A prospective diffusion tensor imaging study in mild traumatic brain injury.

OBJECTIVES: Only a handful of studies have investigated the nature, functional significance, and course of white matter abnormalities associated with mild traumatic brain injury (mTBI) during the semi-acute stage of injury. The present study used diffusion tensor imaging (DTI) to investigate white matter integrity and compared the accuracy of traditional anatomic scans, neuropsychological testing, and DTI for objectively classifying mTBI patients from controls. METHODS: Twenty-two patients with semi-acute mTBI (mean = 12 days postinjury), 21 matched healthy controls, and a larger sample (n = 32) of healthy controls were studied with an extensive imaging and clinical battery. A subset of participants was examined longitudinally 3-5 months after their initial visit. RESULTS: mTBI patients did not differ from controls on clinical imaging scans or neuropsychological performance, although effect sizes were consistent with literature values. In contrast, mTBI patients demonstrated significantly greater fractional anisotropy as a result of reduced radial diffusivity in the corpus callosum and several left hemisphere tracts. DTI measures were more accurate than traditional clinical measures in classifying patients from controls. Longitudinal data provided preliminary evidence of partial normalization of DTI values in several white matter tracts. CONCLUSIONS: Current findings of white matter abnormalities suggest that cytotoxic edema may be present during the semi-acute phase of mild traumatic brain injury (mTBI). Initial mechanical damage to axons disrupts ionic homeostasis and the ratio of intracellular and extracellular water, primarily affecting diffusion perpendicular to axons. Diffusion tensor imaging measurement may have utility for objectively classifying mTBI, and may serve as a potential biomarker of recovery.

A new approach to teaching prehospital trauma care to paramedic students.

STUDY OBJECTIVE: A modification of the standard Department of Transportation student paramedic curriculum encouraging individualized patient assessment decreases inappropriate on-scene procedures (OSPs) and scene time, measured on simulated patients. METHODS: Scenario-based testing from 1991 through 1993 was videotaped for all students. A new trauma curriculum was introduced in 1992, individualizing patient assessment and prioritization of OSPs. Recorded OSPs included spinal immobilization, application of military antishock trousers, endotracheal intubation, cricothyrotomy, intravenous catheter insertion, and needle thoracostomy. Twenty videotaped random student performances of the 1991 class was compared with a similar sample of 20 from the 1993 class; scene times and the OSP numbers were measured. Two board-certified independent emergency physicians unfamiliar with the students or the new curriculum reviewed all 40 tests on a master videotape. Patient assessment appropriateness, scene time, OSPs, scenario difficulty, and number of inappropriate OSPs were evaluated using a linear analog scale. Data are presented as means with confidence intervals (CIs), analyzed by Student's t test and the Mann-Whitney 2-sample test. RESULTS: Scene time from 1991 to 1993 decreased overall with a mean of 4.3 minutes (95% CI 2.8 to 5.8 minutes), as did the number of OSPs: 3.1 versus 1.7 (mean difference, 1.45 OSPs per scenario; 95% CI.91 to 1.99). Physician reviewers noted improvements in the appropriateness of patient assessment, scene time, and OSPs from 1991 to 1993. There was no significant difference in scenario difficulty for 1991 compared with 1993. Inappropriate OSPs done on scene declined. Physician 1 indicated a mean of inappropriate procedures of 1.6 in 1991 versus.5 in 1993. Physician 2 indicated a mean of 1.4 in 1991 versus.3 in 1993. CONCLUSION: This new paramedic curriculum decreased on-scene time and inappropriate use of procedures in stabilizing the condition of patients with simulated critical trauma.

192IrCl acid skin burn: case report and review of the literature.

A worker was contaminated following a chemical explosion that splashed an HNO3 radioactive solution containing approximately 180 MBq (5 mCi) 192Ir onto the left side of his face. Initial efforts reduced the contamination at least fivefold. Removal of a patch of contaminated hair was necessary. Most of the contamination was fixed to the skin; only a small amount of contamination was absorbed.

The development of international emergency medicine: a role for U.S. emergency physicians and organizations. SAEM International Interest Group.

There is a rapidly growing interest in emergency medicine (EM) and emergency out-of-hospital care throughout the world. In most countries, the specialty of EM is either nonexistent or in an early stage of development. Many countries have recognized the need for, and value of, establishing a quality emergency health care system and are striving to create the specialty. These systems do not have to be high tech and expense but can focus on providing appropriate emergency training to physicians and other health care workers. Rather than repeatedly "reinventing the wheel" with the start of each new emergency care system, the preexisting knowledge base of EM can be shared with these countries. Since the United States has an advanced emergency health care system and the longest history of recognizing EM as a distinct medical specialty, lessons learned in the United States may benefit other countries. In order to provide appropriate advice to countries in the early phase of emergency health care development, careful assessment of national resources, governmental structure, population demographics, culture, and health care needs is necessary. This paper lists specific recommendations for EM organizations and physicians seeking to assist the development of the specialty of EM internationally.

Does a physician visual assessment change triage?

A prospective comparative trial was conducted to determine the effect of a physician's visual assessment of emergency patients on triage categorization and ability at triage to predict admission. The setting was a university, county, referral center and residency training site. Participants were a consecutive sample of emergency department patients presenting between the times of 0700 and 2300 hours for 5 weeks. All patients were assigned a triage category by an emergency nurse (RN) who saw the patient and by an emergency physician (EP) who had the option of performing a visual assessment. Triage categorization was compared for interobserver agreement (Kappa [kappa] statistic) and by ability to predict admission (MacNemar's test). A total of 3,949 patients was entered. The patients that physicians visually assessed were triaged by nurses as more ill (P < .001). For triage categories visualized by the EP compared with RN categorization, interobserver agreement was 59.8%, kappa = .21. For triage categories not visualized by EP compared with RN categorization, interobserver agreement was 67.9%, kappa = .45 (P < .001). Sensitivity of EPs to predict admission is as follows: all RN triage, 41.3; not seen by EP, 54.9; seen by EP, 69.3. Specificity is as follows: all RN triage, 93.7; not seen by EP, 88.5, seen by EP, 83.9. When physician visual assessment was done, agreement between physicians and nurses decreased by more than half. Physicians who included visual assessment in patient triage were less likely to agree with RN categorization. A visual assessment by the physician improved the sensitivity for predicting admission with an only small cost in specificity.

Triage: limitations in predicting need for emergent care and hospital admission.

STUDY OBJECTIVE: Little is known about the accuracy and reliability of current triage methods. We examined agreement among observers with regard to the need for ED care and the ability to predict at triage the need for admission to the hospital and compared these findings with admission rates after medical evaluation and management. METHODS: We used a crossover design in which each subject was subjected to nurse or computer-guided triage first, the other type of triage second, and physician triage last. Our null hypothesis: Triage methods will yield the same results. Our patients were a consecutive sample of patients at the ED of a university-affiliated county referral center. Critically ill patients were excluded. Triage categorization was examined for interobserver agreement (kappa-statistic) and prediction of admission (sensitivity, specificity, and predictive values). RESULTS: Of the 5,106 patients enrolled in the study, 289 (6.2%) were admitted. With regard to the agreement of triage categorizations, we found kappa-values of .452 and .185, respectively, for physician triage compared with nurse (SE +/- .012) and computer triage (SE +/- .012)(P = .001 for the difference between the kappa values). Sensitivity and specificity in predicting admission were 41.3 and 93.8, respectively, for nurses, 61.6 and 87.1, respectively, for physicians; and 68.2 and 73.6, respectively, for computer-aided triage. CONCLUSION: We found great variability among physicians, nurses, and a computer program with regard to triage decisions. Comparison of the three groups' triage decisions with actual data after medical evaluation and management showed that none of the three performed well in predicting which patients required admission. Until triage methods are standardized and validated, triage decisions should not be used to determine the timeliness of access to emergency care.

Cerumen occlusion lowers infrared tympanic membrane temperature measurement.

OBJECTIVE: To examine the effect that cerumen occlusion of the ear canal has on infrared tympanic membrane temperature measurement. METHODS: A prospective, randomized, single-blind human study was carried out in a university hospital observation unit. The subjects were a convenience sample of human volunteers ages 18 years or older who did not have cerumen occlusion or scarred tympanic membranes. A paraffin-coated human cerumen plug was placed in one randomly chosen ear, and after 20 minutes of equilibration the temperature of each ear was measured with an infrared thermometer. Analysis of the difference in mean temperature between the occluded and nonoccluded ears was by Student's paired t-test. RESULTS: Infrared tympanic membrane temperatures were measured in 43 subjects aged 21 to 58 years. The mean temperature of the occluded ear canal was 0.3 degrees C lower than that of the opposite ear canal (p = 0.0001, 95% CI 0.16-0.45 degrees C). CONCLUSION: Cerumen occlusion of the ear canal causes underestimation of body temperature measure by infrared tympanic membrane thermometry.

Magnetic resonance imaging in minor head injury.

STUDY OBJECTIVES: To investigate the role of cranial magnetic resonance (MR) imaging in evaluating patients discharged from the emergency department after minor head injury. DESIGN: A prospective blinded cohort study. SETTING: University hospital ED. TYPE OF PARTICIPANTS: Fifty-eight patients with minor head injury who were discharged from the ED with written head injury instructions. Patients admitted to the hospital were excluded. INTERVENTIONS: Ultra-low-field cranial MR scans were performed on patients within 24 hours of discharge. Scans were read blindly by two radiologists. MEASUREMENTS AND MAIN RESULTS: Fisher's exact test was used to compare symptoms in patients with abnormal and normal MR scans. There was no significant difference in symptoms between patients with abnormal and those with normal scans (P greater than .10). The proportion of abnormal MR scans was analyzed using the binomial distribution. Six of the 58 patients (10.3%) had traumatic intracranial abnormalities (proportion, 0.103; SD, 0.04; 95% CI, 0.04-0.21). Three had cortical contusions, and three had small subdural hematomas. Two of the six patients with abnormal MR scans, both with small subdural hematomas, had normal computed tomography scans. CONCLUSION: Ten percent of patients discharged from the ED after minor head injury had abnormal ultra-low-field cranial MR scans. Additional research is needed to establish the clinical importance of this unexpected observation.

Under-reporting of contaminated needlestick injuries in emergency health care workers.

STUDY HYPOTHESIS: There is considerable under-reporting of contaminated occupational needlestick and other sharp object injuries among emergency health care workers. POPULATION: A convenience sample of emergency physicians, emergency nurses, and emergency medical technicians (EMTs). METHODS: A survey instrument eliciting demographic and work-related factors was developed and administered; survey items included age, sex, occupation, years in occupation, number of procedures performed per week, number of contaminated needlestick (and other "sharps") injuries recalled, and number of these injuries formally reported during the previous five years. Nonsegmented visual analog scales were used to assess eight attitudes possibly associated with nonreporting. Analysis was by analysis of variance and multiple linear regression with stepwise variable election. RESULTS: Two hundred fifty-nine subjects recalled 643 contaminated exposures during the five-year study period, but only 228 (35%) were formally reported. One or more injuries occurred in 55% of EMTs compared with 72% of nurses and 80% of physicians (P less than .05). Physicians recalled a mean of 3.8 contaminated exposures, whereas nurses recalled 2.8 and EMTs recalled only 1.8 (P less than .05). Physicians formally reported a mean of 0.26 exposures, whereas EMTs reported 0.85 and nurses reported 1.25 (P less than .05). Physicians formally reported only one eighth of their injuries compared with EMTs and nurses, who each reported two thirds of these events (P less than .05). Perception of risk, occupation, years in occupation, and concern about excessive paperwork were the most powerful predictors of low reporting rate (P less than .05). CONCLUSIONS: Work-related contaminated sharp object injuries are under-reported by emergency health care workers, especially emergency physicians.

The effect of local anesthetics on bacterial proliferation: TAC versus lidocaine.

We compared the effect of topical 0.5% tetracaine, 1:2,000 epinephrine, and 11.8% cocaine (TAC) with 1% lidocaine infiltration on bacterial proliferation in experimental lacerations. Forty-eight lacerations were made on the backs of Hampshire pigs, inoculated by injection with infectious doses of Staphylococcus aureus and randomly anesthetized with either topical TAC or lidocaine infiltration. Wounds were sutured, and quantitative cultures were obtained by excision after 48 hours. The mean log10 bacteria per gram of tissue for wounds anesthetized with TAC was 6.818 (95% confidence interval [CI], 6.07 to 7.54) compared with 6.820 (95% CI, 5.91 to 7.75) for those treated with lidocaine; this difference was not significant (P less than .05 by paired two-tailed t test). The probability of failing to detect an intergroup difference of 0.5 log10 bacteria per gram was less than .0001. TAC does not increase bacterial proliferation more than lidocaine infiltration in contaminated experimental porcine lacerations.

Amebic liver abscess: emergency department diagnosis.

Twelve patients with amebic liver abscess were admitted to a university hospital. Ten of these patients were admitted through the emergency department. Patients, especially men from third world countries, with fever, right upper quadrant pain, and leukocytosis are at high risk for this disease and should have the diagnosis confirmed with amebic serology and ultrasonography or computed tomography.

Anaphylaxis following administration of intravenous methylprednisolone sodium succinate.

A 27-year-old man developed respiratory arrest following intravenous administration of methylprednisolone sodium succinate. Skin tests were positive to methylprednisolone sodium succinate but not to methylprednisolone acetate. Severe anaphylactic reactions to intravenous corticosteroid medications can occur and can require epinephrine administration or endotracheal intubation. Skin tests and drug challenge should be done to establish the safety of a particular corticosteroid drug.