c4. ADVANCED PRInciples B (77-153) Flashcards
78. To achieve a hyperbaric spinal anesthesia, local anesthetic is usually mixed with: A. Dextrose B. CSF C. 0.45% nacl D. Epinephrine
-A. Dextrose
Dextrose is useful for increasing baricity. Easy to sterilize, benign, & does not influence anesthetic
- The most common local anesthetic used in a hyperbaric SAB is:
a. Bupiv
b. Lidocaine
c. Tetracaine
d. Procaine
-c. Tetracaine
Tetracaine & water will have a spec grav slightly less than csf, so that when injected, it will move away from the dependent area
79. All of the following can cause cephalad soread of local anesthetic when given in the sub arachnoid space except: A. Pregnancy B. Advanced age C. Obesity D. Previous spine surgery
-D. Previous psine surgery
The spinal and epidural spaces get smaller with advancing age, obesity & pregnancy; which extends the spread of anesthetic. Spaces become less compliant with age as well.
80. The most cephalad portion of the spinal canal is: A. Third ventricle B. Foramen magnum C. Fourth ventricle D. C1
-B. Foramen magnum
The spinal canal extends from the foramen magnum to the sacral hiatus
81. The spinal cord in the adult ends at: A. L5 B. L3 C. L1 D. L2
-D. L2
The spinal cord extends from the foramen magnum to L2
- Select the false statement about the epidural space:
A. It contains a small amount of free fluid
B. It is filled with adepose
C. It is filled with connective tissue
D. Venous plexuses are prominent
-A. It contains a small amount of free fluid
The epidural space is a “potential space” filled with connective and adipose tissue. Venous plexuses ( batson’s veins) are prominent, but NO FREE FLUID exists in the space.
83. An imaginary line drawn along the back from one iliac crest to the ither would cross cross in the middle at: A. L3 B. L4 C. L3-L4 interspace D. L4-L5 interspace
-B. L4
The line from iliac crest to iliac crest (Touffier’s or crystalline line) usually crosses the fourth lumbar vertebra. The interspace above is L3-L4, and the interspace below the line is L4-L5
- The definitive treatment fopr postdural puncture headache is:
a. caffiene
b. fluids
c. epidural blood patch
d. supine position
-c. epidural blood patch
Conservative treatment is usually indicated within the first 24 hours. However, if treatment is unsuccessful, then an epidural blood patch relieves the headache in 80% of cases if performed after 24 hours
- Stimuli generated from thermal, mechanical , or chemical tussue damage are received from:
a. both A delta and C fibers
b. A fibers only
c. B fibers
d. C fibers only
-a. both A and C fibers
Stimuli generated from thermal, mechanical, or chemical damage activates nocioceptors that are free afferent nerve endings of A delta myelinated & C fibers.
- For carotid endarectomy under regional anesthesia, the nerves that must be blocked are:
a. C1-C4
b. C2-C4
c. C2-C6
d. C1-C3
-b. C2-C4
anesthesia requires sensory blockade of the cervical nerves C2 to C4, which is provided by blockade of the deep cervical plexus
- As a hyperbaric anesthetic solution spreads through the cerebrospinal fluid, a gradient occurs between sympathetic and motor blockade. This is:
a. theoretical but no actual clinical difference
b. motor block two segments above sensory block
c. sensory block equivilent to motor block
d. sympathetic block one to two segments above sensory block
-d. sympathetic block one to two segments above sensory block
A differential block results in:
–sympathetic blockade one to two segments ABOVE the sensory block and
–motor blockade one to two segments BELOW the sensory block.
- All of the following are immediate treatments of total spinal anesthesia except:
a. pressor support
b. reverse trendelenberg position
c. positive pressure ventilation
c. volume infusion
-b. reverse trendelenberg position
The trendelenberg position in an attempt to halt further rise of the block may do more harm than good. The level will not recede in the reverse trendelenberg position and cardiac output will only decrease further.
- Nausea and vomiting after administration of spinal anesthetic is caused by:
a. unopposed sympathetic tone
b. local anesthetic overdose
c. local anesthetic allergy
d. decrease in cerebral blood flow
-d. decreased cerebral blood flow
Nausea and vomiting are common because unopposed vagal tone or hypotension that decreases cerebral blood flow.
- Bradycardia after a spinal anesthetic may occur due to all of the following except:
a. unopposed vagal tone
b. blockade of the cardioaccelerator fibers
c. bezold jarisch reflex
d. all of the above
-d. all of the above
Bradycardia is usually multifactorial and may include vagal tone from high sympathetic blockade of the cardioaccelerator fibers in T1-T5, and the Bezold Jarisch reflex which is the slowing of the heart due to a drop in venous return
- When performing a digital nerve block, all of the following are true except:
a. they are easily performed
b. large volumes can cause a pressure injury
c. vasoconstrictors allow for less anesthetic volume
d. the nerves run along each side of the fingers
-91. c vasoconstrictors allow for less anesthetic volume
Vasoconstrictors are never used in blocks of the fingers, toes, penis, tip of the nose or ears vecause intense vasoconstriction can cause ischemia and necrosis
- The main pathway in the formation of epinephrine begins with:
a. norepinephrine
b. dopamine
c. dopa
d. phenylalanine
- d. synthesis of epi begins with PHENYLALANINE or TYROSINE which:
- converts to dopa…which
- converts to dopamine…which
- converts to norepinephrine… which finally
- converts to epinephrine
- Which of the following drugs exibit dopamine blocking activity as part of its mechanism?
a. ketamine
b. clonidine
c. cimetidine
d. metoclopramide
-d. metoclopramide
Reglan produces its antiemetic effect by blocking dopamine receptors similar to droperidol and produces its gastrokinetic action through cholinergic receptors
- all of the following result after aortic crossclamping except:
a. aerobic metabolism to the lower extremities
b. maximal vasodilation in the lower extremities
c. halted blood flow in the lower extremities
d. decreased renal blood flow with renal corss clamping
-a. aerobic metabolism to the lower extremities
because of the lack of perfusion below the clamp, metabolism switches to anerobic pathways resulting from the lack of oxygen availability
- All of the following can result from infrarenal cross clamping except:
a. acute renal failure
b. acute tubular necrosis
c. increased glomerular filtration rate
d. decreased renal blood flow
-c. increased GFR
as a result of the reduction of renal blood flow, glumerular filtration rate is greatly reduced in cases where infrarenal cross-clamping occurs
- an exaggerated fluctuation of blood pressure during the ventilatory cycle is:
a. pulsus alternans
b. pulsus paradoxus
c. pulse pressure
d. pulse respar
-b. pulsue paradoxus
Pulsus paradoxus refers to a greater than 10 mmhg decline in blood pressure during spontaneous ventilation. It is an early sign of cardiac failure
- Amaurosis fugax is:
a. contralateral to the ischemic side
b. indicative of a large evolving stroke
c. drooping of the eye secondary to optic nerve ischemia
d. transcient monocular blindness
-d. transcient monocular blindness
Small emboli in the opthalmic branches cause transcient monocular blindness known as amaurosis fugax. They may occur during carotid artery surgery.
- The paradoxic effect of hypocapnia producing increased blood flow to ischemic regions of the brain is:
a. inverse steal
b. intracerebral steal
c. luxury perfusion
d. reverse Robin Hood phenomenon
-a. inverse steal syndrome
vasoconstriction is assumed to occur in adjacent normal arterioles, thereby causing a local increase in perfusion pressure and augmenting collateral flow to the abnormal area
- The most common coexisting medical condition in the patient undergoing carotid endarterectomy is:
a. hypertension
b. diabetes
c. CAD
d. renal failure
-a. hypertension
although all of the conditions are possible, hypertension is vary common in patiens with severe carotid artery disease (HTN likely to decrease baroreceptor sensitivity)
- With regard to cerebral blood flow, select the false statement:
a. not all general anesthetics affect cerebral blood flow
b. in general volatile agents are cerebral vasodilators
c. in general, IV anesthetics are cerebral vasoconstrictors
d. ketamine causes vasodilation
-a. not all general anesthetics affect cerebral blood flow
All general anesthetics affect cerebral blood flow to some extent. The potent inhalation agents tend to be cerebral vasodilators, which increase cerebral blood flow and may increase intracranial pressure in a patient with cerebral neuropathy
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