Abstract

Abstract: Increasing emphasis on managing acute alcohol- and drug-induced medical-psychiatric conditions demands that rapid screening diagnostic procedures be available to the physician. Since it obviously is useful to have some idea of the blood alcohol concentration (BAC), the feasibility of using plasma osmolality as a reflection of BAC is discussed. The increment in plasma osmolality caused by a unit increase in plasma alcohol is linear, eg, a rise in plasma osmolality of 21.7 mOsm/kg H2O reflects a 100 mg/100 ml increase in plasma alcohol. Since plasma osmolality can be determined rapidly and easily, it can yield useful information and often preface a more thorough biochemical examination. Furthermore, concomitant measurement of urine osmolality can be an indicator of the state of hydration in the acute alcoholic condition. Obtaining an estimate of BAC (by measuring plasma osmolality) allows the physician to correlate signs and symptoms with BAC and to more skillfully plan the psychopharmacologic approach to the patient.