(BQ) Part 2 book "Evidence based physical diagnosis" has contents: The heart, selected cardiac disorders, abdomen, extremities, neurologic examination, selected neurologic disorders, examination in the intensive care unit. | PA RT THE HEART 8 This page intentionally left blank CHAPTER 34 Inspection of the Neck Veins I. INTRODUCTION Clinicians should inspect the neck veins for the following reasons: 1. detect elevated central venous pressure To 2. detect specific abnormalities of venous waveforms, which are To characteristic of certain arrhythmias and some valvular, pericardial, and myocardial disorders Clinicians first associated conspicuous neck veins with heart disease about three centuries In the late 1800s, Sir James Mackenzie described venous waveforms of arrhythmias and various heart disorders, using a mechanical polygraph applied over the patient’s neck or liver. His labels for the venous waveforms—A, C, and V waves—are still used Clinicians began to estimate venous pressure at the bedside routinely in the 1920s, after the introduction of the glass manometer and after Starling’s experiments linking venous pressure to cardiac II. VENOUS PRESSURE A. DEFINITIONS 1. Central Venous Pressure Central venous pressure (CVP) is the mean vena caval or right atrial pressure, which, in the absence of tricuspid stenosis, equals right ventricular end-diastolic pressure. Disorders that increase diastolic pressures of the right side of the heart—left heart disease, lung disease, primary pulmonary hypertension, and pulmonic stenosis—all increase the CVP and make the neck veins abnormally conspicuous. CVP is expressed in millimeters of mercury (mm Hg) or centimeters (cm) of water above atmospheric pressure ( cm water = 1 mm Hg). Estimations of CVP are most helpful in patients with ascites or edema, in whom an elevated CVP indicates heart or lung disease and a normal CVP suggests alternative diagnoses, such as chronic liver disease. Despite the prevailing opinion, the CVP is normal in patients with liver disease; the edema in these patients results from hypoalbuminemia and the weight of ascites compressing veins to the –9 2. .
