Aim of the Study: To compare efficacy of the Circle absorption system and the Bain breathing system in containing  hypercarbia by ETCO₂modulation with the help of capnographic monitoring, during laparoscopic cholecystectomy with carbon dioxide pneumoperitonium.

Materials and Methods: Fifty adult patients of ASA–I or II physical status undergoing laparoscopiccholecystectomy under general anesthesia were allocated into two groups. Ingroup A the Circle absorption system and in group B the Bain breathing system was used for delivery of the anesthetics and performance of IPPV. Same drugs and anaesthetic technique excepting the breathing system with variable Fresh Gas Flow (FGF)as per group were used.

Results and Observations:ETCO₂variables in both the systems were found to be homogenous.The Bain system differed significantly with regard to rebreathing characteristics signified by higher FiCO2.

Conclusion:Apart from the variation of fresh gas flow boththe systems are equally effective in terms of Carbon dioxide elimination and both can be effectively used for maintaining optimal CO₂ level during laparoscopic cholecystectomy with carbon dioxide pneumoperitonium.