Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2002
Randomized Controlled Trial Clinical TrialContinuous psoas compartment block for postoperative analgesia after total hip arthroplasty: new landmarks, technical guidelines, and clinical evaluation.
A computed tomographic scan was obtained in 35 patients to measure the depth and the relationship of the branches of the lumbar plexus to the posterior superior iliac spine projection and the vertebral column. In addition, we prospectively studied 80 patients scheduled for total hip arthroplasty who received a continuous psoas compartment block (CPCB) in the postoperative period. CPCB was performed after surgical procedures by using modified Winnie's landmarks and nerve stimulation. From 5 to 8 cm of catheter was inserted. Radiographs were obtained after injection of 10 mL of contrast medium. An initial loading dose (0.4 mL/kg) of 0.2% ropivacaine was injected, followed by continuous infusion of 0.2% ropivacaine for 48 h. The depth of the lumbar plexus and the distance between the lumbar plexus and the L4 transverse process were measured. Visual analog scale values of pain at 1, 12, 24, and 48 h were obtained at rest and during mobilization. Amounts of rescue analgesia were also recorded. Sensory blockade of the principal branches of the lumbosacral plexus was noted at 1 and 24 h, as were adverse events related to the technique. There was a significant difference between men and women in depth of the lumbar plexus (median values, 85 vs 70 mm for men and women, respectively). There was a positive correlation between the body mass index and skin-lumbar plexus distances. In contrast, there was no difference regarding the distance between the transverse process of L4 and the lumbar plexus. The catheter tip lay within the psoas major muscle in 74% of the patients and between the psoas and quadratus lumborum muscles in 22%. In three patients, the catheter was improperly positioned. At 1 h, sensory blockade of the femoral, obturator, and lateral femoral cutaneous nerves was successful in, respectively, 95%, 90%, and 85% of patients. At 24 h, these rates were 88%, 88%, and 83%, respectively. During the 48-h study period, median visual analog scale values of pain were approximately 10 mm at rest and from 18 to 25 mm during physiotherapy. Five patients received 5 mg of morphine at 1 h. Five cases of unilateral epidural anesthesia were noted after the bolus injection. We conclude that CPCB with 0.2% ropivacaine allows optimal analgesia after hip arthroplasty, with few side effects and a small failure rate. Before lumbar plexus branch stimulation and catheter insertion, anesthesiologists should be aware of the L4 transverse process location and lumbar plexus depth. ⋯ Lumbar plexus depth is correlated with the patient's body mass index and differs between men and women, but this is not true of the lumbar plexus-transverse process distance. Considering new landmarks, a continuous psoas compartment block promotes optimal analgesia after hip arthroplasty, with few side effects.
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Anesthesia and analgesia · Jun 2002
Randomized Controlled Trial Comparative Study Clinical TrialSmall-dose propofol sedation attenuates the formation of reactive oxygen species in tourniquet-induced ischemia-reperfusion injury under spinal anesthesia.
The release of a tourniquet produces reactive oxygen species (ROS), which can cause ischemia-reperfusion injury. We investigated the effects on ROS production in 22 adult ASA physical status I-II patients sedated with small-dose propofol infusion and IV midazolam undergoing elective total knee replacement under intrathecal anesthesia, allocated randomly to one of two groups. In the Propofol group, sedation was performed with propofol 0.2 mg/kg followed by infusion at a rate of 2 mg. kg(-1). h(-1). In the Control group, IV midazolam 5 mg was given. ROS production was measured by lucigenin chemiluminescence analysis. Blood samples were obtained from the radial artery after spinal anesthesia, 1 min before release of the tourniquet and 5 and 20 min after reperfusion. The ischemic time was approximately 70 min. ROS production decreased nonsignificantly before reperfusion in both groups but increased significantly 5 and 20 min after reperfusion in the Midazolam group. In the Propofol group, no significant increase of ROS production was found. We conclude that small-dose propofol infusion attenuates ROS production in tourniquet-induced ischemia-reperfusion injury. ⋯ Small-dose propofol sedation, compared with IV midazolam, attenuates free radical production after release of the tourniquet during total knee replacement under spinal anesthesia.
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Anesthesia and analgesia · Jun 2002
Randomized Controlled Trial Clinical TrialMusic and preoperative anxiety: a randomized, controlled study.
Music may decrease the anxiety experienced by patients before surgery. Previous studies of this issue were hindered with multiple methodological problems. In this investigation, we examined this hypothesis while using a rigorous study design and objective outcome measures. Adult patients undergoing anesthesia and surgery were randomly assigned to two study groups. Subjects in Group 1 (n = 48) listened to a 30-min patient-selected music session, and subjects in Group 2 (n = 45) received no intervention. By using self-report validated behavioral (State-Trait Anxiety Inventory) and physiological measures of anxiety (heart rate, blood pressure, and electrodermal activity and serum cortisol, epinephrine, and norepinephrine), patients were evaluated before, during, and after administration of the intervention. We found that after intervention, subjects in the Music group reported significantly lower anxiety levels as compared with the Control group (F(1,91) = 15.4, P = 0.001). That is, the postintervention anxiety level of subjects in the Music group decreased by 16% as compared with the preintervention level, whereas the anxiety level of the Control group did not change significantly. Two-way repeated-measures analysis of variance performed for the electrodermal activity, blood pressure, heart rate, cortisol, and catecholamine data demonstrated no group difference and no time x group interaction (P = not significant). In conclusion, under the conditions of this study, patients who listened to music before surgery reported lower levels of state anxiety. Physiological outcomes did not differ, however, between the two study groups. ⋯ Patients who listen to music of their choice during the preoperative period report less anxiety.
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Anesthesia and analgesia · Jun 2002
Randomized Controlled Trial Clinical TrialThe minimum local anesthetic concentration of ropivacaine for caudal analgesia in children.
Ropivacaine is a new long-acting amino-amide local anesthetic. The concentrations of ropivacaine used in caudal analgesia range from 0.1% to 0.5%. The purpose of this study was to determine the minimum local analgesic concentration of ropivacaine to provide caudal analgesia in children. In a prospective, randomized, double-blinded clinical study, we studied 26 ASA grade I patients aged 1 to 5 yr who were scheduled for hypospadias operation under general anesthesia with caudal ropivacaine analgesia. General anesthesia was maintained with an end-tidal enflurane concentration of 0.8% in 100% oxygen (0.5 minimum alveolar anesthetic concentration [MAC]). Each child received 1 mL/kg of ropivacaine solution through a caudal catheter. The first child received ropivacaine 0.2%, and subsequent concentrations were determined by the analgesic response of the previous patient to the initial skin incision by use of Dixon's up-and-down sequential allocation. The testing interval was set at 0.025%. The minimum local analgesic concentration of ropivacaine for caudal analgesia under general anesthesia with 0.5 MAC enflurane was 0.11% (95% confidence interval [CI], 0.09%-0.12%), and the 95% effective concentration was 0.13% (95% CI, 0.12%-0.21%). In conclusion, the minimum local analgesic concentration of ropivacaine to provide effective caudal analgesia in children under general anesthesia with 0.5 MAC enflurane was found to be 0.11% (95% CI, 0.09%-0.12%). ⋯ Ropivacaine is a new long-acting amino-amide local anesthetic. The concentrations of ropivacaine used in caudal analgesia ranged from 0.1% to 0.5%. This study determined the minimum local analgesic concentration of ropivacaine to establish effective caudal analgesia under general anesthesia with 0.5 minimum alveolar anesthetic concentration enflurane in children.
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Anesthesia and analgesia · Jun 2002
Randomized Controlled Trial Clinical TrialSlow rewarming has no effects on the decrease in jugular venous oxygen hemoglobin saturation and long-term cognitive outcome in diabetic patients.
The purpose of this study was to examine the effects of rewarming rate on internal jugular venous oxygen hemoglobin saturation (SjvO(2)) during the rewarming period, and long-term cognitive outcome in diabetic patients. We studied 30 diabetic patients scheduled for elective coronary artery bypass graft surgery. As a control, 30 age-matched nondiabetic patients were identified. The diabetic patients were randomly divided into two groups: the Slow Rewarming group (n = 15) (mean rewarming speed: 0.22 degrees +/- 0.07 degrees C/min, mean +/- SD) or the Standard Rewarming group (Standard group) (n = 15) (mean rewarming speed: 0.46 degrees +/- 0.09 degrees C/min, mean +/- SD). After the induction of anesthesia, a fiberoptic oximetry catheter was inserted into the right jugular bulb to monitor SjvO(2) continuously. Hemodynamic variables and arterial and jugular venous blood gases were measured at nine time points. All patients underwent a battery of neurologic and neuropsychologic tests on the day before the operation and at 4 mo after surgery. The SjvO(2) values in the Standard group were decreased during the rewarming period compared with at the induction of anesthesia (P < 0.05). There was a significant difference in the SjvO(2) value in the Control group between standard rewarming and slow rewarming during rewarming periods (Standard Control group: 51% +/- 8%, Slow Control groups: 58% +/- 5%) (P < 0.05). However, there was no difference in the SjvO(2) value in diabetic patients between standard rewarming and slow rewarming during the rewarming period. The rewarming rates (odds ratio: 0.8; 95% confidence interval: 0.5-1.3; P = 0.6) had no correlation with cognitive impairment at 4 mo after the surgery. Diabetes (odds ratio: 1.6; 95% confidence interval: 0.9-2.6; P = 0.04) was a factor in relation to cognitive impairment at 4 mo after the surgery. We concluded that a slow rewarming rate had no effects on the reduction in SjvO(2) value and long-term cognitive outcome in diabetic patients. ⋯ We examined the effects of rewarming rate on internal jugular venous oxygen hemoglobin saturation in diabetic and nondiabetic patients during the rewarming period and long-term cognitive outcome. Slow rewarming could not prevent the frequency of the reduction in internal jugular venous oxygen hemoglobin saturation and adverse cognitive outcome in diabetic patients.