Transcutaneous CO2/O-2 and CO2/air suction in patients undergoing cataractsurgery with retrobulbar anaesthesia

We investigated transcutaneous partial CO2 and O-2 pressures and respirator y rate in unpremedicated elderly patients of ASA physical status 1 to 3 who underwent cataract surgery under retrobulbar anaesthesia. In group A no ai r suction was used. In group B suction was applied under the sterile drapes to avoid rebreathing of CO2. In group A transcutaneous partial CO2 pressur e and respiratory rate significantly increased compared with baseline, wher eas in group B they remained constant. In both groups transcutaneous partia l O-2 pressure and oxygen saturation as measured by pulse oximetry signific antly rose after insufflating oxygen 31.min(-1). Heart rate and mean arteri al blood pressure remained constant. Our results demonstrate that the appli cation of suction near the patient's head prevents CO2 rebreathing and subs equent hypercapnia associated with an elevated respiratory rate. The use of suction makes it unnecessary to raise oxygen administration. Suction combi ned with monitoring of partial CO2 pressure using transcutaneous sensors sh ould be used in all ophthalmological operations under retrobulbar anaesthes ia.