Recruitment Maneuver With Different Inspired Oxygen Concentrations On Perioperative Respiratory Function In Patients Undergoing Laparoscopic Gastrointestinal Surgery

Objective:Observing the effects of PEEP increasing inhalation oxygen concentration on lung oxygenation,lung compliance,diaphragmatic mobility and thickness during laparoscopic gastrointestinal surgery,aiming to provide some ideas and basis for clinical selection of more beneficial lung oxygenation concentration and optimization of lung protective ventilation strategies in laparoscopic gastrointestinal surgery.Methods:Patients who underwent laparoscopic gastrointestinal surgery at Yixing Hospital Affiliated to Jiangsu University and Wuxi Second People’s Hospital from January 2022 to April 2023 and met the inclusion and exclusion criteria were randomly divided into Fi O₂80%lung recruitment group（Group A）,Fi O₂30%lung recruitment group（Group B）,and control group（Group C）using a random number table method.Groups A and B underwent their first lung recruitment after the establishment of pneumoperitoneum,Afterwards,use the PEEP incremental method for lung recruitment once every hour,and perform lung recruitment again after surgery（at the end of the suture）;Group C did not undergo lung recruitment throughout the entire process.A total of90 patients were included in the study,with 30 patients in each group.All patients underwent intravenous inhalation combined with general anesthesia.During the surgery,except for the process of lung recruitment,mechanical ventilation was performed in Capacity Control Ventilation（VCV）mode at all other times.The parameter setting was fresh gas inhalation flow rate of 1.5 L/min;Fi O₂50%;Tidal volume 6-8 ml/kg;Respiratory rate 12 bpm;Breath in ratio1:2;PEEP5 cm H2O.Observe and record three groups of patient related indicators:In this study,oxygenation index（OI）was used as the main observation indicator,and secondary observation indicators were set around respiratory mechanics and diaphragm function,two factors that affect oxygenation index.Specifically:（1）Basic data:preoperative and intraoperative data of the patient:age,gender,body mass index（BMI）,ASA grade,surgical time,pneumoperitoneum time,intraoperative fluid replacement volume,blood loss,and urine volume;（2）OI:radial artery blood was taken for blood gas analysis after intubation（T₁）,120min（T₄）after the first pulmonary reexpansion,and 30min（T₆）after extubation,and arterial partial pressure of oxygen（Pa O₂）and arterial blood partial pressure of carbon dioxide（Pa CO₂）were recorded and OI was calculated;（3）Diaphragm Excursion（DE）and Diaphragm Thickness（DT）:Measure and record the patient’s DE and DT during calm breathing before intubation（T₀）and 30 minutes after extubation（T₆）;（4）Respiratory mechanics indicators:Record the peak airway pressure（Ppeak）,driving pressure（DP）,and lung compliance（CL）after intubation（T₁）,immediately after the first lung recruitment（T₂）,60 minutes after the first lung recruitment（T₃）,120 minutes after the first lung recruitment（T₄）,and after surgery（T₅at the end of suturing）;（5）Hemodynamic indicators:Record heart rate（HR）and mean arterial pressure（MAP）before intubation（T₀）,after intubation（T₁）,immediately after the first lung recruitment（T₂）,60 minutes after the first lung recruitment（T₃）,120 minutes after the first lung recruitment（T₄）,and after surgery（T₅）;（6）Postoperative conditions:the time of extubation,the incidence of hypoxemia after extubation,the number of days of hospital stay and postoperative pulmonary complications（Postoperative Pulmo）were tracked and recordedResults:1.There was no significant difference in preoperative and intraoperative general information such as age,gender,BMI,ASA grade,surgical time,pneumoperitoneum time,intraoperative fluid replacement volume,blood loss,and urine volume among the three groups of patients（P>0.05）.2.Compared with the same group at T0 time point（before intubation）and T5 time point（at the end of suture）,the MAP and HR of the three groups of patients at T1,T2,T3,and T4 time points decreased significantly（P<0.05）;The comparison between groups showed that there was no statistically significant difference in MAP and HR among the three groups of patients at different time points（P>0.05）,indicating that the establishment of laparoscopic pneumoperitoneum has a certain inhibitory effect on circulatory function.3.Intragroup comparison showed that compared with the T6 time point of the same group,the OI and Pa O2 of the three groups of patients at T1 and T4 time points increased.Inter group comparison showed that compared with Group B,the OI and Pa O2 of Group A and Group C at T6 time points decreased,with statistical significance（P<0.05）;There was no significant difference in Pa CO2 between the three groups of patients at different time points（P>0.05）.It is suggested that in laparoscopic gastrointestinal surgery,hypoxic lung recruitment has a greater advantage in improving OI and Pa O2 after extubation compared to hyperoxia lung recruitment.4.Compared with the same group at T0 time point,the DE and DT of the three groups of patients at T6 time point decreased significantly（P<0.05）;Compared between groups,there was no significant difference among the three groups of patients at each time point（P>0.05）.It is suggested that laparoscopic gastrointestinal surgery has a certain inhibitory effect on diaphragm motor function,while lung recruitment may not have a significant impact on diaphragm function during surgery.5.Intragroup comparison showed that compared with T1 and T5 time points,Ppeak and DP in all three groups increased at each time point,with statistical significance（P<0.05）;Inter group comparison showed that compared with Group C,Ppeak and DP of Group A and Group B decreased at time points T2,T3,T4,and T5,with a statistically significant difference（P<0.05）;A.There was no statistically significant difference in the comparison between Ppeak and DP groups at different time points between the two groups of patients（P>0.05）.It is suggested that PEEP incremental lung recruitment can reduce ventilation resistance in patients undergoing laparoscopic gastrointestinal surgery.6.Intragroup comparison showed that compared to T1 and T5 time points,the CL of each time point in the three groups decreased significantly（P<0.05）;Inter group comparison showed that compared with Group C,the CL levels of Group A and Group B increased at T2,T3,T4,and T5;Compared with Group A at the same time point,the CL of Group B increased significantly at T3,T4,and T5（P<0.05）.It is suggested that in laparoscopic gastrointestinal surgery,high and low oxygen concentration lung recruitment can improve lung compliance in patients during surgery,and low oxygen concentration lung recruitment may have more advantages.7.Compared with group B,the time of extubation was prolonged in group A and group C,and the incidence of hypoxemia was increased when air was inhaled after extubation,with a statistically significant difference（P<0.05）;There was no significant difference in postoperative hospitalization days and incidence of pulmonary complications among the three groups of patients（P>0.05）.Conclusion:In general anesthesia laparoscopic gastrointestinal surgery,PEEP implementing lung recruitment can effectively improve the oxygenation index after extubation in patients undergoing laparoscopic gastrointestinal surgery;Compared to 80%oxygen concentration lung recruitment,using 30%oxygen concentration lung recruitment has more advantages.This effect may be mainly related to improving lung compliance during mechanical ventilation in patients,and is not related to changes in diaphragm function,airway pressure,and driving pressure.