The Journal

of Emergency

Medicine,

Vol 10, pp 491-499,

Printed in the USA . Copyright

1992

Press Ltd.

for 15 minutes (to simulate prehospital resuscitation), after which the catheter was removed and a second whole blood specimen for BAL was obtained. Specimens were refrigerated prior to undergoing standard analysis via gas chromatography.

0 To the Editor: We read with interest the article on blood ethanol clearance rates by Gershman and Steeper in the September/October 1991 JEM (1). We have been studying related topics regarding ethanol metabolism, clearance, and decontamination (2) and were concerned by the lack of information provided by the authors about the administration of intravenous (IV) fluids to their patients. Their study included emergency department (ED) patients with diagnoses such as multiple trauma and gastrointestinal hemorrhage, that likely were associated with hypovolemia and required IV resuscitative fluids. Since it is generally accepted that the volume of distribution for ingested ethanol is the patient’s plasma volume (PV) (3), it might be expected that expansion (by IV fluid administration) or contraction (by hemorrhage, diuresis, etc) of the PV would directly affect both overall clearance of ethanol and accuracy and reproducibility of individual blood alcohol level (BAL) measurements. Iatrogenic manipulation of the BAL in the ED has both medical and legal ramifications. We are specifically interested in the potential effects of prehospital hemorrhage and fluid resuscitation on BALs. Pursuant to this interest, we recently conducted a pilot study on healthy volunteers.

RESULTS All patients completed the study. Initial and posthydration BALs, along with infusion volumes, are tabulated in Table 1. Although there was variation among BALs and relative changes in BAL, we could identify .no significant differences or predictable trends. DISCUSSION There is a paucity of data in the literature regarding the effects of fluid resuscitation on serial measurements of BAL (4,5). After an individual ingests ethanol (EtOH), multiple factors are thought to affect absorption, distribution, and elimination, all of which play interacting roles in determining the measured serum alcohol concentration at any given time. For example, the rate of EtOH consumption, the amount of ingested EtOH remaining unabsorbed in the stomach, the patient’s weight and hydration status pre-ingestion, the degree of individual tolerance, and the presence of coingestants all contribute to the minute-to-minute changes in BALs. More important elimination considerations include the degree of enzyme induction and whether or not zero- or firstdegree kinetics are followed in the individual patient. Plasma volume size is often manipulated by the addition of IV fluids or by inducing diuresis. While this solute-solvent effect on the concentration of any constituent within it may be straightforward, the specific effect on EtOH is difficult to interpret because of the simultaneously occurring processes of absorption, distribution, metabolism, and elimination. The

METHODS Nineteen healthy volunteers (age 21 to 42 years, mean f SD 23.5 f 2.9; 14 males and 5 females) fasted for at least 6 hours and then consumed beer until clinical evidence of inebriation was established, substantiated by breathalyzed (Alto-Sensor@ , Intoximeters, Inc., St. Louis, MO) ethanol levels above 90 mg/dL. As a large-bore (16- or 1%gauge) IV line was initiated, a whole blood specimen was obtained from a peripheral vein for subsequent BAL analysis. Normal saline was then infused IV at a wide-open rate = =

0 1992 Pergamon

Guidelines for Letters-Letters will appear at the discretion of the editor as space permits and may be subjected to some editing. Three typewritten, double-spaced copies should be submitted.

0736~4679/92 $5.00 + .OO 491

492

The Journal

of Emergency

Medicine

Table 1. Data from 19 Healthy Euvolemic Volunteers Reflecting Change in BAL after Cessation of Alcohol Intake and Infusion of a Bolus of Normal Saline (BAL = blood alcohol level) Prehydration Range Mean f SD

BAL, mg/dL

80-205 137.9 f 11.1

effect of the size of the PV on hematocrit, electrolytes, blood viscosity, platelet aggregation, and other typical blood assays has been considered by various authors (6,7). Ethanol has not been similarly studied, despite a long-standing interest in back-extrapolating initial EtOH levels from measurements taken upon ED presentation or legal apprehension (8). Since many ED patients who present in an inebriated state have synchronous illnesses or injuries that require fluid resuscitation, this potential effect is of interest from both medical and legal perspectives. The data from this pilot study (Table 1) do not indicate that there is any predictable effect of bolus hydration on BALs in healthy, fasting, euvolemic volunteers. We are currently conducting a study of the effects of prehospital hydration on the BALs of inebriated patients. The potential effects of continued hydration of inebriated patients may require further study. Vincent J. Toups, MD Charles V. Pollack, Jr., MA, MD Frederick B. Carlton, MD, FACEP Division of Emergency Medicine University of Mississippi Medical Center Jackson, Mississippi

REFERENCES 1. Gershman H, Steeper J. Rate of clearance of ethanol from the blood of intoxicated patients in the emergency department. J Emerg Med. 1991;9:307-11. 2. Pollack CV, Jorden RC, Carlton FB, Baker ML. Gastric emptying in the acutely inebriated patient. J Emerg Med. 1992;lO: 1-5. 3. Rall TW. Hypnotics and sedatives; ethanol. In: Goodman LS, Gilman AZ, Gihnan AG, eds. Goodman and Gilman’s Pharmacologic Basis of Therapeutics. 8th ed. New York: Pergamon; 1990~345-82. 4. Bogusz M, Path J, Stasko W. Comparative studies on the rate of ethanol elimination in acute poisoning and in controlled conditions. J Forens Sci. 1977;22:446-51. 5. Beck W von. Blutalkohol nach Blutverlust und Blutersatz. Muench Med Wochschr. 1%1;103:200-3. 6. Greenfield RH, Bessen HA, Henneman P. Effect of crystalloid infusion on hematocrit and intravascular volume in healthy, nonbleeding subjects. Ann Emerg Med. 1989;18:51-5. 7. Galea G, Davidson RJL. Some haemorheological and haematological effects of alcohol. Stand J Haematol. 1983;30:308-10.

Volume infused, mL

Posthydration BAL, mg/dL

400-l 500 888 f 43

77-213 132.0 f 11.1

8. Bayly RC, McCallum NEW. Some aspects of alcohol in body fluids; part 2: the change in blood alcohol concentration following alcohol consumption. Med J Austral. 1959;2:173-6.

Cl To the Editor: Thank you for the opportunity to reply to the letter of Drs. Toups, Pollack, and Carlton concerning hydration and clearance of serum ethanol. This is an issue often raised by ED personnel and based on the common “wisdom” that rehydration or forced diuresis ought to increase the clearance of ethanol from the body. We considered this as a possible variable in designing our study, but unlike Toups et al., we concluded that there was no theoretical basis for this notion. Toups et al. cite Rall in Goodman and Gilman (1) when they state that “the volume of distribution for ingested ethanol is the patient’s plasma volume.” In fact, that article states “After absorption, ethanol is fairly uniformly distributed throughout all tissues and all fluids of the body” (reference 1, p. 375, paragraph 5). Volume of distribution is defined as “the fluid volume that would be required to contain all the drug in the body at the same concentration as in blood or plasma” (2). Therefore, a drug such as ethanol that is evenly distributed throughout all body tissues and fluids would have a volume distribution approaching 1 .O. Toups, Pollack, and Carlton, in contrast, appear to be assuming that all the absorbed ethanol is contained in the plasma compartment. If this were true, volume repletion, or for that matter forced diuresis, would indeed change both blood ethanol levels and clearance. In reality, for a 70-kg man, the blood volume is approximately 5.5 liters, while the total body water is approximately 42 liters (2). A patient with a significant dehydration, for example, a free water deficit of 2 liters, would have a total body water content of 40 liters, or 95.2% of normal. A blood alcohol level of 200 mg/dL would be decreased to 190 mg/dL if this patient were then fully rehydrated. Less profound dehydration would result in even less of a change. The rate of clearance would be un-

Blood ethanol clearance rates.

The Journal of Emergency Medicine, Vol 10, pp 491-499, Printed in the USA . Copyright 1992 Press Ltd. for 15 minutes (to simulate prehospital r...
221KB Sizes 0 Downloads 0 Views