Physiologic Effects of High-flow Nasal Cannula Versus Standard Oxygen Therapy Postextubation in Critically Ill Patients

Summary

High-flow nasal cannula (HFNC) is a rather novel system to provide oxygen therapy, which provides flows up to 60 liters/minute (LPM) of heated and humidified gas through nasal prongs. HFNC is increasingly being used in patients with acute respiratory failure. In healthy volunteers and in patients with acute respiratory failure it has been shown to induce several effects beyond those expected for a standard oxygen therapy, such as increased carbon dioxide (CO2) clearance and positive airway pressure.

One of the potential indications for HFNC is to facilitate weaning from mechanical ventilation and extubation. As weaning failure is one of the most complex challenges in mechanically ventilated patients, the use of HFNC after extubation, in order to prevent reintubation, has been evaluated in some clinical trials, with promising results. However, the role of HFNC postextubation is still controversial, and information regarding its effects on the pathophysiologic mechanisms of weaning failure is lacking.

The goal of this proposal is to compare the acute physiologic effects of postextubation HFNC versus standard oxygen therapy, in critically ill patients, on relevant mechanisms related to weaning failure: work of breathing, lung function, systemic hemodynamics.

This will be a randomized crossover study which will include critically ill mechanically ventilated patients, who fulfill criteria indicating they may be ready for weaning from mechanical ventilation, and in whom a spontaneous breathing trial (SBT) is planned to determine if they should be extubated. After checking eligibility and obtaining informed consent, patients will be monitored with an esophageal catheter (esophageal / gastric pressures to determine work of breathing, and electric activity of diaphragm to determine neuromechanical coupling), and a noninvasive ventilation monitor (electric impedance tomography to assess global and regional ventilation). Work of breathing, lung function, and systemic hemodynamics will be assessed during the SBT. Inclusion in the study will be confirmed only if they pass the SBT and are extubated. During the first 2 hours after extubation patients will undergo one hour of HFNC and one hour of standard oxygen therapy, with the crossover sequence being randomized previously at the time of inclusion, and with assessments repeated at the end of each treatment period.

Conditions

• Ventilator Weaning

Interventions

DEVICE

High flow nasal cannula

High flow nasal cannula will be provided through a commercial device (AIRVO2 + Optiflow nasal cannula, Fisher \& Paykel), at 50 LPM and at the same FiO2 applied during the spontaneous breathing trial.

DEVICE

Standard oxygen therapy

Standard oxygen therapy will be provided through a Venturi mask and O2 flow will be adjusted to keep the same FiO2 applied during the spontaneous breathing trial.

Sponsors & Collaborators

• Fondo Nacional de Desarrollo Científico y Tecnológico, Chile

  collaborator OTHER_GOV

• Pontificia Universidad Catolica de Chile

  lead OTHER

Principal Investigators

• Alejandro Bruhn, MD, PhD · Pontificia Universidad Catolica de Chile

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2021-01-27

Primary Completion

2022-11-17

Completion

2022-12-17

Countries

• Chile

Study Locations