Clark S Homan

EVALUATION OF A TEACHING LABORATORY USING A CADAVER MODEL FOR TUBE THORACOSTOMY

A prior study evaluated the efficacy of a dog laboratory to teach residents chest tube thoracostomy. This study evaluated a similarly structured program using human cadavers. A prospective repeat measure study of chest tube thoracostomy placement training was performed in a university laboratory setting using human cadavers. Ten Emergency Medicine residents were given a written pretest, followed by training. Resident attempts were then timed. The following day, a repeat test was administered. Three weeks later, a third written post-test was conducted. The written test scores improved for every participant. Mean times for procedure completion improved from 86 sec to 34 sec during the first session, and remained stable over 4 attempts from 30 sec to 32 sec during the second session. This approach to teaching clinical procedures should be considered for Emergency Medicine residency programs and for continuing education courses that emphasize procedural skills.

Therapeutic effects of water and milk for acute alkali injury of the esophagus

STUDY BACKGROUND Alkali ingestions cause progressive and devastating injury to the esophagus by liquefaction necrosis. However, the therapeutic efficacy of water or milk dilution for alkali-induced esophageal injury has not been determined. This study used our previously reported model of alkali-induced esophageal injury to evaluate the effectiveness of water and milk dilution. HYPOTHESIS Early dilution with water or milk is efficacious in decreasing esophageal damage from alkali exposure. METHODS The esopgagi of 75 Sprague-Dawley rats were harvested, and each end was cannulated with a 20-gauge catheter. Specimens were maintained in an oxygenated saline solution (at 37 degrees C) during a 60-minute experimental period and then fixed immediately in 10% Formalin solution for histologic examination. Esophagi from six experimental groups (total of 60) were perfused with 50% NaOH solution at time 0. Water or milk dilution was performed immediately at 0 minutes, 5 minutes after injury, and 30 minutes after injury. Blinded pathologic examination was performed using a score of 0 (no injury), 1 (minimal), 2 (moderate), or 3 (severe) for the following six histologic categories: epithelial viability, cornified epithelial cell differentiation, granular cell differentiation, epithelial cell nuclei, muscle cells, and muscle cell nuclei. RESULTS Positive and negative controls showed expected outcomes. Significant progressions of injury over time were seen for every histologic category for both water and milk dilution. The injury scores for the milk-treated group at 0 minutes were less than or equal to the injury score for the water-treated group for all categories. However, these differences were significant only for the cornified epithelial cells. CONCLUSION Early dilution therapy with water or milk reduces acute alkali injury of the esophagus and supports use of these forms of emergency treatment.

In Vivo Tissue Temperature Comparison of Cryotherapy With and Without External Compression

STUDY OBJECTIVE To compare the tissue-cooling efficiency of external cryotherapy with and without adjunctive compression. METHODS We conducted an experimental repeated-measures study in which each of the 11 anesthetized subject dogs served as its own control. A chemical instant cold pack was applied to each subjects ventral thighs. One pack was held in position by gravity, and the other was compressed against the musculature with a tubular elastic wrap. Baseline and subsequent temperature measurements were taken every 10 minutes for 1 hour with the use of an IM temperature probe percutaneously inserted into each subjects hind legs. RESULTS IM temperatures were not significantly different at baseline and were coldest at 20 minutes; they increased slowly thereafter. The recorded temperature was lower under the compressed cold pack (P = .003), and changes over time for both groups were also significant (P = .005). The instantaneous temperature difference at 10, 30, 40, 50, and 60 minutes was also significant. CONCLUSION Externally applied instant cold packs in a dog model caused local tissue hypothermia that peaked by 20 minutes, persisted for at least 1 hour, and was significantly augmented by adjunctive compression. Further research is needed to evaluate the clinical efficacy and safety of these interventions in the management of acute soft-tissue injuries.

Effective treatment of acute alkali injury of the rat esophagus with early saline dilution therapy

BACKGROUND Controversy persists regarding the appropriate treatment of acute alkali injury to the esophagus. The current study establishes a controlled model of alkali esophageal injury and examines the efficacy of saline dilution therapy. STUDY HYPOTHESIS Early saline dilution therapy effectively reduces esophageal injury resulting from acute alkali exposure. METHODS The esophagi were harvested from 60 Sprague-Dawley rats. Each end was cannulated with a 20-gauge catheter. Specimens were maintained in an oxygen-perfused saline bath (37 C) during a 60-minute experimental period and then fixed immediately in 10% formalin solution for histologic examination. Three experimental groups (A, B, and C) were perfused with 50% NaOH solution at time zero. Treatment with saline perfusion was performed immediately in group A, five minutes after injury in group B, and 30 minutes after injury in group C. The positive control group D was perfused with saline at time zero. A negative control, group E, was perfused with 50% NaOH at time zero. This group did not receive subsequent treatment with saline. Pathologic examination was performed in a blinded fashion using a score of 0 to 3 (0, no injury; 1, minimal; 2, moderate; 3, severe) for seven histologic criteria: epithelial viability, extent of injury, cornified epithelial cell differentiation, granular cell differentiation, epithelial cell nuclei, muscle cells, and muscle cell nuclei. RESULTS The positive control group demonstrated scores of zero. Nonparametric analysis showed a significant difference among treatment groups for each injury category. Trend analysis revealed a significant progression of injury for each category associated with time to treatment. Discriminant analysis indicated that the muscle cells category was the most useful category with which to distinguish injury among groups. CONCLUSION In our model, saline lavage decreased objective evidence of esophageal injury after a severe alkaline exposure, and early therapy enhanced this beneficial effect.

The enlarging clinical spectrum of lyme disease: Lyme cerebral vasculitis, a new disease entity

The case of a patient with cerebral vasculitis with a right thalamic infarct associated with cerebral spinal fluid Lyme disease is presented. This entity has not been described in the United States, and only one similar case in the world literature could be found. The patient presented with a progressive headache and subsequent development of grand mal seizure activity. Lyme disease has been associated with cranial nerve palsies, peripheral and cranial radiculopathies, aseptic meningitis, encephalitic symptoms, chorea, and demyelinating polyneuropathy presenting like Guillain-Barré syndrome. These syndromes can occur separately or in combination. Stroke and strokelike syndromes have been attributed to Lyme disease. The literature concerning the neurologic manifestations of Lyme disease is reviewed.

Evolution of abstracts presented at the annual scientific meetings of academic emergency medicine.

There has been a general trend in medicine toward greater sophistication in research design. To assess this trend in emergency medicine, we compared the characteristics of abstracts presented at the 1974, 1983, 1989, and 1997 annual scientific meetings of Academic Emergency Medicine. All 870 abstracts were reviewed by 1 of 3 investigators who determined research design attributes using a standardized classification scheme that has good interrater reliability. Over the last 25 years, the following trends were noted: more surveys (0% v1% v3% v8%, P=.002), more randomized studies (0% v10% v12% v15%, P=.05), and more blinded studies (0% v7% v5% v11%, P=.01). Tests of statistical significance were reported with increasing frequency (8% v26% v59% v 69%, P < .001), as were power calculations (0% v0% v1% v3%, P=.02). During the study period, there were also increases in the median number of authors, proportion of foreign lead authors, and the proportion of studies involving human subjects. These results reflect considerable improvement in the degree of research design sophistication reported in selected abstracts of academic emergency medicine over the study period. Further strategies to assure continued enhancement of emergency medicine research should be explored.