ABSTRACTS

practice and health beliefs may actually contribute to anx- iety are discussed.

Andrew Brick, MD

electric shock, venom, crotalid

Electr ic shocks are ineffect ive t rea tment of lethal e f fects of ra t t lesnake envenomation in mice Johnson EK, Kardong KV, Mackessy SP Toxicon 25:1347-1349 Dec 1987

study recommends that wounds in the subcutaneous and muscle layers that cause no bleeding in the retroperitoneal space can be managed on an outpatient basis. With evidence of retroperitoneal hemorrhage but no visceral damage (fat planes undisturbed), observation for three days is adequate. Evidence of visceral damage requires specific individual sur- gical intervention, and intraperitoneal penetration requires laparotomy. In conclusion, triple-contrast CT of the retro- peritoneum and viscera is excellent, allowing triage and re- ducing the number of unnecessary hospital izations and laparotornies.

Duncan Sauer, MD

The use of high-voltage, low-amperage electric shock to treat human snake bite victims has been proposed. The au- thors simulated the conditions of an original report, shock- ing mice that were intramuscularly injected with Crotalus viridds oreganus (northern Pacific rattlesnake) with an auto- motive ignition coil run by a 12-V battery delivering 20 to 25 kV, < 1 mA. The venom was pooled and reconstituted by standard measures. Venom doses included a range of 0.75 to 6 mg/kg, which included the LDso dose. Experimental mice received venom and ten separate shocks of less than one second duration, all within 60 seconds of envenomation. Twenty-four hour survival was followed. None of the shocked experimental mice in any dosage survived at a greater frequency than the control group of that dosage. The authors conclude that high-voltage, low-amperage electric shock is not efficacious in treating the lethal effects of rat- tlesnake envenomation in mice./Editor 's note: Combined with numerous commentaries in the literature, this report currently makes it impossible to recommend this contro- versial treatment in human rattlesnake envenomations.]

Richard C Dart, MD

CT scan, injury, abdominal

Triple-contrast computed tomography in the evaluation of penetrat ing abdominal injuries Hauser C J, Huprich JE, Bosco P, et al Arch Surg 122:1112-1115 Oct 1987

The combination of a low frequency of significant injury and the late presentation of these injuries led to a study of posterior penetrating trauma evaluating the efficacy of com- puted tomography {CT) imaging. Forty patients with stab wounds or low-energy gunshot wounds that had passed solely through truncal soft tissues located posterior to the midaxillary line were studied. Hemodynamic instability, peritonitis, hematemesis, or massive hematuria excluded patients from the study. Triple-contrast CT scanning with gastrografin was used to evaluate 35 stab wounds and five gunshot wounds. Penetrating injuries are recognizable by air, and it appears that this method images the retroperito- neal structures well enough to allow triage policy. The

tissue plasm!nogen activator, myocardial infarction, coronary angioplasty

A randomized trial of intravenous t issue plasminogen act ivator for acute myocardial infarction with subsequent randomizat ion to e lect ive coronary angioplasty Guerci AD, Gerstenblith G, Brinker JA, et al N Engl J Med 317:1613-1618 Dec 1987

This double-blind randomized s tudy compared plas- minogen activator (tPA, 80 to 100 rag) with placebo in 138 patients presenting within four hours of the onset of myo- cardial infarction. During tPA infusion, patients underwent thallium scanning and technetium blood-pool imaging fol- lowed by coronary arteriography one to six hours after tPA infusion. Patients were eligible for angioplasty if there was unequivocal identification of the infarct-related artery with a discrete stenosis greater than or equal to 70%. Candidates for angioplasty were randomly assigned either to undergo angioplasty on the third hospital day (n = 42} or not to undergo angioplasty (n = 43). On the tenth hospital day, patients again underwent gated blood-pool imaging at rest, and if able, during submax ima l exercise on a bicycle ergometer. The patency rates of the infarct-relatedarteries were 66% in the tPA group and 24% in the placebo group. tPA administration was associated with a significant im- provement in the ejection fraction at rest on the tenth hos- pital day, and a significant reduction in the prevalence of congestive heart failure. There were no differences in mor- tality. The effect of tPA was observed in-inferior as well as anterior infarcts. Angioplasty had an 84% success rate in reducing the stenosis by 30% or more. Angioptasty had no significant effect on the ejection fraction or the incidence of congestive heart failure. However, elective angioplasty, per- formed a mean period of three days after admission, reduced the incidence of subsequent ischemic events and improved left ventricular function during submaximal exercise. There were no fatal complications using tPA in this study. These results support early administration of tPA in community hospitals without delay or the need for emergency transport with deferred catheterization and angioplasty. However, this study did not compare immediate catheterization with an- gioplasty to deferred angioplasty after tPA infusion.

Mark Murphy, MD

160/658 Annals of Emergency Medicine 17:6 June 1988