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

Tania Stripoli,Paolo Trerotoli,Francesco Bruno,Rachele Iannuzziello,Rosa Di Mussi,Francesco Staffieri,Francesca De Carlo,Fabio Sechi,Carlo Alberto Volta,Salvatore Grasso,Luigi Camporota,Paola Pierucci,Savino Spadaro

doi:10.1186/s13613-019-0482-2

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 h 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 ± SD) in the T-HF1, conventional O2 and T-HF2 study periods (8.8 ± 4.3 μV vs 8.9 ± 4.8 μV vs 9.0 ± 4.1 μV, respectively, p = 0.99). 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.

Highlights

High-flow nasal cannula oxygen therapy is the administration of a warmed and humidified air/oxygen mixture at a flow rate between 20 and 60 L/min [1] through nasal cannulae (HFNC)
Since HFNC decreases the risk of re-intubation in patients at risk of extubation failure [6, 7], it is reasonable to hypothesize that T-HF could aid the separation from mechanical ventilation in mechanically ventilated, tracheostomized patients at high risk of weaning failure
The CONSORT study diagram (Fig. 3) shows that in the study period, 22 out of 38 tracheostomized patients with prolonged weaning from mechanical ventilation at high risk of weaning failure were eligible for the study and 14 were enrolled and completed the study protocol

Summary

Introduction

High-flow nasal cannula oxygen therapy is the administration of a warmed and humidified air/oxygen mixture at a flow rate between 20 and 60 L/min [1] through nasal cannulae (HFNC). Compared with conventional oxygen therapy (conventional O 2), HFNC produces several physiological effects [9], which include: a better matching between the delivered gas flow mixture and patient’s spontaneous inspiratory flow; a positive endexpiratory pressure (PEEP) effect (generally between 2 and 8 cm H 2O [10, 11]) and a “CO2 wash out” effect from the upper airways [12, 13]. Since HFNC decreases the risk of re-intubation in patients at risk of extubation failure [6, 7], it is reasonable to hypothesize that T-HF could aid the separation from mechanical ventilation in mechanically ventilated, tracheostomized patients at high risk of weaning failure.

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Conclusion