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Biomedical subjects

H A Bessen

Publications and source records attributed to H A Bessen.

17 recordsLinked to original sources
PubMed1990

Acute psychosis after amantadine overdose.

Amantadine is an antiviral agent that is also used in the treatment of parkinsonism and neuroleptic-induced extrapyramidal symptoms. Toxic effects of amantadine relate primarily to the central nervous system and range from mild symptoms to disorientation and hallucinations. Anti-cholinergic agents may exacerbate these effects. We report a case of unsuspected amantadine overdose in a previously healthy 35-year-old woman who presented with acute psychosis manifested by delirium and visual hallucinations. Concomitant use of diphenhydramine contributed to the clinical presentation. Amantadine toxicity should be considered in the differential diagnosis of altered mental status in patients known to be taking the drug or with conditions commonly treated with amantadine.

Adult↗
PubMed1990

Sequential clinical trials in emergency medicine.

In a traditional clinical trial, a fixed number of patients are evaluated before the data are analyzed. This has the disadvantage that more patients may be enrolled than are necessary to achieve a statistically significant result. Sequential statistical techniques provide a method for the analysis of clinical trials so that a reliable result is obtained with a minimum number of patients. In a sequential trial, the data are analyzed after each patient's outcome is known, and the trial is halted as soon as treatment efficacy or lack thereof is demonstrated. This study was undertaken to confirm the advantages of sequential statistical techniques over conventional fixed-sample-size statistical techniques for the analysis of clinical trials. Using sequential techniques, we conducted computer simulations of two fixed-sample-size clinical studies from the literature - a trial of hepatitis B vaccine in homosexual men (N Engl J Med 1980;303:833-841) and a trial of the pneumatic antishock garment in hypotensive patients with penetrating abdominal trauma (Ann Emerg Med 1987;16:653-658). In the trial simulations, patients were randomly assigned to the control and test groups, their outcomes were determined randomly according to the frequency of outcomes observed in the actual studies, and the simulated sequential studies were continued until conclusions were reached. Thousands of possible realizations of each trial were simulated; thus, the distribution of required patient numbers was determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗
PubMed1990

Phencyclidine.

Patients intoxicated with phencyclidine (PCP) present both diagnostic and management dilemmas. The clinical presentation ranges from coma to severe agitation and violence; disorientation, psychosis, catatonia and bizarre behavior can be seen. Patients are at-risk for significant medical complications such as rhabdomyolysis, seizures, and hyperthermia. This article reviews the effects and complications of PCP abuse and offers an approach to the management of these patients.

Ambulatory Care↗
PubMed1989

Effect of crystalloid infusion on hematocrit and intravascular volume in healthy, nonbleeding subjects.

We evaluated the effect of IV crystalloid administration on hematocrit in 28 healthy, nonbleeding volunteers. Normal saline boluses of 10, 20, and 30 mL/kg were delivered at a mean rate of 115 +/- 4 mL/min, followed by a continuous infusion of either 1 or 5 mL/kg/hr. Hematocrit values determined immediately after bolus infusion declined from baseline a mean +/- SEM of 4.5 +/- 0.6 (P less than .001), 6.1 +/- 0.4 (P less than .001) and 6.3 +/- 0.6 points (P less than .001) in the 10, 20, and 30 mL/kg groups, respectively. Twenty minutes into the maintenance infusion, hematocrits had risen 1.5 +/- 0.8 (P = .03), 2.4 +/- 0.4 (P = .004) and 2.3 +/- 0.7 points (P = .005) when compared with post-bolus hematocrits in the 10, 20, and 30 mL/kg groups, respectively. These data show that in healthy, nonbleeding subjects, crystalloid infusion may cause significant changes in hematocrit. Calculations reveal that approximately 60% of infused saline, when delivered as a bolus, will diffuse from the intravascular space within 20 minutes of administration.

Adult↗
PubMed1988

Delayed hemiparesis following nonpenetrating carotid artery trauma.

A 21-year-old man developed transient, recurring right arm and leg weakness 2 weeks after a motorcycle accident. He ultimately proved to have an intimal tear and thrombosis of the left internal carotid artery with transient cerebral ischemia due to distal emboli. Neurologic deficits eventually resolved after anticoagulation and balloon occlusion of the vessel. The differential diagnosis of the patient's presentation is discussed, and the topic of nonpenetrating trauma of the carotid artery is reviewed, with special attention to mechanism of injury and clinical presentation.

Accidents↗
PubMed1988

Conventional and right precordial ECGs, creatine kinase, and radionuclide angiography in post-traumatic ventricular dysfunction.

Right ventricular infarction due to ischemic heart disease can be diagnosed by a right precordial electrogram or by first-pass radionuclide angiography (FPRNA). Prior FPRNA studies have shown that cardiac dysfunction after blunt chest trauma (myocardial contusion) is most often due to right ventricular dysfunction. We hypothesized that right ventricular dysfunction due to ischemic heart disease and myocardial contusion should produce similar ECG changes due to myocyte disruption. The purpose of our study was to evaluate the diagnostic value of the right precordial electrogram in suspected cardiac contusion. Thirty-five patients with suspected myocardial contusion based on mechanism of injury/clinical findings and no history of clinical heart disease were enrolled prospectively. All patients had conventional ECG, right precordial electrogram, and FPRNA studies. Twenty patients had normal cardiac scans (group 1); percentage of myocardial creatine kinase (CK-MB) was measured in 12 of these patients and was less than 5% in 11. Fifteen patients had abnormal cardiac scans (wall motion abnormality and/or decreased right ventricular ejection fraction) (mean, 34% +/- 7% [SD]; normal, greater than 40%) (group 2); percentage of CK-MB was measured in 13 of 15 patients and was less than 5% in all 13. Conventional ECGs and right precordial electrograms in all patients were analyzed for differences in heart rate, PR interval, QRS duration, corrected QT interval, and the axis of the frontal and horizontal plane QRS complex and ST segment. There were no significant differences between group 1 and group 2 patients. No patient with myocardial contusion diagnosed by FPRNA had elevated ST segments in V4R through V6R or a percentage CK-MB of more than 5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Electrocardiographic criteria for tricyclic antidepressant cardiotoxicity.

To determine if electrocardiographic findings characterize tricyclic antidepressant (TCA) overdose and cardiotoxicity, 25 patients suspected of taking an overdose of TCA were studied. Toxicologic assays for a TCA were positive in 11 patients (+TCA, n = 11). Toxicologic study results for a TCA were negative in 14 patients (-TCA, control subjects). Patients with positive TCA results (+TCA) had a significantly greater heart rate (117 +/- 23 vs 100 +/- 22 beats/min, p less than 0.05), QRS duration (103 +/- 15 vs 87 +/- 10 ms, p less than 0.005) and corrected QT interval (449 +/- 38 vs 418 +/- 36 ms, p less than 0.05) than control patients (-TCA) on admission. Patients with positive TCA results also had a more rightward terminal 40-ms frontal plane QRS vector (195 +/- 51 degrees vs 54 +/- 64 degrees, p less than 0.001) than control patients. This observation has not been previously reported. A terminal QRS vector of 130 degrees to 270 degrees accurately discriminated between -TCA and +TCA patients (positive and negative predictive value = 1.00). Counterclockwise rotation (normalization) of the terminal frontal plane QRS vector was noted in +TCA patients during hospitalization. All +TCA patients had a sinus tachycardia, a corrected QT interval 418 ms or longer, and a terminal QRS vector between 130 degrees and 270 degrees. Using these values as selection criteria, a computer-aided search of 15,064 electrocardiograms (ECGs) recorded in our emergency department was performed. The likelihood of encountering such an electrocardiographic pattern in this population was 1.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Therapeutic and toxic effects of digitalis: William Withering, 1785.

William Withering's classic description of the effects of digitalis was published in 1785. Although he was largely unaware of the drug's cardiac effects, he successfully treated many patients with congestive heart failure. He also recorded many striking examples of digitalis toxicity. This review highlights Withering's experience with "the foxglove," and summarizes modern concepts of digitalis efficacy and toxicity.

Adult↗
PubMed1986

NMB usage survey.

Explore the source record for details and available documents.

California↗
PubMed1985

Aortoenteric fistula.

A fistula between the aorta and the gastrointestinal (GI) tract is a relatively uncommon and often lethal cause of GI bleeding. This report describes a patient with massive upper GI bleeding due to an aortoduodenal fistula. Such fistulae arise because of a combination of mechanical factors and local infection; the varied clinical presentations can be explained by the pathogenesis of the disease entity. These clinical presentations are reviewed, and a suggested approach to the diagnosis and management is presented.

Aged↗
PubMed1985

Oleander tea: herbal draught of death.

A woman died after drinking herbal tea prepared from oleander (Nerium oleander) leaves. This case demonstrates the cross-reactivity between the cardiac glycosides in oleander and the digoxin radioimmunoassay. Digoxin-specific Fab antibody fragments have not been used in oleander poisoning, but these might prove to be lifesaving. Treatment of oleander toxicity is aimed at controlling arrhythmias and hyperkalemia; inactivation of the Na-K ATPase pump, however, can make treatment difficult.

Adult↗
PubMedDate not supplied

Falsely elevated salicylate levels due to diflunisal overdose.

A 33-year-old man ingested 14 g of diflunisal (Dolobid, a NSAID), 3 propoxyphene-acetaminophen tablets, and ethanol. Although salicylate ingestion was specifically denied, toxicology screening revealed markedly elevated salicylate levels (176 mg/dL, 100 mg/dL, 41 mg/dL at 4 1/2, 10 and 24 hours postingestion). Blood ethanol level was 450 mg/dL. There was no respiratory alkalosis, metabolic acidosis, or increased anion gap to suggest salicylate toxicity. The patient recovered fully. Comparison testing of the salicylate assay technique used in the case (TDx fluorescence polarization immunoassay) and another commonly used technique (Trinder colorimetric assay) revealed marked cross-reactivity between salicylate and diflunisal. Samples of known diflunisal concentration were tested using the TDx salicylate assay. Percent cross-reactivity [(reported salicylate concentration/actual diflunisal concentration) x 100] was found to be 130 to 152.8% over the concentration range tested. Cross-reactivity between diflunisal and salicylate using the Trinder colorimetric assay was 20 to 52.5% over the concentration range tested. Diflunisal is not metabolized to salicylate and thus this cross-reactivity represents a significant drug-laboratory interaction. Salicylate levels measured by these methods appear to be unreliable when diflunisal is present.

Adult↗
PubMedDate not supplied

Aortoenteric fistula in a 21-year-old.

We present the case of a 21-year-old male with recurrent, severe gastrointestinal hemorrhage, who eventually proved to have an aortoduodenal fistula. The fistula arose from an aortic repair done after a stab wound four years previously. The diagnosis of aortoenteric fistula was not initially suspected because of the patient's age, inability to provide details of his previous surgery, and false-negative endoscopic and radiologic studies. We believe that this is the youngest reported patient who developed an aortoenteric fistula after aortic surgery. The presence of an aortoenteric fistula should be suspected in any patient with a GI bleed and previous aortic surgery, regardless of the patient's age.

Adult↗
PubMedDate not supplied

Statistical concepts and methods for the reader of clinical studies in emergency medicine.

An understanding of statistical concepts and methods is essential for the clinician who wishes to interpret the results of clinical studies. In this article the concepts of descriptive statistics, classical hypothesis testing, P values, a priori information, and Type I and Type II errors are discussed with examples to illustrate their application to the interpretation of clinical trials. In addition, descriptions of Student's t test, the chi-squared test, Fisher's exact test, the rank sum test, and sequential methods are given.

Bias↗
PubMedDate not supplied

Improvement of cardiac conduction after hyperventilation in tricyclic antidepressant overdose.

Three patients wtih severe cardiotoxicity secondary to tricyclic antidepressant (TCA) overdosage were treated with induced mechanical hyperventilation. All three demonstrated marked QRS narrowing, reflecting improved intracardiac conduction, after hyperventilation therapy. Such therapy may help to prevent or abolish ventricular dysrhythmias, often a feature of life-threatening TCA overdoses.

Adult↗