Carbon dioxide absorption during laparoscopic pelvic operation

Several factors may influence the degree of carbon dioxide (CO2) absorption during laparoscopy. Hypercapnia as a result of excessive CO2 absorption may have adverse clinical effects.

To identify factors associated with increased CO2 absorption, we retrospectively calculated the CO2 elimination in 65 adult patients who underwent operative pelvic laparoscopy. Increases in CO2 elimination were assumed to be indicative of CO2 absorption. The most commonly performed procedures were bladder neck suspension and pelvic lymphadenectomy. The median insufflation time was 165 minutes. An extraperitoneal approach was taken in 32 percent of the patients.

Of patients evaluated with postoperative roentgenograms of the chest, 35 percent had subcutaneous emphysema and 9 percent had pneumomediastinum with or without pneumothorax. Multiple factorial analysis of the variance revealed that the extraperitoneal approach, development of subcutaneous emphysema, and increased duration of insufflation were independently associated with a greater increase in peak CO2 elimination. Insufflation time and subcutaneous emphysema had stronger effects in the extraperitoneal group.

The risk factors for hypercapnia can be identified. Careful consideration of the patient's ability to tolerate hypercapnia should be made when planning extraperitoneal laparoscopy, especially if the procedure is likely to be prolonged. The clinical development of subcutaneous emphysema should alert the surgeon to the possibility of subsequent hypercapnia.