术中小潮气量通气肺保护作用的研究

目的探讨术中小潮气量通气对老年患者的肺保护作用。方法 65岁以上择期下肢手术患者48例,根据潮气量不同随机分为小潮气量组（lower tidal volume ventilation,LTV组,6 ml/kg）和常规潮气量组（conventionaltidal volume ventilation,CTV组,10 ml/kg）,每组24例。观察手术过程中患者呼吸力学、通气功能变化,同时计算肺内分流率（Q_S/Q_T）。结果 TVT组患者术中气道压显著高于LVT组,胸肺顺应（Compl）无明显差异。TVT组PaCO_2于插管后显著降低,LVT组PaCO_2于插管后显著升高,组间比较P〈0.01。两组术中Q_S/Q●较术前显著增高,而LVT组较TVT组增高更明显（P〈0.05）。结论小潮气量通气能保持良好的通气效果,维持较低的气道压,减轻机械通气相关肺损伤,对肺有保护作用。小潮气量通气虽然增加肺内分流,但对老年患者术中短期应用仍是安全的。

Protective effects on lung function with lower tidal volume ventilation during orthopedic surgery for elderly patients

Objective To investigate the protective effects of lower tidal volume ventilation on lung function in elderly patients during orthopedic surgery.Methods Forty-eight patients aged over 65y with ASA classⅡorⅢ,undergoing orthopedic surgery with general anesthesia were randomly divided into 2 groups;lower tidal volume（6 ml/kg） ventilation group（LTV） and conventional tidal volume（10 ml/ kg） ventilation group（CTV） with 24 cases in each.The changes of respiratory functions were observed; alveolar-arterial oxygen difference（A-aDO₂） and pulmonary shunt fraction（Q_s/Q_T） were calculated. Results The peak and plateau airway pressure（Ppeak and Pplat） was significantly increased as the tidal volume increasing（P <0.05）.There was no significant difference in thorax-lung compliance between two groups.PaCO₂ of group CTV decreased significantly after intubation,while than of group LTV increased significantly,there was significant difference between two groups（P <0.01）.Q_S/Q_T increased in both groups during the operation,but it increased more significantly in group LTV than in group CTV （P<0.05）.There were no significant difference in PaO₂,PaCO₂ and Q_s/Q_T after operation between two groups.No hypoxemia case was found in both groups.Conclusion Lower tidal volume ventilation can maintain lower Ppeak and Pplat to reduce the lung injury.Lower tidal volume may transiently increase pulmonary shunt,but short-term application is safe in elderly patients during general anesthesia.