Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Comparative Study Clinical TrialRopivacaine 0.15% plus sufentanil 0.5 microg/mL and ropivacaine 0.10% plus sufentanil 0.5 microg/mL are equivalent for patient-controlled epidural analgesia during labor.
We compared the administration of 0.15% ropivacaine plus 0.5 microg/mL of sufentanil with that of 0.10% ropivacaine plus 0.5 microg/mL of sufentanil for labor analgesia with patient-controlled epidural analgesia (PCEA) to determine whether a decreased concentration of ropivacaine could produce equally effective analgesia. One-hundred-thirty healthy pregnant women at term were randomized in a double-blinded fashion. The PCEA settings were as follows: 12-mL initial bolus, 5-mL bolus dose, 5-min lockout interval, and 10 mL/h basal infusion. Patient demographics and labor characteristics were comparable in both groups. No differences were observed for pain scores, maternal satisfaction, volume of anesthetic solution administered, number of boluses requested and delivered, need for supplemental boluses, mode of delivery, motor block, side effects, or Apgar scores. Patients in the 0.10% ropivacaine group used significantly less drug than those in the 0.15% group (mean, 57 mg; 95% confidence interval, 50.5-63.5 mg; versus mean, 88.0 mg; 95% confidence interval, 74.4-93.3 mg, respectively; P < 0.0001). Ropivacaine 0.10% plus 0.5 microg/mL of sufentanil administered via PCEA for labor analgesia is equally effective as ropivacaine 0.15% plus 0.5 microg/mL of sufentanil, with a 30% local anesthetic-sparing effect and a 40% reduction in cost. However, this reduction in local anesthetic is not associated with a decrease in the incidence of motor block, side effects, or instrumental deliveries. ⋯ Ropivacaine 0.10% plus 0.5 microg/mL of sufentanil given via patient-controlled epidural anesthesia for labor analgesia is equally as effective as ropivacaine 0.15% plus 0.5 microg/mL of sufentanil, with a 30% local anesthetic-sparing effect and a 40% reduction in cost. This reduction in ropivacaine concentration is not associated with a decrease in the incidence of motor block, side effects, or instrumental deliveries.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialMinimum analgesic doses of fentanyl and sufentanil for epidural analgesia in the first stage of labor.
In this study, we sought to determine the minimum analgesic doses and relative potencies of fentanyl and sufentanil when they are used as the sole epidural analgesic during the first stage of labor. Nulliparous parturients (n = 66) in spontaneous labor at term gestation and requesting epidural analgesia were enrolled into this prospective, double-blinded, randomized, sequential-allocation study. Each woman received fentanyl or sufentanil diluted with 0.9% wt/vol saline to a volume of 10 mL. The initial dose was arbitrarily chosen to be 125 microg for fentanyl and 25 microg for sufentanil, with subsequent doses being determined by the response of the previous patient (testing interval, 5 microg for fentanyl and 1 microg for sufentanil). Efficacy was accepted if the visual analog score decreased to < or =10 mm on a 100-mm scale within 30 min. The minimum analgesic dose or median effective dose was 21.1 microg (95% confidence interval [CI], 20.2-21.9 microg) for sufentanil and 124.2 microg (95% CI, 118.1-130.6 microg) for fentanyl (P < 0.0001). The sufentanil/fentanyl potency ratio was 5.9 (95% CI, 5.6-6.3). In conclusion, we have established the equivalent doses and relative potencies of fentanyl and sufentanil for epidural analgesia in the first stage of labor. ⋯ This study determined the minimum analgesic doses of fentanyl and sufentanil for epidural anesthesia in the first stage of labor. The sufentanil/fentanyl potency ratio was 5.9. This ratio may be used to establish the equivalent doses for fentanyl and sufentanil for epidural analgesia in labor.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialThe effect of epidural test dose on motor function after a combined spinal-epidural technique for labor analgesia.
Labor analgesia initiated with intrathecal bupivacaine and fentanyl, without a local anesthetic epidural test dose, provides effective analgesia and allows ambulation. In this study, we sought to determine the effect of a lidocaine-epinephrine test dose administered immediately after the initiation of combined spinal-epidural (CSE) analgesia with bupivacaine 2.5 mg and fentanyl 25 micro g on parturients' hemodynamic stability, posterior column function, motor strength, and subjective ability to walk. Parturients (n = 153) were randomized to receive either 3 mL of epidural saline or lidocaine 1.5% with epinephrine 1:200,000. Hemodynamic variables, proprioception, straight leg raise, and the modified Bromage score were analyzed in 110 parturients who completed the study protocol and were not different between groups. Vibratory sense, the ability to perform a partial deep knee bend and to step up on a stool, and the subjective ability to walk were impaired in a larger number of parturients in the lidocaine-epinephrine group at 30 min (P < 0.05). At 60 min, there were no differences between the groups except that fewer parturients in the lidocaine-epinephrine group could step up on a stool. The straight leg raise against resistance and the modified Bromage scale did not correlate well with other tests of motor strength (Spearman's rho, 0.273-0.405). These data suggest that the test dose should be avoided immediately after initiation of CSE analgesia when early ambulation is desired. ⋯ A lidocaine-epinephrine epidural test dose (3 mL of lidocaine 1.5% with epinephrine 1:200,000), injected immediately after the initiation of combined spinal-epidural labor analgesia with bupivacaine 2.5 mg and fentanyl 25 microg, may interfere with the ability to perform simple tests of motor function and ambulation.
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Anesthesia and analgesia · Apr 2003
Clinical TrialThe effect of epidural neostigmine combined with ropivacaine and sufentanil on neuraxial analgesia during labor.
Spinal neostigmine produces analgesia without respiratory depression or hypotension but provokes major gastrointestinal side effects. Epidural injection of this drug, however, appears to induce analgesia devoid of such side effects. In this study, we evaluated the effect of a bolus of epidural neostigmine on the duration and magnitude of analgesia in early labor and assessed its eventual sparing effect on subsequent local anesthetic requirements. Epidural neostigmine methylsulfate (maximal dose 4 microg/kg) was added to 10 mL of ropivacaine 0.1%, with and without sufentanil 10 microg, to initiate analgesia. Twenty minutes after injection, pain score, sensory level, and motor block were assessed. Time until request for supplemental epidural medication was also recorded. Patient-controlled epidural analgesia with ropivacaine 0.1% was used for epidural supplementation. Maternal and fetal side effects were closely recorded. Neostigmine (4 microg/kg), when added to ropivacaine 10 mg, provided equivalent analgesia to ropivacaine 20 mg but was less effective than sufentanil 10 microg for the initiation of labor epidural analgesia. Further, neostigmine did not modify the subsequent patient-controlled epidural analgesia local anesthetic requirements during labor. No hemodynamic instability, additional motor block, or bothersome side effects were recorded. ⋯ The combination of epidural neostigmine (4 microg/kg) with the local anesthetic ropivacaine, with or without sufentanil, does not significantly enhance neuraxial analgesia during labor. Such a dose, however, has no bothersome side effects.
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Anesthesia and analgesia · Apr 2003
Comparative StudyThe comparative effects of prostaglandin E1 and nicardipine on cerebral microcirculation in rabbits.
We compared the effects of the systemic hypotensive drugs prostaglandin E1 (PGE1) and nicardipine on the cerebral microcirculation and on the cerebrovascular reactivities to hypercapnia and hypoxia. In isoflurane-anesthetized rabbits (n = 48), we measured cerebral pial vessel diameters using a cranial-window preparation: (a) during IV PGE1- or nicardipine-induced mild or moderate hypotension (to 80% or 60% of initial mean arterial blood pressure), (b) after topical administration of these drugs, and (c) during hypercapnia or hypoxia induced during such mild or moderate hypotension. Pial arteriolar diameters were (a) unchanged when hypotension (mild or moderate) was induced by PGE1 but increased when it was induced by nicardipine and (b) increased dose-dependently by topical administration of nicardipine but not PGE1. Only small changes in cerebral venular diameter were observed in these experiments. The pial arteriolar dilator response to hypercapnia was potentiated during hypotension (mild or moderate) when it was induced by PGE1 but decreased when it was induced by nicardipine, whereas the response to hypoxia was maintained during PGE1-induced hypotension but decreased during nicardipine-induced hypotension. In conclusion, as a systemic hypotensive drug, PGE1 does not dilate cerebral arterioles and maintains cerebrovascular reactivities to hypercapnia and hypoxia, whereas nicardipine dilates such vessels and reduces these cerebrovascular reactivities. ⋯ When given systemically to produce mild or moderate hypotension, prostaglandin E1 does not induce cerebral vasodilation and maintains cerebrovascular reactivity to hypercapnia and hypoxia, whereas nicardipine dilates cerebral vessels and reduces both reactivities.