Oxidation-reduction (redox) potentiometry in blood in geriatric conditions: a pilot study

Oxidation-reduction (redox) potentials in blood were measured potentiometrically in 36 elderly people: 26 long-stay patients in a nursing home and 10 healthy elderly people (controls). The geriatric patients were obviously more affected by various chronic geriatric conditions, clearly used more medications, and had much higher quantitative invalidity scores (help index) compared to the control group. The average redox potential (Eh) in the geriatric patients was significantly (p less than 0.001) higher (300 mV +/- 24) than that in the control group (269 mV +/- 19). Repeated measurements showed some intraindividual variability of Eh. The pH in blood and a number of haematological and anthropometrical parameters did not differ significantly, except for the haemoglobin content, which was somewhat lower in the geriatric group (p less than 0.02). Eh did not correlate with the haemoglobin content. In addition, no effects of age or sex on the value of Eh were found. It was concluded that the general physical condition of the geriatric patients could be responsible for an increase of Eh, although drug effects and nutritional factors could not be excluded. Eh can be regarded as a measure for the balance of oxidant and reductant component in tissue fluids. Comparison between the Eh of younger and healthy elderly people indicates that this balance is apparently unaltered in healthy elderly persons, although elderly people may be more susceptible to disturbance by disease conditions, possibly as a result of a decreased homeostatic capacity of the redox balance. As many redox components play a role in the biochemistry of oxy-radicals, one may speculate on the possible value of Eh in relation to oxy-radical tissue damage.