Interpretation of Body Temperature and Oxygen Saturation based on Individual Normal Ranges in Habitual Condition: A Step Forward for Applied Precision Medicine

Abstract

Background: Precision medicine aims to provide patients with care and treatment based on the individual's unique conditions. Current reference ranges for vital parameters are based on healthy reference populations at group level, usually male, individuals excluding long-term medical conditions and daily medication. This entails a risk of misinterpretation on each measurement occasion because a deviant value for the individual may be camouflaged by a normal value at group level. We believe that precision medicine in practice requires that values for vital parameters are interpreted in relation to the individual's normal range in habitual condition. Aim: To investigate body temperature and oxygen saturation in healthy and frail individuals, based on individual normal range in habitual condition. Methods: The sample consisted of 70 healthy individuals, 27 to 80y, 20 nursing home residents, 70 to 100y, and 32 patients in hospital-affiliated home care, 60 to 95y. Age, gender, physical ability, chronic disease, medication was documented. Ear temperature and oxygen saturation were performed for five mornings before getting out of bed and taking medicine, food or drink. Results: The range for body temperature in healthy subjects was 34.3°C to 37.7 °C and in frail elderly 34.5°C to 37.7 °C. No differences in the variation of normal range in body temperature was found between healthy and frail individuals, 0.7°C + 0.4°C, though the variation between min and max temperature were large; 2.4°C vs 2.7°C and 2.9°C vs 2.3°C in healthy and frail subjects, respectively. A max temperature of < 36.2°C was more frequent in healthy subjects. The range for oxygen saturation varied between 85% to 99%, in healthy subjects and 75% to 100% in frail elderly. No healthy subjects had a max oxygen saturation value <94%. Inflammatory processes influenced body temperature and oxygen saturation in frail elderly. Conclusion: To promote precision medicine and health our results show that it is necessary to interpret body temperature and oxygen saturation based on individual normal ranges in habitual condition. By interpreting deviations from the individual's normal interval, the possibility of necessary care efforts increases without delay, which can be decisive before further deterioration.