Anesthesiology
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Comparative Study
Comparison of an Updated Risk Stratification Index to Hierarchical Condition Categories.
The Risk Stratification Index and the Hierarchical Condition Categories model baseline risk using comorbidities and procedures. The Hierarchical Condition categories are rederived yearly, whereas the Risk Stratification Index has not been rederived since 2010. The two models have yet to be directly compared. The authors thus rederived the Risk Stratification Index using recent data and compared their results to contemporaneous Hierarchical Condition Categories. ⋯ Risk Stratification discrimination and minimum-variance predictions make it superior to Hierarchical Condition Categories. The Risk Stratification Index provides a solid basis for care-quality metrics and for provider comparisons.
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The use of venovenous extracorporeal membrane oxygenation is increasing worldwide. These patients often require noncardiac surgery. In the perioperative period, preoperative assessment, patient transport, choice of anesthetic type, drug dosing, patient monitoring, and intraoperative and postoperative management of common patient problems will be impacted. ⋯ Treatments of these conditions often require both manipulation of extracorporeal membrane oxygenation settings and physiologic interventions. Perioperative management of anticoagulation, as well as thresholds to transfuse blood products, remain highly controversial and must take into account the specific procedure, extracorporeal membrane oxygenation circuit function, and patient comorbidities. We will review the physiologic management of the patient requiring surgery while on venovenous extracorporeal membrane oxygenation.
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Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure-flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins. ⋯ The risk of right ventricular ischemia is also heightened during chronic elevations in right ventricular afterload because microvascular growth fails to match myocyte hypertrophy and because microvascular dysfunction is present. The right coronary circulation is more sensitive than the left to α-adrenergic-mediated constriction, which may contribute to its greater propensity for coronary vasospasm. This characteristic of the right coronary circulation may increase its vulnerability to coronary vasoconstriction and impaired right ventricular perfusion during administration of α-adrenergic receptor agonists.
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Assessment of clinical competence is essential for residency programs and should be guided by valid, reliable measurements. We implemented Baker's Z-score system, which produces measures of traditional core competency assessments and clinical performance summative scores. Our goal was to validate use of summative scores and estimate the number of evaluations needed for reliable measures. ⋯ The Baker system produced moderately reliable measures at our institution, suggesting that it may be generalizable to other training programs. Raw absolute scores required few assessment occasions to achieve 90% reliable measurements.