[Early effects of exposure to anesthetic gases and vapors. A critical review on the suitability of several indicators of the effect].
Apart from a risk excess of liver disease among operating theatre personnel and of spontaneous abortion in women exposed during pregnancy, no definitive conclusion can be drawn regarding health impairment among anaesthesiology staff. However, many studies pointed out that several adverse effects occur as a consequence of experimental, therapeutic and occupational exposure to inhalation anaesthetics. This paper reviews the early changes of the organ systems (hepatobiliary, renal, cardiac, hematopoietic, reproductive systems; immunologic functions; cytogenetic effects), which are considered to follow anaesthetics exposure, to evaluate their possible use as biological indices of effect. The liver microsomal enzyme system has received particular attention with the aim of clarifying the mechanisms involved in anaesthetics hepatotoxicity. An increased microsomal enzyme activity was observed in experimental conditions and in humans. This inductive effect, which reflects metabolic changes affecting liver function, is commonly considered the earliest sign caused by exposure to several chemicals (other than anaesthetics) and may be evaluated by means of biomarkers, among which the measurement of urinary D-glucaric acid excretion is a well established non-invasive tool. Urinary D-glucaric acid excretion represents the most promising early metabolic effect of the exposure to anaesthetics. However, its measurement is not yet suitable as an index of effect for use in biomonitoring practice. The main aspects to be studied in the future are the following: (i) the evaluation of urinary D-glucaric acid excretion in the acute and chronic exposure to low-dose anaesthetics to check the existence of a dose-response relationship; (ii) the study of other parameters (urinary enzymes, immunological profile, chromosome aberrations) in selected groups of exposed and control subjects, in which both exposure and confounding factors (age, gender, life style, former diseases) as well as concomitant occupational exposures should be carefully taken into account.