T1 L21. Analgesics, Anaesthetic and Sedative Drugs (JC)(1).ppt

Analgesia Sedation Local Anaesthetics Dr Jim Cooper Anaesthetist October 2022 INTRODUCTION • • • • • Definitions History Choice of Drug Mechanism of action Side effects ANALGESIA "The old nun had told me that I was committing a terrible sin, that Almighty God in His inscrutable wisdom had wi...

Analgesia Sedation Local Anaesthetics Dr Jim Cooper Anaesthetist October 2022 INTRODUCTION • • • • • Definitions History Choice of Drug Mechanism of action Side effects ANALGESIA "The old nun had told me that I was committing a terrible sin, that Almighty God in His inscrutable wisdom had willed it so, that the more suffering He inflicted at the hour of death the more forgiving would He be on the Day of Judgement. Even sweet Soeur Philomene had looked at me disapprovingly when, alone among my comrades, I had come with my morphia syringe after the old padre had left the bed with his Last Sacrament". John 16/21 • All the pain and anguish shall be immediately forgotten on the birth of the child PAIN • “An unpleasant sensory and emotional experience associate with actual or potential tissue damage” • “What ever the patient says it is” Gate Theory • • • • Melzack and Wall C fibres lets pain through Ab Fibres stimulate inhibitory neurones Descending Pathways prevent central passage PAIN MODIFICATION • Nociceptor C, A delta fibres • Central Interpretation • Not just Drugs! Syria • No analgesics • No Anaesthetics • Most Hospitals shut PAIN SCORE • Linear • Smiley/Sad Faces • Mild Moderate Severe Excrutiating Ladder • NSAIDS/Paracetamol • Weak Opiates/ Local Anaesthetics • Strong Opiates PAIN LADDER 1 PAIN LADDER 2 OPIOIDS • • • • • Act on opioid Receptor and antagonised by Naloxone Naturally occurring eg Morphine ,Codeine Semi Synthetic eg Diamorphine Synthetic eg Fentanyl Weaker eg Codeine Methods of administration • • • • • Intravenous pca/infusion Intramuscular Oral Intra nasal/aerosol Epidural/spinal Where are Receptors • • • • • • Pons and Mid brain Periaqueductal Grey Matter Nucleus Raphe Magnus Spinal Cord Posterior Horn 1 and 2 GIT Peripheral Tissues Sub Types • MU 1 and 2 OP3 • Delta OP1 • Kappa OP2 Morphine • • • • • • Effects Side Effects Respiratory Depression/Airway Loss Nausea and Vomiting Constipation/Pruritis Miosis NALOXONE • ABC • Antidote with Caution KETAMINE • • • • • • • • NMDA Receptors Kappa and delta receptors Not GABA Analgesic local/general Anaesthetic Sedative SIDE EFFECTS emergence phenomena Sympathomimetic NSAIDS • • • • • • • Act by inhibiting Cyclooxygenase 1and 2 Analgesic, Antipyretic, Anti inflammatory Side Effects Gastric Irritation Bronchospasm Renal Impairment Platelet function ASPIRIN ASPIRIN • • • • Acetylsalycilic acid Oxidative phosphorylation Air Hunger Reyes Syndrome Paracetamol • • • • Mechanism of Action ? Central prostaglandin effect/unknown Side effects OVERDOSE Hepatotoxicity/glutathione depletion N acetylcysteine Other Analgesia • • • • • • • Anxiolysis Local anaesthetics Antidepressants,antiepileptics Guanethadine, gabapentin, clonidine Acupuncture Inhalational Nitrous oxide/penthrane Tramadol Ether ANTI EMETICS • • • • • • • • • • Avoidance Cyclizine Ondansetron 5ht3 antagonist hyoscine Metaclopromide Steroids Prochlorperazine Cannabinoids Propofol People remember! SEDATION Ramsay Sedation Scale • • • • • • Patient Anxious Cooperative Responds only to commands Brisk response to Glabellar Tap/Shout Sluggish Response No response Benzodiazapines • • • • • • Midazolam, Diazepam, Lorazepam Routes of administration PHYSIOLOGY Gabba- aminobutyric Acid Inhibitory Neurotransmittor Receptors A and B Side Effect • • • • • • Over Sedation Loss of Airway Respiratory Depression ABC Flumazanyl with caution Myth of safety ,Light Anaesthesia Other Sedatives • • • • • • Low Dose Vapours Ketamine Hyoscine 1944 Propofol Low dose Remifentanyl/alfentanyl Major Tranquillisers LOCAL ANAESTHETICS HISTORY • Cocaine • Bier 1908 • Freud Classification • • • • Amides -NH.COLignocaine,Prilocaine,Bupivacaine Esters –CO.OCocaine , Amethocaine Mechanism of Action • • • • Na Channel Blockade Un- ionized Drug Through Membrane into axoplasm Protonated Blocks Channel thus blocking action potential Where to put them (house of God) • • • • • • Fun Part! Anatomy Local Blocks /Ultrasound Spinal Epidural Caudal Skin Aerosol/Nebulised Combination with GA Part of Triad SIDE EFFECTS • • • • • • Skin/Subcutaneous Brachial Plexus Epidural Caudal Intercostal VESSELS AND NERVES FOLLOW EACH OTHER TOXICITY • • • • • • CARDIOVASCULAR Dysrythmias,Cardiac Depression CENTRAL NERVOUS SYSTEM Fitting/Anxiety/Lossof Consciousness Circumoral numbness Ref Paper Mask 1990 Treatment • • • • ABC Oxygen Lipid 20% Dysrythmias/fitting SUMMARY • • • • ANALGESIA/ ANTIEMETICS SEDATION LOCAL ANAESTHETICS Patient Comfort , Dignity, Treatment QUESTIONS?