Effects Of Different Ventilation Modes On Respiratory Mechanics Of Patients Undergoing Laparoscopic Colorectal Cancer Surgery

Objective To investigate the effects of different ventilation modes combined with PEEP on respiratory mechanics in laparoscopic colorectal cancer surgery,with a view to finding a more optimized ventilation mode in patients undergoing laparoscopic colorectal caner surgery.Methods 90 patients were selected for laparoscopic radical resection of colorectal cancer from December 2018 to December 2019,age 45 to 65,sex unlimited,BMI 18to 25 kg/m²,ASA II-III.Patients were divided into three groups?n=30?using the digital random table method:the volume-controlled ventilation mode group?V group?,the pressure-controlled ventilation mode group?P group?,and the pressure-controlled volume guaranteed ventilation mode group?G group?.The respiratory parameters of group V and group G were VT:7ml/kg,RR:10?16 beats/min,I:E=1:2,group P respiratory parameters were PIP=Set VT:7ml/kg,RR:10?16 beats/min,I:E=1:2,all three groups of PEEP were 5cm H₂O.Pre-anesthesia induction?T0?,supine anesthesia induction intubation after 10min?T1?,Trendelenburg postural pneumoperitoneum after 30min?T2?,Trendelenburg postural pneumoperitoneum after 60min?T3?,end of operation?T4?,extubation after 5min?T5?,recorded the average arterial pressure?MAP?of the patients,rate?HR?,pulse oxygen saturation?SPO2?;recorded T1?T4time point end-tidal pressure of carbon dioxide(P_ETCO2),peak airway pressure?Ppeak?,mean airway pressure?Pmean?,calculated lung compliance?Cdyn?.Arterial blood samples were collected at T1,T3,T4.PH,arterial carbon dioxide partial pressure?Pa CO₂?,arterial oxygen partial pressure?Pa O₂?,lactic acid?Lac?were recorded and calculated the oxygenation index?OI?.Results 1.There was no significant difference in general data and hemodynamics among the three groups.2.Compared with T1,the Pmean and Ppeak increased at T2and T3 in the three groups?P<0.05?,Cdyn decreased?P<0.05?,P_ETCO₂increased at T2 to T4 in the three groups?P<0.05?.Compared with G group,the Pmean and Ppeak increased at T1 to T4 in the V group?P<0.05?,Cdyn decreased?P<0.05?,P_ETCO2increased at T2 to T4 and P_ETCO2 increased in the P group?P<0.05?.3.Compared with T1,there was no significant difference in PH,Pa CO₂and Lac in the three groups?P>0.05?,Pa O₂and OI in the P group and G group were higher in the T3 and T4groups?P<0.05?,and there was no difference in the Pa O₂and OI in the V group at T3and T4?P>0.05?.Compared with group G,there was no statistical difference between group P and group V in PH,Pa CO₂,Pa O₂,Lac,OI at T1,T3,T4?P>0.05?.Conclusion PCV-VG and PCV ventilation mode have higher lung compliance and lower airway pressure than VCV ventilation mode.And because of the change of pulmonary compliance and resistance after pneumoperitoneum,PCV-VG needs less adjustment when setting ventilator parameters than PCV.Therefore,PCV-VG combined with PEEP ventilation mode is safer for patients undergoing laparoscopic colorectal cancer surgery.