Acta Pædiatrica ISSN 0803-5253
REVIEW ARTICLE
Review finds insufficient evidence to support the routine use of heated, humidified high-flow nasal cannula use in neonates S Shetty, A Greenough (
[email protected]) Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King’s College London, London, UK
Keywords Continuous positive airways pressure, Heated humidified high-flow nasal cannula, Neonates, Oxygen, Respiratory support Correspondence Professor Anne Greenough, NICU, 4th Floor Golden Jubilee Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK. Tel: +44 203 299 3037 | Fax: +44 203 299 8284 | Email:
[email protected]
ABSTRACT A literature review was carried out following concerns about the use of heated, humidified, high-flow nasal cannulae (HHFNC) in premature infants. Randomised trials following extubation showed that HHFNC was associated with similar or greater reintubation rates than nasal continuous positive airway pressure, but significantly better nasal trauma scores. Infections with Ralstonia bacteria were an issue. Conclusion: There is insufficient evidence to support the routine use of HHFNC for premature infants and further research is required.
Received 18 February 2014; revised 16 April 2014; accepted 15 May 2014. DOI:10.1111/apa.12695
INTRODUCTION During heated, humidified, high-flow nasal cannula (HHFNC), heated and humidified gas is delivered at highflow rates between 1–8 L/min via nasal cannulae. It has been suggested that HHFNC may be effective by eliminating the dead space (1), reducing the work of breathing (2), improving lung compliance at higher flow rates (2) and delivering some degree of continuous positive airway pressure (CPAP) (1,3). There are, however, concerns about the unpredictability of the positive airway pressures generated (4–6) and the possibility of increased risk of infection, particularly due to Ralstonia spp. (7) and gram-negative organisms (8). Nevertheless, the technique has become popular, with 63% of units in Australia and New Zealand reportedly using HHFNC in 2010 (9). A survey of 214 neonatal units in the UK, with a 100% response rate, highlighted that 55% of units used high-flow oxygen therapy (flow rate >1.0 L/min) (10). In addition, in 2013, a survey of
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57 level two or three neonatal units in the UK reported that HHFNC was used in 77% of units (11). The survey highlighted that HHFNC was used mainly as an alternative to, or weaning from, CPAP and following extubation, but many other uses were reported (11). HHFNC was perceived to be easier to use and allow greater access to the baby. It
Key notes
A literature review was carried out following concerns about the use of heated, humidified, high-flow nasal cannulae (HHFNC) in premature infants. Randomised trials following extubation showed that HHFNC was associated with similar or greater reintubation rates than nasal continuous positive airway pressure, but significantly better nasal trauma scores. There is insufficient evidence to support the routine use of HHFNC for premature infants and further research is required.
©2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. 898–903
Shetty and Greenough
was demonstrated, however, that 39% of units used HHFNC without policies. The authors of the survey concluded that the current use of HHFNC appeared to be without clear criteria and mostly based on individual preference and that there was an urgent need for research to evaluate its use in newborns. Our aim, therefore, was to critically review the literature to determine whether there was sufficient evidence to support the routine use of HHFNC in certain circumstances for prematurely born infants.
DELIVERY OF DISTENDING PRESSURE The distending pressure delivered by HHFNC is dependent on prong size. There have been several attempts to produce a formula to calculate the pressure generation during HHFNC at different flow rates on the basis of infant weight, but inconsistent results have been produced (1,12). Airway pressure increases with the nasal prong to nares ratio (13). In an in vitro system (5), and in 18 infants (14), the pressure increased with increased flow (5). In 15 patients with respiratory distress syndrome (RDS), the presence of a leak as small as 30% reduced the pressure to
