Effect of pediatric ventilation weaning technique on work of breathing

Abstract

Background: Ventilator liberation is one of the most challenging aspects in patients with respiratory failure. Most patients are weaned through a transition from full to partial respiratory support, whereas some advocate using a continuous spontaneous ventilation (CSV). However, there is little scientific evidence supporting the practice of pediatric ventilator liberation, including the timing of onset of and the approach to weaning mode. We sought to explore differences in patient effort between a pressure controlled continuous mode of ventilation (PC-CMV) [in this cohort PC assist/control (PC-A/C)] with a reduced ventilator rate and CSV, and to study changes in patient effort with decreasing PS.

Methods: In this prospective physiology cross-over study, we randomized children < 5 years to first PC-A/C with a 25% reduction in ventilator rate, or CSV (continuous positive airway pressure [CPAP] + PS). Patients were then crossed over to the other arm. Patient effort was measured by calculating inspiratory work of breathing (WOB) using the Campbell diagram (WOBCampbell), and by pressure-rate-product (PRP) and pressure-time-product (PTP). Respiratory inductance plethysmography (RIP) was used to calculate the phase angle. Measurements were obtained at baseline, during PC-A/C and CPAP + PS, and during decreasing set PS (maximum -6 cmH2O).

Results: Thirty-six subjects with a median age of 4.4 (IQR 1.5-11.9) months and median ventilation time of 4.9 (IQR 3.4-7.0) days were included. Nearly all patients (94.4%) were admitted with primary respiratory failure. WOBCampbell during baseline [0.67 (IQR 0.38-1.07) Joules/L] did not differ between CSV [0.49 (IQR 0.17-0.83) Joules/L] or PC-A/C [0.47 (IQR 0.17-1.15) Joules/L]. Neither PRP, PTP, ∆Pes nor phase angle was different between the two ventilator modes. Reducing pressure support resulted in a statistically significant increase in patient effort, albeit that these differences were clinically negligible.

Conclusions: Patient effort during pediatric ventilation liberation was not increased when patients were in a CSV mode of ventilation compared to a ventilator mode with a ventilator back-up rate. Reducing the level of PS did not lead to clinically relevant increases in patient effort. These data may aid in a better approach to pediatric ventilation liberation. Trial registration clinicaltrials.gov NCT05254691. Registered 24 February 2022.

Keywords: Mechanical ventilation; Pediatrics; Phase angle; Pressure–rate-products; Pressure–time-product; Weaning; Work of breathing.

Conflict of interest statement

MK received lecture fees from Vyaire, Mettawa, Ill, USA and has received technical support from Vyaire, Mettawa, Ill, USA and Applied Biosignals, Weener, Germany. The remaining authors declare that they have no competing interests.

© 2022. The Author(s).

Figures

Fig. 1

Study design of the different data collection moments during the two different weaning strategies (top figure) and the three step downgrading of pressure support (bottom figure). CRF = case record file, Pes = esophageal pressure, RIP = respiratory inductance plethysmography

Fig. 2

The work of breathing calculated through the gold standard, the Campbell diagram (Joules/L). a shows the work of breathing during the different weaning strategies. b shows the work of breathing during downtapering of pressure support. *p < 0.05

Fig. 3

The work of breathing calculated through measuring the difference in esophageal pressure (∆Pes) in cmH2O. a shows the ∆Pes during the different weaning strategies. b shows the ∆Pes during downtapering of pressure support. *p < 0.05