Background: In clinical practice, oxygen saturation as measured by photoplethysmography and arterial oxygen tension as determined by blood gas analysis are the parameters used frequently to estimate the oxygen status of a patient. Additionally, the cardiac output CO and the arterial oxygen content CaO2 are critical for the delivery of oxygen ḊO2 to organs and tissues. So far, CaO2 reference values published by Mertzlufft and Zander (1984) and Siggaard-Andersen (1990) are widely used. The aim of the present study was to reevaluate previously published results using the results of a population-based study. Furthermore, the impact of smoking on CaO2 will be assessed.
Patients and methods: Data of 1018 volunteers from the Study of Health in Pomerania (SHIP) were analyzed. CaO2 was calculated from blood gas analysis of capillary blood obtained from a hyperemised ear lobe. Reference value equations controlled for sex, age and smoking were derived with quantile regression analysis and fractional polynomials.
Results: Lower limits of normal (LLN) decline with age. Current smoking has no significant influence on LLN for CaO2.
Conclusion: Sex, age and smoking-specific normal values can be calculated using the current equations.
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