A 42-yrs-old man has had a rocky course for the 3 days

Discussion in 'MRCS Forum' started by Lona., Dec 9, 2007.

  1. Lona.

    Lona. Guest

    A 42-yrs-old man has had a rocky course for the 3 days following a bowel resection of 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. The cause is most likely -
    a- Pulmonary embolism
    b- Hypervolemia
    c- Positive-pressure ventilation
    d- Pneumothorax
    e- Gram-negative sepsis
  2. Lona.

    Lona. Guest

    Answer: e. (Schwartz, 7/e, pp 487-493) determination of CVP has been 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 artifatual 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.

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