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Prehospital pharmacological interventions
ences cited by Dr Iserson deal predominantly with documenting the safety of admixture blood warming at temperatures approaching 70 C (published several months after this manuscript was in press). However, they contain no data regarding flow rates or inflow temperatures, which are the key end points in rapid blood warming. We agree that admixture blood warming holds potential promise and await clinical trials. On the other hand, there are FDA-approved blood-warming devices that are cur-
rently commercially available for clinical use, and the apparent thermal clearance provides a useful measure of their efficiency.
Louis Flancbaum, MD Stanley Z Trooskin, MD Frederik Pedersen, PhD UMDNJ New Brunswick, New Jersey
Prehospital Pharmacological Interventions To the Editor: Although I understand the intent of the article, "Pharmacological Intervention in Prehospital Care: A Critical Appraisal" [February 1989;18:192-196[, the title disturbs me. The gist of the article is to demonstrate the statistically shaky background on which the decisions of prehospital medication selections are made, specifically cardiac medications. The article goes on to prove the point quite convincingly. However, the decision making of medication selection, particularly cardiac medications, is made primarily to maintain consistency within the guidelines of the American Heart Foundation's Advanced Cardiac Life Support Course, the "gold standard" in prehospi-' tal medicine. As such, the article has less of an impact on the prehospital care community than it should have on the authors of the ACLS text. The authors have arbitrarily committed two injustices in their article. First, if in fact their intent is to look at prehospital pharmacological interventions, they have primarily limited their view to a statistically small portion of the call volume seen by an ALS EMS service, the cardiac arrest patient. Second, it must be remembered that paramedical personnel cannot order and purchase medications without the authorization of physicians as per federal regulations. Because prehospital medicine is such a young discipline, , it seems only appropriate that in-hospital clinical trials, case control studies, and cohort studies would be used as a basis for medication selection. The authors have arbitrarily limited their focus to randomized cohort studies, unless a case control study suited their purposes (strept0kinase study). Therefore, the authors' conclusions apply equally to the hospital care community as well as the prehospital care community. The statements made by Drs Shuster and Chong regarding the relative insensitivity of the studies to detect differences are in keeping with the findings of FriemanJ The most commonly quoted reason for the insensitivity was due to small sample size. As stated previously, these particular medications make up only a percentage of the pharmacological agents used in prehospital medical care. Therefore, t h e City of Calgary EMS department would be : interested in entering into a multicenter study to examine the effect of early pharmacological interventions. As Calgary EMS is a totally ALS service with transport capabilities, it would be unethical to randomly withhold inter18:9September 1989
ventions from our service population of 650,000. Therefore, a control group from another city of similar size call volume and served by a primarily BLS or EMT-D EMS service would be ideal.
Terry Abrams, EMT-P (MSc cand) City of Calgary Emergency Medical Services Department Calgary, Alberta, Canada
1. I~riemanJA, ChalmersTC, SmithH Jr, et al: The importanceof beta, the type II error and sample size in the design and interpretation of randomized controlled trials: Survey of 71 "negative trials." N Engl J Med 1978; 299:690-694.
In Reply: Mr Abrams' reference to our arbitrary injustices and our limited view and focus suggests that he is confused about the purpose of a collective review. Many of us working with prehospital care systems believe that pharmacologic intervention in the field results in a better patient outcome than delaying treatment until the patient arrives at the emergency department. Our beliefs are based on personal observation, " c o m m o n sense," and anecdotal evidence. The aim of our critical review was to examine and summarize the published scientific evidence that supports or undermines our common beliefs. We included randomized control trials and cohort studies in our review, but excluded case reports and case series because the evidence generated by these latter study designs is unacceptably weak. We didn't set out to concentrate on drugs used in cardiac arrest; we reviewed all published articles on prehospital medications. We were as disappointed as Mr Abrams to find such a paucity of objective evaluations of pharmacologic intervention in the field. We can only conclude that our belief in the benefits of prehospital pharmacologic intervention is so far unproved.
Annals of Emergency Medicine
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rently commercially available for clinical use, and the apparent thermal clearance provides a useful measure of their efficiency.
Louis Flancbaum, MD Stanley Z Trooskin, MD Frederik Pedersen, PhD UMDNJ New Brunswick, New Jersey
Prehospital Pharmacological Interventions To the Editor: Although I understand the intent of the article, "Pharmacological Intervention in Prehospital Care: A Critical Appraisal" [February 1989;18:192-196[, the title disturbs me. The gist of the article is to demonstrate the statistically shaky background on which the decisions of prehospital medication selections are made, specifically cardiac medications. The article goes on to prove the point quite convincingly. However, the decision making of medication selection, particularly cardiac medications, is made primarily to maintain consistency within the guidelines of the American Heart Foundation's Advanced Cardiac Life Support Course, the "gold standard" in prehospi-' tal medicine. As such, the article has less of an impact on the prehospital care community than it should have on the authors of the ACLS text. The authors have arbitrarily committed two injustices in their article. First, if in fact their intent is to look at prehospital pharmacological interventions, they have primarily limited their view to a statistically small portion of the call volume seen by an ALS EMS service, the cardiac arrest patient. Second, it must be remembered that paramedical personnel cannot order and purchase medications without the authorization of physicians as per federal regulations. Because prehospital medicine is such a young discipline, , it seems only appropriate that in-hospital clinical trials, case control studies, and cohort studies would be used as a basis for medication selection. The authors have arbitrarily limited their focus to randomized cohort studies, unless a case control study suited their purposes (strept0kinase study). Therefore, the authors' conclusions apply equally to the hospital care community as well as the prehospital care community. The statements made by Drs Shuster and Chong regarding the relative insensitivity of the studies to detect differences are in keeping with the findings of FriemanJ The most commonly quoted reason for the insensitivity was due to small sample size. As stated previously, these particular medications make up only a percentage of the pharmacological agents used in prehospital medical care. Therefore, t h e City of Calgary EMS department would be : interested in entering into a multicenter study to examine the effect of early pharmacological interventions. As Calgary EMS is a totally ALS service with transport capabilities, it would be unethical to randomly withhold inter18:9September 1989
ventions from our service population of 650,000. Therefore, a control group from another city of similar size call volume and served by a primarily BLS or EMT-D EMS service would be ideal.
Terry Abrams, EMT-P (MSc cand) City of Calgary Emergency Medical Services Department Calgary, Alberta, Canada
1. I~riemanJA, ChalmersTC, SmithH Jr, et al: The importanceof beta, the type II error and sample size in the design and interpretation of randomized controlled trials: Survey of 71 "negative trials." N Engl J Med 1978; 299:690-694.
In Reply: Mr Abrams' reference to our arbitrary injustices and our limited view and focus suggests that he is confused about the purpose of a collective review. Many of us working with prehospital care systems believe that pharmacologic intervention in the field results in a better patient outcome than delaying treatment until the patient arrives at the emergency department. Our beliefs are based on personal observation, " c o m m o n sense," and anecdotal evidence. The aim of our critical review was to examine and summarize the published scientific evidence that supports or undermines our common beliefs. We included randomized control trials and cohort studies in our review, but excluded case reports and case series because the evidence generated by these latter study designs is unacceptably weak. We didn't set out to concentrate on drugs used in cardiac arrest; we reviewed all published articles on prehospital medications. We were as disappointed as Mr Abrams to find such a paucity of objective evaluations of pharmacologic intervention in the field. We can only conclude that our belief in the benefits of prehospital pharmacologic intervention is so far unproved.
Annals of Emergency Medicine
1025/185