早期给予面罩比例辅助通气对慢性阻塞性肺疾病合并急性呼吸衰竭患者的生理影响。

Physiologic effects of early administered mask proportional assist ventilation in patients with chronic obstructive pulmonary disease and acute respiratory failure.

作者信息

Vitacca M, Clini E, Pagani M, Bianchi L, Rossi A, Ambrosino N

机构信息

Salvatore Maugeri Foundation IRCCS, Lung Function Unit, Medical Centre of Gussago, Italy.

出版信息

Crit Care Med. 2000 Jun;28(6):1791-7. doi: 10.1097/00003246-200006000-00016.

DOI:10.1097/00003246-200006000-00016

PMID:10890621

Abstract

OBJECTIVE

To evaluate the physiologic short-term effects of noninvasive proportional assist ventilation (PAV) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective, physiologic study.

SETTING

Respiratory intermediate intensive care unit.

PATIENTS

Seven patients with acute respiratory failure requiring noninvasive mechanical ventilation because of exacerbation of COPD.

INTERVENTIONS

PAV was administered by nasal mask as first ventilatory intervention. The setting of PAV involved a procedure to adjust volume assist and flow assist to levels corresponding to patient comfort. Volume assist was also set by means of the "run-away" procedure. Continuous positive airway pressure (CPAP) amounting to 2 cm H2O was always set by the ventilator. This setting of assistance (PAV) was applied for 45 mins. Thereafter, CPAP was increased to 5 cm H2O (PAV + CPAP-5) without any change in the PAV setting and was administered for 20 mins. Oxygen was delivered through a port of the mask in the attempt to maintain a target SaO2 >90%.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gases, breathing pattern, and inspiratory effort were measured during unsupported breathing and at the end of PAV, and breathing pattern and inspiratory effort were measured after 20 mins of PAV + CPAP-5. PAV determined a significant increase in tidal volume and minute ventilation (+64% and +25% on average, respectively) with unchanged breathing frequency and a significant improvement in arterial blood gases (PaO2 with the same oxygen supply, from 65 +/- 15 torr to 97 +/- 36 torr; PaCO2, from 80 +/- 11 torr to 76 +/- 13 torr; pH, from 7.30 +/- 0.02 to 7.32 +/- 0.03). The pressure-time product calculated over a period of 1 min (from 318 +/- 87 to 205 +/- 145 cm H2O x sec x min(-1)) was significantly reduced. PAV + CPAP-5 resulted in a further although not significant decrease in the pressure-time product calculated over a period of 1 min (to 183 +/- 110 cm H2O x sec x min(-1)), without additional changes in the breathing pattern.

CONCLUSIONS

Noninvasive PAV is able to improve arterial blood gases while unloading inspiratory muscles in patients with acute exacerbation of COPD.

摘要

目的

评估无创比例辅助通气（PAV）对慢性阻塞性肺疾病（COPD）急性加重患者的短期生理效应。

设计

前瞻性生理研究。

地点

呼吸中级重症监护病房。

患者

7例因COPD急性加重需要无创机械通气的急性呼吸衰竭患者。

干预措施

通过鼻罩给予PAV作为首次通气干预。PAV的设置包括将容量辅助和流量辅助调整至患者舒适对应的水平的程序。容量辅助也通过“失控”程序设置。呼吸机始终设置相当于2 cm H₂O的持续气道正压（CPAP）。这种辅助设置（PAV）应用45分钟。此后，CPAP增加至5 cm H₂O（PAV + CPAP - 5），PAV设置不变，持续20分钟。通过面罩端口输送氧气，试图维持目标SaO₂>90%。

测量指标及主要结果

在自主呼吸期间、PAV结束时测量动脉血气、呼吸模式和吸气努力，在PAV + CPAP - 5 20分钟后测量呼吸模式和吸气努力。PAV使潮气量和分钟通气量显著增加（平均分别增加64%和25%），呼吸频率不变，动脉血气显著改善（在相同氧气供应下，PaO₂从65±15 torr升至97±36 torr；PaCO₂从80±11 torr降至76±13 torr；pH从7.30±0.02升至7.32±0.03）。1分钟内计算的压力 - 时间乘积（从318±87降至205±145 cm H₂O×sec×min⁻¹）显著降低。PAV + CPAP - 5导致1分钟内计算的压力 - 时间乘积进一步降低（降至183±110 cm H₂O×sec×min⁻¹），尽管不显著，呼吸模式无额外变化。