Postextubation High-Flow Nasal Cannula Oxygen, Randomized Trial of an ICU Quality Improvement Intervention, and Midodrine during Recovery from Septic Shock

Abstract

Even with careful patient selection, up to 20% of patients develop post-extubation respiratory failure and require reintubation (2). Prophylactic noninvasive positive pressure ventilation after extubation has been found to improve outcomes, including all-cause mortality, although this benefit appears restricted to patients at high risk for post-extubation respiratory failure (3) and those with chronic respiratory disorders who develop hypercapnia during a trial of spontaneous breathing (4, 5).There is increasing interest in the potential benefits of delivering humidified and heated oxygen by high-flow nasal cannula (HFNC) (6, 7). HFNC increases end-expiratory lung volume, reduces nasopharyngeal dead space, decreases work of breathing, facilitates clearance of respiratory secretions, and enhances patient comfort (8). In a recent trial, post-extubation use of HFNC in patients at high risk of post-extubation respiratory failure (identified by a Pa O 2 /FI O 2 ratio less than 300 at the end of a spontaneous breathing trial) resulted in better oxygenation than oxygen supplementation by Venturi mask and reduced the need for reintubation, although the latter was only a secondary endpoint of the study (9).The trial by Hernández and colleagues tested whether the prophylactic use of HFNC compared with conventional oxygen therapy after extubation reduced the need for reintubation in patients at low risk of post-extubation respiratory failure (1). Ten inclusion criteria were used to identify low-risk patients, including: age younger than 65 years; absence of heart failure as the primary indication for mechanical ventilation; absence of moderate to severe chronic obstructive pulmonary disease; Acute Physiology and Chronic Health Evaluation II score less than 12 on the day of extubation; body mass index less than 30 kg/m 2 ; and less than 2 comorbidities. A total of 527 subjects were ultimately enrolled in the study. Immediately after extubation, subjects were randomized to either HFNC for 24 hours (with flow uptitrated at 5 L/min intervals to the point of patient discomfort) or conventional oxygen applied through a facemask or nasal cannula. The primary outcome was need for reintubation at 72 hours. The use of HFNC significantly reduced the need for reintubation at 72 hours (4.9% vs. 12.2%; P = 0.004), with a number needed to treat of 14 to prevent 1 reintubation. Subjects treated with HFNC also had lower rates of reintubation secondary to respiratory causes (8.3% vs. 14.4%; P = 0.03).Although the results of the trial are provocative, several limitations deserve mention. Most subjects enrolled in the study had primary neurological or surgical diagnoses, whereas only a minority (16.5%) were admitted with primary respiratory failure. It was not clear that a similar benefit to HFNC would have been observed if the trial included a larger cohort of subjects with medical causes of respiratory failure. Similarly, the most common respiratory cause for reintubation with conventional oxygen therapy was the inability to clear secretion...