Edward M. Racht

Clinical Prediction Rule for Pulmonary Infiltrates

OBJECTIVE To derive and validate a clinical rule for predicting pneumonic infiltrates in adult patients with acute respiratory illness. DESIGN Prevalence studies in three settings. SETTING Emergency departments of the University of Illinois Hospital at Chicago, the University of Nebraska Medical Center at Omaha, and the Medical College of Virginia at Richmond. PATIENTS Symptoms, signs, comorbidity data, and chest roentgenogram results were recorded for 1134 patients from Illinois (the derivation set), 150 patients from Nebraska, and 152 patients from Virginia (the validation sets). All patients presented to the emergency department and had a chest roentgenogram to evaluate fever or respiratory complaints. MEASUREMENTS AND MAIN RESULTS Within the training set, temperature greater than 37.8 degrees C, pulse greater than 100 beats/min, rales, decreased breath sounds, and the absence of asthma were identified as significant predictors of radiographically proved pneumonia in a stepwise logistic regression model (P = 0.001). The logistic rule discriminated patients with and without pneumonia in the training set with a receiver operating characteristic (ROC) area of 0.82. In the validation sets, the rule discriminated pneumonia and nonpneumonia with ROC areas of 0.82 and 0.76 after adjusting for differences in disease prevalence (P greater than 0.2 compared with the training set). The predicted probability of having pneumonia for patients with different clinical findings corresponded closely with the incidence of pneumonia among patients with such findings in the three settings. CONCLUSIONS Among adults presenting with acute respiratory illness, a prediction rule based on clinical findings accurately discriminated patients with and without radiographic pneumonia, and was used in two other samples of patients without significant decrement in discriminatory ability. This rule can be used by physicians to develop more effective strategies for detecting pneumonia and for helping to determine the need for radiologic study among patients with acute respiratory disease.

Resuscitation in the out-of-hospital setting: Medical futility criteria for on-scene pronouncement of death

The complete and irreversible cessation of life is often difficult to determine with complete confidence in the dynamic environment of out-of-hospital emergency care. As a result, resuscitation efforts often are initiated and maintained by emergency medical services (EMS) providers in many hopeless situations. Medical guidelines are reviewed here to aid EMS organizations with respect to decisions about: 1) initiating or waiving resuscitation efforts; 2) the appropriate duration of resuscitation efforts; and 3) recommended procedures for on-scene or prehospital pronouncement of death (termination of resuscitation). In cases of nontraumatic cardiac arrest, few unassailable criteria, other than certain physical signs of irreversible tissue deterioration, exist for determining medical futility at the initial encounter with the patient. Thus, the general medical recommendation is to attempt to resuscitate all patients, adult or child, in the absence of rigor mortis or dependent lividity. Conversely, well-founded guidelines now are available for decisions regarding termination of resuscitation in such patients once they have received a trial of advanced cardiac life support. In practice, however, the final decision to proceed with on-scene pronouncement of death for these patients may be determined more by family and provider comfort levels and the specific on-scene environment. For patients with posttraumatic circulatory arrest, the type of injury (blunt or penetrating), the presence of vital signs, and the electrocardiographic findings are used to determine the futility of initiating or continuing resuscitation efforts. In general, patients who are asystolic on-scene are candidates for on-scene pronouncement, regardless of mechanism. With a few exceptions, blunt trauma patients with a clearly associated mechanism of lethal injury are generally candidates for immediate cessation of efforts once they lose their pulses and respirations. Regardless of the medical futility criteria, specialized training of EMS providers and targeted related testing of operational issues need to precede field implementation of on-scene pronouncement policies. Such policies also must be modified and adapted for local issues and resources. In addition, although the current determinations of medical futility, as delineated here, are important to establish for societal needs, the individual patients right to live must be kept in mind always as new medical advances are developed.

Management of the violent patient.

Emergency medical services (EMS) providers must often manage violent or combative patients. The data regarding violence against EMS personnel are poor, but according to studies conducted thus far, between 0.8% and 5.0% of incidents to which EMS personnel respond involve violence or the threat of violence. Physical or chemical restraint is usually the only option available to emergency care providers to control violent patients. Physical restraint, however, can lead to sudden death in otherwise healthy patients, possibly as a result of positional asphyxia, severe acidosis, or a patients excited delirium. Chemical restraint has traditionally consisted of either neuroleptics or benzodiazepines, but those drugs also have drawbacks. Haloperidol and droperidol, the neuroleptics most frequently used for restraint, can cause serious side effects such as extrapyramidal symptoms or QTc (QT interval corrected for heart rate) prolongation. The Food and Drug Administration recently issued a black box warning regarding the use of droperidol, because the QTc prolongation associated with the drug has led to fatal torsades de pointes in some patients. Benzodiazepines are also associated with adverse effects, such as sedation and respiratory depression, especially when the drugs are mixed with alcohol. The atypical antipsychotics, a new option that may be available soon, are less likely to cause such effects and therefore may be preferred over the neuroleptics. Liquid and injectable formulations of various atypical antipsychotics are currently in clinical trials. Because few options are currently available to EMS personnel for managing violent patients outside of the hospital, more research regarding violence against emergency care providers is necessary.

Synchronization of Timepieces to the Atomic Clock in an Urban Emergency Medical Services System

STUDY OBJECTIVE Erroneous time documentation of emergency treatment caused by the variation in the accuracy of timepieces has profound medical, medicolegal, and research consequences. The purpose of this study was to confirm the variation of critical timepiece settings in an urban emergency care system noted in previous studies and to implement and monitor the results of a prospective program to improve time synchronization. METHODS Timepieces (n=393) used by firefighters, paramedics, and emergency physicians and nurses were randomly sampled immediately before and at two time intervals (1 and 4 months) after attempted synchronization to the US atomic clock standard. The setting on each timepiece was compared with the atomic clock. From the data, a mathematical simulation estimated the number of time-related documentation errors that would occur in 2,500 simulated cardiac arrest cases using timepieces with accuracy similar to those found in the EMS system before and after attempted synchronization. RESULTS Before attempted synchronization, the timepieces had a mean error of 2.0 (95% confidence interval 1.8 to 2.3) minutes. One month after attempted synchronization, the mean error decreased significantly to .9 (.8 to 1.1) minute. However, it increased to 1.7 (1.5 to 1.9) minutes within 4 months. Mathematical simulation before attempted synchronization predicted that 93% of cardiac arrest cases would contain a documentation error of 2 minutes or more and that 41% of cases would contain a documentation error of 5 minutes or more. Attempted synchronization cut the 2-minute documentation error rate in half and reduced the 5-minute documentation error rate by three fourths. However, the error rates were predicted to return to baseline 4 months after attempted synchronization. CONCLUSION Emergency medical timepieces are often inaccurate, making it difficult to reconstruct events for medical, medicolegal, or research purposes. Community synchronization of timepieces to the atomic clock can reduce the problem significantly, but the effects of a one-time attempted synchronization event are short-lived. [Ornato JP, Doctor ML, Harbour LF, Peberdy MA, Overton J, Racht EM, Zauhar WG, Smith AP, Ryan KA: Synchronization of time-pieces to the atomic clock in an urban emergency medical services system. Ann Emerg Med April 1998;31:483-487.].

Air Medical Services: Future Development as an Integrated Component of the Emergency Medical Services (EMS) System

The use of air medical transport evolved from military experience, initially using fixed wing transport in the Second World War, with the widening use of helicopters initiated in the Korean conflict. Rapid trauma response systems built around helicopters were fully deployed in the Vietnam conflict. The military experience in managing trauma with rapid transport migrated to the civilian arena in the early 1970s. As reported in a white paper by the Foundation for Air Medical Research and Education, cited and presented in Appendix 3:

P REHOSPITAL M ANAGEMENT OF C ARDIAC A RREST : H OW U SEFUL A RE V ASOPRESSOR AND A NTIARRHYTHMIC D RUGS ?

Out-of-hospital resuscitation protocols for patients suffering cardiac arrest have historically included cardiopulmonary resuscitation, defibrillation, and rapid transport to a hospital. For many years, use of drugs to improve myocardial perfusion or to correct arrhythmias that occur during cardiac arrest has been part of prehospital efforts to revive patients in ventricular tachycardia or ventricular fibrillation. Use of some of these drugs, however, may be based more on tradition than on well-documented evidence of efficacy. The authors reviewed pertinent data on the vasopressors epinephrine and vasopressin and the antiarrhythmics amiodarone and lidocaine to evaluate the usefulness of these drugs in cardiac arrest. They found little clinical data supporting the prehospital use of lidocaine in cardiac arrest, and despite a great deal of laboratory and clinical data addressing the efficacy of epinephrine, there is no large, randomized, controlled clinical trial supporting its use. Data on amiodarone and vasopressin support the use of these drugs in out-of-hospital resuscitation efforts.

Multi-agency, prehospital evaluation of the pharyngeo-tracheal lumen (PTL) airway.

INTRODUCTION The purpose of this study was to assess subjectively the performance of the pharyngeo-tracheal lumen (PTL) airway in a multi-agency, prehospital emergency medical service (EMS) environment. METHODS Data were recorded by the EMS provider on 167 [corrected] adult patients (age range 16-92 years) in whom a PTL or endotracheal (ET) airway insertion was attempted. Analysis of variance and Fishers Exact tests were used for statistical analysis. RESULTS There were no significant differences between the PTL and ET groups, either in patient demographics or in rates of successful ventilation with either airway overall or in trauma-related versus non-trauma-related cases, male versus female patients, or volunteer versus paid EMS providers. Basic life support (BLS) providers were able to ventilate successfully with the PTL as frequently as were ALS providers using the ET tube. CONCLUSIONS The PTL appears to be a useful primary airway for BLS providers and for ALS providers who are called upon infrequently to manage an airway acutely. The PTL also may be used as an alternate airway for ALS providers when tracheal intubation cannot be accomplished. Further study is needed to define the effectiveness of the PTL in the management of patients with trauma-related injuries.

Pharmacologic treatment of cardiac arrest.

Antiarrhythmic drugs currently recommended in the American Heart Associations Advanced Cardiac Life Support (ACLS) guidelines for the treatment of cardiac arrest have not been proved in controlled clinical trials to improve survival in patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). Intravenous amiodarone is a promising agent for the treatment of VF and VT. Based on available evidence, amiodarone should be considered for use in patients with shock-refractory ventricular arrhythmias.