Associations of systemic oxygen consumption with age and body temperature under general anesthesia: retrospective cohort study

BACKGROUND: Body temperature (BT) is thought to have associations with oxygen consumption (VO(2)). However, there have been few studies in which the association between systemic VO(2) and BT in humans was investigated in a wide range of BTs. The aims of this study were 1) to determine the association between VO(2) and age and 2) to determine the association between VO(2) and BT. METHODS: This study was a retrospective study of patients who underwent surgery under general anesthesia at a tertiary teaching hospital. VO(2) was measured by the Dräger Perseus A500 anesthesia workstation (Dräger Medical, Lubeck, Germany). The associations of VO(2) with age and BT were examined using spline regression and multivariable regression analysis with a random effect. RESULTS: A total of 7,567 cases were included in this study. A linear spline with one knot shows that VO(2) was reduced by 2.1 ml/kg/min with one year of age (p < 0.001) among patients less than 18 years of age and that there was no significant change in VO(2) among patients 18 years of age or older (estimate: 0.014 ml/kg/min, p = 0.08). VO(2) in all bands of BT < 36.0 °C was not significantly different from VO(2) in BT > = 36 °C and < 36.5 °C. Multivariable linear regression analysis showed that compared with VO(2) in BT > = 36 °C and < 36.5 °C as a reference, VO(2) levels were significantly higher by 0.57 ml/kg/min in BT > = 36.5 °C and < 37 °C (p < 0.001), by 1.8 ml/kg/min in BT > = 37 °C and < 37.5 °C (p < 0.001), by 3.6 ml/kg/min in BT > = 37.5 °C and < 38 °C (p < 0.001), by 4.9 ml/kg/min in BT > = 38 °C and < 38.5 °C (p < 0.001), and by 5.7 ml/kg/min in BT > = 38.5 °C (p < 0.001). The associations between VO(2) and BT were significantly different among categorized age groups (p = 0.03). CONCLUSIONS: VO(2) increases in parallel with increase in body temperature in a hyperthermic state but remains constant in a hypothermic state. Neonates and infants, who have high VO(2), may have a large systemic organ response in VO(2) to change in BT. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12871-023-02182-1.