Extensive subcutaneous emphysema and hypercapnia during laparoscopic cholecystectomy: two case reports.

We report two cases of marked hypercapnia of more than 60 mm Hg (PaCO2) and extensive subcutaneous emphysema noted during laparoscopic cholecystectomy. The first case, a 55-year-old man was diagnosed as having cholecystolithiasis and had hypercapnia up to 83.5 mm Hg (PaCO2) during laparoscopic cholecystectomy. The patient resumed spontaneous respiration under controlled ventilation accompanied by persistent bigeminal pulse. Soon after deflation, CO2 returned to normal range, and extensive subcutaneous emphysema was detected in the recovery room. The second patient, a 53-year-old woman, had cholecystolithiasis and also underwent laparoscopic cholecystectomy. Both hypercapnia rising to 61.1 mm Hg (PaCO2) and extensive subcutaneous emphysema appeared just before completion of resection of the gallbladder. Mild hypercapnia during pneumoperitoneum of about 50 mm Hg (PaCO2) has been reported previously. As compared with cases in the literature, the present cases suggest that hypercapnia is due to extensive subcutaneous emphysema. The large absorption surface area in the subcutaneous tissue and the large difference in the partial pressure cause the extensive gaseous interchange of CO2 between subcutaneous tissue and blood perfusing into it at the moment between peritoneal cavity and blood perfused the peritoneum.