Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2003
Randomized Controlled Trial Clinical TrialA single small dose of postoperative ketamine provides rapid and sustained improvement in morphine analgesia in the presence of morphine-resistant pain.
It is a common clinical observation that postoperative pain may be resistant to morphine. The analgesic potentials of ketamine have also been well documented. In this study, we evaluated the effects of postoperative coadministration of small doses of ketamine and morphine on pain intensity, SpO(2), and subjectively rated variables in surgical patients who underwent standardized general anesthesia and complained of pain (> or =6 of 10 on a visual analog scale [VAS]) despite >0.1 mg/kg of i.v. morphine administration within 30 min. Patients randomly received up to three boluses of 30 microg/kg of morphine plus saline (MS; n = 114) or 15 microg/kg of morphine plus 250 microg/kg of ketamine (MK; n = 131) within 10 min in a double-blinded manner. The MS group's pain VAS scores were 5.5 +/- 1.18 and 3.8 +/- 0.9 after 10 and 120 min, respectively, after 2.52 +/- 0.56 injections, versus the MK group's VAS scores of 2.94 +/- 1.28 and 1.47 +/- 0.65, respectively (P < 0.001), after 1.35 +/- 0.56 injections (P < 0.001). The 10-min level of wakefulness (1-10 VAS) in the MS group was significantly (P < 0.001) less (6.1 +/- 1.5) than the MK group's (8.37 +/- 1.19). SpO(2) decreased by 0.26% in the MS group but increased by 1.71% in the MK patients at the 10-min time point (P < 0.001). Thirty MS versus nine MK patients (P < 0.001) experienced nausea/vomiting; nine MK patients sustained a 2-min light-headed sensation, and one patient had a weird dream after the second drug injection. ⋯ A small-dose ketamine and morphine regimen interrupted severe postoperative pain that was not relieved previously by morphine. Ketamine reduced morphine consumption and provided rapid and sustained improvement in morphine analgesia and in subjective feelings of well-being, without unacceptable side effects.
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Anesthesia and analgesia · Mar 2003
Clinical TrialPatient-controlled epidural analgesia in children: can they do it?
Extensive clinical experience and many studies support the use of i.v. patient-controlled analgesia (i.v. PCA) and regional anesthesia techniques for the treatment of postoperative pain in children. In contrast, little has been reported about the ability of children to use patient-controlled epidural analgesia (PCEA) or about the efficacy of this technique. We report a descriptive analysis of prospectively recorded data in 128 children (132 procedures) in whom PCEA was used for acute postoperative pain control. Satisfactory analgesia was obtained in 119 patients (90.1%) for up to 103 h with no episodes of desaturation and without clinical evidence of toxicity or serious adverse effects. Analgesia was satisfactory with the initial settings in 89 patients; in 38 others, this was achieved with changes in PCEA settings or solution. Five patients were switched to i.v. PCA because of inadequate analgesia. Eight patients with satisfactory analgesia were converted to i.v. PCA because of adverse effects. Children as young as 5 yr had the cognitive ability to understand and the willingness to use PCEA, consistent with reported use of i.v. PCA. Careful attention should be paid to the total hourly local anesthetic dose to avoid exceeding the recommended limits. Our prospectively collected data demonstrate that PCEA provides satisfactory analgesia with a small incidence of adverse side effects in children and should be considered along with other strategies in pediatric postoperative pain management. ⋯ A descriptive analysis of prospectively recorded data in 132 children receiving patient-controlled epidural analgesia for postoperative pain relief demonstrates satisfactory analgesia without serious toxicity or side effects in children as young as 5 yr. This modality should be considered as another strategy in pediatric postoperative pain management.
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Anesthesia and analgesia · Mar 2003
Clinical TrialPredictor of core hypothermia and the surgical intensive care unit.
Inadvertent postoperative core hypothermia is associated with multiple physiological effects, especially in patients admitted to the intensive care unit (ICU). Despite previous reports of the relationship between patient, surgical, and anesthetic factors and immediate postoperative core hypothermia, this information might need to be reconsidered in the light of progress in surgery, anesthetic, and warming techniques. We designed this prospective study of 194 postgeneral surgical patients to assess the incidence, predictive factors, and outcome of core hypothermia (tympanic membrane core temperature [Tc] <36.0 degrees C) at the time of admission to the general ICU in a large tertiary university medical center from December 2000 to March 2001. The following variables were studied: age, sex, body weight, body surface area, preoperative body temperature, ASA physical status, history of diabetic neuropathy, emergency surgery, surgical subspecialty performing surgery, type of surgery, type of anesthesia (general, regional, or combined epidural and general), temperature monitoring, use of a forced air warming technique, amount of fluid and blood replacement, duration of anesthesia, duration of surgery, and the ambient operating room temperature. Other outcomes, i.e., length of ICU stay and mortality, were also assessed. The incidence of core hypothermia was 57.1%, 41.3%, and 28.3% according to the definition of Tc <36.0 degrees C, <35.5 degrees C, and <35.0 degrees C, respectively. Multiple logistic regression showed the following risk factors for core hypothermia: high ASA physical status (odds ratio, 2.87; 95% confidence interval [CI], 0.82-10.03 for ASA II; odds ratio, 8.35; 95% CI, 1.67-41.88 for ASA >II), magnitude of surgical procedure (odds ratio, 6.60; 95% CI, 1.66-26.19 for medium surgery; odds ratio, 22.23; 95% CI, 5.41-91.36 for major surgery), use of combined epidural and general anesthesia (odds ratio, 3.39; 95% CI, 1.05-10.88), and duration of surgery >2 h (odds ratio, 4.50; 95% CI, 1.48-13.68). Not using temperature monitoring seems to be a risk factor as well (odds ratio, 3.00; 95% CI, 0.87-10.12). Significant protective factors against core hypothermia were heavier body weight (odds ratio, 0.94; 95% CI, 0.89-0.98), higher preoperative body temperature (odds ratio, 0.31; 95% CI, 0.15-0.65), and warmer ambient operating room temperature (odds ratio, 0.67; 95% CI, 0.51-0.88). In conclusion, the incidence of core hypothermia (Tc <36.0 degrees C) at the time of admission to the general ICU is still frequent. To reduce the incidence, more efforts and concern should be taken to prevent core hypothermia, especially in the patient with high ASA physical status, undergoing more intensive and lengthy surgery, and using combined epidural and general anesthesia. ⋯ In an effort to decrease the frequent incidence of core hypothermia at the time of admission to the general surgical intensive care unit, this prospective study showed that high ASA physical status, the use of a combined epidural and general anesthesia, surgery lasting longer than 2 h, and extensive surgery were the important risk factors, whereas heavier body weight, higher preoperative body temperature, and warmer ambient operating room temperature were important protective factors.
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Anesthesia and analgesia · Mar 2003
Comparative StudyOrganizational factors affect comparisons of the clinical productivity of academic anesthesiology departments.
Productivity measurements based on "per operating room (OR) site" and "per case" are not influenced by staffing ratios and have permitted meaningful comparisons among small samples of both academic and private-practice anesthesiology groups. These comparisons have suggested that a larger sample would allow for clinical groups to be compared using a number of different variables (including type of hospital, number of OR sites, type of surgical staff, or other organizational characteristics), which may permit more focused benchmarking. In this study, we used such grouping variables to compare clinical productivity in a broad survey of academic anesthesiology programs. Descriptive, billing, and staffing data were collected for 1 fiscal or calendar year from 37 academic anesthesiology departments representing 58 hospitals. Descriptive data included types of surgical staff (e.g., academic versus private practice) and hospital centers (e.g., academic medical centers and ambulatory surgical centers [ASCs]). Billing and staffing data included total number of cases performed, total American Society of Anesthesiologists units (tASA) billed, total time units billed (15-min units), and daily number of anesthetizing sites staffed (OR sites). Measurements of total productivity (tASA/OR site), billed hours per OR site per day (h/OR/d), surgical duration (h/case), hourly billing productivity (tASA/h), and base units/case were compared. These comparisons were made according to type of hospital, number of OR sites, and type of surgical staff. The ASCs had significantly less tASA/OR site, fewer h/OR/d, and less h/case than non-ASC hospitals. Community hospitals had significantly less h/OR/d and h/case than academic medical centers and indigent hospitals and a larger percentage of private-practice or mixed surgical staff. Academic staffs had significantly less tASA/h and significantly more h/case. tASA/h correlated highly with h/case (r = -0.68). This study showed that the hospitals at which academic anesthesiology groups provide care are not all the same from a clinical productivity perspective. By grouping based on type of hospital, number of OR sites, and type of surgical staff, academic anesthesiology departments (and hospitals) can be better compared by using clinical productivity measurements based on "per OR site" and "per case" measurements (tASA/OR, billed h/OR/d, h/case, tASA/h, and base/case). ⋯ Organizational factors, including type of hospital, number of operating rooms, and type of surgical staff, influence the clinical productivity of academic anesthesiology departments. Reporting quartile data by focused grouping variables allows anesthesiology groups to compare their clinical productivity with groups practicing in similar clinical settings.
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Anesthesia and analgesia · Mar 2003
Clinical TrialChanges in consciousness, conceptual memory, and quantitative electroencephalographical measures during recovery from sevoflurane- and remifentanil-based anesthesia.
It is unclear whether opioid-induced changes in electroencephalogram (EEG) or auditory evoked potentials (AEPs) reliably correspond with consciousness. We examined the correlation between 1) the clinically assessed state of consciousness, 2) implicit and explicit memory (by use of word pairs), and 3) various measures of EEG and AEP-bispectral index (BIS), A-Line ARX AEP index, spectral entropy, and entropy of the singular value decomposition (SVDEN; a measure of the complexity of the EEG). We studied 21 women during a two-stage awakening (sevoflurane washout followed by remifentanil washout) after anesthesia for gynecological surgery. All were amnesic, and 19 were unresponsive to verbal command with remifentanil alone. In six patients, BIS decreased paradoxically as the remifentanil concentration decreased; this was caused by a low-amplitude EEG, which was misinterpreted by the Aspect algorithm as burst suppression. Most of the EEG/AEP variables were sensitive to the decrease in sevoflurane and the recovery of consciousness, but not to the effects of decreasing remifentanil concentrations. SVDEN was the only variable that demonstrated significant increases for both the sevoflurane and remifentanil washout phases. With the prediction probability statistic during remifentanil washout, SVDEN = 0.79, spectral entropy = 0.81, A-Line ARX AEP index = 0.63, and BIS = 0.58. Entropy measures appear to be worthy of further clinical evaluation in a larger series of patients. SVDEN may be a useful variable for assessing anesthetic and analgesic effects on the central nervous system. ⋯ During the recovery phase from a remifentanil-based anesthetic, the bispectral index is not reliably predictive of the depth of consciousness, because of suppression ratio artifacts. Entropy measures of the electroencephalogram show promise, but there is still no gold standard to estimate anesthetic depth.