Background: Refinement of ventilatory techniques remains a challenge given the persistence of chronic lung disease of preterm infants.
Methods: To test the hypothesis that proportional assist ventilation (PAV) will allow to lower the ventilator pressure at equivalent fractions of inspiratory oxygen (FiO(2)) and arterial hemoglobin oxygen saturation in ventilator-dependent extremely low birth weight infants in comparison with standard patient-triggered ventilation (PTV).
Design: Randomized crossover design.
Setting: Two level-3 university perinatal centers.
Patients: 22 infants (mean (SD): birth weight, 705 g (215); gestational age, 25.6 weeks (2.0); age at study, 22.9 days (15.6)).
Interventions: One 4-hour period of PAV was applied on each of 2 consecutive days and compared with epochs of standard PTV.
Results: Mean airway pressure was 5.64 (SD, 0.81) cm H(2)O during PAV and 6.59 (SD, 1.26) cm H(2)O during PTV (p < 0.0001), the mean peak inspiratory pressure was 10.3 (SD, 2.48) cm H(2)O and 15.1 (SD, 3.64) cm H(2)O (p < 0.001), respectively. The FiO(2) (0.34 (0.13) vs. 0.34 (0.14)) and pulse oximetry readings were not significantly different. The incidence of arterial oxygen desaturations was not different (3.48 (3.2) vs. 3.34 (3.0) episodes/h) but desaturations lasted longer during PAV (2.60 (2.8) vs. 1.85 (2.2) min of desaturation/h, p = 0.049). PaCO(2) measured transcutaneously in a subgroup of 12 infants was similar. One infant met prespecified PAV failure criteria. No adverse events occurred during the 164 cumulative hours of PAV application.
Conclusions: PAV safely maintains gas exchange at lower mean airway pressures compared with PTV without adverse effects in this population. Backup conventional ventilation breaths must be provided to prevent apnea-related desaturations.