Chest trauma remains an issue for health services for both severe and apparently mild trauma management. Severe chest trauma is associated with high mortality and is liable for 25% of mortality in multiple traumas. Moreover, mild trauma is also associated with significant morbidity, especially in patients with preexisting conditions. Thus, whatever the severity, a fast-acting strategy must be organized. In order to improve the prognosis of patients with severe chest trauma, early and continuous application of non-invasive mechanical ventilation (NIV) can indeed reduce the need for intubation and shorten intensive care unit length-of-stay. Among different mechanisms, the early use of positive end-expiratory pressure after chest trauma, when feasible, seems mandatory to optimize oxygenation and improve clinical outcomes. Indeed, interventions aimed at preventing ARDS after chest trauma carry the greatest potential to reduce the substantial morbidity, mortality, and resource utilization associated with this syndrome.

In the past years, High-flow nasal cannula oxygen (HFNC) has gained an important popularity among intensivest to manage patients with acute respiratory failure, filling a gap in the ventilatory support escalation between facemask oxygen and non-invasive or invasive mechanical ventilation. Interestingly, the use of HFNC was widely and rapidly adopted in ICUs.A unique feature of HFNC is its ability to comfortably deliver high flows of warmed humidified gas, 20-70 L min, with a FiO2 range of 0.21-1.0. Physiological responses to HFNC therapy include increases in airway pressure, end-expiratory lung volume (EELV), and oxygenation which are probably optimal with higher flows (60-70 L/min), while the effects on dead-space washout work of breathing, and respiratory rate may be obtained with intermediate flows (20-45 L/min).

Many studies have found that high flow nasal oxygen is much better tolerated by patients compared to non-invasive ventilation, which may improve compliance. Nevertheless, there is no clear consensus on the treatment outcomes (such as intubation rate, escalated respiratory support rate, and mortality) of high flow nasal oxygenation versus non-invasive ventilation for patients with traumatic chest injuries.

Inclusion Criteria:

• Rib fractures, pulmonary contusion, and admission within 24 h of injury
• Hypoxemia (SpO2 90 % while breathing 10 l/min oxygen in the ER), or hypercapnia (PaCO2 45 mm Hg) on study entry
• respiratory rate 25/ min despite an optimized intravenous analgesia
• No indication of mechanical ventilation at the time of admission to the intensive care unit

Exclusion Criteria:

• Patients < 18 years old
• Patient already admitted to ICU on mechanical ventilation
• requiring endotracheal intubation and mechanical ventilation immediately on admission for any cause
• facial fractures or base of skull fractures
• Who did not receive a chest computed tomography (CT) scan
• Glasgow Coma Scale ≤ 12