In patients with acute hypoxemic respiratory failure (AHRF), High Flow Nasal Therapy (HFNT) improves oxygenation, tolerance, and decreases work of breathing as compared to standard oxygen therapy by facemask. The hypothesis is that this flow challenge (ROX index variation from 30 to 60L/min) could be used as a test for assessing changes in lung aeration, analyzed by the variation in end expiratory lung volume (ΔEELV), in patients treated with HFNC. It may allow to personalize the flow settings during HFNC. In this sense, an increase in EELV will be observed with higher flows in responders and, therefore, these participants may benefit from increasing the flow. In contrast, to increase the flow in non-responders (no significant increase in EELV with higher flows) increase the risk of patient self-inflicted lung injury (P-SILI).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
26
Flow will be set at 30L/min, FiO2 will be adjusted manually to maintain SpO2within the target range
Flow will be set at 45L/min, FiO2 will be adjusted manually to maintain SpO2within the target range
Flow will be set at 60L/min, FiO2 will be adjusted manually to maintain SpO2within the target range
Hospital Universitari Vall d'Hebron
Barcelona, Spain
RECRUITINGTo validate the correlation between the change in ROX index and the change in EELV
Change in ROX is defined as the difference in ROX index (SpO2/FiO2/respiratory rate) between 2 flows. Change in EELV is the difference in End-Expiratory Lung Volume as determined by EIT.
Time frame: 20 minutes
To assess the changes in aeration distribution (by the variable center of ventilation (CoV)) measured by EIT at different flows (30L/min, 45 L/min and 60L/min).
Lung aeration as defined by the variable center of ventilation (CoV) in EIT.
Time frame: 20 minutes
To assess the changes in lung homogeneity (by the variable global inhomogeneity index (GI)) measured by EIT at differents flows (30L/min, 45 L/min and 60L/min).
Lung homogeneity as defined by global inhomogeneity index (GI) by EIT
Time frame: 20 minutes
To analyze the differences in SpO2 at different flows
SpO2 by pulseoxymetry
Time frame: 20 minutes
To analyze the differences in respiratory rate at different flows
Breaths/minute
Time frame: 20 minutes
To analyze the differences in the FiO2 used at different flows
FiO2 will be titrated manually to achieve a predefined SpO2 range (92 - 96%; 88-92% for patients with chronic respiratory disease)
Time frame: 20 minutes
To analyze the differences in patient comfort at different flows, using the visual analogic scale (from 0 to 10)
Comfort score by visual analogic scale. From 0 (worst outcome) to 10 (best outocome).
Time frame: 20 minutes.
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