True Learn #1 Flashcards
What medications can cause acute dystonic reactions and what is the treatment?
Metoclopramide and prochlorperazine (DA antagonism) or antipsychotics
Tx: diphenhydramine or benztropine or benzos
How much does cerebral blood flow change with every one Celsius decrease in temperature?
6% decrease
How much does cerebral blood flow change with every 1 mmHg change in PaCO2?
Increase in PaCO2 by 1 mmHg = 3% increase in CBF (linear increase until ~80 mmHg)
At what PaO2 value does cerebral blood flow drastically increase?
PaO2
What percentage of receptors are blocked when you have 1 twitch? 2 twitches? 3? 4?
1: >90% blocked
2: 80-90% blocked
3: 70-80% blocked
4: 65-70% blocked
What is the gold standard used for assessing neuromuscular blockade?
Train of four ratio
What train of four ratio correlates to a sustained head lift for 5 seconds?
T4:T1 height ratio of 0.75
What are some common side effects of sodium bicarbonate?
- Increased EtCO2
- Hypokalemia
- Hypotension
- Cerebral vasodilation, increased ICP
- Transient hypocalcemia
What patients need to have perioperative corticosteroid supplementation?
Those who are taking > 10 mg/day prednisone or previously taking >10 mg/day whose last dose was
What are hormonal side effects noted with chronic opioid therapy?
Decreased testosterone/estrogen/cortisol/LH/FSH, increased prolactin
What is the purpose of a vasoconstrictor prior to attempts at nasal intubations?
- Minimize mucosal bleeding
2. Increases diameter of the nasal passages
What does the glossopharyngeal nerve innervate?
Sensory to posterior 1/3 of tongue, vallecula, anterior surface of epiglottis, and posterior and lateral walls of the pharynx
What does the superior laryngeal nerve innervate?
Sensory from the lower pharynx to the upper part of the larynx (including glottis surface of epiglottis and the aryepiglottic folds)
What does the recurrent laryngeal nerve innervate?
Sensory to the mucosa below vocal cords
What nerve does the superior laryngeal nerve branch from? The recurrent laryngeal?
Both come from the vagus nerve (CN X)
What does blinding study participants eliminate?
Participant bias (Hawthorne effect: groups being studied act differently than they normally would)
What are some complications of brachial artery catheterization?
- Thrombosis
- Infection
- Median nerve injury
What is the typical PaO2 value of an O2 sat of 50%?
27 mmHg
Which drug is metabolized by RBC esterases: esmolol, atenolol, metoprolol, labetalol, propranolol?
Esmolol
Name some cardioselective (beta-1) blockers
BEAM: bisoprolol, esmolol, atenolol, metoprolol
Which drug is renally cleared: esmolol, atenolol, metoprolol, labetalol, propranolol?
Atenolol (“ATNolol”)
What is the formula for static respiratory system compliance?
Cs = Vt / (Ppl - PEEP)
Vt: tidal volume
Ppl: plateau pressure
What is the pathophysiology of negative-pressure pulmonary edema?
- Pulmonary capillary fluid entrainment into the airways from negative intrathoracic pressure
- Reduced hydrostatic pressure of the pulmonary interstitium
- Increased trans-capillary pressure gradiant
What is the pathophysiology of tetanus?
Block release of GABA causing generalized muscle spasms
How long must the suction bulb remain collapsed to pass a negative pressure leak test?
10 seconds or longer
What does the negative pressure test tell us?
The integrity of the low pressure circuit (flow control valves to common gas outlet) + differentiate between leaks in the machine and leaks in the breathing system
A patient with a 40% total body surface area burn 1 week ago with hypoalbuminemia will have lower dose requirements of which med: fentanyl, midazolam, rocuronium, insulin
Midazolam: highly albumin bound so hypoalbuminemia -> more free fraction of benzos
Note: due to increased extrajunctional Ach receptors, they develop resistance to non-depolarizing NMBs
What is the formula for specificity? Sensitivity?
Spec: TN / (TN + FP)
Sens: TP / (TP + FN)
(Horizontal is patient with or without disease, vertical is test results)
Do barbiturates or inhaled anesthetic gases uncouple cerebral blood flow and CMRO2?
Barbiturates do not (will decrease CBF and CMRO2)
Inhaled anesthetics > 1 MAC will increase CBF and decrease CMRO2 (uncouples)
What is the mechanism of action of nicardipine?
Arteriolar vasodilator (decreases LV afterload and SVR with minimal effect on preload), dihydropyridine CCB
What is the mechanism of action of nesiritide?
Recombinant form of BNP -> down-regulates RAAS causing arterial and venous dilation + natriuresis + diuresis
What is the mechanism of action of sodium nitroprusside?
Converts nitric oxide in smooth muscle to increased cGMP -> arteriolar & venous dilator
What is the mechanism of action of nitroglycerin?
Activates cGMP production, venous dilator
Increasing cardiac output does what to the anesthetic uptake of soluble gases?
Increases the uptake of soluble gases more than insoluble gases (isoflurane more than sevoflurane and desflurane); this is different from onset of anesthesia
What is the vapor pressures at 20C of the following: desflurane, isoflurane, sevoflurane
Des: 669 mmHg
Iso: 238 mmHg
Sevo: 157 mmHg
What are the benefits of leukoreduced blood products ?
- Decreased febrile reactions
- Decreased inflammatory mediators
- Decreased CMV transmission
What is the treatment for hypoparathyroidism?
Vitamin D supplementation (to keep serum Ca levels normal)
What is the mechanism of action of PTH?
- Stimulates kidneys to increase Ca reabsorption
- Increases bone resorption of Ca (more Ca in serum)
- Increases renal production of calcitriol (makes the intestines increase Ca absorption)
* it does this and also trashes phosphate
Which cells are most dependent on insulin for glucose uptake: cardiac myocytes, cerebral neurons, hepatocytes, leukocytes
Cardiac myocytes
Cerebral neurons rely on insulin-independent GLUT3 transporters
Why would a patient with COPD hypoventilate if they are given supplemental O2?
COPD patients rely heavily on hypoxic pulmonary vasoconstriction; O2 will inhibit HPV
What is the Haldane effect?
Oxygen induced a rightward shift of the CO2 dissociation curve -> increases pCO2 (normally patients will hyperventilate but COPD patients cannot)
What is the line isolation monitor?
It protects persons from electrocution that turns a grounded system (only takes one fault to cause electrocution) to a protected system (takes 2 faults)
What should you do if the line isolation monitor goes off in your room?
Unplug the last item that was plugged in
What is Henry’s Law?
At constant temp, the concentration of gas dissolved is directly proportional to the partial pressure of the gas (concentration is proportional to pressure)
What is Boyle’s Law?
At constant temp, P1V1 = P2V2
What is Gay-Lussac’s Law?
P1/T1 = P2/T2
What is the mechanism of action of digoxin?
Inhibition of Na/K ATPase pump -> sodium comes into cell and potassium leaves cell now -> Na-Ca exchange pump works more, pumping the sodium out for calcium into the cell -> more Ca = more contractility
What problems arise with the use of hetastarches?
- Dilutional reduction of Factor VIII and vWF (50-80%)
- Prolongation of PTT
- Platelet dysfunction
What conditions up-regulate acetylcholine receptors? How does succinylcholine affect these conditions?
MS, ALS, burns, stroke, spinal cord injury, Guillain-Barre syndrome, prolonged immobility, and muscular dystrophies; beware of hyperkalemia with succinylcholine use
What conditions down-regulate acetylcholine receptors? How does succinylcholine affect these conditions?
Myasthenia gravis, anti-cholinesterase poisoning, organophosphate poisoning; MG is resistant to succinylcholine
How much does succinylcholine increase K+ in a healthy patient?
~0.5 mEq/L
What happens if you activate an NMDA receptor?
Non-specific ion channel gets activated, allowing for calcium to enter the cell (increases intracellular calcium)
Where does the supraspinous ligament run from?
C7 to the sacrum
What is the median time to maximum plasma fentanyl concentration with a transdermal fentanyl patch? What is the onset time?
~30 hours until peak; 6-8 hours until onset
What is the null hypothesis? Alternative hypothesis?
Null: there is no difference between the variables in question
Alt: a difference does exist between the variables
What is a type I error? Type II error?
I: Null hypothesis is incorrectly rejected (false positive)
II: Null hypothesis is incorrectly accepted (false negative)
How can you increase power in a study?
- Increase alpha (the smaller the alpha, the greater the chance of a false negative)
- Decrease population variability
- Increase sample size
- Make the difference between the conditions greater
Administration of FFP is not recommended in which of the situations: Hemophilia A, major trauma with blood loss, heparin resistance, TTP
Hemophilia A (would need too much FFP, use factor VIII concentrate or cryoprecipitate)
Why would you use FFP for heparin resistance?
Heparin binds to AT3 and those with heparin resistance have AT3 deficiencies -> thus you give the patient AT3 for heparin to work on
What is the formula for coronary perfusion pressure of the left ventricle?
CPP(LV) = Aortic diastolic pressure - LVEDP
What is the average FRC in an adult?
~30 cc/kg
What type of surgery puts the patient at highest risk of anterior ischemic optic neuropathy? Posterior?
Anterior: cardiac surgery
Posterior: spinal surgery (prone)
What is the formula for the standard error of the mean?
Standard deviation / square root of sample size
During airway manipulation, stimulation of which nerve is responsible for laryngospasm?
Internal branch of the superior laryngeal nerve
