CEN practice test questions and answers with solutions 2025

Preload refers to: a. The volume of blood entering the left side of the heart b. The volume of blood entering the right side of the heart c. The pressure in the venous system that the heart must overcome to pump the blood d. The pressure in the arterial system that the heart must overcome to pump the blood - ANSWER b. The volume of blood entering the right side of the heart Preload is the volume of blood that enters the right side of the heart. This volume stretches the fibers in the heart prior to contraction. Preload is commonly measured as atrial pressure. The patient is brought to the ED with an anterior ST-elevation myocardial infarction (STEMI). You are assessing him for possible administration of fibrinolytics. An absolute contraindication for this treatment is: a. The patient's pain is not relieved by medications. b. Symptoms began 36 hours before arrival. c. The patient has received aspirin in the last 2 hours. d. The patient had a previous MI 6 years ago. - ANSWER b. Symptoms began 36 hours before arrival. Fibrinolytic therapy is generally NOT recommended for patients whose symptoms began more than 12 hours before arrival. Fibrinolytics should not be given if the onset of symptoms was more than 24 hours before arrival UNLESS a posterior MI is diagnosed. In this case, the MI was anterior. The team is performing CPR on a patient. The rhythm that will respond to an electrical shock is: a. Asystole b. PEA c. Ventricular fibrillation d. SVT - ANSWER c. Ventricular fibrillation Ventricular fibrillation and pulseless ventricular tachycardia are the two rhythms that are considered to be "shockable" cardiac arrest rhythms. Although asystole and PEA are cardiac arrest rhythms, they will not respond to electrical shock. When suctioning during a cardiac arrest, suctioning should be limited to which of the following? a. Less than 5 seconds b. Less than 10 seconds c. Less than 20 seconds d. Less than 30 seconds - ANSWER b. Less than 10 seconds According to the 2010 BLS and ACLS guidelines, suctioning for longer than 10 seconds may result in pulling too much oxygen out of the airways resulting in hypoxemia. Possible causes of cardiac arrest include all of the following EXCEPT: a. Hypervolemia b. Hypoxia c. Hypokalemia d. Tension Pneumothorax - ANSWER a. Hypervolemia Common causes of cardiac arrest are known as the H's and T's and include: hypovolemia (NOT hypervolemia), hypoxia, hydrogen ion excess (acidosis), hypo or hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, and thrombosis (pulmonary or coronary). Correction of these causes can often reverse a cardiac arrest. You are providing ventilations using a Bag-mask device. Suddenly, you do not see the patient's chest rise with the ventilation. You reposition the patient to ensure an open airway. When you attempt to ventilate, you do not see his chest rise. The most likely cause of this is: