Abstract
BackgroundHigh-flow nasal cannula oxygen (HFNC) is a relatively new therapy used in adults with respiratory failure. Whether it is superior to conventional oxygen therapy (COT) or to noninvasive mechanical ventilation (NIV) remains unclear. The aim of the present study was to investigate whether HFNC was superior to either COT or NIV in adult acute respiratory failure patients.MethodsA review of the literature was conducted from the electronic databases from inception up to 20 October 2016. Only randomized clinical trials comparing HFNC with COT or HFNC with NIV were included. The intubation rate was the primary outcome; secondary outcomes included the mechanical ventilation rate, the rate of escalation of respiratory support and mortality.ResultsEleven studies that enrolled 3459 patients (HFNC, n = 1681) were included. There were eight studies comparing HFNC with COT, two comparing HFNC with NIV, and one comparing all three. HFNC was associated with a significant reduction in intubation rate (OR 0.52, 95% CI 0.34 to 0.79, P = 0.002), mechanical ventilation rate (OR 0.56, 95% CI 0.33 to 0.97, P = 0.04) and the rate of escalation of respiratory support (OR 0.45, 95% CI 0.31 to 0.67, P < 0.0001) when compared to COT. There was no difference in mortality between HFNC and COT utilization (OR 1.01, 95% CI 0.67 to 1.53, P = 0.96). When HFNC was compared to NIV, there was no difference in the intubation rate (OR 0.96; 95% CI 0.66 to 1.39, P = 0.84), the rate of escalation of respiratory support (OR 1.00, 95% CI 0.77 to 1.28, P = 0.97) or mortality (OR 0.85, 95% CI 0.43 to 1.68, P = 0.65).ConclusionsCompared to COT, HFNC reduced the rate of intubation, mechanical ventilation and the escalation of respiratory support. When compared to NIV, HFNC showed no better outcomes. Large-scale randomized controlled trials are necessary to prove our findings.Trial registrationPROSPERO International prospective register of systematic reviews on May 25, 2016 registration no. CRD42016039581.
Highlights
High-flow nasal cannula oxygen (HFNC) is a relatively new therapy used in adults with respiratory failure
HFNC has several advantages when compared to conventional oxygen therapy (COT): (1) the high-flow rates match the patient’s inspiratory flow rates, which creates a positive pressure effect [5, 6] and reduces the anatomic dead space [7]; (2) HFNC can deliver a predictable and constant Fraction of inspired oxygen (FiO2) [8]; (3) HFNC can increase the partial arterial pressure of oxygen (PaO2)/FIO2 ratio, which reduces the entrainment of room air and the dilution of oxygen [1, 2]; (4) the heated and humidified gas that is inhaled can improve mucociliary motion and sputum clearance [3, 9]; and (5) there is reduced upper airway resistance, reduced work of breathing [10] and improvement in thoraco-abdominal synchrony [11, 12]
The main finding of our study was that HFNC significantly reduced the rate of intubation, mechanical ventilation and escalation of respiratory support compared with COT in adult patients with respiratory failure, but there was no difference in mortality
Summary
High-flow nasal cannula oxygen (HFNC) is a relatively new therapy used in adults with respiratory failure. High-flow nasal cannula oxygen (HFNC) is a relatively new and increasingly used therapy in adults with acute respiratory failure [1]. Compared to HFNC, noninvasive mechanical ventilation (NIV) can create a much higher gas flow rate and positive airway pressure but is not comfortable and has many complications [23, 24]. A recently published meta-analysis showed no significant difference in mortality or intubation rates when HFNC was compared to COT and NIV [26]. Maitra et al included only six RCTs in their meta-analysis that compared only the prognosis of higher respiratory support, and found no significant difference between HFNC and either standard oxygen therapy or NIV [27]. The small number of studies included in the meta-analysis makes its application limited
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