Haluszka J, Chartrand D A, Grassino A E, Milic-Emili J
Meakins-Christie Laboratories, McGill University, Montreal, Canada.
Am Rev Respir Dis. 1990 May;141(5 Pt 1):1194-7. doi: 10.1164/ajrccm/141.5_Pt_1.1194.
Dynamic pulmonary hyperinflation and intrinsic PEEP (PEEPi) are known to play an important role in causing acute respiratory failure in COPD patients. In the present study, we have explored (1) the prevalence and magnitude of PEEPi in stable COPD patients, and (2) the correlation of PEEPi with respiratory mechanics and PaCO2. In 96 stable COPD patients with varying degrees of airway obstruction, we measured pulmonary flow resistance (RL), dynamic lung compliance (CLdyn), breathing pattern, arterial blood gases, and dynamic PEEPi. Dynamic PEEPi was determined as a negative deflection in esophageal pressure from the start of inspiratory effort to the onset of inspiratory flow. A significant correlation was found between dynamic PEEPi and FEVi (% predicted; r = -0.56, p less than 0.001), between PEEPi and RL (r = 0.69, p less than 0.001), and between PaCO2 and PEEPi (r = 0.6, p less than 0.001). These results indicate that increased severity of airway obstruction promotes PEEPi and concomitant dynamic hyperinflation. This implies increased inspiratory work in the face of decreased effectiveness of the inspiratory muscles as pressure generators. The present results suggest that dynamic hyperinflation may play a role in causing chronic hypoventilation in COPD patients.
动态肺过度充气和内源性呼气末正压（PEEPi）在慢性阻塞性肺疾病（COPD）患者急性呼吸衰竭的发生中起着重要作用。在本研究中，我们探讨了（1）稳定期COPD患者中PEEPi的发生率和程度，以及（2）PEEPi与呼吸力学和动脉血二氧化碳分压（PaCO2）之间的相关性。在96例气道阻塞程度不同的稳定期COPD患者中，我们测量了肺血流阻力（RL）、动态肺顺应性（CLdyn）、呼吸模式、动脉血气和动态PEEPi。动态PEEPi被定义为从吸气开始到吸气气流开始时食管压力的负向偏转。发现动态PEEPi与第一秒用力呼气容积（FEV1，预计值百分比；r = -0.56，p < 0.001）、PEEPi与RL（r = 0.69，p < 0.001）以及PaCO2与PEEPi（r = 0.6，p < 0.001）之间存在显著相关性。这些结果表明气道阻塞严重程度增加会促进PEEPi和伴随的动态肺过度充气。这意味着在吸气肌作为压力发生器的有效性降低的情况下吸气功增加。目前的结果表明动态肺过度充气可能在COPD患者慢性通气不足的发生中起作用。
