The detection of carbon dioxide embolism during laparoscopy in pigs: A comparison of transesophageal Doppler and end-tidal carbon dioxide monitoring

Background: The aim of the study was to compare the value of transesophageal Doppler and end-tidal carbon dioxide monitoring to detect venous carbon dioxide embolism in pigs during laparoscopic cholecystectomy. Method: Ten pigs were anesthetized under constant ventilation, and instrumented for laparoscopic cholecystectomy. CO2 pneumoperitoneum was performed at 15 mmHg and then, successive increased intravenous gas boluses of 0.1 to 4 ml/kg injected through the femoral vein using a 55-mm long catheter. The responses indicative of embolism were defined as: 1) a change in Doppler tone placed facing the junction of the right atrium and inferior vena cava; 2) a change in end-tidal CO2 greater than or equal to 0.4 kPa. Results: Doppler was more sensitive in detecting 0.1, 0.2 and 0.4 ml/mg of CO2 embolism than end-tidal CO2 (P<0.05). Over 0.4 ml/mg no differences in sensitivity were found but the Doppler signal modifications occurred earlier than the changes in end-tidal CO2. Moreover, these changes always consisted of a reduction of the value. Conclusion: During laparoscopic cholecystectomy in pigs, transesophageal Doppler was a highly sensitive monitor which provided an earlier detection of CO2 embolism and at lower doses than end-tidal CO2 monitoring. (C) Acta Anaesthesiologica Scandinavica 41 (1997).