Anesthetics: general and local - Egleton Flashcards
1
Q
what are two categories of inhalational anesthetics
A
halogenated
non-halogenated
2
Q
name a non-halogenated anesthetics
A
nitrous oxide
3
Q
what is balanced anestheisa
A
making sure the patient stays alive
4
Q
MAC
A
inspired concentration of anesthetic required to produce anesthesia in 1/2 of subjects
5
Q
Name 4 factors that affect MAC
A
age
health status
drug interactions
red hair
6
Q
MAC is measured for what age range? how do you adjust MAC for an infant/child and old age
A
35-40 yrs
increase for infant/child
decrease for old age
7
Q
how would you adjust MAC for someone who has hyperthyroidism and hypothyroidism
A
hyer: increase
hypo: decrease
8
Q
How is potency expressed
A
expressed as minimum alveolar concentration MAC
9
Q
if someone is on sedatives how does one change the dose of MAC
A
decreases
10
Q
if someone is on Amphetamines how does one change the dose of MAC
A
increase
11
Q
how does inhaled anesthesia leave the body
A
lungs
12
Q
how much of the inhaled anesthesia is metabolised
A
minimum
13
Q
what is rate of induction
A
how quickly the gas will induce anesthesia
14
Q
how does increasing concentration of anesthetic in inspired-gas mixture impact rate of induction
A
increase
15
Q
how does increasing alveolar ventilation impact rate of induction
A
increase
16
Q
how does increasing solubility of anesthetic in blood ( blood; gas partition coefficient) impact rate of induction? how?
A
decrease
since its soluble it takes longer for it to distribute
17
Q
how does increasing cardiac output impact rate of induction? explain?
A
decrease
- drugs leave alveolar to bloodstream faster
- respiration rate must match this
- partial pressure in arterial blood becomes lower
18
Q
concentration of agent is directly proportional to what
A
partial pressure
19
Q
anesthetic induction occurs faster with what type of agent
A
agents which are less soluble in blood
20
Q
what is the relationship between lipid solubility and MAC
A
linear
21
Q
what is a special characteristic of nitrous oxide
A
would need a LOT of it to induce complete anesthesia
which is impossible
22
Q
What is the Meyer-Overton Theory
A
anesthetic dissolves in the membrane and “affects” the function of membrane proteins - no specific receptor, no specific antagonist
23
Q
for the Meyer-Overton Theory may impede the breakdown of what and how
A
GABA
- potentiating GABA-increased Cl-influx
- increase K+ efflux; Reduce Na, Ca influx
24
Q
what halogen do you not repeat at intervals less than 2-3 weeks
A
Halothane
25
what are cardiovascular effects of Halothane
Sensitizes heart to catecholamines --> increases risk of arrhythmias
26
what can metabolism of Halothane cause
liberation of hydrocarbons, bromide ion which can result in hypersensitivity reaction and hepatitis
27
Halothane and Succinylcholine increases the risk of what? how do you treat this
malignant hyperthermia: sustained contraction of skeletal muscles; dramatic increase in O2 consumption
- Dantrolene
28
what is the cardiovascular effects of Enflurane
less sensitization of heart to catecholamines and Halothane
29
what is respiratory effects of Enflurane
respiratory depression in dose-dependent manner
30
what are CNS effects of Enlflurane
CNS excitation --> Seizures
31
what are muscular effects of Enflurane
Block ACh effects at NMJ
32
what are cardiovascular effects of Isoflurane
-does not induce arrhythmias
- does not sensitize heart to catecholamines
- does not decrease cardiac output
leads to wide margin cardiac safety
33
what is a respiratory effect of Desflurane
respiratory irritant
34
what is a disadvantage of Sevoflurane
leads to production of toxic compound A
| -Fl- released during metabolism
35
what are two properties of nitrous oxide
potent analgesic
| balances anesthesia
36
what are respiratory effects of Nitrous oxide
at least 30% oxygen should be used with N2O ( limited to 70%; usually less due to other agents.
37
what are cardiovascular effects of nitrous oxide
decreases circulatory effects of halogenated anesthetics
38
what can nitrous oxide cause to the blood
oxidizes cobolt of vitamin B12 --> inhibits methylation of macromolecules --> chronic exposure can cause megaloblastic anemia
39
Nitrous oxide does not cause what
malignant hyperthermia
40
what is the second gas effect
a rapidly absorbed gas increases the rate of uptake of a second anesthetic gas
41
what is the major elimination of inhalation anesthetics
lungs
42
when are intravenous anesthetic agents used and inhalation
IV: rapid induction of anesthesia
| maintained by inhalation agent
43
how well do people recover from Propofol
rapid recovery
44
what are cardiovascular effects of using Propofol? who is prone to them
hypotension
| elderly
45
what is PRIS propofol-related infusion syndrome
```
serious side effect of
dysrhythmia
heart failure
hyperkalemia
lipemia
metabolic acidosis
renal failure
```
46
what happens when propofol is used with opioid
increased sedative or anesthetic effects
| decrease systolic, diastolic and mean arterial pressure and cardiac output
47
what happens when propofol is used with opioid fentanyl
serious bradycardia in pediatric patients
48
what happens when propofol is used with alfentanil
seizure activity in patients without any history of epilespy
49
what are advantages of using Etomidate
- minimal cardiovascular effects
| - decreases cerebrovascular blood flow to brain--> use for brain/neural type surgeries
50
what is a drug example of a barbiturate
Thiopental
51
what are properties of Barbiturates
short acting
used for induction, sedative effects
no analgesia or muscle relaxation
52
How does one recover from Thiopental
redistribution from brain into less vascular regions
53
how do you treat over dose of Barbiturates
you don't
| no antagonists in case of overdose
54
what are 2 contraindications of Barbiturates
Variegate porphyria
| acute intermittent porphyria
55
Porphyria
a rare hereditary disease in which the blood pigment hemoglobin is abnormally metabolized
56
Diazepam, Iorazepam, Midazolam are what type of drugs
Benzodiazepines
57
What do Benzaodiazepines cause
reduce anxiety
facilitates amnesia while causing sedation
prevent convulsions
may depress respiration
58
how might Benzodiazepines depress respiration
increase frequency of channel opening
59
what is a Benzodiazepine antagonist
Flumazenil
60
Fentanyl, Morphine, Sulfentanil are what type of drugs
opioids
61
what type of surgery are opioids used in? what is perseved
cardiac surgery as cardiac output and myocardial contractility are perserved
62
what are some side of effects of opioids
hypotension, respiratory depression, muscle rigidity, prostanesthetic nausea/vomiting
63
Opioids can potentially interact with what other drugs
propofol
| gaseous anesthetics
64
what is an opioid antagonist
naloxone
65
Atropine, Scopolamine, glycopyrrolate are what type of drugs
anticholinergic
66
what anticholinergics used for
combat secretions, prevent vagal effects
67
compare/contrast Scopolamine and Atropine with salivation and heart
Scopolamine better prevents salivation
| Atropine is better preventing bradycardia
68
which anticholingeric does not cross the BBB
Glycopyrrolate
69
mental state where individual appears to be dissociated from environment without complete loss of consciousness
Dissociateive Anesthesia
70
name a dissociative anesthesia drug
Katamine
71
MOA of ketamine
NMDA receptor
72
Ketamine reduces what effects of recovery? who usually gets these
delirium, hallucination, irrational behavior
| in adults, less likely in children
73
what are the 4 stages of Anesthesia
analgesia
Excitement
surgical anesthesia
medullary paralysis
74
Analgesia phase of anesthesia
patient is conscious and conversational
75
what happens in excitement phase? do we want to be in this phase
delirium
tachycardia
violent behavior
NO
76
how can an anesthesiologist prevent stage II
give short acting Barbiturate IV before inhalation anesthesia to avoid Stage II
77
what happens in surgical anesthesia
regular respiration
| relaxation
78
what happens in medullary paralysis
severe depression of respiratory and vasomotor centers
| death
79
what zone do you want to be in for anesthia
surgical anesthesia
80
ketamine is related to what other drug
phencyclidine
81
as you progress through the stages of anesthesia what happens to the brain
increased CNS depression
| accumulation of anesthetic in brain
82
to create loss of sensation without loss of consciousness or impairment of central control of vital function
local anesthetics
83
what are two types of Anesthetic drugs? how do you differentiate between the 2
ester : i
| amide: ii
84
MOA of local anesthetics
bind to Na channel ( internal site)
| reversible inhibition of axonal nerve conduction
85
what types of cells are easier to put under local anesthetics
unmyelinated fibers
| automatic and sensory nerves
86
what metabolizes ester type drugs
esterases, plasma cholinesterases
87
what metabolizes amide type drugs
amidases, liver
88
what are some adverse CNS effects of local anesthesia
```
CNS stimulation ( restlessness) followed by CNS inhibition ( sedation)
headache
```
89
what are some adverse CV effects of local anesthesia
hypotension
| cardiac depression
90
what are some hypersensitivity reactions of local anesthesia? why?
allergic dermatitis or asthamatic attack
| due to ester anesthetics to metabolism ro PABA
91
Epinephrine and Phenylephrine do what as anesthetics
vasoconstrictors
92
properties of vasoconstrictors
slows rate of absorption
decreases drug plasma concentration
less likehood of side effects
93
where should vasoconstrictor not be used
end arteries
| fingers, toes, ears, nose, penis
94
what kind of patients should be receiving epinephrine and Phenylephrine
whom adrenergic stimulation may have adverse effect ( hypertension, ventricular arrhythmias)
95
name a skin topical anesthisa
Benzocaine
96
name a mucous membraine and cornea anesthisa
tetracaine
lidocaine
cocaine
97
what is special about epinephrine and mucous membrane
can penetrate mucous membrane, but not good local anesthetic
98
Iontophoresis
small electrical current forces anesthetic into tissue
99
what is the effect of Epinephrine on infiltration anesthesia
doubles duration of anesthesia
100
what is infiltration anesthesia
anesthetic injected directly into tissues
101
Administered in a series of injections to form a wall of anesthesia encircling operative fields
field block anesthesia
102
what is an advantage of field block anesthesia
less drug for greater area of anesthesia than infiltration
103
what is the effect of nerve block anesthesia
produces large ares of anesthesia with small amount of drug
104
when is spinal anesthesia used
people contraindicated for general lower body surgery
105
what drug is used for Epidural anesthesia
Bupivacaine
106
what is the only anesthetic that causes vasoconstriction
cocaine
107
what is procaine metabolized to
PABA
108
Benzocaine is used to treat what
teething/gum pain
109
where is Lidocaine metabolized
liver
