Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2015
ReviewClinical Research Methodology 1: Study Designs and Methodologic Sources of Error.
Clinical research can be categorized by the timing of data collection: retrospective or prospective. Clinical research also can be categorized by study design. ⋯ Comparative clinical trials are prospective cohort studies that compare treatments assigned to patients by the researchers. Most errors in clinical research findings arise from 5 largely distinguishable classes of methodologic problems: selection bias, confounding, measurement bias, reverse causation, and excessive chance variation.
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Anesthesia and analgesia · Oct 2015
ReviewClinical Research Methodology 3: Randomized Controlled Trials.
Randomized assignment of treatment excludes reverse causation and selection bias and, in sufficiently large studies, effectively prevents confounding. Well-implemented blinding prevents measurement bias. Studies that include these protections are called randomized, blinded clinical trials and, when conducted with sufficient numbers of patients, provide the most valid results. Although conceptually straightforward, design of clinical trials requires thoughtful trade-offs among competing approaches-all of which influence the number of patients required, enrollment time, internal and external validity, ability to evaluate interactions among treatments, and cost.
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Anesthesia and analgesia · Oct 2015
ReviewClinical Research Methodology 2: Observational Clinical Research.
Case-control and cohort studies are invaluable research tools and provide the strongest feasible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. ⋯ Causality-the most clinically useful relation between exposure and outcome-can rarely be definitively determined from observational studies because intentional, controlled manipulations of exposures are not involved. In this article, we review several types of observational clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects.
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Anesthesia and analgesia · Oct 2015
A Multimodal Intervention Improves Post-Anesthesia Care Unit Handovers.
Failures of communication are a major contributor to perioperative adverse events. Transitions of care may be particularly vulnerable. We sought to improve postoperative handovers. ⋯ A multimodal intervention substantially improved interprofessional PACU handovers, including those by clinicians who had not undergone formal simulation training. An effect appeared to be present >3 years later.
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Anesthesia and analgesia · Oct 2015
Comparative StudyMajor Upper Abdominal Surgery Alters the Calibration of Bioreactance Cardiac Output Readings, the NICOM, When Comparisons Are Made Against Suprasternal and Esophageal Doppler Intraoperatively.
Minimally invasive continuous cardiac output measurements are recommended for use during anesthesia to guide fluid therapy, but such measurements must trend changes reliably. The NICOM Cheetah, a BioReactance monitor, is being recommended for intraoperative use. To validate its use, Doppler methods, suprasternal USCOM and esophageal CardioQ, were used in tandem to provide reliable estimates of changing trends in cardiac output. Preliminary comparisons showed that upper abdominal surgical interventions caused shifts in the calibration of the NICOM. The purpose of this study was to confirm and measure these calibration shifts. ⋯ Doppler monitoring used in tandem provided valid trend lines of cardiac output changes against which NICOM readings could be compared. Intraoperatively, the NICOM was shown to track changes in cardiac output reliably in most circumstances. However, surgical interventions to the upper abdomen caused shifts in readings by >1 L/min/m, and the direction of the shifts was unpredictable. Anesthesiologists need to be aware of these calibration shifts and anticipate their occurrence, whenever the NICOM is used intraoperatively.