Anesthesia and analgesia
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We determined the performance of the vaporizer of the ADU machine (Anesthesia Delivery Unit; Datex-Ohmeda, Helsinki, Finland). The effects of carrier gas composition (oxygen, oxygen/N(2)O mixture, and air) and fresh gas flow (0.2 to 10 L/min) on vaporizer performance were examined with variable concentrations of isoflurane, sevoflurane, and desflurane across the whole range of each vaporizer's output. In addition, the effects of sudden changes in fresh gas flow and carrier gas composition, back pressure, flushing, and tipping were assessed. Vaporizer output depended on fresh gas flow, carrier gas composition, dial settings, and the drug used. Vaporizer output remained within 10% of dial setting with fresh gas flows of 0.3-10 L/min for isoflurane, within 10% of dial setting with fresh gas flows of 0.5-5 L/min for sevoflurane, and within 13% of dial setting with fresh gas flows of 0.5 to 1 L/min for desflurane. Outside these fresh gas flow ranges, output deviated more. The effect of sudden changes in fresh gas flow or carrier gas composition, back pressure, flushing, and tipping was minimal. We conclude that the ADU vaporizer performs well under most clinical conditions. Despite a different design and the use of complex algorithms to improve accuracy, the same physical factors affecting the performance of conventional vaporizers also affect the ADU vaporizer. ⋯ The ADU vaporizer performs well under most clinical conditions. Despite a different design and the use of complex algorithms to improve accuracy, the same physical factors affecting the performance of conventional vaporizers also affect the ADU vaporizer.
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This article examines recent trends in the management of academic physician practice groups, and in particular the allocation of revenues and expenses to anesthesiology departments. The history of academic group practice is traced, beginning with the "corporate model," in which each department functioned in financial independence from the others. This evolved gradually into the "feudal system," in which departments were ostensibly independent, but paid variable and often large "assessments" to the central group. The final stage in this evolution is the "big bag," in which all clinical revenue is pooled by the central practice group, and then distributed by the group to departments or individuals according to some compensation plan formula. The advantages and disadvantages of each of these systems are discussed as they apply to anesthesiology departments. A productivity-based compensation plan formula under the big bag system is calculated for a typical anesthesiology department. This calculation shows that if the compensation formula is truly based on measured clinical productivity, anesthesiology departments may actually fare better under the big bag than under the feudal system. Finally, options for survival in the academic practice groups of the future are discussed. ⋯ The history, current status, and trends of finances in academic anesthesiology departments are reviewed. Knowledge of these issues will help departments develop funds allocation methods to ensure that they receive an appropriate share of their faculty practice group's clinical income.
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Anesthesia and analgesia · Aug 2001
The prevalence and predictive value of abnormal preoperative laboratory tests in elderly surgical patients.
Because data to determine which preoperative laboratory tests are important in elderly surgical patients are limited, we performed a prospective cohort study to evaluate the prevalence and predictive value of abnormal preoperative laboratory tests in consecutive patients > or =70 yr old who were undergoing noncardiac surgery. Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care were excluded. Preoperative risk factors and laboratory test results were measured and evaluated for their association with the occurrence of predefined in-hospital postoperative adverse outcomes. In 544 patients, the prevalence of preoperative electrolytes and platelet count abnormalities (<115 x10(9)/L) was small (0.5%-5%), and abnormal creatinine (>1.5 mg/dL), hemoglobin (<10 g/dL), and glucose (>200 mg/dL) values were 12%, 10%, and 7%, respectively. Univariate predictors for adverse outcome of abnormal sodium and creatinine were not as predictive as ASA classification and surgical risk. By multivariate logistic regression, only ASA classification (>II) (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.56-4.19; P < 0.001) and surgical risk (OR, 3.48; 95% CI, 2.31-5.23; P < 0.001) were significant independent predictors of postoperative adverse outcomes. The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated. ⋯ The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated.
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Anesthesia and analgesia · Aug 2001
The effect of intrathecal analgesia on the success of external cephalic version.
External cephalic version (ECV), the procedure whereby a fetus in the breech position is converted to vertex, is often performed to avoid an operative delivery. Potential benefits of epidural and spinal anesthesia for this procedure are controversial. Several previous studies have evaluated the use of epidural anesthesia with varying results. We sought to determine whether analgesia produced by subarachnoid sufentanil would safely improve the success of ECV. Patients who received subarachnoid analgesia (n = 20) were compared with those who did not (n = 15) in regard to success of ECV, level of pain during ECV, and satisfaction. ECV was successful in 21 patients (60%), with more frequent success in women who received spinal analgesia as compared with those who did not (80% vs 33%, respectively; P = 0.005). Patients who received spinals also reported smaller pain scores and were more satisfied with ECV. None of the women who received spinal analgesia developed a postdural puncture headache, and the only case of fetal bradycardia occurred in a patient who did not receive spinal analgesia. More profound patient comfort after spinal analgesia may have permitted greater manipulation of the abdomen during ECV, thus improving success rates of ECV without increasing risk. ⋯ The success of external cephalic version (ECV) was compared in women who received spinal analgesia and those who did not. Successful ECV occurred more frequently in those women who received spinal analgesia. Because term singleton pregnancies associated with breech position usually require cesarean delivery, an increase in success of ECV may decrease the number of cesarean deliveries performed.
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Anesthesia and analgesia · Aug 2001
A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.
We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.