Effect Of Sustained Inflation Combined With Positive End-expiratory Pressure Ventilation On Oxygenation In Obese Patients Undergoing Laparoscopic Cholecystectomy Surgery

Objective:The study investigated the clinical value of sustained inflation（SI）combined with positive end-expiratory pressure（PEEP）in the management of anesthesia ventilation in mild to moderate obese patients undergoing laparoscopic cholecystectomy.Methods:Seventy-two obese patients undergoing laparoscopic cholecystectomy were divided into three groups radomly,control group（C,n=24）and SI+PEEP（low,n=24）,and SI+PEEP（medium,n=24）.All of them were to receive pressure control ventilation（PCV）at the beginning of opetation.After the establishment of pneumoperitoneum,the inspiration pressure（Pinsp）value was adjusted to the original minute ventilation（MV）value,and mechanical ventilation was performed with the new value.After pneumoperitoneum was relieved,Pinsp was adjusted to the original MV volume again.And at this time point,they were randomized to receive machanical ventilation with PEEP of 5cmH₂O（C,n=24）,SI once combined with PEEP of 5cmH₂O（SI+PEEP（low,n=24））or SI once combined with 8cmH₂O（SI+PEEP（medium,n=24））until the end of the operation.The index of blood gas analysis,circulatory dynamics and respiratory machanics were observed afrer the patient were entering the operating roomT₀,10mins after induction of anesthesia T₁,after half an hour of the pneumoperitoneum T₂,before extubation T₃,recorded the lowest SpO₂ within 10minutes after tube extraction with oxygen free state and SpO₂ at 30 minutes after tube extraction.Results:Heart rate（HR）was decreased at T₁ in three groups;mean arterial blood pressure（MAP）was decreased at T₂ in group C and SI+PEEP（low）,decreased at T₂、T₃ in group SI+PEEP（medium）;P_aO₂ was increased at T₁、T₂ and T₃ in three groups;OI was lowest at T₃ in group C;P_aCO₂ was decreased at T₁ but increased at T₂、T₃ in group C,and decreased at T₁ but increased at T₂ in group SI+PEEP（low）and in group SI+PEEP（medium）,it was decreased at T₁、T₃;the above indicators had significant differences compared with T₀（P<0.05）.PetCO₂ was increased at T₂、T₃ in group C,increased at T₂ in group SI+PEEP（low）and SI+PEEP（medium）but decreased at T₃ in group SI+PEEP（medium）;Cdyn was decreased at T₂ and T₃ in three groups;the above indicators had significant differences compared with T₁（P<0.05）.Compared with group C,the levels of P_a O₂,OI and Cydn were increased at T₃ in SI+PEEP（medium）group,while the levels of P_aCO₂ and PetCO₂ were decreased;P_aO₂,OI and Cydn was increased at T₃in group SI+PEEP（low）（P<0.05）.Compared with group C,SpO₂ was higher at the lowest SpO₂ within 10 minutes after tube extraction with oxygen free state point in both SI+PEEP（low）and SI+PEEP（medium）groups（P<0.05）.There were no severe circulatory dynamics fluctuations,severe oxygenation disorders and mechanical ventilation-related complications in three groups during the operation.Conclusion:Sustained inflation combined with PEEP of moderate level can improve oxygenation and lung compliance in obese patients undergoing laparoscopic cholecystectomy, contribute to the excretion of superfluous carbon dioxide（CO₂）in the body after operation,further reduce the risk of hypoxia after operation,and has no significant adverse effect on its circulatory dynamics.