ITE 2009 A Flashcards
- A 67 year old man is undergoing total hip replacement under general anesthesia. He had a permanent endocardial VVI pacemaker placed 2 years ago for complete heart block, and since arrival in the operating room has been paced continuously. Use of the electrocautery causes the pacemaker to malfunction intermittently. The most appropriate management is to
A. tape a magnet over the pacemaker generator and convert to asynchronous mode
B. do nothing since the pacemaker is programmed to deal with this circumstance
C. stop the surgeon from using the electrocautery
D. limit the surgeon to 10sec/min electrocautery bursts
E. place the electrocautery indifferent lead as close as possible to the pacemaker
- A
- Peak airway pressure increases from 25 to 50 cmH20 when beginning right endobronchial ventilation with a right double-lumen tube. The most likely explanation for this increase is
A. failure to decrease tidal volume
B. inadvertent intubation of the left mainstem bronchus
C. intrinsic resistance of small endobronchial lumina
D. obstruction of the orifice of the right upper lobe
E. overinflation of the bronchial tube cuff
- E
3. During enflurane anesthesia for colectomy in a 75 year old man with sepsis, urine output decreases to 10 ml/hr. Heart rate is 120 bpm, blood pressure is 100/50 mmHg, central venous pressure is 10 mmHg, and pulmonary artery occlusion pressure is 15 mmHg. The most appropriate management at this time is to A. measure cardiac output B. increase fluid administration C. infuse dopamine D. administer propranolol E. switch from enflurane to isoflurane
- A
4. Hypothermia to 29 Celcius will decrease A. hematocrit B. plasma fibrinogen concentration C. plasma pH D. plasma protein concentration E. platelet function
- E
- A 15 year old previously healthy boy is scheduled for celiotomy to relieve an acute intestinal obstruction. A rapid sequence induction is used. Anesthesia is maintained with a balanced technique including nitrous oxide and oxygen (5L:2L), meperidine, and pancuronium. Because of abdominal distention and the high pressure required for inflation of the lungs, a nasogastric tube is inserted. The abdomen remains distended, but compliance improves dramatically. At this time the patient is cyanotic, PaCO2 is 48 mmHg, PaCO2 is 52 mmHg, and pH is 7.29. Nitrous oxide is discontinued. The most important therapuetic measure is to
A. remove the nasogastric tube
B. insert a chest tube on the right side
C. withdraw the endotracheal tube 1 cm
D. deflate the cuff on the endotracheal tube
E. replace the endotracheal tube with one of larger internal diameter
- A
- In an unpremedicated, spontaneously breathing patient, an alveolar halthone concentration of 0.74% in oxygen is consistently associated with
A. absence of overt response to skin incision
B. constricted pupils
C. flaccidity of abdominal muscles
D. normal glomerular filtration rate
E. normal myocardial contractility
- B
7. Following a vaginal hysterectomy in the lithotomy position under general anesthesia, a patient has numbness of the lateral aspect of the left calf and medial half of the dorsum of the left foot. On physical examination she has footdrop and the toes cannot be extended. Which nerve is most likely to be involved? A. common peroneal nerve B. deep peroneal nerve C. posterior tibial nerve D. saphaneous nerve C. sciatic nerve
- A
- Pulmonary artery diastolic pressure increases acutely from 10 to 20 mmHg in a 28 year old man undergoing cervical laminectomy in the sitting position. The most appropriate first step in the management of this patient is to
A. administer furosemide
B. aspirate from the proximal port of the pulmonary artery catheter
C. inflate the balloon on the pulmonary artery catheter
D. place the patient in the left lateral decubitus position
E. start an infusion of nitroglycerin
8 B The most common complications associated with the surgical sitting position includes venous air embolism (VAE), paradoxical VAE, cardiovascular instability, pneumocephalus, subdural hematoma, peripheral neuropathy, and quadriplegia (quadriplegia is possibly caused by compression ischemia of the cervical spinal cord in patients with aerrant spinal cord blood supply). Venous air embolism (VAE) occurs when air is entrained into open veins int he presence of negative intraluminal pressures (i.e., negative with respect to atmospheric pressure).Significant VAE can result in reduced cardiac output and profound hypoxia. Current devices used to detect VAE include the TEE, Doppler ultrasound, pulmonary artery catheter, mass spectrometer (to monitor changes in Peco2 and Pen2), right atrial catheter, and esophageal stethescope (to listen for a “mill wheel” cardiac murmur). The most sensitive means of diagnosing VAE include TEE or precordial Doppler monitoring. Air in the pulmonary artery can increase pulmonary vascular resistance (PVR) and cause right heart strain and dysrhythmias. The general approach to treating VAE is to: (1) stop further air entrainment; (2) aspirate entrained air; (3) prevent expansion of existing air; and (4) support cardiovascular function. Cessation of subsequent air entrainment is achieved by flooding the surgical field with irrigation fluid. Additionally, non collapsible veins can be sealed using electrocautery, vessel ligation, or bone wax. Neck veins can be compressed as a means of increasing jugular venous pressure, which mitigates or prevents further air entry and helps localize the source of air. A multiorificed right atrial catheter, placed before the event, is the most effect means of aspirating VAE. In order to prevent expansion of the VAE, nitrous oxide is immediately discontinued. Cardiovascular function is supported using ionotropes, vasopressors, and IV fluids as indicated. Approximately 20% to 30% of humans have a probe patent foramen ovale. Initiation of PEEp may increase the risk of paradoxical embolism or decrease venous effluent from the calvarium, resulting in creased CBV and ICP.
9. During the first stage of labor, the pain of uterine contractions and cervical dilation is transmitted via the spinal cord segments A. T6 to L1 B. T6 to S5 C. T10 to L1 D. T10 to S1 E. T10 to S5
- C
- During use of the ventilator on an anesthesia machine, positive pressure is noted on the airway pressure gauge during exhalation. Positive end-expiratory pressure has not been purposefully added to the breathing circuit. Which of the following is the most likely cause?
A. closure of the pop-off valve in the circle system
B. excessive tidal volume settings on the ventilator
C. obstruction of the pressure relief valve on the scavenging system
D. overinflation of the endotracheal tube ballon
E. tension pneumothorax
- C
- Addition of 20 cmH20 positive end-expiratory pressure to a patient receiving controlled mechanical ventilation decreases cardiac output and left ventricular function by
A. increasing right ventricular preload
B. increasing right ventricular afterload
C. increasing left ventricular preload
D. increasing left ventricular afterload
E. producing myocardial ischemia
- B
- A 75 year old man is confused, restless and disoriented two days after an aortic aneurysm repair. Serum sodium concentration is 112 mEq/L, serum osmolality is low, and urine is hypertonic. The most appropriate treatment is
A. restriction of fluid intake
B. administration of isotonic saline solution
C. administration of hypertonic (3%) saline soludion
D. administration of spironolactone
E. infusion of mannitol 25g
- C The triad associated with cerebral salt-wasting syndrome consists of hyponatremia, volume contraction, and urine sodium concentrations inappropriately high for the given level of serum sodium. It is mainly seen in patients with SAH. A possible etiology may be release of brain natruiretic peptide, leading to excess urinary sodium excretion. It is treated with volume replacement, utilizing normal to hypertonic IV sodium chloride solution, but avoiding overly rapid serum sodium correction as this may result in central pontine mylenolysis. Cerebral salt wasting syndrome (usually hypovolemic) is difficult to differentiate from SIADH (usually normovolemic or mildly hypervolemic) because patients with SAH can have high ADH levels secondary to trauma, pain et. A definitive diagnosis requires demonstration of a negative Na balance over several days in the setting of ongoing hypovolemia or obtaining a 24 hour urine sodium sample. Clinically, the former is often not feasible because of competing interests for prophylaxis of treatment of cerebral vasospasm with moderate hypervolemia. In the setting of cerebral salt-wasting syndrome, the 24 hour sodium value is elevated. In contrast, hyponatremia associated with SIADH is due to renal retention of free water (rather than renal loss of sodium). Accordingly, the quantity of sodium collected over the 24 hour period and CVP should be relatively normal in SIADH patients.
- A 65-year-old man with essential hypertension well controlled around 140/90 mmHg with hydrochlorothiazide is scheduled for right colectomy for carcinoma. Preoperative EKG and all laboratory values are normal except for a hematocrit of 29% and serum potassium level of 3.2 mEq/L. Central venous pressure (CVP) measured from internal jugular catheter inserted before induction of anesthesia is 7 mmHg. Ten minutes after induction with thiopental 200 mg followed by enflurane 3% in nitrous oxide and oxygen (50% each), blood pressure decreases suddenly from 110/70 to 80/50 mmHg with heart rate unchanged at 78 bpm. CVP is now 20 mmHg and EKG demonstrates a midjunctional rhythm. After discontinuing enflurane, the most appropriate action would be
A. administer furosemide 20 mg intravenously
B. verify proper placement of the CVP catheter
C. administer atropine 0.4 mg intravenously
D. administer packed erthyrocytes 1 unit
E. administer potassium 20 mEq in 250 ml of intravenous fluid over 15 minutes
- C
- Halothane
A. has no effect on reflex hypoxic pulmonary vasoconstriction
B. protects the myocardium from beta-adrenergic stimulation
C. has a direct, negative chronotropic effect on the sinoatrial node
D. metabolites decrease renal concentrating ability
E. is unsafe for use with epinephrine containing local anesthetics
- C
