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 > or = 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.