SAEM 2003: Reviews of the Latest Research in Emergency Medicine

The following are brief summaries of nine abstracts presented at the Society for Academic Emergency Medicine (SAEM) 2003 Annual Meeting in Boston. Editorial board members who attended selected these topics because of their interesting content and importance to the field of emergency medicine research. Because these are abstracts and not peer-reviewed publications, results and conclusions should be considered preliminary. — The Editor

Antibiotic Use Not Supported for Dental Pain Without Infection

Source: Runyon MS, et al. The utility of anti-microbial therapy for dental pain without overt infection. Acad Emerg Med 2003;10:435.

In this study, the authors conducted a prospective, randomized, double-blind study on the impact of antibiotics in the treatment of dental pain in which there is no overt evidence of infection. A convenience sample of 195 patients who presented to the emergency department (ED) with dental pain were randomized to either penicillin or placebo. Both groups received standardized pain treatment with anti-inflammatory and opioid medications. Patients were excluded from the study if they had fever, oral swelling, trismus, pregnancy, immunocompromise, valvular heart disease, or trauma. There was no difference in the two groups in terms of baseline characteristics or pain scores at the time of enrollment. Of the total, 125 patients followed up at 5-7 days and underwent a structured examination for signs of infection, including fever, oral swelling, trismus, or purulent drainage. In addition, another six patients were identified by return to the ED or dental clinic for worsening pain.

Overall, there was no difference between the two groups in infection rate at follow-up (9.5% in the penicillin group vs 10.3% in the placebo group). There also was no difference between the groups in terms of actual pain scores (visual analogue scale) at follow-up as well as improvement in pain scores. The authors conclude that their study does not support the routine use of antibiotics in patients presenting to the ED with dental pain without overt evidence of infection. — Reviewed by Theodore C. Chan, MD, FACEP. Dr. Chan, Associate Clinical Professor of Medicine, Emergency Medicine, University of California, San Diego, is on the editorial board of Emergency Medicine Alert.

TIA a High-Risk Sentinel Event for Future Morbidity and Mortality

Source: Panagos PD, et al. Short-term prognosis after emergency department diagnosis and evaluation of transient ischemic attack (TIA). Acad Emerg Med 2003;10:432.

In this study, the authors performed a population-based, retrospective study of patients who were diagnosed with new-onset transient ischemic attack (TIA) in the emergency department (ED). The investigators sought to determine the short-term risk of recurrent TIA, stroke, and death during the six months following the index diagnosis. The study was conducted during a one-year period in a midwestern region of approximately 1.3 million persons. Utilizing a number of methods to identify patients, including discharge codes, ED admission logs, and coroner records, investigators identified 790 patients diagnosed with TIA in the ED. All cases underwent retrospective chart review conducted by study nurses and followed by a physician review. The investigators report the rates of stroke following the ED diagnosis of TIA was 9.2% at 30 days, 13.3% at 90 days, and 16.7% at six months. The six-month rate for recurrent TIA was 9.3%, and for death was 14.9%.

The authors conclude that the initial presentation of TIA to the ED is a high-risk sentinel event, as these patients are at significantly increased risk for subsequent recurrent TIA, stroke, and death during the immediate short-term, six-month follow-up period. — Reviewed by Theodore C. Chan, MD, FACEP

Large Needles: More Headaches after LP?

Source: Seupaul RA, et al. Prevalence of post-dural puncture headache after ED performed lumbar puncture. Acad Emerg Med 2003;10:543.

In this study, the investigators conducted a multicenter, observational, prospective study of the incidence of post-dural puncture headache following lumbar puncture (LP) performed in the emergency department (ED). Patients presenting at one of two large urban EDs and requiring lumbar puncture were enrolled consecutively in the study. Follow-up was conducted by telephone interview after the ED visit to determine the incidence of complications as a result of the procedure. Post-dural puncture headache was defined as any headache that worsened with positional change and improved with supine position. All LPs were performed with either a 20- or 22-gauge needle.

Overall, 72 patients were enrolled from the two ED sites, with an overall prevalence of post-dural headache of 17.9%. This rate is higher than that generally reported in the anesthesia literature. In addition, post-dural headache rates were significantly higher in patients who had LP performed with the larger gauge needle (20g) than the smaller gauge needle (22g) (37% vs 10%). Absolute risk reduction was 0.27 with use of the smaller needle. The investigators conclude that use of the larger gauge needle for LPs resulted in significantly higher rates of post-dural headache following lumbar puncture performed in the ED. — Reviewed by Theodore C. Chan, MD, FACEP

Which Historical Factors Predict SAH?

Source: Perry JJ, et al. The value of history in the diagnosis of subarachnoid hemorrhage for emergency department patients with acute headache. Acad Emerg Med 2003;10:553.

The authors of this prospective study attempted to determine the value of specific historical factors in predicting the presence of subarachnoid hemorrhage (SAH) in emergency department (ED) patients with headache. Patients were enrolled if they complained of acute headache that peaked within one hour, had no neurologic deficit, and had no history of similar headache, trauma, prior SAH, or brain neoplasm. SAH was defined as a positive computed tomography result, cerebrospinal fluid (CSF) xanthochromia, or red cells in the last tube of CSF with positive cerebral angiography. The authors do not state the overall rate of SAH in the 589 enrolled patients, but it appears to be at least 5%. Six percent of patients who obtained complete relief from anti-migraine therapy were found to have an SAH. Significant adjusted odds ratios for the presence of SAH were associated with age older than 50 years (adjusted OR 7.8, CI not provided), neck pain (adjusted OR 5.4), and vomiting (adjusted OR 2.7). The authors conclude that these historical factors should be sought in patients complaining of acute headache, and that relief of symptoms with therapy does not exclude the presence of SAH. — Reviewed by David J. Karras, MD, FACEP, FAAEM. Dr. Karras, Associate Professor of Emergency Medicine, Department of Emergency Medicine Temple University School of Medicine, Director of Emergency Medicine Research, Temple University Hospital, Philadelphia, PA, is on the editorial board of Emergency Medicine Alert.

Adding ALS May Not Improve on Rapid Defibrillation in Out-of-Hospital Cardiac Arrest

Source: Stiell IG, et al. OPALS Study Phase III: What is the impact of advanced life support on out-of-hospital cardiac arrest? Acad Emerg Med 2003;10:423.

This phase of the Ontario Prehospital Advanced Life Support (OPALS) Study examined the benefit of adding an advanced life support (ALS) program to a basic life support (BLS) emergency medical system that already employs defibrillation. The trial compared outcomes of cardiac arrest victims before and after training of paramedics to meet ALS standards. The study was conducted in 17 Ontario communities and enrolled 1391 patients in the BLS phase and 4246 in the ALS phase. Patients in the two groups were well-matched in terms of initial cardiac rhythm and time to initiation of life support. While patients in the ALS phase had higher rates of hospital admission than those in the BLS phase (15% vs 11%), survival was 5% in both groups. The authors conclude that the addition of prehospital ALS does not improve survival when an effective BLS/rapid defibrillation program is already in place. This study reinforces previous findings that early defibrillation is the most effective—indeed, perhaps the only effective—therapeutic modality available for cardiac arrest victims. — Reviewed by David J. Karras, MD, FACEP, FAAEM

Antibiotic Resistance Difficult to Predict in UTI

Source: Norton R, et al. Inability to predict antimicrobial resistance of UTI pathogens in ED patients. Acad Emerg Med 2003;10:436.

The authors of this retrospective study attempted to develop a clinical decision rule to predict resistance to trimethoprim-sulfamethoxazole (TMP/SMX) in emergency department (ED) patients with urinary tract infections (UTI). Records of adult female patients seen in a single ED during a 26-month period were reviewed and 18 predictor variables were collected. Using classification and regression tree (CART) analysis, the authors attempted to predict TMP/SMX resistance among those patients found to have culture-confirmed UTI. Twenty percent of 512 cultures were TMP/SMX-resistant; this rate did not vary during the 26-month study period. The authors found no useful predictors of TMP-SMX resistance, and concluded that ciprofloxacin is appropriate empiric UTI therapy in settings with high rates of TMP-SMX resistance. These results are similar to those of studies performed in outpatient settings, and emphasize the need to be aware of local antibiotic resistance rates when selecting antimicrobial therapy. — Reviewed by David J. Karras, MD, FACEP, FAAEM

Reverse Trendelenburg Position May Increase Success in Femoral Vein Catheterization

Source: Stone MB, Price DD, Anderson BS. The effect of the reverse Trendelenburg position on the cross-sectional area of the femoral vein. Acad Emerg Med 2003;10:563.

Previous studies have demonstrated that the Trendelenburg position increases the cross-sectional area of the internal jugular vein. In this study, the authors attempted to demonstrate the effect of the Reverse Trendelenburg (RT) position on the cross-sectional area of the femoral vein. The subjects were 52 volunteers with no history of deep venous thrombosis or vascular surgery in the lower limbs. Using a 7.5 MHz two-dimensional linear ultrasound transducer, the cross-sectional area of the left and right femoral veins of the subjects was measured in the supine and 15° RT position. The mean cross-sectional area of the femoral veins with the subjects supine was 0.85 cm2, and the mean cross-sectional area of the femoral veins with the subjects in the RT position was 1.22 cm2. The increase in cross-sectional area of the femoral vein was statistically significant (p < 0.001), with a mean increase of 55% ± 9.1%. No differences were found between right and left femoral vein dimensions (p = 0.9). The authors concluded that the cross-sectional area of the femoral vein is significantly increased by using the RT position. They state that this maneuver may increase the success rate of femoral vein catheterization. — Reviewed by Jacob W. Ufberg, MD. Dr. Ufberg, Assistant Professor of Emergency Medicine, Assistant Residency Director, Department of Emergency Medicine, Temple University School of Medicine, Philadelphia, PA, is on the editorial board of Emergency Medicine Alert.

Ultrasound Aids in Difficult Peripheral IV Catheter Placement

Source: Costantino TG, et al. Success rate of peripheral IV catheter insertion by emergency physicians using ultrasound. Acad Emerg Med 2003;10:487.

The purpose of this study was to measure the success rate of emergency physicians (EPs) using ultrasound to guide peripheral intravenous catheter (PIVC) placement among patients who could not be successfully cannulated by emergency department (ED) nurses. Subjects included a convenience sample of patients presenting to an urban ED during a six-month period who could not have a PIVC placed by any available ED nurse or paramedic. Unstable patients and patients requiring central venous access, as determined by the treating physician, were excluded. Study investigators then used ultrasound guidance with a 7.5-10 MHz linear probe to attempt PIVC placement. Fifty-one patients were enrolled in the study, with investigators able to place PIVCs in 46 of 51 patients (92%). Of the patients in whom a PIVC was placed, 43 of 46 were placed on the first attempt. The majority of PIVCs were placed in the basilic, cephalic, antecubital, or forearm veins, with four (8%) placed in the brachial vein. One case (2%) of brachial artery puncture was the only reported complication. The average time to successful PIVC placement was 2.5 minutes. The authors conclude that EPs can successfully place PIVCs using ultrasound when ED nurses are unable to do so by standard techniques. — Reviewed by Jacob W. Ufberg, MD

Femoral Nerve Block More Effective Analgesia for Isolated Femur Fracture

Source: Levine J, et al. A randomized, controlled trial comparing femoral nerve block to intravenous morphine in isolated femur fractures. Acad Emerg Med 2003;10:469.

In this study, the authors compared the analgesic efficacy of intravenous (IV) morphine and femoral nerve block (FNB) in patients with isolated femur fractures. Patients with isolated mid-shaft femur fractures who consented to inclusion were randomized to receive either0.1 mg/kg of IV morphine sulfate or FNB with 20 mL of 0.5% bupivacaine. Subjects completed a visual analog pain scale (VAS) prior to the study intervention, and again one hour after the intervention. Adverse effects of each study intervention were recorded, along with the need for rescue analgesia. All participating physicians were trained and certified in the administration of FNB.

Sixteen patients were enrolled in the study, 10 in the FNB group, and six in the morphine sulfate group. The change in VAS at one hour was significantly greater in the FNB group (median VAS change in FNB group vs morphine group 56 mm vs 11 mm, p = 0.004). The need for rescue medication was significantly greater in the morphine group (RR 8.3, 95% CI 1.2-55.3). There were no adverse effects reported in either group. The authors conclude that FNB results in significantly greater analgesia than standard doses of morphine plus additional opiate analgesia for isolated femur fractures, and that patients who receive FNB require less rescue analgesics than those who receive morphine. — Reviewed by Jacob W. Ufberg, MD