Objective: To describe the pattern and magnitude of lung volume change during open endotracheal tube (ETT) suction in infants receiving high-frequency oscillatory ventilation (HFOV).
Design: Prospective observational clinical study.
Setting: Tertiary neonatal intensive care unit.
Patients and participants: Seven intubated and muscle-relaxed newborn infants receiving HFOV.
Interventions: Open ETT suction was performed for 6 s at -100 mmHg using a 6-F catheter passed to the ETT tip after disconnection from HFOV. The HFOV was then recommenced at the same settings as prior to ETT suction.
Measurements and results: Change in lung volume (DeltaV (L)) referenced to baseline lung volume before suction was measured with a calibrated respiratory inductive plethysmography recording from 30 s before until 60 s after ETT suction. In all infants ETT suction resulted in significant loss of lung volume. The mean DeltaV (L) during suctioning was -13 ml/kg (SD 4 ml/kg) (p<0.0001 vs. baseline, repeated-measures ANOVA), with a mean 76.5% (SD 14.1%) of this volume loss being related to circuit disconnection. After recommencing HFOV lung volume was rapidly regained with mean DeltaV (L) at 60 s being 1 ml/kg (SD 4 ml/kg) below baseline (p>0.05, Tukey post-test).
Conclusions: Open ETT suction caused a significant but transient loss of lung volume in muscle-relaxed newborn infants receiving HFOV.