QOD Flashcards
1
Q
Reduction of HR in seen with the administration of opiates is mediated through the
A
Mu Receptors
-The cardiovascular effects of narcotics appear to be mediated through the mu receptors. In addition, these receptors seem, at least in part, to be responsible for the ventilatory depression associated with narcotic admnistration.
2
Q
Effects of 60Hz current on a human for 1 second
A
- Perception Threshold – 1mAMP
- Let Go Current – 15mAMP
- Microshock – 100uAMP
- V.Fib – 200mAMP
3
Q
The mortality after liposuction is most commonly the result of:
- PE
- Bowel Perforation
- Fat Embolism
- Reaction to anesthetic gases
A
Pulmonary Embolism
-Mortality rate is 0.02%. PE accounts for 23.1% of the deaths.
4
Q
Heart rate:
- sole determinant of CO in the elderly
- normally determined by intrinsic rate of AV node
- decreases with increasing age
- increased by stimulation of M2 cholinergic receptor
A
Decreases with increasing age
-Cardiac output is the product of stoke volume and heart rate. Heart rate is an intrinsic function of the SA node and decreases with increasing age. Enhanced vagal activity slows the heart via stimulation of the M2 cholinergic receptors.
5
Q
Pulmonary effects of B-2 adrenergic stimulation include: (select 2)
- inhibition of HPV
- decreased bronchial secretions
- pulmonary vasoconstriction
- bronchodilation
- redirection of blood flow to lower V/Q units
- activation of type II pneumocystis
A
decreased bronchial secretions
bronchodilation
-The tracheobronchial tree receives sympathetic innervation form the T1 - T4 nerve roots. β2 stimulation causes bronchodilation and decreased secretions. The sympathetic nervous system has minimal effects on pulmonary vascular tone. However, α1 stimulation causes some degree of pulmonary vasoconstriction.
6
Q
Nervous system changes seen in the pregnant patient at term include: (Select 2)
- increased minimum alveolar concentration
- increased sensitivity to local anesthetics
- decreased CSF volume
- decreased cephalic spread of spinal anesthetics
- decreased epidural space pressure
- increased potential volume of epidural space
A
- increased sensitivity to local anesthetics
- decreased CSF volume
-Nervous system effects of pregnancy include a decreased MAC, an increased sensitivity to local anesthetics, an increase in epidural blood volume, increased pressure of the epidural space and a decrease in spinal CSF volume. There is an increase in the cephalad spread of both spinal and epidural anesthetics.
7
Q
Clinical signs of a tension pneumothorax include:
- contralateral absence of breath sounds
- ipsilateral hypo resonance to percussion
- neck vein distension
- all of the above
A
- neck vein distension
- A tension pneumothorax develops from air entering the pleural space through a one-way valve in the lung or chest wall. Clinical signs include ipsilateral absence of breath sounds, hyperresonance to percussion, contralateral tracheal shift and distended neck veins.
8
Q
Portal HTN leads to the development of portal-systemic venous collateral channels. These collateral sites commonly include the:
- hemorrhoidal veins
- pulmonary veins
- hepatic veins
- azygous veins
A
- hemorrhoidal veins
- Chronic portal hypertension leads to the development of portal-systemic collateral channels. Four major collateral sites are commonly recognized: gastroesophageal, hemorrhoidal, periumbilical and retroperitoneal.
9
Q
A nonselective a-antagonist used in the preoperative preparation of a pt. with pheochromocytoma is:
- doxazosin
- propranolol
- phenoxybenzamine
- terazosin
A
- phenoxybenzamine
- Phenoxybenzamine is a nonselective α-antagonist used in the preoperative preparation of the patient with pheochromocytoma. Doxazosin and terazosin are selective α1-antagonists. Propranolol is a nonselective β-antagonist. In the preparation of patients with pheochromocytoma, α-blockade and intravascular volume replacement must precede β-blockade, so as to prevent the possibility of unopposed α-stimulation.
10
Q
The portion of the nephron responsible for concentration of urine via the countercurrent mechanism is the:
- glomerulus
- loop of Henle
- proximal convoluted tubule
- distal convoluted tubule
A
- Loop of Henle
- The loop of Henle is responsible for formation of hypertonic fluid in the (renal) medullary interstitium via the countercurrent multiplier system.
11
Q
Postoperative ulnar nerve injury:
- results in wrist drop and loss of sensation in the web space between the thumb and index finger
- occurs more frequently in males
- manifests itself in the immediate postoperative period
- is most commonly seen in the patient with a BMI of less than 38
A
-occurs more frequently in males
-Three attributes which are highly associated with development of postoperative ulnar nerve injury are:
1) male sex - various reports suggest that 70-90% of patients with postoperative ulnar neuropathy are men
2) high body mass index - BMI > or = 38
3) prolonged postoperative bed rest.
Many patients with postoperative ulnar neuropathy have a high frequency of contralateral ulnar nerve dysfunction, suggestive of a pre-existing abnormality. Patients may not develop symptoms of ulnar neuropathy until more than 48 hours postoperatively. Wrist drop and loss of sensation of the web space between the thumb and index finger is associated with radial nerve injury.
12
Q
The Carlens tube is best represented by:
A
-The Carlens double-lumen tubes have a carinal hook to aid in proper placement and minimize tube movement after placement. Potential problems with carinal hooks include increased difficulty with proper placement, trauma to the airway, interference with bronchial closure, and break-off of the hook, which can become lost in the bronchial tree.
13
Q
In contrast to patients undergoing on-pump coronary artery bypass grafting (CABG), patients undergoing off-pump CABG:
- usually require little volume replacement
- do not require anticoagulation
- have isolated left coronary of left anterior descending artery disease
- usually require relatively high mean arterial pressures during distal anastomoses grafting
A
- usually require relatively high mean arterial pressures during distal anastomoses grafting
- Off-pump CABG (OPCAB) is done in patients with a variety of coronary artery lesions. Since the patient will not be receiving the volume of the pump-prime, crystalloid and/or colloid solutions are used to correct fluid deficit. Anticoagulation is required, but partial heparinization is often used. During distal anastomoses grafting, CPP is maintained by keeping a relatively high MAP.
14
Q
The single greatest cause of mortality in the patient with sickle cell disease is a result of:
- acute chest syndrome
- sequestration crisis
- aplastic crisis
- vaso-occlusive crisis
A
- acute chest syndrome
- ACS represents the single greatest threat to the patient with SCD as the mortality is 1% to 20%. The diagnosis of ACS can be made when there are new lung infiltrates on a chest radiograph in the presence of any of the following: chest pain, cough, dyspnea, wheezing, or hypoxemia. Proposed mechanisms of ACS are thrombosis, embolism (clot and fat), and infection. The frequency of ACS after abdominal surgery is 10% to 20%.
15
Q
The line isolation monitor:
- provides a source of ungrounded electrical power
- reduces the risk microshock
- monitors the integrity of the isolated power system
- monitors the integrity of equipment grounding wires
A
- monitors the integrity of the isolated power system
- The line isolation monitor continuously monitors the integrity of the isolated power system. The line isolation transformer provides ground isolation. Microshock hazards occur with the delivery of 100 microamps or less of current directly to the endocardium. These small amounts of current are well below the sensing range of the ground isolation monitor. The LIM is unable to detect a faulty grounding connection in the equipment attached to the circuit.
16
Q
Parasympathetic preganglionic fibers are found in: (Select 3)
- cranial nerve IV
- cranial nerve VII
- cranial nerve IX
- cranial nerve XI
- thoracic nerve 9
- thoracic nerve 11
- sacral nerve 1
- sacral nerve 2
A
- cranial nerve VII, cranial nerve IX, sacral nerve 2
- Parasympathetic preganglionic fibers are found in cranial nerves III, VII, IX and X as well as sacral nerves 2, 3 and 4.
17
Q
Electrolyte containing irrigation solutions are avoided during transurethral resection of the prostate because they:
- interfere with the use of the cautery
- can precipitate severe hyponatremia
- can cause hyperglycemia in diabetic patients
- are associated with elevated ammonia levels postoperatively
A
- interfere with the use of the cautery
- Electrolyte containing solutions conduct electricity and interfere with cautery use during the resection of the prostate. Electrolyte solutions are commonly used in the postop period. Sorbitol solutions have been associated with hyperglycemia, especially in diabetic patients. Glycine solutions have been associated with elevated ammonia levels and transient postoperative visual syndrome. Sorbitol, glycine and distilled water have all been associated with TURP syndrome.
18
Q
The use of nonionic gadolinium contrast media during MRI:
- can result in ionizing radiation exposure to the patient & anesthesia provider
- results in frequent allergic reactions, urticaria & bronchospasm
- is commonly associated with nausea
- should be avoided in patients with a pacemaker or AICD
A
- is commonly associated with nausea
- Gadolinium contrast for MRI is not a source of ionizing radiation. The incidence of allergic reactions to MRI contrast is extremely low, especially as compared to conventional radiographic iodine-containing contrasts. Nausea is a common side effect of MRI contrast administration. Although caution must be used in patients undergoing MRI with ferromagnetic implants, which may include both pacemakers and AICDs, the administration of MRI contrast is not contraindicated.
19
Q
The speed in an inhalation induction is slowed by right-to-left shunting. The change in the rate of induction is LEAST pronounced when using:
- nitrous oxide
- sevoflurane
- desflurane
- isoflurane
A
- isoflurane
- With right-to-left shunting there is slowing of an inhalation induction. This effect is less pronounced with agents with high blood/gas solubilities.
20
Q
MAC-BAR is the:
- partial pressure of an anesthetic required to abolish movement in 50% of patients
- partial pressure of an anesthetic at which subjects will open their eyes
- partial pressure of an anesthetic at which autonomic blockade occurs
- partial pressure of an anesthetic at which amnesia occurs
A
- partial pressure of an anesthetic at which autonomic blockade occurs
- MAC-BAR is the minimum alveolar concentration that blocks autonomic reflexes. MAC-BAR is considerably greater than MAC, particularly in the absence of opioids. It has been estimated that MAC-BAR is approximately 50% above standard MAC.
21
Q
In a 6-year-old, the appropriate length of an endotracheal tube from distal tip to incisors is:
- how many cm?
A
- 15-16.5cm
- Several formulas exist to estimate the length of ETT insertion in patients aged 2 to 12 years. One of the most frequently used is:
Age/2 +12
22
Q
Local anesthetic solutions that are isobaric with the cerebrospinal fluid include: (Select 2)
- tetracaine 0.5% in 5% dextrose
- bupivacaine 0.75% in normal saline
- procaine 10% in sterile water
- lidocaine 2% in normal saline
- bupivacaine 0.3% in sterile water
- lidocaine 5% in 7.5% dextrose
A
- Bupivicaine 0.75% in NS
- Lidocaine 2% in NS
-Hyperbaric Tetracaine: 0.5% in 5% dextrose Bupivacaine: 0.75% in 8.25% dextrose Lidocaine: 5% in 7.5% dextrose Procaine: 10% in water
-Isobaric Tetracaine: 0.5% in caline Bupivacaine: 0.75% in saline Bupivacaine: 0.5% in saline Lidocaine: 2% in saline
-Hypobaric
Tetracaine: 0.2% in water
Bupicacaine: 0.3 in water
Lidocaine: 0.5% in water
23
Q
An 82-year-old female arrives to the OR for open reduction of a left intratrochanteric fracture. Significant past medical history includes hypertension, moderate aortic stenosis and dementia. The most appropriate anesthetic technique for this patient is:
- opioid-based general anesthesia
- spinal anesthesia
- volatile-agent-based general anesthesia
- epidural anesthesia
A
- opioid-based general anesthesia
- In patients with mild to moderate aortic stenosis, a primarily opioid-based technique results in minimal cardiac depression, less tachycardia and suppression of the sympathetic response to surgical stimulation. These are all desired effects as HTN and tachycardia may precipitate ischemia in these patients. Spinal or epidural anesthesia as well as a volatile-agent-based anesthesia can cause a fall in afterload with resulting severe hypotension.
24
Q
What is the pharmacologic mechanism of action of the anticoagulants below? Please match medications with MOA:
- Anti-thrombin activation
- Vit. K Inhibition
- Thrombin Inhibition
- Factor Xa Inhibition
- Warfarin
- Hirudin
- Heparin
- Rivaroxaban
A
- Anti-thrombin activations – Heparin
- Vit. K Inhibition – Warfarin
- Thrombin Inhibition – Hirudin
- Factor Xa Inhibition – Rivaroxaban
25
The rate of seroconversion after exposure of mucous membranes to HIV-infected blood is approximately:
- 0.03%
- 0.09%
- 0.3%
- 0.9%
- 0.3%
- Percutaneous exposure (needle stick) carries a risk of HIV-seroconversion of approximately 0.3% or about 1:300. Mucous membrane exposure carries a risk of approximately 0.09% or about 1:1100.
26
Actuation of the oxygen flush valve delivers 100% oxygen at a rate of:
- 10 - 20 L/min
- 20 - 30 L/min
- 35 - 75 L/min
- 80 - 100 L/min
- 35-75 L/min
| - The oxygen flush valve delivers 100% oxygen at a rate of 35 - 75 L/min with a pressure of 40 - 60 psi.
27
A decrease in cholinesterase activity has been associated with:
- obesity
- thyrotoxicosis
- alcoholism
- burns
- burns
- Burns, liver disease, 3rd trimester of pregnancy, carcinoma, renal failure and collagen diseases as well as certain drug therapy have been associated with a decrease in cholinesterase activity. Increased cholinesterase activity has been associated with obesity, alcoholism, thyrotoxicosis, nephrosis, psoriasis and electro-convulsive therapy.
28
The incidence of headache with inadvertent dural puncture during epidural anesthesia is decreased:
- with decreasing age
- by keeping the patient supine for more than 12 hours following puncture
- with the use of fluid, instead of air, for loss of resistance
- by inserting the needle with the bevel aligned perpendicular to the long axis of the meninges
- with the use of fluid, instead of air, for loss of resistance
- The use of fluid instead of air has been associated with a significant reduction in the incidence of postdural puncture headache (PDPH). Other factors associated with a reduced incidence of PDPH are: increasing age, insertion of the bevel aligned parallel to the long axis of the meninges and the use of smaller needles. There is no evidence that keeping the patient supine reduces the incidence of PDPH.
29
Factors decreasing physiologic dead space include:
- the supine position
- anticholinergic agents
- increasing age
- emphysema
- supine position
- Dead space is comprised of gases in non-respiratory airways (anatomic dead space) as well as in alveoli that are not perfused (alveolar dead space). The sum of the two is known as physiologic dead space. Certain factors affect dead space. The supine position is known to decrease dead space, whereas anticholinergics, β2-sympathomimetics, advancing age and COPD all increase dead space.
30
The most consistent clinical manifestation of aspiration pneumonitis is:
- bronchospasm
- arterial hypoxemia
- pulmonary vasoconstriction
- tachypnea
- arterial hypoxemia
- Inhaled gastric fluid is rapidly distributed throughout the lungs, leading to destruction of surfactant-producing cells, damage to the pulmonary capillary endothelium and resultant atelectasis and pulmonary edema. Arterial hypoxemia is the most consistent clinical finding associated with aspiration pneumonitis. Tachypnea, bronchospasm and pulmonary vasoconstriction with secondary pulmonary hypertension may also be present.
31
A full-term, 4.2 kg neonate is scheduled for a thoracotomy for resection of congenital lobar emphysema. The infant's starting hematocrit is 48%. Estimated allowable blood loss to maintain a hematocrit at or above 38% is:
-___ cc?
-70-110cc
-The full-term neonate has approximately 85 ml/kg total blood volume. Therefore:
4.2 kg x 85 ml/kg = 357 ml (blood volume)
MABL = Blood Volume x (HCT(starting) - HCT(final)) / HCT(average)
357 ml x (48 - 38) / 43 = 83 mL
32
Hormones released by the neurohypophysis include: (Select 2)
- thryotropin
- growth hormone
- arginine vasopressin
- adrenocorticotropic hormone
- follicle stimulating hormone
- oxytocin
- prolactin
- luteinizing hormone
- arginine vasopressin
- oxytocin
-The neurohypophysis is another term for the posterior pituitary gland. The hormones of the neurohypophysis, oxytocin and arginine vasopressin (vasopressin, ADH), are synthesized in the hypothalamus and stored in the posterior pituitary. Stimulus for the release of arginine vasopressin arises from osmoreceptors in the hypothalamus that sense an increase in plasma osmolality.
33
Pancreatic somatostatin producing cells in the Islets of Langerhans are:
- alpha cells
- beta cells
- gamma cells
- delta cells
- delta cells
- The Islets of Langerhans are comprised of four cell types: alpha cells producing glucagon, beta cells producing insulin, delta cells producing somatostatin and PP cells producing pancreatic polypeptide.
34
Causes of normal-anion-gap acidosis include:
- renal failure
- starvation
- diarrhea
- lactic acidosis
- diarrhea
- Normal-anion-gap acidosis is also called hyperchloremic acidosis and results from the selective loss of bicarbonate anion or the introduction of large amounts of chloride anion. Common causes include: diarrhea, hypoaldosteronism, renal tubular acidosis and increased intake of chloride containing acids sometimes found in hyperalimentation.
35
Carbonic anhydrase inhibitors are used in the treatment of:
- acute glaucoma
- renal tubular acidosis
- diarrhea induced acidosis
- acidosis resulting from hypoventilation
- acute glaucoma
- Carbonic anhydrase inhibitors decrease the ability of the kidneys to reabsorb bicarbonate, resulting a hyperchloremic acidosis. As a result, carbonic anhydrase inhibitors would be avoided in patients with acidosis, especially a normal-anionic-gap acidosis. Because bicarbonate is filtered by the ciliary process in the formation of aqueous humor, carbonic anhydrase inhibitors reduce the formation of aqueous humor and can be used to decrease intraocular pressure.
36
Hypoxemia during one-lung anesthesia is most effectively treated by:
- PEEP applied to the ventilated lung
- continuous oxygen insufflation to the collapsed lung
- changing tidal volume and rate
- periodic inflation of the collapsed lung
- periodic inflation of the collapsed lung
- The application of PEEP to the ventilated lung, changes in the ventilatory parameters and oxygen insufflation to the collapsed lung may offer marginal improvement in oxygenation. However, periodic inflation of the collapsed lung with oxygen, early ligation of the ipsilateral pulmonary artery and CPAP to the collapsed lung offer consistently effective improvement in oxygenation.
37
Branches of the femoral nerve anesthetized during an ankle block include the:
- deep peroneal nerve
- sural nerve
- saphenous nerve
- posterior tibial nerve
- saphenous nerve
- The saphenous nerve is the only branch of the femoral nerve innervating the foot. The four remaining nerves innervating the foot, the deep peroneal nerve, the posterior tibial nerve, the sural nerve and the superficial peroneal nerve, are all branches of the sciatic nerve.
38
A decrease in pseudocholinesterase activity has been associated with the use of: (Select 3)
- pancuronium
- esmolol
- droperidol
- vecuronium
- metoclopramide
- magnesium sulfate
- dantrolene
- rocuronium
- pancuronium
- metoclopramide
- esmolol
-The following drugs have been associated with a decrease in pseudocholinesterase activity: echothiophate, pyridostigmine, neostigmine, phenelzine, cyclophosphamide, metoclopramide, esmolol, pancuronium and oral contraceptives. Although both dantrolene and magnesium may alter the effects of neuromuscular blockers, neither causes inhibition of pseudocholinesterase.
39
During the delivery of an anesthetic in the radiology department, full E-cylinders of nitrous oxide and oxygen are being used. If a 3 L/min:2 L/min mixture of nitrous oxide:oxygen is being delivered and the case has been proceeding for 60 minutes, the expected pressure in the nitrous oxide E-cylinder is:
- ___ psig?
- 745-750psi
- Nitrous oxide has a critical temperature of 37oC. This allows nitrous oxide to exist as a liquid at room temperature. Full E-cylinders of nitrous oxide contain approximately 1590 L at a pressure of 745 psig. A sixty minute delivery of 3 L/min would result in a 180 L consumption, and this would be inadequate to consume all the liquid nitrous oxide in the tank. As a result, there would be no change in tank pressure.
40
The formation of metanephrine is the result of:
- catechol-O-methyltransferase metabolism of epinephrine
- catechol-O-methyltransferase metabolism of norepinephrine
- monamine oxidase metabolism of epinephrine
- monamine oxidase metabolism of norepinephrine
- catechol-O-methyltransferase metabolism of epinephrine
- Catechol-O-methyltransferase (COMT) metabolizes epinephrine to metanephrine and norepinephrine to normetanephrine. Subsequently, monamine oxidase (MAO) further metabolizes metanephrine and normetanephrine to vanillymandelic acid (VMA).
41
An action potential characterized by a spike followed by a plateau phase is seen in:
- peripheral sensory nerve cells
- peripheral motor nerve cells
- striated skeletal muscle cells
- cardiac muscle cells
- cardiac muscle cell
- In contrast to the action potentials of nerve and skeletal muscle cells, the action potential of the cardiac myocyte is characterized by a sharp spike followed by a plateau phase (2), which results from the opening of slower calcium channels.
42
Interpleural analgesia can be accomplished by placing local anesthetic:
- along the cephalad border of the T6 rib
- immediately deep to the parietal pleura
- immediately deep to the visceral pleura
- superficial to the internal intercostal muscle
- immediately deep to the parietal pleura
- Interpleural analgesia is accomplished by placing an catheter between the parietal and visceral pleura. A loss-of-resistance technique is most commonly used at the T6 to T8 intercostal spaces, or the catheter can be placed under direct vision by the surgeon. Pneumothorax is a significant complication if the needle or catheter penetrates the visceral pleura.
43
The primary causative factor in the development of persistent pulmonary hypertension (PPH) in the neonate is:
- cystic fibrosis
- pregnancy-induced hypertension
- hypoxemia
- right-to-left shunting through a patent ductus arteriosus
- hypoxemia
- Hypoxia or acidosis during the early neonatal period may predispose the infant to return to fetal circulation. This serious condition, previously known as persistent fetal circulation (PFC), is currently known as persistent pulmonary hypertension (PPH). Hypoxemia and/or acidosis promotes an increase in pulmonary vascular resistance which ultimately causes right to left shunting through the ductus arteriosus, foramen ovale, or both. Shunting causes continued hypoxemia, leading to a continued increase in pulmonary vascular resistance, and a vicious cycle ensues. Primary causes of hypoxemia in the neonate include pneumonia and meconium aspiration.
44
Deleterious effects of hypothermia include: (Select 2)
- impaired renal function
- right shift of the hemoglobin-oxygen saturation curve
- irreversible platelet dysfunction
- increased incidence of wound infection
- increased postoperative protein anabolism
- impaired renal function
- increased incidence of wound infection
-Deleterious effects of hypothermia include:
```
increased PVR
left shift of the hemoglobin-oxygen saturation curve
reversible platelet dysfunction
postoperative protein catabolism
altered mental status
impaired renal function
decreased drug metabolism
poor wound healing
increased incidence of infection
cardiac arrhythmias
```
45
Prior to pneumonectomy, split lung function testing is indicated in the patient with:
- an FEV1 of 2.2 L
- a PaCO2 of 49 mm Hg on room air
- a PaO2 of 54 mm Hg on room air
- a maximum VO2 of 21 mL/kg/min
- a PaCO2 of 49mmHg on room air
- Split lung function testing is indicated in patients requiring pneumonectomy, but not meeting the recommended laboratory criteria. Current recommendations for patients requiring pneumonectomy are:
```
PaCO2 < 45 mm Hg
FEV1 > 2 L
Predicted postop FEV1 > 800 mL
Maximum VO2 > 15 mL/kg/min
FEV1/FVC > 50% of predicted
```
46
Closing capacity is defined as:
- closing volume + expiratory reserve volume
- functional residual capacity - residual volume
- closing volume + residual volume
- residual volume + expiratory reserve volume
- closing volume + residual volume
- Closing capacity is the lung volume at which airways begin to close and is defined as the closing volume + residual volume.
47
The elimination half-time of a drug:
- is inversely proportional to the clearance
- is inversely proportional to the volume of distribution
- is directly proportional to clearance
- is shortest in drugs that are rapidly redistributed
- is inversely proportional to the clearance
- The elimination half-timeof a drug is proportional to the volume of distribution and inversely proportional to the rate of clearance.
48
Release of aldosterone by the adrenal cortex is stimulated by: (select 3)
- angiotensin I
- angiotensin II
- hypokalemia
- pituitary ACTH
- congestive heart failure
- hypervolemia
- angiotensin II
- pituitary ACTH
- CHF
-Aldosterone release is stimulated by the renin-angiotensin system, but specifically by angiotensin II. Other causes of aldosterone release include hyperkalemia, ACTH release, hypovolemia, hypotension, CHF and the stress response.
49
Renal blood flow: (Select 2)
- is largely determined by renal oxygen consumption
- accounts for 20 - 25% of the cardiac output
- is distributed mostly to juxtamedullary nephrons
- can be directed away from cortical nephrons by sympathetic stimulation
- is not autoregulated
- accounts or 20-25% of CO
- can be directed away from cortical nephrons by sympathetic stimulation
-The kidneys are the only organ for which oxygen consumption is determined by blood flow; the reverse is true in other organs. The kidneys receive 20 - 25% of the cardiac output with only 10 - 15% going to the juxtamedullary nephrons and 80% going to cortical nephrons. However, blood flow can be redirected to juxtamedullary nephrons by increased levels of catecholamines and angiotensin II. Autoregulation of RBF occurs between mean arterial pressures of 80 - 180 mm Hg.
50
A 36-year-old female is scheduled for an elective cholecystectomy. Her past medical history is significant for depression treated with phenelzine (Nardil). Her anesthetic plan should include: (Select 2)
- discontinuation of phenelzine for at least 2 weeks prior to surgery
- the avoidance of indirect acting vasopressors
- the avoidance of propofol
- the avoidance of meperidine
- the avoidance of nitrous oxide
- the avoidance of volatile anesthetic agents
- avoidance of indirect acting vasopressors
- avoidance of meperidine
-Phenelzine is a monamine oxidase (MAO) inhibitor. The practice of discontinuing MAO inhibitors prior to surgery is no longer recommended. The use of meperidine in patients receiving MAO inhibitors has been associated with hypertensive crisis and should be avoided. Additionally, indirect acting vasopressors have also been associated with hypertensive crisis and direct acting vasopressors should be used to treat hypotension.
51
The most common complication of thoracic paravertebral nerve block is:
- hypotension
- subarachnoid injection
- pneumothorax
- intravascular injection
- pneumothorax
- Pneumothorax is the most common complication of paravertebral block and a chest radiograph is needed upon completion of the block. Other complications include subarachnoid injection, epidural injection, intravascular injection, and hypotension.
52
In the diagram below, regional anesthesia of the area depicted by #1 can be accomplished with a block of the:
- radial nerve
- median nerve
- ulnar nerve
- coracobrachialis nerve
- median nerve
- The median nerve supplies innervation the the area marked as #1, the ulnar nerve to area #3 and the radial nerve to area #2.
53
The largest fraction of carbon dioxide in the blood is in the form of:
- carbamino compounds
- bicarbonate
- dissolved gas
- carboxyhemoglobin
- bicarbonate
| - Nearly 90% of carbon dioxide in the blood is in the form of bicarbonate.
54
A 42-year-old man is undergoing a thoracoscopy. During the procedure an 8-minute period of apneic oxygenation is required. If the patient's PaCO2 is 40 mm Hg, the expected PaCO2 at the end of the apneic period would be:
___ mmHg?
- 67-74mmHg
- The apneic oxygenation technique affords adequate oxygen delivery, but progressive respiratory acidosis limits the use of this technique to 10 - 20 minutes in most patients. Arterial PaCO2 rises 6 mm Hg in the first minute followed by a rise of 3 - 4 mm Hg during each subsequent minute. In this patient this will produce a 27 - 34 mm Hg increase, resulting in a PaCO2 of 67 to 74 mm Hg.
55
The essential component of cardioplegia solutions is:
- mannitol
- magnesium
- potassium
- corticosteroid
- potassium
- High concentrations of potassium (20 - 30 mEq/L) are used in cardioplegia solutions. These solutions result in an increase in extracellular potassium and reduce transmembrane potential. This progressively interferes with the normal sodium currents of depolarization and eventually the sodium channels are completely inactivated.
56
Forms of mechanical ventilation that produce tidal volumes at or below anatomic dead space include: (Select 2)
- high-frequency oscillation
- inverse I:E ratio ventilation
- airway pressure release ventilation
- differential lung ventilation
- high-frequency positive-pressure ventilation
- pressure support ventilation
- high-frequency oscillation
- high-frequency PPV
-High-frequency oscillation (HFO) creates a to-and-fro gas movement in the airway at rates of 400 - 2400 times/min. High frequency positive-pressure ventilation is delivered at a rate of 60 - 120 breaths/min. Tidal volume is at or below anatomic dead space. High-frequency ventilation techniques may be useful in cases of bronchopleural and tracheoesophageal fistulas.
57
During an anterior-posterior spinal fusion, in a 70-kg patient, the laboratory reports an intraoperative hematocrit of 21% with a hemoglobin of 7g/dL. Two units of packed red blood cells are administered over the course of 30 minutes. Upon completion of the transfusion, the anticipated hematocrit will be approximately:
__?
- 25 - 27%
- A commonly used rule of thumb states that each unit of PRBCs increases the hemoglobin 1 g/dL and the hematocrit 2% to 3%.
58
Changes found in banked blood include: (Select 2)
- increased levels of 2,3-DPG
- a left shift of the hemoglobin dissociation curve
- decreased levels of potassium
- formation of microaggregates
- alkalosis secondary to the presence of citrate
- increased intracellular ATP stores
- thrombocytosis
- left shift of the hemoglobin dissociation curve
- formation of microaggregates
-Changes occurring in banked blood include:
```
Depletion of 2,3-DPG
Depletion of intracellular ATP
Oxidative damage
Increased adhesion to vascular endothelium
Altered cell morphology
Accumulation of microaggregates
Hyperkalemia (as high as 17.2 mEq/L)
Absence of platelets (after 2 days of storage)
Hemolysis
Accumulation of proinflammatory products
```
59
A nonselective α-antagonist used in the preoperative preparation of a patient with pheochromocytoma is:
- phenoxybenzamine
- doxazosin
- propranolol
- terazosin
- phenoxybenzamine
- Phenoxybenzamine is a nonselective α-antagonist used in the preoperative preparation of the patient with pheochromocytoma. Doxazosin and terazosin are selective α1-antagonists. Propranolol is a nonselective β-antagonist. In the preparation of patients with pheochromocytoma, α-blockade and intravascular volume replacement must precede β-blockade, so as to prevent the possibility of unopposed α-stimulation.
60
Average blood loss during a vaginal delivery is
- 100 - 200 ml
- 400 - 500 ml
- 700 - 800 ml
- 1000 - 1500 ml
- 400-500 cc
- At term, blood volume has increased by 1000 - 1500 ml in most women allowing them to easily tolerate the blood loss associated with delivery. Average blood loss during vaginal delivery is 400 - 500 ml, compared with 800 - 1000 ml for cesarean section.
61
Physiologic derangements seen in the patient with scleroderma include: (Select 3)
- pulmonary hypertension
- esophageal dysmotility
- excessive oral secretions and salivation
- myocardial fibrosis
- hypotension
- spastic quadraparesis
- pulmonary HTN
- esophageal dysmotility
- myocardial fibrosis
-Scleroderma is an autoimmune disease with multi-organ involvement. It is characterized by excessive deposition of collagen and subsequent fibrosis of the skin and internal organs. Manifestations are most evident in the skin, but pulmonary, cardiac, vascular and renal involvement may also be present. Patients with scleroderma are frequently difficult intubations and are at high risk for aspiration. Systemic hypertension from renal disease is very common. Xerostomia and decreased lacrimation are a result of exocrine gland involvement.
62
Bone marrow depression and peripheral neuropathy have been associated with prolonged exposure to anesthetic concentrations of:
- isoflurane
- desflurane
- sevoflurane
- nitrous oxide
- nitrous oxide
- By irreversibly oxidizing the cobalt atom in vitamin B12, nitrous oxide inhibits vitamin B12 dependent enzymes. These enzymes include methionine synthetase and thymidylate synthetase. As a result of these enzyme inhibitions, prolonged exposure to nitrous oxide has been associated with bone marrow depression, megaloblastic anemia, peripheral neuropathy and teratogenicity.
63
An increase in the plasma concentration and a prolongation of the elimination half-life of etomidate is seen with the concomitant administration of:
- midazolam
- rocuronium
- fentanyl
- succinylcholine
- fentanyl
- Fentanyl has been shown to increase the plasma level of etomidate as well as prolong the elimination half-life of the drug.
64
During emergent transtracheal jet ventilation using a 14 gauge catheter, generation of sufficient gas flow requires a driving pressure of:
- 20 cmH2O
- 50 cmH2O
- 25 psi
- 50 psi
- 50 psi
- After proper location of the catheter is confirmed by aspiration air, jet ventilation may be achieved with intermittent pulses of oxygen at 50 psi.
65
Sensory innervation of the trachea and larynx below the vocal cords is supplied by the:
- internal laryngeal nerve
- external laryngeal nerve
- recurrent laryngeal nerve
- glossopharyngeal nerve
- recurrent laryngeal nerve
- The vagus nerve provides sensation to the airway below the epiglottis. The superior laryngeal branch of the vagus divides into an external (motor) and internal (sensory) laryngeal nerve that provide sensory supply to the larynx between the epiglottis and the vocal cords. Another branch of the vagus, the recurrent laryngeal nerve, innervates the larynx below the vocal cords and trachea.
66
Correct statements concerning the use of benzodiazepines in the elderly include:
- volume of distribution is increased
- reduced pharmacodynamic sensitivity is observed
- the elimination half-life of diazepam, but not midazolam, is increased
- all of the above
- volume of distribution is increased
- Aging increases the volume of distribution for all benzodiazepines, effectively prolonging their elimination half-times. Enhanced pharmacodynamic sensitivity is also observed. The elimination half-times of both diazepam and midazolam are increased.
67
Concerning preoperative informed consent:
- it should disclose only life-threatening complications
- charges of assault and battery are possible if it is not obtained
- oral consent is insufficient
- it is not necessary if the procedure is done in an office setting
- charges of assault and battery are possible if it is not obtained
- Any procedure performed without the patient's consent can constitute assault and battery. Oral consent may be sufficient, but written consent is advisable for medicolegal purposes. It is generally accepted that not all risks need to be detailed, but risks that are realistic and have resulted in complications in similar patients should be disclosed.
68
The National Institute for Occupational Safety (NIOSH) recommends limiting the operating room concentration of nitrous oxide to:
- 0.5 ppm
- 5 ppm
- 25 ppm
- 50 ppm
- 25 ppm
- NIOSH recommends limiting the room concentration of nitrous oxide to 25 ppm and halogenated agents to 2 ppm (0.5 ppm if nitrous oxide is also being used).
69
The highest incidence of muscle pain following the use of succinylcholine is seen in:
- infants
- octogenarians
- outpatients
- pregnant patients
- outpatients
- Myalgia following the use of succinylcholine is most commonly seen in females and outpatients. Pregnancy and extremes of age seem to be protective.
70
Anesthetic implications of multiple sclerosis include:
- the postponement of elective procedures during relapse
- exacerbation induced by peripheral nerve block
- exacerbation of symptoms secondary to hypothermia
- the presence of significant peripheral neuropathy causing severe hyperkalemia after succinylcholine administration
- postponement of elective procedures during relapse
- Surgery and other physiologically stressful events should be avoided during episodes of relapse. Epidural and other regional techniques appear to have no adverse effect, especially in obstetrics; however a lower concentration of local anesthetic should be used. Demyelinated nerve fibers are extremely sensitive to hyperthermia, but conduction is usually improved by mild hypothermia.
71
Local anesthetics with the potential to form methemoglobin include: (Select 3)
- EMLA topical anesthetic cream
- bupivacaine
- benzocaine
- ropivacaine
- prilocaine
- mepivacaine
- EMLA topical anesthetic cream
- benzocaine
- prilocaine
-EMLA cream contains both lidocaine and prilocaine. The metabolites of prilocaine can convert hemoglobin to methemoglobin. Benzocaine can also cause methemoglobinemia.
72
Ulnar nerve injury:
- results in wrist drop and loss of sensation in the web space between the thumb and index finger
- occurs more frequently in males
- manifests itself in the immediate postoperative period
- is most commonly seen in the patient with a BMI of less than 18
-occurs more frequently in males
-Three attributes which are highly associated with development of postoperative ulnar nerve injury are:
1) male sex - various reports suggest that 70 - 90% of patients with postoperative ulnar neuropathy are men
2) high body mass index - BMI > or = 38
3) prolonged postoperative bed rest.
Many patients with postoperative ulnar neuropathy have a high frequency of contralateral ulnar nerve dysfunction, suggestive of a pre-existing abnormality. Patients may not develop symptoms of ulnar neuropathy until more than 48 hours postoperatively. Wrist drop and loss of sensation of the web space between the thumb and index finger are associated with radial nerve injury.
73
The potency of local anesthetics increases as the:
- lipid solubility increases
- pKa increases
- number of double bonds in the anesthetic molecule increases
- molecular weight decreases
- lipid solubility increases
- Local anesthetic potency correlates directly with lipid solubility. In general, lipid solubility increases with an increase in the total number of carbon atoms in the molecule and by adding a halogen to the aromatic ring.
74
A decrease in cerebral blood flow is seen after the administration of:
- isoflurane
- propofol
- desflurane
- ketamine
- propofol
- The inhaled anesthetic agents and ketamine all increase cerebral blood flow (CBF). Benzodiazepines, etomidate, propofol and barbiturates all decrease CBF.
75
During surgical repair of a detached retina, 1 mL of sulfur hexafluoride is injected into the posterior chamber. If the patient is receiving 4% desflurane and a 2:1 ratio of N2O and O2, the pressure-volume relationship of the bubble will approximately:
- decrease by one third
- remain the same
- double
- triple
- triple
- A sulfur hexafluoride gas bubble is sometimes used to support the retina after detachment. Diffusion of nitrous oxide into the bubble will cause expansion as nitrous oxide equilibrates with the gas bubble. A sixty-seven percent nitrous oxide concentration will cause the bubble to triple in its pressure-volume relationship in about 30 minutes and may double the intraocular pressure (IOP). In addition, when nitrous oxide is discontinued, the bubble will return to normal size, causing a fall in IOP and possible extension of the retinal tear. For these reasons, it is recommended that nitrous oxide be discontinued at least 15 minutes prior to the injection of a posterior chamber bubble.
76
Topically applied ophthalmic medications are absorbed:
- as quickly as intravenous administration
- more quickly than subcutaneous administration
- only minutely, with insignificant clinical effect
- directly into the central nervous system through the optic nerve foramen
- more quickly than subcutaneous administration
- Topically applied ophthalmic medications are absorbed at a rate intermediate between intravenous and subcutaneous injection. Children and the elderly are at particular risk for the toxic effects of topically applied medications.
77
During pregnancy, the minimum alveolar concentration (MAC):
- decreases until the 20th week
- increases until the 20th week
- decreases throughout the pregnancy
- increases throughout the pregnancy
- decreases throughout the pregnancy
- The MAC progressively decreases during pregnancy, at term by as much as 40%. MAC returns to normal by the third day after delivery.
78
The arteria radicularis magna, or artery of Adamkiewicz, most commonly arises from:
- T4 - T8
- T8 - L2
- L2 - L4
- L4 - S1
- T8-L2
- A major complication of thoracic aortic surgery is paraplegia, occurring in up to 20% of elective cases, and is secondary to spinal cord ischemia. The arteria radicularis magna supplies blood to the anterior spinal artery. The arteria radicularis magna has a variable origin from aorta, arising between T5 - T8 in 15%, between T9 - T12 in 60% and between L1 - L2 in 25% of individuals.
79
The most severe transfusion reactions are due to:
- ABO incompatibility
- Rh incompatibility
- febrile reactions
- non-ABO hemolytic reactions
- ABO incompatibility
- The most severe transfusion reactions are due to ABO incompatibility. Naturally acquired antibodies can react against the transfused antigens, activate complement and result in intravascular hemolysis.
80
Intracranial hypertension is defined as a sustained increase in intracranial pressure (ICP) above:
- 5 mm Hg
- 15 mm Hg
- 25 mm Hg
- 30 mm Hg
- 15 mmHg
- Intracranial hypertension is defined as a sustained increase in intracranial pressure (ICP) above 15 mm Hg. Uncompensated increases in tissue or fluid within the rigid intracranial vault produce the sustained pressure elevations.
81
Cholinesterase inhibitors that freely cross the blood-brain barrier include:
- neostigmine
- pyridostigmine
- physostigmine
- edrophonium
- physostigmine
- Physostigmine is a teritary amine and has a carbamate group, but no quaternary ammonium. Therefore, it is lipid soluble and is the only clinically available cholinesterase inhibitor that freely passes the blood-brain barrier.
82
In patients receiving vecuronium, the greatest augmentation of neuromuscular blockade is seen with the use of:
- isoflurane
- sevoflurane
- desflurane
- nitrous oxide
- desflurane
- Volatile agents decrease the nondepolarizer dosage requirements. The degree of the augmentation of blockade depends on the inhalational agent, with desflurane > sevoflurane > isoflurane > nitrous oxide.
83
The highest rate of systemic absorption of local anesthetic is seen with:
- epidural injection
- intercostal injection
- caudal injection
- brachial plexus injection
- intercostal injection
- The rate of systemic absorption of local anesthetic is proportionate to the vascularity of the site of injection: intravenous > tracheal > intercostal > caudal > paracervical > epidural > brachial plexus > subcutaneous.
84
Selective adrenergic stimulation of the β2-receptor results in:
- increased heart rate
- increased insulin secretion
- detrusor muscle contraction
- pupillary constriction
- increased insulin secretion
- β2-receptor stimulation results in: increased insulin secretion, bronchodilation, increased salivary gland secretion, decreased upper GI motility, gluconeogenesis, pupillary dilation and detrusor muscle relaxation. Increased heart rate is a result of β1-receptor stimulation. Pupillary constriction (miosis) is the result of parasympathetic stimulation.
85
Pancreatic somatostatin producing cells in the Islets of Langerhans are:
- alpha cells
- beta cells
- gamma cells
- delta cells
- delta cells
- The Islets of Langerhans are comprised of four cell types: alpha cells producing glucagon, beta cells producing insulin, delta cells producing somatostatin and PP cells producing pancreatic polypeptide.
86
Congenital heart diseases associate with right-to-left shunting include: (Select 3)
- tricuspid atresia
- hypoplastic left heart syndrome
- aortopulmonary window
- patent ductus arteriosus
- tetralogy of Fallot
- subvalvular aortic stenosis
- ventricular septal defects
- atrial septal defects
- tricusped atresia
- hypoplastic left heart syndrome
- tetralogy of Fallot
-Right-to-left shunting (cyanotic) heart disease is associated with: Tetrology of Fallot, pulmonary atresia, triscupid atresia, transposition of the great vessels, truncus arteriosus, single ventricle, double-outlet ventricle, total anomalous pulmonary venous return and hypoplastic left heart.
With tricuspid atresia, blood can flow out of the right atrium only via a patent foramen ovale (PFO). A PDA or VSD is necessary for the blood to flow from the left ventricle to the pulmonary circulation.
