Effectiveness of non-invasive ventilation in acute respiratory failure of obese patients: a brief narrative review

Non-invasive ventilation (NIV) has been used successfully for the management of acute respiratory failure (ARF) more often in the last two decades compared to prior decades; nevertheless, NIV can have failure rates ranging from 5% to 50%. However, there are particular groups of patients that are more likely to benefit from NIV. One of these groups is patients with hypoventilation syndrome (OHS). The aim of this review is to seek evaluation of the effectiveness of NIV in acute setting. Only a few studies have investigated NIV success or failure in OHS patients. More than 30% of them were diagnosed when hospitalized for ARF. NIV rarely failed in reversing ARF. OHS patients who exhibited early NIV failure had a high severity score and a low HCO₃ level at admission; more than half of hypercapnic patients with decompensated OHS exhibited a delayed but successful response to NIV. Patients with decompensation of OHS have a better prognosis and response to NIV than other hypercapnic patients. They require more aggressive NIV settings, a longer time to reduce PaCO₂ levels, and more frequently a delayed but successful response to NIV.