M. Andrew Levitt

Accuracy of emergency physician assessment of left ventricular ejection fraction and central venous pressure using echocardiography

OBJECTIVESnEmergency department (ED) bedside echocardiography may offer useful information on cardiac function and volume status. The authors evaluated the accuracy of emergency physician (EP) performance of echocardiography in the assessment of left ventricular ejection fraction (LVEF) and central venous pressure (CVP).nnnMETHODSnThe authors conducted a cross-sectional observational study at an urban teaching ED, involving a convenience sample of patients presenting to the ED between September 2000 and February 2001. Level III-credentialed EP sonographers who had undergone a three-hour training session in limited echocardiography, focusing on LVEF and CVP measurement, performed echocardiograms. Vital signs and indication for echocardiography were documented on a study data sheet. LVEF was rated as poor (<30%), moderate (30%-55%), or normal (>55%) and an absolute percentage. Central venous pressure categories included low (<5 cm), moderate (5-10 cm), and high (>10 cm). Formal echocardiograms were obtained within a four-hour window on all patients and interpreted by a staff cardiologist. Correlation analysis was performed using the kappa correlation coefficient for LVEF and CVP categories and a Pearson correlation coefficient for LVEF measurement.nnnRESULTSnA total of 115 patients were assessed for LVEF, and 94 patients had complete information for CVP. Indications for echocardiography included chest pain (45.1%), congestive heart failure (38.1%), dyspnea (5.7%), and endocarditis (10.6%). Results showed a LVEF correlation of r(2) = 0.712 with 86.1% overall agreement. Subgroup analysis revealed the highest agreement (92.3%) between EP and formal echocardiograms within the normal LVEF category, followed by 70.4% agreement in the poor LVEF category and 47.8% in the moderate LVEF category. Central venous pressure measurements resulted in 70.2% overall raw agreement between EP and formal echocardiograms. Subgroup analysis revealed the highest agreement (83.3%) within the high CVP category followed by 66.6% in the moderate and 20% in the low categories.nnnCONCLUSIONSnExperienced EP sonographers with a small amount of focused additional training in limited bedside echocardiography can assess LVEF accurately in the ED.

Real-Time Ultrasound–Guided Femoral Vein Catheterization During Cardiopulmonary Resuscitation

STUDY OBJECTIVEnTo compare the use of real-time-ultrasound guidance with the standard landmark-oriented approach for obtaining femoral vein catheterization in patients requiring intravenous access during CPR.nnnMETHODSnProspective, randomized, paired subject-controlled clinical trial in the setting of an urban teaching county hospital emergency department. The study comprised a convenience sample of 20 patients presenting with apnea and pulselessness in the ED. Each patient received bilateral femoral lines, one by ultrasound guidance and one by the landmark approach (control). Randomization determined which technique and which side would be attempted first. The following parameters were recorded: time to initial flash of blood, time to completion of catheterization, number of needle passes, and rate of arterial catheterization. CPR and Advanced Cardiac Life Support protocols were continued during both procedures.nnnRESULTSnReal-time ultrasound-guided catheterization had a higher success rate (90% versus 65%, P = .058), a lower number of needle passes (2.3 +/- 3 versus 5.0 +/- 5, P = .0057), and a lower rate of arterial catheterization (0% versus 20%, P = .025) than the standard landmark-oriented approach. Ultrasound was also slightly faster in time to blood flash and in time to catheterization. An incidental finding of interest was that real-time ultrasound demonstrated the presence of femoral vein pulsations during CPR.nnnCONCLUSIONnReal-time ultrasound-guided femoral vein catheterization was faster and produced a lower rate of inadvertent arterial catheterization and a higher rate of success during CPR than the standard landmark-oriented approach. Also, ultrasound demonstrated that palpable femoral pulsation during CPR is venous rather than arterial.

Randomized, Double-Blind, Placebo-Controlled Trial of Intravenous Ketamine in Acute Asthma

STUDY OBJECTIVEnTo evaluate the efficacy of IV ketamine in the management of acute, severe asthma.nnnMETHODSnThis prospective, randomized, double-blind, placebo-controlled clinical trial at an urban teaching hospital emergency department involved 53 consecutive patients aged 18 to 65 with a clinical diagnosis of acute asthmatic exacerbation and a peak expiratory flow of less than 40% of the predicted value after three albuterol nebulizer treatments. All patients received oxygen, continuous nebulized albuterol, and methylprednisolone sodium succinate (Solu-Medrol). Patients then received either ketamine hydrochloride in a bolus of .2 mg/kg followed by IV infusion of .5 mg/kg per hour for 3 hours or a placebo bolus and infusion for 3 hours. Because of the occurrence of dysphoric reactions, the bolus dose was lowered to .1 mg/kg after the first 9 patients; the infusion dose was kept the same.nnnRESULTSnThe first nine patients were eliminated from analysis. Repeated ANOVA testing on the remaining 44 patients determined significant improvements over time within each treatment group in peak flow (F=3.637, P=.004). Borg score (F=22.959, P=.001), respiratory rate (F=8.11, P=.0001). and 1-second forced expiratory volume (F=9.076, P=.001). However, no difference could be detected over time between treatment groups (power, 80%). Patients receiving ketamine gave the treatment a rating of 4.3 on a scale of 1 to 5, whereas those receiving placebo scored their treatment 3.7 (P=.0285). The hospital admission rate was not different between treatment groups (P=.1088).nnnCONCLUSIONnIV ketamine at a dose low enough to avoid dysphoric reactions demonstrated no increased bronchodilatory effect compared with standard therapy in treating exacerbations of asthma in the ED. Although there was a slight increase in satisfaction in the ketamine group, no clinical benefit in terms of hospital admission rate was noted.

Does the presence of ultrasound really affect computed tomographic scan use? A prospective randomized trial of ultrasound in trauma

OBJECTIVEnThere is a paucity of evidence demonstrating that emergency department (ED) ultrasound changes clinical practice in trauma patients. We hypothesized that the presence of ultrasound would affect clinical decision making as evidenced through abdominal computed tomographic (CT) scan use in blunt multiple trauma patients.nnnMETHODSnThis study used a prospective randomized format in an urban county ED with Level II trauma center status (ED census, 72,000 patients per year). Participants were patients with multiple blunt injuries meeting trauma center triage criteria. Patients were randomized to receive either abdominal ultrasound or no ultrasound (control) during initial ED resuscitation. The primary outcome variable was use of abdominal CT scan in patients with and without ultrasound.nnnRESULTSnTwo hundred eight patients were enrolled. The mean age was 40 +/- 18 years, and 62% were men. Mechanism of injury was motor vehicle crash, 56%; automobile versus pedestrian, 18%; motorcycle crash, 16%; falls, 10%; and other, 10%. One hundred four ultrasound and 104 control patients were analyzed. There were no apparent differences between ultrasound and control groups in demographics, injury type, or Injury Severity Score. Fifty-four of 104 (52%) of the control group received abdominal CT scans versus 37 of 104 (36%) abdominal CT scans for the ultrasound group; mean difference in proportions was 15.9 (p < 0.01; 95% confidence interval, 2.6-29.1).nnnCONCLUSIONnIn this trial, the routine use of abdominal ultrasound in the evaluation of patients with multiple blunt injuries resulted in significantly fewer abdominal CT scans being obtained. A larger trial is needed to more clearly define the clinical and financial impact of ultrasound in the management of blunt abdominal trauma.

Combined Cardiac Marker Approach With Adjunct Two-Dimensional Echocardiography to Diagnose Acute Myocardial Infarction in the Emergency Department

STUDY OBJECTIVEnTo evaluate a combined cardiac marker approach with adjunct two-dimensional echocardiography in diagnosing acute myocardial infarction (AMI) in the emergency department.nnnMETHODSnThis prospective, cohort study enrolled 190 patients aged 18 years and older who presented to the ED of a county teaching hospital and were admitted with chest pain suggestive of AMI. A standardized history and physical examination were performed. Serum sampling for myoglobin and creatine kinase-MB (CK-MB) was done at the time of presentation (time 0) and 3 hours later (time 3 hours). An echocardiographic study was obtained, and a left ventricular wall motion score was derived.nnnRESULTSnUsing World Health Organization criteria, 21 patients (11.2%) with AMI were identified. The serum markers were found to be clinically and statistically different between AMI and non-AMI groups at both time 0 and time 3 hours. Receiver operator characteristic curves were used to determine a positive myoglobin level at 88.7 ng/mL or higher at either time point, and a positive CK-MB level at 11.9 ng/mL or higher; these were used as the optimal cutoff values to predict AMI in the ED. Serum myoglobin was a more sensitive marker (90.5%) than CK-MB (81.0%). However, CK-MB was more specific (99.4%) than myoglobin (88.4%). A combination of both tests, which was rated positive if either test was positive, was a superior predictor overall, with a 100% capture rate of AMI patients and a 91.2% specificity. No significant difference in echocardiographic scores was appreciated in the AMI group compared with the non-AMI group (16.9 +/- 1.5 versus 15.3 +/- .5, respectively; P = .3252).nnnCONCLUSIONnSerum myoglobin shows greater sensitivity but is less specific than CK-MB in the early detection of AMI. Use of a combination of both rapid assays during a 3-hour time period in the ED appears to be superior to use of either enzyme assay alone. Two-dimensional echocardiography does not appear to be helpful in diagnosing AMI in the ED.

Abbreviated Educational Session Improves Cranial Computed Tomography Scan Interpretations by Emergency Physicians

STUDY OBJECTIVEnPreviously published research (phase I) demonstrated a concerning misinterpretation rate of cranial computed tomography (CT) scans by emergency physicians. This study (phase II) determined whether an abbreviated educational session would improve emergency physician interpretation skills of cranial CT scans.nnnMETHODSnParticipants in this prospective, interventional study in a county hospital ED were patients undergoing cranial CT scanning during ED evaluations and attending level emergency physicians. An abbreviated educational session on cranial CT interpretation skills was given to the same attending emergency physicians who participated in phase I. The educational session included basic CT interpretation skills and misinterpreted CT scans from phase I. We determined the postsession accuracy rate of the emergency physicians on 324 ED patient CT scans. The CT interpretation accuracy rates were then compared between phase I and phase II to determine the effectiveness of the educational session.nnnRESULTSnThe radiology/ED CT scan concordance rate improved from 61.3% (kappa = .22) to 88.6% (kappa = .70; P < .0001). Potentially clinically significant CT scan misinterpretations decreased from 24.1% to 4.0% (P < .0001). Most importantly, major missed findings on CT scans decreased from 11.4% to 2.8% (P < .0001). Continuous quality improvement monitoring found no instance of clinically significant patient mismanagement.nnnCONCLUSIONnWithin the limits of this study, we conclude that emergency physicians interpretation skills of cranial CT scans may be improved using a 1-hour educational session.