NHSEI issued an Urgent Patient Safety Notice regarding the “Use of high flow oxygen therapy devices (including wall CPAP, and high flow face mask or nasal oxygen) during the Coronavirus epidemic” on 31 March 2020 (NHSE/I – 2020/001). The alert required immediate action from all hospitals to mitigate the risk posed by the use of multiple high flow devices, and highlighted “If the demand through multiple wall outlets exceeds the maximum capacity of the VIE delivery system, there is a risk of a rapid pressure drop in oxygen supply pipes. This could lead to a failure of oxygen delivery systems throughout the hospital, including to patients on face masks, CPAP, ventilators and operating theatres. There is also a risk of rapid and unpredictable depletion of the VIE. Both of these situations present a potentially significant risk to multiple patients simultaneously.”

The ICS is aware of multiple hospitals that are currently experiencing significant burden on their oxygen infrastructure, and that in particular a major incident occurred at an East of England hospital yesterday due to compromise of their oxygen infrastructure. This was preceded by low-pressure alarms (as seen at other sites) and in an urgent need to evacuate ICU patients to nearby NHS Trusts.

We also know that several hospitals have tested their oxygen infrastructure and found their ability to use multiple high-flow devices simultaneously is less than expected given their VIE capacity and pipework.

We strongly encourage all institutions to pay close attention to the actions required in the UPSN, specifically:

Urgently ensure liaison between clinicians and hospital oxygen engineering teams to ascertain:

• the maximum flow rate from your VIE
• any additional limitations to oxygen delivery owing to pipework architecture
• calculate the maximum number of patients who can be treated with high flow devices such as wall CPAP and communication of this to the relevant clinical teams
• undertake a daily count of the number of high-flow systems where the potential oxygen flow rate exceeds 10 L/min (this will include most wall CPAP systems, High Flow Nasal Oxygen (HFNO), some non-invasive ventilators used in acute settings, and many ventilators used in critical care units or operating theatres).
• implement safety measures to prevent accidental O2 system failure (such as limiting the number of these devices available for clinical use).

In addition, we wish to highlight that should your hospital oxygen system develop “low oxygen pressure alarms” in the context of high-flow device usage, this is likely to be an early indication of approaching flow limitation and urgent action should be taken to review the usage of these devices, reduce demand on the oxygen infrastructure, and urgently escalate for oxygen engineering assistance.

With well wishes

Dr Ganesh Suntharalingam

President, Intensive Care Society