Jerris R Hedges

Succinylcholine-assisted intubations in prehospital care

Although endotracheal intubation is considered the optimal technique for airway management in critically ill patients, performance of this task in the prehospital setting is at times difficult due to increased masseter muscle tone, vocal cord spasm, or patient combativeness. Use of short-acting paralyzing agents by paramedics to facilitate intubation in these situations is an uncommon practice. We report the recent experience of an emergency medical service system that has used succinylcholine (SUX) for more than ten years. We reviewed prehospital patient intubations for two years; 215 patients were intubated by paramedics without the use of SUX and 95 patients were intubated with the use of SUX. The patient group intubated with SUX was characterized by a greater percentage of women (48% vs 35%; P less than .05), a higher mean Glasgow Coma Scale score (8.6 vs 3.4), fewer intubations for cardiac arrest (3% vs 81%), and more hospital survivors (58% vs 24%; P less than .005). The groups were not different with respect to mean age or frequency of trauma. Paramedics chose to use SUX in 69% of nonarrested patients requiring intubation. SUX-assisted intubation was used most often for the indications of airway protection and respiratory distress. Review of hospital records showed no difference between the groups for frequency of either aspiration pneumonia or mechanical ventilation in patients surviving to hospital admission. No patient receiving SUX required emergency cricothyrotomy, nor was esophageal intubation noted in either group. Succinylcholine-assisted intubation was used safely and selectively by the paramedics in this EMS system to permit airway control and ventilation of patients with more difficult intubations.

Myoglobin as an early indicator of acute myocardial infarction

The ECG and the determination of serum enzymes creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) may be falsely normal early in acute myocardial infarction. Myoglobin, an oxygen-carrying protein found in cardiac muscle and striated skeletal muscle, presents an attractive alternative to CPK and LDH in the emergency department setting for identification of acute myocardial infarction. Myoglobin levels may be elevated in the serum within one hour after myocardial cell death with peak levels reached within four to six hours. We report a study of 59 patients presenting to a community hospital with chest pain and subsequent hospitalization. Twenty-one had an acute myocardial infarction. Presenting (0 hour) myoglobin determination was positive in 13 of 21 individuals, while CPK-MB was positive in only three. Serum myoglobin elevation at three hours identified all 21 patients with myocardial infarction with the CPK-MB determination positive in 19. Serum myoglobin elevation may permit early identification of myocardial infarction, with subsequent verification using CPK-MB determination, allowing appropriate intensive care admission for careful monitoring of these patients.

Prehospital use of neuromuscular blocking agents in a helicopter ambulance program

We prospectively studied the use of succinylcholine chloride and pancuronium bromide by the physician/nurse flight team of our hospital-based helicopter ambulance service. Patients who received these agents at the scene of an accident (prehospital group, n = 39) were compared with patients who were paralyzed by the flight team in the emergency department of transferring hospitals (control group, n = 35). By protocol, succinylcholine was used primarily for endotracheal intubation and pancuronium for prolonged paralysis after endotracheal intubation. Seventy-four patients received one or both agents. Overall, 61 of 74 patients had intracranial pathology as their primary diagnosis (82%). Endotracheal intubation was the primary indication for paralysis in the majority of patients (67 of 74), although intracranial pressure control, ventilation, agitation control, and seizure control were frequent secondary indications. Prior intubation attempts had failed in 40 of 74 patients (54%). After paralysis, intubation was successful in 68 of 71 patients (96%). Serious complications (ie, dysrhythmia requiring drug therapy) occurred in three patients but resolved with appropriate therapy in each case. Minor complications (ie, dysrhythmia not requiring drug therapy, histamine flush, infiltrated IV line) occurred in 18 patients. There was no significant difference in successful intubation or complication rate between the prehospital and control group. Paralysis allowed airway stabilization in a significant number of critically ill patients who could not otherwise be endotracheally intubated, with a lower incidence of complications than has been previously reported for ED patients. These results suggest that neuromuscular blocking agents can be used safely and effectively at accident scenes by a physician/nurse team.

A comparison of blind nasotracheal and succinylcholine-assisted intubation in the poisoned patient

In the patient obtunded by drug intoxication, the optimal method of airway protection prior to gastric emptying is not clear. We report a prospective randomized trial of two methods of intubation in this patient population. Fifty-two overdose patients with Glascow Coma Scale scores of 12 or less were intubated either orotracheally after succinylcholine administration or nasotracheally. Success rate, time to intubate, difficulty, and complications of intubation were compared for the two groups. We found a success rate of 100% (23 of 23) for succinylcholine assisted intubation (SAI) versus 65% (19 of 29) success with blind nasotracheal intubation (BNI). Mean time to intubate was 64 seconds and 276 seconds in the SAI and BNI groups, respectively. Eighty-six percent (19 of 22) of patients were intubated successfully in less than 120 seconds in the SAI group versus 37% (10 of 27) in the BNI group (P less than .005). In the SAI group, the mean number of attempts was 1.3 per patient, (range, one to three) with 96% (22 of 23) having two or fewer attempts. No complications were identified. In the BNI group, the mean number of attempts was 3.7 per patient, (range, one to 13) with 45% (13 of 29) having two or fewer attempts (P less than .005). Sixty-nine percent of the BNI group experienced epistaxis, 17% had vomiting, and 10% aspirated. We conclude that SAI is a safe and effective method of airway protection in the obtunded poisoned patient. Complications and difficulty in intubation were significantly less with SAI than with blind nasotracheal intubation.

A chest pain clinic to improve the follow-up of patients released from an urban university teaching hospital emergency department

During a 12-month period, 1,045 of 1,554 patients (67%) over age 30 seen in an urban teaching hospital emergency department with acute chest pain were released based on the clinical judgment of the examining physician. Patients who were released were offered follow-up within 24 to 72 hours in a hospital-based chest pain clinic. Of these 1,045 patients, 772 (74%) returned or were contacted by phone, and 29 were directly admitted; 14 had unstable angina, and eight had new myocardial infarctions. Because of its positive impact on the quality of care at an acceptable cost, the Chest Pain Clinic, which was originally instituted as part of a research protocol, has now become part of the routine spectrum of care provided at the University of Cincinnati Medical Center.

Use of cardiac enzymes identifies patients with acute myocardial infarction otherwise unrecognized in the emergency department

Recognition of an acute myocardial infarction in the patient with chest pain is a frequent challenge to the clinician. Previous studies suggest that cardiac enzymes are of limited value in identifying patients with acute MI in the emergency department. Such studies have not evaluated the use of cardiac enzyme tests to complement decision making in the population of patients clinically designated for ED release. We studied 773 ED visits by patients age greater than or equal to 30 years presenting with chest pain unexplained by thoracic trauma or radiographic abnormalities. Cardiac enzyme levels were not available to the clinicians at the time of the initial visit and disposition of these patients was determined solely by clinical and ECG evaluation. Of the 291 admitted patients, 46 had an MI; 22 of the MI patients had a normal creatine kinase (CK) level. Of the 482 patients released from the ED, 181 patients had an elevated CK level. Among the released patients were five patients with MI. Four released MI patients had a CK level greater than or equal to 200 IU/L and three had an elevated CK-MB fraction (greater than or equal to 12 IU/L). In the population of patients scheduled for release, an elevated CK-MB had sensitivity, specificity, and positive predictive value for MI of 60%, 100%, and 60%, respectively. Although cardiac enzymes cannot be used in isolation to make admission decisions, selective use of CK-MB for final screening of patients otherwise scheduled for ED release may enhance the initial admission of patients with MI at risk for unintentional release.

Prehospital trial of emergency transcutaneous cardiac pacing.

A prospective alternate-day controlled trial of prehospital transcutaneous cardiac pacing (PACE) of hemodynamically significant bradycardia and asystole was undertaken. All patients had a Glasgow coma scale score of 12 or less. Patients in the control group (n = 101) received standard advanced cardiac life support (ACLS) care. Patients in the pacing group (n = 101) were to receive PACE in addition to standard ACLS treatment; 89 patients were actually paced. The two groups were comparable in terms of age, sex, presenting rhythm, and mean times to cardiopulmonary resuscitation (CPR) and ACLS. For the 144 patients in whom the time of arrest could be estimated, the mean times to CPR and ACLS were 5.3 +/- 4.0 and 10.9 +/- 7.1 min, respectively. For the 65 paced patients in whom the time of arrest could be estimated, the mean time from arrest to pacing was 21.8 +/- 8.8 min (range 2 to 43). Multivariate analysis of outcome variables (presentation to emergency department with a pulse, admission to the hospital, and discharge from the hospital) revealed that an initial rhythm of ventricular tachycardia or fibrillation and a short time to ACLS were correlated with a favorable outcome (p less than .05; logistic regression analysis). A short time to PACE was associated with admission to the hospital (p = .20; logistic regression analysis). The use of a stand-alone transcutaneous pacing device in the prehospital arrest setting was associated with generally long times until pacing and did not appreciably improve outcome. Use of PACE in patients demonstrating prehospital bradycardia without neurologic impairment remains to be evaluated.

Factors contributing to paramedic onscene time during evaluation and management of blunt trauma

Prehospital patient management decisions are complex because the traumatized patient population is heterogeneous with respect to demographics, mechanism of injury, physiological response to injury, and time from injury to medical care. One hundred and nine blunt trauma patient evaluations by paramedics in a county-wide semirural emergency medical services (EMS) system were analyzed to determine paramedic time on the scene and the factors that might influence onscene time. Onscene time linearly correlated with a prolonged transport time. Hemodynamic and respiratory dysfunction were also associated with increased onscene time. Mean onscene time was not significantly different between high (greater than 13) and low (less than or equal to 13) trauma score (TS) groups, although patients with low TS did receive more interventions (more intravenous lines, more frequent intubation, and more frequent pneumatic antishock garment use). Similar results were found when high (greater than 10) and low (less than or equal to 10) Glasgow Coma Scale (GCS) groups were compared. The correlation of emergency department TS with initial prehospital TS and onscene time demonstrated a small improvement in TS with increasing onscene time for the patient with an initial TS greater than or equal to 13. However, patient groups with either a low TS or a low GCS score showed no significant improvement in TS with increasing onscene time. Without a strict management algorithm, paramedics use a variety of cues to guide their actions during the onscene management of blunt trauma. Future studies should address the impact of strict management algorithms on onscene time and ultimate patient outcome.

Use of ancrod in acute or progressing ischemic cerebral infarction

Ancrod has been used in Europe for over 15 years for peripheral vascular disease, deep vein thrombosis, and central retinal venous thrombosis, and in patients at risk for thromboembolism. In a double-blind, randomized, placebo-controlled study at University Hospitals in Cincinnati, 20 acute cerebral infarction patients received a series of IV infusions of ancrod (ten) or placebo (ten) for seven days. Early fibrinolysis with a small decrease in fibrinogen was observed, and d-dimers were elevated at four hours, indicating early clot lysis. At three months, patients with moderate to severe strokes (less than 40 on the Scandinavian Stroke Scale) in the ancrod group showed average improvement by a factor of 3 over the placebo group. No bleeding, abnormal laboratory results, or deaths occurred, but ancrod was discontinued in one patient who had seizures. As a result of this study, a double-blind multicenter international clinical trial to further assess the safety and effectiveness of ancrod is being planned.

Central versus peripheral intravenous routes in cardiopulmonary resuscitation

The central venous (CV) and peripheral venous (PV) routes of drug administration are generally considered to be equally effective during cardiopulmonary resuscitation (CPR). This canine study compared simulated drug delivery via CV and PV routes during CPR. The CV group dogs had a CV catheter placed via the external jugular vein, and the PV group dogs had a PV catheter placed in the distal forelimb. Thirty seconds after the induction of cardiac arrest with KCl, CPR was begun with a gas-powered chest compressor with ventilations after every fifth compression. Sixty seconds later, a 0.5 ml bolus of technetium 99m-labeled serum albumin was given. Time activity curves were obtained over the right and left ventricles. The mean time for the counts to rise to half the left ventricular peak (T1/2LV) was significantly less for the CV group than for the PV group (P less than 0.05), averaging 11 and 84 seconds, respectively. The time to left ventricular peak (TLV) was also statistically shorter for the CV group than the PV group, averaging 118 versus 258 seconds, respectively. This study demonstrates that central venous administration is more rapid than peripheral venous administration during CPR and supports the preferential use of the central venous route for drug administration clinically.