Abstract
Background Humidified high-flow nasal cannula (HHFNC) has become an increasingly common treatment modality, used to provide respiratory support for bronchiolitis patients. In our UK paediatric unit, we have seen the proportion of bronchiolitis patients receiving HHFNC increase from 3% in 2016/17 to 13% in 2017/18 to 21% in 2019/20. However, at the time of initiating this project, guidelines on how HHFNC weaning should be performed were not provided at a local or national level. This is of particular importance in the current SARS CoV-2 pandemic as HHFNC is categorised as an aerosol generating procedure, so it is advantageous to minimise the length of time patients spend on HHFNC through efficient weaning.
Objectives We investigated how efficiently patients were weaned from HHFNC, and whether providing a specific weaning plan was associated with more efficient weaning.
Methods The medical records of all patients presenting to our centre under 1 year of age diagnosed with bronchiolitis between 01/10/2019 and the 11/02/2020 were reviewed (n=70). Of these, 14 patients (20%) were placed on HHFNC for longer than 3 hours. For these patients, we calculated the total length of time on HHFNC and time taken to wean from HHFNC. We then assessed whether a specific weaning plan was documented for each patient, judging a specific weaning plan to be one in which there were instructions as to how the flow rate or fraction of inspired oxygen (FiO2) should be reduced with respect to time.
Results The median time spent on HHFNC was 2.1 days. A median of 1.0 day was spent weaning from HHFNC, however there was a large range in weaning time, from 3.5 hours to 4.0 days. We found specific weaning plans were documented for 4 patients. Patients who had a specific weaning plan documented were weaned from HHFNC more quickly (mean = 14.75 hours) than those who did not (mean = 34.6 hours); Welch’s t-test, t(11.93) = 2.26, p = 0.043.
Conclusions This project showed a high proportion of time spent on HHFNC, in our unit, was spent weaning. It provided evidence that weaning can be more efficient when specific guidance is provided. Therefore, we created new Trust guidelines for standardised HHFNC weaning in bronchiolitis patients. These guidelines are in-line with the RCPCH guidance published on the 18/09/2020, in light of concerns about HHFNC and its classification as an aerosol generating procedure. It is planned to repeat the data collection for the 2020/21 bronchiolitis season to assess whether this new guidance both improves the efficiency of HHFNC weaning whilst remaining safe. However, this may be challenging with the unusually low rates of bronchiolitis we are seeing so far this season!