General Anethsia Flashcards
What are the two types of anesthetics?
General
Local/regional
True or false: there is not total insensibility with general anesthesia
True–some sensory and even motor function are typically preserved
What is the major disadvantage of general anesthesia?
Disturbance of all organ systems
What are the responses of BP and respiration to general anesthesia?
Decreased
What is the triad of anesthesia?
asleep
Pain-free
Still
What are the six qualities of an ideal anesthetic agent?
Unconsciousness Amnesia Analgesia Muscle relaxation Areflexia Good control
What are the drugs that are administered prior to a procedure to relieve anxiety?
Benzodiazepines (e.g. midazolam)
What are the drugs that are administered prior to a procedure to prevent allergic reactions?
Antihistamines (e.g. diphenhydramine)
What are the drugs that are administered prior to a procedure to prevent n/v?
Antiemetics
e.g. dexamethasone, scopolamine
What are the drugs that are administered prior to a procedure to provide analgesia?
Opioids
e.g. fentanyl, morphine, hydromorphone
What are the drugs that are administered prior to a procedure to prevent bradycardia and secretion?
Atropine
Glycopyrrolate
What are the four phases of general anesthesia?
- Induction phase
- Maintenance phase
- Emergence phase
- Recovery period
What is involved in the induction phase of anesthesia?
Initial administration of a drug, until anesthesia acheieved
What is involved in the maintenance phase of general anesthesia?
Anesthetic concentration is maintained at or above minimum level
What is involved in the emergence phase of general anesthesia?
From sub-optimal concentration in the brain until it reaches zero
(“waking up” period)
What is the recovery phase of general anesthesia?
From discontinuance of anesthetic until full resolution of consciousness and normal function
What is the major hemodynamic response to general anesthesia?
Decreased BP via vasodilation, or decrease in sympathetic tone
What is the major respiratory effects of general anesthetics?
Decreased respirations via elimination of ventilatory drive
What is the cause of hypothermia seen in general anesthesia?
Lowering the core temperature set point at which the vasoconstrictie is activated to defend against heat loss
How do general anesthetics cause n/v?
Activation of the chemoreceptor trigger zone
What are the four stages of anesthesia?
Analgesia
Excitement
Surgical anesthesia
Medullary depression
What is involved in the analgesia stage of anesthesia?
analgesia and amnesia
What is involved in stage II (excitement) stage of anesthesia?
Excitement/delirium
Body is trying to counteract the anesthesia
What is involved in stage III (surgical anesthesia) stage of anesthesia?
Unconsciousness
Regular respiration
What is involved in stage IV (medullary depression stage) of general anesthesia?
Respiratory arrest
Cardiac depression/arrest
No eye movement
What are the two major subtypes of anesthetics?
Inhalable
IV
What type of anesthetic is used for neurosurgical cases?
IV
What is an induction agent? Maintenance agent?
Induction = getting asleep
Maintenance = staying asleep, but may not get to sleep fast
What is the beginning and end of stage III of anesthesia?
Beginning = regular respirations
End = Stopping of respirations
What is the beginning and end of stage IV of anesthesia?
Cessation of respiration
Cardiac arrest
Inhaled anesthetics are usually used as induction or maintenance?
maintenance
IV anesthetics are usually used as induction or maintenance?
Induction
What is balanced anesthesia/
The use of many different drug classes to produce an ideal state of anesthesia
What is anesthetic adjuncts?
Drugs used in addition fot eh anesthetic drug to compliment /supplement the anesthetic and produce a better anesthetic state
What are the four important history bits to obtain, prior to administering anesthesia?
H/o malignant hyperthermia
Cardiac problems
Respiratory disease
Allergies
When does stage 1 begin and end?
Analgesia to LOC
When does stage 2 begin and end
LOC to return of regular respiratory pattern
What are the three ways general anesthetics are thought to work?
- Induce neuronal hyperpolarization
- Increase firing threshold
- Inhibit synaptic transmission and response to released neurotransmitters
What are the three ion channels that general anesthetics are thought to work on, and what is the effect on them?
- Increase GABA-A receptor Cl channel activity
- Activate K channels
- Inhibit glutamate NMDA receptors
What is the effect of general anesthetics on GABA receptors?
Increase the Cl channel activity, causing hyperpolarization
What is the effect of general anesthetics on K channels?
Activates them, resulting in hyperpolarization of neurons