Einfluss eines Beatmungshelmes auf die Leistung zweier verschiedener Intensivbeatmungsgeräte im Vergleich zu einer Gesichtsmaske und zur invasiven Beatmung - Eine experimentelle Lungenmodelluntersuchung

Abstract

Noninvasive ventilation (NIV) is increasingly used in intensive care medicine, but only little information is available how different NIV interfaces affect the performance of a ventilatory system. Delay times, pressure time products (PTP), and wasted efforts were compared during inspiration among patients receiving invasive ventilation and NIV with a helmet or a face mask. Using an in vitro lung model capable of simulating spontaneous breathing, gas flow and airway pressure were measured with varying positive end-expiratory pressure and pressure support levels. Wasted efforts were determined while lung compliance, respiratory rate (RR), continuous positive airway pressure (CPAP), and pressure support (PS) levels were changed. Delay times were more than twice as long with a helmet compared to facemask or invasive ventilation, but decreased during helmet ventilation with increasing CPAP and PS levels. During the initial inspiratory phase, PTP was smaller with helmet compared to facemask or invasive ventilation, but not so when a complete inspiration with PS was evaluated. Wasted efforts occurred earlier during helmet ventilation and were aggravated with rising PS, RR, and compliance. Although delay times are prolonged during helmet ventilation, PTP is initially smaller compared to facemask and invasive ventilation, indicating less work of breathing due to the high volume the patient can access. Increasing the CPAP or PS level decreases delay times in helmet ventilation and should therefore be considered whenever possible. Wasted inspiratory efforts occurred at higher RRs and should carefully be monitored during NIV.