Regarding the effects of CO2 pneumoperitoneum during laparoscopic surgery:
B) ETCO2 levels may not correlate with PaCO2 levels in ASA III patients
ASA III patients have been shown to require greater minute ventilation to eliminate absorbed CO2. Additionally, PaCO2 levels may not correlate well with ETCO2 levels in ASA III patients. Pelvic insufflation (extraperitoneal) is associated with higher CO2 absorption than intraperitoneal insufflation. Peak airway pressures are consistently increased by pneumoperitoneum.
Electrolyte containing irrigation solutions are avoided during transurethral resection of the prostate because they:
D) 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.
The inhaled anesthetic agent with the highest vapor pressure is:
A) nitrous oxide
Nitrous oxide has the highest vapor pressure of the listed inhaled agents, with a vapor pressure of 38770 mmHg (745 psi). The vapor pressures of the other agents, in mmHg, are: desflurane - 669, isoflurane - 238 and sevoflurane - 157. Vapor pressures vary with ambient temperature.
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:
B) 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.
MAC-BAR is the:
B) 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.
In a 5-year-old, the appropriate length of an endotracheal tube from distal tip to incisors is:
C) 16 cm
Between 2 and 12 years of age, the following formula is commonly used to calculate ETT length:
Length from tip to incisors = 11 + age in years
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:
C) 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.
Difficulty with mask ventilation is most reliably predicted by:
B) The presence of a beard
Difficulty with mask ventilation is associated with the following (in decreasing order of probability of difficulty): presence of a beard, BMI > 26, lack of teeth, age > 55 and a history of snoring.
The area of myocardium most vulnerable to ischemia is the:
B) Left ventricular subendocardium
The subendocardium of the left ventricle is most vulnerable to ischemia since this is an area of greater systolic shortening. In addition, left ventricular subendocardium perfusion is almost entirely restricted to diastole, in contrast to the subendocardium of the right ventricle that receives most of its perfusion during systole.
The formation of active metabolites has NOT been associated with the use of:
D) Rocuronium
The 3-OH metabolites of both vecuronium and pancuronium possess about 50% of the neuromuscular blocking activity of parent compound. Succinylcholine is metabolized to choline, succinic acid and succinylmonocholine. Succinylmonocholine also has some neuromuscular blocking activity. A small amount of rocuronium is metabolized to the 17-OH compound, which lacks activity. Most rocuronium is excreted by the kidneys and liver as intact drug.
The rate of seroconversion after exposure of mucous membranes to HIV-infected blood is approximately:
C) 0.09%
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.
Actuation of the oxygen flush valve delivers 100% oxygen at a rate of:
B) 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
A decrease in cholinesterase activity has been associated with:
B) Burns
Burns, liver disease, 3rd trimester of pregnancy, carcinoma, 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 ECT therapy.
The incidence of headache with inadvertent dural puncture during epidural anesthesia is decreased:
B) 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.
Factors decreasing physiologic dead space include:
D) the 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-sypmathomimetics, advancing age and COPD all increase dead space.
As compared with plasma osmolality, hypertonic crystalloid solutions include:
D) D5 0.45NS
Normal plasma osmolality ranges between 280 - 290 mOsm/L. D5W is hypotonic in relation to plasma, with a tonicity of 253 mOsm/L. Both Ringer's lactate and D5 0.25NS are isotonic solutions, with tonicities of 273 and 355 mOsm /L respectively. D5 0.45NS is hypertonic with a tonicity of 432 mOsm/L.
Selective adrenergic stimulation of the β2-receptor results in:
A) Increased insulin secretion
β2-receptor stimulation results in: increased insulin secretion, bronchodilation, increased salivary gland secretion, decreased upper GI motility, gluconeogenesis, pupilary dilation and detrusor muscle relaxation. Increased heart rate is a result of β1-receptor stimulation. Pupilary constriction (miosis) is the result of parasympathetic stimulation.
Allergic reactions are most commonly seen with the use of:
A) Neuromuscular blockers
Muscle relaxants are responsible for more than 60% of drug-induced allergic reactions during the perioperative period. It is estimated that 50% of patients who experience allergic reactions to a muscle relaxant will also exhibit sensitivity to other muscle relaxants. The cross-sensitivity among this class of drugs is secondary to their structure similarities; specifically the presence of one or more antigenic quaternary ammonium groups.
The most consistent clinical manifestation of aspiration pneumonitis is:
C) 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.
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:(Enter numerical answer below).
________ mL
70 - 110 mL
The full-term neonate has approximately 85 ml/kg total blood volume. Therefore:
- 4.2 kg x 85 ml/kg = 357 ml (blood volume)
- 357 ml x 48% = 171 ml (current red cell mass)
- 357 ml x 38% = 136 ml (allowable red cell mass)
- 171 ml - 136 ml = 35 ml (allowable red cell mass loss)
- 35 ml x 3 = 105 ml (allowable blood loss)
Hormones secreted by the neurohypophysis include:
A) Oxytocin
The neurohypophysis is another term for the posterior pituitary gland. The hormones of the neurohypophysis, oxytocin and antidiuretic hormone (vasopressin), are synthesized in the hypothalamus and stored in the posterior pituitary. Stimulus for the release of these hormones arises from osmoreceptors in the hypothalamus that sense plasma osmolality.
Pancreatic somatostatin producing cells in the Islets of Langerhans are:
D) 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.
Congenital heart diseases associate with right-to-left shunting include:
D) Tricuspid atresia
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.
The maximum leakage current allowed in operating room equipment is:
A) 10 μA
10 μA has been established as the maximum allowable leakage current. This amount of current is below the threshold of perception (1mA) as well as below the threshold for risk of microshock.
Causes of normal-anion-gap acidosis include:
B) 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.
Carbonic anhydrase inhibitors are used in the treatment of:
A) 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.
Hypoxemia during one-lung anesthesia is most effectively treated by:
D) 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.
Sympathetic blockade during acute herpes zoster has been shown to:
B) Reduce the incidence of postherpetic neuralgia
Sympathetic blockade within 2 months of the onset of herpes zoster has been shown to significantly reduce analgesic requirements and reduce the incidence of postherpetic neuralgia. Once the neuralgia is established however, blocks are usually ineffective.
Branches of the femoral nerve anesthetized during an ankle block include the:
B) 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.
Pulmonary complications from advanced hepatic disease with cirrhosis include:
B) Increased intrapulmonary shunting
Pulmonary manifestations associated with cirrhosis include: increased intrapulmonary shunting, decreased FRC, pleural effusions, restrictive ventilatory defect and respiratory alkalosis.
An anxiolytic herbal medication associated with a decrease in the requirement of inhaled anesthetic agent (MAC) is
B) Valerian
Both valerian and kava have been shown to have a GABA-mediated hypnotic effect and by this mechanism decrease MAC.
A decrease in pseudocholinesterase activity has been associated with the use of: (Select 3)
a) Pancuronium
b) Esmolol
c) Droperidol
d) Vecuronium
e) Metoclopramide
f) Magnesium sulfate
g) Dantrolene
h) Rocuronium
a) Pancuronium
b) Esmolol
e) Metoclopramide
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.
During the delivery of an anesthetic in the radiology department, full E-cylinders of nitrous oxide and oxygen are being used. If a 3:2 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:
D) 745 psi
Nitrous oxide has a critical temperature of 37C. This allow 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 psi. 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.
The formation of metanephrine is the result of:
A) 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).
Characteristics of the dystrophic phase of complex regional pain syndrome type I include:
A) Cold, sweaty skin
Complex regional pain syndrome type I, previously known as reflex sympathetic dystrophy, is characterized by 3 phases: acute, dystrophic and atrophic. The dystrophic phase usually occurs 3 - 6 months after an inciting incident and is characterized by cold sweaty skin, some degree of muscle wasting with osteoporosis and pain that is described as diffuse and throbbing.
An action potential characterized by a spike followed by a plateau phase is seen in:
C) Cardiac muscle cells
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.
During mediastinoscopy the risk of air embolization is greatest:
C) during spontaneous ventilation
Air embolization is seen with mediastinoscopy as a result of the 30o elevation of the head. This risk is increased if the patient is spontaneously ventilating, secondary to the negative intrathoracic pressures generated during inhalation
Autonomic hyperreflexia:
B) can precipitate pulmonary edema
Autonomic hyperreflexia should be suspected in patients with lesions above T6. Regional anesthesia and deep general anesthesia are effective in preventing autonomic hyperreflexia. Surgical stimulation in these patients without adequate anesthesia can result in pulmonary edema, myocardial ischemia and cerebral hemorrhage.
During placement of a lumbar epidural using a midline approach, the needle passes through the: (Select 3)
F) Supraspinous ligament
a) Intraspinous ligament
e) Ligamentum flavum
Passing anteriorly from the skin to the epidural space are the following structures: skin, subcutaneous tissue, supraspinous ligament, intraspinous ligament, ligamentum flavum.
Interpleural analgesia can be accomplished by placing local anesthetic:
D) 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. Pneumothorax is a significant complication if the needle or catheter penetrates the visceral pleura.
The synthesis of acetylcholine from acetylcoenzyme A and choline is catalyzed by:
C) Choline acetyltransferase
The synthesis of acetylcholine occurs in the cholinergic nerve terminal. Acetyl Co-A and choline combine to form acetylcholine. This reaction is catalyzed by the enzyme choline acetyltransferase.
The primary causative factor in the development of persistent pulmonary hypertension (PPH) in the neonate is:
B) 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.
Electrocardiographic changes seen with hypokalemia include:
B) Increasingly prominent U waves
Electrocardiographic changes seen with hypokalemia include:
· T wave flattening/inversion
· ST segment depression
· increased P wave amplitude
· prolongation of the P-R interval
· increasingly prominent U waves
Deleterious effects of hypothermia include: (Select 2)
B) Impaired renal function
d) 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
Prior to pneumonectomy, split lung function testing is indicated in the patient with:
D) A PaCO2 of 49 mm Hg 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 mmHg
· FEV1 > 2 L
· Predicted postop FEV1 > 800 mL
· Maximum VO2 > 10 mL/kg/min
· FEV1/FVC > 50% of predicted
Mechanisms of renal compensation during acidosis include:
D) Increased production of ammonia
The renal response to acidemia is:
· increased reabsorption of bicarbonate anion
· increased excretion of hydrogen ion in the form of titratable acids
· increased production of ammonia
Although increased carbon dioxide elimination is a compensatory mechanism in acidemia, it is accomplished by increased alveolar ventilation.
Postintubation croup:
C) is secondary to inflammation at the level of the cricoid
Postintubation croup usually occurs at the level of the cricoid, since this is the narrowest part of the pediatric airway. Croup is less common with endotracheal tubes that are uncuffed and small enough to allow a gas leak at 10 - 25 cm H2O. Postintubation croup is associated with early childhood (1 - 4 years). Unlike laryngospasm, postintubation croup is seen some time after extubation, usually within 3 hours.
Closing capacity is defined as:
A) 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.
Dantrolene: (Select 2)
a) Depends on an extracellular mechanism to achieve muscle relaxation
b) Inhibits calcium ion release from the sarcoplasmic reticulum
c) Can also be used in the treatment of thyroid storm
d) Therapy should not be repeated after an MH episode has terminated
e) Has a half-life of approximately 12 hours
b) Inhibits calcium ion release from the sarcoplasmic reticulum
c) Can be used in the treatment of thyroid storm
Dantrolene binds with the Ryr1 receptor and inhibits calcium ion release from the sarcoplasmic reticulum. Dantrolene's effects are intracellular and may result in muscle weakness and ventilatory insufficiency. The half-life of dantrolene is approximately 6 hours. Dantrolene has also been used to treat neuroleptic malignant syndrome and thyroid storm.
The elimination half-life of a drug:
B) Is inversely proportional to the clearance
The elimination half-life of a drug is proportional to the volume of distribution and inversely proportional to the rate of clearance.
