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Biomedical subjects

D E Hogan

Publications and source records attributed to D E Hogan.

12 recordsLinked to original sources

The emergency department approach to diarrhea.

Enteric disease represents a significant medical problem on a worldwide basis. The evaluation of patients with diarrhea in the emergency department should follow a stepwise methodology to identify potentially serious disorders. The evaluation of the stool for fecal leukocytes is an important differentiation point in the evaluation of the moderately to seriously ill diarrhea patient. Oral rehydration alone can treat the vast majority of diarrhea patients. Oral rehydration solution takes advantage of the sodium glucose coupled active absorption mechanism, which is largely unaffected by enteric toxins. Antimicrobial or antidiarrheal agents are rarely indicated in the treatment of diarrhea.

Diarrhea

When a snake bites.

Primary care physicians may be required to treat snake-bitten patients and must differentiate between venomous and nonvenomous snakes. The chief distinguishing characteristics of venomous snakes are fangs and a single row of subcaudal anal plates. The physiologic effects of snake venom are on the cardiovascular, hematologic, and neurovascular systems. The snake-bitten patient first needs supportive treatment and stabilization. Then, the physician must establish whether envenomation has occurred, grade it, and monitor edema around the bite. Local treatment, broad-spectrum antibiotics, and tetanus prophylaxis should be used for all envenomation grades. The decision to administer antivenin therapy should be made on clinical grounds and the envenomation grade. Its use, however, can lead to anaphylaxis and anticomplement reactions.

Anti-Bacterial Agents

Double-blinded comparison of diphenhydramine versus lidocaine as a local anesthetic.

STUDY OBJECTIVE: To evaluate the efficacy, onset of action, duration of action, and side effects of 1% diphenhydramine compared with 1% lidocaine when used as a local anesthetic agent. DESIGN: Prospective, double-blinded, cross-over study. SETTING: Emergency medicine residency program, research section. PARTICIPANTS: Ten healthy male volunteers, aged 26 to 38 years old. INTERVENTIONS: Baseline levels of sensation to pinprick (18-gauge needle) within a 2.4-cm-diameter midvolar forearm area and levels of sedation were recorded on 10.2-cm visual analog scales. Subjects then underwent subcutaneous infiltration of 20 mg (2 mL) of the study agent using a 27-gauge needle. Visual analog scale sensation and sedation scores were recorded at five, ten, and 15 minutes and then every 15 minutes until return to baseline. Subjects were studied one week later with the alternate agent. Nonparametric data were analyzed using the Mann-Whitney U test with significance at P < .05. RESULTS: No significant differences in mean pinprick sensation were seen from baseline to 30 minutes. Significant differences were seen at 45 (P = .036) and 60 minutes (P = .036). The mean duration of effective anesthesia was significantly longer for lidocaine than diphenhydramine (81 versus 42 minutes, P = .028). No significant differences were seen in the sedation scores or in the frequencies of local reactions. One subject developed skin necrosis at the injection site with diphenhydramine. CONCLUSION: The duration of local anesthesia for 1% lidocaine was significantly longer and the depth of anesthesia after 30 minutes was significantly higher than that of 1% diphenhydramine. Diphenhydramine resulted in skin necrosis in one test subject.

Adult

Venomous snakes of southwest Asia.

This report provides a brief description of the venomous snakes encountered in Southwest Asia, as well as a brief review of the clinical implications of envenomation from each animal. Specific therapy for snake envenomation in the United States is somewhat controversial, and it is no less controversial with animals from this region. The most logical approach probably combines medical management with antivenom when available, and surgical intervention when clearly indicated due to elevated compartment pressure or massive tissue necrosis. Antivenom is available for all species except W aegyptia (in vitro only) and Atractaspis species. Antivenom for V palaestinae may be used for Atractaspis envenomation (Tables 2 and 3).

Animals

Prophylactic oral antibiotics for low-risk dog bite wounds.

The use of prophylactic antibiotics in the initial treatment of noninfected dog bite wounds is controversial. All patients with noninfected dog bite wounds who presented to our emergency department (ED) over a two-year period were considered for entry into a randomized prospective study. Patients were excluded from the study if they had any high-risk criteria for infection: puncture wounds, hand or foot wounds, wounds greater than 12 hours old, a history of immunocompromising disorders, or the use of immunosuppressive drugs. Patients in the antibiotic group (n = 89) were treated with local wound care and given either dicloxacillin, cephalexin, or erythromycin orally for seven days. Patients in the control group (n = 96) received local wound care only. All patients had their wounds irrigated with a 1% povidone-iodine solution and debrided and sutured if clinically indicated. All patients were subsequently reevaluated for clinical signs of wound infection. The groups were similar in age, sex, time of delay in seeking treatment, anatomic sites of wounds, depths and types of wounds, and number of wounds requiring suturing. The wound infection rates for the antibiotic and control groups were 1.1 and 5.1%, respectively. This difference was not significant (P = 0.212). There were 36 wounds in the antibiotic group and 37 wounds in the control group that were full thickness. The infection rates for these wounds were 2.8 and 13.5%, respectively. This was not statistically significant (P = 0.132). This study suggests that prophylactic oral antibiotics in low-risk dog bite wounds are not indicated.

Administration, Oral

Imaging after head trauma. Who needs what?

Decisions about the optimal imaging strategy in patients after acute head trauma can be based on clinical observations. Low-risk patients do not require radiographic imaging. CT is the procedure of choice for imaging moderate- and high-risk patients after head trauma. Because of its limited ability to guide therapy, plain skull radiography should be used sparingly; it may be useful in equivocal cases of bony injury not detected by CT or in selected moderate-risk patients (especially children under the age of 2 years). MR imaging rivals CT in the detection of intracranial injuries but is more expensive and cumbersome in seriously ill subjects and does not image bony structures. MR imaging is recommended after initial CT if subtle acute nonhemorrhagic and subacute hemorrhagic lesions are suspected, especially in the evaluation of child abuse. Otherwise, MR imaging is rarely needed in the emergency department management of acute head injury patients.

Craniocerebral Trauma

Anaphylactic shock secondary to rattlesnake bite.

Anaphylactic reactions to Crotalidae envenomation are extremely rare. The presentation of anaphylaxis after envenomation can be a confusing variable in the timely diagnosis of both problems. The therapy of this dual disorder involves combining treatment of the obvious shock from the allergic reaction with a standard approach to Crotalidae envenomation. We present the case of a 22-year-old man who presented to the emergency department with urticaria, hypotension, and bronchospasm that developed immediately after his second envenomation from a rattlesnake. His symptoms resolved after administration of 0.8 mg SQ epinephrine, 100 mg IV diphenhydramine, 2,000 mL normal saline IV, and 250 mg IV methylprednisolone. Only one previous case report of anaphylactic shock from a rattlesnake bite could be found in the medical literature.

Adult

Control of pigeons' matching-to-sample performance by differential sample response requirements.

Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice.

Animals

Oddity learning in the pigeon as a function of the number of incorrect alternatives.

Pigeons' rate of learning a two-color oddity task increased as a function of the number of incorrect alternatives from 2 to 24 in Experiments 1, 2, and 3. In general, pigeons that were transferred from many-incorrect-alternative to two-incorrect-alternative oddity performed better than controls, but considerably below baseline (Experiments 2 and 3). In Experiment 4, pigeons showed no unconditioned tendency to peck the odd stimulus among 24 incorect alternatives, when pecks were nondifferentially reinforced, and in Experiment 5, when this procedure was preceded by oddity training, a progressive drop in odd-stimulus pecking was found. In Experiment 6, pigeons exposed to a nine-stimulus array in which the odd stimulus appeared (a) in the center or (b) separate from the array learned faster than when the odd stimulus was at the edge. This outcome suggests ththe figure-ground relation between the odd stimulus and the incorrect alternatives plays a role in the facilitation produced by increasing the number of incorrect alternatives but that poor performance on the standard, three-alternative oddity task appears to be due to center-odd trials which provide a difficult size or number discrimination.

Animals

The medical impact of tornadoes in North America.

North America suffers some of the most severe tornado disasters of any location on the planet. Significant injury and economic impact may result from these storms, particularly in rural areas. Tornadic storms present unique problems for prehospital and Emergency Department personnel. Soft tissue injuries seen after tornadoes are contaminated with polymicrobial flora and may require delayed primary closure. Fractures are a frequent cause of hospital admission and head injury is a frequent cause of death. Advanced warning and proper sheltering actions by a population are the most significant factors in reducing morbidity and mortality. This article reviews the pertinent literature on the medical impact of tornadoes and details the mechanisms of injury, nature of injuries, pre-hospital and ED planning points associated with tornadic storms.

Canada

A prospective evaluation of risk factors for infections from dog-bite wounds.

OBJECTIVE: To define risk factors for infections from dog- bite wounds and to model the probability of wound infection in patients presenting without infection who are treated as outpatients. METHODS: A prospective survey of 769 consecutive dog-bite victims presenting over a two-year period to a community hospital emergency department (ED) with an emergency medicine residency program. A standardized wound-cleaning protocol was used, which included debridement and wound closure when indicated. Wounds were examined for infection at follow-up. Variables analyzed included demographic data (patient age, gender, race); wound information (wound age, type, number, location, depth); and treatment (prior to hospital, ED debridement, suturing, tetanus or rabies shots, antibiotics). RESULTS: There were 734 patients with complete records. These patients had a mean age of 13.4 +/- 13.2 years (range, 4 months to 71 years). Infection was evident in 2.5% of the wounds upon presentation. There were 704 patients (765 wounds) managed as outpatients and without wound infection upon presentation. Wounds were distributed as follows: 26.7% head/neck, 20.4% hand, 15.7% arm, 10.1% trunk, 9.5% thigh, 15.9% leg, and 1.7% foot. There were 32.9% puncture, 39.9% full-thickness, and 60.1% partial-thickness wounds. Wound infections were diagnosed in 2.1% Of these wounds at follow-up. Wounds requiring surgical debridement had a sevenfold higher infection rate (p = 0.01). Patients more than 50 years of age had a sixfold higher infection rate than younger patients (p = 0.05). Stepwise logistic regression found the following variables to be the best predictors for wound infection: full-thickness [p = 0.006, odds ratio (OR) = 6.23], female gender (p = 0.048, OR = 2.88), and wound debridement (p = 0.024, OR = 5.01). Combinations of these three variables predict infection rates from 0.35% to 23.9%. CONCLUSION: A low wound infection rate was seen in this cohort of dog-bite victims who were treated on an outpatient basis. Wound depth, patient gender, and wound debridement were the clinical variables that best predicted the likelihood of developing infection. Future interventional studies should concentrate on wounds with high probabilities of infection.

Adolescent