Flashcards in Practice III Deck (125):
The majority of the venous return from the myocardium enters the:
-superior vena cava
-great cardiac vein
The great, middle and posterior left cardiac veins as well as the oblique vein of Marshall empty into the coronary sinus. The Thebesian veins, which transverse the myocardium, empty into the various chambers, but constitute only about 15% of the myocardial venous return.
When performing a caudal anesthetic, proper placement of the needle(s) is at:
(Make your selection by clicking on the appropriate area of the figure)
Caudal anesthesia can be thought of as a distal approach to the epidural space. With the patient prone or in the lateral position, the sacral hiatus is identified and a short-beveled needle is inserted midline between the cornua at a steep angle. When the canal is entered, the needle is lowered parallel to the sacrum and advanced into the epidural space.
Concerning intraocular pressure:
-the most significant hemodynamic parameter determining intraocular pressure is arterial blood pressure
-volatile anesthetic agents lower intraocular pressure
-hyperventilation will increase intraocular pressure
-increased PaO2 will lower intraocular pressure
volatile anesthetic agents lower intraocular pressure
Volatile anesthetic agents consistently lower intraocular pressure. The most significant hemodynamic parameter determining IOP is CVP. Hypoxia and hypercarbia both increase IOP, however IOP is not significantly changed by increases in PaO2.
The primary mechanism of heat loss from a patient in the operating suite is:
Radiation accounts for approximately 60% of the heat loss in the surgical patient. Other forms of heat loss in the surgical patient include evaporation (20%), convection (15%), and conduction (5%).
During a laparoscopic cholecystectomy in a 46-year-old female with a history of hypertension, you notice an acute rise in end-tidal carbon dioxide tension associated with a blood pressure of 78/45 mm Hg, and rales. Immediate therapy should include:
-correction of the volume overload with furosemide
-a 500ml bolus of NS
-asking the surgeon to release the pneumoperitoneum
-placement of the patient in reverse Trendelenberg position
asking the surgeon to release the pneumoperitoneum
Carbon dioxide embolism can result from unintentional insufflation of gas into an open vein. This may lead to hypotension, elevated end-tidal carbon dioxide levels, hypoxemia, and pulmonary edema. Treatment consists of immediate release of the pneumoperitoneum.
The polarographic oxygen analyzer is best represented by?
(Make your selection by clicking on the appropriate part of the figure)
The polarographic oxygen electrode (Clark electrode) consists of a voltage source and a current meter connected to platinum and silver electrodes immersed in a KCl solution. A membrane permeable to oxygen allows the diffusion of oxygen into the cell, where electrons are liberated by an oxidative reaction. The meter measures the current produced, with the current flow being proportional to the oxygen concentration.
A 78-year-old man is scheduled for a right carotid endarterectomy under general anesthesia. The most sensitive method for assessing cerebral perfusion during the procedure is:
-measurement of carotid stump pressures
-measurement of the oxygen content of jugular venous blood
-somatosensory evoked potential monitoring
EEG monitoring is the most sensitive method of assessing the adequacy of cerebral perfusion in the anesthetized patient.
Which of the following herbal medications may cause an increase in bleeding during surgery? (Select 2)
-St. John's wort
Garlic, Fish Oil
All of the following herbal medications may adversely affect clotting: alfalfa, capsicum, chamomile, dong quai, feverfew, fish oil, garlic, ginkgo biloba, ginger, ginseng, goldenseal, guarana, horse chestnut, and willow bark. These medications should be discontinued for at least two weeks preoperatively. Coagulation studies should be performed in patients who are actively taking these herbals.
Compensatory mechanisms that buffer increases in intracranial pressure include:
-increased cerebrospinal fluid production
-displacement of cerebrospinal fluid into the spinal canal
-increased intracranial venous blood volume
-decreased cerebrospinal fluid absorption
displacement of cerebrospinal fluid in to the spinal canal
Within limits, increases in intracranial volume result in only small increases in intracranial pressure. Major compensatory mechanisms include a displacement of CSF into the spinal canal, increased CSF absorption, decreased CSF production, and decreased cerebral blood volume - mostly venous.
A display of arterial blood gas values is shown (Click here to display values). By dragging & reordering the selections in yellow, match the blood gas values with the corresponding metabolic abnormality.
Respiratory acidosis - #1
Metabolic alkalosis - #2
Respiratory alkalosis - #3
Metabolic acidosis - #4
A list of diuretic sites of action is shown below. By dragging & reordering the selections in yellow, match the diuretic with the corresponding site of action.
Loop of Henle
Furosemide-Loop of Henle
Pulse oximetry employs the absorption of two specific frequencies of light by hemoglobin to determine the oxygen saturation. This is an application of:
The Beer-Lambert Law states that: (1) the luminance of perpendicular light on a surface is proportional to the inverse square of the distance it travels; (2) the luminance intensity of angled light is proportional to the cosine of the angle with the normal; (3) Luminance intensity decreases exponentially as the light travels through a medium. Analysis of the wavelength that is most absorbed corresponds to the concentration of that form of hemoglobin.
As compared to the classic LMA, advantages of the LMA ProSeal include:
-the ability to provide active gastric suctioning
-greater ease of insertion
-decreased peak inspiratory pressure
-the absence of a bite block
the ability to provide active gastric suctioning
The LMA ProSeal is a double lumen LMA allowing gastric drainage. In addition, the ProSeal has a bite block and allows a greater peak inspiratory pressure to be delivered.
A display of oxyhemoglobin dissociation curves is shown (Click here to display curves). By dragging & reordering the selections in yellow, match the physiologic state with the corresponding curve.
On a warm summer day, e-cylinders of oxygen and nitrous oxide are brought from the hospital loading dock into the air-conditioned operating room. The effect of the declining temperature on the e-cylinders is to:
-cause a decrease in tank pressure in both cylinders
-cause a decrease in tank pressure of the oxygen cylinder only
-cause a decrease in tank pressure of the nitrous oxide cylinder only
-cause a decrease in the critical temperature of the oxygen
cause a decrease in tank pressure in both cylinders
Following the Combined Gas Law, a decline in ambient temperature will cause a decrease in both tank pressure and tank volume. Since the critical temperature of oxygen is -118 C, oxygen cannot exist as a liquid at ambient temperatures.
The most common cause of chronic liver disease in the United States is:
-non-alchoholic fatty liver disease
non-alchoholic fatty liver disease
Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the US. It is defined as fat accumulation in the liver exceeding 5% by weight. It has been estimated that 24% of American adults have NAFLD. Risk factors for its development are Type II DM and obesity; it is more prevalent in women, and it usually manifests in the fifth and sixth decades of life.
When using a pulmonary artery catheter to measure thermodilution cardiac output, factors that may cause a falsely elevated measurement include:
-pulmonic valve insufficiency
pulmonic valve insufficiency, VSD
Recirculation of blood and injectate, in either the right atrium or right ventricle, can cause a falsely elevated measurement of CO. As a result, ASD, VSD, tricuspid regurgitation, and pulmonic regurgitation can cause a falsely elevated measurement of CO.
-it most commonly seen in the neonatal population
-is best treated with morphine 12.5 mg IV
-may increase O2 consumption and CO2 production by up to 200%
-decreases cardiac output and minute ventilation
may increase O2 consumption and CO2 production by up to 200%
Post-operative shivering may increase O2 consumption and CO2 production by up to 200%. It increases cardiac output and minute ventilation as well, which may precipitate ventilatory failure in patients with limited reserve and myocardial ischemia in patients with CAD. Along with restoration of normothermia, meperidine (12.5-25 mg IV) is most efficacious in suppressing post-operative shivering.
A 28-year-old male is undergoing an emergent laparotomy after sustaining multiple injuries in a motor vehicle accident. As a result of trauma to the inferior vena cava, the patient receives 12 units of packed red blood cells (PRBC's), 3 units of fresh frozen plasma and 8 units of platelets over the course of an hour. During this period you notice a widening of the QRS complex with lengthening of the QT-interval on the ECG. The most appropriate therapy at this time is to:
-increase the rate of infusion of the PRBC's
-stop the administration of all blood products
-administer intravenous calcium gluconate
-increase the rate of infusion of NS
administer intravenous calcium gluconate
Stored blood contains citrate to chelate the ionized calcium and prevent coagulation. During rapid infusion, greater than 1cc/kg/min, of blood products, patients can develop hypocalcemia secondary to citrate intoxication. Hypotension and ECG evidence of hypocalcemia, widening of the QRS complex and lengthening of the QT-interval, can be effectively treated with ionized calcium.
Risk factors for pregnancy induced hypertension (PIH) include:
-multiple previous pregnancies
-low blood pressure prior to pregnancy
PIH is most prevalent in primigravidas. The pathophysiology of this disease is unknown. Additional risk factors include: extremes of maternal age, multiple births, pre-pregnancy hypertension, diabetes mellitus, asthma, renal disease and autoimmune disease.
Advantages of the piston ventilator include (Select 2):
-indentifiable auditory cues during ventilation
-use of air instead of oxygen as a driving gas
-improved accuracy of delivered tidal volume
-decreased dead space
-compensation of gas loss in cases of bellows leak
fresh-gas decoupling, improved accuracy of delivered tidal volume
Advantages of the piston ventilator include: it's very quiet, no PEEP is applied, fresh-gas decoupling, greater volume precision and no driving gas is required. Disadvantages include: loss of familiar visible behavior of the standing bellows during a disconnect, difficulty in hearing the ventilatory cycle, hypoventilation if a bellows leak occurs and difficulty accommodating non-rebreathing circuits.
An acquired decrease in the level of plasma cholinesterase activity is associated with:
Pregnancy causes an acquired decrease in plasma cholinesterase activity. Alcoholism, obesity, thyrotoxicosis, hemochromatosis, nephrotic syndrome and electroshock therapy all cause acquired increases in plasma cholinesterase activity.
During your preoperative evaluation, the rhythm strip below is obtained. This ECG tracing is consistent with:
-acute myocardial infarction
-complete heart block
-intraventricular conduction delay
-non-specific ST-T wave changes
intraventricular conduction delay
The QRS duration on the ECG above is greater than 0.12 seconds indicating an intraventricular conduction delay. Although ST - T wave abnormalities are present, they are expected in patients with bundle branch block patterns. Each QRS complex is preceded by a P wave and a PR interval less than 0.20 seconds, indicating no heart block. Since the lead of the tracing is unknown, we cannot determine if this is a left or right bundle branch block pattern.
-increases the MAC of volatile anesthetics
-causes CNS excitation via selective a-2 agonism
-reduces the incidence of perioperative hypothermia
-has analgesic properties
has analgesic properties
Dexmedetomidine (Precedex) is a more selective α-2 agonist than clonidine. It produces sedation/anxiolysis, it is an antisialagogue, it promotes hemodynamic stability, homeostatic reflexes remain intact, and it is a potent analgesic. It also attenuates opioid-induced rigidity in animals.
When performing spinal anesthesia, the largest vertebral interlaminal space can be found at:
L5 - S1
Anatomically, this is the largest interlaminal space and can be used to achieve spinal anesthesia with the Taylor approach.
A 53-year-old female is scheduled for a laparoscopic cholecystectomy. Past surgical history is notable for cardiac transplantation 3 years ago. Prior to induction, the vital signs are: temp 98.2, HR 88, BP 128/72. During insufflation, the patient becomes hypotensive and bradycardic. The most appropriate therapy in this patient is:
The transplanted heart cannot respond to indirect acting agents such as ephedrine and even dopamine. Vagolytics such as atropine and glycopyrrolate will have no effect as the donor heart is essentially vagotomized. Beta effects of epinephrine and norepinephrine are exaggerated in heart transplant recipients. Isoproterenol is the mainstay of chronotropic therapy in these patients.
Cluster headaches (Select 2):
-are seen more frequently than migraine headaches
-occur more frequently in men
-are characterized by a dull aching pain in the occipital area
-are usually associated with an aura
-oar often associated with the presence of Horner's syndrome
occur more frequently in men, are often associated with the presence of Horner's syndrome
Cluster headaches are classically periorbital and unilateral and occur in clusters 1 - 3 times a day for a 4 - 8 week period. Cluster headaches are much less common than migraine headaches and occur predominantly (90%) in males. Headaches usually occur abruptly with no aura and are described as stabbing. Red eye, tearing, nasal stuffiness and ptosis (Horner's syndrome) are classic findings.
A list of pathophysiologic conditions resulting in acid-base abnormalities is shown below. By dragging & reordering the selections in yellow, match the condition with the corresponding acid-base abnormality.
Renal Failure-Metabolic Acidosis
Fentanyl Abuse-Respiratory Acidosis
Cauda equina syndrome has been associated with (Select 3):
-the use of hyperbaric 5% lidocaine
-the use of hypobaric tetracaine
-an unexpected high level of anesthesia
-the use of micropore continuous spinal catheters
-the maldistribution of local anesthetic
-the addition of fentanyl to the anesthetic solution
the use of hyperbaric 5% lidocaine, the use of micropore continuous spinal catheters, the maldistribution of local anesthetic
Cauda equina syndrome after neuraxial anesthesia has been associated with the use of 5% lidocaine, micropore spinal catheters and the maldistribution of local anesthetic.
Local anesthetics indicated for use in an intravenous block include:
Lidocaine 0.5% is the only local anesthetic approved for use in an IV regional anesthetic (A.K.A. Bier block) by the FDA. Vasoconstrictors should not be added to the solution. Bupivacaine is contraindicated for use as an IV regional anesthetic.
Vasodilator therapy is indicated in the treatment of:
-congestive heart failure
-right ventricular failure
-cyanosis associated with Tetralogy of Fallot
congestive heart failure, right ventricular failure, aortic insufficiency
Vasodilator therapy is effective in reducing both preload and afterload in patients with CHF, aortic insufficiency and right ventricular failure. The preload and afterload reductions with vasodilator therapy will cause a reduction in blood pressure and cardiac output in most patients with mitral or aortic stenosis. Cyanotic episodes associated with the Tetralogy of Fallot are treated with methods to increase left ventricular afterload, such as phenylephrine administration.
An infant is born with Transposition of the Great Arteries (TOGA). Until corrective surgery is performed, palliation with a Rashkind balloon septostomy and pharmacologic maintenance of a patent ductus arteriosis is necessary. This is best achieved with the use of:
-high inspired FiO2
PGE1 infusion rates of 0.01-0.03 mcg/kg/min will maintain patency of the ductus arteriosis before corrective surgery for "ductal dependent" cardiac lesions such as TOGA. High inspired concentrations of FiO2 and indomethacin facilitate closure of the PDA.
A 35-year-old man is receiving N2O:O2 at 2:1 liters/min with a propofol infusion for a right knee arthroscopy. At sea level, the partial pressure of oxygen being received by the patient is:
Sea level exerts a barometric pressure of 760 mmHg. Since the concentration of oxygen is known to be 33% (2:1 mixture), the partial pressure of oxygen is 760 x 0.33 = 253.33 mmHg.
During neonatal resuscitation, which of the following medications may be administered via the endotracheal tube?
The following medications may be administered via the endotracheal tube during neonatal resuscitation:
Lidocaine, Atropine, Naloxone, Epinephrine.
These may be remembered using the mnemonic "LANE". During adult CPR, vasopressin may also be administered through the ETT.
A 70-year-old man is undergoing monitored anesthesia care with sedation for a hemorrhoidectomy. The patient is receiving propofol at 100 mcg/kg/min. Ten minutes after receiving 20 ml of 2% lidocaine with 1:200,000 epinephrine, the blood pressure is 65/45, the heart rate is 63/min and the ECG shows a widened QRS complex. The most appropriate management is to:
-administer ephedrine 10 mugs and continue with the surgery
-administer 0.4 msg of atropine
-administer 150 mg of amiodarone
-administer hemodynamic support, terminate the case and obtain an ECG and cardiac evaluation
administer hemodynamic support, terminate the case and obtain an ECG and cardiac evaluation
ECG changes associated with bradycardia and hypotension may indicate myocardial ischemia. Appropriate therapy would include the termination of surgery and a cardiac evaluation.
Your patient arrives to the OR for total parathyroidectomy with reimplantation. Possible physical derangements secondary to hyperparathyroidism include:
-prolongation of the QT-interval
heart block, nephrolithiasis
Physical derangements secondary to hyperparathyroidism may mirror those found with hypercalcemia. They include:
weight loss, polydipsia, hypertension, heart block, weakness, lethargy, headache, insomnia, apathy, depression, bone pain, arthritis, pathologic fractures, anorexia, nausea, vomiting, epigastric pain, constipation, polyuria, and hematuria. Nephrolithiasis is the most common finding in patients with hypercalcemia.
The upper-lip-bite test is defined as Class I when the patient:
-is able to move the lower incisors in line with the upper incisors and bite the upper lip below the vermillion border
-cannot advance the lower incisors to be in line with the upper incisors and cannot bite the upper lip
-is able to firmly seal upper and lower lips with only the vermillion borders showing
-can protrude the lower incisors past the upper incisors and can bite the upper lip above the vermilion border
can protrude the lower incisors past the upper incisors and can bite the upper lip above the vermillion border
The upper-lip bite test, also known as the mandibular protrusion test, demonstrates the patient's ability to extend the mandibular incisors past the maxillary incisors. The purpose of the test is to assess the mobility of the temporomandibular joint and architecture of the dentition. The test has been found to be a valuable assessment tool in the assessment of the difficult airway when used in combination with other assessment techniques.
In patients undergoing endoscopic retrograde cholangiopancreatography:
-light sedation should be employed to allow patient cooperation during the procedure
-pre-procedure glycopyrrolate should be given to reduce the incidence of sphincter spasm
-significant comorbiidites are frequently present
-sinus bradycardia is commonly encountered during stent placement
significant comorbidities are frequently present
During ERCP, patients usually experience discomfort and general anesthesia or deep sedation techniques are recommended for the procedure. Sphincter of Oddi manometry may be performed, in which case drugs that affect sphincter pressure such as atropine, glycopyrrolate, glucagon, and various opioids should be avoided preoperatively. Patients presenting for ERCP may have significant comorbidities, including acute cholangitis with septicemia, jaundice with liver dysfunction and coagulopathy, bleeding from esophageal varices resulting in hypovolemia, or biliary stricture following major hepatobiliary surgery, including liver transplantation. Sinus tachycardia is a frequent occurrence, especially if anticholinergic agents have been administered by the endoscopist.
A 46-year-old man is undergoing general anesthesia for a shoulder arthroscopy. His past medical history is significant for type II diabetes mellitus and hypertension. One hour into the procedure the following labs are obtained:
pH = 7.24 PO2 = 320 mmHg
PCO2 = 26 mmHg HCO3 = 23 mEq/L
Sodium = 141 mEq/L Chloride = 102 mEq/L
Potassium = 3.0 mEq/L BUN = 23 mg/dL
The most likely cause of the acidosis is:
-inadequate alveolar ventilation
This patient is demonstrating metabolic acidosis with respiratory compensation. In addition, this is a wide-anion-gap acidosis in a patient with a history of diabetes. Since there is no evidence of renal failure, only lactic acidosis meets all these criteria.
Common complications associated with Trisomy 21 syndrome include:
-abnormally think and viscous respiratory secretions
-increased dead space
-atlanto-occipital subluxation during laryngoscopy
-increased incidence of post-extubation croup
-potential for paradoxic air embolus from air in the IV tubing
atlanto-occipital subluxation during laryngoscopy, increased incidence of post-extubation croup, potential for paradoxic air embolus from air in the IV tubing
Common problems associated with Trisomy 21 (A.K.A. Down Syndrome) include airway issues such as short neck, large tongue, subglottic stenosis, tracheoesophageal fistula, and a potential for atlanto-occipital dislocation during laryngoscopy due to laxity of the supporting ligaments. Cardiac malformations occur in approximately 40% of these patients; the majority are endocardial cushion defects and VSDs.
Evidence that a pulmonary artery catheter has advanced from the right ventricle into the pulmonary artery includes:
-a sudden increase in systolic pressure
-a sudden increase in diastolic pressure
-loss of the dicrotic notch
-reappearance of the central venous pressure tracing
a sudden increase in diastolic pressure
The passage of the pulmonary artery catheter from the right ventricle into the pulmonary artery is evidenced by a sudden increase in diastolic pressure caused by the the closed pulmonic valve preventing return of ejected blood into the right ventricle.
Modern vaporizers are more resistant than older vaporizers to the "pumping effect" because:
-unidirectional valves prevent retrograde gas flow
-volatile anesthetic is vaporized in a separate reservoir
-variable bypass design is no longer used
-flow of gas through the vaporization chamber is tightly controlled
unidirectional valves prevent retrograde gas flow
Modern vaporizers are more resistant than previous models to the effects of intermittent back pressure, the so-called "pumping effect" that increases vaporizer output. This is because most incorporate unidirectional valves and other mechanisms to prevent retrograde flow.
The most common complication seen after blood transfusion is:
-acute hemolytic reaction
-delayed hemolytic reaction
Febrile reactions are relatively common, occurring in 0.5% per unit transfused.
The definitive treatment for postdural puncture headache is:
-autologous blood patch
autologous blood patch
Although postdural puncture headache (PDPH) may be ameliorated by supine position, analgesics, caffeine, and hydration, the definitive treatment is autologous blood patch. Approximately 15-20 ml of autologous blood injected into the epidural space close to or at the site of puncture should provide dramatic relief of PDPH.
After induction of general anesthesia in a 67-year-old man undergoing an abdominal aortic aneurysm repair, a pulmonary artery (PA) catheter is placed. Initial pulmonary artery pressures are 42/25 with a pulmonary capillary wedge pressure of 24 mmHg. The patient's past medical history is significant for long-standing mitral stenosis. Your interpretation of the PA catheter data is:
-mitral stenosis caused an overestimation of LVEDP
-mitral stenosis causes an underestimation of LVEDP
-mitral stenosis does not affect the evaluation of LVEDP
-the PA catheter data is inconsistent with mitral stenosis and further cardiac workup is required
mitral stenosis causes an overestimation of LVEDP
Pathologic obstruction of blood flow from the pulmonary venous circuit into the left ventricle can cause an overestimation of LVEDP. As a result, pulmonary vein obstruction, atrial myxoma, left atrial clot, and mitral stenosis can give a falsely high estimation of LVEDP.
The C-Trach supraglottic airway device:
-has two lumens to allow gastric suctioning
-uses a separate esophageal balloon to reduce the incidence of aspiration
-allows visualization of the larynx after insertion
-cannot be used to attain endotracheal intubation
allows visualization of the larynx after insertion
The LMA CTrach is an advanced model of the LMA Fastrach intubating LMA that has imaging capability of the larynx after insertion of the LMA through an attachable video monitor. It is a single lumen device.
Current applied directly to the myocardium from invasive monitors can induce ventricular fibrillation with as little as:
With direct application of current to the myocardium, from intracardiac invasive monitors or pacing wires, currents of as low as 100 microamps have been shown to cause ventricular fibrillation. This is referred to as microshock.
A subcutaneous injection of 5-10 mL of local anesthetic placed between the anterior tibial artery and the lateral malleolus will block the:
-superficial peroneal branches
-posterior tibial nerve
superficial peroneal branches
During an ankle block, injections are made at five separate nerve locations: the superficial and deep peroneal nerves, the saphenous nerve, the sural nerve and the posterior tibial nerve. A subcutaneous ridge of 5 - 10 mL of local anesthetic laid along the skin crease between the anterior tibial artery and the lateral malleolus will anesthetize the superficial peroneal branches.
Factors associated with postdural puncture headache include:
-postural changes in intensity
-the type of local anesthetic used
-occurrence within 1 hour following the spinal anesthetic
-no association with nausea or photophobia
postural changes in intensity
Typically a postdural puncture headache is bilateral, extends into the neck, is associated with photophobia and nausea, occurs 12 - 72 hours after the dural puncture and is aggravated by sitting up.
The respiratory bronchioles constitute which generation(s) of the tracheobronchial tree?
-5th - 16th
-17th - 19th
-20th - 22nd
Dichotomous division of the airways, starting with the trachea and ending with the alveolar sacs is estimated to involve 23 subdivisions or generations of the tracheobronchial tree. The trachea constitutes generation 0, while the alveolar sacs constitute generation 23. The respiratory bronchioles occur at the 17th to the 19th generation from the trachea.
When terminating an anesthetic, factors that determine the transfer of anesthetic gases from the blood to the alveoli include the (Select 2):
-degree of protein biding of the anesthetic
-capillary-alveolar suface area
-differences in the partial pressures of anesthetic gas in the lung and blood
-MAC of the anesthetic agent
-specific gravity of the volatile anesthetic agent
-vapor pressure of the anesthetic agent
capillary-alveolar surface area, differences in the partial pressures of anesthetic gas in the lung and blood
Transfer of anesthetic gases from the blood to the lung when terminating an anesthetic is determined by Fick's Law. The rate of diffusion is governed by the membrane surface area, temperature, differences in partial pressure between the blood and alveoli, and the thickness of the alveolar-capillary membrane.
After Caesarian delivery, your patient exhibits uterine atony which is unresponsive to both oxytocin and methylergonovine. The obstetrician requests that carboprost (prostaglandin F2α) be administered. Correct statements regarding this agent include (Select 2):
-it may cause hypotension
-it may cause bronchoconstriction
-it exhibits an antidiuretic effect in large doses
-it may increase pulmonary vascular resistance
-it may cause decreased cardiac output
it may cause bronchoconstriction, it may increase pulmonary vascular resistance
Prostaglandins (prostaglandin F2α) are used if uterine contraction is not effective after administration of oxytocin or ergot alkaloids. Smooth muscle contraction from prostaglandins such as carboprost tromethamine (Hemabate) may produce bronchoconstriction, hypertension, and pulmonary vasoconstriction in the parturient.
Somatosensory evoked potential monitoring is effective in determining the integrity of the:
-ventral(anterior) spinal cord
-dorsal(posterior) spinal cord
-auditory and brain stem function
dorsal (posterior) spinal cord
Somatosensory evoked potentials (SSEP) involve the stimulation of a peripheral nerve and recording the response through the sensory pathways. Since the sensory pathways are largely restricted to the dorsal spinal cord, SSEPs are an effective monitor of the integrity of the dorsal cord. Motor pathways are largely found in the ventral spinal cord and are not effectively monitored by SSEPs. Auditory EPs and visual EPs monitor the auditory/brain stem, and visual pathways respectively.
A true statement regarding renal function in the elderly is:
-serum creatine remains relatively stable secondary to an overall decease in muscle mass
-renal mass is decreased approximately 40% by age 70
-creatinine clearance decreased by 5% each year after age 40
-elderly are more responsive to the effects of ADH
serum creatinine remains relatively stable secondary to an overall decrease in muscle mass
Serum creatinine concentration remains normal in the elderly patient because the loss of skeletal muscle mass imposes a progressively smaller creatinine load. Renal mass is decreased by approximately 30% by age 80 and creatinine clearance decreases approximately 1% per year each year after 40. Elderly are less receptive to the the effects of ADH.
A 57-year-old man is receiving continuous epidural fentanyl for control of postoperative pain following a low-anterior resection. Four hours after initiation of the epidural infusion, the patient is complaining of severe itching of his lower extremities. The most effective means of controlling the pruritis is with the administration of:
Intravenous narcotic antagonists given in small quantities or as a continuous infusion are effective in controlling the pruritis associated with neuraxial narcotics. Also shown to be effective are ondansetron and mixed agonist-antagonist narcotics such nalbuphine. Antihistamines have limited effect.
Oxygen proportioning systems are designed to ensure that the concentration of oxygen delivered is not less than:
23 - 25%
Manufacturers equip anesthesia workstations with proportioning systems in an attempt to prevent creation and delivery of hypoxic mixtures of gasses. Nitrous oxide and oxygen are interfaced mechanically and/or pneumatically so that the minimum oxygen concentration at the common gas outlet is between 23 and 25% depending on manufacturer.
A 16-year-old female with a 6-year history of insulin dependent diabetes mellitus is scheduled for a wide-excision of a nevus on the back under general anesthesia. On the morning of surgery, the patient takes her full dose of insulin. Signs and symptoms of insulin overdose in this patient would include:
-positive urine test for ketones
-decreased blood pressure with bradycardia
The systemic manifestations of hypoglycemia result from catecholamine discharge. As a result, nervousness, diaphoresis, mydriasis, tachycardia, and hypertension are commonly seen.
As compared to younger patients, in elderly patients:
-there is a lower incidence of postop nausea and vomiting
-the most frequent cause of delayed awakening is hypothermia
-pulmonary function tests often reveal restrictive disease
-gastric pH is reduced
there is a lower incidence of post-operative nausea and vomiting
There is less nausea and vomiting in older adults. Nerve palsies and residual paresthesias are more common in the elderly patient. The most frequent cause of delayed awakening is typically due to oversedation and sustained
During an pneumonectomy performed with one-lung ventilation, the saturation falls gradually to 86% over 10 minutes. The most effective method of restoring the oxygen saturation to normal levels is:
-to introduce a small quantity of nitrous oxide for alveolar support
-the application of PEEP to the dependent lung
-to decrease the tidal volume and increase the rate of ventilation
-to periodically inflate the collapsed lung with oxygen
to periodically inflate the collapsed lung with oxygen
Consistently effective methods of treating hypoxemia during one-lung ventilation include: periodic inflation of the collapsed lung with oxygen, ligation of the ipsilateral pulmonary artery, CPAP to the collapsed lung.
Blood loss will be least with which of the following types of hip fracture?
The quantity of blood loss from a hip fracture correlates with the location of the fracture. Subtrochanteric and intertrochanteric fractures cause the greatest blood loss, followed by base of the femoral neck. Blood loss is reduced with transcervical or subcapital fractures because the surrounding capsule acts as a tourniquet.
The nervous system has exclusive control over the secretion of:
vasopressin, catecholamines and oxytocin
Release of vasopressin (ADH), catecholamines and oxytocin, is exclusively controlled by thenervous system. Catecholamines are released by stimulation of preganglionic sympathetic fibers. Oxytocin and vasopressin are released under hypothalamic control.
A display of ECG tracings is shown (Click here to display tracings). By dragging & reordering the selections in yellow, match the arrhythmia with the corresponding ECG.
2nd Degree Type I Block
First Degree Block
2nd Degree Type I Block-ECG 1
Third Degree Block-ECG 2
Atrial Flutter-ECG 3
First Degree Block-ECG 4
By weight, the largest constituent of soda lime is:
By weight, approximately 80% of soda lime is composed of calcium hydroxide. Other constituents include sodium (potassium) hydroxide 5%, and water 15%.
A 75-year-old patient returns to the OR actively bleeding for re-exploration of a partial glossectomy. Past medical history is remarkable for alcoholism and smoking. Which of the following airway devices would be most useful for the tracheal intubation of this patient?
-direct laryngoscopy with a Miller blade
-awake fiberoptic intubation
Intubating LMA is a viable option for tracheal intubation of an airway in which the view is obscured by blood. Combitube will secure the airway, but tracheal intubation is not guaranteed with its use.
A 62-year-old female is admitted to the PACU after a laparoscopic cholecystectomy. Her past medical history is significant for hypertension, obesity and hiatal hernia. Shortly after admission her oxygen saturation is 89% on nasal cannula. Rhonchi are noted in her right chest with diminished breath sounds noted on the right. These findings are most consistent with:
-congestive heart failure
Physiologic changes associated with gastric aspiration are pulmonary shunting, pulmonary edema and pulmonary hypertension. Wheezing, rhonchi, tachycardia and tachypnea are common physical findings. In this patient, having a laparoscopic procedure with a history of hiatal hernia and obesity, aspiration pneumonitis is the most likely cause.
According to the ideal gas law, one mole of any gas at 0o C and 1 atmosphere of pressure will occupy:
According to the universal gas law, one mole of gas at standard temperature and pressure (0o C and 1 atmosphere) will occupy 22.4 liters of volume.
A 42-year-old, 200-kg, 6-foot tall patient is scheduled for a duodenal switch procedure. From this information, the body mass index (BMI) of this patient is calculated to be:
The BMI is calculated as follows: BMI = weight / (height in meters)2. Extreme obesity is defined as a BMI > 40.
The earliest and most sensitive sign of the development of malignant hyperthermia is:
-unexpected elevation of ETCO2
-increase in body temperature
-masseter muscle rigidity
unexpected elevation of ETCO2
Unexpected elevation of end-tidal carbon dioxide in the absence of equipment malfunction is the earliest and most sensitive sign of MH.
Evaporative heat loss may be reduced by using:
-a warming blanket
-application of forced air over the patient
-humidifiers in the anesthesia circuit
-gas flows that exceed minute ventilation
humidifiers in the anesthesia circuit
Mechanisms of heat loss in the OR include radiation, conduction, convection and evaporation. The use of humidification in the anesthesia circuit reduces evaporative heat loss. Warming the OR table is effective in reducing conductive loss and warm hot air will reduce convective loss.
Choose the correct relationship between alveolar, arterial, and venous pressures in Zone II of the lung:
-PA > Pv > Pa
-Pa > PA > Pv
-PA > Pa > Pv
-Pa > Pv > Pa
Pa > PA > Pv
Zone I PA > Pa > Pv
Zone II Pa > PA > Pv
Zone III Pa > Pv > PA
Zone I represents alveolar dead space because alveolar pressure continually occludes the pulmonary capillaries. In Zone II, pulmonary capillary flow is intermittent; capillaries are occluded only during the inspiratory portion of the respiratory cycle. Pulmonary capillary flow is constant in Zone III, and it exceeds alveolar pressure, representing shunt.
In a 70-kg patient, the percentage of cardiac output perfusing the coronary arteries is approximately:
In a 70-kg person, approximately 4 to 5%, or 225 ml/min, of the cardiac output is directed to the coronary circulation.
72. The estimated blood loss for a transurethral resection of the prostate (TURP) lasting for one hour is: 180 - 500 ml
EBL is difficult to quantify during TURP because of the use of irrigating solutions. Blood loss averages approximately 3 - 5 mL/minute of resection time and is usually 200 - 300 ml total.
From the images below, the Mallampati II classification is best depicted by:
The Mallampati Classification: Class I - uvula, faucial pillars, soft palate visible; Class II - faucial pillars and soft palate visible; Class III - soft and hard palate visible; Class IV - hard palate only visible.
A 72-year-old patient presents to the OR for an ORIF of a femoral head fracture. Past surgical history includes CABG X 4 with subsequent pacemaker insertion for 3 AV block. Special considerations for this patient would include:
-placement of the current return pad for electrocautery as far as possible from the pulse generator
-use of electrocautery in short burst
-use of ungrounded power to the electrocautery
-disabling the pacemaker during the surgical procedure
-use of bipolar cautery or ultrasonic scalpel when possible
-infusion of isoproterenol to maintain heart rate during electrocautery use
placement of the current return pad for electrocautery as far as possible from the pulse generator, use of electrocautery in short bursts, use of bipolar cautery or ultrasonic scalpel when possible
It is essential that patients with pacemakers be protected during surgeries where electrocautery may be used. Placement of the electrocautery return pad must be as far as possible from the pulse generator to avoid passage of current through the pulse generator and/ or cardiac leads. Electrocautery should be delivered in short bursts, and bipolar electrocautery or the ultrasonic (Harmonic) scalpel should be used whenever possible.
The estimated blood loss for a transurethral resection of the prostate (TURP) lasting for one hour is:
180 - 500 ml
EBL is difficult to quantify during TURP because of the use of irrigating solutions. Blood loss averages approximately 3 - 5 mL/minute of resection time and is usually 200 - 300 ml total.
A 16-year-old female is in the intensive care unit following a fall in gymnastics class and a closed head injury. A subdural bolt is in place for monitoring of intracranial pressure. The following results are obtained: BP - 140/80 mmHg, pulse - 68/min, CVP - 9 mmHg, ICP - 25 mmHg. Her cerebral perfusion pressure is:
Cerebral perfusion pressure (CPP) is the difference between mean arterial pressure (MAP) and ICP or CVP, whichever is greater. In this case the MAP is 100 mmHg with an ICP of 25 mmHg, resulting in a CPP of 75 mmHg.
Cyclooxygenase (COX) inhibition has been shown to occur after the administration of:
acetaminophen, ketorolac, acetylsalicylic acid
The analgesic and antipyretic effects of these drugs are a result of their ability to inhibit cyclooxygenase. Ondansetron is a 5-HT receptor antagonist. Both clonidine and dexmedetomidine exert their effects through central alpha-2 agonistic actions.
Rapid opening of an oxygen e-cylinder can result in the creation of very high temperatures within the machine. This sudden temperature increase is a result of:
Rapid expansion or compression of gasses may exceed the speed of energy equilibration with the surrounding environment. This is referred to as an adiabatic process and entails no increase or decrease in the system's energy.
The administration of 100 mL of 25% albumin is expected to raise the plasma volume by approximately:
Twenty-five percent human serum albumin, a concentrated colloid, expands plasma volume by approximately 400 mL for each 100 mL infused.
A 63-year-old male is undergoing a small bowel resection. Ninety minutes into the case the patient gradually develops hypertension and tachycardia, which is unresponsive to increased anesthetic depth. The most appropriate medication to administer at this time is:
Beta-adrenergic blockade is a good choice in this patient with both tachycardia and hypertension. Vasodilator therapy can be associated with worsening tachycardia.
Therapeutic interventions best avoided in the premature neonate include:
-intubation with a 2.5 ETT
-time cycled positive pressure ventilation with an I:E ratio of 1:1
-FiO2 > 0.5
-slow IV infusion of salt-poor albumin 10 mg/kg
FiO2 > 0.5
Administration of oxygen must be done with caution in the premature infant. Retinopathy of prematurity (ROP) develops in 84% of premature infants and is the result of hyperproliferation and fibrosis of the retinal vasculature, leading to retinal detachment and blindness. Hyperoxygenation promotes this disorganized proliferation of retinal vessels. The recommended range for PaO2 of the premature infant receiving O2 is 50 - 80 mm Hg.
While giving nitrous oxide/oxygen/desflurane anesthesia in the radiology suite, you notice the pressure gauge of your e-cylinder of nitrous oxide decline from 745 psi to 744 psi. The approximate amount of nitrous oxide remaining in the e-cylinder is:
Only when all of the liquid nitrous oxide in the e-cylinder has been consumed will the pressure gauge begin to decline. At this point, Boyle's Law applies and the remaining volume of gas in the cylinder is approximately 253 liters.
A 70-kg patient is found to have a serum sodium of 153 mEq/L. From this information it is estimated that the free water deficit in this patient is approximately:
The free water deficit can be estimated from the formula:
Deficit = [(Na / 140) - 1)] * (Kg x 0.6)
The most rapidly conducting fibers in the heart are in the:
The His-Purkinje system possesses the most rapidly conducting fibers in the heart.
In the figure of a gravid uterus shown below, placenta increta is best represented by:
(Make your selection by clicking on the appropriate area of the figure)
The placenta normally implants into the endometrium. Placenta increta occurs when the placenta implants into the myometrium, but not entirely through the myometrium.
The proper diameter and length of insertion of an uncuffed endotracheal tube for an 8-year-old patient is:
-6 mm diameter, 16 cm length
-6 mm diameter, 12 cm length
-4 mm diameter, 12 cm length
-7 mm diameter, 14 cm length
6 mm in diameter, 16 cm in length
Endotracheal tube diameter can be estimated by the formula: 4 + Age/4. Endotracheal length can be estimated by the formula: 12 + Age/2
Hypotonic crystalloid solutions include (Select 2):
-D5 0.225% saline
D5W, 0.45% saline
Normal saline, Ringer's lactate and D5 0.225 saline solutions are isotonic with the plasma. 3% saline solution is hypertonic.
As compared to the normal pressure volume loop (purple) the yellow pressure volume loop is indicative of:
In aortic valve insufficiency, the aortic valve does not close completely at the end of systolic ejection. As the ventricle relaxes during diastole, blood flows from the aorta back into the ventricle. Therefore, there is no true phase of isovolumetric relaxation. Once the mitral valve opens, filling occurs from the left atrium, however, blood continues to flow from the aorta into the ventricle throughout diastole because aortic pressure is higher than ventricular. This greatly enhances ventricular filling so that end-diastolic volume is increased as shown in the pressure-volume loop.
During the administration of retrograde cardioplegia solution, the solution is administered through the:
-aortic cannula, proximal to the cross clamp
-superior vena cava cannula
-left and right coronary arteries
In the retrograde approach to cardioplegia administration, the cannula is placed into the right atrium and advanced into the coronary sinus. The solution is then administered in a retrograde fashion through the veins. This approach protects the myocardium that is distal to any coronary artery obstructions.
A patient with a history of hypertrophic obstructive cardiomyopathy is scheduled for a mastectomy. Intraoperative anesthetic management in this patient should include: (Select 2):
-peroperative diuretic therapy to reduce preload
-intraoperative vasodilator treat hypertensive episodes
-the use of inotropic agents to treat hypotensive episodes
-the use of esmolol to treat hypertensive episodes
-the use of phenylephrine to treat hypotensive episodes
-preoperative treatment with digitalis to reduce the incidence of arrhythmias
the use of esmolol to treat hypertensive episodes, the use of phenylephrine to treat hypotensive episodes
Hypertrophic obstructive cardiomyopathy (HOCM) is a common inherited disorder affecting about 1:500 patients. Factors that cause a reduction in left intraventricular volume result in an increase in left-ventricular-outflow tract obstruction. As a result, inotropic agents and reductions in preload or afterload should be avoided.
The device shown below analyzes delivered and end-tidal gas through:
Mass spectrometry ionizes gas molecules and passes them through a magnetic field. The gas molecules with the lowest mass-to-charge-ratio are easily deflected by the magnetic field and collected by an ion detector. Ionized gas molecules with higher mass-to-charge ratios are deflected less by the magnetic field and detected by other ion detectors.
Contributors to physiologic shunting include the:
Thebesian veins, bronchial veins, pleural veins
Thebesian, bronchial and pleural venous flows all allow desaturated venous blood to enter the left side of the heart and contribute to physiologic shunting.
An 80-year-old patient presents to the OR for phacoemulsification of cataract with IOL implant to be performed with topical anesthesia and conscious sedation. His medical history is remarkable for HTN and paralysis agitans (Parkinson's disease). Despite levodopa therapy, the patient exhibits a moderate tremor of the head. Which of the following agents may be beneficial for the conscious sedation of this patient?:
Paralysis Agitans (Parkinson's disease) is a degenerative disease of the CNS characterized by loss of dopaminergic fibers present in the basal ganglia of the brain. As a result, there is a depletion of dopamine in the basal ganglia which results in a diminished inhibition of the extrapyramidal motor system and an unopposed action of acetylcholine. One of the manifestations of this disease is rhythmic resting tremors. Mainstay of treatment for these patients is replacement of dopamine and suppression of neuronal effects of acetylcholine. Diphenhydramine, a central anticholinergic, is a useful sedative for these patients because it may diminish tremor. Although propofol and midazolam may be used in these patients, neither will suppress tremor. Droperidol is contraindicated for use as it antagonizes the effect of dopamine.
The purpose of the check valve in the yoke of the oxygen e-cylinder is to: (Select 3)
-prevent oxygen from entering the e-cylinders of nitrous oxide
-allow the exchange of an empty e-clyinder while a second e-cylinder is in use
-prevent oxygen from the e-cylinder from entering the oxygen hospital pipeline
-prevent cross-filling of oxygen e-cylinder
-allow the preferential use of pipeline oxygen if the e-cylinder is left open
-prevent loss of gas to the atmosphere if only one e-cylinder is present
prevent cross-filling of oxygen e-cylinders, allow the exchange of an empty e-cylinder while a second e-cylinder is in use, prevent loss of gas to the atmosphere if only one e-cylinder is present
The check valves on the yokes of the oxygen e-cylinders prevent gas leak if only one tank of oxygen is connected to a double-yoked system. In addition the check valves prevent cross-filling of oxygen tanks and allow for the exchange of an empty tank while a second is in use.
Which of the following statements is true regarding the central nervous system in the elderly patient?
-Larger doses of local anesthesia for epidural anesthesia are required 2nd to an enlarged epidural space
-the blood-brain barrier becomes increasingly permeable with aging
-Aging can lead to an approximate 50% decease in the ventilatory response to hypercapnia
-Brain size remains unchanged during the aging process
Aging can lead to an approximate 50% decrease in the ventilatory response to hypercapnia
Aging leads to an approximate 50% decrease in the ventilatory response to hypercapnia and an even greater effect in the response to hypoxia, especially at night. The blood brain barrier remains largely intact in the elderly, but can become disrupted by acute hypertension, disease, tumor, and ischemia. Segmental requirements for local anesthesia are reduced in the elderly secondary to decrease in the size of the epidural and interforaminal spaces.
After placement of a retrobulbar block, the patient demonstrates a dense motor block with a palpable increase in intraocular pressure and proptosis. This is most likely secondary to:
-an introacular injection
-an intravascular injection
-a retrobulbar hemorrhage
-a normal block with 2% lidocaine
Signs of retrobulbar hemorrhage include a dense motor block, proptosis, closing of the lid and a palpable increase in the IOP.
Your patient arrives to the OR for a triple arthrodesis of the right ankle under GETA. Past medical history is remarkable for rheumatoid arthritis, obesity, and GERD. Current medications include prednisone, gold salts, and omeprazole. Upon evaluation of her airway, you note that she is a Mallampati Class III with limited cervical and TMJ mobility. Your plan for airway management should include:
-use of a Bullard laryngoscope
-awake fibrotic intubation
-RSI with a McCoy flex-tip blade
-Fast-trach intubating LMA
awake fiberoptic intubation
The safest method to secure the airway of a patient with advanced rheumatoid arthritis is an awake fiberoptic intubation. Cervical spine involvement may include atlanto-axial subluxation and flexion deformities. Extension of the C-spine may result in odontoid displacement causing impingement on the cervical spinal cord, medulla, or vertebral arteries. Acute subluxation with flexion of the neck may result in paralysis or sudden death.
A 45-year-old man is undergoing an open reduction and fixation of a right tibial fracture under general anesthesia with mechanical ventilation. The end-tidal carbon dioxide is 60 mmHg, the peak airway pressure is 15 cmH2O with a tidal volume of 850 ml and a rate of 9/min. The expiratory flowmeter shows an exhaled volume of 410 ml. The most likely cause of the elevated end-tidal carbon dioxide is:
-indaequate ventilatory rate
-improperly set I:E ratio
-incompetence of the ventilator pressure relief valve
-restrictive pulmonary disease
incompetence of the ventilator pressure relief valve
This patient is experiencing hypoventilation as evidenced by elevated end-tidal carbon dioxide and a diminished expiratory volume, despite an adequate tidal volume and ventilatory rate. Incompetence of the pressure relief valve can allow a fraction of the inhaled volume to escape to the scavenger, thereby reducing the tidal volume, causing inadequate minute ventilation.
Which of the following agents is indicated for bleeding prophylaxis in the patient with von Willebrand's disease?
Desmopressin, a synthetic analogue of antidiuretic hormone, greatly increases Factor VIII activity in patients with mild to moderate hemophilia and von Willebrand's disease. Doses of 0.3 - 0.5 mcg/kg administered before and soon after dental surgery have prevented abnormal bleeding in these patients.
The lead recommended to best monitor narrow-QRS-complex arrhythmias, particularly if the P wave is significant for diagnosis, is:
(Make your selection by clicking on the appropriate area of the figure):
Lead II is recommended for assessment of narrow-QRS-complex arrhythmias, particularly if the p wave is significant for diagnostic criteria, such as in atrial flutter, atrial fibrillation and junctional rhythms..
A 66-year-old patient is being ventilated after coronary artery bypass surgery. The airway pressure/time graph of the patient's ventilation is shown below. This pattern is consistent with:
-controlled ventilation with PEEP
-synchronized intermittent mandatory ventilation
synchronized intermittent mandatory ventilation
Synchronized intermittent mandatory ventilation (SIMV) allows patients to breathe spontaneously at any rate and tidal volume while a certain minute ventilation is provided by the ventilator. Theoretical advantages include continued use of respiratory muscles, lower mean airway pressure, lower mean intrathoracic pressure, prevention of respiratory alkalosis and improved patient-ventilator coordination.
The plasma half-life of adenosine after intravenous administration is:
The most appropriate agent to attenuate the initial cardiovascular response to electroconvulsive therapy is:
Generalized autonomic nervous system stimulation from ECT results in an initial 10 to 15 seconds of bradycardia and occasional asystole, followed by a more prominent sympathetic response of hypertension and tachycardia. The initial parasympathetic effect may be prevented by premedication with glycopyrrolate or atropine.
A 16-year-old patient with sickle cell disease is scheduled for a laparoscopic cholecystectomy. Anesthetic goals for the include:
-restricted fluid administration
-avoidance of Hgb concentrations above 11 g/dL
-the use of mild intraoperative hypothermia
-reduction of cardiac output with beta blockers
avoidance of Hgb concentrations above 11 g/dL
Anesthetic goals for the patient with sickle cell anemia include the avoidance of hypothermia or hyperthermia, the avoidance of acidosis, the avoidance of hypoxemia, hypotension or hypovolemia and an increased FiO2. Red cell sickling is promoted by desaturation and low-flow states. Transfusion should match surgical loss; however increasing the Hgb greater than 10 - 11 g/dL should be avoided.
Severe hepatocellular dysfunction is commonly represented by a decrease in:
Synthetic functions of the liver include the production of albumin. With severe hepatocellular dysfunction, albumin levels are decreased. Other laboratory abnormalities associated with sever liver disease include increases in bilirubin, aminotransferases (ALT, AST), and an increase in the prothrombin time.
During hypothermic cardiopulmonary bypass, a reduction of core temperature to 27o C results in a reduction in cerebral oxygen requirement of approximately:
The beneficial aspects of hypothermia include a reduced metabolic rate, improved myocardial protection, tissue and organ preservation, and reduced oxygen consumption. The cerebral metabolic requirement for oxygen is reduced by 6 - 7% for each degree C drop in body temperature. As a result, a 10o C drop in core temperature results in an approximate decline of 50% in cerebral metabolic oxygen demand.
A list of biophysical fetal monitoring changes is shown below. By dragging & reordering the selections in yellow, match the event with the corresponding fetal monitoring change.
Decrease Beat to Beat Variation
Cord Compression-Variable Deceleration
Placental Insufficiency-Late Deceleration
Head Compression-Early Deceleration
Epidural Analgesia-Decrease Beat to Beat Variation
Drugs, such as opioids, anticholinergics and local anethetics, administered to parturients may blunt or eliminate beat-to-beat variability. Early decelerations are thought to be caused by vagal stimulation secondary to compression of the fetal head. Late decelerations imply uteroplacental insufficiency. Variable decelerations are thought to be secondary to umbilical cord compression.
The most common cause of heparin resistance is:
-previous coumadin anticoagulation
-rapid hepatic breakdown of heparin
-previous use of NPH insulin
-antithrombin III deficiency
antithrombin III deficiency
When heparin complexes with antithrombin III, the anticoagulant activity of antithrombin III is enhanced 1000-fold. Inadequate levels of antithrombin III is the most common cause of heparin resistance and can be corrected with recombinant antithrombin III or FFP.
Concerning conventional pulse oximetry:
-carboxyhemoglobin causes a falsely low oximeter reading
-methomoglobin causes a falsely elevated oximeter reading
-fetal hemoglobin has little effect on the accuracy of the oximeter reading
-hyperbilirubinemia causes a falsely low oximeter reading
fetal hemoglobin has little effect on the accuracy of the oximeter reading
Conventional pulse oximetry uses two wavelengths of light and is this allows saturation levels to be detected for oxyhemoglobin and reduced hemoglobin. Carboxyhemoglobin causes a falsely elevated reading, while methemoglobin causes a reading that declines to about 85%. It has been shown the neither fetal hemoglobin nor hyperbilirubinemia significantly affect the accuracy of the oximeter readings.
A 52-year-old patient is scheduled for an aortic valve replacement for long-standing aortic insufficiency. Anesthetic management goals in this patient include:
-maintenance of beta blockade and a HR below 70 bpm
-use of phenylephrine to maintain adequate SVR
-maintenance of adequate preload
-aggressive preoperative diuretic therapy to reduce left ventricular wall tension
maintenance of adequate preload, mild vasodilation, modest tachycardia
The main goal is to avoid increased LV wall stress. Full, mildly vasodilated, and modestly tachycardic describe the optimal cardiovascular state for patients with aortic insufficiency.
A 65-year-old man arrives to the OR suite for a sigmoid colon resection. His past medical history is remarkable for hepatic transplant 10 years ago, mild hypertension, and TIAs. Current medications include metoprolol, nimodipine, and cyclosporine. Preoperatively, he has received a neomycin bowel prep and metoprolol. Which of the following medications should be used with caution in this patient?
Cyclosporine, an immunosuppressant, nimodipine, a calcium channel blocker, and neomycin, a polypeptide antibiotic, may all potentiate non-depolarizing muscle blockade. Other medications which may also potentiate NDMB are: aminoglycosides, lidocaine, procainamide, tetracycline, volatile agents, local anesthetics, magnesium sulfate, diuretics, and lithium.
In the diagram below, the ligamentum flavum is best depicted by:
Moving externally to internally, the ligaments encountered during lumbar puncture are: the supraspinous ligament (D), the intraspinous ligament (B) and the ligamentum flavum (C). The epidural space is found just anterior to the ligamentum flavum. The arachnoid membrane is depicted by (A).
Ventilatory parameters expected to be normal after initial lung expansion in the term neonate include:
-RR ~ 15-20 breath/min
-FRC ~ 70 ml
-minute ventilation ~ 400 ml/min
-tidal volume ~ 70-100 ml
FRC ~ 70 ml
After lung expansion, the FRC approximates 70 ml in the term newborn, and changes little over the first 6 days of life. The tidal volume varies between 10 and 30 ml, RR ranges from 30-60 breaths/min, and minute ventilation exceeds 500 ml.
A 43-year-old female with a history of myasthenia gravis is scheduled for a thymectomy. Factors suggesting postoperative ventilatory insufficiency include:
-disease duration of 2 years
-vital capacity of 450 mL
-negative inspiratory pressure of -28 H20
-pyridostigmine dose of 850 mcg per day
-history of chronic bronchitis
pyridostigmine dose of 850 mgs per day, history of chronic bronchitis
Factors suggesting postoperative ventilatory insufficiency in the myasthenic patient include disease duration of more than 6 years, concomitant pulmonary disease, negative inspiratory pressure
Of the following epidural opioids, the most delayed onset and longest duration of action is expected with:
By comparison, morphine has the most delayed onset and longest duration of action of any of the epidural opioids. Onset occurs in 23.5 (+/- 6) minutes and duration of action ranges from 12-24 hours.
The liver receives blood flow from two sources, the hepatic artery and the portal vein. The ratio of hepatic artery blood flow to portal vein blood flow is approximately:
The liver receives about 25% of the cardiac output. The hepatic artery delivers about 25% of the flow and the portal vein about 75% of the flow (1:3). However, although most of the blood flow comes from the portal vein, it supplies only 50% of the oxygen supply.
A list of pharmacologic characteristics of local anesthetics is shown below. By dragging & reordering the selections in yellow, match the local anesthetic with the corresponding pharmacologic characteristic.
Increase Protein Binding
Bupivacaine-Increased Protein Binding
Components of the circle system that contribute to the total dead space include the: (Select 3)
-adjustable pressure limiting valve
-carbon dioxide absorber
Y-connector, endotracheal tube, facemark
Only areas of the circuit that allow bi-directional flow will contribute to dead space. Therefore only circuit components distal (and including) the Y-connector will be dead space.
Components of the intermediate-pressure system of the anesthesia machine include the:
-cylinder pressure gauges
-oxygen pressure failure devices
flush valve, flowmeter valves, oxygen pressure-failure devices
The anesthesia machine is broadly divided into 3 pressure systems, high pressure, intermediate pressure and low pressure. High-pressure components are exposed to cylinder pressure and include the hanger yoke, yoke block, cylinder pressure gauges and cylinder regulators. Intermediate-pressure components are exposed to pipeline pressure and include the pipelines, ventilator power inlet, oxygen pressure-failure devices, flowmeter valves and flush valve. The low-pressure components include the flowmeter tubes, vaporizers and the common gas outlet.
Anesthetic management of the patient with carcinoid syndrome should include:
-use of morphine at the end of the case for pain control during emergence
-blood pressure support with ephedrine as required intraoperatively
-volume expansion to maintain adequate preload
-pretreatment with octreotide
-muscle relaxation with atracurium to avoid the need for hepatic or renal clearance of the muscle relaxant
pretreatment with octreotide, volume expansion to maintain adequate preload
The key to management of the patient with carcinoid syndrome is the avoidance of the release of vasoactive substances from the tumor. Swings in blood pressure, catecholamine administration, the use of drugs that release histamine and hypercapnea have been associated with serotonin release from the tumor. As a result of the high concentrations of serotonin returning to the right heart, right-sided valve disease and myocardial plaque have been found in patients with carcinoid syndrome. Hypotension is best managed with volume expansion and an alpha-receptor agonist, such as phenylephrine. Octreotide mimics the inhibitory action of somatostatin on the release of gastrointestinal hormones.
-is only useful for patients who are breathing spontaneously
-terminates inspiration when a set pressure has been achieved
-terminates inspiration when a set volume has been delivered
-causes a reduction in the tidal volume of spontaneously ventilating patients
is only useful for patients who are breathing spontaneously
Pressure-support ventilation is similar to pressure-controlled ventilation in that it is a pressure-targeted ventilation mode, but with a rate of zero. Thus, it is only useful for patients who are breathing spontaneously; there is no minimum ventilation.
During the delivery of an anesthetic to a patient with a history of type 2 diabetes mellitus, the blood glucose level is found to be 240 mg/dL. Benefits of intraoperative reduction of the glucose level control include: (Select 3):
-reduced incidence of cerebrovascular accident
-improved postoperative wound healing
-reduced incidence of wound infection
-reduced incidence of myocardial infarction
-improved fetal outcome in pregnant patients
reduced incidence of wound infection, improved postoperative wound healing, improved fetal outcome in pregnant patients
Careful perioperative blood glucose control (
In assessing the patient with acidosis, it is useful to calculate the anion gap. The anion gap:
-is a measurement of major plasma cations minus the major plasma anions
-is a mesurèrent of the major plasma anions minus the major plasma cations
-has a normal range between 17-24 mEq/L
-is decreased in lactic acidosis
is a measurement of the major plasma cations minus the major plasma anions
Anion Gap = [Na+] - ([Cl-] + [HCO3-]) 140 - (104 + 24) = 12 mEq/L (normal range 7 - 14 mEq/L)
The anion gap is increased during increased production of endogenous acids as seen with lactic acidosis.
The square wave assessment below:
indicates an optimally damped system
The square wave assessment is used to determine the adequacy of damping of invasive pressure measuring devices. By delivering a brief flush, a rapid increase and fall of the tracing should be seen with several following "bounces". If one block or less separates the bounces, the frequency response is optimal. If 1.5 to 2 blocks between bounces is present, the height of the second bounce should be less than one third of the height of the first bounce for optimal damping to be present. If > 2.5 blocks are present between bounces the circuit is overdamped. This tracing demonstrates bounces that are approximately 1 block apart and indicates optimal damping.
Smoking cessation 24 hours prior to surgery has been shown to:
-reduce the incidence of postop pulmonary complications
-enhance immune function
-increase intraoperative HR and BP
-returen carboxyhemoglobin levels to normal
return carboxyhemoglobin levels to normal
Patients should be instructed to stop smoking at least 12 - 48 hours prior to surgery. Short-term (12 hour) abstinence from tobacco reduces catecholamine levels, intraoperative heart rate and blood pressure. Short-term abstinence has been shown to allow carboxyhemoglobin levels to return to normal. Longer-term (4 - 8 weeks) periods of abstinence reduce the incidence of pulmonary complications.