Alveolar recruitment with non-invasive mechanical ventilation (C-PAP) in patients with nonobstructive respiratory failure

Introduction

Non-invasive mechanical ventilation (NIMV) is able to reduce reintubation especially in patients with exacerbation of COPD. Results have not been reached in critically ill patients with nonobstructive respiratory failure (NORF). However, the NIMV in most of these studies has been applied without making an effort to open the lung and adjusting the C-PAP after opening up the lung using a clinical approach. Our aim was to evaluate the effects of applying recruitment manoeuvres (RM) with C-PAP and titrate it according to clinical decremental C-PAP trial in patients with NORF.

Methods

NORF patients for whom NIMV was indicated between January 2008 and July 2009 were included and submitted to the NIMV-RM protocol when a trained team was available. Bi-PAP and a full face mask were used. The inclusion criteria were at least two of the following: respiratory rate (RR) >30, accessory muscle activity, saturation ≤90% with FiO₂ ≥50% and consolidation areas on thorax X-ray. Gradual increasing of C-PAP (2 cmH₂O) was used from 10 to 20 cmH₂O. Each level of C-PAP was sustained for 5 minutes according to tolerance. The C-PAP after RM was adjusted when the maximal tidal volume (VT) was reached, pulse oximetry (PO) did not show any substantial change and when the patient was comfortable. Demographic data, APACHE II score and lung injury score (LIS) were measured. Cardiac rate (CR), RR, arterial pressure (AP), PO, minute ventilation (VE) and percentage of mask leak (PML) were recorded through the RM. Arterial blood gases were measured pre-RM, 1, 12 and 24 hours after RM. Variables are expressed as median (range). ANOVA by repeated measures or Kruskal-Wallis was used, P < 0.05 was considered significant.

Results

Fourteen patients were included. Age, APACHE II and LIS were: 56 (17 to 80); 14 (4 to 21) and 2 (1.3 to 2.7). The PaO₂/FiO₂ ratio increased from 169.1 ± 69.7 (basal) to 261 ± 106 after 1 hour of RM (P = 0.02). Improvement was preserved at 12 and 24 hours, 280 ± 69 and 295 ± 73, respectively. The C-PAP level 1 hour after RM was 14.9 ± 2.4, and 14.1 ± 1.9 at 24 hours post RM. The hemodynamic stability, RR, AP, PML and VE did not change during and after the RM.

Conclusions

RM with gradual increments of C-PAP is safe. RM in patients with NORF could be an alternative to rescue patients with poor outcome with NIMV alone.