Anaesthesia Dr Rob Stephens Physiological and Pharmacological principles Dr Andy Badacsonyi Anaesthesia in the 21st century BREAK Dr Brigitta Brandner Acute Pain Management Dr Rob Stephens Physiological and Pharmacological principles Dr Andy Badacsonyi Anaesthesia in the 21st century BREAK Dr Brigitta Brandner Acute Pain Management

Dr Rob Stephens Thanks to Drs James Holding and Maryam Jadidi Dr Rob Stephens Thanks to Drs James Holding and Maryam Jadidi Physiology and …

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

Introduction General word: website, documents, coming to theatre General word: website, documents, coming to theatre

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

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

CVS physiology MAP = CO x SVR HR x SV Vaso-? constricted ? dilated

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

Anaesthesia and CVS

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

Cardiovascular changes ‘artists impression’ version often filled in!

Induction of anaesthesia Preopera tive

Surgical stimulation Incision

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

Respiratory Upper – Airway Lower- Trachea, lungs, muscles Upper – Airway Lower- Trachea, lungs, muscles

Respiratory- Airway Anaesthesia ‘Obtunds’ airway =“Airway obstruction’ = no airflow = no 0 2 = Badness Anaesthesia ‘Obtunds’ airway =“Airway obstruction’ = no airflow = no 0 2 = Badness

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

Guedel / Oro-Pharyngeal Adult male Adult female Guedel size 4 size 3

Laryngeal Mask Airway

Respiratory- Airway

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

CT scan of Diaphragm during awake spontaneous breathing

CT scan of Diaphragm during anaesthesia: Atelectasis

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)

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

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

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!

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

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

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

Hypnosis: Propofol

Hypnosis: Propofol (and others) IV Redistributed out of CNS metabolised CVS - CO x SVR = MAP RS airway and lungs NS pain on injection

Maintenance: Volatiles Air Oxygen Sevoflurane

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

MAC = minimum alveolar concentration

Muscle Paralysis

Neuromuscular blockers Depolarising Suxamethonium Non-depolarising Atracurium Vecuronium Rocuronium Depolarising Suxamethonium Non-depolarising Atracurium Vecuronium Rocuronium

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

Nicotinic ACh Receptor

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

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

Uppers Anticholinergics Atropine Glycopyrulate μg Symatheto-mimetics  1 agonists Phenylepherine Metaraminol mg Ephedrine mixed  and  adreno agonist Anticholinergics Atropine Glycopyrulate μg Symatheto-mimetics  1 agonists Phenylepherine Metaraminol mg Ephedrine mixed  and  adreno agonist MAP = CO x SVR  1  2 11

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

Antiemetics

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

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

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