Epidural clonidine or bupivacaine as the sole analgesic agent during and after abdominal surgery: a comparative study.
(17/1144)
BACKGROUND: The rationale of this study was to compare high-dose epidural clonidine with a more commonly used agent, such as bupivacaine. This was performed to give a more objective idea of the relative analgesic potency of epidural clonidine. METHODS: Sixty patients undergoing intestinal surgery during propofol anesthesia were studied. At induction, the patients received epidurally a dose of 10 micrograms/kg [corrected] clonidine in 7 ml saline followed by an infusion of 6 micrograms [corrected] x kg(-1) x h(-1) (7 ml/h) (group 1, n = 20), a dose of 7 ml bupivacaine, 0.5%, followed by 7 ml/h bupivacaine, 0.25% (group 2, n = 20), or a dose of 7 ml bupivacaine, 0.25%, followed by 7 ml/h bupivacaine, 0.125% (group 3, n = 20). Intraoperatively, increases in arterial blood pressure or heart rate not responding to propofol (0.5 mg/kg) were treated with intravenous alfentanil (0.05 mg/kg). Additional doses of propofol were given to maintain an adequate bispectral index. The epidural infusions were maintained for 12 h. In cases of subjective visual analogue pain scores up to 5 cm at rest or up to 8 cm during coughing, the patients were given access to a patient-controlled analgesia device. RESULTS: During anesthesia, patients in group 1 required less propofol than those in groups 2 and 3 (78 [36-142] mg vs. 229 [184-252] mg and 362 [295-458] mg; P < 0.05) and less alfentanil than patients in group 3 (0 [0-0] mg vs. 11 [6-20] mg; P < 0.05). Analgesia lasted 380 min (range, 180-645 min) in group 1 versus 30 min (range, 25-40 min) in group 2 and 22 min (range, 12.5-42 min) in group 3 (P < 0.05). There was no suggestion of a hemodynamic difference among the three groups except for heart rates that were significantly reduced in patients in group 1. Sedation scores were significantly higher in this group during the first 2 h postoperatively. CONCLUSION: Our results show that high doses of epidural clonidine potentiate general anesthetics and provide more efficient postoperative analgesia than the two bupivacaine dosage regimens investigated. (+info)
Functional expression of an inactivating potassium channel (Kv4.3) in a mammalian cell line.
(18/1144)
OBJECTIVE: The goal of this study was to characterize the electrophysiological properties of the Kv4.3 channels expressed in a mammalian cell line. METHODS: Currents were recorded using the whole-cell voltage clamp technique. RESULTS: The threshold for activation of the expressed Kv4.3 current was approximately -30 mV. The dominant time constant for activation was 1.71 +/- 0.16 ms (n = 10) at +60 mV. The current inactivated, this process being incomplete, resulting in a sustained level which contributed 15 +/- 2% (n = 25) of the total current. The time course of inactivation was fit by a biexponential function, the fast component contributing 74 +/- 5% (n = 9) to the overall inactivation. The fast time constant was voltage-dependent [27.6 +/- 2.0 ms at +60 mV (n = 10) versus 64.0 +/- 3.6 ms at 0 mV (n = 10); P < 0.01], whereas the slow was voltage-independent [142 +/- 15 ms at +60 mV (n = 10) versus 129 +/- 33 ms at 0 mV (n = 6) P > 0.05]. The voltage-dependence of inactivation exhibited midpoint and slope values of -26.9 +/- 1.5 mV and 5.9 +/- 0.3 mV (n = 21). Recovery from inactivation was faster at more negative membrane potentials [203 +/- 17 ms (n = 13) and 170 +/- 19 ms (n = 4), at -90 and -100 mV]. Bupivacaine block of Kv4.3 channels was not stereoselective (KD approximately 31 microM). CONCLUSIONS: The functional profile of Kv4.3 channels expressed in Ltk- cells corresponds closely to rat ITO, although differences in recovery do not rule out association with accessory subunits. Nevertheless, the sustained component needs to be considered with respect to native ITO. (+info)
Analgesic infiltration at the site of bone marrow harvest significantly reduces donor morbidity.
(19/1144)
Little information has been published concerning the severity of pain experienced by bone marrow donors or the use of local analgesia following bone marrow harvesting procedures. The aims of this study were to assess duration and severity of pain experienced by bone marrow donors and the effectiveness of bupivacaine as a local analgesic agent following bone marrow harvest. During a single blinded randomised study of 24 bone marrow donors, 10 ml of 0.5% bupivacaine was infiltrated either into the right or left posterior iliac crest of the donor immediately following bone marrow harvest. Donors were requested to record the level of pain experienced at the right and left harvest sites on a pain rating score sheet (0-10) at time intervals of 4, 8, 12, 24, 48 and 72 h following harvest. A significant reduction in pain was experienced at the harvest site infiltrated with bupivacaine when compared with the control site during the first 3 days post-harvest. It is recommended that bupivacaine be infiltrated routinely into the harvest sites of all bone marrow donors to reduce the pain experienced in the 3 days following harvest. (+info)
Clinical effects and maternal and fetal plasma concentrations of 0.5% epidural levobupivacaine versus bupivacaine for cesarean delivery.
(20/1144)
BACKGROUND: Bupivacaine exists as a mixture of two enantiomers, levobupivacaine and dexbupivacaine. Data suggest that levobupivacaine has equal local anesthetic potency, with reduced potential for central nervous system and cardiovascular toxicity. The present study compares the efficacy of 0.5% levobupivacaine with 0.5% bupivacaine for epidural anesthesia in parturients undergoing elective cesarean delivery. METHODS: Sixty healthy obstetric patients undergoing elective cesarean delivery with epidural anesthesia completed the study. Patients were randomized to receive 30 ml of either 0.5% levobupivacaine or 0.5% bupivacaine in a double-blind fashion. The efficacy endpoint measures included onset, offset, and quality of anesthesia. Neonatal blood gas analyses, Apgar score determinations, and neurobehavioral examinations were performed. Venous samples for pharmacokinetic studies and serial electrocardiograms were obtained in 10 patients in each group. RESULTS: Levels of sensory block, motor block, muscle relaxation, and overall quality of anesthesia did not differ between groups. The frequency of hypotension was 84.4% in the levobupivacaine group and 100% for the bupivacaine group (P < or = 0.053). No significant difference in observed maximum concentration of drug after dosing or area under the plasma drug concentration versus time curve were seen. The maximum concentrations were 1.017 and 1.053 microg/ml, and the areas were 4.082 and 3.765 h(microg/ml) for the levobupivacaine and bupivacaine groups, respectively. Umbilical vein-to-maternal vein ratios were 0.303 for the levobupivacaine group and 0.254 for the bupivacaine group. CONCLUSIONS: The use of epidural 0.5% levobupivacaine for cesarean delivery results in equally efficacious anesthesia compared with 0.5% bupivacaine. Pharmacokinetic parameters were similar in the two groups. (+info)
The placental transfer and fetal effects of levobupivacaine, racemic bupivacaine, and ropivacaine.
(21/1144)
BACKGROUND: The purposes of this study were to assess the effects of levobupivacaine on uterine blood flow and fetal well-being and to compare its placental transfer with that of bupivacaine and ropivacaine. METHODS: After a control period, pregnant ewes that were fitted with instruments for long-term monitoring were randomized to receive a two-step intravenous infusion of levobupivacaine, bupivacaine, or ropivacaine, in a blinded manner, for 1 h. Maternal and fetal hemodynamics were monitored during the study. Arterial blood samples were drawn at 30 and 60 min of infusion from the mother and fetus to determine the acid-base status (60 min only) and serum drug concentrations. The fetal brain, heart, liver, lungs, adrenal glands, and kidneys were obtained to measure tissue drug levels. RESULTS: Maternal blood pressure, central venous and intraamniotic pressures, acid-base status and uterine blood flow were unaffected by any drug infusion. In contrast to the other two local anesthetics, the infusion of bupivacaine was associated with a small but significant decrease in the ewe's heart rate. At the end of the study, the heart rate in the bupivacaine-treated animals was significantly less than in the animals treated with the other two drugs. All fetuses were in good condition at the start of study, and none of the local anesthetics affected fetal well-being. No significant differences were found among the three drugs in the maternal serum, fetal serum, fetal tissue concentrations, and tissue:serum concentration ratios. CONCLUSIONS: Levobupivacaine was similar to bupivacaine and ropivacaine in causing no important hemodynamic changes in the pregnant ewe and fetus. There were no significant differences in the fetal serum and tissue levels of the drugs. (+info)
Respiratory effects of low-dose bupivacaine interscalene block.
(22/1144)
In this double-blind study, interscalene brachial plexus (ISBP) block was performed in 11 volunteers using 10 ml of either 0.25% (n = 6) or 0.5% (n = 5) bupivacaine with epinephrine 1:200,000. Diaphragmatic excursion, respiratory function and neural function were assessed for 90 min. Our results showed that hemidiaphragmatic excursion declined significantly after block in the 0.5% group and paradoxical movement during inspiration was more common than in the 0.25% group. Forced vital capacity and forced expiratory volume in 1 s declined significantly in the 0.5% group (mean 74.6 (SD 13.0)% and 78.2 (19.9)% of baseline, respectively) but not in the 0.25% group. Sensory anaesthesia in the upper limb was found consistently in both groups, although biceps paralysis occurred earlier after 0.5% bupivacaine. We conclude that ISBP block using 10 ml of 0.25% bupivacaine provided upper limb anaesthesia to pinprick in C5-6 dermatomes with only occasional interference with respiratory function. (+info)
Comparison of midwife top-ups, continuous infusion and patient-controlled epidural analgesia for maintaining mobility after a low-dose combined spinal-epidural.
(23/1144)
We studied 133 women given a combined spinal-epidural for analgesia in labour. The initial intrathecal dose contained bupivacaine 2.5 mg with fentanyl 25 micrograms. When the mothers were comfortable, they were allocated randomly to one of three groups: continuous infusion (group Cl, n = 46), midwife top-ups (group MW, n = 43) or patient-controlled epidural analgesia (group PCEA, n = 44), to maintain analgesia throughout labour. All epidural solutions contained 0.1% bupivacaine and fentanyl 2 micrograms ml-1. Motor block was assessed by the mother's ability to straight leg raise (SLR). Four hours after combined spinal-epidural analgesia, 88.1% of women could SLR in group MW, 83.7% in group PCEA and 57.8% in group Cl (P = 0.002). Total use of bupivacaine was highest in group Cl (mean 11.3 (SD 3.3) mg h-1) compared with group MW (7.5 (3.1) mg h-1) and group PCEA (9.1 (2.1) mg h-1) (P < 0.001). Analgesia was similar between groups and overall satisfaction was equally high. (+info)
Levobupivacaine vs bupivacaine as infiltration anaesthesia in inguinal herniorrhaphy.
(24/1144)
We have compared the anaesthetic and analgesic efficacy of levobupivacaine with that of racemic bupivacaine in 66 male patients undergoing ambulatory primary inguinal herniorrhaphy. Patients were allocated randomly in a double-blind manner to local infiltration anaesthesia (0.25% w/v 50 ml) with either racemic bupivacaine (n = 33) or levobupivacaine (n = 33). Scores for intraoperative pain and satisfaction with anaesthesia were recorded, together with perception of postoperative pain and need for supplementary postoperative analgesic medications in the first 48 h after operation. Intraoperative satisfaction with the infiltration anaesthesia was similar, with median scores of 77 (levobupivacaine) and 80 (bupivacaine) (VAS; 100 mm = extremely satisfied). Time averaged postoperative pain scores (48 h) were 8 (levobupivacaine) and 10 (bupivacaine) in the supine position, 13 (levobupivacaine) and 12 (bupivacaine) while rising from the supine position to sitting, and 9 (levobupivacaine) and 13 (bupivacaine) while walking (VAS; 100 mm = worst pain imaginable) (ns). There was no difference in the use of peroral postoperative analgesics between the two groups. We conclude that racemic bupivacaine and its S-enantiomer levobupivacaine had similar efficacy when used as local infiltration anaesthesia in inguinal herniorrhaphy. (+info)