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Anaesthesia 13.30 - 14.30Dr Rob Stephens Physiological and Pharmacological principles 14.30 - 15.30Dr Andy Badacsonyi Anaesthesia in the 21st century 15.30 - 15.45 BREAK 15.45 - 16.45 Dr Brigitta Brandner Acute Pain Management 13.30 - 14.30Dr Rob Stephens Physiological and Pharmacological principles 14.30 - 15.30Dr Andy Badacsonyi Anaesthesia in the 21st century 15.30 - 15.45 BREAK 15.45 - 16.45 Dr Brigitta Brandner Acute Pain Management
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Dr Rob Stephens Thanks to Drs James Holding and Maryam Jadidi Dr Rob Stephens Thanks to Drs James Holding and Maryam Jadidi Physiology and …
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Contents Introduction Physiology CVS, RS, NS, Other Pharmacolgy Anaesthetic/ Hypnotic Agents Neuromuscular Paralysis & Reversal Analgesia Others, CVS, Gasses, Fluids Introduction Physiology CVS, RS, NS, Other Pharmacolgy Anaesthetic/ Hypnotic Agents Neuromuscular Paralysis & Reversal Analgesia Others, CVS, Gasses, Fluids
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Introduction General word: website, documents, coming to theatre General word: website, documents, coming to theatre
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Introduction Anaesthesia is more than Physiology and Pharmacology! Surgery vs Anaesthesia Outside theatre Anaesthesia is more than Physiology and Pharmacology! Surgery vs Anaesthesia Outside theatre
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CVS physiology O 2 + C 6 H 12 O 6 CO 2 + H 2 O ATP O 2 delivery =Amount of O 2 to tissues per minute =Cardiac Output x O 2 content of blood x HR x SV Hb x Sa0 2 x constant
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CVS physiology MAP = CO x SVR HR x SV Vaso-? constricted ? dilated
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CVS physiology: Heart Heart pumps blood (0 2 ) from lungs to tissues then back to heart / lungs (C0 2 ) Work =0 2 needs rate pre / afterload contractility Heart pumps blood (0 2 ) from lungs to tissues then back to heart / lungs (C0 2 ) Work =0 2 needs rate pre / afterload contractility
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Anaesthesia and CVS
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CVS effects.. Anxiety, illness, walking to theatre, pain Induction of general anaesthesia or onset of epidural/ spinal anaesthesia Cardiovascular - active drugs Intubation Surgical stimulation / trauma Haemorrhage Extubation ?Recovery or complication Anxiety, illness, walking to theatre, pain Induction of general anaesthesia or onset of epidural/ spinal anaesthesia Cardiovascular - active drugs Intubation Surgical stimulation / trauma Haemorrhage Extubation ?Recovery or complication
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Cardiovascular changes ‘artists impression’ version often filled in!
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Induction of anaesthesia Preopera tive
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Surgical stimulation Incision
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Cardiovascular Bleeding Less oxygen in blood Less pressure at Atrial and Aortic stretch Sympathetic ++ response (+renal, adrenal) Blood pressure maintained … Less oxygen in blood Less pressure at Atrial and Aortic stretch Sympathetic ++ response (+renal, adrenal) Blood pressure maintained … CO x SVR ↑HR x ↑SV vasocontricts ↑ ↑ +ve inotrope +ve chronotrope vasocontricts
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Respiratory Upper – Airway Lower- Trachea, lungs, muscles Upper – Airway Lower- Trachea, lungs, muscles
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Respiratory- Airway Anaesthesia ‘Obtunds’ airway =“Airway obstruction’ = no airflow = no 0 2 = Badness Anaesthesia ‘Obtunds’ airway =“Airway obstruction’ = no airflow = no 0 2 = Badness
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Keep Airway open: Airway manoeuvres (chin lift etc) Airway devices- above vs blow cords Above Vocal Cords eg, gudel, LMA Below Vocal Cords - Into trachea = intubation, paralysis Keep Airway open: Airway manoeuvres (chin lift etc) Airway devices- above vs blow cords Above Vocal Cords eg, gudel, LMA Below Vocal Cords - Into trachea = intubation, paralysis Respiratory- Airway
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Guedel / Oro-Pharyngeal Adult male Adult female Guedel size 4 size 3
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Laryngeal Mask Airway
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Respiratory- Airway
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Respiratory- Lower/ Lungs Spontaneous vs Ventilated Lungs smaller depth Drugs respiratory rate Small airways / Alveolar collapse Can’t cough – secretions = ‘pulmonary shunt (vs deadspace) Hypoxaemia, persists postoperatively Spontaneous vs Ventilated Lungs smaller depth Drugs respiratory rate Small airways / Alveolar collapse Can’t cough – secretions = ‘pulmonary shunt (vs deadspace) Hypoxaemia, persists postoperatively
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CT scan of Diaphragm during awake spontaneous breathing
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CT scan of Diaphragm during anaesthesia: Atelectasis
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Gastrointestinal General Anaesthesia relaxes gastro-oesophageal sphincter Fluid up oesophagus ?into lungs starvation postoperative vomiting Other drugs (eg analgesia) General Anaesthesia relaxes gastro-oesophageal sphincter Fluid up oesophagus ?into lungs starvation postoperative vomiting Other drugs (eg analgesia)
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Neurology Many Effects GA drug induced reversable unconsciousness Many reflexes (airway, gag, CN) Awareness +/- NMJ paralysis Many Effects GA drug induced reversable unconsciousness Many reflexes (airway, gag, CN) Awareness +/- NMJ paralysis
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Physiology 2(3) factors determining blood pressure How does GA affect these? 3 words about GA on resp system 2(3) factors determining blood pressure How does GA affect these? 3 words about GA on resp system
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Contents Introduction – the classical triad Introduction – general principles Hypnotic Agents Neuromuscular Paralysis + Reversal Analgesia Cardiovascular Drugs – up and down Fluids and Gasses are drugs too!
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Pharmacology Introduction Anaesthesia ‘classical triad’ Hypnotic agent- unconsciousness Gas or IV Analgesia Neuromuscular Paralysis Induction, Maintenance, Emergence, Recovery Basics of anaesthesia: diagrams, handout & lecturehandout & lecture Anaesthesia ‘classical triad’ Hypnotic agent- unconsciousness Gas or IV Analgesia Neuromuscular Paralysis Induction, Maintenance, Emergence, Recovery Basics of anaesthesia: diagrams, handout & lecturehandout & lecture
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Introduction - Principles Pharmacokinetics What the body does to the drug Absorption, distribution, metabolism, elimination Pharmacodynamics What the drug does to the body – ie it’s effects CVS, RS, GI, NS, Other, Side effects Pharmacokinetics What the body does to the drug Absorption, distribution, metabolism, elimination Pharmacodynamics What the drug does to the body – ie it’s effects CVS, RS, GI, NS, Other, Side effects
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Typical Anaesthesia Intravenous induction Propofol Short acting opiate - e.g. fentanyl Hypnotic ‘anaesthetic’ - e.g. propofol Set up of anaesthetic maintenance - e.g. sevoflurane vapour in oxygen and air Specific muscle paralysis may be needed Definitive analgesia Anti-emetic Others Intravenous induction Propofol Short acting opiate - e.g. fentanyl Hypnotic ‘anaesthetic’ - e.g. propofol Set up of anaesthetic maintenance - e.g. sevoflurane vapour in oxygen and air Specific muscle paralysis may be needed Definitive analgesia Anti-emetic Others
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Hypnosis: Propofol
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Hypnosis: Propofol (and others) IV Redistributed out of CNS metabolised CVS - CO x SVR = MAP RS airway and lungs NS pain on injection
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Maintenance: Volatiles Air Oxygen Sevoflurane
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Maintenance Sevoflurane (‘SEVO’) Used for gaseous induction. Desflurane Isoflurane Gases, inhaled, little metabolised, exhaled CVS: CO x SVR = MAP RS- irritant, bronchodilate NS Given with Oxygen /Air /Nitrous Oxide Sevoflurane (‘SEVO’) Used for gaseous induction. Desflurane Isoflurane Gases, inhaled, little metabolised, exhaled CVS: CO x SVR = MAP RS- irritant, bronchodilate NS Given with Oxygen /Air /Nitrous Oxide CO x SVR = MAP
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MAC = minimum alveolar concentration
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Muscle Paralysis
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Neuromuscular blockers Depolarising Suxamethonium Non-depolarising Atracurium Vecuronium Rocuronium Depolarising Suxamethonium Non-depolarising Atracurium Vecuronium Rocuronium
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Neuromuscular blockers Depolarising Suxamethonium 2x Ach molecules Activates receptor Non-depolarising – competitive vs ACh Atracurium Vecuronium Rocuronium Depolarising Suxamethonium 2x Ach molecules Activates receptor Non-depolarising – competitive vs ACh Atracurium Vecuronium Rocuronium
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Nicotinic ACh Receptor
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Reversal of Paralysis Neostigmine Blocks cholinesterase Stimulates nicotinic and muscarinic Given with an anticholinergic Sugammadex Neostigmine Blocks cholinesterase Stimulates nicotinic and muscarinic Given with an anticholinergic Sugammadex
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Analgesia – Dr B Systemic Simple- paracetamol 1g NSAID – Diclofenac etc Opioids eg morphine 2mg bolus Others – Ketamine Regional – spinal / epidural / blocks Local - infiltration Systemic Simple- paracetamol 1g NSAID – Diclofenac etc Opioids eg morphine 2mg bolus Others – Ketamine Regional – spinal / epidural / blocks Local - infiltration
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Uppers Anticholinergics Atropine Glycopyrulate 200-600μg Symatheto-mimetics 1 agonists Phenylepherine Metaraminol 0.25-0.5 mg Ephedrine mixed and adreno agonist Anticholinergics Atropine Glycopyrulate 200-600μg Symatheto-mimetics 1 agonists Phenylepherine Metaraminol 0.25-0.5 mg Ephedrine mixed and adreno agonist MAP = CO x SVR 1 2 11
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Downers More anaesthetic or opiate / analgesia Short acting -blockers (labetalol, esmolol) Short acting blockers GTN Clonidine - 2 agonist clonidine More anaesthetic or opiate / analgesia Short acting -blockers (labetalol, esmolol) Short acting blockers GTN Clonidine - 2 agonist clonidine MAP = CO x SVR
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Antiemetics
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General- Hydrate, anxiety, gastric decompress Cyclizine anti-histamine S/E – tachycardia and other anti-cholinergic effects Ondansatron5-HT 3 receptor antagonists S/E – constipation + long QT Prochlorperazine (‘Stematil’) – DA and mACh receptor antagonist S/E – extrapyramidal Dexamethasone glucocorticoid S/E – deranged glucose control General- Hydrate, anxiety, gastric decompress Cyclizine anti-histamine S/E – tachycardia and other anti-cholinergic effects Ondansatron5-HT 3 receptor antagonists S/E – constipation + long QT Prochlorperazine (‘Stematil’) – DA and mACh receptor antagonist S/E – extrapyramidal Dexamethasone glucocorticoid S/E – deranged glucose control
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Fluids and Gasses are drugs too! Oxygen is a ‘drug’ Intravenous fluids Colloids Crystalloids Blood and products Articles on website / youtube Oxygen is a ‘drug’ Intravenous fluids Colloids Crystalloids Blood and products Articles on website / youtube
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General Advice Can always give more – can’t take away Caution in Unwell Elderly Hypovolaemic Lots of ways to anaesthetise- don’t worry Can always give more – can’t take away Caution in Unwell Elderly Hypovolaemic Lots of ways to anaesthetise- don’t worry
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