A method to attenuate pneumoperitoneum-induced reductions in splanchnic blood flow

Abstract

Objective: To determine if increasing nitric oxide bioactivity by inclusion of ethyl nitrite (ENO) in the insufflation admixture would attenuate pneumoperitoneum-induced decreases in splanchnic perfusion.

Summary background data: Organ blood flow is reduced during pneumoperitoneum and can contribute to laparoscopy-associated morbidity and mortality. Previous attempts to control such decreases in flow have been ineffective.

Methods: Laser-Doppler flow probes were placed on the liver and right kidney of anesthetized pigs. After a baseline recording period, animals were insufflated to a final intraperitoneal pressure of 15 mm Hg. Group one received CO2 (standard practice), whereas group 2 received CO2 plus 100 ppm ENO. Insufflation was maintained for 60 minutes and then the abdomen was manually deflated; monitoring was continued for another 60 minutes.

Results: CO2 insufflation (n = 5) cut liver blood flow in half; liver flow remained at this level throughout the postinsufflation period. Inclusion of 100 ppm ENO (n = 6) attenuated both the acute and prolonged blood flow decreases. Statistical modeling of the data showed that, on average, liver blood flow was 14.3 U/min higher in the ENO pigs compared with the CO2 group (P = 0.0454). In contrast, neither treatment significantly altered kidney blood flow (P = 0.6215).

Conclusion: The data indicate that ENO can effectively attenuate pneumoperitoneum-induced blood flow decreases within the peritoneal cavity. The result suggests a novel therapeutic method of regulating hemodynamic changes during laparoscopic procedures.

FIGURE 1. Time course of heart rate and mean arterial pressure changes during the ethyl nitrite (ENO) dose-response study. The abdomen was kept at a pressure of 15 mm Hg during insufflation with CO₂ and the serial increases in the concentration of ENO. Data are expressed as mean ± standard deviation values (n = 3).

FIGURE 2. Time course of heart rate and liver and kidney blood flow during and after insufflation with CO₂ (n = 5) or CO₂ plus 100 ppm ethyl nitrite (ENO) (n = 6). Intraabdominal pressure was kept at 15 mm Hg during the 60-minute period of insufflation (hatched box). At the 60-minute mark, the abdomen was manually deflated. Data are expressed as mean ± standard deviation values. Liver blood flow in the CO₂/ENO group was significantly higher than the CO₂ alone group (P = 0.0454). There was no group difference in kidney blood flow (P = 0.6215).