Pharmacology - Chapter 27 - General Anesthetics Flashcards
Analgesia - def
loss of sensibility to pain.
Anesthesia - def
refers not only to loss of pain but to loss of all other sensations.
General anesthetics should produce… (2)
Unconsciousness and lack of response to all painful stimuli.
What are the two groups of general anesthetics?
Inhalation and intravenous.
An IDEAL inhalation anesthetic produces….(4)
Unconsciousness, analgesia, muscle relaxation, amnesia.
The properties of an idea inhalation anesthetic are… (3)
Brief and pleasant, easy to titrate (depth could be raised or lowered easily) and margin of safety is large.
The idea general anesthetic does exist. T/F?
False. It does not exist.
Balanced anesthesia - def
the use of combinations of drugs to accomplish what inhalation anesthetic can not do alone.
What are some agents used for balanced anesthetics?
Short acting barbituates,neuromuscular blocking agents, opioids and nitrous oxide.
What are the 4 stages of anesthesia?
- Stage of analgesia.
- Stage of delirium.
- Stage of surgical anesthesia.
- Stage of medullary paralysis.
Stage of Analgesia - def
begins with onset of anesthetic administration and extends until consciousness is lost. Some major surgeries can be performed here.
Stage of Delirium - def
includes memory loss, hallucinations, etc. Begins with loss of consciousness and extends to the onset of the stage of surgical anesthesia. Characterized by delirious excitement and reflex muscle activity and irregular respiration.
Stage of Surgical Anesthesia - def
most surgeries performed here. Extends from end of stage 2 to the point where spontaneous respiration ceases. Deep unconsciousness. Suppression of certain reflexes. etc.
Stage of Medullary Paralysis - def
begins when all spontaneous respiration is lost. Results from anesthetic overdose. Death can occur from circulatory collapse.
MAC - def
Minimum Alveolar Concentration - index of inhalation anesthetic potency. MAC of drug in the alveolar air that will produce immobility in 50% of patients exposed to a painful stimulus.
Low MAC = ____.
High anesthetic potency.
To produce therapeutic effects, an inhalation anesthetic must reach _____ ….
a concentration in the CNS that is sufficient to suppress neural excitability.
Distribution of anesthetic - what gets it first and what gets it last?
First is the vital organs - like the brain, heart, etc. Last is the adipose tissue.
General Anesthetic - Adverse Effects (5.)
Respiratory depression, Cardiac depression, Malignant hyperthermia, aspiration of gastric contents, hepatotoxicity.
Adjuncts to inhalation anesthetic complement ___ effects of inhalation anesthetics and ____ adverse effects.
Complement/Counteract.
Preanesthetic Medications - what do they do?
Reduce anxiety, produce properative amnesia, relief preoperative pain, relieve postoperative pain.
Preanesthetic Meds - What do they do? - Benzodiazepines -
reduce anxiety and promote amnesia.
Preanesthetic Meds - What do they do? - Barbituates
relieve anxiety and induce sedation.
Preanesthetic Meds - What do they do? - Opioids
relieve pain.
Preanesthetic Meds - What do they do? - Clonidine
reduces hypertension and pain.
Preanesthetic Meds - What do they do? - Anticholinergic Drugs
reduce the risk of bradycardia during surgery.
Preanesthetic Meds - What do they do? - Neuromuscular Blocking Agents
induce muscle relaxation.
Preanesthetic Meds - What do they do? - Analgesics
needed to control post-op pain.
Preanesthetic Meds - What do they do? - Antiemetics
suppression of nausea and vomiting.
Preanesthetic Meds - What do they do? - Muscarinic Agonist
Stimulation of muscarinic receptors by bethanechol and relieve abdominal distention and urinary retention in post-op patients.
What are the two basic categories of Inhalation Anesthetics?
Gases - Nitrous Oxide and Volatile Liquids, like Halothane.
Nitrous Oxide - always used alone. T/F?
False. It is never used alone!
There are no serious side effects of NO but it can induce…
nausea and vomiting.
halothane - may cause…
liver failure.
When used in conjunction with inhalation anesthetics, IV agents serve two benefits :
Permit dosage of inhalation to be reduce and produce effects that cannot be achieved with an inhalation agent alone.
Thiopental - Barbiturates - \_\_\_ acting. Produces unconsciousness within \_\_ to \_\_\_ seconds. \_\_\_ lipid soluble. Good for induction of \_\_\_.
Short acting.
10-20 seconds.
Highly lipid soluble.
Unconsciousness.
Diazepam - Benzodiazepines -
slower than ___.
Produce unconsciousness within ___ minute.
Good for __ and ___.
Barbituates.
1 minute.
Unconsciousness and amnesia.
Diazepam - causes ___ and ___ depression.
Cardiovascular/Respiratory.
Propofol -
__ onset (within __ seconds.)
__ duration of action (__ to ___ minutes.)
Good for _____.
rapid onset.
Short duration of action (3-5 minutes.)
mechanical ventilation/endoscopy.
Propofol causes…..profound __ depression and ___.
Respiratory/hypotension.
Ketamine - produces state of _____. Also, (4) things.
Dissociative anesthesia/sedation, immobility, analgesia, and amnesia.
During recovery from ketamine, unpleasant ____ reaction may occur.
Psychological.
Droperidol plus fentanyl (Innovar) - Similar to state of ____/good for ___.
Dissociative anesthesia/good for minor surgery.
Droperidole plus fentanyl - causes __ and ___ depression.
Hypotension/respiratory depression.
