High-Flow Nasal Cannula After Extubation in Acute Brain Injury

Extubation failure is a clinically important complication in patients with acute brain injury after neurosurgery. These patients may have impaired consciousness, weak cough, reduced airway protection, and limited respiratory reserve, which can increase the risk of reintubation and other postoperative pulmonary complications. High-flow nasal cannula provides heated and humidified oxygen at high flow rates and may improve oxygenation, reduce work of breathing, and support airway clearance after extubation.

This study was designed as a prospective observational cohort study conducted in the Surgical Intensive Care Unit of Bach Mai Hospital. Adult patients aged 16 years or older who were admitted after neurosurgery for acute brain injury, required invasive mechanical ventilation for at least 24 hours, successfully completed a spontaneous breathing trial, had adequate airway protection, and underwent planned extubation were consecutively enrolled. The choice of post-extubation oxygen therapy was not assigned by the investigators. Patients received either HFNC or conventional oxygen therapy according to the attending ICU physician's clinical decision and routine ICU practice.

In the HFNC group, HFNC was initiated immediately after planned extubation when selected by the treating physician. The initial flow rate was 60 L/min, and FiO2 was titrated to maintain SpO2 between 95% and 100%. HFNC was planned for at least the first 24 hours after extubation and was subsequently weaned according to clinical tolerance. In the conventional oxygen therapy group, oxygen was delivered through a standard nasal cannula or face mask, with oxygen flow adjusted to maintain the same SpO2 target.

Clinical data, respiratory parameters, neurological status, arterial blood gas results, oxygen therapy settings, escalation of respiratory support, reintubation, tracheostomy, ventilator-associated pneumonia, duration of mechanical ventilation, and ICU length of stay were collected from ICU medical records, bedside monitoring charts, and nursing or respiratory therapy documentation.

The primary outcome was treatment failure, defined as reintubation or escalation of respiratory support within 5 days after extubation. Secondary outcomes included tracheostomy during ICU stay, ventilator-associated pneumonia, ICU length of stay, total duration of mechanical ventilation, and time from extubation to reintubation. Propensity score matching was performed to reduce selection bias between the HFNC and conventional oxygen therapy groups. Matching variables included age, sex, body mass index, diagnosis category, Glasgow Coma Scale score, airway protection status, duration of mechanical ventilation, and baseline gas exchange variables.