Application Of Minimal Tidal Volume Mechanical Ventilation Strategy In Patients Undergoing Flexible Ureteroscopic Lithotripsy

Objective:To evaluate the effect of minimal tidal volume mechanical ventilation on patients undergoing flexible ureteroscopic lithotripsy.Methods:74 American Society of Anesthesiologists physical status?or?patients,aged 25-60years,with a BMI of 18-28kg/m²,scheduled for ureteroscopic holmium laser lithotripsy under tracheal intubation anesthesia,were divided into 3 groups according to different ventilation methods randomly:Conventional mechanical ventilation group?group C,n=20?,Apena group?group A,n=28?and Minimal tidal volume mechanical ventilation group?group M,n=26?.The ventilation mode of group C was used V_T 6 ml/kg and RR12.In group A,V_T 6 ml/kg and RR 12 were used,mechanical ventilation was suspended at the beginning of lithotripsy and resumed after the lithotripsy was finished,the longest maximum pause time was 5 minutes and the times of pause were determined according to the condition of lithotripsy.In group M,V_T 6 ml/kg and RR 12 were used,the minimal tidal volume mechanical ventilation mode was used when the lithotripsy started,then we used V_T 3ml/kg and RR 24,as well as chose the SpO₂ decreased to 95%as the limit of restoring normal mechanical ventilation.1ml blood samples from the radial artery and the internal jugular vein were collected before anesthesia?T₁?,before surgery?T₂?,before the first of controlled breath?T₃?,after the last controlled breath immediately?T₄?,30 minutes after extubation?T₅?for blood gas analysis immediately,then recording pH,PaCO₂,calculated the arterial and internal jugular venous oxygen pressure difference?Pa-jvO₂?,blood oxygen saturation difference?Sa-jvO₂?,oxygenation index?OI?and cerebral extraction rate of oxygen?CERO₂?.Blood samples were collected from the vein for determination of Clara cell secretory protein,S100?protein,Myoglobin,Troponin I and T,Creatine Kinase-MB At T₁,T₅,and 24 hours after surgery?T₆?.The cerebral regional oxygen saturation?rSO₂?,the total time of laser lithotripsy and the score of the mobility of stones from surgeon were recorded.Results:Compared with group C,the value of PaCO₂ in group A was significantly higher,while the value of pH and OI was significantly lower at T₄?P<0.0167?.Compared with group A,the value of PaCO₂ in group M was significantly lower,while the value of pH and OI was significantly higher at T₄?P<0.0167?.There was no significant difference in CC16,rSO₂,CERO₂,Pa-jvO₂,Sa-jvO₂,S100?protein,Myoglobin,Creatine Kinase-MB,Troponin I and T among three groups at each time point.The time of laser lithotripsy was significantly shortened,and the surgeon was more satisfied with the condition of the lithotripsy?P<0.001?in group A and group M.Conclusion:The minimal tidal volume mechanical ventilation strategy can be safely and effectively applied to flexible ureteroscopic lithotripsy,it can be used as a safe and feasible alternative ventilation method for the surgery.