Adrenaline in Cardiac Arrest - Coursework Example

Adrenaline," in the synthetic form called epinephrine, "has been used for heart problems for about 100 years" (EMS, 2004). Its effect is to constrict blood vessels and boost blood pressure, thereby restarting the circulation. Adrenaline is often administered as a secondary measure, "when shocking the heart with a defibrillator fails to revive the patient" {AP, 2004). However, physicians conducting a two-year study at the Royal Infirmary of Edinburgh (BMJ, 1995) found that paramedics specially trained and allowed to administer various drugs to cardiac patients outside of hospital had no substantially greater success or improved survival rates over medical technicians supplied with basic CPR skills and semi-automatic defibrillators (paraphrased from graphs. 1-3). In a related study (Heart, 1997), researchers found results consistent with a continued skepticism over the use of adrenaline. According to this article, "Some emergency medical staff were authorised to give standard doses of adrenaline during the observational period. Adrenaline was given to 35% of patients and was associated with a significantly greater rate of restoration of spontaneous circulation and hospital admission. However, there was no significant difference in hospital discharge rates between the two groups. Thus adrenaline and its dosage during cardiac arrest remain controversial" (412-414). It appears that when paramedics and other qualified emergency medical personnel give adrenaline to cardiac arrest patients in the field, it significantly improves the chance that the patient will live long enough to be admitted to the hospital, but it does not significantly improve the chance that patient will survive long enough to be discharged from the hospital. Adrenaline is good for buying the patient an extra few hours or an extra day filled with tests and possibly some invasive treatments. It may not be good for much more. It should be pointed out that these findings may be more germane to patients who are found in ventricular fibrillation, rather than asystole. According to a study carried out in Sweden and reported in Resuscitation (1995a) Jun;29(3):195-201., "A large proportion of cardiac arrests outside hospital are caused by ventricular fibrillation. Although it is frequently used, the exact role of treatment with adrenaline in these patients remains to be determined. AIM: "To describe the proportion of patients with witnessed out-of-hospital cardiac arrest found in ventricular fibrillation who survived and were discharged from hospital in relation to whether they were treated with adrenaline prior to hospital admission. PATIENTS AND TREATMENT: "All the patients with out-of-hospital cardiac arrest found in ventricular fibrillation in Goteborg between 1981 and 1992 in whom cardiopulmonary resuscitation (CPR) was initiated by our emergency medical service (EMS). During the observation period, some of the EMS staff were authorized to give medication and some were not. RESULTS: "In all, 1360 patients were found in ventricular fibrillation and detailed information was available in 1203 cases (88%). Adrenaline was given in 417 cases (35%). Among patients with sustained ventricular fibrillation, those who received adrenaline experienced the return of spontaneous circulation more frequently (P < 0.001) and were hospitalized alive more frequently (P < 0.01). However, the rate of discharge from hospital did not differ significantly between the 2 groups. Among patients who converted to asystole or electromechanical dissociation, those who received adrenaline experienced the return of spontaneous circulation more frequently (P < 0.001) and were hospitalised alive more frequently (P < 0.001). However, the rate of discharge from hospital did not differ significantly between the 2 groups. CONCLUSIONS: "On the basis of 2 treatment regimens during a 12-year survey, we explored the usefulness of adrenaline in out-of-hospital ventricular fibrillation. Both patients with sustained ventricular fibrillation and those who converted to asystole or electromechanical dissociation had an initially more favourable outcome if treated with adrenaline. However, the final outcome was not significantly affected. This study does not confirm the hypothesis that adrenaline increases survival among patients with out-of-hospital cardiac arrest who are found in ventricular fibrillation" (195-201). Researchers in Australia have reported findings consistent with the Swedish physicians cited above. According to the Department of Cardiology, Princess Alexandra Hospital, Brisbane, Australia, (Resuscitation, 1995b), "This trial compared blinded 10 mg aliquots of adrenaline with placebo in 194 cardiac arrest patients treated in hospital using American Heart Association guidelines. In-hospital and out-of-hospital arrests were included. Of the 339 eligible patients a large proportion (145 (45%)) were not randomised and received open 1 mg aliquots of adrenaline. This group is also analysed. Supervising physicians gave significant preference for males, patients with no previous cardiac history and without multiple organ disease to be given open 1 mg adrenaline. Patients in asystole at the time of consideration for entry were preferentially placed in the trial group (114 (69%) vs. 170 (88%)) and patients in ventricular fibrillation were preferentially given open 1 mg adrenaline (31 (21%) vs. 24 (12%) P < 0.03). The most beneficial rhythm changes which led to survival were sinus rhythm and ventricular tachycardia. Analysis of rhythm changes resulting from the dosing showed a significant (P = 0.01) change to a beneficial rhythm with 10 mg adrenaline but not for 1 mg adrenaline or placebo. This was not reflected by an improvement in immediate survival. No significant differences in immediate survival (IS) or hospital discharge (HD) exists between open 1 mg adrenaline (IS 14 (9.7%), HD 3 (2%)) or the 10 mg adrenaline (IS 9 (9.6%), HD 0) vs. placebo (IS 7 (7%), HD 0) trial arms. Patients reaching the point of use of adrenaline have a uniformly poor immediate survival (8.8%) and hospital discharge rate (0.9%). Dosing with 10 mg or 1 mg adrenaline does not influence outcome compared with placebo" (243-249). One may notice in this study, ethical concerns regarding patients needs and risks as a constraint upon pure research. Nonetheless, the findings are consistent with several other studies that show no significant advantage in the use of adrenaline in treating cardiac emergencies. Other recent studies have compared the use of adrenaline with the use of vasopressin, both as a substitute and as an adjunct treatment. According to an Austrian study, "People with a hard-to-treat type of cardiac arrest are three times as likely to survive if they are given a drug called vasopressin than if they receive the standard emergency treatment, adrenaline, doctors in Europe are reporting. "Experts say the information may change the way doctors around the world treat cardiac arrest, which has had dismal survival rates. The condition, often caused by diseased arteries, leads to more than 600,000 sudden deaths a year just in North America and Europe, including about 1,000 a day in the United States. More than half the deaths are in people younger than 65. Cardiac arrest, which is not the same as a heart attack, is a sudden stopping of the heart. But a severe heart attack can lead to cardiac arrest. "The new findings are from a study of 1,186 people in Austria, Germany and Switzerland whose hearts suddenly stopped. The study, directed by Dr. Volker Wenzel of the University of Innsbruck, in Austria, included 44 medical teams and is being published today in The New England Journal of Medicine. "People in the study were not in the hospital when they collapsed, but were treated by emergency teams and then taken to hospitals. The study did not include patients who were revived by electrical shocks delivered by defibrillator machines. It did include patients in whom a defibrillator had failed or was not used because they did not have the kind of abnormal heart rhythm that a shock would help. The patients received the standard emergency treatment for cardiac arrest, including chest compressions and rescue breathing. "To help restart their hearts, the patients were assigned at random to receive either vasopressin or adrenaline, which is also known as epinephrine. If two shots of either medicine did not work, doctors could then give adrenaline, even the patients who had already received it. The two drugs work in similar ways, by constricting blood vessels and raising blood pressure, which plummets in people with cardiac arrest. Both are naturally occurring hormones; adrenaline is made by the adrenal gland, vasopressin by the pituitary. Adrenaline has been used for heart problems for about 100 years. "Over all, the survival rate was the same for the two drugs, 9.9 percent. But they found a striking difference among patients with a condition called asystole, in which there is no pulse and no electrical activity in the heart. It is notoriously hard to treat, doctors say. Asystole causes 20 percent to 40 percent of the sudden deaths in the United States. In the vasopressin group, 12 of 257 survived, 4.7 percent, in contrast to only 4 of 262, 1.5 percent of those who got adrenaline" (paragraphs 1-6). The study goes on to say that "There was also a sharp difference among the patients who needed more than two shots of medicine to get their hearts going again and were given extra adrenaline. That group amounted to nearly two-thirds of the patients in the study. In those who received vasopressin first, 23 of 369 patients survived, 6.2 percent, as compared with 6 of 355, 1.7 percent, in those whose first two shots were adrenaline" (paragraph 7). In an interview supplied for this article, one physician said he had already changed the way he treats patients. "Now, he gives nearly all adults with cardiac arrest both vasopressin and adrenaline" (paragraph 8). The physician, Dr. Wenzel, advocating the use of both medicines, goes on to say: "Get it in there, bang bang, and you either save a life immediately or you dont" (paragraph 8). The researchers cited in this article say, "vasopressin may work better than adrenaline in some cases because it does not deplete desperately needed oxygen in the heart and brain, whereas adrenaline does" (paragraph 9). Clearly it seems that vasopressin is a better choice for the 20 to 30 percent of cardiac arrest victims who are already in asystole when treatment begins. The vasopressin should be used as an adjunct during the asystole phase, and used simultaneously with the adrenaline rather than secondarily. With adrenaline, both in high and low doses, not even measuring up well against placebo studies, vasopressin is starting out with a much better track record in the treatment of cardiac arrest, especially for patients who have entered the asystole phase. References BMJ (1995);310:1091-1094. "Paramedics and technicians are equally successful at managing cardiac arrest outside hospital." British Medical Journal, (29 April). (Online retrieval from http://bmj.bmjjournals.com/cgi/content/full/310/6987/1091) EMS (2004). "Study Finds a Drug That Works Better Than Adrenaline for Some Types of Cardiac Arrest." Courtesy the EMS House of DeFrance http://www.defrance.org Heart (1997);80:412-414 (October) (Online retrieval from http://heart.bmjjournals.com/cgi/content/full/80/4/412. paragraph 2). Resuscitation (1995a) Jun;29(3):195-201 Resuscitation (1995b) Dec;30(3):243-249. Read More