PURPOSE: Intravenous lipid emulsions have been used to treat the systemic toxicity of local anesthetics. The goal of this in vitro study was to examine the effects of lipid emulsions on the norepinephrine-mediated reversal of vasodilation induced by high doses of levobupivacaine, ropivacaine, and mepivacaine in isolated endothelium-denuded rat aorta, and to determine whether such effects are associated with the lipid solubility of local anesthetics. MATERIALS AND METHODS: The effects of lipid emulsions (0.30, 0.49, 1.40, and 2.61%) on norepinephrine concentration-responses in high-dose local anesthetic (6x10-4 M levobupivacaine, 2x10-3 M ropivacaine, and 7x10-3 M mepivacaine)-induced vasodilation of isolated aorta precontracted with 60 mM KCl were assessed. The effects of lipid emulsions on local anesthetic- and diltiazem-induced vasodilation in isolated aorta precontracted with phenylephrine were also assessed. RESULTS: Lipid emulsions (0.30%) enhanced norepinephrine-induced contraction in levobupivacaine-induced vasodilation, whereas 1.40 and 2.61% lipid emulsions enhanced norepinephrine-induced contraction in both ropivacaine- and mepivacaine-induced vasodilation, respectively. Lipid emulsions (0.20, 0.49 and 1.40%) inhibited vasodilation induced by levobupivacaine and ropivacaine, whereas 1.40 and 2.61% lipid emulsions slightly attenuated mepivacaine (3x10-3 M)-induced vasodilation. In addition, lipid emulsions attenuated diltiazem-induced vasodilation. Lipid emulsions enhanced norepinephrine-induced contraction in endothelium-denuded aorta without pretreatment with local anesthetics. CONCLUSION: Taken together, these results suggest that lipid emulsions enhance the norepinephrine-mediated reversal of local anesthetic-induced vasodilation at toxic anesthetic doses and inhibit local anesthetic-induced vasodilation in a manner correlated with the lipid solubility of a particular local anesthetic.
Amides/adverse effects ; Anesthetics, Local/*adverse effects ; Animals ; Bupivacaine/adverse effects/analogs & derivatives ; Emulsions/*chemistry/*therapeutic use ; Lipids/*chemistry ; Male ; Mepivacaine/adverse effects ; Norepinephrine/*therapeutic use ; Rats ; Rats, Sprague-Dawley ; Vasodilation/*drug effects

OBJECTIVETo compare efficacy and side effects of patient-controlled epidural analgesia (PCEA) with levobupivacaine, ropivacaine and racemic bupivacaine after cesarean section.

METHODSIn this prospective, randomized double-blind study, 90 ASA I-II full-term nulliparous women (aged 25-38 years with body weight of 59-87 kg) undergoing elective cesarean section under spinal-epidural anesthesia equally allocated into 3 groups. PCEA was administered with 0.125% levobupivacaine and 20 microg/ml morphine (group L, n=30), 0.125% ropivacaine and 20 microg/ml morphine (group R, n=30), and 0.125% bupivacaine and 20 microg/ml morphine (group B, n=30), respectively. The Visual Analog Scale (VAS) score, satisfaction rate, patients' overall impression of treatment, modified Bromage motor score, and incidence of side effects were recorded at regular intervals after operation.

RESULTSThe three groups were comparable with respect to the efficacy of analgesia, patients' overall impression of treatment, motor blockade and side effects. There was significant difference in patients' satisfaction rate between group R (70%) and the other two groups (93.3% in group L and 96.6% in group B, P<0.05).

CONCLUSIONPCEA with 0.125% levobupivacaine and morphine 20 microg/ml produces better analgesic effect with little side effects after cesarean section.

Adult ; Amides ; administration & dosage ; adverse effects ; Analgesia, Epidural ; Analgesia, Obstetrical ; Analgesia, Patient-Controlled ; Bupivacaine ; administration & dosage ; adverse effects ; analogs & derivatives ; Cesarean Section ; Double-Blind Method ; Drug Therapy, Combination ; Female ; Humans ; Morphine ; administration & dosage ; Nausea ; chemically induced ; Pregnancy ; Prospective Studies ; Pruritus ; chemically induced ; Treatment Outcome ; Vomiting ; chemically induced

Although levobupivacaine (LBUP) is less cardiotoxic than racemic bupivacaine (RBUP), the resuscitation from the LBUP-induced cardiovascular collapse (CVC) has not been easy as expected. Following the recent reports that proposed the resuscitative action of insulin for the RBUP-induced CVC, a controlled trial was performed to assess the feasibility of insulin for the LBUP-induced CVC. Fourteen dogs were randomly allocated into two groups: the RBUP and LBUP groups. Each group received continuous intravenous infusions of RBUP or LBUP until the mean arterial pressure (MAP) reached 40 mmHg. Then, an intravenous bolus of insulin (2 U/kg) was administered. Both groups were successfully resuscitated. At CVC, a decrease of cardiac output and an increase of systemic vascular resistance were observed but to a lesser degree in the LBUP group (p<0.05). After insulin injection, the MAP further declined to under 40 mmHg for several minutes, which was more protracted in the LBUP group (p<0.05). The CVCs induced by LBUP or RBUP in anesthetized dogs could be successfully resuscitated by insulin. Compared with RBUP, however, the less degree of vasoconstriction by LBUP and the innate vasodilatory property of insulin yielded a delayed increment of MAP during the immediate resuscitation period in the LBUP-induced CVC.
Treatment Outcome ; Overdose ; Male ; Insulin/*administration & dosage ; Heart Arrest/*chemically induced/physiopathology/*prevention & control ; Drug Combinations ; Dose-Response Relationship, Drug ; Dogs ; Cardiopulmonary Resuscitation/methods ; Cardiac Output/*drug effects ; Bupivacaine/*adverse effects/analogs & derivatives ; Blood Pressure/*drug effects ; Blood Flow Velocity/drug effects ; Animals ; Anesthetics, Local