One-year survival after prehospital cardiac arrest: the Utstein style applied to a rural-suburban system.

To evaluate the recently published Utstein algorithm (Ann Emerg Med 1991;20:861), the authors conducted a retrospective review of all advanced life support (ALS) trip sheets and hospital records of patients with prehospital cardiac arrests between January 1988 and December 1989. Telephone follow-up was used to determine 1-year survival rates. Of 713 arrests in the 24-month study period, 601 were of presumed cardiac etiology. Approximately 599 of these charts were available for analysis. One hundred ninety-three (32.2%) of these had return of spontaneous circulation (ROSC), 36 (6.0%) survived to hospital discharge, and 24 were alive at 1-year follow-up (4.0% of total or 67% of survivors to discharge). The Utstein style was found to be a useful algorithmic format for reporting prehospital cardiac arrest data in a manner that should allow direct comparison between emergency medical service (EMS) systems. Existing prehospital record-keeping practices (trip sheets) are easily adapted to this style of data collection, although certain data for the template (eg, resuscitations not attempted and alive at 1-year) are more difficult to ascertain. Additionally, the authors report their own experience during a 2-year period, including data that suggest that the majority of patients with cardiac arrest who survive to hospital discharge are still alive at 1 year.

An evaluation of automated defibrillation and manual defibrillation by emergency medical technicians in a rural setting.

We show that automated external defibrillation training of emergency medical technicians (EMTs) is less time consuming than manual defibrillation training, and hypothesize that both improve survival from sudden cardiac death. Data on 91 cardiac arrests over 27 months among five basic life support services was collected before EMT-defibrillation (EMT-D) training. Subsequently, seven BLS services were trained in EMT-D using either manual difibrillation or automated external defibrillation technology, and 55 sudden cardiac death patients were entered after training. Manual defibrillation required 11 more hours per student in initial training. Survival to hospital discharge improved from two of 91 patients (2.2%) in the series before EMT-D training to nine of 55 patients (16.4%) after EMT-D training (P = .001). Improved survival was correlated with shorter prehospital defibrillation times, 8.84 minutes, when EMTs performed defibrillation versus 16.3 minutes before training when EMTs awaited advanced life support defibrillation (P < .001). To enhance equipment familiarity we allowed EMTs to apply three-lead electrode monitors to all medical/cardiac patients during transport (surveillance). There were six emergency medical service-witnessed "surveillance" arrests and three arrests survived to hospital discharge (50% survival). This group represented 33% of all survivors in the series. We recommend automated external defibrillation training for EMTs. Improved survival in sudden cardiac death cases in well-run emergency medical service systems should result from EMT-D training. Finally, we recommend that routine "surveillance" of high-risk patients during transport by defibrillation-capable EMTs be considered in EMT-D programs, rather than limiting EMT-D only to units capable of rapid "man-down" response.

An analysis of invasive airway management in a suburban emergency medical services system.

INTRODUCTION: Airway management is the most critical and potentially life-saving intervention performed by emergency medical service (EMS) providers. Invasive airway management often is required in non-cardiac-arrest patients who are combative or otherwise uncooperative. The success of prehospital invasive airway management in this patient population was evaluated. METHODS: A retrospective review was undertaken of the records of all such patients requiring endotracheal intubation over a three-year period (1987-1989). The study population included 278 patients enrolled by five advanced life support (ALS) units serving a suburban population of 425,000. Field trip sheets were reviewed for diagnosis, intubation method and success, number of intubation attempts, provider experience, reasons for unsuccessful intubations, and complications. RESULTS: A total of 394 invasive airway management attempts were performed on 278 patients. The overall successful intubation rate was 75% (41% orotracheal, 52% nasotracheal, 7% other or unknown). The most common diagnoses were COPD and pulmonary edema (30%) and trauma (24%). Experienced providers were successful on the first attempt in 57% of cases compared to 50% by inexperienced providers (p=.24). Multiple intubation attempts were required in 33% of the patients. There was no statistically significant difference in success rates between the orotracheal and nasotracheal methods (p=.51). The most common reason for unsuccessful intubation was altered level of consciousness. Complications occurred with 7% of successful attempts and in 18% of unsuccessful attempts (p less than .001). Forty-six percent of the patients who were not intubated successfully in the field and required intubation in the emergency department (ED) received a neuromuscular blocking agent prior to successful intubation. CONCLUSION: Prehospital providers can intubate a high but improvable proportion of non-cardiac-arrested patients by both the orotracheal and nasotracheal routes. The use of pharmacologic adjuncts to facilitate the prehospital intubation of selected, non-cardiac-arrested patients is a promising adjunct that needs further evaluation.

An evaluation of pulse oximetry in prehospital care.

STUDY OBJECTIVES: We performed this study to evaluate the accuracy of pulse oximetry oxygen saturation (SpO2) against direct measurements of arterial oxygen saturation (SaO2) in the field. DESIGN: Prospective, cross-sectional, paired measurements of SpO2 against SaO2. SETTING: This evaluation was done in the prehospital setting. INTERVENTIONS: A pulse oximeter with digital probe was used to measure SpO2 in 30 patients. Arterial blood gases were drawn in the field while the pulse oximeter was in use, and oxygen saturation (HbO2) was measured by CO-oximetry. MAIN RESULTS: There was no significant difference between SpO2 (94.6 +/- 5.4%) and HbO2 (94.9 +/- 5.1%) (P = .495, beta less than .2). There was a strong correlation between SpO2 and HbO2 (r = .898). The bias between SpO2 and HbO2 was -0.3, with a precision of 2.4. When SpO2 was 88% or more, HbO2 was 90% or more in every case. Mean carboxyhemoglobin was 1.3 +/- 0.9%, and mean methemoglobin was 0.9 +/- 0.3%. There was no significant difference between the pulse oximeter heart rate and the ECG heart rate (P = .223, beta less than .2). CONCLUSION: We conclude that pulse oximetry is sufficiently accurate to be useful in the field when SpO2 is more than 88%. It is potentially useful in patients with clinical signs of acute hypoxemia and in patients receiving interventions that may produce acute hypoxemia. Further work is needed to evaluate the accuracy of pulse oximetry in the settings of elevated carboxyhemoglobin, methemoglobin, and very low saturations.

Prehospital administration of inhaled metaproterenol.

STUDY OBJECTIVES: We conducted a study of the prehospital use of inhaled metaproterenol. DESIGN, SETTING, TYPE OF PARTICIPANTS, AND INTERVENTIONS: Advanced life support (ALS) providers were trained with a standardized curriculum to identify patients likely to benefit from prehospital inhaled metaproterenol administration. Unit doses of metaproterenol were used in a small-volume nebulizer. We prospectively included 122 patients in an initial study (71 men; age, 63 +/- 19 years) to evaluate the safety and effectiveness of metaproterenol in the field, and 150 patients (including the original 122) in an additional study to evaluate patient selection criteria. MEASUREMENTS AND MAIN RESULTS: The treatments resulted in an increase in peak flows, a decrease in respiratory rates, and no change in heart rates. In 62% of patients, the increase in peak flow exceeded 15%. Wheezing improved in 59% of the patients, worsened in 4%, and did not change in the remainder. Air entry by auscultation improved subjectively in 59% of patients. Mild tremor occurred in 8% of patients, moderate tremor occurred in 1%, and no tremor occurred in the remainder. Significant dysrhythmias did not occur. CONCLUSIONS: ALS providers correctly identified patients for this therapy. No technical problems were encountered in the field with this treatment approach. We conclude that ALS providers can be taught to identify patients likely to benefit from inhaled metaproterenol, that inhaled metaproterenol can be administered in the field, and that metaproterenol is both safe and effective when used in the prehospital setting.

Out-of-hospital cardiac arrest: a six-year experience in a suburban-rural system.

All out-of-hospital cardiac arrest advanced life support (ALS) trip sheets were collected from January 1980 through December 1985 for this suburban-rural system. Information was extracted according to a uniform reporting format. In our study, 18% of patients with early CPR (less than four minutes) and early ALS (less than ten minutes) survived to hospital discharge, compared with 7% with early CPR and late ALS, 6% with late CPR and early ALS, and 3% with both occurring late. Although 75% of the survivors had ventricular tachyarrhythmias as initial rhythms, bradyasystolic arrests were not uniformly lethal, even with long CPR and ALS times. This study supports the need for early CPR in the prehospital care of potential sudden-death victims. We recommend, with qualification, this reporting format to emergency medical services systems to describe their cardiac arrest experience.

Conjunctival oxygen tension monitoring during a controlled phlebotomy.

A decrease in the conjunctival oxygen tension (Pcjo2) and conjunctival index (Pcjo2/Pao2) has been shown to be an early marker of acute blood loss. We sequentially measured Pcjo2, Pcjo2/Pao2, blood pressure, and pulse rate in five healthy adults after controlled phlebotomy of 450 mL and after intravenous fluid repletion. No significant changes occurred in either the Pcjo2 or Pcjo2/Pao2 after phlebotomy or after fluid replacement. We conclude that a blood loss of 450 mL in healthy, euvolemic adults is insufficient to perturb the conjunctival index. The lower limits of sensitivity of changes in Pcjo2 and Pcjo/Pao2 in response to acute blood loss remain to be established.