• humidified, high flow nasal cannula
• continuous positive airway pressure
• United Kingdom

Humidified high flow nasal cannula (HHFNC) has gained popularity in neonatal care. A systematic review1 of the results of nine trials, which included a total of 1112 infants, however, demonstrated that HHFNC was not superior to other modes of non-invasive ventilation in infants of >28 weeks gestational age. We, therefore, sought to determine whether clinical practice regarding HHFNC had changed since 2012 when all UK units were surveyed2 and also to identify why practitioners preferred HHFNC or continuous positive airway pressure (CPAP).

In 2015, lead clinicians of all 194 UK neonatal units were identified from the National Neonatal Audit Programme, British Association of Perinatal Medicine directory and a departmental database from previous audits. In 2012, practitioners from the then 203 UK neonatal units had been contacted.2 Both surveys included questions on the level of neonatal care, the indications for use of HHFNC and the flow rates used. The 2015 survey also contained questions regarding nasal prong size, weaning policies and HHFNC or CPAP preference (practitioners were given a list of possible reasons to choose from).

There was 100% response rate to both surveys. Use of HHFNC was significantly increased in 2015 compared with 2012 (p<0.001) (table 1). Almost all local neonatal and neonatal intensive care units were using HHFNC in 2015. Fewer units were using HHFNC as an alternative to CPAP or weaning from CPAP (p=0.001), but a greater proportion were using it as the primary support mode post extubation (p=0.001). The 2015 survey highlighted that in 25% of units, the prong size was chosen to fit snugly and occlude the nostril, whereas it is recommended that the fit should be <50% of the nares.3 Thirty-six per cent of units were using HHFNC without guidelines. The highest and lowest flow rates used varied in both surveys, but the magnitude of change of flow when weaning from HHFNC did not differ significantly in the two surveys. In the 2015 survey, weaning the flow in increments of between 0.5 and 1 L/min and 24 hourly was most popular, but there was no consensus. This likely reflects that there is currently no evidence to determine the best weaning strategy from HHFNC.4

The majority of practitioners preferred HHFNC (table 2). In particular, almost all thought babies achieved full oral feeds by breast or bottle quicker on HHFNC and that it was more comfortable for the baby than CPAP.