Anesthetics and Local Anesthetics Flashcards
Anesthetic action is terminated how in general?
Redistribution from the site of anesthesia
General anesthetics terminate how?
Leave brain
Local anesthetics terminate how?
Leave site of action
8 associated anesthesia effects
Relieve anxiety Sedation Prevent allergic response Prevent aspiration of stomach contents or emesis Analgesia Prevent bradycardia Prevent pulmonary fluid secretions Facilitation of incubation and relaxation
Ideal anesthetic: Timing of analgesia Consciousness Skeletal muscle Reflexes Memory Safety
Analgesia that persists after procedure itself
Rapidly reversible depression of consciousness
Relaxation of skeletal muscle
Reduction in reflexes
Amnesia
Safety in operating room
Is any drug perfect?
No
What drug comes close to perfect?
What’s wrong?
Ether
Not safe for the operating room staff
Four stages of anesthesia?
Which is target?
Which do you want to pass quickly?
Which do you want to avoid
Analgesia
Disinhibition: Pass through quickly
Surgical anesthesia: Target
Medullary depression: Avoid
Disinhibition stage Mental status Reflex change Respiration change GI change
Delirium and excitation
Reflexes enhanced
Respiration irregular
Nausea and vomiting
Surgical anesthesia: Consciousness Reflexes Heart changes Temperature change Respiratory rate
Unconscious No pain reflexes Stable BP and rate Temp stable Normal respiratory rate
How to get respiratory rate lower in surgical anesthesia safely
Oxygen supplementation
2 severe aspects of medullary depression
Severe respiratory and CV depression
3 parts of surgical anesthesia?
Induction
Maintenance
Recovery
Goal of induction
Quick into anesthesia and to bypass disinhibition/excitatory phase
Goal of maintenance
Maintain surgical anesthesia and vital functions
Goal of recovery
Rapid emergence from anesthesia with short disinhibition
Recovery is complete when the patient is? 3
Conscious
Alert
Responsive
Two theories of how anesthetics work
Membrane expansion by 0.4% disrupts sodium channel function –> Decrease excitability
Anesthetic receptor that when activated interferes with sodium or chloride function.
Most likely common anesthetic receptor target?
GABA
Primary site of inhaled anesthetics
Brain/CNS
Minimum Alveolar Concentration is what type of measurement?
Define
Dosage
Level needed to get 1/2 patients anesthetized in order to do a surgical incision 3 inches long in abdomen through all layers of muscle
Rapid induction needs a MAC of what?
1.3/1.5
Why is nitrous oxide never used solo?
MAC > 100.0
Explain the relationship of solubility, induction and emergence and equilibrium.
Less soluble the gas –> Faster it reaches equilibrium –> Faster the induction and emergence
Effect of inspired concentration on equilibrium
Higher the concentration –> Faster the equilibrium
Deeper or faster inspiration effect on equilibrium?
Deeper or faster inspirations mean faster equilibrium
Cardiac output effect on equilibrium
Faster CO –> Faster delivery
What is the second gas effect?
Two gases put together actually gives a faster effect (increases concentration gradient)
Why do you want a scavenger with a anesthetic apparatus?
Want what the patient is breathing out to not go into the surrounding room.
What is an active scavenger?
Draws gas back out
What is a passive scavenger?
Anesthetic is trapped in a chemical trap as patient breathes
What happens when you turn off NO anesthetic?
NO rushes back into the alveolar space –> Displaces oxygen –> Diffusion hypoxia
How to offset diffusion hypoxia? (2)
100% O2 administration
Maintaining normal ventilation
Malignant hyperthermia is most common with what?
What is it related to?
Halogenated anesthetic or succinylcholine
Increased myoplasmic calcium levels and increased coupling –> Leaving calcium causes contractions to continue
How to treat malignant hyperthermia (3)
Withdraw drug
Cool patient
Treat with dantrolene
Halothane 2 uses Effect on CV Effect on Respiratory Effect on SNS Effect on myocardium 1 toxic side effect
Uses: Weak analgesic + muscle relaxant CV: Depress Resp: Depress SNS: Block SNS reflexes Myocardium: More sensitive to catecholamines (arrhythmia) Toxicity: Hepato
Enflurane Use: CV: SNS effect: Myocardium effect: Toxicity And why: Adverse effect Contraindication
Same as halothane CV depressant No SNS effect Sensitizes myocardium to catecholamines Renal Biotransformation product has fluoride Lowers seizure threshold Contraindicated in labor
Isoflurane and Desflurane
Respiratory effect
CV effect:
Myocardium effect
Resp: Stimulation of reflex and secretions
CV: None
Myocardium: None
Desflurane Advantage: Reacts with what To form what: Causes what: How to alleviate
Ad: Fast induction sand rapid adjustments Dry absorbents Carbon monoxide Carboxyhemoglobinemia Use appropriate scavenger
Nitrous Oxide MAC Use solo: Use overall: What effect to watch: Respiratory effect: CV effect
MAC: Over 100% Solo use: Do NOT Use overall: Analgesic Effect to watch: 2nd gas effect Resp: Potentiate depression of other drugs CV effect: Depressant
Sevoflurane
Who likes it the most:
Induction/Emergence speed
Adverse effect:
Kids like it the most –> Sweet scent
Fast induction and emergence
Adverse
