Platelet activating factor mediates cardiopulmonary dysfunction during graded bacteremic shock
Woolley, D.S.; Puglisi, R.N.; Quinn, J.V.; Slotman, G.J.
Journal of Trauma 41(2): 291-6; Discussion 296-7
1996
ISSN/ISBN: 0022-5282 PMID: 8760539 Document Number: 461297
Objective: To determine whether or not platelet activating factor (PAF) is a necessary mediator of cardiovascular dysfunction during graded bacteremia, and to identify PAF interactions with eicosanoids and tumor necrosis factor-alpha (TNF-alpha). Methods: Seventeen anesthetized, hemodynamically monitored adult swine were studied for 4 hours in three groups. Group 1 (ANES, n = 5) were anesthesia controls; group 2 (septic control, SC, n = 6) received intravenous Aeromonas hydrophila (109/mL) at rates incrementally increased from 0.2 to 4.0 mL/kg/h; group 3 (WEB, n = 6) received the PAF receptor antagonist WEB 2086, 3.0 mg/kg intravenously, then A. hydrophila. Cardiopulmonary parameters and plasma thromboxane B-2 (TXB-2), prostaglandin 6-keto F-1-alpha (PGI-2), leukotriene B-4 (LTB-4), leukotrienes C-4D-4E-4 (LTC-4D-4E-4), and TNF-alpha were measured hourly. Statistical analysis was carried out using two-way analysis of variance (ANOVA) for repeated measurements, Dunnett's t test, and Student's t test, where appropriate. Statistical significance was determined at the 95% confidence interval. Values are presented as the mean +- SEM. Results: Pulmonary arterial pressure, pulmonary capillary wedge pressure, central venous pressure heart rate, VO-2 and O-2ER decreased significantly after WEB 2086 infusion, compared with SC, and mean arterial pressure, systemic vascular resistance index, stroke volume index, and left ventricular stroke work index increased. Arterial pH decreased significantly in SC animals, but was maintained at normal levels during bacteremia in the WEB group. Differences between WEB and SC for cardiac index, pulmonary vascular resistance index, right ventricular stroke work index, PaO-2, SaO-2, and PCO-2, were not significant. The addition of WEB 2086 significantly decreased plasma levels of TXB-2, PGI-2, LTB-4, and TNF-alpha compared with the SC group. LTC-4D-4E-4 was decreased in WEB compared with SC animals, in which LTC-4D-4E-4 increased during graded bacteremia. Conclusions: PAF is necessary to the development of systemic vasodilation and hypotension, pulmonary hypertension, decreased stroke volume, metabolic acidosis, and increased oxygen uptake during graded bacteremia. PAF-induced eicosanoid and cytokine release may be involved.