Transcutaneous PCO2 monitoring during laparoscopic cholecystectomy in pregnancy

Abstract

Purpose: Respiratory acidosis during carbon dioxide (CO2) insufflation has been suggested as a cause of spontaneous abortion and preterm labour following laparoscopic cholecystectomy during pregnancy. Capnography may not be adequate as a guide to adjust pulmonary ventilation during laparoscopic surgery and hence arterial carbon dioxide (PaCO2) monitoring has been recommended. We report the feasibility and benefits of transcutaneous carbon dioxide monitoring (PtcCO2) as an approach to optimise ventilation during laparoscopic surgery in pregnancy, Method: A healthy parturient received general anaesthesia for laparoscopic cholecystectomy. Pulmonary ventilation was adjusted to maintain end-tidal carbon dioxide (conventional P(ET)CO2) at 32 mmHg during CO2 insufflation. A PtcCO2 monitor was used to trend PaCO2 throughout the procedure. Mechanical ventilation was interrupted every five minutes to obtain an end-tidal PCO2 value at large tidal volume (squeeze P(ET)CO2). Results: The PtcCO2 increased from 39 mmHg before induction to 45 mmHg after CO2 insufflation. This corresponds to an estimated maximum PaCO2 of 39-40 mmHg during insufflation. The PtcCO2 gradually returned to pre- induction baseline values one hour after the termination of CO2 insufflation, Squeeze P(ET)CO2 values approximated PtcCO2 more closely than did conventional P(ET)CO2 values (P < 0.01). Conclusion: Continuous PtcCO2 measurements as well as squeeze P(ET)CO2 may be of clinical value in trending and preventing hypercarbia during laparoscopic surgery.