Operating room clinicians' ratings of workload: a vignette simulation study.

Objectives: Increased clinician workload is associated with medical errors and patient harm. The Quality and Workload Assessment Tool (QWAT) measures anticipated (pre-case) and perceived (post-case) clinical workload during actual surgical procedures using ratings of individual and team case difficulty from every operating room (OR) team member. The purpose of this study was to examine the QWAT ratings of OR clinicians who were not present in the OR but who read vignettes compiled from actual case documentation to assess interrater reliability and agreement with ratings made by clinicians involved in the actual cases.

Rank-based estimate of four-parameter logistic model.

During drug development, the calculation of inhibitory concentration that results in a response of 50% (IC50) is performed thousands of times every day. The nonlinear model most often used to perform this calculation is a four-parameter logistic, suitably parameterized to estimate the IC50 directly. When performing these calculations in a high-throughput mode, each and every curve cannot be studied in detail, and outliers in the responses are a common problem.

Automated identification of postoperative complications within an electronic medical record using natural language processing.

Context: Currently most automated methods to identify patient safety occurrences rely on administrative data codes; however, free-text searches of electronic medical records could represent an additional surveillance approach.

Objective: To evaluate a natural language processing search-approach to identify postoperative surgical complications within a comprehensive electronic medical record.

Design, Setting, And Patients: Cross-sectional study involving 2974 patients undergoing inpatient surgical procedures at 6 Veterans Health Administration (VHA) medical centers from 1999 to 2006.

Reference regions for beat-to-beat ECG data.

The QT interval is regarded as an important biomarker for the assessment of arrhythmia liability, and evidence of QT prolongation has led to the withdrawal and relabeling of numerous compounds. Traditional methods of assessing QT prolongation correct the QT interval for the length of the RR interval (which varies inversely with heart-rate) in a variety of ways. These methods often disagree with each other and do not take into account changes in autonomic state.

Analyses of dynamic beat-to-beat QT-TQ interval (ECG restitution) changes in humans under normal sinus rhythm and prior to an event of torsades de pointes during QT prolongation caused by sotalol.

Background: Restitution through intracardiac pacing has been used to assess arrhythmia vulnerability. We examined whether analyses of sequential beat-to-beat QT and TQ interval measures can be used to quantify ECG restitution changes under normal sinus rhythm.

Methods: The QT, R-R and TQ intervals were examined 22.

Electrical alternans and hemodynamics in the anesthetized guinea pig can discriminate the cardiac safety of antidepressants.

Introduction: The arrhythmogenic risk of fluoxetine, citalopram, and venlafaxine were evaluated through preclinical assays measuring hERG, blood pressure and electrical alternans over their respective clinical unbound concentration ranges.

Methods: Anesthetized guinea pigs were instrumented with jugular and carotid cannulae for drug infusion and blood pressure monitoring respectively; a thoracotomy was performed for placement of a monophasic action potential probe on the left ventricle and for placement of pacing wires on the left ventricular apex. Drugs were infused as a 5-min loading dose immediately followed by a 10-min maintenance dose to achieve clinically relevant plasma concentrations; blood samples were taken at the end of each maintenance dose.

Differentiation of arrhythmia risk of the antibacterials moxifloxacin, erythromycin, and telithromycin based on analysis of monophasic action potential duration alternans and cardiac instability.

Antibacterial drugs are known to have varying degrees of cardiovascular liability associated with QT prolongation that can lead to the ventricular arrhythmia torsade de pointes. The purpose of these studies was to compare the assessment for the arrhythmogenic risk of moxifloxacin, erythromycin, and telithromycin. Each drug caused dose-dependent inhibition of the rapidly activating delayed rectifier potassium current encoded by the human ether-á-go-go-related gene (hERG) with IC20 concentrations of 31 microM (moxifloxacin), 21 microM (erythromycin), and 11 microM (telithromycin).

QT prolongation modifies dynamic restitution and hysteresis of the beat-to-beat QT-TQ interval relationship during normal sinus rhythm under varying states of repolarization.

The analysis of cardiac electrical restitution (the relationship between an action potential duration and its preceding diastolic interval) has been used to predict arrhythmia liability. However, the procedure to measure restitution is invasive and disrupts normal physiological autonomic balance. Dynamic analysis of sequential beat-to-beat ECG data was used to study restitution under normal sinus rhythm and to quantify changes in temporal hysteresis with heart rate acceleration/deceleration during QT prolongation.

Influence of molecular flexibility and polar surface area metrics on oral bioavailability in the rat.

The relationship of rotatable bond count (N(rot)) and polar surface area (PSA) with oral bioavailability in rats was examined for 434 Pharmacia compounds and compared with an earlier report from Veber et al. (J. Med.

Dynamic beat-to-beat modeling of the QT-RR interval relationship: analysis of QT prolongation during alterations of autonomic state versus human ether a-go-go-related gene inhibition.

Methods to correct the QT interval for heart rate are often in disagreement and may be further confounded by changes in autonomic state. This can be problematic when trying to distinguish the changes in QT interval by either drug-induced delayed repolarization or from autonomic-mediated physiological responses. Assessment of the canine dynamic QT-RR interval relationship was visualized by novel programming of the dynamic beat-to-beat confluence of data or "clouds".