=====Anaesthesia=====
==== Local anaesthetic agents: ====
^  ^doses are for regional anaesthetic only  ^
|  |amide LA's - metabolised in liver\\   Ester LA's - metab by hydrolysis (plasma esterases)|
|**Lignocaine**|amide LA\\  duration:30-120mins\\  3-5mg/kg, max.200 mg  |
|**Bupivacaine**|amide LA\\  duration:120-240mins\\  Slower onset (up to 30mins for full effect) but longer duration of action than other local anaesthetics. \\  2mg/kg, to 150 mg, using a 2.5 mg/mL (0.25%) solution  |
|**Levobupivacaine**|amide LA\\  bupivacaine isomer with fewer adverse effects\\  Up to 150 mg, using a 2.5 mg/mL (0.25%) solution  |
|**Prilocaine**|amide LA\\  duration:30-120mins\\  least toxicity of the amides\\  3mg/kg using 0.5% solution\\  usually used for IV regional anaesthesia (Bier's block)\\  //**Methaemoglobinaemia**// is specific toxicity of prilocaine but at much higher doses  |
|**Ropivacaine**|amide-type derived from bupivacaine, less cardiotoxic but also less potent\\  3mg/kg, to 200 mg, using 2 mg/mL (0.2%) solution  |
|**Tetracaine**|para-aminobenzoic acid ester, effective LA for topical use  |
|  ^//**Toxicity of all**// - dose dependent CNS effects from tingling to seizures. Vasodilation and vasoconstriction at higher doses, -ve inotropy.\\  //**Hypersensitivity**// - rare but more so with Esters  |

====Sedation and Analgesia=====
^    ^Adult  ^Paediatric  |
^Midazolam   |• Binds to α/γ interface of the receptor, increasing affinity of the receptor for GABA (GABA<sub>A&B</sub>)\\  • Sedation/Amnesia\\  • may have slightly more muscle relaxant effect than propofol because if it's broader GABA rec activity\\ • side effects - reduced Tidal Vol, tachypnoea, respiratory depression (occ apnoea), hypotension.\\  • //**Dose:**// ≤2.5mg and titrate 1mg every few minutes to effect\\ • //**Half life**// ~ 1/24 |• May cause agitation in children\\ • //**Dose:**//≤2mg and titrate 1mg every few minutes to effect, max 10mg  |
^Propofol   |• Sedation/Amnesia\\  • potentiates GABA (GABA<sub>A</sub>) mediated inhibitory tone in the CNS by decreasing the rate of dissociation of GABA from the receptor\\  • side effects - hypotension, resp depression, pain with injection\\  • pre-oxygenation is //probably// appropriate, esp in children\\  • **was** considered unsafe in patients with egg, soy allergies - no longer\\  • //**propofol infusion syndrome**// - in setting of prolonged and high dose infusion, acute refractory brady progressing to asystole in setting of metabolic acidosis, rhabdomyolysis,hyperlipidemia, and liver disease\\  • //**Dose:**// 0.5-1mg/kg (≤20mg in elderly) & titrate 0.25-0.5mg/kg to effect\\  • //**Half life**// for initial dose - 40mins|• //**Dose:**// >2yr old - 0.5-2mg/kg then titrate 0.5mg/kg every minutes to effect, max 3mg/kg  |
^Ketamine   |• Sedation/Amnesia/Analgesia\\  • dose response is not linear and dissociation usually appears at a threshold which is then maintained with further doses\\  • side effects - tachycardia, hypertension, laryngospasm, unpleasant hallucinations (reduced by pre-medication with a benzodiazepine), nausea and vomiting\\  • Contraindications - schizophrenia, resp and CVS disease \\  • //**Dose:**// 1mg/kg (≤30mg in elderly) & titrate 0.25-0.5mg/kg every few minutes to effect  |• //**Dose:**// >3/12 only, 1.5-2mg/kg then 0.5-1mg/kg after 5-10mins |
^Nitrous Oxide  |• still some debate about mode of action\\ • analgesia - opioid in nature (possibly by inducing release of endogenous opioid peptides) and may involve a number of spinal neuromodulators.\\ • anxiolytic - similar to benzodiazepines (possibly by activating BZ binding) & may involve GABA receptors.\\ • anaesthesic - may involve GABA and possibly N-methyl-D-aspartate receptors.\\ •**//contraindications//** - patients with likely air-filled cavities, including pneumothorax, pulmonary blebs, air embolism, bowel obstruction, and those undergoing surgery of the middle ear. |  |
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==References include:==
[[https://www.bjanaesthesia.org.uk/article/S0007-0912(17)36341-9/fulltext|BJ anaesthesia article  ]] \\  
http://www.partone.lifeinthefastlane.com/local_anaesthetics.html \\  
https://www.scottishintensivecare.org.uk/uploads/2014-07-08-00-14-41-RSIbrochurepdf-76814.pdf\\  
[[https://www.rcem.ac.uk/docs/College%20Guidelines/Pharmacological%20Agents%20for%20Procedural%20Sedation%20and%20Analgesia%20(Oct%202016).pdf|UK EM college guidelines - sedation and analgesia]]\\  
[[http://www.dickyricky.com/Medicine/Papers/2018%20Ann%20Emerg%20Med%20Clinical%20Practice%20Guideline%20for%20Emergency%20Department%20Procedural%20Sedation%20With%20Propofol.pdf|ACEP propofol guidelines 2018 ]]\\  
https://www.openanesthesia.org/\\ 
[[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5703690/| Muscle relaxant comparison - propofol and Midazolam ]]\\ 
[[https://emedicine.medscape.com/article/1413427-overview#a3|Emed Nitrous]]\\ 
[[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1821130/|Advances in understanding N2O]]\\