Background and importance The introduction of 93% oxygen (±3%) in the EU Pharmacopoeia has allowed its therapeutic use. Production costs are related to electricity and maintenance. Each oxygen cubic meter (m³) produced consumes 0.75 kWh, approximately €0.21/m³, while gaseous oxygen in cylinders for system backup costs about €0.50/m³. The production plant works at low pressures (8 vs 200 bar) and is compact.

Aim and objectives The objective was to estimate 93% oxygen consumption in 2018 in a hospital equipped with this system to compare the cost versus the purchase 99% oxygen.

Material and methods Data were acquired from the plant located in a small hospital (33 places): percentage purity, energy consumption, possible interruption of operation and quantity produced. Data were subsequently processed by Microsoft Excel software.

Results In 2018, 12 095 m³ of 93% oxygen were produced for an electricity charge of €2539.95. During the year before the installation (2014), 18 000 m³ of oxygen 93% were consumed for a cost of around €55 000. The cost reduction was over 50%. Oxygen content always remained within the range (average 94.88%, maximum 95.89%, minimum 93.22%). The randomised controlled trial (RCT) that took place in the first year of use to demonstrate the overlapping efficacy of the two alternatives gave the following results:

• 93% oxygen group: 95% l/min flow, 91% sat O₂, in range, 92% EGA T1 in range;

• Oxygen group 99%: 97% l/min flow, 90% sat O₂, in range, 93% EGA T1 in range.

Conclusion and relevance This analysis highlights the goodness of the investment and the reliability of the system. The annual consumption of oxygen was reduced due to less waste compared with the use of 99% oxygen cylinders. Significant savings have been made for the hospital, maintaining the quality, safety and efficacy of the drug, as demonstrated by the RCT performed.

References and/or acknowledgements No conflict of interest.