Retroperitoneal and Intraperitoneal CO2Insufflation Have Markedly Different Cardiovascular Effects

Abstract Both retroperitoneoscopic and laparoscopic surgical approaches to kidney and adrenal gland have been reported but their cardiopulmonary pathophysiology has been incompletely characterized. To test the hypothesis that these approaches have markedly different impact on the circulatory and respiratory systems, we assessed at similar insufflation pressures alterations in cardiovascular and respiratory variables during retroperitoneal and intraperitoneal CO 2 insufflation. Eighteen healthy, anesthetized (propofol, alfentanil, vecuronium), mechanically ventilated pigs were randomly instrumented for either retroperitoneoscopic ( n = 9) or laparoscopic ( n = 9) surgery. After CO 2 insufflation cardiovascular and respiratory variables were measured at four cavity pressures (baseline, 10, 15, and 20 mmHg), while end-expiratory CO 2 tension was maintained by adjusting tidal volume. Data were analyzed for both insufflation-pressure-dependent and group effects by one-way and two-way ANOVA for repeated measurements, respectively, followed by Newman–Keuls post hoc test ( P P P P P 2 insufflation. Most important, intraperitoneal unlike retroperitoneal insufflation induced a marked inferior vena caval pressure gradient (8.9 ± 1.1 mmHg vs 1.0 ± 0.5 mmHg, P 2 insufflation required increased tidal volumes to adjust end-tidal CO 2 tension to baseline, intraperitoneal CO 2 insufflation resulted in a significantly greater increase of mixed venous and arterial carbon dioxide tensions ( P P = 0.018) were required with intraperitoneal than with retroperitoneal insufflation to administer the same tidal volume, indicating a greater decrease in quasi-static compliance with intraperitoneal insufflation ( P = 0.0436). Thus, (i) cardiovascular and respiratory changes are much less during retroperitoneal than intraperitoneal CO 2 insufflation, even at the same insufflation pressures, and (ii) retroperitoneal CO 2 insufflation unlike intraabdominal CO 2 insufflation does not induce an inferior vena caval pressure gradient and hence does not appear to impair systemic lower body venous return up to insufflation pressures of 20 mmHg.