Eric E. Harrison

Lidocaine in Prehospital Countershock Refractory Ventricular Fibrillation

Drug management of out-of-hospital countershock refractory ventricular fibrillation was evaluated by including 100 mg lidocaine bolus intravenously as the only anti-arrhythmic option in a protocol for use by paramedics. One hundred sixteen patients entered the study by failing to convert from ventricular fibrillation after the sequence of countershock, sodium bicarbonate, and repeat countershock. Sixty-two patients (53%) received lidocaine during the course of attempted resuscitation (Group I); 54 patients (47%) did not receive lidocaine (Group II). The two groups did not have significant differences in response times, patient profiles, or the use of other drugs or procedures. In Group I, 28 patients (45%) remained in ventricular fibrillation on arrival at the hospital, 15 (24%) were admitted to the CCU, and seven (11%) were ultimately discharged. In Group II, 25 patients (46%) remained in ventricular fibrillation on arrival at the hospital, eight (17%) survived to be admitted to the hospital, and one (2%) was ultimately discharged. The ability to convert ventricular fibrillation and the number of short- and long-term survivors did not differ significantly between the two groups. We conclude that a well-documented, controlled study of prehospital drug management of ventricular fibrillation is possible, and that further clinical evaluation of drug use in countershock refractory ventricular fibrillation is needed.

Esophageal Perforation Following Use of the Esophageal Obturator Airway

Four cases of esophageal rupture associated with the use of the esophageal obturator airway are presented and added to the fifteen cases already in the literature. The incidence of this complication may be greater than previously suspected since a systematic search for this complication has not been made in cardiac arrest patients. The mechanism of rupture of the occluded esophagus may be similar to that seen in postemetic rupture. Endotracheal intubation remains the procedure of choice in airway control of cardiac arrest patients, although the modified esophageal obturator airway with gastric tube may prevent the occurrence of esophageal rupture by allowing decompression of the esophagus.

Prehospital administration of nitrous oxide for control of pain

The effects of 50% nitrous oxide and 50% oxygen and of 30% nitrous oxide and 70% oxygen were evaluated in 88 patients with significant pain while in the prehospital setting. Under the telemetry physicians supervision, EMT-Ps directed patients in the technique of self-administration of the analgesic gas. Fifty percent (36/72) reported complete or almost complete amelioration of pain; all but 15% (11/72) reported some degree of relief. No patients experienced clinically deleterious side effects, although 48% (41/85) reported side effects, of which 90% were mild. The analgesic properties, lack of complications, quick onset and short duration of action, and acceptance by patients, physicians, and paramedics make N2O a nearly ideal analgesic agent for advanced life support use in the prehospital relief of significant pain.

Use of calcium in electromechanical dissociation

Calcium is recommended by American Heart Association standards for the resuscitation of patients with electromechanical dissociation (EMD). Until recently, only anecdotal case reports were offered to support this recommendation. Recent studies examining the question of whether calcium is useful in resuscitating hearts in EMD are reviewed.

The use of bretylium in prehospital ventricular fibrillation.

Bretylium tosylate is recommended by the American Heart Association Standards for Advanced Cardiac Life Support for refractory ventricular fibrillation after countershock, sodium bicarbonate, and epinephrine. According to this protocol, paramedics gave five to six milligrams per kilogram of intravenous bretylium by bolus in 96 patients with refractory fibrillation over a 24-month period. A positive response was defined as the presence of a palpable pulse following bretylium and countershock. Thirty-five percent of patients (34/96) responded following bretylium. Twenty-one percent (20/96) responded only temporarily with a rhythm and pulse. Fifteen percent (14/96) maintained a stable rhythm and vital signs on admission to the hospital, but only five patients, 5% of the total population, (5/96), were eventually discharged home. Clinical variables were similar in non-responders, temporary responders, and those admitted, but the times from the onset of Advanced Cardiac Life Support to receiving bretylium were 23.5 min, 20.3 min, and 14.3 min respectively. We conclude that about one-third of patients in refractory ventricular fibrillation respond following bretylium and countershock and that earlier bretylium use may give better results.

Paramedic use of intracardiac medications in prehospital sudden cardiac death.

The intracardiac administration of medications in cardiac arrest is advocated when an intravenous route cannot be established. Although warnings of complications of this mode of therapy are reiterated throughout the literature, their careful documentation is lacking. Paramedics were trained to administer intracardiac medications, under strict criteria, in patients with prehospital sudden cardiac death. Long-term survivors who received intracardiac medications from paramedics were compared to a control group resuscitated by paramedics with intravenous medications alone. By far, the patients who received intracardiac medications were more nearly refractory to resuscitation because of the criteria for intracardiac medication use. Potential complications of the intracardiac route were identified and sought. However, complications were no more common in this group of patients than in the control group. Paramedics can successfully administer intracardiac medications when indicated.

Coexisting right and left hypertrophic subvalvular stenosis and fixed left ventricular outflow obstruction due to aortic valve stenosis

A case of fixed left ventricular outflow tract obstruction due to aortic valve stenosis coexisting with right- and left-sided subvalvular hypertrophic stenosis is documented with hemodynamic data, angiograms, echocardiograms and findings at surgery. Histologic examination of the septal muscle with light and electron microscopy revealed hypertrophy of the muscle but none of the characteristics of idiopathic hypertrophic subaortic stenosis. Septal hypertrophy with subvalvular obstruction can occur secondary to left ventricular pressure overload due to fixed left ventricular outflow tract obstruction and is not always the chance occurrence of two separate diseases.

Onset of Prinzmetal's angina two years following sudden death syndrome survival

A patient who was resuscitated after an episode of ventricular fibrillation without myocardial infarction outside the hospital developed angina for the first time two years later. Although the clinical pattern did not fulfill all of the criteria of Prinzmetals variant angina and was found to correspond with episodes of ventricular tachycardia, we feel that Prinzmetals angina can be implicated as the mechanism of previos ventricular fibrillation. During the patients second hospitalization, angiography demonstrated a single, moderately stenotic, right coronary lesion which was bypassed. Immediately postoperatively, the patient developed ventricular fibrillation requiring more than two hours of cardiopulmonary resuscitation. Six months after bypass surgery, she experienced an inferior wall myocardial infarction. She is presently asymptomatic with normal heart size.