HOSPITAL OXYGEN SYSTEMS


Findings and recommendations To assess a hospital’s O2


system, the


following steps are recommended: n Firstly, it is necessary to understand the existing O2 levels:


infrastructure at different


•Site – the hardware of the VIE needs to be assessed for any potential throughput bottlenecks which might be in either the vaporiser (true capacity can differ from the given nominal capacity – e.g. ambient temperatures of 0˚C might already lead to a 20% reduction), or the control panel (sizing of the equipment might act as a flow restrictor). The main distribution pipelines need to be assessed, including identifying the physical dimensions of length and diameter of different sections to allow for pressure calculations.


•Ward clusters – the clustering of different O2


consumers on a shared


branch pipe. The different clusters need to be identified, and the physical dimensions (length and diameter) of the branch pipelines to be identified to allow for pressure calculations. •Ward – demand levels need to be assessed, and the interdependencies of different wards in the same cluster to be considered.


n Secondly, system monitoring needs to be established. O2


data need to be gathered and aligned to ensure data integrity. In the case of reliable O2


supply data being


unavailable (e.g. if the only source for VIE flow rate data is the tank volume telemetry data), appropriate flow meters should be installed. With system monitoring implemented, it becomes possible to evaluate the hospital’s true operating capacity and pre-empt supply constraint issues.


n Thirdly, analyse the pressure loss factors to achieve higher maximum flow rates than the ‘minimal-maximum’ for the site system: •Place high O2


use/COVID-19 areas


(clusters) close to the VIE to reduce the length of the pipe section with higher flow rates, therefore minimising pressure loss. •Place high O2


use/COVID-19 wards


close to the branch root, to reduce the length of the pipe section with higher flow rates, therefore minimising pressure loss. •Balance the O2


load over multiple


ward clusters to avoid overloading a singular branch. This might conflict with the clinical desire to concentrate the COVID-19 area in a specific section of the hospital for better virus containment.


•Since a hierarchy of interdependencies exists (site-ward, clusters-ward), a definitive number for maximum achievable O2


flow is not realistic 48 Health Estate Journal January 2021


About the authors Moritz Meyer zu Köcker


Moritz Meyer zu Köcker (left) is a Logistics project manager at MAN Trucks and Bus, and a recent MPhil graduate in Industrial Systems, Manufacture, and Management, from the University of Cambridge. He also holds a B.Eng in Business Administration and Engineering from the DHBW Heidenheim, Germany, and a BA in Logistics and Supply Chain Management from the University of South Wales.


Carl-Magnus von Behr Carl-Magnus von Behr (centre) is a PhD student at the Institute for Manufacturing (IfM) at the University of Cambridge. His research looks into how inter-organisational knowledge transfer can enable resilient health service delivery in hospitals. Prior to starting his PhD, he obtained an MPhil in Industrial Systems, Manufacture, and Management from the University of Cambridge. He also holds a BSc in Industrial Engineering and Management from the Technical University Berlin, Germany.


supply and demand


without computer-aided calculations. Nonetheless, a simplified approach to estimate maximum possible flow rates can be taken to determine a ‘safe’ maximum for the worst-case scenario.


n Finally, using the data visibility from the EPR system, as well as restrictions of the O2


supply system and distribution network, a holistic patient flow and O2 consumption simulation model could be created. This model would combine the clinical information about forecasted patient numbers and the related oxygenation needs with infrastructure restrictions. With the help of simulation software, it could be predicted whether O2


flow rate restrictions on ‘site’ (i.e. VIE), ‘ward clusters’, or at ‘ward’ level, could be exceeded. These analyses could help to identify potential bottlenecks and evaluate different


policies, e.g. ward repurposing plans to create more ICU capacity.


hej


References 1 Booth R, Campbell D, 2020. High demand for oxygen risks system failure, NHS England warns. The Guardian, 7 April 2020 [https://tinyurl.com/yaezh2y2].


2 NHS, 2020. Estates and facilities alert – NHSE/I – 2020/001.


3 Department of Health, 2006a. Medical gases – Health Technical Memorandum 02-01 Medical gas pipeline systems – Part A: Design, installation, validation and verification. Stationery Office, London. Published May 2006.


4 Department of Health, 2006b. Medical gases - Health Technical Memorandum 02-01 Medical gas pipeline systems – Part B: Operational management. Stationery Office, London. Published May 2006.


Oliver Carr Lambson


Oliver Carr Lambson (right) is the co-founder of a carbon fibre electric guitar start-up, Rubato Guitars, and is particularly interested in how SMEs can contribute to African development. He recently completed his MPhil in Industrial Systems, Manufacture, and Management at the University of Cambridge. He also holds a B.Eng in Mechatronic Engineering from the University of Stellenbosch, South Africa.


Tom Ridgman Tom Ridgman worked at the IfM delivering the Industrial Systems, Manufacture, and Management MPhil course, and researching into the development


of engineering knowledge and skills in industrial settings. The earlier part of his career was spent in a range of senior management positions in the automotive industry.


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