Alternative sources for high flow nasal oxygen in low-resource settings: Exploring the potential of auxiliary oxygen ports and wall flowmeters

Background

High flow nasal oxygen (HFNO) therapy delivers pure oxygen at rates over 40 L/min during preoxygenation and 60 L/min during apnoea, preventing hypoxia and extending safe apnoeic time. HFNO is beneficial in certain clinical scenarios. However, cost and limited availability of HFNO devices restrict routine use. Auxiliary oxygen outlets on anaesthesia workstations present a potential alternative HFNO source.

Aim

This study aimed to assess the maximum flow rates from auxiliary oxygen outlets on various anaesthesia workstations and wall flowmeters, to explore their viability as a source for HFNO.

Methods

After calibration in Switzerland, a CITREX H4 gas flow analyser was used to measure flow rates across multiple anaesthesia workstations and wall-mounted flowmeters at five hospitals affiliated with one academic anaesthesia department.

Results

Only two of nine tested workstations could reliably support flows sufficient for high flow apnoeic oxygenation. The General Electric (GE) CS 650 workstation had the highest average flow rate (120 L/min) while the Dräger Fabius GS Premium had the lowest (13 L/min). Wall flowmeters had flow rates ranging from 108 to 28 L/min, with most supporting flow rates greater than 60L/min.

Conclusion

The auxiliary oxygen outlet on anaesthetic workstations and general oxygen flowmeters is underutilised. Sufficient flow rates to function as a source of HFNO are attainable with many types, but should be individually tested. In a resource-limited environment, this could provide a cost-effective alternative in providing apnoeic oxygenation for a time-limited period, although safety has not yet been established.