Anesthetics Flashcards
Rapid induction & recovery due to low blood solubility (BGC 0.47, MAC >100%) The most potent analgesic Weak anesthetic (low potency, used combined others) No muscle relaxation No hepatotoxicity No respiratory depression Minimal CVS adverse effects. Adverse Effects Diffusion hypoxia Nausea and vomiting Deficiency of vitamin B12 Used in Outpatient anesthesia (dental practice) Obstetric analgesic (delivery)
N2O
Less potent than halothane Rapid and smooth induction and recovery. Better smell (non irritant) No airway irritation (children) CVS : Hypotension, little effect on HR No hepatotoxicity. No sensitization of the heart. No cardiac arrhythmias. develops hyperthermia.
Sevoflurane
Rapid induction & fast recovery than halothane (low blood solubility). Less potent than halothane. No hepatotoxicity. No sensitization of the heart. No cardiac arrhythmias. CARDIOVASCULAR DEPRESSION Pungent ODOR (airway irritation - cough) develops hyperthermia.
Desflurane
Less potent than halothane
Better analgesic action.
Faster induction & recovery than halothane
No hepatotoxicity.
SENSITIZATION OF HEART TO CATECHOLAMINES can contribute to ARRYTHMIAS.
CVS depression
Disadvantages pungent odor, slightly irritant (not for pediatrics or induction)
develops hyperthermia.
Isoflurane
Major route of removal of inhalant anesthetics
Lung
Enhance the activation of GABA receptors
Slower onset of action than thiopental
Not able to provide complete anesthesia
High incidence of anterograde amnesia - you won’t remember what happened during surgery, but you will remember your name after surgery - don’t encode new information but stored information not affected
Minimal depression of respiration or cardiovascular function-although may cause transient apnea if injected quickly
Benzodiazepines
Enhance the activation of GABA receptors
Rapid onset of sedation
Rapid recovery after bolus dose due to redistribution
Slower recovery after infusion (same reason)
Transient decrease in blood pressure offset by compensatory elevation in heart rate
Depression of respiration
Clinical uses:
Primary use as an induction agent
Anesthesia may be adequate for short procedures
Can be used to decrease intracranial pressure
Decrease perfusion but also decrease oxygen requirements of CNS
Thiopental, Methohexital
more water soluble than other benzodiazepines (e.g., diazepam)
Steep dose-response curve
Shorter half-life
Little irritation on injection
Midazolam
antagonist to reverse the effects of benzodiazepines - short duration of action
Flumazenil
mu opioid rc agonist, most commonly used agonist
Fentanyl
used to reverse actions of opiates; possible to reverse respiratory depressant action while maintaing some analgesia
naloxone
blocks NMDA receptor/channels in a manner similar to phencyclidine (PCP)
Rapidly causes loss of consciousness after IV injection
Causes analgesia
Maintenance of pharyngeal and laryngeal reflexes
Does not depress respiration
Bronchial relaxation
High therapeutic index (ratio of TD50 or LD50 to ED50) (in other words it’s safe)
Analgesia
Birth, vaginal delivery
changing of bandages in burn patients
Induction of Anesthesia
Not used much in this country in comparison with other agents in adults
Ketamine
Short acting intravenous anesthetic used for general anesthesia or sedation
Modulator of GABAA receptor
Less respiratory depressant
Less histamine liberation
No appreciable cardiovascular effects
ideal induction agent for patients who are haemodynamically unstable and in emergency
only anesthetic agents able to decrease intracranial pressure and maintain a normal arterial pressure.
Etomidate
Major ADEs of etomidate
seizures, myoclonus, adrenocortical suppression (caution in critically ill trauma pts)
Sedative for critically ill or injured patients
Shorted time for extubation
Always accompanied by respiratory depression
a2 adrenergic agonist can induce hypotension and bradycardia if given as bolus
Dexmedetomidine
