Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Clinical TrialRapid deflation of the bronchial cuff of the double-lumen tube after decreasing the concentration of inspired nitrous oxide.
Deflationary phenomena of the endotracheal tube cuff may occur after inspired nitrous oxide (N(2)O) concentrations are reduced, but deflationary phenomena of the double-lumen tube (DLT) cuff have not been investigated. In this study, tracheal and bronchial cuffs of left-sided Mallinckrodt (Athlone, Ireland) DLTs were inflated with air, 40% N(2)O, or 67% N(2)O (Air, N40, or N67 groups, respectively) in 24 patients undergoing thoracic surgery; 40 min later, O(2) was substituted for N(2)O in some of the patients in the N40 group (N40-c group). Intracuff gas volumes, N(2)O concentrations, and cuff compliance were also measured. Both tracheal and bronchial cuff pressures significantly increased in the Air group but decreased in the N67 group. Neither pressure significantly changed in the N40 group, but both decreased in the N40-c group after terminating N(2)O anesthesia; the time required for bronchial cuff pressures to decrease by half (12.0 +/- 5.5 min) was less than that for tracheal cuff pressures (31.2 +/- 11.0 min, P < 0.01). The volume change in the N40-c group was not significantly different between the tracheal and bronchial cuffs, but tracheal cuff compliance was significantly higher than bronchial compliance. Therefore, filling DLT cuffs with 40% N(2)O stabilizes cuff pressure during anesthesia with 67% N(2)O, but bronchial cuffs deflate more quickly than tracheal cuffs after cessation of N(2)O administration through smaller compliance. ⋯ We demonstrated that after cessation of nitrous oxide (N(2)O) administration, bronchial N(2)O-filled cuffs of the double-lumen tube deflate more rapidly than tracheal cuffs. To avoid insufficient separation of the lungs by the bronchial cuff, a frequent check of the cuff pressure is recommended after the inspired N(2)O concentration is decreased.
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Anesthesia and analgesia · Jul 2002
Comparative Study Clinical TrialLevobupivacaine for axillary brachial plexus block: a pharmacokinetic and clinical comparison in patients with normal renal function or renal disease.
We compared the pharmacokinetics and clinical characteristics of 0.5% levobupivacaine for axillary block in patients with normal renal function versus patients with end-stage renal disease (ESRD). Twenty patients with normal renal function and eight patients with ESRD received an axillary block with 50-60 mL of 0.5% levobupivacaine. Patients were evaluated for onset and duration of sensory/motor block. Eleven patients with normal renal function and eight patients with ESRD underwent pharmacokinetic analysis. No differences between groups were found in the onset, duration, or quality of block. The median time to sensory block was 12.5 min and 12.9 min, and mean duration of the block was 19 h and 22 h in normal versus ESRD patients, respectively. No significant differences in noncompartmental pharmacokinetic variables (median) were found between normal and ESRD patients with an AUC(0-t) (microg. h(-1). mL(-1)) of 11 and 13, peak concentration (C(max)) (microg/mL) of 1.2 and 1.6, and a time to peak concentration (T(max)) (min) of 55 and 48, respectively. This study demonstrates the clinical efficacy and equivalence of the pharmacokinetic characteristics of 0.5% levobupivacaine for axillary brachial plexus block in patients with ESRD and normal renal function. ⋯ This study demonstrates the clinical efficacy and equivalence of the pharmacokinetic characteristics of 0.5% levobupivacaine for axillary brachial plexus block in patients with renal disease and normal renal function.
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Anesthesia and analgesia · Jul 2002
Clinical TrialInsufficiency in a new temporal-artery thermometer for adult and pediatric patients.
SensorTouch is a new noninvasive temperature monitor and consists of an infrared scanner that detects the highest temperature on the skin of the forehead, presumably over the temporal artery. The device estimates core temperature (T(core)). We tested the hypothesis that the SensorTouch is sufficiently precise and accurate for routine clinical use. We studied adults (n = 15) and children (n = 16) who developed mild fever, a core temperature of at least 37.8 degrees C, after cardiopulmonary bypass. Temperature was recorded at 15-min intervals throughout recovery with the SensorTouch thermometer and from the pulmonary artery (adults) or bladder (children). Pulmonary artery (T(core)) and SensorTouch (T(st)) temperatures correlated poorly in adults: T(core) = 0.7. T(st) + 13, r(2) = 0.3. Infrared and pulmonary artery temperatures differed by 1.3 +/- 0.6 degrees C; 89% of the adult temperatures thus differed by more than 0.5 degrees C. Bladder and infrared temperatures correlated somewhat better in pediatric patients: T(core) = 0.9. T(st) + 12, r(2) = 0.6. Infrared and bladder temperatures in children differed by only 0.3 degrees C, but the SD of the difference was 0.5 degrees C. Thus, 31% of the values in the infants and children differed by more than 0.5 degrees C. ⋯ We evaluated a noninvasive infrared forehead thermometer (SensorTouch) in adult and pediatric cardiac patients. Accuracy was poor in the adults and suboptimal in infants and children.
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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
Case ReportsThe use of the intubating laryngeal mask endotracheal tube with intubating devices.
Despite adequate visualization of the vocal cords using specialized airway devices, anatomical factors and the physical characteristics of the tube may cause difficulty when performing endotracheal intubation. The endotracheal tube designed for use with the intubating laryngeal mask airway may facilitate intubation in these circumstances.