Comparative Analysis Of Acid-base Alterations Between Laparoscopic Gastric Cancer Surgery And Laparotomy

Objective:Carbon dioxide insufflation and desufflation during laparoscopic surgery result in an acid-base imbalance. The purpose of this study was to use Peter· Stewart’s approach to investigate the effect of pneumoperitoneum on the acid-base status, and compared with laparotomy.Methods:Selecting one hundred patients who required surgical treatment in the provincial hospital affiliated to shandong university. One hundred patients undergoing gastrointestinal surgery were randomly assigned to the laparoscopy group (n=50) or the laparotomy group (n=50). The acid-base parameters were measured10min after the anesthesia induction (T1),1hour after opening the peritoneum or pneumoperitoneum according to the group (T2), the end of the surgery (T3), and1hour after the surgery (T4). Finally, sorting out the data,Establishing a database and using the SPSS19.0statistical software for data statistics analysis. One-sample Kolmogorov-Smirnov test is used to test the distribution of all measures and calculate data. Patients’characteristics were tested by Mann-Whitney U-test or Fisher’s exact test when appropriate. And the data within the group of other variables were analysed with ANOVA. T-test was performed to compare intergroup differences. A value of P<0.05was considered statistically significant.Results:There was no significant difference between the two groups in terms of age,weight,sex,medical history (hypertension/DM), operation time, pneumoperitoneum time,operation(Billroth Ⅰ and Billroth Ⅱ), fluid balance intraoperative, fluid balance postoperative1h, urine output intraoperative,estimated blood loss. And there were no significant differences in the base excess of interstitial fluid (BEecf), strong ion gap, or anion gap between the two groups. In both groups, the BEecf decreased at T2, T3and T4compared with baseline value. At T2in the laparoscopy group, the pH was decreased whereas PaCO2was increased compared with their baseline values, but at T4, pH promptly returned to a normal value after the desufflation. In the laparotomy group, at T3and T4the apparent strong ion difference (SIDa) and pH were decreased whereas the lactate and chloride were increased compared with their baseline values.Conclusions:The decrease in the pH during the pneumoperitoneum was affected by the increase in PaCO2, which quickly returned to a normal value after the desufflation. We can say, during the laparoscopic surgery, breathing is an important factor which can lead to the decrease of pH values. On the other hand, the decrease in the pH after laparotomy was affected by the metabolic factors, which persisted an hour after the surgery. The decrease in the pH and SIDa with elevated lactate was observed after laparotomy in the laparotomy group but not after laparoscopic surgery. At T3and T4in the laparotomy group, lactic acid is significantly elevated, suggesting that hypoperfusion and accumulation of lactic acid after laparotomy.