<b>A Preliminary Point-of-Care Tool for Estimating Medical Oxygen Demand: Cornerstone for Fighting COVID-19 and Future Respiratory Epidemics</b>
<p dir="ltr"><b>ABSTRACT</b></p><p dir="ltr"> <b>Background:</b> The COVID pandemic has put immense stress on the health infrastructure. COVID-19 disease causes viral pneumonia with cytokine storm; up to 20% of symptomatic infection/vaccine-naive patients require supplemental oxygen and hospitalization (SpO2 <92%). The sources of oxygen in a hospital are liquid medical oxygen, cylinders, concentrators, and pressure swing adsorption plants. Oxygen cylinders are the foremost source in resource-limited settings. During the second wave of infections (Delta Variant) in India, the daily liquid medical oxygen (LMO) requirement increased from 3095 MT to more than 9000 MT. This problem was solved by roping in industrial oxygen. In times of scarcity, accurately calculating oxygen demand is crucial to ensure equitable distribution. This remains a significant hurdle, as the calculations involved can be complex, particularly in peripheral areas where trained personnel may be limited. Medical oxygen therapy is life-saving and cannot be delayed. </p><p dir="ltr"><b>Methods:</b> To address these logistical challenges, a point-of-care tool prototype was developed to facilitate the easy calculation of a hospital's liquid medical oxygen requirements, as well as to estimate the time remaining before a cylinder or manifold runs out of oxygen. Clinical application of the Ideal gas law was used to derive formulae for oxygen consumed based on patient flow rate, and thereafter, a spreadsheet-based tool was developed* using MS-Excel. Calculations performed manually and using the tool (for 2 hypothetical scenarios) were compared for equivalence using a two-sample independent t-test. </p><p dir="ltr"><b>Results:</b> A spreadsheet-based digital tool was developed for calculating medical oxygen need. There was no significant difference between manually calculated and spreadsheet calculated oxygen demand figures, t(2)=0.00044, p=0.99. These findings demonstrate that the framework developed is suitable for use, pending further validation. </p><p dir="ltr"><b>Conclusion:</b> A preliminary digital tool (provided as a spreadsheet/app) for the calculation of medical oxygen demand was developed. It can be further developed and validated for usage by procurement agencies to quickly estimate daily oxygen requirements based on the number of patients admitted, boosting preparedness to combat mutant SARS-CoV-2 variants and/or other pandemic viruses. The tool can also be used under nominal conditions in resource-limited settings.</p><p dir="ltr"> *The preliminary tool developed is provided as a spreadsheet in the supplementary material.</p>
