Paradoxical scintigraphic pattern in regions with myocardial necrosis on myocardial perfusion gated SPECT with 99mTc-tetrofosmin

Objectives

To assess the significance of a paradoxical pattern (PP) (greater tracer uptake during stress than at rest) on gated myocardial perfusion SPECT in myocardial regions with myocardial necrosis.

Methods

A review of 1,764 consecutive stress-rest myocardial perfusion SPECT studies in patients with prior myocardial infarction (MI) was conducted. Of these, 117 patients (6.6%) with a PP corresponding to a region with myocardial necrosis were identified. An assessment of perfusion, contractility, wall thickening, scintigraphic criteria for viability, and the characteristics of the culprit artery in regions with a PP was performed.

Results

Of the 160 regions with necrosis, 125 (75%) had a PP: 67 in the anterior region and 58 in the inferior-lateral region. In the PP group, the average tracer activity of defects during stress was significantly higher than at rest (P?<?.0001). Ninety-three (86.6%) out of 110 PP segments without scintigraphic criteria of viability at rest met viability criteria on stress imaging. The artery supplying regions with a PP was patent in 88% of cases. In the remaining patients it was occluded, although collateral circulation was always present.

Conclusions

In scintigraphic segments corresponding to regions with infarction and PP, a mixture of viable and well perfused myocardium was observed. In most cases, the vessel that supplied the region with PP was either patent, or when the artery was occluded, there was evident collateral circulation.     

Monitoring technique affects measurement of recovery from succinylcholine

To compare recovery time from neuromuscular blockade after the administration of a single intravenous bolus of succinylcholine (1 mg/kg), we measured, both mechanically and electromyographically, the evoked twitch responses in the hand muscles of 10 patients. Electromyographic data were obtained, electronically integrated, and recorded by a newly available clinical monitoring device. Using both the mechanical and the electromyographic devices, we recorded the times for first return of twitch, as well as for 25% and 75% recovery of twitch height compared with prerelaxant twitch baseline values and compared the values by calculating least-squares regression lines. Times given by the electromyographic device for these measures of returning neuromuscular function were notably longer than those given by the mechanical evoked force monitor. No such findings have been reported in previous studies that compared these two techniques for monitoring of muscle recovery from nondepolarizing relaxants. The specific reasons for the differences found in this study are unknown.Presented in part at the annual meeting of the American Society of Anesthesiologists, Oct 12–16, 1985, San Francisco, CA. The authors thank Danae Powers, MD, for providing statistical advice.     

An Emergency Department–based Vaccination Program: Overcoming the Barriers for Adults at High Risk for Vaccine-preventable Diseases

Background: More than 10% of the population visit emergency departments (ED) every year. Many of these patients are not up‐to‐date on routine vaccinations that could prevent future illnesses. The ED could significantly impact these vaccination trends. Objectives: This study was a feasibility study to determine whether patients would be amenable to an ED‐based program that provided appropriate immunizations when they were at high risk for these diseases. In addition, the authors sought to identify barriers that predict high‐risk patients who did not receive immunizations before ED presentation and to identify barriers that predict those high‐risk unvaccinated patients who are unwilling to receive vaccinations when offered in the ED. Methods: This study was a prospective cross‐sectional study of all patients arriving in the ED at one inner‐city trauma center between 10 am and 10 pm over the course of a three‐week intervention period. The subjects completed a survey that included information about their risk of influenza (flu) and pneumococcal disease, their immunization history, and their perceptions of their need for immunization. Demographic information collected included insurance status, age, gender, and primary language. All high‐risk patients who were not current with their immunizations were offered vaccination. The primary outcome was improvement in vaccination coverage based on an ED surveillance and treatment system for vaccinations. The secondary outcomes were barriers to successful vaccination before ED presentation and barriers to acceptance of vaccination in the ED. Results were compared using chi‐square test and confidence interval analysis. Characteristics of barriers to immunization were determined using a logistic regression model. A p‐value < 0.05 was considered significant. Results: A total of 674 subjects were entered into the study. Vaccination of subjects at high risk for flu increased significantly from 16% before to 83% after ED evaluation and treatment, and vaccination of subjects at high risk for pneumococcal disease increased significantly from 18% before to 84% after ED evaluation and treatment. Significant barriers to vaccination before ED presentation were lack of insurance (odds ratio [OR] = 0.31 for flu, 0.22 for pneumococcal disease), age younger than 50 years (OR = 0.18 for flu, 0.24 for pneumococcal disease), and no perceived need for vaccination (OR = 0.07 for flu). The sole significant barrier to vaccine administration in the ED was perceived need for vaccination (OR = 0.32 for flu). Conclusions: An ED‐based vaccination program is both feasible and successful. Other than a shortage of vaccine, the only ED barrier to vaccination (perceived need) might be overcome with patient education.     

Obese Patients with Abdominal Pain Presenting to the Emergency Department Do Not Require More Time or Resources for Evaluation Than Nonobese Patients

Objectives: The authors describe the evaluation of obese and nonobese adult patients with abdominal pain presenting to an emergency department (ED). The hypothesis was that more ED and hospital resources are used to evaluate and treat obese patients. Methods: A prospective observational study of obese (n= 98; body mass index ≥30 kg/m²) and nonobese (n= 176; body mass index < 30 kg/m²) adults presenting to the ED with abdominal pain was performed. ED length of stay (LOS) was the primary outcome. Secondary outcomes included use of laboratory tests, computed tomography, and ultrasonography, and rates of consultations, operations, and admissions. ED diagnoses were compared between the two groups. Results: Obese patients were older (41.9 vs. 38.3 years; p = 0.027) and more often female (69% vs. 51%; p = 0.003) than nonobese patients. There were no significant differences between obese and nonobese patients in either the primary or the secondary outcome measures. Obese patients were similar to nonobese patients in regard to LOS (457 vs. 486 minutes), laboratory studies (3.2 vs. 2.9 tests), abdominopelvic computed tomographic scans (30% vs. 31%), and abdominal ultrasounds (16% vs. 13%). Obese and nonobese patients were also similar in their rates of consultations (27% vs. 31%), operations (14% vs. 12%), and admissions (18% vs. 24%). No difference was found for LOS between obese and nonobese patients as evaluated by the Wilcoxon rank‐sum test (p = 0.81). Logistic regression analysis controlling for baseline characteristics revealed no significant differences between obese and nonobese patients for secondary outcome variables. ED diagnoses for obese and nonobese patients were similar except that genitourinary diagnoses were less common in obese patients (8% vs. 21%; p = 0.01). Conclusions: In contradiction to the hypothesis, the results suggest that LOS and ED resource use in obese patients with abdominal pain are not increased when compared with nonobese patients.     

Viral respiratory infections in elderly patients and patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) and elderly individuals are prone to the development of significant lower respiratory tract symptoms from colds caused by viral respiratory pathogens. Longitudinal surveillance studies conducted to assess the impact of viral respiratory tract pathogens on morbidity and mortality in each of these at-risk populations demonstrate that there is a substantial burden of disease from viral respiratory infection (VRI), including rhinovirus infections, with respect to utilization of health-care resources. Despite a similar rate of occurrence of VRI among subjects with COPD and the control group, a cohort with moderate to severe COPD had a 2-fold increase in medical resource utilization, including clinician visits, emergency center visits, and hospitalizations. In surveillance studies of respiratory viruses in the elderly, regular seasonal infections with rhinoviruses cause substantial morbidity, which has been largely underappreciated and underreported.     

Structure-activity relationships of aminocoumarin-type gyrase and topoisomerase IV inhibitors obtained by combinatorial biosynthesis

Novobiocin and clorobiocin are gyrase inhibitors produced by Streptomyces strains. Structurally, the two compounds differ only by substitution at two positions: CH3 versus Cl at position 8' of the aminocoumarin ring and carbamoyl versus 5-methyl-pyrrol-2-carbonyl (MePC) at the 3"-OH of noviose. Using genetic engineering, we generated a series of analogs carrying H, CH3, or Cl at 8' and H, carbamoyl, or MePC at 3"-OH. Comparison of the gyrase inhibitory activities of all nine structural permutations confirmed that acylation of 3"-OH is essential for activity, with MePC being more effective than carbamoyl. Substitution at 8' further enhanced activity, but the effect of CH3 or Cl depended on the nature of the acyl group at 3": in the presence of carbamoyl at 3", CH3 resulted in higher activity; in the presence of MePC at 3", Cl resulted in higher activity. This suggests that the structures of both natural compounds are highly evolved for optimal interaction with gyrase. In a second series of experiments, clorobiocin derivatives with and without the methyl group at 4"-OH of noviose, and with different positions of the MePC group of noviose, were tested. Again clorobiocin was superior to all of its analogs. The activities of all compounds were also tested against topoisomerase IV (topo IV). Clorobiocin stood out as a remarkably effective topo IV inhibitor. The relative activities of the different compounds toward topo IV showed a pattern similar to that of the relative gyrase-inhibitory activities. This is the first report of a systematic evaluation of a series of aminocoumarins against both gyrase and topo IV. The results give further insight into the structure-activity relationships of aminocoumarin antibiotics.     

Versatile,Reusable, and Inexpensive Ultrasound Phantom Procedural Trainers

We have constructed simple and inexpensive models for ultrasound‐guided procedural training using synthetic ballistic gelatin. These models are durable, leak resistant, and able to be shaped to fit a variety of simulation scenarios to teach procedures. They provide realistic tactile and sonographic training for our learners in a safe, idealized setting.