Simulation Exam 6 Flashcards
Which of the following organs is most responsible for the initial rapid uptake of local anesthetics following intravenous injection?
The initial rapid uptake of local anesthetics is due to uptake by the highly perfused organs (brain, heart, liver, kidneys, and lungs). The lungs in particular extract large amounts of local anesthetics and reduce the plasma concentration of the local anesthetic quickly. Muscle and gut tissue exhibit moderate perfusion and contribute to the slower redistribution of local anesthetics.
In adults, the dura extends from the foramen magnum to:
In adults, the dura space extends from the foramen magnum to S2. The spinal cord itself extends to L1 in adults and L3 in children.
Which of the following has the greatest effect on the block height of a spinal anesthetic?
Intra-abdominal pressure
Factors such as patient height, age, BMI, and length of the vertebral column don’t affect the spread of a spinal anesthetic. Pregnancy, obesity, and increased intra-abdominal pressure increase the height of sensory block, however. It is believed that these conditions increase the block height because of a lower lumbar CSF volume.
A 41 year-old female is five foot nine inches tall and weighs 220 pounds. You would classify this patient as
Obesity Class I
To answer this question, you must first determine the patients body mass index (BMI) which is the weight in kilograms divided by the height in meters squared. To obtain the weight in kilograms, divide the weight in pounds by 2.2. The answer is 100 kilograms. Next, multiply the height in inches (69) by 0.0254 to convert it to meters. Take this result (1.75m) and square it to arrive at 3.0 meters squared. Divide the weight in kilograms (100) by 3.0 meters squared to arrive at a BMI of 33.3. The scale for BMI is as follows: A BMI < 18.5 = Underweight, 18.5-24.9 = Normal, 25-29.9 = Overweight, 30-34.9 = Obesity Class I, 35-39.9 = Obesity Class II, > 40 = Obesity Class III (morbid obesity)
Which of the following statements regarding the Bain circuit is true?
It utilizes a countercurrent exchange to warm the fresh gas
The Bain circuit is a modification of the Mapleson D circuit utilizing a coaxial system in which the fresh gas hose lies within the corrugated tubing through which exhaled gas flows. The exhaled gas passes in the opposite direction of the fresh gas, establishing a countercurrent, which helps warm the inspired gas. It requires a fresh gas flow of 1-2 times that of the minute ventilation to prevent rebreathing. The exhalation tubing should provide a volume larger than the tidal volume to prevent rebreathing when using an Ayres T-piece, not a Bain circuit.
Which of the following laboratory results is associated with damage to the renal tubules?
Increased urinary sodium excretion
Urinary sodium > 40 mEq/L is associated with damage to the renal tubules. Orthostatic proteinuria occurs in 5-10% of the population and is not associated with renal damage. Glucosuria is associated with increased serum glucose levels. Decreased hematocrit is associated with anemia and increased intravascular fluid volume.
A patient undergoing hysteroscopy is placed in lithotomy position with medially-placed strap supports. In the recovery area, the patient complains of numbness and tingling along the medial aspect of the calves. You suspect there could be damage to the
Although lithotomy position can result in damage to any of these nerves, this patient’s presentation is most consistent with damage to the saphenous nerve, which innervates the medial calf. This is most likely to occur with medially placed strap supports. Extreme flexion at the thigh can result in injury to the sciatic, obturator, and femoral nerves while injury to the common peroneal nerve can occur if the lateral thigh is allowed to rest on strap supports.
Which of the following positioning techniques indicates the anesthetist’s understanding of appropriate methods of protecting the ulnar nerve from position-related injury?
Both hands are positioned supine
The ulnar nerve is most at risk for compression damage where it passes under the medial epicondyle. Pronation of the hand positions the ulnar nerve directly against the table surface, making it a high-risk position. Supinating the hand shifts the ulnar nerve above the table surface and allows the olecranon to bear the weight of the arm. Tucking the arms at the sides can still leave the ulnar nerves at risk and padding should be placed around the elbows to protect the ulnar nerve. Abducting the arms less than 90 degrees provides a degree of protection for stretch injury to the brachial plexus, but has little bearing on the ulnar nerve.
A patient with von Willebrand disease is experiencing continued bleeding at the site of his surgical incision despite treatment with DDAVP. The next treatment you would recommend for this patient is:
Cryoprecipitate
Patients with von Willebrand disease should be given desmopressin which increases factor VIII-vWF complex and improves coagulation. If desmopressin doesn’t produce a sufficient response, cryoprecipitate should be considered.
All of the following are potential systemic manifestations of rheumatoid arthritis except:
Catecholamine excess
Unlike osteoarthritis, rheumatoid arthritis is associated with numerous systemic abnormalities including pericardial thickening and effusion, myocarditis, coronary arteritis, conduction defects, vasculitis, aortic regurgitation, pleural effusion, interstitial pulmonary fibrosis, anemia, and thrombocytopenia. The use of immunosuppressive treatment drugs leads to atrophy of the skin. Platelet dysfunction can occur secondary to the use of aspirin and adrenal insufficiency (resulting in catecholamine depletion, not excess) results from chronic corticosteroid therapy.
Which of the following statements regarding eutectic mixture of local anesthetic (EMLA) cream is true?
the depth of analgesia is usually 3-5 mm
EMLA cream consists of a 1:1 mixture of 2.5 percent lidocaine and 2.5 percent prilocaine in an oil-in-water emulsion. It requires a contact time of at least one hour under an occlusive dressing, reaches a depth of analgesia of about 3-5 mm, and has a duration of about 1-2 hours.
Injection of 3 mL of 2% lidocaine bilaterally 1 centimeter below each greater cornu of the hyoid
anesthetizes the airway below the epiglottitis
Injection of 3 mL of 2% lidocaine bilaterally 1 cm below each greater cornu of the hyoid is a superior laryngeal nerve block which anesthetizes the airway below the epiglottis as well as a portion of the epiglottis itself. A transtracheal block is performed by injecting 3-5 mL of 2% lidocaine through a needle penetrating the cricothyroid membrane into the trachea. The lingual and pharyngeal branches of the glossopharyngeal nerve are blocked by infiltrating local anesthetic into the base of the palatoglossal arch.
Select all of the sites where arginine vasopressin exerts its effects (select two)
Arginine vasopressin exerts its primary effects on the renal-collecting ducts in the nephron where it encourages passive water reabsorption. It also acts upon vascular smooth muscle and cardiac myocytes. It also causes dramatic vasoconstriction and has an inotropic effect. The endogenous form of vasopressin is released from the posterior pituitary gland.
Which substance enhances the sensitivity of nerve endings to painful stimuli but does not directly excite them?
substance P
Histamine, bradykinin, potassium, serotonin, acetylcholine, acids, and proteolytic enzymes are direct chemical stimulators. Substance P and prostaglandins don’t directly stimulate the nerve endings, but they increase their sensitivity to other painful stimuli.
Which of the following statements regarding the use of an automatic implantable cardioverter defibrillator (AICD) is false?
Unipolar cautery will not cause an AICD to fire
Unipolar cautery may produce electrical interference that may be interpreted as a ventricular dysrhythmia by an AICD. This could potentially trigger a defibrillation pulse. It is best to consult with someone who has experience with the specific device prior to surgery or place a magnet over the device to temporarily disable it.
