Ropivacain là gì? Các công bố khoa học về Ropivacain

Ropivacaine is a new amide local anesthetic, having therapeutic properties similar to those of bupivacaine but with a wider margin of safety. Bupivacaine is probably the most commonly used drug in obstetric epidural analgesia, even though laboratory studies have suggested that pregnancy increases the cardiotoxicity of bupivacaine but not of other local anesthetics. The current study was designed to reevaluate, in a random and blinded fashion, the systemic toxicity of bupivacaine and ropivacaine in nonpregnant and pregnant sheep.

Chronically prepared nonpregnant and pregnant ewes were randomized to receive an intravenous infusion of ropivacaine or bupivacaine at a constant rate of 0.5 mg.kg-1.min-1 until circulatory collapse. The investigators were blinded to the identity of local anesthetic. Heart rate, arterial blood pressure, and cardiac rhythm were monitored throughout the study. Arterial blood samples were obtained before infusion and at the onset of toxic manifestations, which appeared in the following sequence: convulsions, hypotension, apnea, and circulatory collapse. Serum drug concentrations and protein binding were determined. Blood pH and gas tensions were measured.

There were no significant differences between non-pregnant and pregnant animals in the doses or serum concentrations of either drug required to elicit toxic manifestations. In nonpregnant animals, similar doses and serum concentrations of ropivacaine and bupivacaine were associated with the onset of convulsions and circulatory collapse. In pregnant ewes, greater doses of ropivacaine as compared to bupivacaine were required to produce convulsions (7.5 +/- 0.5 vs. 5.0 +/- 0.6 mg.kg-1) and circulatory collapse (12.9 +/- 0.8 vs. 8.5 +/- 1.2 mg.kg-1). The corresponding serum concentrations of ropivacaine were similar to those of bupivacaine. Pregnancy did not affect the serum protein binding of either drug. The proportion of animals manifesting a malignant ventricular arrhythmia as the terminal event was similar among all groups.

The systemic toxicity of ropivacaine or bupivacaine is not enhanced by gestation in sheep. This is in contrast to an earlier study in which the cardiotoxicity of bupivacaine was enhanced during ovine pregnancy. Greater doses of ropivacaine, as compared to bupivacaine, are needed to produce toxic manifestations in pregnant animals.

The efficacy of local anesthetic wound infiltration for the treatment of acute and chronic postoperative pain is controversial and there are no detailed studies. The primary objective of this study was to evaluate the influence of ropivacaine wound infiltration on chronic pain after breast surgery.

In this prospective, randomized, double-blind, parallel-group, placebo-controlled study, 236 patients scheduled for breast cancer surgery were randomized (1:1) to receive ropivacaine or placebo infiltration of the wound, the second and third intercostal spaces and the humeral insertion of major pectoralis. Acute pain, analgesic consumption, nausea and vomiting were assessed every 30 min for 2 h in the postanesthesia care unit and every 6 h for 48 h. Chronic pain was evaluated 3 months, 6 months, and 1 yr after surgery by the brief pain inventory, hospital anxiety and depression, and neuropathic pain questionnaires.

Ropivacaine wound infiltration significantly decreased immediate postoperative pain for the first 90 min, but did not decrease chronic pain at 3 months (primary endpoint), or at 6 and 12 months postoperatively. At 3 months, the incidence of chronic pain was 33% and 27% (P = 0.37) in the ropivacaine and placebo groups, respectively. During follow-up, brief pain inventory, neuropathic pain, and anxiety increased over time in both groups (P < 0.001) while depression remained stable. No complications occurred.

This multicenter, prospective study shows that ropivacaine wound infiltration after breast cancer surgery decreased immediate postoperative pain but did not decrease chronic pain at 3, 6, and 12 months postoperatively.

Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function.

Healthy parturient women with singleton, uncomplicated pregnancies at term received 115-140 mg 0.5% ropivacaine (n = 11) or 0.5% bupivacaine (n = 10) in incremental epidural doses. The first ultrasound measurement was performed before injection of the study drug. Pulsatility indexes (PI) were derived for the blood flow velocity waveforms of the maternal placental and nonplacental uterine arteries; the placental arcuate artery; and the fetal umbilical, middle cerebral, and renal arteries. The fetal heart then was examined by echocardiography. The PI of the maternal uterine arteries and the fetal umbilical artery were measured 5 min after the injection of the local anesthetic. When sensory analgesia had reached the T6-T4 level, the ultrasound measurement was repeated with the same methods and targets as in the baseline measurement.

Both drugs provided adequate surgical anesthesia for cesarean section. In the bupivacaine group, the PI values for the maternal placental and nonplacental uterine arteries increased significantly 5 min after the main dose (P = 0.01, P = 0.002) and when sensory analgesia had reached the T6-T4 level (P = 0.004, P = 0.01) as compared with the baseline measurement. Simultaneously, the PI in the fetal middle cerebral artery decreased significantly (P = 0.02). The PI for the maternal uterine artery increased significantly (P = 0.01) after ropivacaine administration but only on the nonplacental side and not until sensory analgesia had reached the T6-T4 level. No effect on the Doppler indexes obtained from the umbilical artery was observed in either group. There were no significant differences relative to baseline values in any fetal myocardial measurement or in any ultrasound measurement between the groups. Neither drug had any detrimental effect on Apgar scores or umbilical cord acid-base status. None of the neonates' conditions was markedly depressed according to neurobehavioral testing.

Within this small study, epidural 0.5% ropivacaine for cesarean section did not compromise the utero-placental circulation in healthy parturient women with uncomplicated pregnancies. It provided surgical anesthesia that was equally effective as that provided by 0.5% bupivacaine.