IV anesthetic

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IV anesthetic

  1. 1. Intraveous anesthetics<br />Dr.Hussam Alsharani Dr.Osama Ibrahim<br />Anesthesia resident Assistant professor<br />Anesthesia d. KKUH Anesthesia d. KKUH<br />
  2. 2. Ideal IV anesthetics:<br />1-Drug compatibility (water solubility) and stability in solution.<br />2-lake pain on injection , veno irritation , and local tissue damage.<br />3-low potential to release histamine.<br />4-rabid and smooth onset of action without excitatory activity.<br />5-rabid metabolism to inactive metabolites.<br />6-a steep dose to minimize titratability and tissue accumulation.<br />7-lake of acute cardiovascular and respiratory depression.<br />8-decrease in cerebral metabolism and intracranial pressure.<br />9-rabid and smooth return to consciousness .<br />10-abcense of post operative nausea , vomiting, amnesia , psychoimetic reaction , dizziness , headache , and prolonged sedation.<br />
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  4. 4. Pharmacokinetics:<br />Anesthesia is produced by diffusion of drug from arterial blood across the blood brain barrier in to the brain which regulated by the following factors:<br />-protein binding: unbound drug is free to cross BBB.<br />-blood flow to the brain.<br />-extracellular PH and Pka of the drug: nonionized.<br />-solubility of the drug in lipid and water: high lipid<br /> solubility enhances transfer in to the brain.<br />-speed of injection.<br />
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  6. 6. Barbiturates (Thiopental):<br />-available as sodium salts (yellowish powder).<br />-bitter taste + smell of garlic.<br />-solution of thiobarbiturates are stable for 2 weeks.<br />-ph of solution of thiopental (2.5%) is 9.<br />-does not cause pain on injection.<br />-metabolized in liver to hydroxythiopental and <br /> carboxylic acid.<br />-produce anesthesia in less than 30 sec after iv injection.<br />-induction dose: 3-5 mg/kg in adults<br /> 5-6 mg/kg in children<br /> 6-8 mg/kg in infants<br />-recovery after 10 min<br />
  7. 7. -produce decrease in CPF there by lowering ICP.<br />-widely used to improve brain relaxation during<br /> neurosurgery and to improve cerebral infusion pressure <br /> after acute brain injury<br />-It cause dose dependent anticonvulsant activity.<br />-dose dependent respiratory depression.<br />-it cause decrease in cardiac output and ABP.<br />-early absence in eyelidreflex.<br />
  8. 8. -tissue necrosis: median nerve damage may be occur <br /> after extravenous injection in the antecubital fossa<br /> if perivenous injection occurred the needle should be <br /> left in place and injection of hyaloronidase.<br />-intra-arterial injection: pt usually complains of burning<br /> pain + intense in this case:<br /> -stop injection.<br /> -leave needle in artery.<br /> -administrate papaverine 20 mg.<br /> -heparin should be given iv and orally.<br /> -stellate ganglion or brachial plexus block<br /> may reduce arterial spasm.<br />
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  11. 11. Propofol:<br />-(2,6-dispropylphenol).<br />-pain on injection 32-67% of patients.<br />-t1/2 is 1-8 min (Barash 2009).<br />-elimination half time 2-24 min.<br />-metabolized in liver to sulfate and glucuronic acid which <br /> are eliminated by kidney.<br />-extra hepatic rout of elimination by lungs.<br />-anesthesia is induced in 20-40 sec after iv administration.<br />-we can monitor the onset by loss of verbal contact.<br />-induction dose 1.5 – 2.5 mg/kg.<br />-children require bigger dose.<br />-euphoria effect.<br />
  12. 12. -propofol decrease CPF and ICP.<br />-excitatory motor activity without EEG changes.<br />-dose and concentration dependent cardiovascular depression.<br />-dose dependent respiratory depression with apnea.<br />-antiemetic effects (10-20 mg to treat nausea and emesis<br /> in the early post operative period.<br />-antidopamenergic which lead to euphoria.<br />-it decrease the pruritus produced by spinal opioids.<br />-agent of choice in malignant hyperthermia suspictable pt.<br />-Propofol syndrome : after high dose infusion of propofol<br /> for long time – myocardial failure – metabolic acidosis –<br /> rabdomyolysis.<br />
  13. 13. Propofol has no effect on bronchial muscle tone and laryngospasm is particularly uncommon .<br />The suppression of laryngeal reflex and low incidence of coughing or laryngospasm when a laryngeal mask airway (LMA) is introduced , and propofol is regarded by most anesthetists as the drug of choice for induction of anesthesia when LMA is to be used.<br />
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  15. 15. Etomidate:<br />-carboxylated imidazole.<br />-ph 6.9 , pain on injection , venoirritation.<br />-induction dose : 0.2-0.3 mg/kg.<br />-involuntary myoclonic movement are common at induction.<br />-metabolism in liver.<br />-it decrease CPF and ICP.<br />-inhibitory effect on adrenocortical synthetic function (5-8 h<br /> after single use)<br />-inhibit platelet function.<br />-minimal cardiorespiratory depression .<br />-does not induce histamine release.<br />-high incidence of post op nausea and emesis .<br />
  16. 16. Absolute contraindication:<br /> -airway obstruction.<br /> -prophyria.<br /> -adrenal impairment.<br /> -long term infusion in ICU (increase infection <br /> and mortality).<br />
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  18. 18. Kitamine:<br />-Arylcyclohexylamine.<br />-water soluble compound.<br />-potent anesthetics and analgesic properties +amnesia .<br />-metabolized by liver to norkitamine which excreted by<br /> kidney.<br />-elimination half life 2-4 h .<br />-dose dependent CNS depression + stimulation of limbic s.<br />-induction dose: 1-2 mg/kg IV.<br /> 4-8mg/kg IM.<br />-duration of action: 10-20min –full orientation require<br /> more 60 – 90 min <br />
  19. 19. -high incidence of psychomimetic reactions (namely ,<br /> hallucination , nightmares , altered short term memory<br /> , and cognition).<br />-ketamine increase CPF and ICP .<br />-bronchodilatory activity - minimal respiratory depression.<br />-increase oral secretion.<br />-cardiovascular stimulation + increase peripheral resistant.<br />-not recommended in severe coronary artery disease.<br />-increase pulmonary artery pressure (contraindicated <br /> in poor right ventricular reserve.<br />
  20. 20. Indications:<br /> -high risk pt: shocked patients.<br /> -pediatric anesthesia.<br /> -difficult locations: site of accidents.<br /> -developing countries: where anesthetic<br /> equipment and trained staff in short supply.<br />
  21. 21. Benzodiazepines:<br />-medazolam , lorazepam , diazepam and antagonist <br /> flumazenil.<br />-metabolized in liver , excreted by kidney.<br />-short acting: midazolam - flumazenil.<br />-intermediate: diazepam.<br />-long acting: lorazepam.<br />-only midazolam can given by continuous infusion.<br />-all benzodiazepines produce: anxiolytic, anterograde<br /> amnesia, sedative, hypnotic, anticonvulsant, and<br /> spinally mediated muscle relaxant properties.<br />
  22. 22. -dose dependent respiratory depression.<br />-it depress the swallowing reflex and depress upper<br /> airway reflex activity.<br />-produce decrease in systemic vascular resistant and<br /> blood pressure in large doses.<br />-specific antagonist :flumazenil <br />
  23. 23. Dexmedetomidine:<br />-alpha 2 adreno receptor agonist.<br />-approved by FDA for the short term less than 24 h<br /> sedation of the mechanically ventilated pt in ICU.<br />-unique type of sedation-analgesia with less respiratory<br /> depression + amnestic affect .<br />-it produce hypotension and bradycardia more than<br /> diazepines.<br />-infusion rate 0.2-0.6 mcg/kg/h.<br />-improve post op pain control after major surgery.<br />-slower onset and offset than propofol , sedation <br /> like midazolam. -high cost.<br />
  24. 24. Thank you<br />

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