Carbon Dioxide Absorption During Different Laparoscopic Surgery

Objective To compare carbon dioxide absorption during different laparoscopic surgerys with different CO2 insufflated cavities.Methods Forty ASAⅠorⅡpatients aged 30～60 yrs undergoing elective laparoscopic surgery utilizing CO2 insufflation were studied. They were divided into four groups according to different laparoscopic surgerys : the first (groupⅠ, n=10 ) had endoscopic thyroidectomy with subcutaneous CO2 insufflation, the second (groupⅡ, n=10) had laparoscopic hepatectomy with CO2 pneumoperitoneum, the third (groupⅢ, n=10 ) had laparoscopic hysterectomy with CO2 pneumoperitoneum and Trendelenburg position and the fourth (groupⅣ, n=10) had laparoscopic total extraperitoneal hernia repair with a cavity formed in the preperitoneal tissue and insufflated CO2. All patients received intravenous inhalational anesthesia with endotracheal intubation under unified standard. After orotracheal intubation, the lungs of all patients were ventilated with intermittent positive pressure ventilation(IPPV),tidal volume of 10 ml·kg -1, respiratory rate of 12 per minute, fraction of inspired oxygen 50% and 50mmHg by adjusting respiratory rate. HR, NBP, SpO2, PetCO2, Ppeak, pH, PaO2 and PaCO2was measured and Pa-etCO2, VCO2 was calculated 10min after intubation ( before CO2 insufflation, t1), 10min (t2), 30min(t3), 60min(t4) during CO2 insufflation and 15min (t5) after desufflation. The extent and severity of subcutaneous emphysema and the time of extubation was recorded.Results The 4 groups were comparable with respect to general state date (age and weight), SpO2and PaO2. As compared with the values at t1, HR, PetCO2, PaCO2, Pa-etCO2, VCO2 at t2-4 and SBP, DBP, MAP at t2 were significantly increased while PH was significantly decreased at t2-4 in the 4 groups, Ppeak was significantly increased at t4 and t5 in groupⅠand at t2-4 in groupⅡ,ⅢandⅣ. At t2-4 in groupⅣ, PetCO2 was significantly higher than in groupⅡandⅢ, PaCO2, VCO2, Pa-etCO2 was significantly higher than in the other 3 groups while PH was significantly lower than in the other 3 groups. PetCO2, PaCO2, VCO2 of most patients were significantly higher at t5 than at t1. All laparoscopic surgerys were over successfully. Some patients in the 4 groups suffered from different extent and severity subcutaneous emphysema. There was no significant difference in the time of extubation among the 4 groups.Conclusions Preperitoneal carbon dioxide insufflation causes more carbon dioxide absorption than pneumoperitoneum and subcutaneous insufflation. Foot-high horizontal position impairs respiratory function. The subcutaneous emphysema and CO2 remained in surgery cavity are mainly responsible for continual carbon dioxide absorption after desufflation. Permissive hypercapnia is safe for patients undergoing laparoscopic surgery. Proper anesthetic managements ensure safety of laparoscopic surgery.