The effect of insufflation pressure on CO(2) pneumoperitoneum and embolism in piglets

Abstract

We conducted this study to investigate the effect of insufflation pressure on the pathophysiology of CO(2) pneumoperitoneum and embolism in an infant model. Twenty anesthetized piglets had stepwise intraperitoneal insufflation with CO(2) for 15 min at pressures ranging from 5 to 20 mm Hg. The piglets were ventilated to baseline normocarbia (ETCO(2) = 30 mm Hg, PaCO(2) = 38 mm Hg) before beginning each insufflation. CO(2) was then insufflated IV in 15 of these piglets at the same pressures. There was no reduction of blood pressure or cardiac output with intraperitoneal insufflation, but the stroke volume declined significantly (*P < 0.05) from (mean +/- SE) 10.6 +/- 1.3 mL to 8.5 +/- 1.3* mL and from 10.0 +/- 1.4 mL to 7.2 +/- 1.2* mL at 15 and 20 mm Hg insufflation pressure, respectively. Abdominal insufflation at 5, 10, 15, and 20 mm Hg caused an increase in ETCO(2) to 31.7 +/- 0.8 mm Hg, 35.6 +/- 1.2* mm Hg, 37.5 +/- 1.5* mm Hg, and 40.1 +/- 1.8* mm Hg and in PaCO(2) to 41.1 +/- 1.3* mm Hg, 44.2 +/- 1.4* mm Hg, 49.9 +/- 1.8* mm Hg, and 53.0 +/- 2.1* mm Hg, respectively. In contrast, the ETCO(2)decreased to 19.4 +/- 1.5* mm Hg, 20.4 +/- 1.4 mm Hg, 15.2 +/- 2.1* mm Hg, and 10.6 +/- 2.0* mm Hg with IV insufflation using the same pressures. IV insufflation caused marked hypotension and mortality. As the insufflation pressure increased, the mortality increased (0 in 15, 1 in 15, 1 in 14, and 6 in 13* at 5, 10, 15, and 20 mm Hg; *P < 0.05 vs 0 in 15, 1 in 15, and 1 in 14). This study suggests that although intraperitoneal insufflation up to 20 mm Hg may be tolerated hemodynamically, the lowest possible pressure should be used to reduce hypercarbia. A low insufflation pressure may also prevent mortality from CO(2) embolism.

Implications: The lowest pressure possible should be used when inflating the abdomen with CO(2) to perform a laparoscopy in babies. A low pressure allows better ventilation and may prevent mortality if CO(2) is accidentally injected into a vein.