The Quantitative Evaluation Of Carbon Dioxide Absorption During Laparoscopic Cholecystectomy

Objective:With the wide application of laparoscopic technique,the various pathophysiological changes caused by carbon dioxide pneumoperitoneum have attracted the attention of many researchers.At present,it is known that carbon dioxide pneumoperitoneum has different effects on respiratory and circulation in laparoscopic surgery,carbon dioxide pneumoperitoneum for a long time leads to hypercapnia,which may be related to carbon dioxide absorption.However,the research on carbon dioxide absorption at home and abroad is limited to qualitative analysis.Therefore,this study investigate metabolic parameters of patients before and after carbon dioxide pneumoperitoneum,which realized quantitative evaluation on carbon dioxide absorption during laparoscopic cholecystectomy.The purpose is reducing the risk of surgery,improving the safety of laparoscopic surgery.Methods:30 patients with laparoscopic cholecystectomy,scheduled as ASA I or II.The anesthesia method was selected by balance anesthesia,using the improved fast induced anesthesia induction: Midazolam 0.02mg/kg,Fentanyl 3-4?g/kg,Propofol 2-2.5mg/kg and Rocuronium 0.6mg/kg.Endotracheal intubation was performed after complete muscle relaxation and stable circulation,adjusting inspiratory-to-expiratory ratio of 1:2.The gas inhalation is the mixture of air and oxygen,among which the oxygen concentration was 50%.Regulate the tidal volume as 8-10ml/kg,respiratory rate as 10-14 times/min.And we should adjust the tidal volume and respiratory rate during the surgery,to keep end-tidal carbon dioxide 40 mmHg.Also we should maintain the pneumoperitoneum pressure as 12 mmHg,and gas-flow rate 2L/min.During the surgery,we investigate following parameters:(1)Basic vital signs: HR?MAP?SpO2.(2)Metabolic parameters: PetCO2?VO2?VCO2?RQ.Record the above indicators before(T0)and 10min(T1)?20min(T2)?30min(T3)?40min(T4)after carbon dioxide pneumoperitoneum,then calculate the carbon dioxide absorption.SPSS 22.0 statistical analysis system was used to collect the data for statistical analysis,and the comparison between groups was done by T test.According to the time and the carbon dioxide absorption,we can draw the regression curve,and calculate the regression equation,and then carry out the correlation test,P < 0.05 has statistical significance.Results:(1)Basic vital signs: There was no significant difference in SpO2 before and after carbon dioxide pneumoperitoneum(P>0.05).HR was significantly accelerated in the early stage of carbon dioxide pneumoperitoneum(T1?T2)(P < 0.05),and the latter(T3?T4)was not significantly accelerated(P > 0.05);MAP was significantly increased before and after carbon dioxide pneumoperitoneum(P < 0.05).(2)Metabolic parameters: VO2,VCO2 and carbon dioxide absorption increased significantly before and after carbon dioxide pneumoperitoneum(P < 0.05).Moreover,the absorption of carbon dioxide was correlated with the prolongation of pneumoperitoneum time,and the regression equation is Y?=14.26+1.238 X.Conclusion:(1)The results showed that there was a significant increase in circulatory function of patients during laparoscopic surgery.(2)At the same time,carbon dioxide pneumoperitoneum can significantly increase the absorption of carbon dioxide.As a result,using the regression equation,the amount of carbon dioxide absorbed can be estimated based on the time of laparoscopic surgery to assess the risk of surgery and ensure safety.