The effect of pressure support on imposed work of breathing during paediatric extubation readiness testing

• Published in: Annals of intensive care Vol. 9; no. 1; pp. 78 - 7
• Main Authors: van Dijk, Jefta, Blokpoel, Robert G. T., Koopman, Alette A., Dijkstra, Sandra, Burgerhof, Johannes G. M., Kneyber, Martin C. J.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 02.07.2019; Springer Nature B.V; SpringerOpen
• Subjects: Airway management; Anesthesiology; Child; Continuous positive airway pressure; Critical Care Medicine; Emergency Medicine; Extubation readiness test; Imposed work of breathing; Intensive; Intensive care; Mechanical ventilation; Medicine; Medicine & Public Health; Paediatric intensive care; Patient assessment; Pediatrics; Pressure support; Respiratory therapy; Ventilators; Pressure support; Imposed work of breathing; Child; Mechanical ventilation; Paediatric intensive care; Extubation readiness test
• ISSN: 2110-5820; 2110-5820
• DOI: 10.1186/s13613-019-0549-0

Background Paediatric critical care practitioners often make use of pressure support (PS) to overcome the perceived imposed work of breathing (WOBimp) during an extubation readiness test (ERT). However, no paediatric data are available that shows the necessity of adding of pressure support during such tests. We sought to measure the WOBimp during an ERT with and without added pressure support and to study its clinical correlate. This was a prospective study in spontaneously breathing ventilated children < 18 years undergoing ERT. Using tracheal manometry, WOBimp was calculated by integrating the difference between positive end-expiratory pressure (PEEP) and tracheal pressure (Ptrach) over the measured expiratory tidal volume (VTe) under two paired conditions: continuous positive airway pressure (CPAP) with and without PS. Patients with post-extubation upper airway obstruction were excluded. Results A total of 112 patients were studied. Median PS during the ERT was 10 cmH 2 O. WOBimp was significantly higher without PS (median 0.27, IQR 0.20–0.50 J/L) than with added PS (median 0.00, IQR 0.00–0.11 J/L). Although there were statistically significant changes in spontaneous breath rate [32 (23–42) vs. 37 (27–46) breaths/min, p  < 0.001] and higher ET-CO 2 [5.90 (5.38–6.65) vs. 6.23 (5.55–6.94) kPa, p  < 0.001] and expiratory Vt decreased [7.72 (6.66–8.97) vs. 7.08 (5.82–8.08) mL/kg, p  < 0.001] in the absence of PS, these changes appeared clinically irrelevant since the Comfort B score remained unaffected [12 (10–13) vs. 12 (10–13), P  = 0.987]. Multivariable analysis showed that changes in WOBimp occurred independent of endotracheal tube size. Conclusions Withholding PS during ERT does not lead to clinically relevant increases in WOBimp, irrespective of endotracheal tube size.