Basic Questions Flashcards
1
Q
When should FFP be used for warfarin reversal?
A
- FFP may be used if surgery is urgent and INR is >1.5
- Vitamin K should be used for elective procedures (including procedures that can be delayed 24 hours)
2
Q
What can happen if excessive anti-cholinesterase medication is given (i.e. neostigmine, edrophonium, etc)?
A
-It can cause a depolarizing blockade! (Similar to succinylcholine)
3
Q
How long should patients wait after receiving drug-eluting stents vs. bare-metal stents before undergoing surgery?
A
- It depends. For elective cases: wait 30 days for bare-metal stents, and wait 365 days for DES.
- For drug-eluting stents, urgent cases can proceed after 180 days. (If pt. will experience bad outcome w/ surgical delay).
- A case should be delayed 14 days if pt. has had a recent balloon angioplasty
4
Q
What can trigger laryngospasm?
A
- It can be triggered by pain, abdominal/visceral stimulation, vomitus, respiratory secretions/blood, foreign body in the airway
- It is more common in pediatric pts.
- It is especially high in kids w/ GERD or URI’s within the preceding 4-6 weeks!
5
Q
What is the difference between a case-control study and a cohort study?
A
- In a cohort study, 2 groups of subjects are separated before the intervention is given (i.e. vitamin C to reduce viral illness)
- In a case control study, the subjects are separated AFTER the intervention has been given (i.e. pts. that already either had vitamin C or had not)
6
Q
Carbon monoxide cause tissue hypoxia/acidosis by what 3 mechanisms?
A
- Decreased coupling of oxidative phosphorylation/decreased ATP production
- Increased lactate production
- Leftward shift of oxygen-hemoglobin dissociation curve
7
Q
What 3 things increase MAC?
A
- Hyperthermia/hypernatremia
- Chronic ethanol abuse
- Increased central neurotransmitter levels (MAOI’s, amphetamines, cocaine, ephedrine, levodopa)
8
Q
Maximum allowable doses for local anesthetics?
A
Bupivicaine (plain) 2.5 mg/kg Bupivicaine (w/ epi), Ropivicaine (plain) 3 mg/kg Lidocaine (plain) 5 mg/kg Lidocaine (w/ epi) 7 mg/kg Chloroprocaine (plain) 12 mg/kg
9
Q
What are presenting signs of sodium nitroprusside toxicity?
A
- Flushing
- Elevated mixed venous oxygen
- Metabolic acidosis
- Tachyphylaxis to SNP
- Due to toxicity from SNP’s metabolic byproducts: cyanide and thiocyanate
- Treatment is amyl nitrate (coverts Hb to MetHb which binds cyanide)
10
Q
What 3 metabolic abnormalities occur w/ respiratory alkalosis?
A
- Hypocalcemia
- Hypokalemia
- Hypophosphatemia
11
Q
Which patients are most at risk when performing neuraxial anesthesia?
A
Pts. w/ space-occupying extradural lesions or those that reduce the cross-sectional area of the spinal cord (i.e. spinal stenosis).
-They are most at risk for new or worsening neurologic injury
12
Q
What are acid-base abnormalities in alcoholics?
A
- HYPOkalemia/hypomagnesemia/hyponatremia
- HYPERuricemia
- Metabolic acidosis
- Respiratory alkalosis
13
Q
What happens w/ decreasing/increasing temperatures and gas solubility in blood?
A
- As temperature decreases, gases become more soluble in blood. This means the partial pressure of the gas will DECREASE!!
- The opposite will happen w/ increases in temperature.
- *Blood pH will increase w/ decreasing temperatures**
14
Q
What order does blockade occur in after local anesthetic administration? What are the levels of pain/sympathetic/motor blockade?
A
- First to last: B fibers, A fibers, then C fibers (BAC). Recovery is in reverse order (CAB)
- ‘Sympathetic People Matter’ (sympathetics are 2-4 levels higher than motor block, pain blockade levels are 2-3 levels higher than motor)
15
Q
What receptors does dopamine act on at low/moderate/high doses?
A
- Low: D1 dopamine receptors (vasodilation of coronary/renal/mesenteric vasculature)
- Moderate: Beta-1 receptors
- High: Alpha-1 receptors
16
Q
What are the percentages of data for 1, 2, and 3 standard deviations from the mean (assuming a normal distribution)?
A
-Plus/minus 1 standard deviation: 68%
“ “ 2 standard deviations: 95%
“ “ 3 standard deviations: 99%
17
Q
What kind of metabolism does lorazepam undergo?
A
- Phase 2 reaction (in the liver). It undergoes glucuronidation
- *Midazolam and diazepam undergo Phase I reaction (oxidation/reduction)
18
Q
How does an intrathoracid/extrathoracid lesion affect inspiration/exhalation?
A
- A variable extrathoracic lesion causes impairment during INHALATION
- A variable intrathoracic lesion causes impairment during EXHALATION
- A fixed upper airway obstruction or large airway obstruction causes impairment of both inspiratory and expiratory phases (Foreign body, tracheal stenosis, etc.)
19
Q
What 2 agents are unaffected by pseudocholinesterase deficiency? What agents are metabolized by pseudocholinesterase?
A
- Remifentanyl and esmolol are metabolized by non-specific blood and tissue esterases and are not affected by pseudocholinesterase deficiency
- Succinylcholine, mivacurium, ester local anesthetics, cocaine and heroin are metabolized by pseudocholinesterase
20
Q
What are the 3 mechanisms of nitroprusside toxicity?
A
- Cyanide ions bind to cytochrome-C oxidase and inhibit cellular aerobic respiration
- Formation of cyanmethemoglobin (which cannot carry oxygen)
- Thiocyanate production (which causes CNS-related effects)
21
Q
What is the preferred therapy for urgent reversal of warfarin therapy?
A
Prothrombin complex concentrate (PCC) along with vitamin K administration
22
Q
What are the 3 phases of coagulation?
A
- Primary hemostasis (platelets form a clot to plug vascular injury)
- Coagulation (fibrin forms mesh over the clot to stabilize it)
- Fibrinolysis (after the injury is repaired, the clot is broken down)
23
Q
How is the time constant calculated?
A
It is the volume or capacity of the circuit (Vc) divided by the fresh gas flow (FGF). Vc/FGF
24
Q
How long does it take after an episode of acute hypotension/hypovolemia for angiotensin-II-mediated vasoconstriction to occur?
A
Within 20 minutes after the onset of hypotension/hypovolemia
25
When should perioperative stress-dose steroids be given?
- They should be given to patients who take >10 mg prednisone per day, or patients who had previously been taking that dose less than 3 months before surgery. (If the last dose was >3 months before surgery, they do NOT need supplementation)
* *Patients taking high-dose steroids for immunosuppression do NOT need perioperative supplementation**
26
What are the 3 most important factors which determine level of spinal blockade?
1. Drug dosage
2. Drug baricity
3. Patient positioning
27
Meperidine is similar to what molecule?
Atropine. Increased heart rate may occur as a side effect of meperidine administration
28
What 4 things cause (gas) laminar flow to become turbulent?
1. High gas flow rates
2. Sharp angles/branch points within a tube
3. Increase in diameter of a tube
4. Decreasing viscosity of a gas
29
How long should patients wait for elective surgery after having an MI/bare-metal stent/drug-eluting stent?
- After MI: wait 14 days (after balloon angioplasty)
- After BMS: wait 30 days
- After MI (w/o coronary intervention): wait 60 days
- After DES wait 360 days
30
Where does cardiac sympathetic innervation originate from?
T1-T4.
| -It is associated w/ alpha-1, beta-1, and beta-2 adrenergic receptors
31
What is the difference between an acute and delayed hemolytic transfusion reaction?
- Acute reactions are almost always due to ABO incompatibility
- Delayed reactions are usually secondary to antibodies associated w/ Rh, Kidd, or Kell systems.
- Both are the result of RECIPIENT antibody and complement attack on donor cells.
*Delayed reactions can take up to 21 days!**
32
What are the 2 types of starches? Which is associated w/ lower risk of coagulopathies?
- Hetastarches and tetrastarches
| - Tetrastarches are newer and lower molecular weight. They are associated w/ lower risk of coagulopathy.
33
Anti-arrhythmic of choice in CHF/low ejection fraction? Side effects?
Amiodarone
-Bradycardia, hypotension, hypothyroidism/hyperthyroid storm, pulmonary toxicity, prolonged QT, elevated LFTs, tissue deposits (blue-grey appearance)
34
What steps should be taken for a patient that has aspirated gastric contents w/ an LMA?
1. Increase FiO2 to 100%
2. Deepen anesthesia
3. Place patient in head-down position
-Suctioning should be performed and severity of aspiration assessed using fiberoptic bronchoscopy
35
What 3 receptors does nitrous oxide act on?
'AND'
1. Alpha-adrenergic receptors (analgesia and sympathomimetic effects)
2. NMDA (analgesia and CNS-depression)
3. Dopamine (analgesia via downstream induction of opioid release)
36
St. John's Wort drug interactions?
It is an herbal anti-depressant that induces the CYP enzymes, which can over-metabolize lidocaine, alfentanil, midazolam, cyclosporine, and warfarin.
-It should be stopped at least 5 days prior to any surgical operation
37
What are the 3 main determinants of myocardial oxygen demand?
1. Wall tension
2. Heart rate
3. Contractility
38
What is the treatment for citrate toxicity?
Calcium
39
What are the goals for patients w/ aortic stenosis/regurgitation?
- Aortic Stenosis: Normal sinus rhythm should be maintained; a normal to slower HR is good to allow for ventricular filling. Maintain contractility, maintain adequate preload. Afterload must be maintained distal to stenotic lesion to ensure coronary perfusion
- Aortic Regurgitation: HR must be kept above 80 to prevent increased time for regurg. Maintain contractility. Need adequate preload to move enough volume forward, but do not overload-this will increase regurgitant volume. Lower afterload-this should prevent more regurgitation.
40
What are the values for mild/moderate/severe ARDS?
Mild: PaO2/FiO2 ratio of 200-300
Moderate: 100-200
Severe: <100
41
What is the role of the carotid body and carotid sinus?
-Carotid body: chemoreceptor
-Carotid sinus: baroreceptor (think 'Sinus Pressure')
(The carotid sinus causes increased parasympathetic discharge)
42
What is seen in primary hyperthyroidism?
Elevated T3/T4 (free and total), elevated thyroid hormone binding ratio, and a low or normal TSH
43
A full tank of N2O is how many liters/psi?
-1590 L
-745 psig
(Pressure will remain at 745 psi until all liquified gas is used up)
44
What are the top 3 causes of death associated w/ blood product transfusions?
1. TRALI
2. Hemolytic transfusion reactions (non-ABO> ABO)
3. Infection/transfusion-associated sepsis
45
Acute hypoxemia immediately following trendelenburg position is most likely due to what?
- Endobronchial intubation
- A shift of the diaphragm upward will result in a cephalad shift of the tracheobronchial tree- this may cause an ET tube to move further into the trachea and into the right main stem bronchus
46
What are the effects of dexmedetomidine?
- It provides sedation/anxiolysis/hypnosis/analgesia/sympatholysis
- It decreases HR, SVR, CO, and BP
- It also decreases incidence of perioperative myocardial ischemia and reduces perioperative opioid requirements
47
What structures are HYPOechoic?
- Structures such as blood (which have a high water content) reflect little of an ultrasound's beam
- Structures w/ low water content (bone and tendon) reflect more of an ultrasound's beam and appear hyper echoic.
* *Air reflects a significant amount of the beam back**
48
What is the order of least-to-most soluble volatile anesthetic?
Desflurane, Nitrous Oxide, Sevoflurane, Isoflurane, Halothane
49
Pseudocholinesterase deficiency affects what 2 drugs?
- Succinylcholine and mivacurium. Deficiency prolongs the actions of both paralytics.
- Echothiophate also inhibits pseudocholinesterase- it can cause up to a 95% decrease in pseudocholinesterase function
50
How is the standard error (standard error of the mean) calculated?
SE= standard deviation/square root of 'N' (sample size)
51
What is the order of non-depolarizing muscle relaxant potentiation by volatile anesthetics?
Des>Sevo>Iso>Halothane>TIVA
| -This is b/c desflurane is less potent, therefore, more of the drug is within the blood compared to sevo and iso
52
Laminar/Turbulent flow is affected by what gas factor?
- Laminar flow is primarily affected by gas viscosity (Poiseuille)
- Turbulent flow is primarily affected by gas density (Graham's law)
53
What is a type I and type II error?
Type I: incorrectly accepting the alternate hypothesis
| Type II: incorrectly accepting the null hypothesis
54
Heat transfer from the patient to the environment occurs through what 4 mechanisms?
1. Radiation: surfaces the pt. is in contact with will absorb radiated heat
2. Convection: thin layer of air next to skin acts as an insulator- OR air is exchanged and disrupts this layer
3. Conduction: transmission of body heat through conducting medium
4. Evaporation: sterile prep solutions are applied and liquid changes into vapor, resulting in decreased temp.
* *Radiation and convection are the 2 biggest contributors to heat loss**
55
Which volatile agent undergoes the most extensive metabolism?
Sevoflurane (5-8%)
| From most to least: sevo, iso, des
56
What is the stimulus for the carotid body chemoreceptors?
They are primarily responsive to reductions in arterial partial pressure of oxygen (PaO2)
-They increase minute ventilation in response to decreases in PaO2 below 60-65 mm Hg
57
What are the 4 depths of anesthesia?
1. Minimal Sedation: normal response to verbal stimulation
2. Moderate: purposeful response to verbal/tactile stimulation
3. Deep: purposeful response to repeated or painful stimulation. Spontaneous ventilation may be inadequate and airway intervention may be required
4. General Anesthesia: unable to arouse even w/ painful stimulus. Spontaneous ventilation is frequently inadequate- airway intervention is often required. Cardiovascular function may be impaired.
58
What are the current recommendations for preoperative ACE inhibitor use and treatment for refractory hypotension?
- Current evidence states to continue ACE inhibitors on the day of surgery
- Refractory hypotension should be treated w/ NE
59
What functions are lost in anterior spinal artery syndrome?
Loss of: motor, temperature, and pain
| -Proprioception and vibratory senses are preserved
60
What is the most common cardiovascular side effect of succinylcholine?
-Bradycardia is most likely to occur w/ repeated dosing and in children
61
What are the 4 potassium-sparing diuretics?
'EAST'
- Eplerenone
- Amiloride
- Spironolactone
- Triamterene
62
What are the 4 natural compounds that interfere with platelet function?
- Garlic
- Ginger
- Ginko
- Vitamin E
63
What does a negative pressure test evaluate?
-It allows differentiation between leaks in the machine (low-pressure circuit) and leaks in the breathing system
64
In data sets that are not normally distributed (i.e. children and older adults), what is the best value to use for measurement of central tendency?
-The MEDIAN
65
What are contraindications (3) for ACE inhibitors?
ACE inhibitors are contraindicated in:
1. Pts. w/ renal artery stenosis
2. Pregnancy (teratogenic)
3. Pts. w/ history of angioedema (whether related to ACE-inhibitors or not)
66
What is the formula for arterial oxygen content?
Arterial Oxygen Content (CaO2)=
| Hgb x 1.36 x SaO2) + (0.003 x PaO2
67
What is the association with turbulent/laminar flow and gas properties?
'TD' and 'LV'
- Turbulent gas flow: resistance increases w/ increasing gas DENSITY
- Laminar flow: resistance increases w/ increasing gas VISCOSITY
68
What is measured for Child-Pugh and MELD scores?
MELD: 'I Crush Beer Daily'
- INR
- Creatinine
- Bilirubin
- Dialysis
```
Child-Pugh 'Pour Another Beer At Eleven'
PT
Ascites
Bilirubin
Albumin
Encephalopathy
```
69
What happens at high altitudes when a desflurane vaporizer is used? How do you adjust the settings?
Most desflurane vaporizers deliver the anesthetic at a constant percent concentration (NOT a constant partial pressure)
-The formula is: Required dial setting=
desired % x (760 mm Hg/current atmosphere mm Hg)
70
What 3 medications can decrease incidence of emergence delirium w/ ketamine administration?
Benzodiazepines, barbiturates, or propofol
71
What does increased peak inspiratory pressure indicate?
Both peak inspiratory and plateau pressure increase when compliance decreases (increased elastic resistance). When airway resistance increases, only PEAK inspiratory pressure increases.
(For example, bronchospasm will cause an increase in peak inspiratory pressure w/ a mostly unchanged plateau pressure)
72
What 3 medications can be used to treat opioid-induced biliary colic?
Naloxone, atropine, and papaverine
73
What 3 medications are GP IIb-IIIa receptor inhibitors?
'EAT'
- Eptifibatide
- Abciximab
- Tirofiban
74
What are the most efficient Mapleson systems for spontaneous/controlled ventilation?
'All Dogs Can Bite' (Spontaneous)
A>D>C>B
'Dead Bodies Can't Argue (Controlled)
D>B>C>A
75
What are some agents that cause methemoglobinemia? What is the treatment? For pts. w/ G6PD deficiency?
Prilocaine and benzocaine are local anesthetics known to induce methemoglobinemia. They are commonly used for upper airway topicalization for awake flexible bronchoscopy and intubation.
-Methylene blue is the primary treatment. For pts. w/ G6PD deficiency, use ascorbic acid (vitamin C)
76
What opioid compounds can cause neuroexcitatory/neuro-depressive effects in pts. w/ renal failure?
- Hydromorphone-3 glucuronide (inactive metabolite)
- Normeperidine (ACTIVE metabolite)
- Morphine-6 glucuronide (ACTIVE metabolite)
77
What are 'active cardiac conditions'? (4) When is an MI considered 'old' vs. recent?
1. Unstable coronary syndromes (angina class 3 or 4, recent MI)
2. Decompensated heart failure
3. Significant arrhythmias (high-grade AV block, Moritz type II, 3rd-degree AV block, etc)
4. Severe vavular disease (aortic stenosis- mean pressure gradient >40, aortic valve <1.0 cm, symptomatic mitral stenosis)
-An 'old' MI is defined as occurring greater than 30 days prior. It is considered a 'clinical risk factor', but not an active cardiac condition.
78
What is the conversion factor for calculating the difference in BP between 2 sites?
-The difference in BP at 2 different sites equals the height difference in centimeters multiplied by the conversion factor 0.75
79
What is the formula for saturated vapor pressure?
Agent SVP= (agent vapor volume/carrier gas volume +agent vapor volume) x total pressure (760 mm Hg)
80
What is the vasopressor of choice in patients w/ traumatic brain injury, increased urine output, and hypotension?
Vasopressin (for neurogenic diabetes insipidus following TBI)
81
What are the 4 causes of a sudden drop in end-tidal CO2?
1. Cardiovascular collapse
2. Massive venous-air embolism/large PE
3. Esophageal intubation
4. Circuit or sampling line disconnection/dislodged or kinked ET tube
82
After giving supplemental O2 to a patient w/ COPD, why does hypercapnea develop?
It is due primarily to ventillation-perfusion mismatching, driven by inhibition of hypoxic pulmonary vasoconstriction. (Areas of poorly ventilated lung 'steal' blood from the areas that are well ventilated, resulting in higher amount of dead space and higher CO2)
83
What symptoms can natural licorice cause?
It can induce hyper-aldosterone like effects: hypokalemia, HTN, hypernatremia, fluid overload, and metabolic alkalosis.
84
Where does ketamine work in low and high doses?
Analgesic properties are primarily NMDA receptor-mediated at low doses, with more opioid receptor-mediated effects at higher doses.
85
Which inhalational agents are affected most by right-to-left shunts?
The less-soluble agents (N2O>Des>Sevo>Iso>Halo)
86
What are the afferent and efferent nerves involved in the laryngospasm reflex?
Afferent: superior laryngeal nerve (internal branch)
Efferent: recurrent laryngeal nerve
87
How does lowering or raising a transducer relative to the patient affect readings?
- Raising the transducer relative to the patient will decrease the BP reading
- Lowering the transducer relative to the patient will increase the BP reading
*A 10 cm change in height will alter the pressure reading by 7.5 mmHg**
88
Differences between alfentanil and fentanyl?
'Rule of 4'
- Alfentanil is about 4 times faster onset
- Alfentanil lasts about 1/4 the duration
- Alfentanil is about 1/4 the potency (need 4x the dose of fentanyl)
89
What speeds up elimination of drugs that undergo Hoffman elimination?
Reaction speed is increased w/ higher pH and higher temperature (Cisatracurium)
90
How long of a wait after low-molecular weight heparin dose and placement of neuraxial anesthesia? When can it be restarted after surgery?
- For once daily dosing of LMWH: wait 10-12 hours. Restart LMWH 6-8 hours postoperatively.
- For twice daily dosing: wait 24 hours. Restart LMWH 24 hours postoperatively. (Must pull the epidural before starting and wait at least 2 hours afterward)
91
Which volatile anesthetic causes the most potentiation of neuromuscular blockade?
Desflurane
92
How much fibrinogen does cryoprecipitate contain? What factors does it have?
- It contains approx. 200 mg/unit of fibrinogen
| - It is high in factors 8, 13, fibrinogen, and Von Willebrand factor
93
How does a non-hemolytic febrile transfusion reaction occur?
It occurs because recipient antibodies cause lysis of donor leukocytes found in the red cell transfusion product
94
Relationship for turbulent vs. laminary flow and important factors affecting each?
'TD in LV' (For Raiders)
- High flow tends to be turbulent and DENSITY is the more important factor affecting flow
- Low flow tends to be laminar, and VISCOSITY is the more important factor affecting flow
95
What level of PEEP is recommended in obese patients after intubation?
A PEEP of >5 cm H2O is recommended. Also tidal volumes of 6-8 mL/kg of predicted body weight, low FiO2, and recruitment maneuvers should all be utilized when possible
96
What are high risk factors for endocarditis (in patients undergoing surgical procedures)? (6) What are the high-risk procedures? (3)
1. Prosthetic heart valves
2. History of infective endocarditis
3. Unrepaired congenital heart defect
4. Repaired congenital heart defect (first 6 months after repair)
5. Repaired congenital heart defect w/ residual defect(s)
6. Valvular disease in a transplanted heart
1. Dental Work (gingival tissue manipulation or perforation of oral mucosa)
2. Respiratory tract procedures w/ incision or biopsy
3. Skin or musculoskeletal tissue procedures
(GI/GU, vaginal/c-sections do NOT require prophylaxis)
97
For what types of surgery (5) should aspirin be held?
- Pts. taking daily aspirin should generally continue the medication preoperatively.
- Aspirin should be held prior to:
1. Intracranial neurosurgical procedures
2. Middle ear surgery
3. Posterior eye surgery
4. Intramedullary spine surgeries
5. Prostate surgeries
98
Which antibiotics (5) cause prolonged paralysis when a neuromuscular blocking drug is given?
1. Aminoglycosides (Gentamycin/neo/strepto)
2. Polymyxins
3. Tetracyclines
4. Lincomycin
5. Clindamycin
99
Aspirin inhibits what enzyme? The synthesis of which compound is then inhibited?
Aspirin irreversibly inhibits COX, thereby preventing synthesis of thromboxane-A2 (which inhibits platelet aggregation)
100
What are chronic effects of amiodarone therapy?
Thyroid, Lungs, Liver
- Can cause hypo/hyperthyroidism
- Chronic interstitial pneumonitis
- Elevated LFT's
*Can also cause a blue/grey skin discoloration**
101
What are risk factors (5) for emergence reactions after receiving ketamine?
1. Age (adults are more likely than children)
2. Gender (females have higher incidence)
3. Dosage (larger doses w/ rapid administration increase risk)
4. Psychological Susceptibility (extroverts, neurotic personalities are at higher risk)
5. Concurrent Medications (multiple medications increase incidence- benzodiazepines can be given prior to ketamine to decrease risk)
102
How does fenoldopam work?
It is a selective D1 (dopamine) receptor agonist w/ direct natriuretic and diuretic properties. It promotes an increase in creatinine clearance and has been used as a 'renal protector' when renal vasoconstriction is anticipated
103
What 3 substances do NOT undergo metabolism in the lungs?
'DIE'
1. Dopamine
2. Isoproterenol
3. Epinephrine
104
Does lithium prolong or decrease action of neuromuscular blockers?
- It prolongs both depolarizing and non-depolarizing neuromuscular blockers.
- Lithium may decrease MAC b/c it blocks brainstem release of NE, epinephrine, and dopamine
105
How do prostaglandins and angiotensin II affect the renal vasculature? How can NSAIDs be dangerous to the kidney?
- Prostaglandins vasodilate the AFFERENT arteriole, increasing glomerular capillary perfusion
- Angiotensin II vasoconstricts the EFFERENT arteriole to improve glomerular perfusion (this improves perfusion as long as the afferent arteriole remains dilated!)
*NSAIDs inhibit the production of prostaglandins and can be potentially nephrotoxic if a pt. is hypovolemic or on ACE inhibitors, etc**
106
What is the difference between zero-order and first-order kinetics?
- Zero Order: the enzyme or enzymes that metabolize a drug are working at maximum capacity- drug metabolism is independent of drug concentration (b/c the enzymes are saturated). The rate of elimination is constant (linear). (A constant AMOUNT of medication is removed per unit time)
- First Order: Rate of metabolism is proportional to liver blood flow. Drug elimination is proportional to drug concentration. Elimination is exponential. (A constant percentage of medication is removed per unit time)
107
What is the treatment for ACE-inhibitor refractory hypotension?
- IV fluids should be given pre-induction, etomidate for stabilization of MAP
- NE is preferred over vasopressin for refractory hypotension (if phenylephrine/ephedrine/glycopyrrolate are ineffective initially)
108
What are risk factors (3) for postoperative cognitive dysfunction?
1. Advancing age
2. Lower educational level
3. History of previous CVA w/ no residual impairment
109
Chronic opioid therapy affects hormonal levels in what way?
- Increased prolactin
| - Decreased: testosterone, estrogen, cortisol, LH, FSH
110
What is the best treatment for high spinal blockade (above T5)-induced nausea?
Atropine is almost universally effective in treating nausea (parasympathetic-mediated nausea)
111
What are contraindications for EMLA use?
1. Allergy to amide anesthetics
2. Concomitant class III anti-arrhythmic drugs
3. Congenital or idiopathic methemoglobinemia
4. Infants (<12 months) receiving treatment w/ methemoglobin-inducing agents
112
What are preoperative risk factors (6) for post-operative acute renal failure (following non-cariac surgery) in patients w/ normal renal function?
1. Age 59 or higher
2. BMI 32 or higher
3. Chronic liver disease
4. COPD requiring chronic bronchodilator use
5. Peripheral vascular occlusive disease
6. High risk/emergency surgery
113
What is the duration of action for cimetidine, ranitidine, and famotidine?
'CRF'
Cimetidine: 3-4 hours
Ranitidine: 9-10 hours
Famotidine: 10-12 hours
114
How do volatile anesthetics affect cerebral blood flow/cerebral metabolic rate?
They decrease cerebral metabolic rate, while increasing cerebral blood flow via a direct cerebral vasodilating effect
115
What is the order for electrolyte flow during the myocyte action potential?
'Nine Koalas Cause Kookiness'
Na (in)
K (out)
Ca (in)
K (out)
116
What is the treatment for medication-induced acute dystonic reactions?
- Anticholinergic medications (benztropine or diphenhydramine)
- Benzodiazepines can be used for ADR's refractory to anticholinergics
117
What nerve is the afferent limb for the laryngospasm reflex?
The internal branch of the superior laryngeal nerve
118
What are adverse effects (4) of giving bicarbonate?
- Increases in CO2/End-tidal CO2
- Increases in ICP
- Transient decreases in Ca/K
- Hypotension (due to hypocalcemia, ventricular depressant effects, redistribution of blood to the pulmonary vasculature)
119
What are the hemodynamic goals for patients w/ aortic stenosis?
- Maintaining afterload and sinus rhythm while avoiding tachycardia
- Maintain left ventricle preload
* A heart rate of 55-70 beats/min is ideal
* Maintenance of sinus rhythm is important b/c patients w/ AS rely heavily on atrial contraction for ventricular filling
120
Where does the conus modulars/dural sac usually terminate in newborns and adults, respectively?
Newborns: conus medullaris ends at L3, dural sac ends at S3
Adults: conus medullaris: L1-L2, dural sac: S1-S2
121
For what conditions should neuromuscular blocking drugs have the intubating dose increased?
-Cirrhosis, CHF, Renal failure
- Neuromuscular blocking agents are highly water-soluble; an increase in body water requires an increased intubating dose
- Maintenance doses should be reduced in pts. w/ liver disease
122
How is the P50 (oxyhemoglobin) different between newborns, children, and adults?
P50 is lowest in newborns (18 mm Hg)
P50 is highest in children over 12 months of age (30)
-After 10 years of age, P50 decreases to adult level (27)
123
What piece of equipment prevents microshock to the patient?
- The equipment ground wire
| - The ground fault interrupter can prevent MACROshocks, but does not reliably prevent microshocks
124
What receptor does meperidine affect for its beneficial effects?
The Kappa opioid receptor
125
How is mivacurium metabolized?
By pseudocholinesterase
| -Burn patients have decreased levels of pseudocholinesterase
126
When reading thromboelastography (TEG) tracings, what should be given for abnormal R, K, and MA values?
- R value prolonged: give FFP
- K value prolonged: give cryoprecipitate
- MA value decreased: give platelets
-If it is a 'teardrop' appearance, give anti-fibrinolytics
127
How does hyperparathyroidism affect the dose of non-depolarizing neuromuscular blockings agents?
Hyperparathyroidism is associated w/ muscle weakness and hypercalcemia. The effect of non-depolarizing NMB's are unpredictable in this population- thus, it is recommended to use SMALLER initial doses and titrate to effect.
128
What type of metabolism reactions are cytochrome p450 enzymes involved with?
p450 enzymes are involved in OXIDATION reactions (not reduction or hydrolysis reactions)
129
What are the vapor pressures of volatile anesthetics from greatest to least?
'DIS'
Des>Iso>Sevo
130
What things increase closing capacity?
'ACLS-SO'
Age
Chronic Bronchitis
LV Failure
Smoking
Surgery
Obesity
131
What is the equation to determine how much concentrated solution is required to create a certain volume of a dilute solution?
V1 x C1 = V2 x C2
V1/C1: volume/concentration of initial drug
V2/C2: volume/concentration of dilute drug
132
What are the 2 most important adverse effects of sugammadex? What are other adverse effects?
1. Anaphylaxis/hypersensitivity reactions (nausea, pruritis)
2. Bradycardia (potentially severe)
-Arrhythmias, tachycardias, hypotension, prolongation of PT/INR/PTT, increased risk of unintentional pregnancy (inactivation of hormonal contraceptives)
133
What is adult O2 consumption per minute? How is the FRC calculated in a healthy patient?
- O2 consumption: 3-4 mL/kg/min
| - FRC: 30 mL/kg
134
What devices measure oxygen? What device measures CO2? What device measures pH?
- Clark, galvanic, and paramagnetic electrodes measure oxygen
- Severinghaus electrode measures CO2
- Sanz electrode measures pH
135
How does the location of an a-line transducer affect the BP readings?
- An arterial line does not require BP conversion w/ changes in the height of the catheter, as long as the TRANSDUCER is at the point of reference (the heart).
- A non-invasive BP cuff does require a conversion if it is either above or below the level of the heart, however. (Conversion is 0.75 mm Hg per cm change in height above/below the heart)
136
How is dead space ventilation increased?
It is increased by factors that increase anatomic dead space (neck extension, bronchodilators) or alveolar dead space (upright positioning, positive pressure ventilation, decreased cardiac output, lung pathologies)
137
When should a t-test vs. ANOVA be used?
- Use t-tests for studies involving 2 groups
| - Use ANOVA whenever more than 2 groups are compared
138
What are the receptors (5) within the area pastrami (chemoreceptor trigger zone) that can be antagonized to prevent nausea/vomiting?
1. Dopamine
2. Serotonin
3. Acetylcholine
4. Histamine
5. Neurokinin Type 1 receptors
139
Which is better for spontaneous respirations and controlled ventilation respectively, Mapleson A or D?
- Mapleson A is better for spontAneous respirations
| - Mapleson D is better for controlleD ventilation
140
What is the treatment of anti-cholinergic syndrome produced by atropine or scopolamine?
Physostigmine
141
Which local anesthetic has the highest potential for cardiac toxicity?
Bupivicaine (B= Bad)
142
SSRI's inhibit which liver enzyme? This affects what drugs?
-SSRI's inhibit CYP2D6, which reduces the activation of prodrugs (codeine, hydrocodone, oxycodone) into their active forms
143
What is the order (from most to least) of nerve fibers that are sensitive to local anesthetics? What is the order of blockade after neuraxial anesthesia?
'BAC' (B fibers are most sensitive, then A. C fibers are the most resistant)
-After neuraxial: 'SSM'
Sympathetics are affected 1st, then sensory/pain, then motor function
144
In patients w/ paralyzed extremities (i.e. paraplegics), how will the paralyzed extremity behave vs. a 'normal' extremity after use of non-depolarizing medications?
-The limb that is truly paralyzed (i.e. lower extremities) will show an increased response (i.e. higher train of 4 ratio) vs. the normal extremities
145
What neuromuscular blocking agent is eliminated primarily by the kidney?
Pancuronium
| -It should be avoided in renal failure
146
What is the formula for calculating volume of liquid anesthetic consumed in 1 hour?
Liquid volatile anesthetic (mL/hr) =
| 3 x fresh gas flow (L/min) x % anesthetic vapor
147
What kind of patients should not receive sugammadex? What drugs are incompatible w/ sugammadex?
- Aside from pts. w/ known hypersensitivity to sugammadex, pediatric pts, pts. w/ severe renal failure, ICU pts.
- Ondansetron, ranitidine, and verapamil should not be given in the same line together w/ sugammadex. The line must first be adequately flushed w/ saline between administration of the medications
148
What is the goal for cerebral perfusion pressure after a traumatic brain injury?
CPP should be kept within the range of 50-70 mm Hg according to current guidelines
149
How is power calculated?
Power= 1-beta
