Computer generated transcript

Warning!
The following transcript was generated automatically from the content and has not been checked or corrected manually.

Medical Series: Anaesthetic Pharmacology Dr. Acute Medicineman Trust Grade Doctor With Dr. Alec Beaney (Anaesthetist)Social MediasAnaesthetic triad Anaesthetics Sedatives Vasopressors Anaesthetic Pharmacology Muscle Analgesia Relaxation Antiemetics Case 1 Question You’re an F1 who is attending the emergency theatre list with a consultant anaesthetist. A 22-year-old gentleman is being rushed in because of a ruptured rapid sequence induction and uses an agent which causes the patient tor a fasciculate. Which muscle paralysis agent was used? A. Rocuronium B. Atracurium C. Suxamethonium D. Vecuronium E. Don’t know Case 1 Answer Which muscle paralysis agent was All the other agents are non-depolarizing used? and do not cause fasciculations. The only A. Rocuronium other NDMR used in RSIs (rapid sequence B. Atracurium inductions) is Rocuronium which is C. Suxamethonium D. Vecuronium increasingly being used. E. Don’t know Suxamethonium (AKA Succinylcholine) Depolarising muscle relaxant used in rapid sequence induction Causes global fasciculations which tells when a patient is paralysed Structurally it is two acetylcholine molecules bound togetherSuxamethonium Acetylcholine O N + O Case 1 Suxamethonium • Suxamethonium = 2 x Acetylcholine molecules. • Non-competitive irreversible binding to NAChR (Nicotinic) • Depolarising = Muscle fasciculation • Metabolised by plasma cholinesterases. • Plasma cholinesterase deficiency = sux apnoea • Inherited = E1 gene mutation and autosomal dominant = hours • Acquired= minutes • S/E- Myalgia, hyperkalaemia, ICP/IOP increased, sux apnoea, malignant hyperthermia • C/I- spinal injury, multi-trauma, burns and sux apnoea Hx. Case 2 Question You’re an F1 who is attending the elective gynae theatre list with a consultant anaesthetist. A 54-year-old lady is undergoing an elective laparoscopic relaxant induction. Which muscle paralysis agent was used?l and a muscle A. Glycopyrrolate B. Atracurium C. Suxamethonium D. Ketamine E. Don’t know Case 2 Answer Which muscle paralysis agent was Glycopyrrolate – muscarinic anticholinergic used? used with neostigmine to prevent bradycardia. A. Glycopyrrolate B. Atracurium Suxamethonium is not used in elective surgery. C. Suxamethonium Ketamine used in an RSI in haemodynamically D. Ketamine unstable patients. E. Don’t know Atracurium Non-depolarizing muscle relaxant used in elective surgery and is reversible with neostigmine. Neuromuscular Junction Pre-synaptic Muscle Nicotinic AChR Organophosphates Neostigmine Atracurium AChE C. Tetani Toxin Atracurium C. Botulinium Toxin Suxamethonium Plasma ChE Case 2 Muscle Paralysis Agents Agent Mechanism Effect Reversal Use agent Suxamethonium Depolarising muscle Full muscle None RSI relaxant fasciculations Irreversible non- followed by competitive binding to paralysis. NAChR Atracurium/ Non-depolarizing Paralysis but no Neostigmine Elective anaesthesia other muscle relaxant. fasciculations as Reversible binding non-depolarising. Rocuronium Non-depolarizing Same as above. Neostigmine RSI muscle relaxant. Sugammadex Elective anaesthesia Reversible binding Case 3 Question You’re an F1 who is attending the elective gynae theatre list with a consultant anaesthetist. A 54-year-old lady is undergoing an elective 70/30 and heart rate is 70. The anaesthetist administers a medicationtion through a peripheral cannula. Which drug did they likely administer? A.Noradrenaline B.Metaraminol C.Ephedrine D.Atropine E.Don’t know 1 Case 3 Answer Which drug did they likely not first line and requires a central line.weak beta agonism), usually administer? A. Noradrenaline therefore useful in hypotensive bradycardic patients due toanaesthesia.ts, B. Metaraminol Can be given peripherally. Atropine. Muscarinic anticholinergic used in significant bradycardias with C. Ephedrine hypotension, but not used for low blood pressure alone. D. Atropine E. Don’t know Metaraminol Commonly used vasopressor during anaesthesia. Can cause reflex bradycardia, therefore careful in bradycardic patients. Can be given through peripheral line. Metaraminol can cause a reflex bradycardia. Must make sure heart rate is not too slow. CN III, VII, IX, X T1 α 1 Noradrenaline α 2 Metaraminol VMC L Ephedrine - T β 1 l β 2 + Other smooth muscles S β 3 Ephedrine inhibits noradrenalin reuptake. L2 Effects are weaker than orad. S2, 3 , 4 keeps you’re s*** off the floor 3P’s = Poo, pee and procreate.MAP = CO x SVR 1 β CO = SV xChronotropy PreloadtraAfterload (Filling)opening aortic valve) 1 Case 3 Vasopressors Agent Mechanism Effect Notes Metaraminol alpha-1 adrenergic agonist Arteriolar vasoconstriction Reflex bradycardia Ephedrine Alpha and beta adrenergic Arteriolar vasoconstriction. Given when hypotensive agonist Iono/chronotropy. and bradycardic during Also indirect alpha agonist Prevention of reuptake of anaesthesia. through norad noradrenaline. Noradrenaline More potent alpha agonist than Arteriolar vasoconstriction. Can only be given metaraminol and weak beta through central line. agonist. Case 4 Question You’re a 5th year medical student attending a placement in ICU. A 24-year-old patient is currently being intubated and ventilated following a hypoxic cardiac arrest due to a drug overdose. He currently has a propofol infusion running. How does propofol work? A. NMDA antagonism B. GABAa agonism C. Serotoneric antagonist D. Dopaminergic antagonist E. Don’t know Case 4 Answer How does propofol work? NMDA antagonism. Glutamate binds to these receptor A. NMDA antagonism Target of dementia drugs (memantine) and ketamine.GABA. B. GABAa agonism Serotoneric antagonist. Target often of antiemetics, C. Serotoneric antagonist some antipsychotic and anti-migraine medications. D. Dopaminergic antagonist Dopaminergic antagonist. Target of Parkinson’s, E. Don’t know antipsychotic and antiemetic medications. Propofol Main inhibitory neurotransmitter is GABA. Propofol increases activity ofGABAa receptors. This is the same receptorsbenzodiapines and barbiturates act on. Case 4 GABA Receptors Agent Mechanism Effect Notes Propofol Enhances effect of GABA Lower doses sedation Propofol infusion Anaesthesia syndrome Reduces SVR Benzodiazepine Enhances effect of GABA. Sedation Treatment in seizure, Increases frequency of open Anxiolytic organophosphate chloride channels. poisoning Barbiturate Enhances effect of GABA. Anaesthesia Can only be given Increases duration of chloridAntiepileptic medication through central line. channel opening. Case 5 Question undergoing a rigid cystoscopy and urethral biopsy under GA. He has a proseal LMA inserted withis sevofluorane as maintenance with a good MAC. During the procedure his heart rate increases shows no acute changes. The anaesthetist administers a medication and the signs resolve. WhichCG receptor does this drug act on? A. GABAa receptors B. μ-opioid receptors C. K-opioid receptors D. Muscarinic receptors E. Don’t know Case 5 Answer What receptor does it act on? seizures, patient is already unconscious with propofol.icated in A. GABAa receptors analgesic effects, but produces dysphoria and other side effects. Bound B. μ-opioid receptors to by other meds. C. K-opioid receptors Muscarinic receptors. Drugs such as atropine and would produce effects opposite the sympathetic nervous system, but that would be masking D. Muscarinic receptors the issue at hand! E. Don’t know Fentanyl Fentanyl (opioid) was likely administered because of pain due to surgery, which is why the patient was exhibiting signs of sympathetic activity. Case 5 Opiates Agent Mechanism Equivalency to oramorph IV conversion Codeine Prodrug to morphine. 10:1 N/A Variable metabolism. CYP2D6 Tramadol Also acts as a neuropathic ag10:1 1:1 CYP2D6 Morphine μ-opioid receptors 1:1 2:1 PCA μ-opioid receptors 1.5:1 2:1 Oxycodone 1.5x stronger orally PCA Safe with poor renal function Fentanyl (patch) μ-opioid receptors 100:1 Anesthetist/ICU only Safe with poor renal functionTotal daily oramorph mg/day to PCA Rapid onset mcg/hour ICD Case 6 Question You’re a 5th year medical student attending an elective gynae list. A 25-year-old lady is undergoing an elective exploratory laparoscopy for suspected endometriosis. After induction the anaesthetist administers ondansetron and dexamethasone. Which receptor does ondansetron work on? A. D2 B. 5-HT3 C. H1 D. B3 E. Don’t know Case 6 Answer What receptor does it act on? D2. Metoclopramide is a dopaminergic antagonist. D A. D2 is the second last letter in metoclopramide B. 5-HT3 H1. Cyclizine is a histamine antagonist. cyclizINE, C. H1 histamINE. D. B3 B3. Adrenergic receptor on fat cells, has no relation E. Don’t know anti-emetics. Ondansetron It is a serotonin receptor antagonist act on the vomitingcentre and GI in preventing sickness. Associated with prolonged QT and constipation. Sensory/Thought input M1 Vestibular Centre H1 H1 Vomiting Centre 5-HT3 Stretch receptors Toxins H1 Chemotherapy GI input Chemoreceptor Opiates Trigger Zone 5-HT3 Anaesthetics D2 Case 6 Antiemetics Agent Mechanism Effect Notes Ondansetron 5-HT3 receptor antagonist GI Can cause constipation Vomiting centre Prolonged QT Metoclopramide D2 receptor antagonist CTZ Also a prokinetic Extrapyramidal symptoms Avoid in bowel obstruction/perforation H1 antagonist Good for all causes of Transient tachycardia Cyclizine nausea/vomiting CTZ Gets peeps high Vomiting centre Vestibular centre 5-HT3 receptor antagonism but Synergistic effect with Dexamethasone not fully understood. ondansetron commonly used in combination to prevent PONV. Case 7 Question following an ileostomy formation due to caecal perforation. 7 days post-port operatively she becomes very delirious and believes the staff are trying to harm her. She is attempting to get out of bed and pull out her lines. You try to de-escalate but are unable to. What medication will you administer? A. Diazepam B. Lorazepam C. Olanzapine D. Propranolol E. Don’t know Case 7 Answer Diazepam. Longer half-life of days due to its metabolites and What receptor does it act on? not normally used for rapid tranquilisation. A. Diazepam Olanzapine. Blocks dopamine receptors can be used for rapid B. Lorazepam tranq but second line in the context of a non-psychotic C. Olanzapine patient. Propranolol. Beta-blocker can be used in anxious patients D. Propranolol with excessive adrenergic symptoms, but not appropriate for E. Don’t know the current situation. Lorazepam Shorter acting than diazepam and first line in NICE guidance. Case 7 Antiemetics Agent Mechanism Effect Notes Diazepam Benzodiazepine, enhances Lower doses sedation Propofol infusion effects of GABA Anaesthesia syndrome Reduces SVR Lorazepam Benzodiazepine, enhances Sedation Treatment in seizures, effects of GABA Anxiolytic organophosphate poisoning Atypical antipsychoticn, not Anxiolytic Olanzapine Acts on multiple receptors Reduce positive symptoms- such as through dopamine and 5-HT2 hallucinations. (Serotonin) receptor antagonism. Case 8 Question You’re an F1 following a patient to recovery. A 45-year-old lady is just post-operative for a. 7 days post-operatively for gynae surgery. She is complaining of pain despite a fentanyl injection and having had intravenous paracetamol. The anaesthetist administers intravenous Parocoxib. How does it work? A. M-opioids receptors B. COX-1 inhibition C. COX-2 inhibition D. Phospholipase A2 inhibition E. Don’t know Case 8 Answer How does it work? M-opioids receptors – binding site of opiates A. M-opioids receptors and endorphins. B. COX-1 inhibition COX-1 inhibition- Salicylates > NSAIDs, inhibits C. COX-2 inhibition primary haemostasis. D. Phospholipase A2 inhibition Phospholipase A2 inhibition– Inhibited by E. Don’t know steroids. Parocoxib A type of intravenous selective intravenous NSAID for COX-2 inhibition. Reduces inflammation and pain. Arachidonic Acid Pathway Phospholipids e.g. Montelukast Steroids Phospholipase A2 Leukotriene Inhibitors Arachidonic Acid Prostaglandin H2 Leukotrienes Bronchoconstriction Irreversible acetylation COX 1 > COX 2 COX-2 Salicylates COX-1 NSAIDs COX-2 inhibitor e.g. Parocoxib TXA Pg I2 Pg E2 Primary hemostasisDecreased platelet aggregation Pain Platelet aggregationGastric mucosal protection Inflammation Vasoconstriction Afferent glomerular arteriole dilation O O F Feedback & Instagram + 3C N O Please complete feedback to receive slides and cheat sheet!Follow our In3tagram pa e for MCQs! NH O Cl CH 3 CH3 OH CH 3 CH OH 3 3HC CH3 3HC O