Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2002
Sampling error can significantly affect measured hospital financial performance of surgeons and resulting operating room time allocations.
Hospitals with limited operating room (OR) hours, those with intensive care unit or ward beds that are always full, or those that have no incremental revenue for many patients need to choose which surgeons get the resources. Although such decisions are based on internal financial reports, whether the reports are statistically valid is not known. Random error may affect surgeons' measured financial performance and, thus, what cases the anesthesiologists get to do and which patients get to receive care. We tested whether one fiscal year of surgeon-specific financial data is sufficient for accurate financial accounting. We obtained accounting data for all outpatient or same-day-admit surgery cases during one fiscal year at an academic medical center. Linear programming was used to find the mix of surgeons' OR time allocations that would maximize the contribution margin or minimize variable costs. Confidence intervals were calculated on these end points by using Fieller's theorem and Monte-Carlo simulation. The 95% confidence intervals for increases in contribution margins or reductions in variable costs were 4.3% to 10.8% and 6.0% to 8.9%, respectively. As many as 22% of surgeons would have had OR time reduced because of sampling error. We recommend that physicians ask for and OR managers get confidence intervals of end points of financial analyses when making decisions based on them. ⋯ The common approach of using one fiscal year of perioperative accounting data can be insufficient to prevent random error from influencing important management decisions. When accounting data are used for hospital and operating room management decision making, confidence intervals should be calculated for the key financial variables (e.g., variable cost per hour of operating room time).
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Anesthesia and analgesia · Jul 2002
Clinical TrialMyocardial ischemia and cytokine response are associated with subsequent onset of infections after noncardiac surgery.
Postoperative myocardial ischemia (POMI) is prevalent among patients after major noncardiac surgery. Surgery, as well as POMI, may modulate the immune system, potentially worsening patient outcome. We sought to investigate the modulation of soluble interleukin (IL)-6 and IL-10 by POMI and its association with increased postoperative infection rates. Two-hundred-three patients undergoing elective major abdominal, vascular, and orthopedic surgery participated in this prospective observational study. Perioperative management was standardized. Hemodynamic variables were kept within 20% of baseline. POMI was assessed by Holter electrocardiography starting at least 8 h before the induction of anesthesia and continued until 96 h after surgery. Twelve-lead electrocardiograms, cardiac enzymes, and immune variables were obtained at the time of admission to the hospital, before surgery, before the induction of anesthesia, after surgery, at the time of admission to the intensive care unit, and 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, and 168 h after surgery. Infections were diagnosed according to the Centers for Disease Control criteria. The incidence of POMI was 27%, and the majority of cases (76%) occurred within the first 24 h after surgery. IL-6 and IL-10 levels significantly increased during surgery but did not differ between the POMI and Non-POMI groups. However, in the subset of patients who developed severe infections or sepsis (n = 47) a median of 3 days (range, 1-8 days) after surgery, the intraoperative increases of IL-6 and IL-10 in the POMI group were, respectively, 3 and 10 times higher compared with the increase in the Non-POMI group. By using a multifactorial analysis in these patients with severe infections, the type of surgical trauma was associated with an increased IL-6 response, whereas the increase in IL-10 was attributed to POMI. These findings suggest that immediate cytokine responses due to POMI and type of surgery might be relevant for the later onset of severe infections and sepsis. ⋯ Postoperative myocardial ischemia (POMI) occurred in 27% of patients after major noncardiac surgery. This was associated with an immediate augmented cytokine response in the first 12 h after surgery in patients who developed severe infections or sepsis 3 days later. POMI was associated with an increased interleukin (IL)-10 response, whereas IL-6 was associated with the type of surgery.
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We studied the incidence of awareness and explicit recall during general anesthesia in outpatients versus inpatients undergoing surgery. During a 14.5-mo period, we structurally interviewed 1500 outpatients and 2343 inpatients. Among outpatients, there were five cases of awareness and recall (one with clear intraoperative recollections and four with doubtful intraoperative recollections). Of the inpatients, six reported awareness and recall (three with clear and three with doubtful intraoperative recollections). The incidence of clear intraoperative recollections was 0.07% in outpatients and 0.13% in inpatients. The difference in the incidence was not significant. Among outpatients, those with awareness and recall were given smaller doses of sevoflurane than those without awareness and recall (P < 0.05). In conclusion, awareness and recall are rare complications of general anesthesia, and outpatients are not at increased risk for this event compared with inpatients undergoing general anesthesia. ⋯ Rapid recovery from general anesthesia is a crucial element of outpatient surgery. However, this practice may predispose a patient to receive less anesthetic, with increased risk for awareness and recall. We have shown that outpatients undergoing an operation using general anesthesia are not at increased risk for awareness compared with inpatients.
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Anesthesia and analgesia · Jul 2002
Modeling the effect of progressive endotracheal tube occlusion on tidal volume in pressure-control mode.
A recognized hazard of prolonged endotracheal intubation is progressive airway occlusion resulting from deposition of secretions on the inner surface of the endotracheal tube (ETT). When volume-controlled ventilation is used, progressive ETT occlusion may be detected by monitoring the difference between peak and plateau airway pressures. In pressure-controlled modes, however, inspiratory airway pressures are preset and thus cannot act as a warning indicator. Instead, changes in delivered tidal volumes may aid the diagnosis of ETT occlusion. To determine whether tidal volume monitoring effectively detects progressive ETT occlusion, we mathematically modeled the response of a ventilator operating in pressure-controlled mode to increasing airway resistance. To corroborate our model, we then bench-tested the Siemens 300 and Puritan-Bennett 7200 ventilators by using a test lung and a series of ETTs ranging in size from 9.0 to 3.5 mm inner diameter to simulate progressive occlusion. We found that when pressure-controlled mode was used, progressive ETT occlusion did not reduce delivered tidal volumes until occlusion was nearly complete. We conclude that prolonged use of pressure-controlled mode may allow significant ETT obstruction to build up undetected, risking complete ETT occlusion and complicating the perioperative care of patients ventilated with this mode. ⋯ Although increasing airway pressures during volume-controlled ventilation allow early recognition of endotracheal tube (ETT) obstruction, airway pressures with pressure-controlled ventilation are fixed. We found during tests of two intensive care unit ventilators that although ETT obstruction reduces delivered tidal volumes during pressure-controlled ventilation, reductions do not occur until occlusion is advanced.
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Anesthesia and analgesia · Jul 2002
Case ReportsThe resolution of ST segment depressions after high right thoracic paravertebral block during general anesthesia.
Thoracic epidural, stellate ganglion, and thoracic paravertebral blocks all relieve angina. We report a case of intraoperative resolution of ST segment depression after a right thoracic paravertebral block.