Influence of carbon dioxide on respiratory function during posterior retroperitoneoscopic adrenalectomy in prone position.

Objective: To evaluate the influences of CO2 insufflation on changes in blood gas analysis and end tidal CO2 tension (PetCO(2)) during posterior retroperitoneoscopic adrenalectomy in the prone position. Methods: Arterial blood gas analysis and measurements of PetCO2 were carried out during CO2 insufflation in 16 patients who underwent posterior retroperitoneoscopic adrenalectomy in the prone position (PRA group). The results were compared to 10 patients who underwent open posterior adrenalectomy (OPA group). Ventilation was artificially controlled during the study period in all cases. Results: Arterial pH, PaCO2, PetCO(2) and PaO2 were not significantly different between the PRA and OPA groups, However, the PaCO2-PetCO(2) gradient in the PRA group was significantly higher than that in the OPA group (p < 0.01). Conclusion: Transperitoneal absorption of CO2 occurs in patients undergoing retroperitoneoscopy in the prone position, The alveolo-arterial CO2 gradient may be the only parameter which indicates the absorption of CO2 during PRA.