Helmet NIV vs. CPAP vs. High-flow Nasal Oxygen in Hypoxemic Respiratory Failure

The optimal initial management of acute hypoxemic respiratory failure is uncertain. Helmet noninvasive ventilation and high-flow nasal oxygen appear as the most promising techniques in this setting. Recently, the first head-to-head randomized trial compared first-line continuous treatment with helmet pressure support ventilation with specific settings (PEEP=12 cmH2O pressure and pressure support=10-12 cmH2O) vs. high-flow nasal oxygen alone in patients with moderate-to-severe hypoxemic respiratory failure. Results showed no significant inter-group difference in the days free of respiratory support at 28 days, but lower intubation rate and increased 28-day invasive ventilation-free days in the helmet group. Use of helmet noninvasive ventilation is less frequent than use of helmet continuous positive airway pressure, which is simpler to use.

The investigators designed an open-label, multicentre randomized trial to assess the effect of helmet pressure support ventilation and continuous airway pressure as compared to high-flow nasal oxygen on the intubation rate of patients with moderate-to-severe hypoxemic respiratory failure in the intensive care unit.

Inclusion criteria

• Acute symptoms of respiratory failure PaO2/FiO2 ratio ≤ 200; PaCO2≤45mmHg; Absence of history of chronic respiratory failure or moderate to severe cardiac insufficiency (NYHA>2 or left ventricular ejection fraction<50%); Informed consent

Patients that have already received NIV, CPAP continuously for more than 24 hours before the screening visit will be excluded.

Other Exclusion Criteria:

• Pregnancy;
• Exacerbation of asthma or chronic obstructive pulmonary disease;
• Hypercapnia (PaCO2>45 mmHg) with or without respiratory acidosis;
• More than 2 organ failures, including the lung.
• Documented pneumothorax;
• Clinical diagnosis of Cardiogenic pulmonary edema;
• Haemodynamic instability (Systolic blood pressure<90 mmHg or mean arterial pressure<65mmHg) and/or lactic acidosis (lactate>5 mmol/L) and/or clinically diagnosed Shock requiring administration of vasoactive agents (norepinephrine>0.1 mcg/Kg/min);
• Metabolic Acidosis (pH <7.30 with normal- or hypo-carbia);
• Chronic kidney failure requiring dialysis before ICU admission;
• Chronic hypoxemic respiratory failure requiring long-term oxygen therapy;
• Altered neurological status that requires immediate intubation and/or making the patient uncooperative;
• Urgent need for endotracheal intubation, according to the decision of the attending physician;
• Do not intubate order;
• Decision of withdrawal of life-sustaining therapy;
• Thoracic or abdominal surgery in the previous 7 days;
• Any condition that makes the patient very likely to require endotracheal intubation due to a reason different from respiratory failure;
• Recent head surgery or anatomy that prevent the application of helmet or HFNC to patient's face.