Ron M. Walls

Cardiac troponin I as a predictor of major cardiac events in emergency department patients with acute chest pain

OBJECTIVES We sought to evaluate the diagnostic and prognostic value of cardiac troponin I (cTnI) in emergency department (ED) patients with chest pain. BACKGROUND Although cTnI has been shown to correlate with an increased risk for complications in patients with unstable angina, the prognostic significance of this assay in the heterogeneous population of patients who present to the ED with chest pain is unclear. METHODS cTnI and creatine kinase-MB fraction (CK-MB) mass concentration were collected serially during the first 48 h from onset of symptoms in 1,047 patients > or =30 years old admitted for acute chest pain. Sensitivity, specificity and receiver operating characteristic curves were calculated for cTnI and CK-MB collected in the first 24 h. RESULTS The sensitivity, specificity and positive predictive value of cTnI for major cardiac events were 47%, 80% and 19%, respectively. Among patients were who ruled out for myocardial infarction, cTnI was elevated in 26% who had major cardiac complications compared with 5% for CK-MB; the positive predictive value for an abnormal cTnI result was 8%. Elevated cTnI in the presence of ischemia on the electrocardiogram was associated with an adjusted odds ratio of 1.8 (95% confidence interval 1.1 to 2.9) for major cardiac events within 72 h. Among patients without a myocardial infarction or unstable angina, cTnI was not an independent correlate of complications. CONCLUSIONS In patients presenting to the ED with acute chest pain, cTnI was an independent predictor of major cardiac events, However, the positive predictive value of an abnormal assay result was not high in this heterogeneous cohort.

Evaluation of the Time Saved by Prehospital Initiation of Reteplase for ST-Elevation Myocardial Infarction Results of the Early Retavase-Thrombolysis In Myocardial Infarction (ER-TIMI) 19 Trial

OBJECTIVES The Early Retavase-Thrombolysis In Myocardial Infarction (ER-TIMI) 19 trial tested the feasibility of prehospital initiation of the bolus fibrinolytic reteplase (rPA) and determined the time saved by prehospital rPA in the setting of contemporary emergency cardiac care. BACKGROUND Newer bolus fibrinolytics have undergone only limited evaluation for prehospital administration. In addition, as door-to-drug times have decreased, the relevance of findings from prior trials of prehospital fibrinolysis has become less certain. METHODS Patients (n = 315) with ST-elevation myocardial infarction (STEMI) were enrolled in 20 emergency medical systems in North America. The time from emergency medical service (EMS) arrival to administration of a fibrinolytic was compared between study patients receiving prehospital rPA and sequential control patients from 6 to 12 months before the study who received a fibrinolytic in the hospital. RESULTS Acute myocardial infarction was confirmed in 98%. The median time from EMS arrival to initiation of rPA was 31 min (25th to 75th percentile, 24 min to 37 min). The time from EMS arrival to in-hospital fibrinolytic for 630 control patients was 63 min (25th to 75th percentile, 48 min to 89 min), resulting in a time saved of 32 min (p < 0.0001). By 30 min after first medical contact, 49% of study patients had received the first bolus of fibrinolytic compared with only 5% of controls (p < 0.0001). In-hospital mortality was 4.7%. Intracranial hemorrhage occurred in 1.0%. CONCLUSIONS Prehospital administration of rPA is a feasible approach to accelerating reperfusion in patients with STEMI. Valuable time savings can be achieved in the setting of contemporary transport and door-to-drug times and may translate into an improvement in clinical outcomes.

THE FAILED INTUBATION ATTEMPT IN THE EMERGENCY DEPARTMENT: ANALYSIS OF PREVALENCE, RESCUE TECHNIQUES, AND PERSONNEL

The aims of this study were: To describe the prevalence of Emergency Department (ED) airway management failures requiring rescue maneuvers, to describe successful rescue methods used when the primary method chosen is unsuccessful, and to characterize the roles of emergency physicians and other specialists in rescue airway management. A prospective observational study was conducted of ED airway management in 30 hospitals in the USA, Canada, and Singapore participating in the National Emergency Airway Registry (NEAR) database project. Patients were entered in the study if they underwent ED airway management, the first method chosen was not successful in achieving intubation, and a rescue technique was required. Data were collected on a structured data form for entry into a relational database with subsequent search for subjects fulfilling inclusion and exclusion criteria. Descriptive statistics were used for analysis of these data. There were 7,712 patients identified who underwent emergency intubation during the study period from January 1998 to February 2001. A total of 207 (2.7%) patient intubations met the inclusion criteria. Of these, 102 (49%) patients underwent rescue rapid sequence intubation (RSI). RSI was used after failure of oral intubation with sedation alone (n = 29), oral intubation without medications (n = 37), or blind nasotracheal intubation (n = 36). Forty-three (21%) patients underwent rescue cricothyrotomy after failure of RSI (n = 26) or other intubation methods (n = 17). Seventy-nine percent of rescue RSIs and 53% of rescue surgical airways were performed by emergency physicians. In conclusion, a total of 2.7% of emergency intubations required rescue. RSI is the most commonly used first line technique for ED airway management and is also the principal back-up technique when other oral or nasal intubation methods fail. Emergency physicians manage the majority of ED intubations, including those requiring rescue techniques.

Rapid sequence intubation for pediatric emergency airway management.

Objectives To characterize current practice with respect to pediatric emergency airway management using a multicenter data set. Methods A multicenter collaboration was undertaken to gather data prospectively regarding emergency intubation. Analysis of data on adult emergency department (ED) intubations clearly demonstrated that rapid sequence intubation (RSI) was the method used most often. We then conducted an observational study of the prospectively collected database of pediatric ED intubations (EDIs) using the National Emergency Airway Registry Phase One data, gathered in 11 participating EDs over a 16-month time period. A data form completed at the time of EDI enabled analysis of patients’ ages, weights, and indications for EDI; personnel; methods employed to facilitate EDI; success rates; and adverse events. Data forms were analyzed regarding the methods of intubation employed, and frequencies, success rates, and adverse event rates among various intubation modalities were compared. Results Of 1288 EDIs, there were 156 documented pediatric patients. Initial intubation attempts were all oral, including rapid sequence intubation in 81%, without medications (NOM) in 13%, and sedation without neuromuscular blockade (SED) in 6%. Older children and trauma patients were more likely to be intubated with RSI compared to younger children and patients presenting with medical illnesses. Intubation using RSI was more successful on the first attempt (78%) compared with either NOM (47%, P < 0.01) or SED (44%, P < 0.05), though this finding is likely explainable by the age differences among groups. Intubation was successfully performed by the initial intubator in 85% of RSI, 75% of NOM, and 89% of SED attempts (P = NS for both comparisons vs RSI). Overall, successful intubation occurred in 99% of RSI and 97% of non-RSI intubation attempts (P = NS). Only one of 156 patients required surgical airway management. True complications occurred in 1%, 5%, and 0% of RSI, NOM, and SED attempts, respectively (P = NS for both comparisons vs RSI). The majority of initial intubation attempts were by emergency medicine residents (59%), pediatric emergency medicine fellows (17%), and pediatrics residents (10%). These groups were 77%, 77%, and 50% successful, respectively, on the first laryngoscopy attempt, and 89%, 89%, and 69% successful overall. Conclusions A large, prospective, multicenter observational study of pediatric EDIs was conducted at university-affiliated EDs. RSI is the method of choice for the majority of pediatric emergency intubations; it is associated with a high success rate and a low rate of serious adverse events. Pediatric intubation as practiced in academic EDs, with most initial attempts by emergency and pediatrics residents and fellows under attending physician supervision, is safe and highly successful.

EMERGENCY AIRWAY MANAGEMENT: A MULTI-CENTER REPORT OF 8937 EMERGENCY DEPARTMENT INTUBATIONS

OBJECTIVE Emergency department (ED) intubation personnel and practices have changed dramatically in recent decades, but have been described only in single-center studies. We sought to better describe ED intubations by using a multi-center registry. METHODS We established a multi-center registry and initiated surveillance of a longitudinal, prospective convenience sample of intubations at 31 EDs. Clinicians filled out a data form after each intubation. Our main outcome measures were descriptive. We characterized indications, methods, medications, success rates, intubator characteristics, and associated event rates. We report proportions with 95% confidence intervals and chi-squared testing; p-values < 0.05 were considered significant. RESULTS There were 8937 encounters recorded from September 1997 to June 2002. The intubation was performed for medical emergencies in 5951 encounters (67%) and for trauma in 2337 (26%); 649 (7%) did not have a recorded mechanism or indication. Rapid sequence intubation was the initial method chosen in 6138 of 8937 intubations (69%) and in 84% of encounters that involved any intubation medication. The first method chosen was successful in 95%, and intubation was ultimately successful in 99%. Emergency physicians performed 87% of intubations and anesthesiologists 3%. Several other specialties comprised the remaining 10%. One or more associated events were reported in 779 (9%) encounters, with an average of 12 per 100 encounters. No medication errors were reported in 6138 rapid sequence intubations. Surgical airways were performed in 0.84% of all cases and 1.7% of trauma cases. CONCLUSION Emergency physicians perform the vast majority of ED intubations. ED intubation is performed more commonly for medical than traumatic indications. Rapid sequence intubation is the most common method of ED intubation.

A critical pathway for management of patients with acute chest pain who are at low risk for myocardial ischemia : Recommendations and potential impact

Acute chest pain is a common and costly problem [1, 2]. Various strategies have been evaluated to increase the efficiency of care for persons with acute chest pain, including reducing the number of inappropriate admissions, expediting transfer from intensive care units to intermediate-care units, or disseminating practice guidelines [1, 3-6]. Such interventions have achieved only modest success [5]. Many institutions are developing innovative strategies to address this problem [7, 8], including immediate exercise treadmill testing [9, 10], early noninvasive imaging [11, 12], use of new markers for myocardial injury [13], and creation of emergency departments for chest pain [6, 14, 15]. Although some of these strategies have been evaluated [6], few data describe the expected or actual effects of most strategies on clinical outcomes or resource use. Nevertheless, short observation protocols for patients with chest pain are being implemented throughout the United States [14, 15]. Previous studies [16-18] addressed whether a patient who presents to an emergency department has unstable angina or acute myocardial infarction. An emerging paradigm instead asks whether it is safe to discharge the patient or whether it is safe for the patient to undergo an exercise treadmill test. This paradigm focuses attention on the safety of the management strategy rather than on the diagnosis because diagnosis often cannot be conclusively determined in the time frame available [19, 20]. We developed a comprehensive, evidence-based approach to management of patients with acute chest pain in the emergency department. We used published investigations to define the strategy and resolved differences or gaps in the literature by consensus of local experts. Quality management techniques were incorporated by using critical pathways to reduce variation in patient care [21-23]. Critical pathways define and manage the timing and sequence of the rate-limiting steps in the process of providing health care [21]. Management of this process includes simultaneously monitoring and giving feedback to providers of information about achievement of expected and unexpected patient outcomes. Health care providers can then adjust patient management to prevent or modify unexpected outcomes. Critical pathways are distinct from clinical guidelines and algorithms [21]. Clinical guidelines define the appropriateness of care [21], and clinical algorithms define the step-by-step procedure for providing care, usually with conditional logic (if-then statements) [22]. Neither guidelines nor algorithms use simultaneous management of the process of care delivery to monitor compliance with recommended practice and identify opportunities for improvement. The specific goals of our critical pathway were to reduce admission rates and total days of hospitalization among patients who were at low risk for complications of ischemic disease and to limit adverse outcomes. To address these goals, we developed an explicit sequence of care and recommended the daily availability of early exercise treadmill testing in low-risk patients. We retrospectively applied the criteria of the critical pathway to data from a large cohort of patients with acute chest pain to assess the potential effects of implementation of the pathway on resource use and adverse outcomes. Methods The Critical Pathway Development We developed the critical pathway on the basis of scientific evidence and the experience of local opinion leaders and physician-investigators with long-standing interest in the topic. Relevant articles from the medical literature were identified by doing a MEDLINE search for English-language articles from 1990 to 1995 using the keywords chest pain, unstable angina, and myocardial infarction combined with randomized, controlled trial (PT) and cohort study. All identified papers were reviewed for relevance. Study quality was not explicitly evaluated because existing quality scales either have not been validated [24] or do not consider the value of Bayesian analyses [25]. Relevant articles were supplemented with a national clinical practice guideline for management of unstable angina [26]. Opinion leaders included staff emergency department physicians, staff cardiologists, and a cardiologist affiliated with a large health maintenance organization. An informal nominal group process was used to reach consensus [27]. The process consisted of a series of meetings and draft documents. Team members contributed recommendations based on the medical literature, and group discussion clarified and evaluated each recommendation. Team members independently reviewed the documents between meetings to comment on the work in progress. Consensus was achieved by unanimity. Content The flow of the critical pathway is shown in Figure 1. The pathway consisted of flowsheets with instructions and preprinted orders to facilitate use. Instructions provided suggestions to the end-user (usually an emergency department physician) about what information may facilitate decision making. The preprinted orders were designed to be selected by the physician in response to the instructions. Figure 1. Critical pathway for management of patients with acute chest pain who are at low risk for myocardial ischemia. Variance tracking was incorporated into the critical pathway to monitor the length of time that patients were present in the emergency department and the disposition and clinical outcomes of patients enrolled in the pathway [28, 29]. Time goals were suggested for the performance of key elements of the care process. Failure to meet these performance standards or occurrence of other explicit events were considered key variances, which may be reviewed later in aggregate to facilitate improvement of quality of care. We recommended recording the time interval between arrival in the emergency department and completion of the following tasks: 1) obtaining an electrocardiogram, 2) deciding to perform exercise treadmill testing, 3) obtaining the results of exercise treadmill testing, and 4) deciding to admit or discharge the patient. Eligibility Four clinical categories of patients were ineligible for enrollment in the critical pathway: patients with ongoing chest pain, patients with congestive heart failure present at initial clinical examination, patients with ischemia or injury present on the initial electrocardiogram (defined as ST-segment elevation, ST-segment depression, or T-wave inversion suggestive of ischemia or infarction and not known to be old), and patients judged by physicians to be at sufficiently low risk for myocardial ischemia to be discharged. At Brigham and Womens Hospital, Boston, Massachusetts, patients with active ischemia or infarction are treated by following other protocols [30]. Patients who clearly do not have ischemic chest pain are considered for direct discharge from the emergency department, as recommended by a national consensus panel [26]. Patients with left bundle-branch block and other electrocardiographic changes who might not be candidates for exercise electrocardiography were not explicitly excluded from eligibility for the pathway; patients could undergo alternative tests, such as exercise echocardiography or nuclear medicine studies, assuming that these technologies were available. Data Clinical, demographic, and outcome data were previously collected for a prospective cohort of consenting patients 30 years of age or older from the ongoing Chest Pain Study at Brigham and Womens Hospital [5, 31, 32]. These patients presented to the emergency department with chest pain and had no history of trauma or abnormal radiologic findings between 2 July 1990 and 18 February 1994. Inclusion criteria, definition of outcomes, and verification of outcomes for that cohort study are summarized below [5, 31, 32]. Clinical data were recorded by the emergency department physician at the time of presentation or by a research nurse before he or she had any knowledge of the patients outcome. These data were recorded on a standardized form that was part of the permanent medical record. A study nurse reviewed the charts of all admitted patients to determine subsequent outcome. Reviewers who were blinded to baseline clinical data classified patients into three categories on the basis of their final discharge diagnoses [5, 33]: acute myocardial infarction, unstable angina, or other. Acute myocardial infarction was diagnosed in admitted or discharged patients on the basis of characteristic evolution of serum enzyme levels, electrocardiographic changes, or sudden unexpected death within 72 hours of presentation [16]. Acute myocardial infarction was also diagnosed in 1) patients who did not meet these criteria but received acute reperfusion therapy with intravenous thrombolytic agents or primary percutaneous angioplasty and 2) patients who had new ST-segment elevation that evolved over the next day and had total occlusion of the infarction-related artery, an echocardiographic wall-motion abnormality that corresponded to the acute electrocardiographic changes, or an elevated total creatine kinase level and a creatine kinase-MB isoenzyme level greater than 2.5% of the total creatine kinase level, with characteristic evolution. Unstable angina was diagnosed if the original chest pain that led the patient to present to the emergency department was described by the patient as similar to or worse than previous symptoms of angina or myocardial infarction or if unstable angina was diagnosed by the senior clinician associated with the case. Other cardiac diagnoses, such as congestive heart failure or arrhythmias, and noncardiac diagnoses were made by the senior clinician involved with the case. Life-threatening complications were defined as nonfatal ventricular fibrillation, new type II second-degree atrioventricular block, new complete heart block, new atrioventricular dissociation, pulmonary edema, infarction extension, c

Rapid-sequence intubation in head trauma

Elevated intracranial pressure commonly is associated with severe head injury. Emergency airway management technique in the patient who has sustained severe head injury must optimize conditions for intubation, minimize the adverse effects of intubation, and permit rapid and effective management of the elevated intracranial pressure. Disturbances in autoregulation make the injured brain particularly susceptible to the adverse effects of alterations of systemic blood pressure. Airway manipulation without adequate pharmacologic support can cause precipitous changes in systemic hemodynamic parameters. This article reviews the physiologic and pathologic relationship among airway management, systemic hemodynamic parameters, and intracranial pressure. Specific recommendations for the use of neuromuscular blocking agents, anesthetic induction agents, and adjunctive medications are provided.

Clinical Correlates and Prognostic Significance of Early Negative Exercise Tolerance Test in Patients With Acute Chest Pain Seen in the Hospital Emergency Department

An exercise tolerance test (ETT) is often performed to identify patients for early discharge after observation for acute chest pain, but the safety of this strategy is unproven. We prospectively studied 276 low-risk patients who underwent an ETT within 48 hours after presentation to the emergency department with acute chest pain. The ETT was considered negative if subjects achieved at least stage I of the Bruce protocol and the electrocardiogram showed no evidence of ischemia. There were no complications associated with ETT performance. The ETT was negative in 195 patients (71%); there was no identifiable subsets of patients at very low probability of an abnormal test. During the 6-month follow-up, patients with a negative ETT had fewer additional visits to the emergency department (17% vs 21%, respectively; p < 0.05) and fewer readmissions to the hospital (12% vs 17%; p < 0.01) than those with positive or inconclusive ETTs. No patient with a negative ETT died and only 4 patients with a negative ETT experienced a major cardiac event (myocardial infarction, coronary angioplasty, or bypass) within 6 months. Among these 4 patients, only 1 had an event within 4 months. In conclusion, our results suggest that ETT can be safely used to identify patients at low risk of subsequent events. Patients without a clearly negative test are at increased risk for readmission and cardiac events, and should be reevaluated either during the same admission or shortly after discharge.

Time as an Adjunctive Agent to Thrombolytic Therapy.

Thrombolytic therapy has dramatically reduced mortality following acute myocardial infarction (MI) with the major effect coming fromearly achievement of infarct-related artery patency. A major factor in achieving rapid reperfusion is early treatment with thrombolytic therapy. Recent trials have shown that mortality can be reduced if time to treatment is shortened: In the Thrombolysis in Myocardial Infarction (TIMI) 2 trial, for each hour earlier that thrombolytic therapy was started, approximately 10 lives were saved per 1000 patients treated. Thus, one must considertime as an adjunctive agent to thrombolytic therapy. There are four components of the time delay between the onset of MI and achievement of reperfusion: (1) patient delays in seeking medical attention; (2) transport delays; (3) the so-called door to needle time, the interval between the patients arrival at the medical facility and the initiation of thrombolytic therapy; and (4) thrombolytic reperfusion time, the time between the administration of thrombolytic therapy and the achievement of reperfusion. Efforts to reduce each of these components will lead to additive benefits in improving time to reperfusion and survival of patients with acute MI.

Effect of Just-in-time Simulation Training on Tracheal Intubation Procedure Safety in the Pediatric Intensive Care Unit

Background:Tracheal intubation-associated events (TIAEs) are common (20%) and life threatening (4%) in pediatric intensive care units. Physician trainees are required to learn tracheal intubation during intensive care unit rotations. The authors hypothesized that “just-in-time” simulation-based intubation refresher training would improve resident participation, success, and decrease TIAEs. Methods:For 14 months, one of two on-call residents, nurses, and respiratory therapists received 20-min multidisciplinary simulation-based tracheal intubation training and 10-min resident skill refresher training at the beginning of their on-call period in addition to routine residency education. The rate of first attempt and overall success between refresher-trained and concurrent non–refresher-trained residents (controls) during the intervention phase was compared. The incidence of TIAEs between preintervention and intervention phase was also compared. Results:Four hundred one consecutive primary orotracheal intubations were evaluated: 220 preintervention and 181 intervention. During intervention phase, neither first-attempt success nor overall success rate differed between refresher-trained residents versus concurrent non–refresher-trained residents: 20 of 40 (50%) versus 15 of 24 (62.5%), P = 0.44 and 23 of 40 (57.5%) versus 18 of 24 (75.0%), P = 0.19, respectively. The residents first attempt and overall success rate did not differ between preintervention and intervention phases. The incidence of TIAE during preintervention and intervention phases was similar: 22.0% preintervention versus 19.9% intervention, P = 0.62, whereas resident participation increased from 20.9% preintervention to 35.4% intervention, P = 0.002. Resident participation continued to be associated with TIAE even after adjusting for the phase and difficult airway condition: odds ratio 2.22 (95% CI 1.28–3.87, P = 0.005). Conclusions:Brief just-in-time multidisciplinary simulation-based intubation refresher training did not improve the residents first attempt or overall tracheal intubation success.