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.

Primary outcomes

• Proportion of patients with treatment failure within 5 days after planned extubation [Within 5 days after planned extubation]: Treatment failure was defined as reintubation or escalation of respiratory support after planned extubation. Escalation of respiratory support included the need for non-invasive ventilation, rescue high-flow nasal cannula therapy in the conventional oxygen therapy group, or other clinically indicated escalation due to respiratory deterioration. Outcome assessment was based on bedside clinical monitoring, arterial blood gas analysis, respiratory status, neurological status, airway protection assessment, and ICU medical record review.

Secondary outcomes

• Proportion of patients requiring tracheostomy during ICU stay [From planned extubation through ICU discharge, assessed up to 30 days after planned extubation]: The proportion of patients who required tracheostomy after planned extubation. Tracheostomy was identified by review of ICU medical records, operative or procedure notes, and hospital documentation.
• Incidence of ventilator-associated pneumonia during ICU stay [From planned extubation through ICU discharge, assessed up to 30 days after planned extubation]: Ventilator-associated pneumonia was assessed by review of hospital medical records using predefined clinical, radiographic, and microbiological criteria, including clinical examination, chest radiograph findings, and microbiological culture results.
• Length of stay in the intensive care unit [From ICU admission through ICU discharge, assessed up to 30 days after ICU admission]: ICU length of stay was calculated using the recorded dates and times of ICU admission and ICU discharge from ICU charts and hospital medical records.
• Time from planned extubation to reintubation [From planned extubation through reintubation, assessed up to 5 days after planned extubation]: Time from planned extubation to reintubation was calculated from the recorded date and time of extubation to the recorded date and time of re-insertion of the endotracheal tube. Patients who were not reintubated were censored at 5 days after extubation.

Sex: All, ages: 16 Years to any

Inclusion Criteria:

* Patients aged 16 years or older.
* Admission to the Surgical Intensive Care Unit after neurosurgery for acute brain injury, including traumatic brain injury, intracerebral hemorrhage, subarachnoid hemorrhage, ischemic stroke, or other acute neurosurgical brain conditions.
* Requirement for invasive mechanical ventilation for at least 24 hours.
* Undergoing planned extubation after clinical assessment by the treating ICU team.
* Successful completion of a spontaneous breathing trial lasting 30 to 120 minutes.
* Adequate airway protection, defined as an Airway Care Score less than 8 points.
* Neurological readiness for extubation, as assessed by Glasgow Coma Scale score and bedside neurological examination.
* Adequate oxygenation before extubation, including PaO2/FiO2 greater than 200 mmHg and PEEP less than 7 cmH2O.

Exclusion Criteria:

* Pre-existing tracheostomy.
* Known upper airway obstruction, including airway stenosis or airway tumor.
* Suspected cerebrospinal fluid leak or complex skull base fracture.
* Unplanned self-extubation.
* Requirement for immediate prophylactic reintubation before initiation of post-extubation oxygen therapy.
* Requirement for non-invasive ventilation before initiation of the study exposure.
* Missing key clinical data required for outcome assessment or propensity score matching.