High-flow oxygen therapy in tracheostomized patients at high risk of weaning failure

Abstract

PurposeHigh-flow oxygen therapy delivered through nasal cannulae improves oxygenation and decreases work of breathing in critically ill patients. Little is known of the physiological effects of high-flow oxygen therapy applied to the tracheostomy cannula (T-HF). In this study, we compared the effects of T-HF or conventional low-flow oxygen therapy (conventional O2) on neuro-ventilatory drive, work of breathing, respiratory rate (RR) and gas exchange, in a mixed population of tracheostomized patients at high risk of weaning failure.MethodsThis was a single-center, unblinded, cross-over study on fourteen patients. After disconnection from the ventilator, each patient received two 1-h periods of T-HF (T-HF1 and T-HF2) alternated with 1\xa0h of conventional O2. The inspiratory oxygen fraction was titrated to achieve an arterial O2 saturation target of 94–98% (88–92% in COPD patients). We recorded neuro-ventilatory drive (electrical diaphragmatic activity, EAdi), work of breathing (inspiratory muscular pressure–time product per breath and per minute, PTPmusc/b and PTPmusc/min, respectively) respiratory rate and arterial blood gases.ResultsThe EAdipeak remained unchanged (mean\u2009±\u2009SD) in the T-HF1, conventional O2 and T-HF2 study periods (8.8\u2009±\u20094.3\xa0μV vs 8.9\u2009±\u20094.8\xa0μV vs 9.0\u2009±\u20094.1\xa0μV, respectively, p\u2009=\u20090.99). Similarly, PTPmusc/b and PTPmusc/min, RR and gas exchange remained unchanged.ConclusionsIn tracheostomized patients at high risk of weaning failure from mechanical ventilation, T-HF did not improve neuro-ventilatory drive, work of breathing, respiratory rate and gas exchange compared with conventional O2 after disconnection from the ventilator. The present findings might suggest that physiological effects of high-flow therapy through tracheostomy substantially differ from nasal high flow.