Good Drugs, Bad Drugs & Anesthesia PDF

Good Drugs, Bad Drugs & Anesthesia Part II Dr Tonia Timperley Tauh MD FRCPC PRESENTATION [email protected] [email protected] COVER OPTION 1 Lorem ipsum dolor sit amet, consectetur adipiscing elit.  LAST LECTURE GOOD DRUGS BAD DRUGS PART I...

Good Drugs, Bad Drugs & Anesthesia Part II Dr Tonia Timperley Tauh MD FRCPC PRESENTATION [email protected] [email protected] COVER OPTION 1 Lorem ipsum dolor sit amet, consectetur adipiscing elit.  LAST LECTURE GOOD DRUGS BAD DRUGS PART I Pain Non-opiate analgesia NSAIDs Acetaminophen Methocarbamol Opiates analgesia  DRUG: FENTANYL/MORPHINE 1. Class – Opiates 2. MOA – Calcium channel blocker 3. Use – Analgesia, additive anesthesia, sedation 4. Side Effects – … https://www2.gov.bc.ca/assets/gov/overdose-awareness/final_responding_to_bcs_opioid_overdose_epidemic_-  Higher opioid dose 3 or more prescribers 4 or more dispensing pharmacies Prescription of fentanyl Current substance use Mental health diagnosis (depression, bipolar disorder) Pancreatitis  C ASE 2 A 35 year old female is 4 days post surgery for motor vehicle accident injury? The surgeon prescribed him Hydromorphone (Dilaudid) While he takes acetaminophen, naproxen and hydromorphone, his brother teases him and says, “Why do you take so many it’s not good to mix drugs!” Is this true?  OPIATE ANTAGONIST Naloxone (Narcan) Reverse depressed respiration from opioid overdose Precipitate withdrawal symptoms Prevent dependent individuals from experiencing a high from subsequent opioid use Harm reduction strategy --> Several cities across north America have started providing naloxone to heroin users → fewer deaths.  DRUG: NALOXONE 1. Class – Opiate Antagonist 2. MOA – Binds onto the opiate mu receptor with high affinity and rapidly removes any molecules occupying the mu receptor 3. Use – Reverses respiratory depression, treats opioid induce pruritis 4. Side Effects – Reverses analgesia  OBJEC TIVES Local anesthetic Regional anesthesia Sedation anesthetic (Conscious Sedation) General anesthetic  GOOD DRUGS OR B AD DRUGS? All good drugs have bad ways to use them All bad drugs have good ways to use them Use the information you have around you to risk stratify – it’s readily available and free! The use of local anesthetic to block a large area in the body, such as an arm or a leg without needing to use general anesthesia. As part of surgical anesthesia For post operative pain and/or labour analgesia REGIONAL ANESTHESIA Local anesthetic Lidocaine Na+ channel blocker and prevents the propagation of nerve action  LOC AL ANESTHETIC Cocaine Lidocaine Prilocaine Bupivacaine REGIONAL ANESTHESIA – EPIDURAL VS SPINAL  REGIONAL ANESTHESIA - EPIDURAL A form of regional anesthesia that involves the injection of local anesthetic and /or opiates into the epidural space Used for continuous analgesia for labour pain, or post operative pain after abdomen or chest surgery Regional Anesthesia Spinal Epidural Peripheral Nerve blocks TAP block Digit ring block  REGIONAL ANESTHESIA - EPIDURAL Why epidural? Pain control intra and post operative care Use less general anesthetic An infusion and /or patient controlled analgesia Use less opiates systemically therefore less side effects like constipation, sedation and respiratory depression  QU ESTION A 46 year old female visits her dentist for a tooth extraction. The dentist administers lidocaine. What is the mechanism of action of lidocaine? What are some signs and symptoms of local anesthetic toxicity (too much lidocaine and in the wrong place?  DRUG: LIDOC AINE/COC AINE 1. Class – Local Anesthetic 2. MOA – Na+ channel blocker 3. Use – local or regional anesthetic for dental procedures, surgery, labour and pain management 4. Side Effects – Seizures and arrythmia and complete heart block A 34 year old gorilla getting a health check up  COMMON QUESTIONS BEFORE ANESTHESIA Am I going to die from anesthesia? How much pain am I going to have? Will I wake up during my surgery? Will I share my deepest and darkest secrets? What if I am allergic to the antibiotics/drugs/anesthesia? Do I have to stop drinking and eating before anesthesia? I would like to be completely knocked out for my surgery please?  General Light Sedation Deep Sedation Anesthesia Normal response to Purposeful response Responsiveness verbal commands to pain No response to pain Mildly collapsed but Breathing device Airway Unaffected no intervention required to keep required open Slow and deep Inadequate requiring Respiration & Spontaneous breath. assisted or Ventilation breathing Supplemental oxygen mechanical required ventilation Bradycardia Impaired requiring Cardiovascular Hypotension Normal pharmacological Function Body able to support compensate  SEDATION Oral medication IV medication  BENZODIAZEPINES Mechanism of Action: Benzodiazepine-receptor binding enhances the inhibitory effects of various neurotransmitters( ie GABA) Oral: Ativan (lorazepam), oxazepam IV: Midazolam SE: respiratory depression at high doses WHE N YO U GO TO YO UR D EN TIST, EN D OS CO P E, C OLO N O SCO P Y, C OLP O SC OP Y, BRO NC HOS CO P Y … AN Y ….SC O PIE S  With Propofol PROPOFOL Mechanism of action Without propofol Facilitation of inhibitory neurotransmission mediated by GABA Rapid onset Pleasant feeling, nice dreams. SE: Burns on injection, hypotension, bradycardia  GENERAL ANES THES IA Induction Maintenance Emergence  PHARMACOLOGY OF GENERAL ANESTHESIA Goals of anesthesia: amnesia, analgesia and anesthesia Anesthesia is achieved through upregulating inhibitory pathways and downregulating excitatory pathways Excitatory neurotransmitters– Acetylcholine (nicotinic), NMDA (N- Methyl-D-aspartate), and glutamate Inhibitory neurotransmitters – GABA, glycine Most important is GABA chloride channels PH ARMACO L OG Y Stole another slide from Dr Shabitt’s lecture… INDUCTION  PLASMA CONCENTRATION DOSE Alpha phase: redistribution from central compartments to peripheral tissues Beta phase: drug metabolism (plasma and liver enzymes) and excretion  MAINTENANCE ANESTHESIA (IE: TO KEEP YOU ASLEEP) Volatile Gas anesthetic IV anesthetic (delivered through your breathing tube into (delivered through your IV) your lungs) Plus titratable doses of opiates +/- Plus titratable doses of opiates +/- neuromuscular blockers neuromuscular blocker  MAINTENANCE & EMERGENCE IV Anesthetic Volatile Anesthetic Context sensitive half-time = the time taken for blood plasma concentration of a drug to decline by one half after an infusion has been stopped  IV AGENTS Propofol Ketamine Benzodiazepines: Diazepam, Midazolam Opiods: Fentanyl, Sufentanil, Morphine, Hydromorphone, Remifentanil Etomidate Barbituates: thiopental **  KETAMINE Mechanism of Action NMDA antagonist → increases catecholamines and serotonin Inhibits excitatory neurotransmitter effects in brain Acts as a dissociative anesthetic by dissociating the thalamus from the limbic cortex Less effect on respiration SE: tachycardia, hypertension, dissociative effects  RISKS OF DYING UNDER ANESTHESIA Consider Facts > Anxiety 1940’s 1:1000 1970’s 1:10 000 1990’s 1:100 000 2010’s 1: 1.1 million per year Surgical techniques (open vs laparoscopic) Anesthetic techniques (drugs, regional and sedation, monitoring) Kenya – surgeon administered anesthetics Preoperative assessment and optimization 1987 - Saturation probe Present day Cardiac Surgery Anesthesia  ANESTHESIA RELATED MORTALITY Epidemiology of Anesthesia-related Mortality in the United States, 1999–2005 The estimated rates from anesthesia-related deaths were 1.1 per million population per year (1.45 for males and 0.77 for females) and 8.2 per million hospital surgical discharges (11.7 for men and 6.5 for women). The highest death rates were found in persons aged 85 years and older. Transport Canada – Fatal Collision The number of fatalities per 100,000 population was 5.0 in 2017; the lowest on record.  Questions? Dr Tonia Timperley Tauh MD FRCPC PRESENTATION [email protected] [email protected] COVER OPTION 1 Lorem ipsum dolor sit amet, consectetur adipiscing elit.