Clinical application of adaptive support ventilation in weaning patients after general anesthesia

Objective To compare the different characteristics of adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation-pressure support ventilation (SIMV-PSV) mode in weaning patients after general anesthesia.Methods One hundred and twenty-eight patients received general anesthesia,ending in odd and even numbers by hospital number divided into ASV group (single number,62 cases) and SIMV-PSV group (double number,66 cases).The propofol dosage,duration of mechanical ventilation,duration of intubation,ventilator alarms,ventilator settings manipulations and each stage of the blood gas analysis,hemodynamic,respiratory mechanics were recorded.Results One hundred and twenty-eight patients completed the extubation.The propofol dosage,duration of mechanical ventilation,duration of intubation in ASV group were significantly shorter than those in SIMV-PSV group [(1.13 ± 0.33)mg/kg vs.(1.28 ±0.49) mg/kg,(169.8±36.5) min vs.(201.9 ±37.3) min,(197.2 ±38.9) min vs.(239.5 ± 42.3) min,P ＜ 0.05].There was no statistically significant difference in various stages of heart rate,mean arterial pressure,central venous pressure,pH,arterial carbon dioxide partial pressure,oxygenation index between two groups (P ＞0.05).In the first and second stages,tidal volume in ASV group was significantly higher than that in SIMV-PSV group [(543.6 ± 72.3) ml vs.(489.5 ± 68.7) ml,(513.9 ± 65.7)ml vs.(462.8 ± 61.7) ml,P＜ 0.05],respiratory rate in ASV group was significantly lower than that in SIMV-PSV group [(13.2 ± 3.6) times/min vs.(17.2 ±4.1) times/min,(15.1 ± 3.1) times/min vs.(16.8 ± 3.7)times/min,P ＜ 0.05].In the first stage,the mean airway pressure and peak airway pressure in ASV group were significantly lower than those in SIMV-PSV group [(8.2 ± 1.7) cm H2O (1 cm H2O =0.098 kPa) vs.(12.3 ± 3.1) cm H2O,(16.2 ± 2.9) cm H2O vs.(21.2 ± 4.3) cm H2O,P ＜ 0.05].The pulmonary dynamic compliance in ASV group was better than that in SIMV-PSV group [(64.8 ± 12.3) ml/cm H2O vs.(52.6 ±13.5) ml/cm H2O,P ＜ 0.05].The ventilator alarms,ventilator settings manipulations in ASV group were significantly shorter than those in SIMV-PSV group [(2.3 ± 1.6) times vs.(5.1 ± 1.9) times,(0.8 ± 0.5) times vs.(1.6 ± 0.8) times,P ＜ 0.05].Conclusion ASV weaning mode is safe and effective,which could accelerate the extubation and simplify the manipulation. Key words: Respiration,artificial;  Anesthesia,general;  Adaptive support ventilation; Weaning