Pharm Unit 1 Flashcards
Definition of anesthesia?
Lack of feeling or sensation, artificially induced loss of ability to feel pain
What are examples of anesthesia from 4000 to 400 BC?
Plants (poppy, coca leaves), acupuncture, ethylene fumes beneath Apollo’s temple, cannabis vapor, carotid compression
What was Hippocrates view of anesthesia?
None is needed, it is the job of the patient to stay still so that the Dr may do their work (accommodating the operator)
Who wrote the materia medica? What is it?
Dioscordies a surgeon in Nero’s army. It is a pharmacology volume.
Give an example of anesthesia from Roman/Greek times
Mandragora and wine, together had a hallucinogenic effect
What was the change in anesthesia in the middle ages?
Preference for inhaled agents began, such as a mix of opium, mandrake, hemlock, hyposcyamus (L-isomer of atropine) and water. Reversed with vinegar
What was the first volatile anesthetic? What was its problem? Who discovered it?
Diethyl ether, very flammable/explosive. Valerius Cordus
Who invented IV access?
Sir Christopher Wren and Robert Boyle
Who discovered NO?
Joseph Priestly
Who discovered the basic elements and suggested NO for surgical pain control?
Humphry Davy
Which dentist found that NO patients had no recall of pain/injury?
Horace Wells
Who started mixing volatiles with air to improve cyanosis?
Andrews a Chicago surgeon
Who re-visited ether as an anesthetic combined with Whisky?
Crawford Long
First successful demonstration of ether in surgery?
1846 in London (via google search, done by Morton)
Who found a way to purify Ether?
Dr. Robinson Squibb
Other than flammable, what are disadvantages of ether?
Prolonged induction/emergence, high incidence of nausea/vomiting
Who defined pain as actual or potential tissue damage?
Sir James Simpson
Who discovered epidemiology?
Dr. Snow
Who used cocaine for eye surgery?
Dr. Koller
Who did the first regional block with cocaine? Type of block?
Dr. Halsted, Mandibular block
Describe the Bier block
You elevate the arm, let blood drain. Wrap the arm tightly to squeeze out more blood. Inflate a BP cuff to prevent flow of blood into the arm, then inject lidocaine. The arm should stay numb until either the lidocaine is metabolized, or blood flow is restored
1st CRNA?
Sister Mary Bernard
Mother of anesthesia?
Alice Magaw
Who opened one of the earliest anesthesia schools?
Agatha Hodgins
Issue with cyclopropane? Halothane?
C = highly explosive
H = Slow onset and can cause hepatitis. Good because it causes bronchodilation
Compare speeds of Desflurane, Sevoflurane and Isoflurane
Des = fastest onset and emergence
Sevo = in between
Isoflurane = slowest onset/emergence of the three
Who did much of the research on modern volatiles?
Dr. Egar
What causes amnesia?
Stimulation of inhibitory transmission (ACh) or inhibition of stimulatory transmission (GABA)
What is the anesthesia triad?
Amnesia, Analgesia and Muscle relaxation
What is Neurolept anesthesia?
You “screw up the brain” to induce amnesia. Involves lots of anti-psychotics and minimal muscle relaxants/opioids.
What is stage 1 of anesthesia? Each plane?
Stage 1 = beginning of induction to LOC
1st plane = no amnesia/analgesia
2nd plane = amnesia, but only partially analgesic (versed, fentanyl)
3rd plane = complete analgesia/amnesia
What is stage 2 of anesthesia?
LOC to onset of automatic breathing. Eyelash reflex disappears, coughing/vomiting/struggling can still occur. This is when we want people to not bother the patient. Laryngospasm a risk as well. You want to get through this stage as fast as possible
What is stage 3 of anesthesia? Each plane?
Stage 3 = onset of automatic respiration to respiratory paralysis
1st plane = automatic respiration to cessation of eyeball movements
2nd plane = cessation of eyeball movements to beginning of intercostal muscle paralysis. Tear secretion increases
3rd plane = beginning/completion of intercostal muscle paralysis. Pupils dilate, desired plane prior to muscle relaxants
4th plane = complete intercostal paralysis to diaphragmatic paralysis (apnea)
What is stage 4 of anesthesia?
Stoppage of respiration to death
What stages do you extubate at? Why?
1 or 3, 2 has a high incidence rate of laryngospasm, N/V
What stage do you intubate at?
Stage 3
Per lecture, what common pressor agent has a high incidence of tachyphylaxis?
Ephedrine
What is the 1 compartment model?
Drug gets injected, goes to heart, circulates through the central circuit and goes to vessel rich groups, then they can leave and go to other places and then be excreted
What is the 2 compartment model?
Drugs go into the central compartment and then into the periphery and from there can go other places such as fat or proteins prior to excretion.
What drugs are listed as sensitive to first pass metabolism?
Lidocaine, propranolol, demerol, fentanyl, sufentanil, alfentanil
What protein do acidic drugs bind to? Basic?
Acid = albumin
Base = A1-Acid Glycoprotein
Which drugs are generally more inactive, water or lipid soluble?
Water
What metabolizes most of our anesthesia drugs?
Liver microsomal enzymes
What are the primary functions of phase I reactions? Phase II?
Phase I = Redox and hydrolysis to increase drugs in polarity to prepare them for phase II
Phase II = Make drugs more water soluble via some form of a conjugation reaction
What is the primary microsomal enzyme? And the most common of that family?
CYP450, and the most common of that subclass is CYP3A4
Induction vs inhibition?
Induction: enzyme activity is increased leading to a shorter duration of a drug metabolized by the enzyme
Inhibition: enzyme activity is reduced leading to a greater duration
Elimination half-time vs elimination half-life?
HT = time to get rid of 50% from the plasma
HL = time to get rid of 50% from the body (tissues for example, hard to measure)
Context sensitive half time?
This is half-time related to an infusion. Basically, the longer an infusion goes, the longer it takes for its effects to wear off.
Does ionized or non-ionized more easily cross barriers?
Non-ionized
What is the mental trick to remember how to solve ionization problems?
Weak Acid PK after pH (a for after), weak base pK before pH (b for before)
Why would a LA not work for a necrotic limb in regards to pH?
Many LA’s are weak bases, if the pH is too low, the LA is likely to ionize and therefore not work
Definition of chiral?
A molecule with asymmetric centers
What is the term for a right rotation of light? Left?
R = Dextrorotatory
L = Levorotatory
Why do we give anti-anxiety meds in pre-op?
To reduce catecholamine cascade
Sedative vs hypnotic?
S = drug that induces sleep or calm
H = Drug that induces hypnosis or sleep
In regards to an EEG, is even/odd on the left or right?
Odd = left, Even = right
BIS terms: SQI, EMG, EEG and SR?
SQI: signal quality index, want this maxed
EMG: you want none, meaning no muscle movement
EEG: all brain electrical activity into one waveform
SR: suppression ratio, tells us how often the EEG has been flat
Goal BIS range?
40 - 60
What are the 5 main effects of BZDs?
Anxiolysis, sedation, anterograde amnesia, anticonvulsant action and spinal-cord mediated skeletal muscle relaxation
Alpha 1 vs Alpha 2 in a GABA receptor?
Alpha 1 = sedative, amnestic and anti-convulsant
Alpha 2 = anxiolytic and skeletal muscle relaxer
What BZD clears the fastest?
Versed
What BZD is an aspiration risk?
Versed
What BZD can produce an isoelectric baseline?
Valium
What BZD is best for a COPD patient?
Valium
What BZD is not dependent on hepatic enzymes?
Ativan
What BZD is the most potent sedative/amnestic?
Ativan
What BZD is the most potent muscle relaxer?
Valium
What BZD has the slowest onset of action?
Ativan
What BZD does not have active metabolites?
Ativan
Relationship of CBF and CRMO to EEG?
Direct correlation, as CBF and CRMO increase, the EEG waveform number should increase
At what BIS are patients going to be unconscious? At what level do they have less than a 5% chance to return to consciousness within 50 seconds?
Bis less than 58 = unconscious
Bis less than 65 for the 5% chance
What is important to note about the spinal-cord mediated skeletal muscle relaxation with BZDs?
It is not adequate for surgery, you will still need muscle relaxants or paralyzers. It does NOT potentiate NMBD
Why did BZDs replace barbiturates?
Less tolerance, less potential for abuse, fewer and less serious side effects, and do not induce hepatic microsomal enzymes
How does a BZD work?
Binds to a GABA receptor, allows Cl to come in, hyperpolarizing the target and making it harder to excite
What other drugs/chemicals can bind to GABA sites (hint think GABA potentiation)?
Barbiturates, etomidate, propofol and alcohol
In general are BZDS highly/poorly protein bound and water/lipid soluble?
Highly protein bound and highly lipid soluble
What are the general effects of BZDs on the EEG?
Decreased a-alpha activity, antegrade amnesia, some unable to produce isoelectric state
What drugs/chemicals are synergistic with BZDs?
Alcohol, injected anesthetics, opioids, alpha-2 agonists (clonidine, precedex, guanfacine), inhaled anesthetics
What is a potential anecdotal concern with BZDs intraop?
Reduced platelet aggregation
What is the relationship of the imidazole ring to BZD drug availability in pH changes?
If the pH is less than 3.5, the ring is open, water soluble and protonated
If the ph is greater than 4.0, the ring is closed, lipid soluble and non-protonated
Which drugs are known to cause inhibition of P-450 enzymes and decrease BZD metabolism?
Cimetidine, erythromycin, CCBs, anti-fungals and fentanyl
Dosing range for versed in children and adults for sedation?
C = 0.25-0.5 mg/kg Oral (peak 20 - 30 minutes)
A = 1 - 5 mg IV, peak 5 minutes
Induction dose of versed?
0.1 - 0.2 mg/kg IV over 30 - 60 seconds given AFTER 50 - 100 mcg of fentanyl
Post-op dose for sedation for versed?
1 - 7 mg/hr IV
Why is post-op sedation with versed now discouraged?
Markedly delays awakening (active metabolites) and can negatively impact the immune T cells
What BZD is not a vesicant?
Versed
List the BZDs from shortest to longest E1/2 times
Versed (2 hours) < Ativan (14 hours) < Valium (20 - 40 hours)
What is the valium dosage for anti-convulsant actions?
0.1 mg/kg IV
At what dose does valium begin to cause hypercapnia (it is still the BZD of choice for COPD patients)
0.2 mg/kg IV, and in general, the ventilatory depression is countered by the stimulation of the surgery
Which BZD has the most minimal impact on the CV system?
Valium
Induction dose for valium?
0.5 - 1.0 mg/kg IV (decrease by 25 - 50% for elderly)
What is the structural difference of Ativan to Serax?
It has an extra Cl atom
Dosing range for Ativan?
1 - 4 mg IV
What is the metabolism route for flumenazil?
Via hepatic microsomal enzymes in inactive metabolites