Intermittent sigh breaths during high-frequency oscillatory ventilation in preterm infants: a randomised crossover study

OBJECTIVE: To determine if combining high-frequency oscillatory ventilation (HFOV) with additional sigh breaths would improve end-expiratory lung volume (EELV) and oxygenation in preterm infants.

DESIGN: Prospective interventional crossover study.

SETTING: Neonatal intensive care unit.

PATIENTS: Ventilated preterm infants <36 weeks corrected gestational age receiving HFOV.

INTERVENTIONS: Infants were randomly assigned to receive HFOV with sigh breaths followed by HFOV-only (or vice versa) for four alternating periods. Sigh breaths were delivered with an inspiratory time of 1 s, peak inspiratory pressure of 30 cmH20 and frequency of three breaths/min.

MAIN OUTCOME MEASURES: Electrical impedance tomography measured the effect of sigh breaths on EELV and ventilation distribution. Physiological variables were recorded to monitor oxygenation. Measurements were taken at 30 and 60 min postchange of HFOV mode and compared with baseline.

RESULTS: Sixteen infants (10 males, 6 females) with a median (range) gestational age at birth of 25.5 weeks (23-31), study weight of 950 g (660-1920) and a postnatal age of 25 days (3-49) were included in the study. The addition of sigh breaths resulted in a significantly higher global EELV (mean difference±95% CI) (0.06±0.05; p=0.04), with increased ventilation occurring in the posterior (dependent) and left lung segments, and improved oxygen saturations (3.31±2.10; p<0.01).

CONCLUSION: Intermittent sigh breaths during HFOV were associated in the short-term with an increased EELV in the posterior and left lungs, and improved oxygen saturations in preterm infants.