术前、术中肺通气功能与术后呼吸衰竭的关系

Correlation between Pre- and Intra-Operative Ventilatory Function and Postoperative Respiratory Failure

目的探讨机械通气时呼吸力学与术前肺功能的关系．确定术前通气功能参数能否预测术后呼吸衰竭。方法择期行肺切除术的原发性肺癌病人100例．ASAⅠ级或Ⅱ级，术前测定肺功能：一秒用力呼气容量（FEV1）、用力肺活量（FVC）、一秒用力呼气量与用力肺活量之比（FEV1／FVC％）、最大肺活量（VC）、最大通气量（MVV）、75％肺活量位用力呼气流速（FEh）、最大中期呼气流速（MMEFm）、功能残气量（FRC）、残气量与肺总量之比（RV/TLC％）；测定脉冲震荡肺功能：共振频率（Fres）、呼吸总阻抗（Zres）、中心阻力（Rc）、5Hz和20Hz时粘性阻力（R5、R30）。分别记录插管后机械通气初始和开胸单肺通气后双肺气道峰压（Tpeak）、双肺胸肺顺应性（TCT）和单肺气道峰压（Opeak）、单肺胸肺顺应性（OCT），取其平均值。Opeak和OCT与身高、体重及肺功能的关系采用多元逐步回归。一般情况和肺功能与术后呼吸衰竭的关系采用非条件Logistic回归分析。根据术后是否发生呼吸衰竭分为2组：呼吸衰竭组（RF）和非呼吸衰竭组（NRF）。结果Opeak与Zres、身高、体重和FEF。呈线性关系（R2=0．504），OCT与Zres、身高、VC和RVfrLC％呈线性关系（R^2=0.602）。与NRF组比较，RF组FEV1、FVC、FEV1／FVC％、MVV、MMEFw均降低（P〈0．01）。年龄≥60岁的老年患者FEV1≤60％、FEV1／FVC≤60％、MVV≤50％、MMEn％≤35％时，RF组术后呼吸衰竭发生率高于NRF组（P〈0．05）。Logistic回归表明．年龄和MVV是术后呼吸衰竭的两个主要影响因素。结论术中单肺通气时的气道峰压和胸肺顺应性分别与身高、体重和术前肺功能呈线性相关。中度肺功能减退的老年患者行胸科手术后发生呼吸衰竭的风险性大：年龄和MVV是术后呼吸衰竭的两个主要影响因素。

Objective To investigate the correlation between the mechanics of breathing during mechanical ventilation and the preoperative ventilatory function,and to determine the preoperative ventilatory function parameters predicted postoperative respira-tory faiture （pRF）. Methods One hundred ASA Ⅰ or Ⅱ patients with primary hmg cancer undergoing elective lung resection were studied. Forced expiration volume in 1^th second （FEVI）, forced vital capacity （FVC）, forced expiration volume in 1^th second/forced vital capacity （FEV1/FVC% ）,maximal vital volume （VC）,maximal ventilatory volume （MVV）, forced expiration flow at 75% vital capacity （FEF75）, maximal mid-expiratory flow （MMEF 75/25）, functional residual capacity （FRC）, residual volume / total lung capacity （RV / TLC %）, resonance frequency （Fres）, total respiratory resistance （Zprs）, central resistance （Rc）, viscous resistance at 5 Hz and 20 Hz （R5 , R30 ） were measured before operation. Anesthesia was induced with iv midazolam, sufentanil, propofol and recuronium. Double-lumen catheter was inserted and correct placement was confirmed by fiberoptic bronchoscopy. The patients were mechanically ventilated （Vt 8-10 ml/kg, RR 12-15 bpm, 1：E=1：1.5）, anesthesia was maintained with sufentanil, propofol, sevotlttraae and veeuronium. The patients were completely paxalysed during operation （TOF=0）. Peak airway pressure （Ppath） and lung-chest wall compliance （CT） were measured when both lungs and one-lung were ventilated before and after chest was opened. Postoperative respiratory failure was defined as： （1）SOB on 2^nt-7^th postoperative day; （2） PaO2/ FiO2 〈270; （3） PaCO,. 〉50 mmHg and （4） postoperative mechanical ventilation 〉48 h. Results （1）A significant correlation existed between Ppeak and CT during onelung ventilation and body height and weight and preoperative ventilatory function. （2）FEV1, FVC, FEV1 / FVC, MVV and MMEF75/25 were significantly lower in patients developed pRF. The morbidity of pRF was significantly higher in patients aged 〉60yr. Conclusion Age and MVV are the two most important factors for predicting pRF in postoperative patients with lung eaneer. Key words Respiratory funetion test Respiratory insuffieieney/surgery Respiratory mechanics Lung Neoplasms