无创正压通气不同辅助水平对慢性阻塞性肺疾病急性发作期患者呼吸做功的影响

目的 探讨无创正压通气(NIPPV)不同压力水平对慢性阻塞性肺疾病(COPD)急性发作期患者呼吸功的影响.方法 11例COPD急性发作期患者接受不同压力支持和呼气末正压水平的NIPPV,观察患者吸气肌肉用力和呼吸方式的变化.结果 (1)与自主呼吸(SB)相比,常规压力支持(PS)和高压力支持水平(H-PS)时的潮气量(VT)(P＜0.05)、分钟通气量(VE)(P＜0.01)均显著增高.高呼气末正压(H-PEEP)时的VT和VE无显著增高(P＞0.05).(2)SB时的吸气肌肉做功与呼气肌肉做功分别为0.89±0.24和0.03±0.04 J/L,3种通气方式时的患者吸气肌肉做功均明显减少(P＜0.01),PS、H-PEEP、H-PS分别为0.22 0.17、0.26±0.23和0.22±0.19J/L;但呼气肌肉做功也均显著增高(P＜0.01),PS、H-PEEP、H-PS分别为0.29 0.29、0.35±0.42和0.58±0.26 J/L.结论 本实验证实了在COPD急性发作期患者中,NIPPV可减轻患者的吸气肌肉负担,PS、H-PEEP和H-PS时患者吸气做功分别减少75%、71%和76%;但压力支持和呼气末正压水平过高可呼气肌肉做功.

Changes of work of breathing in patients with acute exacerbation of chronic obstructive pulmonary disease during non-invasive positive pressure ventilation

Objective To investigate the effect of non-invasive positive pressure ventilation(NIPPV)on the work of breathing(WOB)in patients with acute exacerbation of chronic obstructive pulmonary disease(COPD).Methods Eleven patients with acute exacerbation of COPD received pressure support ventilation(PSV)at different levels during NIPPV.The changes of inspiratory muscle effort and breathing pattern of the patients were observed.Results The average minute ventilation(VE,P<0.01)and tidal volume(VT,P<0.05)of the patients were significantly higher during routine PSV and high pressure support(H-PS)than those during spontaneous breathing(SB),and the breathing pattern of the patients did not undergo significant changes during high positive end expiratory pressure(H-PEEP).The WOB of the inspiratory muscles was reduced significantly during PSV as compared with that measured in SB(P<0.01),while the WOB of exspiratory muscle increased significantly(P<0.01).Conclusion NIPPV can relieve the load of the inspiratory muscles in patients with acute exacerbation of COPD,and the WOB of the inspiratory muscles can be reduced by PSV,H-PEEP and H-PS(by 75%,71% and 76%,respectively),but higher PSV during NIPPV can cause higher WOB of the exspiratory muscles.