Daniel Hankins

High Discharge Survival Rate After Out-of-Hospital Ventricular Fibrillation With Rapid Defibrillation by Police and Paramedics

STUDY OBJECTIVE To assess outcome in patients with ventricular fibrillation (VF) treated by defibrillator-equipped police and emergency medical technician-paramedics in an advanced life support (ALS) emergency medical services (EMS) system. METHODS We carried out a retrospective observational outcome study of all consecutive adult patients with atraumatic cardiac arrest treated from November 1990 through July 1995. The study was carried out in a city with a population of 76,865 in an area of 32.6 square miles. Central 911 dispatched police and an ALS ambulance simultaneously. Accurate intervals were obtained with the synchronization of all defibrillator clocks with the 911 dispatch clock. The personnel who arrived first delivered the initial shock. After shocks delivered by police, paramedics provided additional treatment if needed. Main outcome measures were time elapsed before delivery of the first shock, restoration of spontaneous circulation (ROSC), and survival to discharge home. RESULTS Of 84 patients, 31 (37%) were first shocked by police. Thirteen of the 31 demonstrated ROSC, without need for ALS treatment. All 13 survived to discharge. The other 18 patients required ALS; 5 (27.7%) survived. Among the 53 patients first shocked by paramedics, 15 had ROSC after shocks only, and 14 survived. The other 38 needed ALS treatment; 9 survived. Call-to-shock time for all patients was less in the police group than in the paramedic group (5.6 versus 6.3 minutes, P = .038). For all patients, call-to-shock time was less in those with ROSC after shocks only than in those who needed ALS (5.4 versus 6.3 minutes, P = .011). Survival to discharge was 49% (41 of 84), with 18 of 31 (58%) in the police group and 23 of 53 (43%) in the paramedic group. Call-to-shock time for survivors was 5.8 minutes; it was 6.4 minutes for the nonsurvivors (P = .020). Neither ROSC nor discharge survival was significantly different between police and paramedic-shocked patients. ROSC after initial shock and call-to-shock time were major determinants of survival, whether the first shocks were administered by police or by paramedics. With ROSC after shocks only, 27 of 28 (96%) survived, whereas 14 of 56 (25%) needing ALS survived (P < .001). CONCLUSION A high discharge-to-home survival rate was obtained with early defibrillation by both police and paramedics. When shocks resulted in ROSC, the overwhelming majority of patients survived (96%). Even brief time decreases (eg. 1 minute) in call-to-shock time increase the likelihood of ROSC from shocks only, with a consequent decrease in the need for ALS intervention. Short call-to-shock time and ROSC response to shocks only are major determinants of a high rate of survival after VF.

Seven years' experience with early defibrillation by police and paramedics in an emergency medical services system.

PRIMARY OBJECTIVE To assess the outcome of patients with out-of-hospital cardiac arrest with ventricular fibrillation as the presenting rhythm in an emergency medical services system utilizing a combined police/paramedic response to provide early defibrillation. MATERIALS AND METHODS Police and paramedics were dispatched from law enforcement and ambulance communications centers, respectively. First-arriving personnel delivered initial shocks, all using automated external defibrillators. Patients were classified according to response to initial shocks: restoration of pulses with shocks only or in need of advanced life support, including epinephrine. Discharge survival was defined as return to home without disabling neurologic injury. RESULTS Over the 7-year period of study 131 patients presented with ventricular fibrillation: 58 were first treated by police and 73 by paramedics. Restoration of pulses with shocks only and discharge survival were not different in police and paramedic groups, with overall survival of 40% (53 of 131 patients). Among the survivors, 19% (18/95 patients) obtained a spontaneous circulation only after administration of epinephrine and other ALS interventions. CONCLUSION Both restoration of a functional circulation, without need for advanced life support interventions, and discharge survival without neurologic disability are very dependent upon the rapidity with which defibrillation is accomplished, regardless of who delivers the shocks. In addition, a smaller but significant number of patients who require ALS interventions, including epinephrine, for restoration of a spontaneous circulation survive to discharge. Short time differences, on the order of 1 min, are significant determinants of both immediate response to shocks and discharge survival.

Patient outcomes following defibrillation with a low energy biphasic truncated exponential waveform in out-of-hospital cardiac arrest

PRIMARY OBJECTIVE To determine the outcome of patients with out-of-hospital cardiac arrest and ventricular fibrillation as the presenting rhythm while using automated external defibrillators (AEDs) that delivered non-escalating, impedance-compensated low-energy (150 J) shocks. MATERIALS AND METHODS AEDs delivering low-energy biphasic truncated exponential (BTE) shocks were employed in an emergency medical services (EMS) system in which first-arriving personnel - police, firefighters or paramedics - delivered the initial shocks. Patients were classified according to their response to shocks: restoration of sustained spontaneous circulation (ROSC) without need for epinephrine and other advanced life support (ALS) interventions; and ALS, those requiring epinephrine in all instances. The primary end-point was neurologically-intact discharge survival. Secondary end-points were ROSC with shocks only and the call-to-shock time interval. RESULTS Of 42 patients with VF arrest treated with BTE shocks, 35 were bystander-witnessed. Of these 35, 14 (38%) regained a sustained ROSC on-scene with shocks only, needing no epinephrine for ROSC. All 14 survived to discharge home. Of the remaining 21 patients needing ALS intervention, only two (9.5%) survived to discharge. Overall, 16/35 patients (46%) survived to discharge home, an outcome comparable to our experience with patients treated with escalating high-energy monophasic waveform shocks. CONCLUSIONS Low-energy (150 J) non-escalating biphasic truncated exponential waveform shocks terminate VF in out-of-hospital cardiac arrest with high efficacy; patient outcome is comparable with that observed with escalating high-energy monophasic shocks. Low-energy shocks, in addition to high efficacy, may confer the advantage of less shock-induced myocardial dysfunction, though this will be difficult to define in the clinical circumstance of long-duration VF provoked by a pre-existing diseased myocardial substrate.

Thoracic aortography following blunt chest trauma

The records of 314 patients who suffered blunt chest trauma and underwent thoracic aortography between 1968 and 1986 were retrospectively reviewed. The patients ranged in age from 7 to 84 years (mean, 37.7 years). There were 255 male and 59 female patients. The majority of injuries were the result of motor vehicle accidents. The most common indication for aortography was a widened mediastinum on chest roentgenogram (83.4%). The aortogram was positive for cardiovascular injury in 19.7% of cases. There were 47 patients with aortic rupture, 15 with subclavian artery disruption, and 1 with traumatic aortic insufficiency. Complications occurred in 1.7% of patients. Two patients sustained groin hematomas and one patient suffered an intimal tear of the ascending aorta from the angiographic catheter. None of the complications required treatment. Aberrant origin of the arch vessels occurred in 0.96% of patients, and ductus diverticulum occurred in 0.64%. There were two false-positive and no false-negative aortograms. It was concluded that thoracic aortography after trauma is accurate and safe.

Spinal immobilization in the field: clinical clearance criteria and implementation.

Awareness of the health and financial repercussions of unnecessary immobilization has made cervical spinal immobilization controversial in out-of-hospital care. Clinical criteria for clearance of the cervical spine in the hospital based on mechanism of injury have been supported by many trauma centers. However, implementation of clinical criteria for cervical spinal clearance in out-of-hospital settings is not as well validated by multicenter studies or accepted by many emergency departments. This consensus group recommends that clinical criteria to determine “low-risk” patients be available for use by emergency medical services providers in out-of-hospital settings; however, training, audits, quality management, integration into the medical community, and extent of program implementation should be decided based on individual emergency medical services systems.

Evaluation of the i-STAT portable clinical analyzer for use in a helicopter

We evaluated the performance of the i-STAT Portable Clinical Analyzer (PCA) for use in a helicopter with the analyses performed by the flight nurses. Imprecision and initial split-sample comparative studies were performed in the Hospital Laboratory and Clinical Chemistry Laboratory. Day-to day imprecision (CV) ranged from 0.5 to 6.7% in the clinical laboratories and 0.5 to 5.3% in the helicopter with urea nitrogen and glucose determinations giving the highest values. Comparison studies between the PCA and the Kodak Ektachem E700 and the Beckman Astra 8 gave acceptable results, although urea nitrogen did show a bias in the high range (mean difference 4.91 and 3.69 mmol/L respectively). It was not considered medically significant for the anticipated patient population of the PCA in our hospitals. Comparison studies of patient specimens between the PCA in the helicopter and the clinical laboratories showed no significant differences, with the exception of glucose. Lower glucose values were obtained in the laboratory due to the time lag between specimen collection in the helicopter and analysis in the laboratory.

Air Medical Transport of Trauma Patients

This report reviews the current status of air medical transportation of trauma patients. Aspects reviewed include patient care, dispatch, safety, andpossible future directions in air medical patient care.

Appropriate and Safe Utilization of Helicopter Emergency Medical Services: A Joint Position Statement with Resource Document

Abstract This position statement with accompanying resource document is the result of a collaborative effort of a writing group comprised of members of the Air Medical Physician Association (AMPA), the American College of Emergency Physicians (ACEP), the National Association of EMS Physicians (NAEMSP), and the American Academy of Emergency Medicine (AAEM). This document has been jointly approved by the boards of all four organizations. Patients benefit from the appropriate utilization of helicopter emergency medical services (HEMS). EMS and regional health care systems must have and follow guidelines for HEMS utilization to facilitate proper patient selection and ensure clinical benefit. Clinical benefit can be provided by Meaningfully shortening the time to delivery of definitive care to patients with time-sensitive medical conditions Providing necessary specialized medical expertise or equipment to patients before and/or during transport Providing transport to patients inaccessible by other means of transport The decision to use HEMS is a medical decision, separate from the aviation determination whether a transport can be completed safely. Physicians with specialized training and experience in EMS and air medical transport must be integral to HEMS utilization decisions, including guideline development and quality improvement activities. Safety management systems must be developed, adopted, and adhered to by air medical operators when making decisions to accept and continue every HEMS transport. HEMS must be fully integrated within the local, regional, and state emergency health care systems. HEMS programs cannot operate independently of the surrounding health care environment. The EMS and health care systems must be involved in the determination of the number of HEMS assets necessary to provide appropriate coverage for their region. Excessive resources may lead to competitive practices that can affect utilization and negatively impact safety. Inadequate resources will delay receipt of definitive care. National guidelines for appropriate utilization of HEMS must be developed. These guidelines should be national in scope yet allow local, regional, and state implementation. A National HEMS Agenda for the Future should be developed to address HEMS utilization and availability and to identify and support a research strategy for ongoing, evidence-based refinement of utilization guidelines. Key words: appropriateness; helicopter; HEMS; safety; utilization

Profound acidosis caused by isoniazid ingestion

Isoniazid (INH) is the cause of one of the most common serious drug overdoses and can cause severe metabolic acidosis. We report a case of INH overdose that is most notable because the patient survived without apparent sequelae after experiencing an extremely low pH level (6.49). This is the lowest reported pH level with patient survival. Toxicity and pharmacology of INH and various aspects of metabolic acidosis are discussed.

Epinephrine use and outcomes in anaphylaxis patients transported by emergency medical services

BACKGROUND Anaphylaxis is a potentially life-threatening allergic reaction that may require emergency medical system (EMS) transport. Fatal anaphylaxis is associated with delayed epinephrine administration. Patient outcome data to assess appropriateness of EMS epinephrine administration are sparse. OBJECTIVES The objectives of this study are to (1) determine the frequency of epinephrine administration in EMS-transported patients with allergic complaints, (2) identify predictors of epinephrine administration, and (3) determine frequency of emergency department (ED) epinephrine administration after EMS transport. METHODS A cohort study was conducted from over 5 years. A total of 59187 EMS transports of an Advanced Life Support (ALS) ambulance service were studied. RESULTS One hundred and three patient transports for allergic complaints were analyzed. Fifteen patients received EMS epinephrine, and epinephrine was recommended for 2 additional patients who refused, for a total of 17 (17%) patients for whom epinephrine was administered or recommended. Emergency medical system epinephrine administration or recommendation was associated with venom as a trigger (29% vs 8%; odds ratio [OR], 4.70; 95% confidence interval [CI], 1.28-17.22; P = .013), respiratory symptoms (88% vs 52%; OR, 6.83; 95% CI, 1.47-31.71; P = .006), and fulfillment of anaphylaxis diagnostic criteria (82% vs 49%; OR, 3.50; 95% CI, 0.94-13.2; P = .0498). Four (4%) patients received epinephrine after ED arrival. CONCLUSION Low rates of epinephrine administration were observed. The association of EMS administration of epinephrine with respiratory symptoms, fulfillment of anaphylaxis diagnostic criteria, and low rate of additional epinephrine administration in the ED suggest that ALS EMS administered epinephrine based on symptom severity. Additional studies of EMS anaphylaxis management including ED management and outcomes are needed.