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B F Cammack

Publications and source records attributed to B F Cammack.

4 recordsLinked to original sources
PubMed1981

Does reduced colloid oncotic pressure increase pulmonary dysfunction in sepsis?

Starling's hypothesis of forces governing fluid movement across capillary membranes suggests that any unopposed decrease in intracapillary colloid oncotic pressure (COP) or increase in capillary permeability should result in increased interstitial fluid. Iso-oncotic increase in pulmonary artery wedge (PAW) causes pulmonary dysfunction. Isobaric reduction of COP with normal capillary permeability does not result in pulmonary interstitial edema. Because sepsis is a frequent antecedent of clinical pulmonary dysfunction, the question was asked: does reduction in the COP-PAW gradient in the presence of sepsis result in increased pulmonary dysfunction? Twenty baboons were studied: group 1--control, group 2--4-h constant infusion of E. coli, group 3--plasmapheresis alone, group 4--plasmapheresis followed by sepsis. Ringer's lactate was infused to keep PAW constant. Arterial and mixed venous blood gases were drawn and the intrapulmonary shunt (QS/QT) was calculated. The data were compared using Tukey's HSD test and one way analysis of variance. Plasmapheresis alone resulted in a 68% reduction in COP (15 +/- 2.9 (SD) torr to 4.6 +/- 0.6 in group 3 and 16.5 +/- 4.3 to 5.7 +/- 0.9 in group 4, p less than 0.05). Sepsis resulted in an increase in QS/QT in all septic animals. There was no increased QS/QT in those animals that had sepsis added to plasmapheresis, group 4 (p less than 0.05). These data indicate that sepsis leads to pulmonary dysfunction but that this dysfunction appears to be independent of colloid oncotic forces.

Animals↗
PubMed1978

Central venous pressure or pulmonary capillary wedge pressure as the determinant of fluid replacement in aortic surgery.

Both central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) have been used as guides to fluid replacement in patients undergoing abdominal aortic surgery. To test the hypothesis that changes in PCWP (deltaPCWP) may be reliably estimated from changes in CVP (deltaCVP), 55 patients had simultaneous measurements (302 paired observations) of CVP and PCWP, as well as of cardiac output, before and during operation. The correlation between deltaCVP and deltaPCWP was high (r = 0.716, P less than 0.001). The estimated slope for the linear regression was 0.88. The standard error of the estimate was +/- 3.75 torr, making the prediction of deltaPCWP from deltaCVP accurate only to within 7.5 torr. There were five patients who each had a low and failing CVP accompanied by a stable cardiac output and a rising PCWP; for them, a decision to administer fluid based on the CVP might have resulted in pulmonary edema. Although deltaCVP accurately predicted direction and magnitude of deltaPCWP in the majority of patients (90%), there was a small group in whom there was no substitute for direct measurement of PCWP.

Adult↗