Role of a successful spontaneous breathing trial in ventilator liberation in brain-injured patients

Abstract

Background: Spontaneous breathing trials (SBTs) have been shown to improve outcomes in critically ill patients. However, in patients with brain injury, indications for intubation and mechanical ventilation are different from those of non-neurological patients, and the role of an SBT in patients with brain injury is less established. The aim of the present study was to compare key respiratory variables acquired during a successful SBT between patients with successful ventilator liberation versus failed ventilator liberation.

Methods: In this prospective study, patients with brain injury (≥18 years of age), who completed a 30-min SBT, were enrolled. Airway pressure, flow, esophageal pressure, and diaphragm electrical activity (ΔEAdi) were recorded before (baseline) and during the SBT. Respiratory rate (RR), tidal volume, inspiratory muscle pressure (ΔPmus), ΔEAdi, and neuromechanical efficiency (ΔPmus/ΔEAdi) of the diaphragm were calculated breath by breath and compared between the liberation success and failure groups. Failed liberation was defined as the need for invasive ventilator assistance within 48 h after the SBT.

Results: In total, 46 patients (51.9±13.2 years, 67.4% male) completed the SBT. Seventeen (37%) patients failed ventilator liberation within 48 h. Another 11 patients required invasive ventilation within 7 days after completing the SBT. There were no differences in baseline characteristics between the success and failed groups. In-depth analysis showed similar changes in patterns and values of respiratory physiological parameters between the groups.

Conclusions: In patients with brain injury, ventilator liberation failure was common after successful SBT. In-depth physiological analysis during the SBT did not provide data to predict successful liberation in these patients.

Trial registration: The trial was registered at ClinicalTrials.gov (No. NCT02863237).

Keywords: Brain injury; mechanical ventilation; spontaneous breathing trial; ventilator liberation.

Conflict of interest statement

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-20-6407). AHJ reports personal fees from Liberate Medical (USA), outside the submitted work. LMH reports personal fees from Liberate Medical and Getinge, outside the submitted work. The other authors have no conflicts of interest to declare.

2021 Annals of Translational Medicine. All rights reserved.

Figures

Figure 1

Flowchart of patient enrollment in the study. MV, mechanical ventilation; SBT, spontaneous breathing trial.

Figure 2

Proportion of patients liberated from mechanical ventilation after a successful spontaneous breathing trial (SBT). Number of patients left at the time of observation is shown below the x-axis. Patients were followed up until they were reconnected to ventilation, extubated, tracheostomized, discharged from the hospital, or 28 days after the first successful SBT, whichever came first.

Figure 3

Respiratory muscle effort quantified as (A) inspiratory muscle pressure (ΔPmus,insp), (B) inspiratory esophageal pressure-time product (PTPes,insp), and (C) diaphragm electrical activity (ΔEAdi) during pressure support ventilation (baseline, gray area) prior to the spontaneous breathing trial (SBT) and during the course of the SBT for the successful (red dots) and failed (black boxes) liberation groups. In 9 patients, Pes-derived parameters could not be analyzed due to the low quality of the signals (1 in the failure group and 8 in the success group). Data are presented as median (interquartile range). **P

Figure 4

Changes in neuromechanical efficiency (NMEoccl) during pressure support ventilation (baseline, gray area) and during the course of the spontaneous breathing trial (SBT) in the successful (red dots) and failed (black boxes) liberation groups. Data are presented as median (interquartile range). No significant differences were observed at any time point within and between the 2 groups.