Biomedical subjects

William Shannon

Publications and source records attributed to William Shannon.

4 recordsLinked to original sources

PubMed2003

The influence of infection on hospital mortality for patients requiring > 48 h of intensive care.

OBJECTIVE: To determine the influence of microbiologically confirmed infection on hospital mortality among patients requiring intensive care for > 48 h. DESIGN: Prospective cohort study. SETTING: Medical ICU of the Barnes-Jewish Hospital, an urban teaching hospital. PATIENTS: A total of 893 patients requiring intensive care for > 48 h. INTERVENTIONS: Prospective patient surveillance and data collection. MEASUREMENTS AND MAIN RESULTS: Three hundred seventy-two patients (41.7%) requiring intensive care for > 48 h had a microbiologically confirmed infection. Only six patients (0.7% [1.6% of patients with microbiologically confirmed infections]) received inadequate antimicrobial therapy during the first 24 h of treatment, and 248 patients (27.8%) died during hospitalization. Compared to hospital survivors, hospital nonsurvivors were significantly more likely to have a microbiologically confirmed infection (53.2% vs 37.2%, respectively; p < 0.001) and to develop severe sepsis (45.6% vs 28.7%, respectively; p < 0.001). Cirrhosis and the requirement for vasopressors were the only variables identified by multiple logistic regression analysis as independent risk factors for hospital mortality in all patient groupings of severity of illness. Multiple logistic regression analysis also demonstrated that underlying malignancy (adjusted odds ratio [AOR], 1.98; 95% CI, 1.55 to 2.53), chronic renal insufficiency (AOR, 1.57; 95% CI, 1.31 to 1.87), cirrhosis (AOR, 1.94; 95% CI, 1.48 to 2.53), temperature > 38.3 degrees C (AOR, 1.72; 95% CI, 1.47 to 2.02), severe sepsis (AOR, 2.78; 95% CI, 1.94 to 3.98), positive culture for vancomycin-resistant enterococci (AOR, 1.78; 95% CI, 1.51 to 2.09), and the presence of multiple infections (AOR, 1.65; 95% CI, 1.28 to 2.14) were independently associated with the requirement for therapy with vasopressors. CONCLUSIONS: Microbiologically confirmed infections are common among patients requiring medical intensive care for > 48 h. Despite the administration of adequate antimicrobial therapy, microbiologically confirmed infections appear to be an important cause of hemodynamic instability and increased hospital mortality. These data suggest that clinical efforts aimed at the prevention of infections and improvements in the medical management of patients with severe infections, especially those associated with hemodynamic instability and the need for vasopressors, are required to achieve further improvements in patient outcomes.

Adolescent↗

PubMed2003

Analyzing microarray data using cluster analysis.

As pharmacogenetics researchers gather more detailed and complex data on gene polymorphisms that effect drug metabolizing enzymes, drug target receptors and drug transporters, they will need access to advanced statistical tools to mine that data. These tools include approaches from classical biostatistics, such as logistic regression or linear discriminant analysis, and supervised learning methods from computer science, such as support vector machines and artificial neural networks. In this review, we present an overview of another class of models, cluster analysis, which will likely be less familiar to pharmacogenetics researchers. Cluster analysis is used to analyze data that is not a priori known to contain any specific subgroups. The goal is to use the data itself to identify meaningful or informative subgroups. Specifically, we will focus on demonstrating the use of distance-based methods of hierarchical clustering to analyze gene expression data.

Cluster Analysis↗

PubMed2002

Deep vein thrombosis during prolonged mechanical ventilation despite prophylaxis.

OBJECTIVE: To determine the prevalence of deep vein thrombosis (DVT) among patients requiring prolonged mechanical ventilation in the intensive care unit. DESIGN: Prospective cohort study. SETTING: Medical intensive care unit of a university-affiliated urban teaching hospital. PATIENTS: Patients requiring mechanical ventilation for >7 days. INTERVENTIONS: All patients admitted to the medical intensive care unit requiring prolonged mechanical ventilation underwent duplex ultrasonography of their lower extremities and upper extremities every 7 days. The main outcome identified was the presence of DVT. Secondary outcomes included hospital mortality, hospital and intensive care unit lengths of stay, and the occurrence of pulmonary embolism. MEASUREMENTS AND MAIN RESULTS: A total of 110 patients requiring mechanical ventilation for >7 days were enrolled. Prophylaxis against DVT was employed in 110 of the patients (100%). A total of 26 patients (23.6%) developed DVT. Patients with DVT were statistically more likely to have underlying malignancy (30.8% vs. 8.3%; p =.004) and longer durations of central venous catheterization (26.9 +/- 22.2 days vs. 14.5 +/- 12.1 days; p =.024) compared with patients without DVT. There were no statistically significant differences in hospital mortality or lengths of stay in the hospital and intensive care unit for patients with and without DVT. Patients documented to have DVT by using duplex ultrasonography had a statistically greater frequency of subsequent pulmonary embolism during their hospitalization (11.5% vs. 0.0%; p =.012). CONCLUSION: The occurrence of DVT is common among patients requiring prolonged mechanical ventilation in the intensive care unit setting despite the use of prophylaxis measures. These data suggest that alternative strategies for the prevention of DVT should be evaluated. Additionally, early detection methods should be considered to reduce the potential morbidity associated with untreated DVT in this high-risk population.

Adult↗

PubMed2002

Limb dominance as a potential etiologic factor in noncontact anterior cruciate ligament tears.

A retrospective case series analysis of 80 patients (44 males and 36 females) who presented with acute, unilateral, noncontact anterior cruciate ligament (ACL) tears was performed. The role of limb dominance as a possible etiologic factor in noncontact ACL tears was investigated and the gender-specific relationship was determined. Patients were questioned about the nature of their injury and asked to list their preferred upper and lower extremities for writing, throwing, and kicking-activities previously used to define upper and lower extremity dominance. The relationships between limb dominance, side of injury, and gender were assessed. Mean patient age was 27.8 years. The left knee was involved in 54% of patients and the right knee in 46%. Eighty-nine percent of the study group identified themselves as right-hand dominant for writing, 91% were right-hand dominant for throwing, and 89% were right-leg dominant for kicking. Overall, there was no significant correlation between the side of injury and dominant limb for writing (P=.84), throwing (P=.68), or kicking (P=.99). There also was no significant gender effect on the relationship between limb dominance and side of injury (P=.65). Limited numbers precluded an analysis of specific limb-dominant sports activities as potential risk factors. The results of this pilot study suggest limb dominance is not a significant etiologic factor for noncontact ACL tears.

Adolescent↗