A 42-year-old man has had a rocky course for the 3 days following a bowel resection for intestinal perforation due to inflammatory bowel disease. His CVP had been 12 to 14 but is now 6, in the face of diminished blood pressure and oliguria. Which of the following is the most likely etiology of his hypotension?
Determination of CVP can be helpful in the overall hemodynamic assessment of the patient. This pressure can be affected by a variety of factors, including those of cardiac, noncardiac, and aifactual origin. Venous tone, right ventricular compliance, intrathoracic pressure, and blood volume all influence CVP. Vasoconstrictor drugs, positive-pressure ventilation (with and without PEEP), mediastinal compression, and hypervolemia all increase CVP. Acute pulmonary embolism, when clinically significant, elevates CVP by causing right ventricular overload and increased right atrial pressure. Sepsis, on the other hand, decreases CVP through both the release of vasodilatory mediators and the loss of intravascular plasma volume due to increased capillary permeability. Trends in CVP measurement are more reliable than isolated readings. CVP, along with other hemodynamic parameters, can also be useful in differentiating septic shock from other etiologies of shock; shock is inadequate tissue perfusion. Septic shock has two phases: (1) a hypodynamic phase that is characterized by hypovolemia and myocardial depression and (2) a hyperdynamic phase that follows fluid resuscitation and is characterized by a normal to increased cardiac output
Pulmonary embolism
Hypervolemia
Positive-pressure ventilation
Gram-negative sepsis
Miscellaneous