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Biomedical subjects

Brian J Barnes

Publications and source records attributed to Brian J Barnes.

7 recordsLinked to original sources
PubMed2006

Risk-stratified evaluation of amiodarone to prevent atrial fibrillation after cardiac surgery.

BACKGROUND: Amiodarone prophylaxis (AMP) reduces the prevalence of postoperative atrial fibrillation (POAF) after cardiac surgery. We investigated the impact of AMP on the frequency and duration of POAF, the intensive care unit and hospital length of stay, and its cost-effectiveness in a risk-stratified cohort. METHODS: A retrospective, observational analysis of 509 patients who underwent cardiac surgery in 2003 was performed. Data sources included The Society of Thoracic Surgeons national database; medical and medication administration records; and the activity-based cost data from our institution. Risk stratification for POAF was determined using a validated risk index. Cost-effectiveness was determined from the hospital's perspective. RESULTS: The mean patient age was 63 years, 27% were female, 80% underwent coronary artery bypass grafting, and 29% underwent valve surgery. When a risk-stratified evaluation was made, 50% of patients were at an elevated risk for having POAF develop. When compared with nonprophylaxed patients, those receiving AMP (59%) experienced less POAF (31% vs 22%; p = 0.027) and shorter durations of POAF (4.7 vs 2.7 days; p = 0.025). In the elevated-risk group, AMP clinically (but not significantly) reduced length of stay in the intensive care unit (101 vs 68 hours; p > 0.05) and post-procedural hospital length of stay (9.7 vs. 7.9 days, p > 0.05). In the elevated-risk group, AMP was robustly cost-effective in reducing POAF. CONCLUSIONS: Amiodarone prophylaxis reduced the prevalence and duration of POAF. Baseline risk for POAF was a major determinant of the overall cost-effectiveness of AMP. The greatest cost savings with AMP was seen in patients at an elevated risk for POAF. These findings suggest the need for risk stratification when prescribing AMP.

Amiodarone↗
PubMed2006

Osmol gap as a surrogate marker for serum propylene glycol concentrations in patients receiving lorazepam for sedation.

STUDY OBJECTIVES: To correlate serum propylene glycol concentration with osmol gap, serum lactate concentration, and amount of propylene glycol administered to mechanically ventilated patients receiving continuous infusions of lorazepam (80% propylene glycol by weight), and to characterize the prevalence of hyperosmolality and range of serum propylene glycol concentrations in this patient population. DESIGN: Prospective, controlled, observational study. SETTING: Adult surgical and cardiothoracic intensive care units (ICUs) of a 1200-bed, urban, tertiary care, teaching hospital. PATIENTS: Sixty-four consecutively enrolled intensive care patients requiring mechanical ventilation and pharmacologic sedation. INTERVENTION: Thirteen patients received continuous infusions of high-dose lorazepam (> or = 6 mg/hr) for a minimum of 36 hours, and 26 received continuous infusions of low-dose lorazepam (2-5.99 mg/hr) for 36 hours. Twenty-five control patients received sedatives that did not contain propylene glycol. MEASUREMENTS AND MAIN RESULTS: Serum propylene glycol and lactate concentrations, osmolality, and basic metabolic profiles were obtained 72-108 hours after ICU admission. Clinical data, drug administration, and severity of illness scores were recorded. Osmol gap and the amount of propylene glycol administered before serum sampling predicted propylene glycol concentrations (r(2)=0.692, p<0.05). Osmol gap alone also predicted serum propylene glycol concentrations (r(2)=0.532, p<0.05). Serum lactate concentrations did not correlate with serum propylene glycol concentrations. Unlike the low-dose and control patients, eight (62%) of 13 high-dose patients had osmol gaps above 10. All 13 high-dose patients had serum propylene glycol concentrations previously associated with toxicity. CONCLUSION: Osmol gap can be used as a surrogate marker for serum propylene glycol concentration. In critically ill patients receiving lorazepam for sedation, an osmol gap above 10 was associated with concentrations previously reported to cause toxicity.

Adolescent↗
PubMed2005

Nationwide antibiogram analysis using NCCLS M39-A guidelines.

Lack of standardization in antibiogram (ABGM) preparation (the overall profile of antimicrobial susceptibility results of a microbial species to a battery of antimicrobial agents) has not been addressed until recently. The objective of this study was to analyze current antibiograms using the recently published NCCLS M39-A guidelines for preparation of antibiograms to identify areas for improvement in the reporting of antibiogram susceptibility data. Antibiograms from across the United States were obtained by various methods, including direct mailings, Internet searches, and professional contacts. Each ABGM collected was analyzed using prospectively defined elements from the M39-A guidelines. Additionally, seven quality indicators were also evaluated to look for the reporting of any atypical or inappropriate susceptibility data. The 209 antibiograms collected from 149 institutions showed at least 85% compliance to 5 of the 10 M39-A elements analyzed. Clinically relevant elements not met included annual analysis, duplicate isolate notation, and the exclusion of organisms with fewer than 10 isolates. As for the quality indicators evaluated, unexpected results included the 7% of antibiograms that reported <100% vancomycin susceptibility for Staphylococcus aureus, 24% that had inconsistent beta-lactam susceptibility for Staphylococcus aureus, 20% that reported <100% imipenem susceptibility for Escherichia coli, and 37% that reported >0% ampicillin susceptibility for Klebsiella pneumoniae. These findings suggest that antibiograms should be reviewed thoroughly by infectious disease specialists (physicians and pharmacists), clinical microbiologists, and infection control personnel for identification of abnormal findings prior to distribution.

Anti-Bacterial Agents↗
PubMed2004

Eplerenone: a selective aldosterone receptor antagonist for patients with heart failure.

OBJECTIVE: To evaluate the pharmacology, pharmacokinetics, safety, and clinical use of eplerenone in heart failure (HF). DATA SOURCES: English-language MEDLINE searches were performed from 1966 to May 2004. Key words included eplerenone, aldosterone receptor antagonist, heart failure, myocardial infarction, left-ventricular dysfunction, and cost-effectiveness. Additional references were identified from bibliographies of selected articles. STUDY SELECTION AND DATA EXTRACTION: Human trials evaluating the efficacy, safety, and cost-effectiveness of aldosterone receptor antagonists in HF were evaluated. DATA SYNTHESIS: Eplerenone is the first selective aldosterone receptor antagonist. The drug is indicated to improve the survival of stable patients with left-ventricular systolic dysfunction (ejection fraction <40%) and clinical evidence of HF following acute myocardial infarction. Efficacy and safety in this population have been demonstrated in a large, randomized clinical trial. Eplerenone is associated with severe and sometimes life-threatening hyperkalemia. Patients with reduced renal function and diabetes, as well as those on other drugs that increase potassium levels, are at highest risk. Eplerenone is metabolized by the cytochrome P450 system and may interact with drugs that interfere with this system. A major advantage of eplerenone over the nonselective aldosterone receptor antagonist spironolactone is lack of binding to progesterone and androgen receptors, which is associated with drug-induced gynecomastia, breast pain, and impotence. CONCLUSIONS: The addition of eplerenone to traditional HF therapy has been shown to reduce morbidity and mortality in patients who develop left-ventricular dysfunction after acute myocardial infarction. Eplerenone's selectivity reduces sex hormone-related adverse effects. Despite these benefits, the overall cost-effectiveness has yet to be determined.

Animals↗
PubMed2003

Enterobacter cloacae ventriculitis successfully treated with cefepime and gentamicin: case report and review of the literature.

A 55-year-old woman was found unresponsive and subsequently was diagnosed with a subarachnoid hemorrhage secondary to a right posterior communicating artery aneurysm. The development of hydrocephalus and decreased mental status necessitated placement of an intraventricular catheter; 18 days later she was diagnosed with Enterobacter cloacae ventriculitis. After treatment was begun with intravenous cefepime 2 g every 8 hours and intraventricular gentamicin 5 mg every 24 hours, the catheter was replaced. Cerebrospinal fluid (CSF) and plasma cefepime concentrations and a CSF trough gentamicin concentration were obtained. Intraventricular gentamicin was administered for 6 days and cefepime for 21 days; both clinical and microbiologic resolution of the ventriculitis occurred. The literature reports limited clinical experience with cefepime for the treatment of central nervous system infections in humans. This case report provides clinical evidence to support administration of intravenous cefepime in critically ill adult patients with Enterobacter ventriculitis. Because CSF is easily obtained from patients with intraventricular catheters, strong consideration should be given to monitoring CSF cefepime concentrations in concert with the minimum inhibitory concentration of the offending pathogen to help assure the efficacy of this approach to therapy.

Cefepime↗