Effects of setting up of humidifiers on thermal conditions and subjective responses of patients and staff in a hospital during winter.

The purpose of this survey was to measure the thermal environment in a hospital during winter, and to investigate the subjective responses of patients and staff via a questionnaire. The air temperature and humidity in the sickrooms and nurse stations were measured for 3 months during winter. After 2 months, we introduced humidifiers into about half of the rooms and nurse stations as a method of improving the environment, and evaluated the effects of the installed humidifiers on the thermal conditions. In all, 36 patients and 45 staff members were asked once a week about subjective symptoms (dry and itchy skin, thirst, etc.). Before setting up the humidifiers, the existence of a low-humidity environment in the hospital during winter was confirmed, with the levels of relative humidity and humidity ratio reaching under 50% and 5g/kg DA, respectively, which is known to promote the spread of influenza viruses. However, the introduction of the humidifiers increased the relative humidity in sickrooms from 32.8% to 43.9% on average, and the air humidity in sickrooms thus almost reached the optimum range suggested by the Hospital Engineering Association of Japan (HEAJ). Additionally, complaints of thermal discomfort and dryness of air decreased among the staff, though not among the patients, after the humidifiers were installed. These results suggest that introducing humidifiers into a hospital during winter is an effective method of improving the low-humidity environment and relieving the discomfort of staff members.

Thermal environment and subjective responses of patients and staff in a hospital during winter.

The purpose of this study was to ascertain the actual conditions of the thermal environment and the symptoms of patient and staff (nurses and nurses' aides) during winter in a hospital. We measured the ambient temperature and humidity in sickrooms, nurse stations, and corridors. The subjects included 36 patients and 45 staff members. The existence of low humidity environments (relative humidity was less than 40%) in a hospital during winter was confirmed, and the levels of low humidity reached those known to promote the spread of influenza viruses. Thermal comfort of patients was not directly connected to the low humidity in sickrooms. However, 54.9% and 73.4% of patients were conscious of itchy skin and thirst, respectively. The majority of the staff members were working with itchy skin and thirst. These results suggested that extreme low humidity in a hospital during winter presents problem that should be solved quickly.