Answer Key to Post Test found in CEN Exam Preparation Course Manual

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Answer Key to Post Test found in CEN Exam Preparation Course Manual

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CEN Manual – Answer Key to Post Test

•    Question # 1:  The correct answer is D
Rationale: Myxedema coma is caused by decreased thyroid levels which decreases metabolism.  Decreased metabolism will cause a drop in core body temperature but the decrease in metabolism also suppresses shivering.  Bradycardia, rather than tachycardia and hypoglycemia rather than hyperglycemia are associated with the decreased metabolic states of myxedema coma.  The decrease in respiratory rate and effort associated with myxedema coma is more likely to cause a respiratory acidosis rather than alkalosis. 
 
•    Question # 2: The correct answer is C
Rationale:  Artifact at the baseline on the electrocardiogram of a patient with an implanted pacemaker is most commonly associated with external electrical interference such as electrocautery or magnetic resonance imaging.  An exit block would appear as pacing spikes on the electrocardiogram without QRS complexes following the spikes.  Increased pacemaker output is not generally associated with implanted pacemakers and would not show changes on the electrocardiogram.  Failure of the pacemaker battery is more likely to cause the pacemaker to fail to pace (demonstrating pacing spikes not followed by QRS complexes) or to fail to sense (pacing spikes in or after QRS complexes). 
 
•    Question # 3: The correct answer is B
Rationale:  Lysergic acid diethylamide (LSD) is a sympathomimetic drug and causes stimulation of the sympathetic nervous system.  This would cause symptoms such as hypertension (rather than hypotension), tachycardia (rather than bradycardia), tachypnea, diaphoretic skin, elevated temperatures, mydriasis (rather than miosis) and agitation.  
 
•    Question # 4: The correct answer is D
Rationale:  The analgesic effects of hydromorphone (Dilaudid) take approximately 15 – 30 minutes to begin.  The peak effect of this drug occurs approximately 30 – 90 minutes after administration and the duration of action is 4 – 5 hours. 
 
•    Question # 5: The correct answer is C
Rationale:  The dose of phenytoin sodium (Dilantin) is not to exceed 50 mg/minute in the adult (and 25 mg/minute in the elderly because of decreased renal clearance.)  Higher doses can cause toxicities which can lead to depression of the heart rate and contractility and unwanted drops in the blood pressure. 

•    Question # 6: The correct answer is A
Rationale:  A pericardial tamponade, caused by a restrictive pericarditis, will decrease cardiac output.  A decreased cardiac output will cause metabolic acidosis because of decreased oxygen delivery to the tissue.  Acidosis is marked by a serum pH below 7.35 (for example, a serum pH of 7.26).  A serum pH of 7.30 is normal, and a serum pH of 7.43 ad 7.51 indicate alkalosis instead of acidosis.  A serum bicarbonate level of 16 mEq/L further validates a metabolic acidosis.  Serum bicarbonate is normally 22 to 26 mEq/L, metabolic acidosis causes serum bicarbonate to decrease below normal.  A carbon dioxide level of 44 mm Hg is within normal limits which is consistent with a metabolic acidosis. 
 
•    Question # 7: The correct answer is B
Rationale: Endometriosis frequently causes dysfunctional uterine bleeding (bleeding outside of menstruation.)  This bleeding is often accompanied by abdominal or back pain and is often exacerbated by activities such as sexual intercourse (dyspareunia).  Vaginal bleeding, as opposed to amenorrhea is associated with endometriosis and fevers are not a common finding with this condition.  Foul smelling brown-colored vaginal discharge is more likely associated with a vaginal infection rather than endometriosis.  Although back pain may be associated with endometriosis, radiation to the left or right scapula is not common (radiation of pain to the scapula is more commonly associated with cholecystitis). 
 
•    Question # 8: The correct answer is A
Rationale: Hypotension is commonly associated with right ventricular infarctions (secondary to parasympathetic stimulation and a decrease in left ventricular filling.)  Therefore one goal of treatment for right sided infarctions is an increase in the patient’s blood pressure.  Patient’s with right ventricular infarctions are more likely to be bradycardic than tachycardic, therefore an elevation rather than decrease in the pulse rate is desirable.  There is little need to manipulate the temperature of a patient experiencing a right ventricular infarction; therefore, this is not a goal of treatment.  The respiratory rate of a patient experiencing a right ventricular infarction does not usually decrease; therefore a goal of treatment would not be to increase that rate. 
 
•    Question # 9: The correct answer is A
Rationale: Venom absorption may be diminished by applying ice as soon as possible after a black widow spider bite.  This should be initiated as soon after the bite as possible for maximum effectiveness.  Although intravenous medication may be administered, the initiation of an intravenous line does not carry a high priority in this situation.  Similarly, oxygen is usually not routinely required following a black widow spider bite.  Compression dressings will not alter the course of a black widow spider sting and are not indicated. 
 
•    Question # 10: The correct answer is C
Rationale: Both pain (head and neck pain) and fever may be associated with viral meningitis and administration of antipyretics and analgesics are indicated when prescribed.  Intubation and anticonvulsants are considered on a case-by-case basis but are rarely required for viral meningitis.  Viral meningitis is not communicable and does not require initiation of airborne precautions.   
 
•    Question # 11: The correct answer is B
Rationale:  To determine the mean arterial pressure (the average pressure in the vascular system over the entire cardiac cycle), one must double the diastolic pressure then add the resultant figure to the systolic pressure.  This number is then divided by three.  By using this formula, the following mean arterial pressures are obtained: 
a) 144/66 mm Hg equates to a mean arterial pressure of 92 mm Hg b) 122/98 mm Hg equates to a mean arterial pressure of 106 mm Hg c) 160/76 mm Hg equates to a mean arterial pressure of 104 mm Hg d) 116/92 mm Hg equates to a mean arterial pressure of 100 mm Hg
 
•    Question # 12: The correct answer is C
Rationale:  A potential complication associated with the application of an occlusive dressing over top of an open pneumothorax is a tension pneumothorax.  Signs of a tension pneumothorax include increasing respiratory distress and circumoral cyanosis.  A tension pneumothorax would also cause obstructive shock leading to symptoms such as hypotension (rather than hypertension), jugular venous distension and tachycardia.  A tension pneumothorax would cause respiratory decompensation leading to a respiratory acidosis.  Respiratory acidosis causes a decreasing serum pH rather than an elevating serum pH.  If the open pneumothorax is on the right chest wall, the tension pneumothorax is more likely to develop in the right chest, forcing the trachea to deviate to the left not to the right. 

•    Question # 13: The correct answer is B
Rationale: Patient’s with Reye’s syndrome tend to have increased intracranial pressure and initiation of measures to reduce intracranial pressure, such as elevation of the head of the bed, should be undertaken.  Although maintenance of normal body temperature should be considered, aggressive cooling measures are not required.  Intravenous calcium and broad-spectrum antibiotics do not change the outcome of Reye’s syndrome and are not indicated for these patients.  
 
•    Question # 14: The correct answer is C
Rationale:  A Smith’s fracture is a fracture of the distal radius and ulna with dorsal displacement of the distal radius and ulna.  The most likely mechanism of injury which causes this fracture is falling forward, landing on the back of the hand.  Falling forward and landing on the front of the hand causes ventral displacement of the distal radius and ulna known as a Colle’s fracture.  A direct blow to the middle of the forearm is more likely to cause a fracture of the medial radius and/or ulna and a direct blow to the middle of the upper arm is most likely to cause a fracture of the humerus. 
 
•    Question # 15: The correct answer is C  
Rationale: Inflammation of the peritoneal cavity causes diffuse abdominal pain.  Any irritation of the peritoneum from activities such as coughing or ambulation is likely to increase the pain.  Interventions which reduce tension on the peritoneum, such as assuming the fetal position are likely to lead to pain relief.  Pain may be exacerbated by deep breathing and is unlikely to lead to pain relief.  Although patients with peritonitis may experience respiratory difficulties and require oxygen administration, this is unlikely to lead to pain relief. 
 
•    Question # 16: The correct answer is B
Rationale:  Costovetebral angle tenderness is pain in the area where the ribcage meets the vertebral column in the lower ribcage.  The best way to test for costovetebral angle tenderness is to gently tap with a closed fist on either side of the vertebral column over the kidneys.  Acute pain may indicate renal illnesses such as pyelonephritis.  Squeezing the ribcage laterally and asking the patient to raise his or her legs off the stretcher when lying flat does not provide adequate assessment for costovetebral angle tenderness.  Palpating the spinous processes is used to assess for vertebral injury after trauma but is unlikely to elicit pain associated with costovetebral angle tenderness. 
  
•    Question # 17: The correct answer is C
Rationale:  A central retinal artery occlusion is caused by a blood clot forming in one of the branches of the retinal artery.  The retina is sensitive to hypoxia and if the blood clot is not removed in a short period of time, permanent vision loss may occur.  Vasodilators like sublingual nitroglycerin may assist to vasodilate the retinal artery allowing the blood clot to mobilize from the retina and save the vision.  Other interventions which may be considered include breathing into a paper bag to elevate carbon dioxide levels (carbon dioxide is a vasodilator) or administering carbogen gas.  Nitroglycerin may relax the esophageal sphincter and worsen gastroesophageal reflux which in turn would exacerbate esophagitis, so nitroglycerin is not indicated for esophagitis.  Cluster headaches are known to be caused by vasodilation of blood vessels in the head; therefore, vasodilation secondary to sublingual nitroglycerin is not desirable for this condition.  Venacaval compression syndrome is caused by the gravid uterus pushing on the large blood vessels of the abdomen when a pregnant woman lies flat on her back.  Sublingual nitroglycerin will not relieve this condition; instead the patient should be positioned so she is not on her back. 
 
•    Question # 18: The correct answer is B
Rationale:  Skin helps to maintain a normal body temperature.  Because an abrasion causes the loss of skin, the patient is at risk for heat loss into the environment (especially with large abrasions) causing hypothermia.  Fat emboli are associated with long-bone fractures but are not associated with large abrasions.  Thrombocytosis, an elevated platelet count, is not associated with large abrasions.  Compartment syndrome is caused by pressure within a muscular compartment, such as edema in a muscle compartment or external pressure such as an elastic wrap around an area.  Although injuries associated with abrasions may increase the risk of compartment syndrome, the abrasion itself does not contribute to compartment syndrome. 
 
•    Question # 19: The correct answer is C
Rationale:  When collecting clothing which may contain evidence, two sheets should be placed on the floor.  The lower sheet is meant to protect the top sheet from contamination on the floor.  The top sheet is meant to collect any evidence which may fall off of the clothing when it is removed.  At the completion of the resuscitation, each piece of clothing should be placed in a separate paper bag and the top sheet should be folded in on itself to preserve evidence which may be on it.  The top sheet should then be placed in a separate paper bag from the rest of the clothing to prevent evidence from the clothing from becoming intertwined with evidence on the sheet.  The lower sheet does not need to be given to law enforcement; it can be discarded in the hospital laundry. 
 
•    Question # 20: The correct answer is B
Rationale:  Hyporesonance is associated with consolidation in the underlying lung tissue.  The only condition listed which creates consolidation is pneumonia.  Asthma, emphysema and a pneumothorax would all cause accumulation of air in the chest causing hyperresonance as opposed to hyporesonance. 
 
•    Question # 21: The correct answer is A
Rationale:  Depression of the respiratory rate and blood pressure are potential unwanted side effects associated with Fosphenytion sodium (Cerebyx), therefore the respiratory rate and blood pressure should be carefully monitored during administration.  Atrial fibrillation, general erythema and changes in clotting measured by the international normalized ratio (INR) are generally not associated with the administration of Fosphenyation sodium. 
 
•    Question # 22: The correct answer is A
Rationale:  Albumin is important in maintaining osmolality and fluid balances in the body.  Decreased albumin causes fluid to leak into the extravascular compartment leading to edema.  Because albumin is produced by the liver, decreased albumin levels are frequently associated with liver failure.  Swelling of the liver causes portal hypertension and this hypertension, in addition to decreased serum osmolality causes fluid to leak into the abdomen causing ascites.  Liver insufficiency, which will cause ascites, is more likely to cause elevated ammonia, as opposed to decreased ammonia because the liver cannot no longer properly process ammonia.  Alanine transaminase (a liver enzyme) is likely to elevate with liver problems rather than decrease.  Ascites is not associated with an elevated white blood cell count. 
 
•    Question # 23: The correct answer is A
Rationale:  Delirium is caused by physiological disorders such as metabolic disorders, drug or alcohol withdrawal or heavy metal toxicities.  The causative disorder will often lead to a reduced level of consciousness if not aggressively treated.  Although alertness may be altered in patients with dementia (labile) or depression (flat), neither of these conditions is likely to alter the level of consciousness.  Similarly, schizophrenia does not cause a decreased level of consciousness. 
  
•    Question # 24: The correct answer is B
Rationale: Disseminated intravascular coagulation (DIC)is marked by a consumption of clotting factors such as platelets and fibrinogen.  Treatment may involve replacement of those factors, therefore an increase in platelets would be one hallmark of successful treatment.  Abnormal clotting associated with DIC causes metabolic acidosis, therefore decreasing serum pH levels are associated with worsening coagulopathies rather than effective treatment for DIC.  D-Dimer levels are associated the presence of blood clots.  The development of blood clots indicates worsening coagulopathies rather than effective treatment.  Coagulopathies cause bleeding which would potentially decrease hematocrit levels.  Therefore decreasing hematocrit levels are more likely associated with worsening coagulopathies rather than effective treatment. 
 
•    Question # 25: The correct answer is C
Rationale:  The base excess is unlikely to be altered in a patient with uncompensated respiratory alkalosis.  Normal base excess levels are between -2 and +2, therefore a base excess of +1 is normal and would be associated with uncompensated respiratory alkalosis.  Base excess levels less than -2 are more likely associated with metabolic acidosis and base excess levels above +2 are more likely associated with metabolic alkalosis.