Pulmonary volume-feedback and ventilatory pattern after bilateral lung transplantation using neurally adjusted ventilatory assist ventilation

Abstract

Background: Bilateral lung transplantation results in pulmonary vagal denervation, which potentially alters respiratory drive, volume-feedback, and ventilatory pattern. We hypothesised that Neurally Adjusted Ventilatory Assist (NAVA) ventilation, which is driven by diaphragm electrical activity (EAdi), would reveal whether vagally mediated pulmonary-volume feedback is preserved in the early phases after bilateral lung transplantation.

Methods: We prospectively studied bilateral lung transplant recipients within 48 h of surgery. Subjects were ventilated with NAVA and randomised to receive 3 ventilatory modes (baseline NAVA, 50%, and 150% of baseline NAVA values) and 2 PEEP levels (6 and 12 cm H2O). We recorded airway pressure, flow, and EAdi.

Results: We studied 30 subjects (37% female; age: 37 (27-56) yr), of whom 19 (63%) had stable EAdi. The baseline NAVA level was 0.6 (0.2-1.0) cm H2O μV-1. Tripling NAVA level increased the ventilatory peak pressure over PEEP by 6.3 (1.8), 7.6 (2.4), and 8.7 (3.2) cm H2O, at 50%, 100%, and 150% of baseline NAVA level, respectively (P<0.001). EAdi peak decreased by 10.1 (9.0), 9.5 (9.4) and 8.8 μV (8.7) (P<0.001), accompanied by small increases in tidal volume, 8.3 (3.0), 8.7 (3.6), and 8.9 (3.3) ml kg-1 donor's predicted body weight at 50%, 100%, and 150% of baseline NAVA levels, respectively (P<0.001). Doubling PEEP did not affect tidal volume.

Conclusions: NAVA ventilation was feasible in the majority of patients during the early postoperative period after bilateral lung transplantation. Despite surgical vagotomy distal to the bronchial anastomoses, bilateral lung transplant recipients maintained an unmodified respiratory pattern in response to variations in ventilatory assistance and PEEP.

Clinical trial registration: NCT03367221.

Keywords: Hering–Breuer reflex; Neurally Adjusted Ventilatory Assist; lung transplantation; mechanical ventilation; pressure support ventilation.

Conflict of interest statement

Declarations of interest GG reports personal fees from Draeger Medical, Getinge, Fisher & Paykel, Biotest, personal Thermofisher and personal fees from Getinge, all unrelated with the present work; TM reports personal fees from Drager, Fisher & Paykel, and Mindray, outside the submitted work; AP received personal fees from Maquet, Novalung/Xenios, Baxter and Boehringer Ingelheim, outside the present work. All other authors declare that they have no conflicts of interests.

Copyright © 2021 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.