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INTRODUCTION OF TWO NEW ANESTHETIC AGENTS. Dr.G.k.kumar. Ropivacaine Dexmeditomedine. Ropivacaine. Ropivacaine. New local anesthetic agent Introduced in 1996. In India 2009. Ropivacaine. Lower systemic toxicity Safest long acting local anesthetic agent.
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INTRODUCTIONOF TWO NEW ANESTHETIC AGENTS Dr.G.k.kumar
Ropivacaine • New local anesthetic agent • Introduced in 1996. • In India 2009.
Ropivacaine • Lowersystemictoxicity • Safest long acting local anesthetic agent. *Groban et al. Anesth Analg, 2001. Ohmura et al. Anesth Analg, 2001. Santos et al. Anesthesiology, 2001.
Ropivacaine-Pharmacology • Long acting LA agent. • Aminio amide. • Pure enantiomer -S isomer.
Ropivacaine-Pharmacology • Greaterselectivity for sensoryblockade -bindsselectively to Na⁺channels 1.7 • Shorter motor block *Liu BG et al, AnesAnalg.2000May. Simpsons D et al,2005
Ropivacaine-Pharmacology • Ropivacaine is less lipid soluble. • A smaller volume of distribution. • Greater clearance. • Shorter elimination half-life than bupivacaine. • -Shorter duration of action esp motor blockade – early recovery.
Ropivacaine-Pharmacology • Ropivacaine undergoes hepatic biotransformation and renal excretion • Excreted 86% as metobolites • Safe in CESLD & CESRD *Jokinen MJ et al, Anesthesiology,2007Jan. Jokinen MJ et al,Clinical Anesthesiology,2005
Ropivacaine-Pharmacology • The specific gravity of Ropivacaine Injection -from 1.002 to 1.005 at 25°C. -Isobaric
Ropivacine-Safe Dose • 3-5mg /kg. • Pediatric-1-2mg/kg
Ropivacaine-Epidural dose *Miller’s anesthesia,7th edition
Ropivacaine-Spinal dose *Miller’s anesthesia,7th edition
Ropivacaine – clinical efficacy • When used for spinal anesthesia, 0.75% ropivacaine produces less intense sensory and motor block than 0.5% bupivacaine. • Equipotent to bupivacaine when used for lumbar epidural labor analgesia and C-section.
Ropivacaine – clinical efficacy • In epidural and other blocks bupivacaine and ropivacaine demonstrate similar intensity of sensory anesthesia.
Ropivacaine – clinical efficacy • Ropivacaine motor block -delayed in onset. -less intense. -shorter in duration.
Toxicity • Ropivacaine < Levobupivacaine < Bupivacaine • Even at 50% higher dosage!!! *Dony et al. Anesth Analg, 2000
Toxicity • Tolerated blood conc. level [ROP] >> [BUP] = [LBUP] • Mortality: BUP (50%) > LBUP (30%) > ROP (10%) • * Groban et al. Anesth Analg, 2001. • Ohmura et al. Anesth Analg, 2001. • Santos et al. Anesthesiology, 2001.
Ropivacine-WhySaferThanBupivacaine? • Bupivacaine is a 50:50 racemic mixture of the S- and R-enantiomers. • The R isomer has greater affinity and binding time for voltage-gated sodium channels, and so cardiotoxicity.
Ropivacine-WhySaferThanBupivacaine? • R-bupivacaine is also more arrhythmogenic. • Slows ventricular conduction 4.6 times as much as S-bupivacaine.
Ropivacine-WhySaferThanBupivacaine? • The Ropivacaine is the pure S-enantiomer so decreased cardiotoxicity .
Ropivacine-WhySaferThanBupivacaine? • Cumulative doses up to 770 mg over 24 hours (intraoperative block plus postoperative infusion) • Continuous epidural infusion at rates up to 28 mg per hour for 72 hours have been well tolerated in adults, ie, 2016 mg plus surgical dose of approximately 100-150 mg as top-up. *www.fda druginformation.com
Ropivacine-WhySaferThanBupivacaine? • Ropivacaine has a larger therapeutic index • 70% less likely to cause severe cardiac dysarrhythmias • Greater CNS tolerance • The improved safety profile is due to a lower lipid solubility
Ropivacaine HYPE? HOPE?
LA toxicity more in • Heart block, HT, structural heart disease. • >65yr,<12yr. • Pregnancy. • Acidosis. • Liver dysfunction. • Acutely ill and debilitated.
Role of Ropivacaine • SAFE PRACTICE • Pediatric patients. • Geriatric patients. • Continuous infusions. • For labour analgesia. • Rescue spinal anesthesia.
LA toxicity treatment • Supportive care: intubation, vasopressors, appropriate defibrillation, fluids, stop injection of LA. • Intralipid…Bolus 1cc/kg of 20% intralipid, 0.25cc/kg/min of 20% intralipid for 10 minutes • Bolus can be repeated every 5 minutes up to a maximum of 8cc/kg of 20% intralipid
LA toxicity treatment • Cardiac support should be continued as ACLS dictates • Adrenaline and vasopressin are usefull.