Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
Endotoxemia and sytemic inflammation are common findings during and after cardiopulmonary bypass (CPB) . The relationship of CPB duration and endotoxemia as well as proinflammatory cytokines are controversially discussed [2,3]. This study examines the relationship of endotoxemia, proinflammatory cytokines and acute phase proteins to the duration of CPB and aortic cross clamp (X-clamp).
METHODS: After IRB approval and informed consent had been obtained 20 patients with a left ventricular ejection fraction >or=to 0.5, who underwent elective coronary bypass grafting, were studied in a consecutive sample. CBP was performed with mild hypothermia (30-34[degree sign] C), with non-pulsatile flow and a pump flow rate of 2.4 liter min-1 m-2. Patients were instrumented with a radial and pulmonary artery catheter. Additionally, an oximetric balloon catheter was inserted in the right hepatic vein guided by fluoroscopy. After induction of anesthesia, baseline values were obtained and 20 min after onset of CPB, 20 min after termination of CPB, at admission on the intensive care unit (ICU) and 6, 8, 12 and 24 hours later mixed and hepatic venous concentrations of endotoxin, interleukin-6 (IL-6), C-reactive protein (CRP) and serum amyloid A (SAA) as well as splanchnic oxygen extraction were determined. Concentration peaks at 6 h (endotoxin, IL-6) and 24 h (SAA, CRP) after the surgical procedure were used for correlations with CPB duration and X-Clamp time. Statistical evaluation was performed with Friedman and Wilcoxon test and Pearson's correlation coefficient.
RESULTS: There were significant positive correlations between CPB duration and X-clamp time, and mixed and hepatic venous concentrations of endotoxin, IL-6 and SAA. However, mixed and hepatic venous concentrations of CRP did not correlate to CBP duration and X-clamp time (Table 1).
Splanchnic oxygen extraction increased during (39,8 +/- 12.2%) and 20 min after CPB (32.4 +/- 15.2%) compared to baseline values (26.0 +/- 6,2%), and declined thereafter (p < 0.05). Systemic oxygen extraction, by contrast, did not change during the entire study period (p < 0.05).
DISCUSSION: Regarding the controversial preexisting findings these results support the hypothesis that the duration of CPB as well as X-clamp time influence endotoxemia, the release of proinflammatory cytokines and acute phase proteins. The extent of endotoxemia and its relationship to CBP-duration and X-clamp time is most likely induced by selective splanchnic hypoperfusion.
1. JAMA 1996; 275: 1007-1012
2. J Thorac Cardiovasc Surg 1994; 108: 636-641
3. Crit Care Med 1993; 21: 1684-1691