Perry R J, Man G C, Jones R L
University of Alberta, Edmonton, Canada.
Chest. 1998 Apr;113(4):1028-33. doi: 10.1378/chest.113.4.1028.
To investigate the effects of positive end-expiratory pressure (PEEP) on end-expiratory lung volume (EELV) and mean oscillated flow rate (VOSC) during high-frequency chest compression (HFCC) in normal subjects and patients with severe COPD.
Comparative study.
Pulmonary function and lung mechanics laboratory, University of Alberta Hospitals.
Six normal subjects (five male; one female) and six patients with clinically stable COPD (five male; one female) with hypercapnia.
A pneumatic vest system was operated at 10 Hz with a mean chest wall pressure of 16 cm H2O to provide the HFCC. A closed-circuit spirometer system permitted measurement of HFCC- and PEEP-induced changes in EELV that were expressed as per cent baseline functional residual capacity (FRC). An isothermic chamber connected near the mouthpiece permitted measurement of VOSC.
For the normal subjects, HFCC caused a significant decrease in EELV to 82.0% of FRC (p < or = 0.01) and the addition of 4.8+/-0.5 cm H2O of PEEP during HFCC increased EELV to 97.5% FRC. In the COPD patients, HFCC decreased EELV to 92.3% of FRC (p < or = 0.01), and the addition of 3.7+/-1.0 cm H2O of PEEP increased EELV to 98.4% FRC. For the normal subjects, increasing EELV to near FRC caused VOSC during expiration to increase 14.6% (p < or = 0.01), but there was no significant effect on VOSC during inspiration (5.1% increase). In the COPD patients, PEEP increased VOSC during both inspiration (30.5%) and expiration (57.0%) (both, p < or = 0.01).
Addition of a modest amount of PEEP during HFCC prevents the decrease in EELV and increases VOSC during both phases of spontaneous breathing in COPD patients. This higher VOSC during HFCC+PEEP may improve the effectiveness of HFCC in clearing mucus from the lungs of patients with airway disease.
研究呼气末正压（PEEP）对正常受试者及重度慢性阻塞性肺疾病（COPD）患者在高频胸部按压（HFCC）期间呼气末肺容积（EELV）和平均振荡流速（VOSC）的影响。
对比研究。
阿尔伯塔大学医院肺功能与肺力学实验室。
6名正常受试者（5名男性，1名女性）和6名临床稳定的高碳酸血症COPD患者（5名男性，1名女性）。
使用气动背心系统以10Hz频率运行，平均胸壁压力为16cmH₂O，以提供HFCC。闭路肺量计系统可测量HFCC和PEEP引起的EELV变化，以基线功能残气量（FRC）的百分比表示。在靠近咬嘴处连接的等温箱可测量VOSC。
对于正常受试者，HFCC使EELV显著降低至FRC的82.0%（p≤0.01），在HFCC期间添加4.8±0.5cmH₂O的PEEP可使EELV增加至FRC的97.5%。在COPD患者中，HFCC使EELV降低至FRC的92.3%（p≤0.01），添加3.7±1.0cmH₂O的PEEP可使EELV增加至FRC的98.4%。对于正常受试者，将EELV增加至接近FRC会使呼气期间的VOSC增加14.6%（p≤0.01），但对吸气期间的VOSC无显著影响（增加5.1%）。在COPD患者中，PEEP使吸气（30.5%）和呼气（57.0%）期间的VOSC均增加（两者均p≤0.01）。
在HFCC期间添加适量的PEEP可防止COPD患者在自主呼吸的两个阶段中EELV降低，并增加VOSC。HFCC + PEEP期间这种较高的VOSC可能会提高HFCC清除气道疾病患者肺部黏液的有效性。
