Study on the mechanical ventilation in management of multiple trauma patients with thoracic injury accompanied respiratory dysfunction
Cui Shitao,Sun Zhiyang,Liu Jianjun,et al.
Department of Emergency and Trauma Center,East Hospital Affiliated to Tong Ji University,Shanghai200120.
【Abstract】 Objective To evaluate the experience of clinical management on mechanical ventilation in man-agement of multiple trauma patients with thoracic injury accompanied respiratory dysfunction.Methods 26cases were treated with mechanical ventilation by using of SIMV and PSV.Results pH,PaO 2 ,PaCO 2 were significantly better af-ter ventilation than pre-ventilation(P<0.001).25cases were successfully removed ventilators.Only1case died.Conclusion The encouraging result of the mechanical ventilation in management of multiple trauma patients with tho-racic injury accompanied respiratory dysfunction deserves recommend,but the indications for mechanical ventilation have to be grasped.The key of improving the curative rate is decreasing complication such as pulmonary infection and shortening duration of mechanical ventilation.
Key words multiple trauma thoracic injury mechanical ventilation respiratory dysfunction
自主性辅助通气符合一定的呼吸生理,如由于重力作用,气体向肺上部,而血流向肺底部分布,底部肺泡易陷闭,自主呼吸的膈肌收缩,有利于肺底部通气增多,减少肺泡陷闭,改善气体分布和通气/血流比例失调,降低生理无效死腔。而控制性通气使自主呼吸的代偿作用消失;在相同的V T 下,有自主呼吸的压力支持通气(PSV)比控制通气(IP-PV)的吸气压低,有利于肺组织均匀扩张,降低肺切变力。自主通气良好的人机协调,避免人机对抗致峰压增高,从而减少机械通气肺损伤和减少对血流动力学的影响;控制通气易发生人机对抗和通气过度或通气不足;长期的控制通气会诱发呼吸肌萎缩。自主性辅助通气不仅减少呼吸肌做功,缓解呼吸肌疲劳,又能避免呼吸肌的废用性萎缩 [4] 。自主呼吸微弱或丧失者均可选用IPPV或SIMV,随着呼吸功能的好转,呼吸模式转为SIMV+PSV。如果患者在刚建立通气时就仅需要部分通气支持,一开始就应用SIMV+PSV模式。
3.4.1 呼吸机参数的设置 传统通气策略的潮气量(V T )为10~15ml/kg,但实验表明6ml/kg的V T 不为小V T 。为了预防呼吸机相关肺损伤,我们在临床上采用尽可能小的V T 以使SaO 2 维持在90%,PEEP3cmH 2 O就能扩张萎陷气道,提高气体弥散的功能,纠正通气/血流比例失调;FiO 2 %,PSV5~10cmH 2 O一般能够纠正缺氧。