High-flow nasal cannula oxygen therapy better than CPAP in preterm infants

Compared with continuous positive airway pressure (CPAP), respiratory support using high-flow nasal cannula oxygen therapy (HNFC) appears to yield better clinical outcomes in preterm infants, according to a recent meta-analysis.

However, further studies are still needed to confirm these findings, particularly when using HNFC as a primary respiratory support option.

Twenty-seven eligible studies were included in the meta-analysis, contributing a total of 3,351 patients, of whom 1,664 were treated with HNFC and 1,687 with CPAP. The quantitative synthesis compared HNFC against CPAP according to the primary outcomes of treatment failure and need for mechanical ventilation.

Pooled analysis of 22 studies revealed that HNFC and CPAP yielded comparable rates of respiratory support failure (risk ratio [RR], 1.17, 95 percent confidence interval [CI], 0.88–1.56). The same was true for the rate of mechanical ventilation (RR, 1.00, 95 percent CI, 0.84–1.19). [Front Pediatr 2022;doi:10.3389/fped.2022.980024]

“Both the HFNC and CPAP could provide positive pressure to help [dilate] the airway at an oxygen flow rate over 2 L/min,” the researchers said. However, the pressure output of HNFC can be affected by several factors such as gas flow, trachea diameter, and the newborns’ body weight, which could make accurate assessment of the pressure generated difficult.

In the present meta-analysis, there was considerable variation in these factors among the studies included, particularly as regards birth weight and HFNC flow rate, the researchers added. These contributed to the heterogeneity of the evidence and could have affected the obtained pooled estimates. Future studies to control for this heterogeneity are needed.

Signals of efficacy

Beyond the primary efficacy endpoints, HFNC outperformed CPAP in terms of several secondary outcomes. For instance, infants on HFNC initiated mechanical ventilation much later than CPAP comparators (standardized mean difference [SMD], 0.60, 95 percent CI, 0.21–0.99).

Moreover, oxygen therapy ran for a significantly shorter time in the HFNC vs CPAP group (SMD, –0.35, 95 percent CI, –0.68 to –0.02), while the timing of enteral feeding was earlier in HFNC infants (SMD, –0.54, 95 percent CI, –0.95 to –0.13).

Meanwhile, age at respiratory failure onset, duration of mechanical ventilation, duration of respiratory support, time to exclusive breast feeding, or length of hospital stay did not differ between the two treatment arms. Death likewise occurred at comparable rates between HFNC and CPAP.

In terms of safety, HFNC led to a significantly lower rate of air leaks (RR, 0.65, 95 percent CI, 0.46–0.92) and nasal trauma (RR, 0.36, 95 percent CI, 0.29–0.45) than CPAP. The incidence of abdominal distension was likewise significantly lower in the former group (RR, 0.39, 95 percent CI, 0.27–0.58).

“Compared with CPAP, the use of HFNC for preterm infants might be more effective in reducing the use of mechanical ventilation and oxygen therapy,” the researchers said.

However, due to important limitations in the present study, “for premature infants with gestational age <28 weeks, the use of HFNC as the primary respiratory support still needs to be further elucidated,” they added.