Influence of lung collapse distribution on the physiologic response to recruitment maneuvers during noninvasive continuous positive airway pressure

Intensive Care Med. 2011 Jul;37(7):1095-102. doi: 10.1007/s00134-011-2239-8. Epub 2011 May 13.


Purpose: Noninvasive continuous positive airway pressure (n-CPAP) has been proposed for the treatment of hypoxemic acute respiratory failure (h-ARF). Recruitment maneuvers were shown to improve oxygenation, i.e., the ratio of arterial oxygen tension to inspiratory oxygen fraction (PaO2/FiO2), during either invasive mechanical ventilation, and n-CPAP, with a response depending on the distribution of lung collapse. We hypothesized that, during n-CPAP, early h-ARF patients with bilateral (B(L)) distribution of lung involvement would benefit from recruitment maneuvers more than those with unilateral (U(L)) involvement.

Methods: To perform a recruitment maneuver, once a minute we increased the pressure applied to the airway from 10 cmH2O to 25 cmH2O for 8 s (SIGH). We enrolled 24 patients with h-ARF (12 B(L) and 12 U(L)) who underwent four consecutive trials: (1) 30 min breathing through a Venturi mask (V(MASK)), (2) 1 h n-CPAP (n-CPAP1), (3) 1 h n-CPAP plus SIGH (n-CPAP(SIGH)), and (4) 1 h n-CPAP (n-CPAP2).

Results: Compared to V(MASK), n-CPAP at 10 cmH2O delivered via a helmet, increased PaO2/FiO2 and decreased dyspnea in both B(L) and U(L); furthermore, it reduced the respiratory rate and brought PaCO2 up to normal in B(L) only. Compared to n-CPAP, n-CPAP(SIGH) significantly improved PaO2/FiO2 in B(L) (225 ± 88 vs. 308 ± 105, respectively), whereas it produced no further improvement in PaO2/FiO2 in U(L) (232 ± 72 vs. 231 ± 77, respectively). SIGH did not affect hemodynamics in both groups.

Conclusions: Compared to n-CPAP, n-CPAP(SIGH) further improved arterial oxygenation in B(L) patients, whereas it produced no additional benefit in those with U(L).

Publication types

  • Comparative Study

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Continuous Positive Airway Pressure / instrumentation*
  • Female
  • Hemodynamics / physiology
  • Humans
  • Lung Volume Measurements
  • Male
  • Middle Aged
  • Pulmonary Atelectasis / physiopathology*
  • Respiratory Insufficiency / etiology
  • Respiratory Insufficiency / physiopathology
  • Respiratory Insufficiency / therapy*
  • Respiratory Mechanics / physiology