Extracorporeal therapy in the treatment of intoxication.

Abstract

THE GREEKS did it with hemlock, as immortalized by Socrates. The ancient physician, Galen, devoted himself to the perfection of Theriac, the universal antidote, composed of more than seventy ingredients, including viper's flesh. Poisoning is as old as the human condition; only patterns of drug use and treatment of poisoning have changed with time. While twenty years ago aspirin and barbiturates were leading causes of serious intoxication, today antidepressants, tranquilizers, and acetaminophen have taken the lead. Narcotics are an age-old source of drug intoxication and remain a major problem today. The majority of drug poisoning documentations are made through emergency room (ER) visits. The statistics available for 1981 from the Drug Abuse Warning Network (DAWN) of the National Institute on Drug Abuse l reveal that 1 out of every 166 ER visits was due to drug intoxication. Table 1 lists the ten drugs (or drug groups) most frequently mentioned by ERs in the DAWN survey. The statistics for each drug include the frequency with which it was mentioned by ERs, expressed as a percentage of total ER visits; admissions to the hospital as a percentage of ER mentions of the drug; and medical examiner mentions of the drug as a percentage of total deaths. Of note is the frequency with which drugs were taken in combination with ethanol or other drugs-46 % of ER visits and 63 % of deaths involved multiple drugs. For the benzodiazepines, in particular, over 70% of the ER mentions included another drug (ethanol half the time) and over 90 % of medical examiners mentions included at least one other drug. In fact, death rarely occurs from the ingestion (versus intravenous use) of benzodiazepines alone. Approximately 40% of drug-related cases required admission to the hospital, but less than 2.3% resulted in death (if narcotics and patients dead-on-arrival are excluded, the figure is 1.1 %). These impressive statistics on survival are relatively new. The mortality rate from drug overdose was over 20% as recently as 25 to 30 years ago, when CNS stimulation was the crux of therapy. Drugs such as pentylenetetrazol, picrotoxin, and amphetamines were considered essential and were not readily abandoned. 2.3 Even with reported increased incidences of seizures, cardiac arrhythmias, and vomiting, it took many years to recognize that mortality statistics were, in fact, worse with this aggressive intervention. 4.5 The first major step toward improvement of outcome resulted from lessons learned in the treatment of shock on the battlefields of World War II and applied by Kirkegaard6 to show the importance of circulatory collapse in intoxication. In addition, in 1951, Nilsson7 established the importance of a clear and patent airway and prevention of hypoxia. The final leap in patient care came in 1961 when Clemmesen and Nilsson8 demonstrated systematically from 12 years experience in Copenhagen averaging more than 1,500 cases of poisoning per year, that intensive supportive therapy, without massive gastric lavage or analeptic agents, resulted in mortality rates of 1.5 %. Acceptance of their Scandinavian Method, as it came to be known, and abandonment of analeptic therapy has led to the excellent mortality statistics seen today. It is toward the small group of patients who fail to respond to intensive supportive care that treatment innovations, especially extracorporeal therapy, have been directed. The rationale for extracorporeal treatment is straightforward: since poisons achieve their toxic effect on target organs via the blood stream, their elimination from the blood should result in amelioration of the patient's condition. Forced diuresis was used to accelerate elimination, but with the advent of technology for hemodialysis, direct access to and removal of poisons from the circulation became a possibility. The development of hemoperfusion permitted even more effective removal of substances from the blood. Although the pur-