Statement on liquid medical oxygen supply and use

23 April 2020

On 1 April 2020 the MHRA released a Central Alerting System (CAS) notice about the risk of a sudden pressure drop in oxygen supply pipes if demand through multiple wall outlets exceeds the maximum capacity of the Vacuum Insulated Evaporator (VIE). The alert was triggered following reports of oxygen supply failures due to the increased use of oxygen during the COVID-19 crisis (e.g. use of ventilators, CPAP, NIV, face mask). Pipeline dimension, regulator size and flow-panel control determine the maximum flow rate possible from any system. Most systems deliver oxygen at 3000 l.min-1. Adiabatic cooling at times of rapid vaporisation leads to icing of the VIE which further reduces output.

A second CAS notice was released on 6 April 2020 reminding of the potential consequence of increased oxygen demands when using CPAP and high flow nasal oxygenation devices and the risk of supply failure. BOC provide information on maximising oxygen delivery by increasing system pressure and thereby flowrate. Careful management of the primary supply system is stressed.

Discussion with the relevant gas supplier will ensure the best performance of the bulk medical oxygen supply system.

ENDS