MEDICAL GAS SYSTEMS
Oxygen flow testing vital in ensuring system resilience
Concerns around oxygen supply have dogged the response to COVID-19 for hospital Trusts around the UK. Many systems have struggled to deliver the flow capacity required to meet demand from the high numbers of patients requiring ventilation, highlighting the necessity for an effective oxygen flow testing strategy. Since March 2020, healthcare engineering specialist, MIG Medical Installations, has conducted more than 20 oxygen flow capacity tests for 12 hospitals throughout the UK. Here, managing director, Anthony Mitten, details the importance of site-wide testing, and the impact it can have on contingency planning when high demand is placed on a piped oxygen delivery system.
A Project manager from MIG inspecting an Amal jet probe.
Of the challenges facing healthcare estates teams in the last year, few have been more significant than maintaining oxygen flow pressure in systems facing unprecedented demand. In the past 12 months, MIG Medical Installations has conducted oxygen capacity flow tests in hospitals in Oxford, in Wigan, in Wrightington, at The Countess of Chester, in Aintree, at the Liverpool Heart and Chest Hospital, and in Lancaster and Morecambe Bay.
Throughout this time, it was clear that some pipelines were struggling to deliver the required flow capacity without significant modification. From bottlenecks, to pipework with insufficient diameters, the number of impediments only served to reinforce just how important it is to have a robust testing strategy in place.
In August 2020, the NHSI COVID-19 Working Group published guidelines for healthcare estates teams that included recommended actions to mitigate the effect of the pandemic on their oxygen pipeline. The guide suggested tasks ranging from documenting maximum
64 Health Estate Journal June 2021
Insertion of the probe into an oxygen valve to simulate use.
flow capacities and limitations, to carrying out load testing, and ensuring that ‘as- fitted’ drawings are up to date. The timing of these recommendations provided a small margin of time to allow Trusts to prepare for the second wave. Ironically, they are also the same actions that we have been taking with hospitals since the beginning of the pandemic, with some notable exceptions.
Taking a site-wide approach to load testing
The NHSI guidance recommended testing a single ward or department. However, depending on a hospital’s COVID-19 plan, flow may be directed not just into areas where patients are most in need, but also to wards and theatres designated as contingency areas. Without a site-wide test, it becomes impossible for the Estates Department to learn whether this would starve other wards of the oxygen they require. To properly calculate usage, it is necessary to test whether each area can simultaneously meet the required flow rate.
Of course, maintaining patient safety is
the primary, overriding factor, which is why we use a trained team of engineers and run a full risk assessment prior to starting any test, and, because we test individual wards first before conducting a site-wide test, we are already aware of any individual performance issues that we may need to mitigate. We also discuss the method of test and flow recommendations with clinicians, Authorised Persons, and anaesthetists, prior to starting, and we work with the AP to ensure that every source of supply is completely full, from the VIE, to the stand-by manifolds. Naturally, a site-wide test will result in a significant amount of oxygen usage.
Total site flow test
Next, we conduct a total site flow test under controlled conditions, with the site APs and our team of engineers continually monitoring and recording the flows and pressures to 3.5 bar. Each engineer is in constant contact with the test control engineer, with all point of supply VIEs continuously monitored as well. In the hospitals we tested, the initial required rates ranged from 60 litres/min
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