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Diagnostic value of the physical examination in patients with dyspnea

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CONGESTIVE HEART FAILURE

The clinical presentation of acute congestive heart failure has much in common with pneumonia, pleural effusion, and COPD.

Echocardiography, the gold standard for diagnosis, is costly and may not be immediately available for most patients evaluated for cardiorespiratory complaints. The American College of Cardiology reports the cost of standard echocardiography to be between $1,000 and $2,000.22 A physical examination approach in the assessment of dyspnea can be very useful.

Height of jugular venous distention approximates central venous pressure

Assessing the central venous pressure by estimating the vertical height of distention of the right internal or external jugular vein is validated and easily reproducible.23,24 The use of the external jugular vein is supported by correlation with catheter-measured central venous pressure in critically ill patients.25,26 The central venous pressure reflects the right atrial pressure, and in the absence of tricuspid stenosis, the right ventricular end-diastolic pressure. An elevation in central venous pressure can be seen in patients with congestive heart failure, pulmonary hypertension, and pulmonary valve stenosis.

The right side is preferred due to its anatomically direct route to the heart. In contrast, the left internal jugular vein crosses the mediastinum and can be compressed by the aorta, causing a false elevation.

Signs of congestive heart failure
Examination of the jugular venous pressure has good accuracy in the evaluation of elevated central venous pressure. Examination of the neck veins can detect a central venous pressure elevation of 8 cm with a positive likelihood ratio of 9.7 and a corresponding negative likelihood ratio of 0.3.23–26 Detecting a jugular venous pressure elevation of 12 cm results in a positive likelihood ratio of 10.4 and a negative likelihood ratio of 0.1 (Table 5).23,24

In summary, an elevated jugular venous pressure on examination is a good test to rule in an elevated central venous pressure, and its absence is a good sign in ruling out an elevated central venous pressure. When using jugular venous pressure specifically for the diagnosis of congestive heart failure with reduced ejection fraction (ie, ejection fraction < 50%), the positive likelihood ratio is 6.3 based on 3 studies.25–27

Heart failure with preserved ejection fraction has not been well studied for physical examination. The Irbesartan in Heart Failure with Preserved Ejection Fraction Trial (I-Preserve)28 looked only at the sensitivity of elevated jugular venous pressure in 4,128 patients, which was 8%. Specificity was not reported.

The abdominojugular reflex

Another way to gauge the jugular venous pressure is to examine the neck veins while firmly pressing on the mid-abdomen for 10 to 15 seconds to look for the abdominojugular reflex, also known as the hepatojugular reflex. An increase in the jugular venous pressure of 3 cm from baseline constitutes a positive abdominojugular reflex. It has a positive likelihood ratio of 8.0 and a negative likelihood ratio of 0.3 for the diagnosis of congestive heart failure by the assessment of end-diastolic pressure of the left ventricle (Table 5).29–31

The abdominojugular reflex is a much more reliable test than examination of neck veins for jugular venous pressure. The interobserver agreement for examining neck veins has a wide range of kappa scores (0.08–0.81), whereas the abdominojugular reflex has a very high kappa score of 0.92.7 Interestingly, chest radiography showing interstitial edema has a kappa of 0.83.7

Displaced apical impulse

An evaluation of the apical impulse of the heart is also a very good and quick test in the examination of patients suspected of having congestive heart failure. An abnormal finding is defined by an apical impulse displaced laterally (to the left of the midclavicular line).

Using data from several studies,32–35 a displaced apical impulse has a positive likelihood ratio of 10.3. The absence of this finding, however, is not very good for ruling out congestive heart failure, with a negative likelihood ratio of 0.7. Interobserver agreement is moderate to excellent (kappa score 0.43–0.86).7

A third heart sound

Auscultation to assess the third heart sound is much more difficult. A systematic review found that likelihood ratios vary widely and confidence intervals are wide.36 Interobserver agreement also varies widely (kappa scores –0.17 to 0.84).7 In a primary care study,37 a third heart sound had a very low sensitivity (4.3%) but a specificity of 99.8%.

Therefore, we are uncertain about a conclusion for this physical finding based on the concern for wide ranges in likelihood ratio and poor interobserver reliability.

PHYSICAL EXAMINATION STILL HAS A FUTURE

The physical examination has a long and distinguished place in the history of medicine. Technologic advances have changed the manner in which clinicians practice the art of healing. Modern technology in US healthcare has become a double-edged sword, with many benefits as well as detriments.3 Reproducibility and accuracy are paramount for the physical examination to remain a core component of medical diagnosis. Advances in the diagnostic accuracy of laboratory and imaging studies challenge the importance of the physical examination. However, we firmly believe that the traditional techniques have stood the test of time and have a future in the clinical practice of medicine.

Acknowledgments: The authors thank Ruby Marr, MD, Mohammed Nabhan, MD, Rajiv Doddamani, MD, and Sohaib Galani, MD, for their important contributions to this article, which included research assistance and editorial advice.

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