A PA catheter records CVP 2 mmHg, PAP 8 mmHg (mean), PCWP 3 mmHg, Qt 2.5 L/min. Which is the most likely cause of these results?

• A. High PEEP effects
• B. Hemorrhage
• C. Overhydration
• D. Pulmonary hypertension

Answer: (B)

These numbers show a reduced preload with decreased overall blood volume and a resulting drop in cardiac output. The filling pressures are low: CVP of 2 mmHg and PCWP of 3 mmHg indicate the right and left sides of the heart aren’t being filled with enough blood. The mean PAP of 8 mmHg is within normal limits, so there isn’t a primary rise in pulmonary vascular pressures. The low cardiac output of 2.5 L/min fits with hypovolemia.

Hemorrhage is the most likely cause because bleeding lowers intravascular volume, directly causing low preload pressures and reduced Qt. The other options don’t fit: high PEEP would tend to raise filling pressures or at least not produce this pattern of low preload with low output; overhydration would raise CVP and PCWP; pulmonary hypertension would elevate PAP (and often PCWP) rather than leave them low.