| Objective To investigate the effects of inverse ventilation on respiratory mechanics,intraoperative oxygenation and CO2excretion,hemodynamics and lung injury in obese patients undergoing laparoscopic sleeve gastrectomy.Methods From December 2021 to September 2022,62 obese patients who underwent laparoscopic sleeve gastrectomy in Inner Mongolia Autonomous Region People’s Hospital were selected,aged 18～50 years,ASA grade II～III,body mass index（BMI）>30kg/m2,divided into experimental group（n=31）and control group（n=31）by random number table method,and finally completed 60 obese patients in this study,including 30 cases in the experimental group and 30 cases in the control group.The pressure-controlled volume-guaranteed ventilation mode（PCV-VG）was used in both groups,and the tidal volume was set at 7 ml/kg,the positive end-expiratory pressure（PEEP）was 7 cm H2O,the inspired oxygen concentration（Fi O2）was60%,the inspiration/expiration ratio（I:E）was set at 1:2,and the initial respiratory rate was set at 12 breaths/min,and the respiratory rate was adjusted to maintain the PETCO2 between35～45mm Hg.After pneumoperitoneum was established,I:E was set to 2:1 in the experimental group and I:E was kept constant in the control group until the end of mechanical ventilation.General data of both groups were recorded,including gender,age,ASA classification,body mass index,operation time,pneumoperitoneum time,fluid volume and urine volume;respiratory mechanics parameters were recorded at 5mim after tracheal intubation（T1）,5min after pneumoperitoneum（T2）,30min after pneumoperitoneum（T3）,60min after pneumoperitoneum（T4）,90min after pneumoperitoneum（T5）,including expiratory tidal volume（VT）,dynamic lung peak airway pressure（Ppeak）,mean airway pressure（Pmean）,compliance（Cdyn）,end-expiratory partial pressure of carbon dioxide(PETCO2)and respiratory rate（RR）,and calculation of driving pressure;heart rate（HR）and mean arterial pressure（MAP）were recorded at time points T1、T2、T3、T4、T5;arterial blood was obtained before induction of anesthesia（T0）and 90 min after pneumoperitoneum（T5）.Arterial blood was measured before induction of anesthesia（T0）and 90 min after pneumoperitoneum（T5）:arterial partial pressure of oxygen（Pa O2）,arterial partial pressure of carbon dioxide（Pa CO2）,acid-base（p H）,and oxygenation index（OI）.The concentrations of Clara cell protein 16（CC16）and alveolar surface-associated protein A（SP-A）were measured by enzyme-linked immunosorbent assay in intrajugular venous blood drawn before induction of anesthesia（T0）and 30 min after extubation（T6）in both groups.Results1.Comparison of the general information:there were no notably significant difference in baseline comparison between the two groups in terms of gender,age,ASA classification,BMI,operation time,pneumoperitoneum time,infusion volume and urine volume（P>0.05）;2.Comparison of respiratory mechanics:Ppeak,Pmean,and driving pressure at T2,T3,T4,and T5were higher than those at T1,while Cdyn was lower than that at T1 in both groups;Pmean at T4was notably higher than that at T2 in the experimental group,and the differences were all statistically significant（P<0.05）.At T2,T3,T4,and T5,Ppeak,driving pressure,and were notably lower in the experimental group than those in the control group,while Pmean and Cdyn were notably higher in the experimental group than those in the control group,and the differences were all statistically significant（P<0.05）.3.Comparison of CO2 emission:PETCO2 and RR at T2,T3,T4and T5 were higher than those at T1,while Cdyn was lower than that at T1 in both groups;PETCO2 at T3,T4 and T5 were higher than those at T2 in both groups;RR at T4 and T5were notably higher than those at T2in the experimental group;RR at T4was higher than that at T2 and T3 in the control group,and the differences were all statistically significant（P<0.05）.At T2,T3,T4and T5,the RR of the experimental group was significantly lower than that of the control group,and the differences were all statistically significant（P<0.05）.4.Comparison of hemodynamics:in the experimental group,HR at T4 and T5 was higher than that at T1,T2 and T3;MAP at T5 was higher than that at T1,and the difference was statistically significant（P﹤0.05）;in the control group,HR at T5 was higher than that at T2;HR at T4 and T5 was higher than that at T3,and the difference was statistically significant（P﹤0.05）.5.Comparison of blood gas analysis:Pa O2 and Pa CO2at T5 were significantly higher than those at T0,while p H was notably lower than that at T0 in both groups;OI at T5 was notably higher than that at T0 in the experimental group,and the differences were notably significant（P<0.05）.Pa O2 and OI in the experimental group were higher than those in the control group at T5,while Pa CO2 was notably lower than that in the control group,and the differences were notably significant（P<0.05）.6.Comparison of lung injury indexes:CC16 and SP-A expression levels were significantly higher in both groups at T6than at T0;at T6,CC16 and SP-A expression levels were lower in the experimental group than in the control group,and the differences were statistically significant（P<0.05）.ConclusionInverse ratio ventilation applied to obese patients undergoing laparoscopic sleeve gastrectomy reduced intraoperative Ppeak and driving pressure,increased Pmean and Cdyn,reduced the setting of RR,improved intraoperative ventilation;reduced Pa CO2,increased Pa O2and OI,improved intraoperative oxygenation;reduced the expression of CC16 and SP-A,reduced the degree of lung injury,and did not adversely affect hemodynamics in obese patients.Therefore,inverse ventilation in PCV-VG ventilation mode is a safe and feasible ventilation strategy for obese patients undergoing laparoscopic sleeve gastrectomy. |
PDF Full Text Request