 cm measured on physical exam increases the probability of hepatomegaly. Inaccuracies of the
physical exam for measuring liver span include a tendency to underestimate span as well as interexaminer variability. Formulas have been
developed which take into account gender, body weight and height in
determining expected normal span but are cumbersome for the clinical
setting.
Palpating a liver edge below the costal margin moderately increases
the likelihood that the patient has hepatomegaly (LR+ 2.5); however, over
half of palpable livers are not enlarged. Similarly, failure to identify a liver
edge does reduce the probability of a hepatomegaly but does not rule it out
(LR− 0.41). Palpation specifically to assess the quality of the liver edge is
recommended only if there are other signs of liver disease.
How to Perform the Useful Physical Exam to Assess Hepatomegaly
Start with gentle pressure in the RLQ; have the patient breathe in gently
to bring the liver edge down to the examining fingertips. At each exhalation, move the fingers up about 2 cm. If a lower edge is palpated, mark the
lower edge at the mid-clavicular line (MCL). To measure the vertical
span, percuss down from about the level of the 3rd rib at the MCL until
the tone changes. To confirm increasing dullness, spread two or three fingers over the adjacent rib spaces and percuss quickly a number of times
from greater to lesser resonance. If doubts persist, have the patient take a
deeper breath and hold it; then percuss to confirm an unequivocal increase
in resonance at that rib space. The upper and lower borders should be
marked either in quiet respiration or the same phase of respiration.
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In patients with an unpalpable liver edge, and a high probability of
liver disease, span may be measured by percussion alone, although it is
less accurate in detecting hepatomegaly than when a palpated lower edge
can be used for the lower border. Attempt to locate the lower edge by gentle percussion in the RUQ at the MCL.
Ascites
Ascites, the presence of free fluid within the abdomen is easily detected
when it is present in large volumes. When small amounts of fluid are present, the diagnosis is less certain. The reference standard for detecting ascites
is paracentesis or fluid visualization with imaging studies. Ultrasonography
is most commonly used and can detect as a little as 100 mL of abdominal
fluid which is much smaller than can be detected by physical exam.
Patients with ascites may report increased abdominal girth, recent
weight gain and ankle swelling. The patient’s history is most useful when
ruling out ascites. An absence of recent ankle swelling (LR− 0.10) or
increased abdominal girth (LR− 0.17) are helpful findings.
Common physical exam findings include bulging flanks, flank dullness, shifting dullness, fluid wave and Puddle sign. The most useful physical exam findings are the presence of a fluid wave (LR+ 5.3) and shifting
dullness (LR+ 2.1).
How to Perform the Useful Physical Exam to Assess for Ascites
Fluid wave: A second examiner (or the patient) places a hand, pressing
firmly down on the midline of the abdomen. This pressure will stop the
transmission of an impulse through adipose tissue. The examiner then taps
one flank of the patient’s abdomen while palpating for a transmitted fluid
wave on the other flank.
Shifting dullness: Percuss the abdomen, marking the borders of tympany
and dullness. Ask the patient to turn on one side. In the presence of ascites
the border between tympany and dullness will rise.
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Central Venous Pressure
Central venous pressure, the pressure of blood in the thoracic vena cavae, is
useful in assessing intravascular volume status, ventricular function, and
obstruction to right ventricular inflow or outflow. Bedside evaluation of jugular venous pressure can facilitate the estimation of CVP. CVP can be approximated as JVP measured from the sternal angle + 5 cm, as 5 cm is the estimated
distance between the sternal angle and the zero point at the mid-right atrium.
This approach has been challenged because the distance between the
sternal angle and mid-right atrium varies considerably. Another approach to
CVP estimation is to look for venous pulsation above the clavicle in a seated
patient. If any pulsation above the clavicle is seen, the CVP can be assumed
to be elevated, since the clavicle is at least 10 cm above the mid-atrium.
Despite the variation in mid-right atrial location, bedside JVP measurement can help qualify CVP as low normal or high. A JVP ≥3 cm above
the sternal angle, or a sustained increase in JVP of ≥4 cm with abdominal
compression, suggests a 3–4-fold increase in the likelihood that the CVP
is abnormally elevated. When JVP is 0–2 cm above the sternal angle, this
does not help rule out high or low CVP.
Evaluation of JVP
The head is supported to relax the neck muscles; the trunk is inclined at an
angle (35–45°) which brings the meniscus of the right internal jugular
venous pulse above the clavicle but below the jaw. Patients with low CVP
may need an angle of 0–30°. In patients with an elevated CVP, the angle
may be > 45°; patients with severe congestion may have to stand and
inspire to bring the meniscus down into view. A penlight directed away
from examiners eyes is often helpful. JVP is the vertical distance measured
from the sternal angle to the meniscus of the right internal jugular pulse.
Abdominojugular Reflux Test
The patient is instructed to relax and breathe normally through an open
mouth (to avoid false-positive increase in JVP from Valsalva maneuver.)
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J. K. Stulman, C. Bigelow and S. Kahane
Firm pressure is applied with the palm to the mid-abdomen for 15–30 seconds. Positive test occurs when abdominal compression causes a sustained increase in JVP ≥4 cm. The abdominojugular reflux test is not
sensitive for diagnosing CHF but has a high specificity (LR+ 6.4).
Kussmaul Sign
The Kussmaul sign is the paradoxic increase in JVP during inspiration,
and can be seen when the heart cannot accommodate the increased venous
return during inspiration, such as in constrictive pericarditis or severe
right-sided heart failure.
Pleural Effusion
Pleural effusion is common in patients presenting with respiratory complaints. The most common symptoms of pleural effusion, chest pain and
dyspnea are however, nonspecific. The accuracy of specific physical exam
maneuvers in detecting pleural effusion is an important consideration in
determining which patients should receive confirmatory imaging studies.
A systematic review of studies compared eight physical exam maneuvers
(conventional percussion, auscultory percussion, breath sounds, chest expansion, tactile vocal fremitus, vocal resonance, crackles, and pleural friction rub)
with radiographic confirmation of pleural effusions. Dullness to conventional
percussion (LR+ 8.7) and asymmetric chest expansion (LR+ 8.1) were the
most accurate for diagnosing pleural effusion, while the absence of reduced
tactile vocal fremitus made pleural effusion less likely (LR− 0.21). Absence
of dullness to percussion cannot be used to rule out pleural effusion in patients
with moderate or high pretest probability (LR− 0.31).
How to Perform the Useful Physical Exam
Conventional Percussion
The clinician should firmly place the second or third finger of the nondominant hand horizontally between the ribs on the patient’s posterior
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chest wall. The second or third finger of the dominant hand should be
slightly flexed, and using the fingertip, the clinician should tap the distal
interphalangeal joint of the firmly placed finger. Starting at the apices and
progressing down to the bases, the left and right hemithoraces should be
compared at equal horizontal planes.
Chest Expansion
Inspect the posterior chest for symmetric movement during inspiration.
Place the hands firmly on the lateral aspect of the thorax to best visualize movement of the hemithoraces in relation to one another. As the
patient breathes, the physician should watch for equal movements of
his/her hands.
Tactile Fremitus
The patient is asked to repeat a phrase such as “ninety-nine” or “toy
boat” while the examiner places the ulnar surface of the hand on the
chest assessing vibrations. Vocal tactile fremitus can also be assessed by
firmly placing the palmar aspect of the hands and fingertips on the
patient’s posterior chest. The intensity of the vibration over all lung
fields should be noted. Decreased tactile fremitus is consistent with
pleural effusion.
References
1. Simel D, Rennie D (eds). (2009) The Rational Clinical Examination.
McGraw Hill, NY.
2. Bickley L, Szilagyi P (eds). (2003) Bate’s Guide to Physical
Examination, 8th ed. Lippincott Philadelphia.
3. Castell DO, O’Brien KD, Muench H, Chalmers TC. (1969) Estimate
of liver size by percussion in normal individuals. Ann Intern Med 70:
1183–1189.
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4. Light RW, Lee YCG (eds.) (2003) Textbook of Pleural Diseases, 2nd
ed. Oxford, England: Oxford University Press (Arnold Publication).
5. Meidl EJ, Ende J. (1993) Evaluation of liver size by physical exami-
nation. J Gen Inter Med 8(11): 635–637, DOI: 10.1007/BF02599724.
6. Rolston D, Diaz-Guzman E, Budev MM. (2008) Accuracy of the
physical examination in evaluating pleural effusion. Cleve Clin J Med
75(4): 297–303.
7. Wong CL, Holroyd-Leduc J, Straus SE. (2009) Does this patient have
a pleural effusion? JAMA 301(3): 309–317.
8. Hoagland PM, Cook EF, Wynne J, Goldman L. (1986) Value of non-
invasive testing in adults with suspected aortic stenosis. AM J Med
60(4): 399–401.
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