Summary: Stabilisation of the preterm infant in the delivery room using nasal high flow: A 5—year retrospective analysis.

Topic: Primary Support – Delivery Room

Siva, Naren V., and Peter R. Reynolds. Stabilisation of the preterm infant in the delivery room using nasal high flow: A 5—year retrospective analysis. Acta Paediatrica 2021; 110(7): 2065-2071. 

Siva and colleagues published the results from a retrospective observational cohort study in Acta Paediatrica in 2021, from a single center neonatal intensive care unit (NICU) reviewing clinical outcomes after initiating a routine policy of preterm respiratory stabilization using nasal high flow (HF) in the delivery room (DR). The study took place at St. Peter’s Hospital in the United Kingdom and included neonates born before 32 weeks of gestation with no exclusion criteria. The HF data was collected exclusively using Vapotherm high velocity therapy. Stabilization measures and outcomes were recorded including oxygen requirements, admission temperature, surfactant administration, invasive ventilation within 72 h of birth, bronchopulmonary dysplasia (BPD) and death. 

There were 491 eligible babies during the 5-year study period. There were four categories of treatment and outcomes into which the neonates were grouped as shown:   

  • Group A—stabilized by high velocity therapy (n = 292, 59%) 
  • Group B—stabilized by positive end-expiratory pressure (PEEP) mask (n = 85, 17%) 
  • Group C—intubated (n = 93, 19%) 
  • Group D—required only low flow oxygen (LFNC) or were self-ventilating in air (SVIA) (n = 21, 4%) 

292 infants were stabilized using high velocity therapy in the DR. The DR stabilization protocol used an initial flow setting of 7 and 7.5 L/min, with an initial fraction of inspired oxygen (FiO2) at 21%. Adjustments and weaning of flow and/or FiO2 were made by the attending clinician according to judgement of FiO2 and clinical stability. Escalation of respiratory support to biphasic positive airway pressure (BiPAP®) or mechanical ventilation was at clinician discretion and usually for poor respiratory effort and/or persistent respiratory acidosis. 45% of these babies received surfactant (Curosurf™) within the first 72hrs of treatment and of those, 93% received it via the less invasive surfactant administration method (LISA). 

Babies in Groups B & D were heavier and more mature by comparison to Group A. Group C contained the most premature babies with the lowest weights. 

The median admission temperature in babies transferred on high velocity therapy was 36.8°C, the median FiO2 at admission was 25%. At 72 postnatal hours, 69% of babies were still receiving high velocity therapy, and 9% were breathing in air or on low-flow nasal cannula (LFNC). 27% were intubated for mechanical ventilation within 7 days. Babies that required an escalation of respiratory support within 72 hours were more premature (26 + 5 weeks) and had lower birthweight (787 grams). At 36 weeks gestational age, 36% of survivors had BPD. 46% of the babies diagnosed with BPD were discharged from NICU without supplementary oxygen. The authors report that rates of invasive ventilation and other complications are similar to other published work using nCPAP1,2

Overall, the most premature neonates had the worst outcomes. The authors note that the babies who had to be intubated represented the sickest population in this study. They also point out that there were significant differences in outcomes for babies born before and after the 27 week mark and suggest that this could be an important benchmark in distinguishing neonatal populations rather than solely using <32 weeks as a denominator. 

The authors note that in the DR, nasal high-flow (high velocity therapy) stabilization in babies <32 weeks is associated with low rates of subsequent intubation and report that high velocity therapy may be an appropriate method for non-invasive respiratory stabilization in preterm babies. The authors caution extrapolating this result as there remains a need for further evaluation on the use of HF in the DR advocating that a randomized trial comparing DR stabilization using HF and CPAP would be useful to define optimal pathways. 

The clinical team in this trial have demonstrated that preterm babies <32 weeks can be effectively stabilized on high velocity therapy in the DR. The limitations for this report are that it is a retrospective, observational, single center study, with uncontrolled selection of babies into the groups, and statistical outcomes are weaker as a result. The clinical team in this study only used the Vapotherm Precision Flow®, and the findings may not be reproducible using other HF systems. In addition, the clinical team reported considerable experience in using HF for respiratory support in premature babies. Furthermore, during the observational period, the guidelines changed, including introducing the routine use of LISA instead of INSURE for surfactant and a lower FiO2 threshold (30%) for surfactant administration. 

Schmölzer GM, Kumar M, Pichler G, Khalid A, O’Reilly M, Cheung P. Non-invasive versus invasive respiratory support in preterm infants at birth: systematic review and meta-analysis. BMJ.2013;347:f5980. 
2.) Dargaville PA, Gerber A, Johansson S, et al. Incidence and Outcome of CPAP Failure in Preterm Infants. Pediatrics.2016;138(1):e20153985 

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