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Biomedical subjects

B S Selden

Publications and source records attributed to B S Selden.

12 recordsLinked to original sources
PubMed1992

Optimal patient position for transport and initial management of toxic ingestions.

STUDY OBJECTIVES: Many factors influence the rate of gastric emptying and therefore the rate of drug absorption in the orally poisoned patient. Limited studies have evaluated the effect of body position on the rate of gastric emptying of radiographically marked foods and contrast media, but effects on drug absorption have not been studied previously. Our hypothesis was that body position would have an effect on the rate of drug absorption in an oral overdose model. DESIGN: A blinded, within-subjects (crossover) design. PARTICIPANTS: Six male and six female healthy, adult volunteer subjects with no concurrent drug use or medications affecting gastrointestinal function. INTERVENTIONS: Five body positions commonly used in prehospital and emergency department settings were examined: left lateral decubitus, right lateral decubitus, supine, prone, and sitting. All were performed by all subjects in random order with a three-day washout phase between trials. To simulate an acute overdose, fasted subjects ingested 80 mg/kg acetaminophen in the form of 160-mg pediatric tablets. Each subject then remained in the body position for that trial for two hours. Acetaminophen levels were obtained at 15-minute intervals, and a two-hour area under the curve (AUC) was calculated for each subject trial to represent total drug absorption during each study period. Investigators were blinded to all results until all trials were completed. MEASUREMENTS AND MAIN RESULTS: All subjects completed the study. Group mean drug absorption as represented by two-hour AUC (mg.L.min) was calculated for each body position. AUC for left lateral decubitus (6,006 +/- 2,614) was lowest but did not significantly differ from that for supine (6,649 +/- 2,761). Both were significantly less than those for prone (7,432 +/- 1,809), right lateral decubitus (8,950 +/- 1,405), and sitting (8,608 +/- 1,725) positions (P less than .05 by one-way analysis of variance and follow-up paired t tests). CONCLUSION: Initial drug absorption as determined by two-hour AUC was lowest in the left lateral decubitus position. Although the difference between the left lateral decubitus and supine positions did not reach statistical significance, both left lateral decubitus and supine were significantly lower than three other common patient body positions tested. Because the left lateral decubitus position has other advantages (eg, prevention of aspiration) in addition to minimizing drug absorption, we recommend that orally poisoned patients be placed in the left lateral decubitus position for prehospital and initial ED management.

Acetaminophen↗
PubMed1991

Transplacental transport of N-acetylcysteine in an ovine model.

STUDY OBJECTIVE: Acetaminophen freely crosses the placenta, and acetaminophen ingestion is the most frequent intentional overdose in pregnancy. Although most patients do well after maternal treatment with the antidote N-acetylcysteine (NAC), fetal death with massive hepatic necrosis has occurred. It has never been shown whether NAC crosses the placenta to yield fetal plasma levels equal to those associated with hepatoprotective effects in human beings. Our study objective was to evaluate this in a widely accepted large animal model for maternal-fetal research. DESIGN AND TYPE OF PARTICIPANTS: A nonblinded experiment was performed using four domestic sheep at near-term gestation. INTERVENTIONS: NAC 150 mg/kg IV was administered to the ewe over 15 minutes. After induction of anesthesia, the fetal head was delivered surgically and a neck vein cannulated for blood sampling. Maternal and fetal blood samples were obtained at the end of NAC infusion, at 30- and then at 60-minute intervals for four hours. Plasma NAC levels were determined by gas chromatography/mass spectroscopy (detection limit, 2 micrograms/mL; quantification limit, 5 micrograms/mL). RESULTS: Maternal peak plasma NAC levels were 619, 631, 1,757, and 2,512, micrograms/mL, respectively, within 30 minutes of infusion. However, NAC was only minimally detectable in plasma of two fetal animals and transiently reached quantifiable levels in two others. None of the fetal animals attained serial plasma NAC levels that equalled those associated with therapeutic dosing or hepatoprotective effects in human beings. CONCLUSION: Transplacental transport of NAC is clinically insignificant in a mammalian model resembling the human being. These findings suggest that the human fetal liver is not protected from acetaminophen toxicity by maternal NAC therapy.

Acetylcysteine↗
PubMed1991

Digoxin-specific Fab fragments in the treatment of oleander toxicity in a canine model.

STUDY OBJECTIVE: To examine the efficacy of digoxin-specific Fab fragments (dsFab) in the treatment of experimentally induced Nerium oleander cardiac glycoside toxicity in a dog model. DESIGN: A nonblined, placebo-controlled experiment. SUBJECTS: Ten adult greyhound dogs of either sex divided into treatment and control groups of five dogs each. INTERVENTIONS: A tincture of oleander was prepared and administered intravenously to each animal. After the onset of cardiotoxicity, the treatment group received 60 mg/kg dsFab IV. MEASUREMENTS AND MAIN RESULTS: All dogs exhibited dysrhythmias meeting our criteria for cardiac glycoside cardiotoxicity within 27 minutes of beginning the infusion. Three of five control dogs had lethal dysrhythmias during the three-hour observation period. The remaining two control dogs exhibited dysrhythmias throughout the three-hour experiment. All five of the dsFab-treated dogs survived and converted to normal sinus rhythm within eight minutes of dsFab infusion. Three treatment animals reverted back to nonlethal and hemodynamically stable dysrhythmias after a mean of 107 minutes. CONCLUSION: Large doses of dsFab are efficacious in the treatment of dysrhythmias in this canine model of N oleander cardiac glycoside poisoning.

Animals↗
PubMed1990

Medicolegal documentation of prehospital triage.

Patients evaluated by paramedics but not transported to the hospital account for 50% to 90% of emergency medical services lawsuits. We reviewed 2,698 consecutive paramedic run reports to examine documentation in these cases. Documentation criteria for prehospital patient release were history, physical examination, vital signs, mental status, lack of significant mental impairment, and for patients refusing care, that risks of refusing were understood. Criteria for appropriate release were met in 65.2% of cases. Criteria omitted in inappropriate releases were risks of refusing care in 481 (51.3% of inappropriate releases), vitals in 320 (34.1%), mental status in 188 (20.0%), lack of impairment in 120 (12.8%), and history or physical in 19 (2.0%) cases. Age from 0 to 14 and 65 or more years and prehospital assessment of hyperventilation, psychiatric emergency, choking, infection, and patient deceased were significantly associated with appropriate release. Age from 35 to 54 years and prehospital diagnosis of no injury, head injury, seizure, minor trauma, and ethanol use were significantly associated with inappropriate releases. There was no association of appropriate release or inappropriate release with patient sex, contact with medical control, length of encounter, or time of day. Only one patient complication was believed due to inappropriate triage; this could be improved by implementation of standardized criteria.

Adult↗
PubMed1990

Marijuana.

Marijuana remains a complex, poorly understood drug with many effects. Although its acute psychological effects are well described, data linking cannabis use to chronic psychiatric or social problems and decreased driving or workplace safety are much less clear. Current laboratory procedures have not yet been shown useful to demonstrate acute intoxication, so they remain screening instruments for those interested in detecting cannabis use for other reasons. Although both acute and chronic effects of marijuana use have been described, they appear to be less than other commonly abused substances, including tobacco and alcohol. The rare acute complications that present to the Emergency Department can be managed with conservative measures.

Ambulatory Care↗
PubMed1989

Adolescent epidemic hysteria presenting as a mass casualty, toxic exposure incident.

Discussed is a case of explosive epidemic hysteria presenting as a mass casualty, toxic inhalation incident. Fifteen adolescent female students were triaged from a school of 700 persons exposed to sewer gas and arrived simultaneously at the emergency department complaining of a variety of nonspecific symptoms without physical findings. These symptoms quickly remitted with reassurance and dispersion of the group. Factors important in the recognition and treatment of epidemic hysteria are presented.

Accidents↗
PubMed1988

Outcome of self-inflicted gunshot wounds of the brain.

A consecutive series of 67 patients who had sustained self-inflicted gunshot wounds of the brain was reviewed retrospectively to evaluate factors determining outcome. Weapon caliber, site of bullet entry, degree of brain wounding on computerized tomographic scan, and presenting Glasgow Coma Scale (GCS) score were examined. Overall mortality, degree of disability in survivors, and survival time after injury in fatally wounded patients were assessed. Ninety-eight percent of all patients with an initial GCS score of 8 or less died. When the GCS score was more than 8, 91% of patients survived (P less than .0001). Survival rate was significantly increased in patients with injury limited to one lobe of the brain, compared with patients with brain wounds of greater severity demonstrated on computerized tomographic scan (P less than .05), while a missile crossing both vertical anatomic planes of the brain or coming to rest in the posterior fossa was lethal in 100% of cases. Survivors scored relatively well on the Glasgow Outcome Scale. Almost all (98%) fatally injured patients maintained vital functions for a time ample for transportation and evaluation at a major referral center. These findings hold important implications for trauma center and critical care resource allocation as well as organ transplantation programs.

Adolescent↗
PubMed1988

Complete maternal and fetal recovery after prolonged cardiac arrest.

A case of complete maternal and fetal recovery after prolonged cardiac arrest from massive lidocaine overdose is presented. A 27-year-old woman at 15 weeks gestation had a complete neurologic recovery after 22 minutes of CPR, including 19 minutes of electromechanical dissociation and asystole, with normal fetal heart function and fetal motion confirmed by ultrasound immediately after resuscitation. The patient delivered a healthy and neurologically normal infant at 40 weeks gestation. This is the longest cardiac arrest in early pregnancy reported in the medical literature with normal maternal and fetal outcome.

Adult↗
PubMed1987

Prolonged succinylcholine-induced paralysis in organophosphate insecticide poisoning.

A case of prolonged succinylcholine-induced paralysis in a child with organophosphate insecticide poisoning is presented. Three hours and 15 minutes of apnea after the administration of succinylcholine was attributed to a decreased rate of succinylcholine metabolism from inhibition of pseudocholinesterase by the insecticide. Only one similar case has been reported previously in the English medical literature. If succinylcholine is to be used in patients with organophosphate poisoning, a prolonged paralysis should be anticipated.

Apnea↗