Respiratory effort during noninvasive positive pressure ventilation and continuous positive airway pressure in severe acute viral bronchiolitis

ObjectivesTo assess if noninvasive positive pressure ventilation (NIPPV) is associated with a greater reduction in respiratory effort as compared to continuous positive airway pressure (CPAP) during severe acute bronchiolitis, with both supports set either clinically or physiologically. MethodsTwenty infants (median [IQR] age 1.2 [0.9; 3.2] months) treated <24 h with noninvasive respiratory support (CPAP Clin, set at 7 cmH(2)O, or NIPPV Clin) for bronchiolitis were included in a prospective single-center crossover study. Esogastric pressures were measured first with the baseline support, then with the other support. For each support, recordings were performed with the clinical setting and a physiological setting (CPAP Phys and NIPPV Phys), aiming at normalising respiratory effort. Patients were then treated with the optimal support. The primary outcome was the greatest reduction in esophageal pressure-time product (PTPES/min). Other outcomes included improvement of the other components of the respiratory effort. ResultsNIPPV Clin and Phys were associated with a lower PTPES/min (164 [105; 202] and 106 [78; 161] cmH(2)O s/min, respectively) than CPAP Clin (178 [145; 236] cmH(2)O s/min; p = 0.01 and 2 x 10(-4), respectively). NIPPV Clin and Phys were also associated with a significant reduction of all other markers of respiratory effort as compared to CPAP Clin. PTPES/min with NIPPV (Clin or Phys) was not different from PTPES/min with CPAP Phys. There was no significant difference between physiological and clinical settings. ConclusionNIPPV is associated with a significant reduction in respiratory effort as compared to CPAP set at +7 cmH(2)O in infants with severe acute bronchiolitis. CPAP Phys performs as well as NIPPV Clin.