Anesthesiology
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Serial invasive and noninvasive (systolic time interval) measurements of left ventricular performance were obtained in six healthy volunteers during general anesthesia employing the following sequence: thiopental induction, succinylcholine (prior to endotracheal intubation), and halothane--100 per cent oxygen at 1.25 and 1.75 MAC. Heart rate (HR), mean pulmonary arterial "wedge" pressure (PAW) and mean systemic arterial pressure (MAP) were measured continuously; cardiac index and systolic time intervals (STI's) were measured during each intervention. At both levels of halothane, MAP and stroke work index decreased (both P less than 0.02), while HR and systemic vascular resistance did not change. ⋯ This intervention resulted in a greater depression of cardiac performance than that observed at 1.75 MAC halothane alone. Although alterations in STI's were directionally similar to changes observed in invasive hemodynamic measurements, STI's were sensitive to acute alternations in loading conditions. It is concluded that the levels of halothane commonly employed for general anesthesia significantly depress left ventricular performance in normal subjects, as evidenced by abnormal responses to alterations in preload and afterload, and that STI's should not be employed for routine measurement of left ventricular performance during anesthesia unless both the afterload and the preload on the myocardium are known.
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The 1970 geographical distributions of total anesthesia manpower, anesthesiologists, and nurse anesthetists by state were analyzed by multiple regression to account for their unevenness. Independent variables included factors relating to prior professional contact in the state, professional satisfaction, practice income, demand for services, and environment. The distribution of training programs accounted for 41 per cent of the variance in the distribution of total manpower, but 55 per cent was explained by the number of operations, location of nurse anesthesia schools, and proportion of total state employment in service occupations (a proxy for the availability of consumer services). ⋯ The location of residency programs (or positions) was a better predictor for the anesthesiologists' location than medical schools or factors characterizing the demand for services. The distribution of nurse anesthetists, hospital cost per day (considered a proxy for a satisfying professional life and for regionalization of services), and residency programs explained 81 per cent of the variance in the anesthesiologists' distribution. Although the regression predicts that increasing the number of residency programs in an underserved state should be associated with an increase the number of anesthesiologists, such a policy may be infeasible dur to pending federal health manpower legislation unless matched by decreasing a greater number of programs in relatively oversupplied states.
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Comparative Study Clinical Trial
Comparison of compounds used for intradermal anesthesia.