Effects Of CO₂Insufflation On Respiratory, Circulation And Body Temperature During Tansperitoneal And Retroperitoneal Laparoscopic Nephrectomy

ObjectiveTo observe the effects of CO2insufflation on respiratory, circulation, and body temperature during transperitoneal laparoscopic nephrectomy(TLN) and retroperitoneal laparoscopic nephrectomy (RLN).MethodsFifty patients, scheduled for laparoscopic nephrectomy, ASA grade Ⅰ-Ⅱ, were assigned to two groups (n=25, each):T group received TLN and R group given RLN. Midazolam, etomidate, atracurium and fentanyl were given for anesthetic induction, LMA laryngealmasks were used for tracheal intubation, sevoflurane continuingly and atracurium, fentanyl intermittently for anesthetic maintenance. The respiratory data were kept at VT8—10ml/kg, respiratory frequency14-16bpm and a total fresh gas flow (FGF) of1L/min. The patients general information, including gender, age, body surface area, body-mass index (BMI), operation lasting time, hemorrhage volumes, extubation time, mental conditions, visual analog scale (VAS) score, as well as postoperative conditions, adverse reactions, hospital stay were observed perioperatively. The end-tidal CO2(ETCO2), heart rate (HR), mean arterial blood pressure (MAP) and body temperature (Tc for nasopharyngeal temperature, Ta for forearm temperature, and Tf for fingertip temperature) were recorded respectively at the following time intervals:5min before CO2insufflation (T0),15min (T1),30min (T2),45min (T3),60min (T4),75min (T5),90min (T6) after CO2insufflation, without CO2insufflation (T7),5min postoperation (T8),5min after tracheal extubation (T81). Blood-gas parameters were also recorded at T0, T2, T4, T6and T8’. Forearm-fingertip gradients (Grada-f) was evaluated by using Ta minusTf.Results1. General informationThere was no statistical difference in gender, age, BMI, body surface area, operation time, extubation time, amount of bleeding, urinary volume, transfusion volume, adverse reactions (shivering, nausea and vomiting), visual analog score (VAS), volume of drainage, exhaust time, walking time and the length of stay.2. Changes in respiratory systemETCO2increased quickly at the first15min during CO2insufflation in both groups, then gradually reached a plateau. All parameters during CO2insufflation period were statistically significant from baseline level (P<0.05). After release of the pneumoperitoneum, ETCO2immediately decreased and closed to the initial level at the time point of TO (P>0.05).PH and BE values decreased, while PaCO2increased synchronously. Compared with the data collected before operation, the parameters of blood gas in operation were significantly different(P<0.05); even5min after extubation, the parameters returned a bit, but the mean values still have a big difference to the baseline level (P<0.05).Moreover, the values of ETCO2in the two groups were significantly different60min after the establishment of pneumoperitoneum (P<0.05). In addition, PaCO2appeared to be statistically different between the groups at the time point of T4and T6(P<0.05), and the PH value also became significantly different at T6(P<0.05). 3. Changes in circulatory systemThe HR values changed smoothly during the operation, only a mild increase could be seen when started to insufflate CO2gas. The variabilities in the surgery were not significant in comparison to the baseline level, the only exception happened after extubation when the patients already woke up. In T group, MAP values experienced great changes after CO2insufflation and became significantly maintained all along the whole surgery. The R group, however, showed a relatively mild change with regard to arterial blood pressure. After60minutes’ CO2insufflation, the parameters of MAP in R group were statistically different to the baseline level. Both HR and MAP values were not significantly different between the groups (P>0.05), but the mean value of MAP appeared significantly higher in T group than that in R group30min after CO2sufflation (P<0.05).4. Changes in body temperatureTc decreased rapidly in the first60min after CO2insufflation, and then the declining tendency slowed down in both groups. In T group, a significant difference compared with the baseline level appeared only after15min CO2insufflation, while in R group, the time-consuming lengthened to45min. At the end of the surgery, Tc values of the two groups were above36℃. Grada.f collected at15min after the establishment of pneumoperitoneum were statistically different from baseline level in both groups, with the prolonging of the procedure, the gradients increased gradually from negative to positive. The variation of absolute values from the R group was larger than that in the T group, but no significant difference has been found between the two groups (P>0.05), as to Tc and Grada-f.Conclusions:CO2insufflation has no obviously harmful influences on respiratory, circulation and body temperature during tansperitoneal and retroperitoneal laparoscopic nephrectomy.