Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2001
Comparative Study Clinical TrialStroke volume variation as a predictor of fluid responsiveness in patients undergoing brain surgery.
Changes in arterial blood pressure induced by mechanical ventilation allow assessment of cardiac preload. In this study, stroke volume variation (SVV), which is the percentage change between the maximal and minimal stroke volumes (SV) divided by the average of the minimum and maximum over a floating period of 30 s, continuously displayed by the PiCCO continuous cardiac output monitor, was evaluated as a predictor of fluid responsiveness. Fifteen patients undergoing brain surgery were included. During surgery, graded volume loading was performed with each volume loading step (VLS) consisting of 100 mL of 6% hydroxyethylstarch given for 2 min. Successive responsive VLSs were performed (increase in SV > 5% after a VLS) until a change in SV of < 5 % was reached (nonresponsive). A total of 140 VLSs were performed. Responsive and nonresponsive VLSs differed in their pre-VLS values of systolic blood pressure, SV, and SVV, but not in the values of heart rate and central venous pressure. By using receiver operating characteristic analysis, the area under the curve for SVV (0.870, 95% confidence interval [CI]: 0.809 to 0.903) was statistically more than those for central venous pressure (0.493, 95% CI: 0.397 to 0.590, P = 7 x 10(-10)), heart rate (0.593, 95% CI: 0.443 to 0.635, P = 5.7 x 10(-10)), and systolic blood pressure (0.729, 95% CI: 0.645 to 0.813, P: = 4.3 x 10(-3)). An SVV value of 9.5% or more, will predict an increase in the SV of at least 5% in response to a 100-mL volume load, with a sensitivity of 79% and a specificity of 93%. ⋯ Stroke volume variation may be used as a continuous preload variable and in combination with the continuously measured cardiac output, defining on-line the most important characteristics of cardiac function, allowing for optimal fluid management.
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Anesthesia and analgesia · Apr 2001
Randomized Controlled Trial Clinical TrialVoluven, a lower substituted novel hydroxyethyl starch (HES 130/0.4), causes fewer effects on coagulation in major orthopedic surgery than HES 200/0.5.
Hydroxyethyl starch (HES) solutions are effective plasma volume expanders. Impairment of coagulation occurs with large HES volumes infused perioperatively. Therefore, a lower substituted novel HES (Voluven; Fresenius Kabi, Bad Homburg, Germany) was developed to minimize hemostatic interactions, and was compared with HAES-steril (Fresenius Kabi) (pentastarch) regarding safety and efficacy. We performed a prospective, randomized, double-blinded study in 100 major orthopedic surgery patients. Because the 95% confidence interval (-330 mL; +284 mL) for the treatment contrast Voluven-HAES-steril was entirely included in the predefined equivalence range (+/- 500 mL), comparable efficacy was established. Voluven interfered significantly less than HAES-steril with coagulation factor VIII levels and partial thromboplastin time postoperatively. Total amounts of red blood cells transfused were comparable between the Voluven and HAES-steril groups, but a significantly reduced need for homologous red blood cells was observed in the Voluven group. We conclude that in large-blood-loss surgery, Voluven has a comparable efficacy with HAES-steril and may reduce coagulation impairment, possibly leading to a smaller number of allogeneic blood transfusions. ⋯ Hydroxyethyl starches are common plasma volume expanders, but may interfere with coagulation at large doses. We tested a novel hydroxyethyl starch specification (Voluven; Fresenius Kabi, Bad Homburg, Germany) which was developed to reduce hemostatic interactions while preserving its efficacy in restoring plasma volume in comparison to HAES-steril (pentastarch; Fresenius Kabi) in major orthopedic surgery.
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Anesthesia and analgesia · Apr 2001
Meta Analysis Comparative StudyA lack of evidence of superiority of propofol versus midazolam for sedation in mechanically ventilated critically ill patients: a qualitative and quantitative systematic review.
Propofol and midazolam are often used for sedation in the intensive care unit. The aim of this systematic review was to estimate the efficacy and harm of propofol versus midazolam in mechanically ventilated patients. A systematic search (Medline, Cochrane Library, Embase, bibliographies), any language, up to June 1999 was performed for reports of randomized comparisons of propofol with midazolam. Data from 27 trials (1624 adults) were analyzed. The average duration of sedation varied between 4 and 339 h. In 10 trials, the duration of adequate sedation was longer with propofol (weighted mean difference 2.9 h; 95% confidence interval [CI], 0.2-5.6 h). In 13 trials (mostly postoperative), sedation lasted 4 to 35 h; in 9 of those, average weaning time from mechanical ventilation with propofol was 0.8-4.3 h; with midazolam it was 1.5-7.2 h (weighted mean difference 2.2 h [95% CI, 0.8 to 3.7 h]). In 8 trials, sedation lasted 54 to 339 h; there was a lack of evidence for difference in weaning times. Arterial hypotension (relative risk 2.5 [95% CI, 1.3 to 4.5]; number-needed-to-treat, 12), and hypertriglyceridemia (relative risk 12.1 [95%CI, 2.9 to 49.7]; number-needed-to-treat, 6) occurred more often with propofol. The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation <36 h, weaning is faster with propofol. ⋯ The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation < 36 h, weaning is faster with propofol.
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Anesthesia and analgesia · Apr 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of ropivacaine with fentanyl to bupivacaine with fentanyl for postoperative patient-controlled epidural analgesia.
Ropivacaine for patient-controlled epidural analgesia (PCEA) may facilitate postoperative patient mobilization because it causes less motor block than bupivacaine. Forty patients undergoing abdominal surgery were randomized in a double-blinded manner to the following: 0.05% bupivacaine/4 microg fentanyl, 0.1% bupivacaine/fentanyl, 0.05% ropivacaine/fentanyl, or 0.1% ropivacaine/fentanyl for standardized PCEA. We measured pain scores, side effects, and PCEA consumption for 42 h. Lower-extremity motor function was assessed with electromyography and isometric force dynamometry. Analgesia was equivalent among groups. Local anesthetic use was more in the 0.1% Ropivacaine and 0.1% Bupivacaine groups (77% increase, P = 0.001). Motor function decreased during PCEA (10%-35% decrease from preoperative, P < 0.001) and was equivalent among groups. Eight patients were transiently unable to ambulate. These patients used more local anesthetic (45 vs 33 mg mean, P < 0.05) with additional decrease in motor function (32%, P < 0.004) compared with ambulating patients. Other side effects were mild and equivalent among solutions. PCEA with bupivacaine/fentanyl and ropivacaine/fentanyl as 0.05% or 0.1% solutions appears clinically equipotent. Lower-extremity motor function decreases, but is unlikely to result in prolonged inability to ambulate. Use of a 0.05% solution may be advantageous to decrease local anesthetic use and prevent transient motor block. ⋯ Patient-controlled epidural analgesia with bupivacaine/fentanyl and ropivacaine/fentanyl as either 0.05% or 0.1% solutions are clinically similar. Lower-extremity motor function will decrease with the use of any of these combinations, but is unlikely to result in the inability to walk.