Article Text
Abstract
Objectives: To compare change in lung volume (ΔVL), using respiratory inductive plethysmography, time to recover pre-suction lung volume (trec) and the cardiorespiratory disturbances associated with open suction (OS) and closed suction (CS) in ventilated infants.
Design: Randomised blinded crossover trial.
Setting: Neonatal intensive care unit.
Patients: Thirty neonates, 20 receiving synchronised intermittent mandatory ventilation (SIMV) and 10 high-frequency oscillatory ventilation (HFOV, four receiving muscle relaxant).
Interventions: OS and CS were performed, in random order, on each infant using a 6FG catheter at −19 kPa for 6 seconds and repeated after 1 minute.
Outcome measures: ΔVL, oxygen saturation (Spo2) and heart rate were continuously recorded from 2 minutes before until 5 minutes after suction. Lowest values were identified during the 60 seconds after suction.
Results: Variations in all measures were seen during CS and OS. During SIMV no differences were found between OS and CS for maximum ΔVL or trec; mean (95% CI) difference of 3.5 ml/kg (−2.8 to 9.7) and 4 seconds (−5 to 13), respectively. During HFOV trec was longer during OS by 13 seconds (0 to 27) but there was no difference in the maximum ΔVL of 0.1 mV (−0.02 to 0.22). A small reduction in SpO2 with CS in the SIMV group mean difference 6% (2.1 to 9.8) was the only significant difference in physiological measurements.
Conclusions: Both OS and CS produced transient variable reductions in heart rate and Spo2. During SIMV there was no difference between OS and CS in ΔVL or trec. During HFOV there was no difference in ΔVL but a slightly longer trec after OS.