Ventilatory choices for intubated patients during helicopter stretcher winching

Abstract

The winching of intubated patients on a stretcher into a helicopter is a rare event. Intermittent positive pressure ventilation is mandatory, which can either be performed manually with a self-inflating bag, or automatically using a portable ventilator. Theoretically automatic ventilation would provide improved oxygenation, more stable arterial carbon dioxide levels and a reduced risk of airway disconnection. Furthermore, the stretcher attendant may better perform winching procedures with higher situational awareness, contributing to crew and patient safety. However ventilator failure, and the diagnosis and management of such, is of concern. The aim of this study is to compare automatic against manual ventilation during intubated helicopter stretcher winching. The trial had two phases. Initially a static winch on a hoist simulator was performed, followed by live winching into a helicopter. All stretcher attendants performed two winches with an intubated manikin. During one winch, the manikin was manually ventilated, and an automatic ventilator was used for the other. Airway pressures were measured. Automatic ventilation did not fail. Compared with automatic ventilation, manual ventilation displayed significant pauses, inconsistent rates and both high and low airway pressures. Automatic ventilation permitted better situational awareness and performance in winching manoeuvres. One airway disconnection occurred during manual ventilation. During helicopter winching, automatic ventilation is superior in providing controlled, consistent and reliable ventilation for intubated patients. The stretcher attendant is also able to provide more attention to the winching manoeuvres with subsequent safety gains. The risk of automatic ventilator failure is low.