Correlation among mean central venous pressure, mean pulmonary wedge pressure, and cardiac output after acute hemorrhage and replacement with ringer's lactate solution in the dog

Abstract

1. 1. The relationships between MCVP, MPWP, and cardiac output were evaluated in three groups of dogs, two groups of which were bled 22 per cent and 32 per cent of their blood volume, respectively, and which received 4 cc of Ringer's lactate solution per cc of shed blood as replacement. The third group was not bled but received Ringer's lactate solution in a similar ratio to simulate replacement of a 30 per cent blood loss. 2. 2. Changes in MCVP and MPWP were slight and did not correlate with cardiac output, and neither pressure offered any significant information about the changes in cardiac output observed. 3. 3. Peripheral vascular resistance varied inversely with cardiac output whereas MCVP, MPAP, and MPWP remained relatively constant. The plasma oncotic pressure fell and remained significantly below control levels. 4. 4. Development of interstitial pulmonary edema may account for the rise in PVR and concomitant fall in cardiac output. However, because of a rise also in systemic peripheral resistance, this fall in cardiac output more likely was secondary to the equilibration and loss of the infused fluid from the intravascular compartment. 5. 5. In any event, these changes were not heralded by changes in the central venous pressure or pulmonary wedge pressure.