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MISSED QUESTIONS ON CCRN PRACTICE
EXAMS WITH ACCURATE ANSWERS
- A 29-year-old woman has been a patient in the critical care unit for 2 weeks with acute tubular necrosis (ATN) as a result of crush injuries experienced in a motor vehicle collision. She was normotensive on admission. What would be the most common explanation for her ATN? A. Rhabdomyolysis B. Hemorrhage C. Creatinine release D. Cardiac dysrhythmias correct answer A The most common cause for ATN in a normotensive patient who has experienced crush injuries is rhabdomyolysis with resultant myoglobinuria. Rhabdomyolysis is acute muscle destruction and is associated with myoglobinuria. Myoglobin released from muscle cells may cause acute kidney injury by having a direct toxic effect on tubule epithelial cells or inducing intratubular cast formation.
- A 48-year-old male patient with a history of inferior myocardial infarction (MI) is admitted with an acute anterolateral MI. He is tachycardic and hypotensive. Cardiac index is 1.9 L/min/m2. Pulmonary artery occlusive pressure (PAOP) is 20 mm Hg, and systemic vascular resistance (SVR) is 2000 dynes/sec/cm-5. Despite emergent percutaneous transluminal coronary angioplasty, Q waves develop, and cardiogenic shock continues. The patient remains significantly hypotensive despite dobutamine infusion. An intra-aortic balloon pump (IABP) is inserted via
his left femoral artery. Which of the following is the primary functions of the IABP in this patient? A. Decrease afterload and improve coronary artery perfusion. B. Decrease preload and myocardial oxygen consumption. C. Decrease preload and afterload. D. Decrease afterload and increase cardiac contractility. correct answer A The primary effects of IABP are decreased afterload and improved coronary artery perfusion pressure. IABP does not directly affect preload, and it does not directly increase cardiac contractility.
- A 57-year-old man was admitted to the critical care unit with a diagnosis of anteroseptal myocardial infarction. A pulmonary artery catheter was inserted, and initial readings were within normal limits. Vital signs were blood pressure 140/92 mm Hg, heart rate 110 beats/min and regular, and respiratory rate 24 breaths/min. Breath sounds are equal and clear to auscultation. Three hours after admission, the patient becomes restless with cool, pale skin. Vital signs are now blood pressure 110/72 mm Hg, heart rate 120 beats/min, and respiratory rate 28 breaths/min and labored. Breath sounds are still equal, but crackles are audible at the lung bases bilaterally. The patient is given furosemide (Lasix) at 8 am. At 9 am, the pulmonary artery occlusive pressure (PAOP) drops to 8 mm Hg with a drop in the blood pressure. Which of the following would be the most appropriate intervention at this time?
- A postoperative cardiac surgery patient's blood pressure suddenly drops to 70 mm Hg palpable, with a loss of the a wave in the pulmonary artery occlusion pressure (PAOP) waveform. What change in his cardiac rhythm would cause this change in his PAOP waveform? A. Sinus tachycardia B. Sinus dysrhythmia C. Atrial tachycardia D. Atrial fibrillation correct answer C The loss of the a wave equals the loss of atrial contraction, which is certain in atrial fibrillation.
- Increasing the driving pressure of oxygen increases blood oxygenation. Driving pressure of oxygen is affected by which two factors? A. Compliance and resistance B. Oxygen concentration and barometric pressure C. Hemoglobin and arterial oxygen saturation (SaO2) D. Cardiac output and systemic vascular resistance correct answer B
The driving pressure of oxygen across the alveolar-capillary membrane is affected by the concentration of the gas (FiO2) and the barometric pressure (760 mm Hg at sea level). Therefore blood oxygenation is increased by increasing the FiO2 or by increasing the pressure, such as with a hyperbaric chamber or the addition of continuous positive airway pressure or positive end-expiratory pressure.Compliance and resistance affect the work of breathing. Hemoglobin and SaO2 affect the CaO2 (content of oxygen in the arterial blood). Cardiac output and systemic vascular resistance affect blood pressure.
- Which is a normal oxygen consumption index (VO2I)? A. Approximately 50 ml/min/m B. Approximately 100 ml/min/m C. Approximately 150 ml/min/m D. Approximately 200 ml/min/m2 correct answer C Normal arterial oxygen saturation is 100%, and normal venous oxygen saturation is 75%. The tissues used 25%. The normal arterial oxygen content is 20 ml/dl, and normal venous oxygen content is 15 ml/dl. The tissues used 25%. The normal oxygen delivery (DO2) is 1000 ml/min, and normal VO2 is 250 ml/min. The tissues used 25%. The normal DO2I is 600 ml/min/m2, so consider what is 25% of 600 ml/min/m2? The normal VO2I is 150 ml/min/m2.
Intra-alveolar fluid and damage to type II pneumocytes result in a decrease in the amount and effectiveness of surfactant. This causes alveolar collapse (decreased functional residual capacity), pulmonary edema, decrease in lung compliance, and massive intrapulmonary shunt. Intrapulmonary shunt causes severe hypoxemia that is refractory to oxygen therapy.
- Which of the following is useful in the elimination of significant variations in practice? A. Systematic reviews B. Clinical practice guidelines C. Meta-analyses D. Meta-synthesis correct answer B Clinical practice guidelines are translation of the best scientific evidence to recommendations for practice. Their primary purpose is to use evidence summaries for translation of best evidence to best practices for consistency in the provision of evidence-based practice.
- Which of the following statements about colloids is correct? A. They are classified as hypotonic, hypertonic, and isotonic. B.
They increase interstitial and intracellular volume. C. They increase intravascular colloidal oncotic pressure. D. They are the first-line treatment in fluid resuscitation. correct answer C Colloids increase intravascular colloidal oncotic pressure and pull fluid from the interstitial space into the intravascular space. Current research has not found a benefit of colloids over crystalloids in fluid resuscitation, and colloids are much more expensive.
- Which of the following statements regarding amiodarone is incorrect? A. It may be administered to patients with ventricular tachycardia and left ventricular dysfunction. B. It may be used with atrial tachycardia that is unresponsive to adenosine. C. It may be used to treat torsades de pointes. D. It may prolong the QT interval. correct answer C Torsades de pointes is polymorphic ventricular tachycardia that is preceded by a prolonged QT. Amiodarone may cause a prolonged QT and would not be indicated in torsades de pointes. Magnesium is the first-line drug for torsades de pointes.
Increased lipase correct answer D Lipase and amylase are elevated in pancreatitis. Alkaline phosphatase and bilirubin would be elevated because of the biliary disease. Potassium would be decreased because of vomiting. Albumin is decreased because of increased capillary permeability and protein leakage. Calcium is decreased because of fat necrosis and precipitation of calcium salts. *A 45-year-old man is admitted with acute epigastric pain that radiates to his back. He says that he has been vomiting continuously for 12 hours and that the pain has been worsening. His social history includes the information that he drinks about two 6-packs of beer each night. He has dry, cracked lips and poor skin turgor. His abdomen is distended and tender. He is restless and agitated. Vital signs are blood pressure of 90/60 mm Hg, heart rate of 135 beats/min, and respiratory rate of 28 breaths/min. While assessing the patient's blood pressure, the nurse notes spasm of the patient's hand. Which of the following does this indicate? A. Hyponatremia related to overhydration B. Hypocalcemia related to fat necrosis and precipitation of calcium C. Metabolic acidosis related to hypoperfusion D. Hypoalbuminemia related to protein loss correct answer B This is a description of Trousseau sign, an indication of hypocalcemia or hypomagnesemia. Calcium levels become low in acute pancreatitis because of fat necrosis and precipitation of calcium.
*A 52-year-old man is admitted to the critical care unit with a diagnosis of an acute myocardial infarction (MI). His electrocardiogram shows ST segment elevation and T wave inversion in leads V2, V3, and V4. His history includes hypertension, 80 pack-years of smoking, chronic obstructive pulmonary disease (COPD), and hypercholesteremia. Which of the following prescriptions should be questioned? A. Metoprolol B. Aspirin C. Propranolol D. Heparin correct answer C Although β-blockers are important for prevention of extension and reinfarction with acute MI, COPD in the medical history contraindicates a noncardioselective β-blocker. Metoprolol is a cardioselective β-blocker that blocks β1 selectively. Other cardioselective β-blockers are acebutolol, atenolol, and esmolol. Propranolol is a noncardioselective β-blocker that blocks β1 receptors and β receptors. The blockage of β2 receptors (vasodilation and bronchodilation) in a patient with COPD may cause bronchospasm. Aspirin and heparin are important in the prevention of reocclusion after fibrinolytic therapy. *A 52-year-old woman developed an epidural hematoma after being in a motor vehicle collision. She has had a craniotomy to evacuate the clot, and an intraventricular catheter was placed during surgery. While the nurse is monitoring
10 mEq/L. C. 15 mEq/L. D. 20 mEq/L. correct answer D The anion gap = (Na + K) - (Cl + HCO3). A normal anion gap is less than 15 mEq/L. An anion gap of greater than 15 mEq/L indicates that there are unmeasured acids (e.g., lactic acidosis, ketoacidosis, certain toxins, and accumulation of fixed acids resulting from renal failure). *A 55-year-old man is admitted to the critical care unit with a diagnosis of acute respiratory failure. The patient must be ventilated mechanically for 2 weeks. Initial liberation efforts are to be initiated tomorrow. Which of the following would improve the patient's chance for successful liberation from mechanical ventilation? A. High protein, high carbohydrate, low fat B. High protein, low carbohydrate, high fat C. Low protein, high carbohydrate, low fat D. Low protein, low carbohydrate, high fat correct answer B Digestion of carbohydrates produces more carbon dioxide than does digestion of proteins and fats. The diet should be high in protein and high in calories, but the calories should be in the form of fats rather than carbohydrates. Pulmocare brand enteral feeding is high in protein and fat and low in carbohydrates. The same
adjustment can be made if the patient is receiving parenteral feedings by decreasing the dextrose amount and increasing the amount of Intralipid. *A 60-year-old man is admitted with an acute anterior myocardial infarction. He undergoes a percutaneous coronary intervention but develops clinical indications of heart failure and cardiogenic shock. The physician prescribes dobutamine at 5 mcg/kg/min to be increased as necessary. His hemodynamic parameters are as follows: BP 80/60 mmHg RAP 8 mmHg PA 40/25 mmHg PAOP 22 mm Hg SVRI 2500 dynes/sec/cm-5/m CI 1.9 L/min/m VO2 56% Which of the following actions is appropriate, considering these hemodynamic parameters? A. Increase the dobutamine. B. Discontinue the dobutamine. C. Add dopamine (d). D. Add nitroprusside. correct answer A
Pleural friction rub correct answer D Fibrinolytic agents are indicated for massive and submassive pulmonary embolism. Unfortunately, patients with massive pulmonary embolism may not survive long enough for treatment with fibrinolytic agents. Hemodynamic consequences, refractory hypoxemia, and significant obstruction by arteriogram are the usual clinical indications for fibrinolytic agents. Pleural friction rub is an indication of pulmonary infarction and occurs 24 to 72 hours after the pulmonary embolism. This would be too late to reverse the hypoperfusion injury to the lung. *A patient arrived in the emergency department with complaints of chest pain. The 12-lead electrocardiogram shows ST segment elevation in leads V3 and V4. Occlusion of the affected coronary artery most likely would affect perfusion to which portion of the conduction system? A. Sinoatrial (SA) node B. Bachmann bundle C. Atrioventricular (AV) node D. Bundle of His correct answer D ST segment elevation in leads V3 and V4 indicates injury to the anterior wall, which would occur with occlusion of the left anterior descending (LAD) artery. In most persons, the SA node, Bachmann bundle, and AV node are supplied by the right coronary artery. The bundle of His is supplied by the left anterior descending artery. This is why an anterior myocardial infarction may cause type II second- degree AV block or third-degree AV heart block at the level of the bundle of His.
*A patient has a history of dilated cardiomyopathy and repeated admissions. This time, she is admitted with acute dyspnea and generalized edema. She has mitral regurgitation and insists on talking with the physician about surgery on her mitral valve. She tells the nurse that she believes that she will be much better and probably will not need a new heart after they give her a new mitral valve. Which of the following best describes her stage of death and dying? A. Anger B. Bargaining C. Denial D. Acceptance correct answer C She is denying the seriousness of the situation and wants to believe that the new mitral valve will eliminate the problem. *A patient is admitted to the emergency department with complaints of severe headache. She states that she has been out of her blood pressure pills for 3 weeks and cannot afford to buy more. Her blood pressure ranges from 250/128 mm Hg to 200/110 mm Hg. Nitroprusside is being titrated, and the patient is receiving oxygen by nasal cannula. Which of the following describes the appropriate drug therapy and goal for this patient? A. Diuretics to decrease preload B. Arterial vasodilators to decrease afterload
Parasympathetic nervous system stimulation C. Injury to the hypothalamus D. Focal injury to cerebral hemispheres correct answer A Think of neurogenic shock as no α and no β caused loss of sympathetic nervous system innervation. Lack of α causes loss of vascular tone and a decrease in systemic vascular resistance. Lack of β causes decrease in heart rate, contractility, and conductivity. Remember: Neurogenic shock equals no α, no β. *If a patient with a normal pH and temperature has a PaO2 of 60 mm Hg, his arterial oxygen saturation (SaO2) is closest to which of the following values? A. 75% B. 90% C. 95% D. 99% correct answer B With a normal oxyhemoglobin dissociation curve, the SaO2 will be approximately 99% with a PaO2 of 100 mm Hg 95% with a PaO2 of 80 mm Hg
90% with a PaO2 of 60 mm Hg 75% with a PaO2 of 40 mm Hg. *In addition to the analgesic effects, morphine also causes which of the following physiologic effects? A. Dilates the coronary arteries. B. Increases contractility. C. Decreases preload. D. Decreases afterload. correct answer C Morphine is a venous vasodilator. Dilation of veins causes a decrease in preload. Morphine does not cause a significant effect on arteries, so it does not decrease afterload directly or dilate coronary arteries. However, by decreasing pain and decreasing catecholamine release, afterload may be decreased. Morphine has no positive inotropic qualities. *Oxygen delivery (DO2) is the product of which of the following? A. PaO2, hemoglobin, mean arterial pressure B. SaO2, hemoglobin, cardiac output C. SvO2, cardiac index, SaO
