The Effect Of Different Methods Of Mechanical Ventilation On Respiratory Function In Sugery Patients With Prone Position Durning General Anesthesia

Objective The study is to observe the effect of three different methods ofmechanical ventilation on respiratory function in sugery patients with proneposition durning general anesthesia, and find a relatively ideal mechanicalventilation method for such patients, and then provide basis for safety andfeasibility durning clinical application.Methods Sixty patients (including28male and32female, ASA class Ⅰ orⅡ) undergoing operation of lumbosacral lesions durning general anesthesia wererandomly assigned into three even groups: conventional mechanical ventilationgroup (group A), tidal volume,10ml/kg, respiratory frequency,(8~12)breaths/min; low tidal volume mechanical ventilation group (group B), tidalvolume,6ml/kg, respiratory frequency,(12~20) breaths/min; low tidal volumecombined with low level PEEP mechanical ventilation group (group C), tidalvolume,6ml/kg and PEEP,5cmH2O, respiratory frequency,(12~20) breaths/min.All the three groups of patients were using total intravenous anesthesia and IPPVdurning the operation, but different mechanical ventilation methods, maintainingPETCO2in30~40mmHg. Blood gas indexes datum (PaO2, PaCO2,A-aDO2,RI=A-aDO2/PaO2) were acquisited and recoded in each group at the time beforeanesthesia (T1),10min after tracheal intubation with supine position (T2),10minafter tracheal intubation with prone position (T3),60min after tracheal intubationwith prone position (T4), and30min after tracheal extubation (T5). The respiratory mechanical parameters [Ppeak, Pmean, Cdyn=Vt/(Ppeak-PEEP)] wereobserved and record at the time10min after tracheal intubation with supineposition (T2),10min after tracheal intubation with prone position (T3),60minafter tracheal intubation with prone position (T4) in each group respectively.Results1.The difference of general information including sex, age, bodyweight, body mass index, ASA class, operation times didn’t reach ststisticalsignificance (P>0.05) among three groups.2.The patients’ blood gas indexes andparameters of respiratory mechanics durning the perioperative period were innormal range in each group. At the time point of T2, the Ppeakin group C wassignificantly lower than group A and group B (P<0.05), the Cdyn in group B wassignificantly lower than group A and group C (P<0.05). At the time points of T3and T4, the Ppeakwere significantly different in three groups (P<0.05), group A>group B>group C, the Pmeanand the Cdyn in group B were significantly lowerthan group A and group C; At the time point of T4, the PaCO2in group B wassignificantly higher than group A and group C; At the time point of T5,the A-aDO2in group C was significantly lower than group A and group B.Conclusion Different methods of mechanical ventilation had differentaffect on respiratory function in sugery patients with prone position durninggeneral anesthesia, the low tidal volum (6ml/kg) combined with low level PEEP(5cmH2O) mechanical ventilation can be used in clinic for patients durninggeneral anesthesia, for it can maintain respiratory function and improvedoxygenation function during general anesthesia.