CAN PULSE OXIMETRY AND END-TIDAL CAPNOGRAPHY REFLECT ARTERIAL OXYGENATION AND CARBON-DIOXIDE ELIMINATION DURING LAPAROSCOPIC CHOLECYSTECTOMY

An investigation was carried out on 13 ASA class 1 or 2 adult patients undergoing laparoscopic cholecystectomy. Throughout laparoscopy, the end-tidal PCO2 was continuously monitored by capnography and the arter ial hemoglobin oxygen saturation by pulse oximetry. Also, repeated mea surements of arterial blood gases were done. Ventilation was controlle d using an inspired oxygen concentration of 33% and tidal volume of 10 to 15 ml/kg at a rate of 10-14/min. The report showed that both the m ean end-tidal PCO2 and arterial PCO2 progressively increased following carbon dioxide insufflation, to reach a maximal value after 30 min, w ith no significant change in the arterial-alveolar PCO2 gradient. Also , the arterial PO2 significantly decreased, and the hemoglobin oxygen saturation was always above 98% whether monitored by arterial blood ga s analysis or by pulse oximetry. The results suggest that end-tidal ca pnography and pulse oximetry can be used as noninvasive techniques for monitoring arterial oxygenation and carbon dioxide elimination during laparoscopic cholecystectomy.