Week 6 Flashcards
(135 cards)
General anesthesia (balance)
balance btw hypnosis, analgesia (autonomic, somatic), and areflexia.
Modern inhaled anesthetics
Fluorinated ether derivatives
clinically relevant differences between inhaled anesthetics
potency, solubility, pungency, cost
distribution, elimination of inhaled anesthetics
uptake into blood and distributed 1) VRG (brain, liver, kidney) 2) fat 3) muscle. eliminated by ventilation (almost no metabolic breakdown)
solubility of inhaled anesthetics
low blood solubility = less potent, faster onset/offset, less accumulation in tissue/fat
MAC inhaled anesthetics
minimum alveolar concentration at which 50% patients will not move in response to surgical incision (hypnosis more important now)
MOA inhaled anesthetics
promiscuous binders allosterically and competitively. GABA-A.
Respiratory effects inhaled anesthetics
bronchodilation, inc rate, dec tidal volume, dec reflexes to maintain oxygenation/ventilation
CV effects inhaled anesthetics
Decrease blood pressure, redistribute blood from core to periphery. Impair autonomic reflexes, impaired contractile strength of heart.
pharmacokinetics of IV anesthetics
Redistribution terminates drug effect–not elimination! order of peaks: Plasma–>VRG–>muscle–>fat
Context-sensitive half time
longer you infuse a drug, the longer it takes to eliminate. Very fat-soluble drugs never get to steady state.
Propofol (mechanism, onset, use, metabolism, contraindications)
potentiates GABA (no effect on pain!), fast onset/offset, used for induction, TIVA, ICU sedation, partially metabolized in extrahepatic tissues. Redistribution > elimination! Egg allergy.
Etomidate (use, MOA, adverse effects)
induction drug of choice for hemodynamically compromised patients, potentiates GABA, causes adrenocortical suppression = reduced ability to compensate for shock!
Thiopental (general properties, contraindications)
similar to propofol, contraindicated in porhpyria
CV effects of IV anesthetics
hypotension!
Ketamine (autonomic effects, anesthetic advantages, disadvantages)
sympathetic stimulation, potent analgesic, causes dissociative anesthesia and dysphoria, no IV access required.
MOA local anesthetics
Cross membrane, bind intracellularly to Na+ channels in open and inactivated states. Acid reduces ability to cross membrane
amide local anesthetics
two “i”s in generic name. metabolized in hepatocytes, greater toxicity
ester local anesthetics
one “i” in generic name, metabolized in plasma to PABA (potential allergen), less toxic, OTC meds are esters.
pharmacology local anesthetics (solubility, pKa)
greater lipid solubility –> more potent, longer duration. Lower pKa–> more un-ionized–> more rapid onset.
toxicity and Tx of local anesthetics
tongue numbness, lightheadedness –> visual disturbance –> muscle twitching –> unconsciousness –> convulsion –> coma –> respiratory arrest. Ventricular arrhythmias. Intralipids given to absorb LA. Hyperventilate to generate acidosis
S vs R isomer local anesthetics
S preferred – reduced cardiotoxicity
Multi-Axial biopsychosocial model
I: clinical disorder (pervasive across all social interaction)
II: personality disorders, mental retardation, maladaptive personality features, defense mechanisms
III: general medical conditions
IV: psychosocial and environmental problems
V: global assessment of functioning
Organizational vs activational effects of gonadal hormones (and examples)
organizational = development, fetal exposure, considered permanent (eg high CAH in girls leads to "masculinization"). Activational = re-exposure later in development, transient and super-imposed on organizational effects