Obstetric local anesthetic toxicity

Pain exhibits temporal variations in intensity due to multiple factors, including endogenous neuroendocrine and various external influences that vary over the 24 h. Also, medications can vary in potency and/or toxicity according to the time when they are administered. However, there is no consensus among studies regarding the 24-h pattern of analgesia during labor. Taking into account the time-of-day when labor analgesia is administered, this study aimed to answer two questions: (i) Is there diurnal variation in visual analogue scale (VAS)-rated pain relief and duration of intrathecal analgesia in patients undergoing labor analgesia? (ii) If there is, what is the influence of the duration of labor on the diurnal variation of the level of pain relief and duration of intrathecal analgesia? This prospective cohort included 41 healthy, nulliparous women in the first stage of labor undergoing spinal-epidural (CSE) analgesia using fentanyl combined with bupivacaine...

BACKGROUND: Ropivacaine and levobupivacaine have been introduced into obstetric analgesic practice with the proposed advantages of causing less motor block and toxicity compared with bupivacaine. However, it is still controversial whether both anesthetics are associated with any clinical benefit relative to bupivacaine for labor analgesia. This study aimed to compare the analgesic efficacy, motor block and side effects of bupivacaine, ropivacaine and levobupivacaine at lower concentrations for patient-controlled epidural labor analgesia...

BACKGROUND AND OBJECTIVES: Epidural 0.5% racemic bupivacaine associated with opioids is a technique used in cesarean sections; however, its toxicity has been questioned. 50% Enantiomeric excess bupivacaine has lower cardio- and neurotoxicity. The efficacy of epidural 0.5% racemic bupivacaine and 0.5% enantiomeric excess bupivacaine associated with sufentanil in parturients undergoing cesarean sections was evaluated. METHODS: Fifty gravida at term, undergoing elective cesarean section under epidural block, were divided in two groups according to the local anesthetic used: Group I - 0...

BACKGROUND: Epidural analgesia is the most effective for the control of pain during labor but irregularity of analgesia, toxicity of local anesthetics (LA) and driving block are the major limits of the modalities of maintenance. AIM: The purpose of this work was to assess the effectiveness and adverse effects of adaptations offered with Patient Controlled Epidural Analgesia (PCEA). METHODS: 40 mono-foetal parturients were randomized in two groups: 0...

There is evidence that administration of lipid emulsion improves outcome in cardiovascular collapse secondary to local anaesthetic toxicity. We sent a questionnaire to the lead consultant anaesthetist in every consultant-led labour ward in the UK asking about local guidelines for treatment of cardiac arrest, and whether or nor lipid emulsion was available on the labour ward and included in the guideline. We received replies from 195 (86%) labour wards. One hundred and seven (55%) reported having a guideline for the treatment of cardiovascular collapse secondary to local anaesthetic toxicity...

BACKGROUND: In comparison with bupivacaine, ropivacaine exhibits comparable anaesthetic effects but with less motor impairment and systemic toxicity. However, the analgesic potency may differ. For example, ropivacaine during obstetric epidural analgesia provides an approximately 40% lower analgesic potency than bupivacaine. Equal visual analogue pain scores require significantly higher dosages of ropivacaine, and general statements about a favourable benefit-risk profile relative to that of bupivacaine may therefore have limited clinical impact...

BACKGROUND: In this study we sought to determine and compare the minimum local anesthetic volumes (MLAV) and doses (MLAD) of two concentrations of bupivacaine for epidural pain relief in labor, and to quantify the effect on dose. METHODS: Eighty women were randomized in a double-blind manner to receive a first bolus of either plain bupivacaine 0.125% (w/v) or 0.25% (w/v). The arbitrary starting volume was 15 mL. Subsequent volumes were decided by sequential allocation according to analgesic efficacy...

BACKGROUND: This study evaluated efficacy, safety and patient satisfaction with incisional analgesia with a subfascial catheter compared to epidural analgesia for pain relief following caesarean section. METHODS: Forty patients were randomised after elective caesarean section to receive either intermittent 10-mL boluses of 0.125% levobupivacaine into the epidural space and physiologic saline into the surgical wound or intermittent 10-mL boluses of 0.25% levobupivacaine into the wound and epidural saline with a repeated 10-dose regimen...

BACKGROUND: When extending a fentanyl-containing, low-dose labour epidural for emergency caesarean section it has been shown that there is no difference in time to surgical readiness between plain bupivacaine 0.5% and mixtures of lidocaine/epinephrine or lidocaine/bupivacaine/epinephrine. However, it is not known whether adding fentanyl to the lidocaine/epinephrine mixture would increase speed of onset or improve the efficacy of the mixture when topping up for an emergency caesarean section...

BACKGROUND AND OBJECTIVES: Bupivacaine is available as a racemic mixture of dextrobupivacaine and levobupivacaine. Many studies show that dextrobupivacaine has a greater inherent central nervous system and cardiovascular toxicity than levobupivacaine. The aim of the present study was to investigate the clinical efficacy and safety of levobupivacaine compared with racemic bupivacaine for extradural anesthesia. METERIAL AND METHOD: The authors studied 61 patients undergoing elective cesarean delivery who received either 0...

OBJECTIVE: To study the effects of a 4% intrauterine lidocaine infusion on perceived patient pain in first-trimester abortions. METHODS: A randomized, double-blind, placebo-controlled trial of 80 women receiving either a 5-mL 4% lidocaine (n = 40) or saline (n = 40) intrauterine infusion and a standard paracervical block before first-trimester abortion. Women completed a series of 100-mm visual analog scales (anchors: 0 = none, 100 mm = worst imaginable) to measure their perceived pain (anticipated pain, after speculum insertion, after intrauterine infusion, after cervical dilation, after suction aspiration, and 30 minutes postprocedure)...

BACKGROUND: Several studies have been performed to find a safe method of labor analgesia with minimal side effects and toxicity in mother and fetus. We aimed to compare the efficacy and side effects of epidural bupivacaine plus fentanyl and ropivacaine plus fentanyl at low concentrations. METHOD: Forty ASA I-II parturients' were included in this prospective, double-blind, trial and randomized to receive either bupivacaine or ropivacaine for labor analgesia. Analgesia was initiated with 8 mL of 0...

Ropivacaine (Naropin, AstraZeneca) a new long-acting amide local anaesthetic agent, is a pure S-enantiomer, with a high pKa and relatively low-lipid solubility. Since its clinical introduction in 1996, it has been the focus of intense interest because of its increased CNS and cardiovascular safety compared with bupivacaine. This article reviews the pharmacology of ropivacaine with particular emphasis placed on toxicological issues. Compared with bupivacaine (the drug of choice for many years), ropivacaine is equally effective for subcutaneous infiltration, epidural, intrathecal and peripheral nerve block surgery, and obstetrics and postoperative analgesia...

We report a case of painful carpo-pedal spasm associated with the initiation of epidural analgesia for labor. The patient, an otherwise healthy primigravida in early labor at term, was experiencing severe hyperventilation as a result of inappropriate use of the Lamaze breathing technique. Bilateral carpo-pedal spasm occurred, and produced severe pain. Resolution of symptoms coincided with onset of effective epidural labor pain relief. A diagnostic challenge was presented to the anesthesiologist, as the symptoms could have been consistent with subdural block, local anesthetic toxicity, high sensory level of analgesia or eclamptic neuro-excitation activity...

Ropivacaine is a long-acting amide-type local anaesthetic, released for clinical use in 1996. In comparison with bupivacaine, ropivacaine is equally effective for subcutaneous infiltration, epidural and peripheral nerve block for surgery, obstetric procedures and postoperative analgesia. Nevertheless, ropivacaine differs from bupivacaine in several aspects: firstly, it is marketed as a pure S(-)-enantiomer and not as a racemate, and secondly, its lipid solubility is markedly lower. These features have been suggested to significantly improve the safety profile of ropivacaine, and indeed, numerous studies have shown that ropivacaine has less cardiovascular and CNS toxicity than racemic bupivacaine in healthy volunteers...

Levobupivacaine, the S-enantiomer of racemic bupivacaine, will be available in Germany in mid-2004. Pharmacological studies demonstrated that, compared to bupivacaine, levobupivacaine has equal local anaesthetic potency with reduced potential for cardiac and CNS toxicity. This review introduces the new long-acting amide local anaesthetic levobupivacaine to the reader and evaluates its place in obstetric analgesia and anaesthesia compared to bupivacaine and ropivacaine.

OBJECTIVE: To compare the analgesic efficacy, pharmacokinetics and histamine release of ropivacaine and bupivacaine with fentanyl in continuous epidural perfusion during labor and childbirth. MATERIAL AND METHODS: Prospective study of 40 women at full-term pregnancy who requested epidural analgesia. The patients were randomly assigned to 2 groups of 20: group R received an initial bolus dose of 10 mL of 0.25% ropivacaine and group B received 0.25% bupivacaine, followed in both groups by epidural infusion of the assigned drugs at a concentration of 0...

OBJECTIVE: To study the effects of an intrauterine lidocaine infusion on perceived patient pain in first-trimester abortions and to measure serum lidocaine levels. METHODS: A randomized, double-blind, placebo control trial of 80 women receiving either a 10-mL 1% lidocaine (n = 40) or saline (n = 40) intrauterine infusion and a standard paracervical block before first-trimester abortion was undertaken. Women completed a series of 100-mm visual analogue scales to measure their perceived pain (anticipated pain, after speculum insertion, after intrauterine infusion, after cervical dilation, after suction aspiration, and 30 minutes after procedure)...

BACKGROUND AND OBJECTIVES: Bupivacaine is available as a racemic mixture of its enantiomers, dextrobupivacaine and levobupivacaine. Both in vitro and in vivo studies show that dextrobupivacaine has a greater inherent central nervous system (CNS) and cardiovascular toxicity than levobupivacaine. Clinical studies show levobupivacaine to have similar local anesthetic potency to the racemate. The aim of this study was to investigate the clinical efficacy and safety of levobupivacaine compared with racemic bupivacaine for extradural anesthesia...

For a long time, epidural anaesthesia has been considered the method of choice for Caesarean delivery. The increased incidence of hypotension by the rapid onset of sympathetic blockade under spinal anaesthesia has been associated with a decline in uteroplacental blood flow and significant fetal acidosis, which may compromise neonatal well-being. Nevertheless, a decrease in fetal pH has not been shown to reduce neonatal Apgar or neurobehavioural assessment scores. Maternal blood pressure can be preserved with little side effects with low doses of vasopressors...