Reminiscing on military duty in Iraq.
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Iraq↗
Biomedical subjects
David A Tanen
Publications and source records attributed to David A Tanen.
Crotalidae polyvalent immune Fab (ovine) antivenom is effective in the neutralization of South American viperidae venoms in a murine model.
STUDY OBJECTIVE: Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) is used in the treatment of symptomatic crotaline envenomations in North America. Unlike Antivenin (Crotalidae) Polyvalent, which is approved for treatment of crotaline envenomation in North and South America, FabAV is manufactured using only venoms from crotaline snakes native to the United States. This study was designed to evaluate the efficacy of FabAV in the neutralization of venom from 2 South American crotaline snakes: Crotalus durissus terrificus (tropical rattlesnake) and Bothrops atrox (fer-de-lance). METHODS: A randomized, blinded, placebo-controlled murine model of intraperitoneal venom injection was used. Venom potency was determined in preliminary median lethal dose (LD 50) dosing studies. Study animals were then divided into 7 groups: (1) C durissus terrificus venom (Sigma-Aldrich Co.)+FabAV, (2) C durissus terrificus venom (Sigma-Aldrich Co.)+0.9% normal saline solution, (3) C durissus terrificus venom (Biotoxins Inc.)+FabAV, (4) C durissus terrificus venom (Biotoxins Inc.)+normal saline solution, (5) B atrox venom+FabAV, (6) B atrox venom+normal saline solution, and (7) FabAV+normal saline solution. Twice the estimated LD 50 was the chosen venom dose, and the amount of FabAV injected was 10 times the amount needed for venom neutralization. Statistical analysis included Fisher's exact test and log-rank testing to compare survival rates and times. RESULTS: The venom LD 50 was found in preliminary studies to be 0.9 mg/kg and 1.35 mg/kg for the C durissus terrificus venom obtained from Sigma-Aldrich Co. and Biotoxins Inc., respectively. The LD 50 for B atrox venom was 5.0 mg/kg. All animals receiving venom only and saline solution died. Animals receiving FabAV together with either venom survived to the end of the 24-hour observation period ( P <.001). Comparison of survival times between groups demonstrated a significant difference in time to death between venom-only control groups and the FabAV+venom groups (P <.001). All animals in the FabAV+normal saline solution group survived to the conclusion of the study. CONCLUSION: FabAV, when premixed with venom, decreases lethality in a murine model of intraperitoneal venom injection of the South American pit vipers, C durissus terrificus and B atrox .
Animals↗
Kikuchi's disease: a rare cause of cervical lymphadenitis and fever.
Cervical lymphadenitis and fever are common in patients presenting to the Emergency Department (ED). Kikuchi's disease is a rare, self-limited cause of fever and cervical lymphadenitis often misdiagnosed as lymphoma or lupus and inappropriately treated, potentially causing numerous ED visits for unrelieved symptoms. The case described is that of a 29-year-old with persistent fever and cervical lymphadenitis who presented to the ED with a suspected allergic reaction to an antibiotic. The diagnosis of Kikuchi's disease was made in association with nasopharyngeal carcinoma and partial hydatidiform mole. The case highlights the clinical features, diagnosis, and treatment of Kikuchi's disease.
Adult↗
Fasciotomy worsens the amount of myonecrosis in a porcine model of crotaline envenomation.
STUDY OBJECTIVE: We evaluate the efficacy of fasciotomy or crotaline snake antivenom in reducing myonecrosis. METHODS: We used a randomized, blinded, controlled acute animal preparation. Twenty anesthetized swine were injected intramuscularly in the anterior tibiales muscle of both hind limbs with 6 mg/kg of Crotalus atrox venom (total of 12 mg/kg of venom per animal). Immediately after venom injection, the right hind limb underwent fasciotomy. Muscle biopsies were obtained from the fasciotomized hind limb at 0, 4, and 8 hours and from the other hind limb at the conclusion of the study (8 hours). In addition, animals received either 8 vials of reconstituted Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) or an equal volume of normal saline solution intravenously 1 hour after venom injection. A pathologist blinded to the study determined the percentage of myonecrotic cells in each biopsy. Statistical analysis was performed using repeated measures analysis of variance for compartment pressure. Rank-order methods were used for comparison of myonecrosis between groups. RESULTS: Biopsies from hind limbs undergoing fasciotomy revealed a progressive increase in the amount of myonecrosis over time (myonecrosis median at 0, 4, or 8 hours [or death]: 0%, 14%, or 14.5%, respectively; P<.001). Comparison of the amount of myonecrosis of biopsies at death or 8 hours revealed that limbs that underwent fasciotomy had significantly more myonecrosis than those that did not (myonecrosis median: 14.5% versus 2.5%, P=.048). No difference was detected in the amount of myonecrosis when FabAV was compared with normal saline solution on final biopsies from either fasciotomy or nonfasciotomy hind limb (myonecrosis median: 10.0% versus 10.0%, P=.64). CONCLUSION: Fasciotomy significantly worsens the amount of myonecrosis in a porcine model of intramuscular crotaline venom injection. No change in the amount of myonecrosis was detected with the use of FabAV treatment at the dosages used in this animal model.
Animals↗
Pressure immobilization delays mortality and increases intracompartmental pressure after artificial intramuscular rattlesnake envenomation in a porcine model.
STUDY OBJECTIVES: We determine the effect of pressure immobilization on mortality and intracompartmental pressure after artificial intramuscular Crotalus atrox envenomation in a porcine model. METHODS: We prospectively studied 20 pigs using a randomized, controlled design. After anesthesia, C atrox venom (20 mg/kg) was injected with a 22-gauge needle 10 mm deep into the tibialis anterior muscle of the hind leg. Pigs were randomized to receive either pressure immobilization (applied 1 minute after envenomation and maintained throughout the duration of the experiment) or no pressure immobilization. We measured time to death, intracompartmental pressure before venom injection and at 2 hours after injection, and leg circumference at a standardized location before injection and immediately postmortem. Duration of survival was compared using Kaplan-Meier survival analysis. RESULTS: The dose of venom resulted in 100% mortality. The median survival was longer in the pressure immobilization group (191 minutes, range 140 to 240 minutes) than in the control group (median 155 minutes, range 119 to 187 minutes). The difference between the groups was 36 minutes (95% confidence interval [CI] 2 to 64 minutes; P =.0122). The mean intracompartmental pressures were 67+/-13 mm Hg+/-SD with pressure immobilization and 24+/-5 mm Hg without pressure immobilization. The difference between groups was 43 mm Hg (95% CI 32 to 53 mm Hg). The mean circumferences were 14.3 cm in the pressure immobilization group and 19.1 cm in the control group. The difference between groups was -4.8 cm (95% CI -5.7 to -3.9 cm). CONCLUSION: Compared with control animals without treatment, the pressure immobilization group had longer survival, less swelling, and higher intracompartmental pressures after artificial, intramuscular C atrox envenomation in our porcine model.
Animals↗
A reassessment of topical organic phosphorus insecticide exposures and permanent paralysis.
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Acetylcholinesterase↗
Intravenous sodium valproate versus prochlorperazine for the emergency department treatment of acute migraine headaches: a prospective, randomized, double-blind trial.
STUDY OBJECTIVE: We compare the efficacy of intravenous sodium valproate versus prochlorperazine for the emergency department treatment of acute migraine headache. METHODS: We performed a randomized, prospective, double-blind trial performed at a tertiary care military ED. Forty patients, aged 18 to 65 years, presenting with typical migraine symptoms were enrolled. Patients were randomized to receive either 10 mg of prochlorperazine or 500 mg of valproate intravenously over 2 minutes. Pain, nausea, and sedation were assessed by using a standard visual analog scale (VAS). Changes in VAS scores were compared between groups from baseline to end point by using a rank sum test, over time by using 2-way repeated-measures analysis of variance, and by requirement for rescue at 60 minutes by using the Fisher exact test. RESULTS: Comparison of the change in median VAS scores over 60 minutes revealed that sodium valproate was significantly less effective than prochlorperazine in reducing pain or nausea (P <.001). Median improvements in VAS pain scores (binomial confidence intervals) were as follows: 64.5 mm (48.1 to 75.6 mm) for prochlorperazine versus 9 mm (-3 to 39.6 mm) for sodium valproate. Median improvements in VAS nausea scores were as follows: 35.5 mm (13.2 to 47.9 mm) for prochlorperazine versus 2 mm (-1.3 to 11 mm) for sodium valproate. There was no significant difference (P =.603) detected in the median changes in VAS scores for sedation: -4 mm (-29.9 to 8.6 mm) for prochlorperazine versus 0 mm (-6.6 to 6 mm) for sodium valproate. Comparison of the mean VAS time curves for pain and nausea also demonstrated a significant difference (both P <.001) but not for sedation (P =.232). In post hoc analysis, valproate failed to elicit significant improvement in pain or nausea scores over time, whereas prochlorperazine improved pain by 30 minutes (P <.001) and nausea by 15 minutes (P =.002). At the conclusion of the study, 15 (79%) of 19 patients receiving valproate required rescue treatment compared with 5 (25%) of 20 patients receiving prochlorperazine (P <.001). CONCLUSION: Prochlorperazine was statistically and clinically superior to sodium valproate for the treatment of the pain and nausea associated with acute migraine headaches.
Acute Disease↗
Swimming-induced pulmonary edema.
Pulmonary edema of water immersion, which is not associated with aspiration or a closed glottis, is infrequently described in the literature. Swimming-induced pulmonary edema is a syndrome whose pathophysiologic characteristics have not been fully elucidated. Immersion alone has marked effects on central vascular volume, redistribution of pulmonary blood flow, and lung volumes. These changes are more prominent in cold water. These changes, coupled with an elevated cardiac output, may expose regions of the capillary bed to high pressures that favor the extravasation of fluid by hydrostatic forces and potential stress failure of the capillaries. Patients with swimming-induced pulmonary edema present with dyspnea, cough, hypoxemia, and occasionally hemoptysis. Physical examination and chest radiographs usually reveal evidence of pulmonary edema. Treatment is symptomatic and conservative. Improvement and resolution of symptoms are usually rapid, with radiographic normalization in 24 to 48 hours. We describe here 3 cases of swimming-induced pulmonary edema.
Adult↗
Crotalidae polyvalent immune Fab antivenom limits the decrease in perfusion pressure of the anterior leg compartment in a porcine crotaline envenomation model.
STUDY OBJECTIVE: Crotalidae Polyvalent Immune Fab (CroFab; FabAV) antivenom prevents a decrease in perfusion pressures in intramuscular crotaline envenomation compared with normal saline solution. METHODS: We used a randomized, blinded, controlled acute animal preparation. Twenty anesthetized and instrumented swine were injected intramuscularly with 6 mg/kg Crotalus atrox venom into the anterior tibialis muscle of each hind limb (time 0). One hour after envenomation (time 1 hour), animals were randomized to receive 8 vials of reconstituted FabAV or an equal volume of normal saline solution (control) through a central venous line. The main outcome variable was the area under the perfusion-time curve (AUC) of the anterior compartment of the hind limb measured from time 1 hour to time 8 hours. Perfusion pressure was defined as mean arterial pressure-compartment pressure. Additionally, physiologic variables, including pulse rate, prothrombin time, fibrinogen level, platelet count, hemoglobin level, and hematocrit level, were monitored. RESULTS: Venom injection resulted in a decrease in average perfusion pressures from 54.1 mm Hg (time 0) to 31.7 mm Hg (time 1 hour). Comparison of AUC between groups from time 1 hour (time of treatment) to the completion of the study at time 8 hours revealed a 57% greater AUC in animals that received FabAV (mean+/-SD: 211.1+/-67.9 versus 134.5+/-55.8 mm Hg/h; P =.036; 95% confidence interval for difference 5.9 to 147.3). Comparison of the time curves for the mean prothrombin time from time 1 hour to the completion of the study by means of repeated-measures analysis of variance revealed a significant increase in the control group (P =.02). No significant difference was detected in the time curves for the means of mean arterial pressure, compartment pressure, pulse rate, hemoglobin level, hematocrit level, fibrinogen level, or platelet count over the course of the study. FabAV was found to significantly increase survival time when compared with the effect of the normal saline solution control from time 1 hour to time 8 hours, as determined by means of Kaplan-Meier estimation and the log-rank test (P =.029). CONCLUSION: FabAV limits the decrease in perfusion pressures in the anterior leg compartment after intramuscular crotaline venom injection in swine compared with saline solution. In addition, FabAV might prevent the development of coagulopathy and increase survival time in this model.
Animals↗
Respiratory compromise in patients with rattlesnake envenomation.
Respiratory compromise after rattlesnake envenomation (RSE) is an uncommon yet potentially lethal complication. We were interested in determining the frequency of respiratory compromise in patients treated for RSE. The incidence and indications for intubation were also determined. A retrospective chart review was conducted of all patients treated by medical toxicologists at a tertiary referral hospital between July, 1994 and November, 2000. Out of 294 total patients, 289 charts were reviewed. Of all 289 patients, 214 (74%) received Crotalidae Polyvalent Antivenin (Wyeth-Ayerst) and 23 (8%) had clinical evidence of respiratory compromise. Thirteen of 289 patients (4.4%) were intubated following RSE. No one was intubated for antivenin-induced complications. There were no deaths among studied patients during acute hospitalization. Respiratory compromise following RSE is rare, occurring in only 8% of studied patients. Only 2 patients (0.7%) required intubation as a direct consequence of RSE. No one required intubation for antivenin-induced hypersensitivity reactions.
Animals↗
The use of pulse oximetry to exclude pneumonia in children.
The objective of this study was to determine whether pulse oximetry alone or in conjunction with the clinical examination is predictive of pneumonia in children who present to the emergency department with respiratory complaints. A retrospective comparison of children with radiographic pneumonia with children with respiratory complaints and negative chest radiography was used. The study took place in an emergency department of a large academic, tertiary care hospital. All children less than 24 months of age who presented with a respiratory complaint and underwent chest radiography during a 1-year period were included. Charts of children with radiographic pneumonia were compared with charts of children without pneumonia, retrospectively. Data abstracted onto data collection forms included: pulse oximetry measurement, vital signs, general appearance, lung examination, and final radiology interpretation of chest radiographs. Pneumonia was defined as a chest radiograph showing any opacity consistent with pneumonia as read by a board-prepared or -certified radiologist. A total of 803 children qualified for the study. Radiograph interpretations were available for 762, and 10.5% were found to have radiographic pneumonia. The median pulse oximetry reading of children with radiographic pneumonia was 97% (interquartile range 95th-98th percentile) compared with 98% (interquartile range 96th-99th percentile) in the control group. Forty-five percent (35 of 78) of the children with radiographic pneumonia showed oxygen saturations of 98% or higher with greater than 10% (8 of 78) displaying oxygen saturations of 100%. By using logistic regression, pulse oximetry was not found to be a statistically significant predictive variable for radiographic pneumonia. Pulse oximetry could not be used to rule out the presence of radiographic pneumonia in children less than 2 years of age who presented with respiratory complaints.
Humans↗
Hypertonic sodium bicarbonate for Taxus media-induced cardiac toxicity in swine.
OBJECTIVE: To determine whether intravenous (IV) hypertonic sodium bicarbonate is effective in the reversal of QRS widening associated with severe Taxus intoxication. METHODS: Seventeen anesthetized and instrumented swine were poisoned with an IV extract of Taxus media until doubling of the QRS interval on electrocardiography was achieved. After poisoning (time zero), the animals received either 4 mL/kg IV 8.4% sodium bicarbonate (experimental group; 6 animals), a similar volume of 0.7% NaCl in 10% mannitol (mannitol group; 6 animals), or nothing (control group; 5 animals). The main outcome parameter was QRS duration. Secondary outcome parameters were mean arterial pressure (MAP), heart rate (HR), and cardiac index (CI = cardiac output/kg). Additionally, arterial pH, partial pressure of carbon dioxide (pCO(2)), and plasma-ionized calcium, sodium, and potassium were monitored. RESULTS: Taxus toxicity, defined as a 100% increase in QRS duration, was produced in all animals. The animals were similar in regard to baseline and time 0 physiologic parameters as well as amount of Taxus media extract administered. From times 5 through 30 minutes, following assigned treatment, significant increases in QRS duration were detected in the experimental and mannitol groups compared with the control group. A significant lowering of MAP was found in the experimental group compared with the control group. No significant difference between groups was noted in HR or CI. The swine treated with hypertonic sodium bicarbonate had a statistically significant increase in pH, plasma sodium concentration, and base excess compared with the other groups. CONCLUSIONS: Hypertonic sodium bicarbonate was ineffective in reversing the widening of QRS interval associated with Taxus poisoning in this swine model.
Animals↗