Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2000
Multicenter Study Comparative Study Clinical TrialThe effects of sevoflurane on serum creatinine and blood urea nitrogen concentrations: a retrospective, twenty-two-center, comparative evaluation of renal function in adult surgical patients.
Despite mounting clinical evidence that supports its safety, the question of the potential adverse effects of sevoflurane on renal function continues to generate some controversy. This study retrospectively evaluated pooled renal laboratory data from 22 different clinical trials that compared sevoflurane with three widely used anesthetics. The trials examined postoperative changes in serum creatinine and blood urea nitrogen levels from a total of 3, 436 ASA physical status I-IV adult surgical patients administered either sevoflurane (n = 1941) or a control drug (isoflurane, enflurane, or propofol; n = 1495) as the maintenance anesthetic. The incidences of increased serum creatinine and blood urea nitrogen concentrations were similar among patients administered sevoflurane and those administered control drugs. Additionally, no trends specific to sevoflurane were observed with respect to postoperative serum creatinine concentration and fresh gas flow rate, concurrent treatment with nephrotoxic antibiotics, or type of carbon dioxide absorbent. ⋯ Our data for changes in serum creatinine and blood urea nitrogen indicate that, for exposures of less than 4 minimum alveolar anesthetic concentration/h, sevoflurane is not associated with an increased risk of renal toxicity compared with other commonly used anesthetics. For clinical purposes, the pre- to postoperative changes in serum creatinine and blood urea nitrogen are appropriate measures of renal function in surgical patients.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialPlatelet-rich plasma sequestration, with therapeutic platelet yields, reduces allogeneic transfusion in complex cardiac surgery.
Platelet dysfunction is the most common cause of nonsurgical bleeding after cardiopulmonary bypass (CPB). We hypothesized that reinfusion of a therapeutic quantity of platelets sequestered before CPB would decrease the need for allogeneic platelet transfusion, as well as decrease bleeding and total allogeneic transfusion, in cardiac surgery patients at moderately high risk for bleeding. Fifty-five patients undergoing either reoperative coronary artery bypass (CABG) or combined CABG and valve replacement were randomized to control or platelet-rich plasma sequestration (pheresis) groups. All patients received intraoperative epsilon-aminocaproic acid infusions. There was no significant difference between groups with respect to preoperative characteristics, duration of CPB, or target postoperative hematocrit. Mean platelet yields were 6.2 +/- 2.1 units (3.1 x 10(11) platelets). Mean pheresis time was 44 min. Allogeneic platelets (range = 6-12 units) were transfused to 28% of control patients, compared with 0% of pheresis patients (P < 0.01). Allogeneic packed red blood cells were transfused to 45% of control patients (1.2 units per patient) versus 31% of pheresis patients (0. 7 unit per patient) (P = 0.35). Total allogeneic units transfused were significantly reduced in the pheresis group (P < 0.02). Mediastinal chest tube drainage was not significantly decreased in the pheresis group. In this prospective, randomized study, therapeutic platelet yields were obtained before CPB. In contrast with recent studies with low platelet yields, these data support the conclusion that platelet-rich plasma sequestration is effective in reducing allogeneic platelet transfusions and total allogeneic units transfused in cardiac surgery patients at moderately high risk for post-CPB coagulopathy and bleeding. ⋯ Transfusion of allogeneic blood products, including platelets, is common during complex cardiac surgical procedures. In the present prospective, randomized study, a significant reduction in allogeneic platelet transfusion and total allogeneic units transfused was observed after the reinfusion of a therapeutic quantity of autologous platelets sequestered before cardiopulmonary bypass.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialThe inhibition of epidural morphine-induced pruritus by epidural droperidol.
IV droperidol inhibits epidural morphine-induced pruritus, but this effect disappears when the dose is increased from 2.5 to 5.0 mg. This study was performed to determine whether epidural droperidol would have a similar effect. In this double-blinded study, we enrolled 140 patients undergoing Cesarean delivery under epidural anesthesia who were randomly allocated to four groups. Anesthesia consisted of 150 mg of 0.5% bupivacaine with 1:200,000 epinephrine, with 2 mg of morphine and 0.0, 1.25, 2.5, or 5.0 mg of droperidol (Groups 1 to 4). During the postoperative period, patients were assessed for pruritus (absent, mild, moderate, or severe) and other untoward symptoms. The chi(2) test was used to compare the incidence of the side effects. For the analysis of pruritus, we used the Mantel-Haenszel test for linear association. Droperidol induced a dose-related reduction in the incidence of pruritus (P < 0.001). This reduction was independent of the incidence of somnolence, which increased with droperidol dose (P < 0.05 when the incidence of somnolence in Groups 1 and 4 was compared). We conclude that droperidol, in doses up to 5 mg epidurally, induces a dose-related reduction in the incidence of pruritus without inducing significant side effects. ⋯ Epidural morphine is effective for pain control but yields some side effects, including pruritus, that can be severe. Studying patients undergoing Cesarean delivery, we found a dose-related reduction in the incidence of pruritus using epidural droperidol.
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Anesthesia and analgesia · Mar 2000
Spinal nerve function in five volunteers experiencing transient neurologic symptoms after lidocaine subarachnoid anesthesia.
The etiology of transient neurologic symptoms (TNS) after 5% lidocaine spinal anesthesia remains undetermined. Previous case reports have shown that patients acutely experiencing TNS have no abnormalities on neurologic examination or magnetic resonance imaging. The aim of our study was to determine whether volunteers with TNS would exhibit abnormalities in spinal nerve electrophysiology. Twelve volunteers with no history of back pain or neurologic disease underwent baseline electromyography (EMG), nerve conduction studies, and somatosensory-evoked potential (SSEP) testing. Then, the volunteers were administered 50 mg of 5% hyperbaric lidocaine spinal anesthesia and were placed in a low lithotomy position (legs on four pillows). The next day, all volunteers underwent follow-up EMG, nerve conduction, and SSEP testing and were questioned and examined for the presence of complications including TNS (defined as pain or dysthesia in one or both buttocks or legs occurring within 24 h of spinal anesthesia). Volunteers who had TNS underwent additional EMG testing 4-6 wk later. Five of the 12 volunteers reported TNS. No volunteer had an abnormal EMG, nerve conduction study, or SSEP at 24 h follow up, nor were there any changes in EMG studies at delayed testing in the five volunteers experiencing TNS. On statistical analysis, the right peroneal and the right tibial nerve differed significantly for all volunteers from pre- to postspinal testing. When comparing pre- and postspinal testing of the TNS and non-TNS volunteers, statistically significant changes occurred in the nerve conduction tests of the right peroneal and left tibial nerve. There was no difference in measurements of F response, H reflex latency, amplitude, or velocity for either leg. Multivariate analysis of variance showed no significant difference between TNS and non-TNS volunteers for the changes in the nine nerve conduction tests when considered together (P = 0.4). We conclude that acute TNS after lidocaine spinal anesthesia did not result in consistent abnormalities detectable by EMG, nerve conduction studies, or SSEP in five volunteers. ⋯ Electrophysiologic testing in volunteers experiencing transient neurologic symptoms is not abnormal.
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Anesthesia and analgesia · Mar 2000
Comparative StudyComparing methods of clinical measurement: reporting standards for bland and altman analysis.
In this era of medical technology assessment and evidence-based medicine, evaluating new methods to measure physiologic variables is facilitated by standardization of reporting results. It has been proposed that assessing repeatability be followed by assessing agreement with an established technique. If the "limits of agreement" (mean bias +/- 2SD) are not clinically important, then one could use two measurements interchangeably. Generalizability to larger populations is facilitated by reporting confidence intervals. We identified 44 studies that compared methods of clinical measurement published during 1996 to 1998 in seven anesthesia journals. Although 42 of 44 (95.4%) used the limits of agreement methodology for analysis, several inadequacies and inconsistencies in reporting the results were noted. Limits of agreement were defined a priori in 7.1%, repeatability was evaluated in 21.4%, and relationship (pattern) between difference and average was evaluated in 7.1%. Only one of the articles reported confidence intervals. A computer macro for the Minitab statistical package (State College, PA) is described to facilitate reporting of Bland and Altman analysis with confidence intervals. We propose standardization of nomenclature in clinical measurement comparison studies. ⋯ A literature review of anesthesia journals revealed several inadequacies and inconsistencies in statistical reports of results of comparison studies with regard to interchangeability of measurement methods. We encourage journal editors to evaluate submissions on this subject carefully to ensure that their readers can draw valid conclusions about the value of new technologies.