Operating theatre room temperatures and relative humidity levels at a central hospital

Phukubye, Phyllis Mabotse
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Background The aim of this study was firstly to assess the accuracy of the current OT room thermometers against a “gold standard”, as well as to evaluate OT rooms’ temperature and relative humidity (RH) at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) during summer and winter. Methods Temperature and RH were assessed using a calibrated sling hygrometer and the OT room wall thermometer. Bland and Altman plots were used to analyse the strength of the relationship between the two instruments. The attending anaesthetists were asked their opinion of the appropriateness of the OT room temperature and this was related to the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) guidelines. Results There were strong correlations (r ≥0.7) between the OT wall temperatures and the sling hygrometer in both summer and winter. There were weak correlations (r < 0.4) between the ambient temperature and OT room thermometers. Good agreement between the OT room thermometer and the sling hygrometer was found for temperature only. RH in the cardiac OT (78%) was higher than recommended by the ASHRAE guidelines. There was no correlation between seasonal variation in the summer and winter months in the OT rooms, as well as no correlation between the anaesthetist’s opinion of the appropriateness of the OT room temperature and the temperature on the thermometer. Conclusion The current OT room wall thermometers at CMJAH are accurate for temperature but not for RH; therefore, subjective reliance on temperature is unnecessary. OT room thermal guidelines need to be formulated, as the current ASHRAE guidelines do not accommodate different patient’s thermoregulatory requirements. It is possible that at CMJAH, some surgeries are occurring in inappropriate thermoregulatory conditions, which could affect patient and OT room safety.
A research report submitted in partial fulfilment of the requirements for the degree of Master of Medicine in the branch of Anaesthesiology, to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2020