Oxygenation - Chapter 40 Flashcards
The structure that is responsible for returning oxygenated blood to the heart is the
- Pulmonary artery.
- Pulmonary vein.
- Superior vena cava.
- Inferior vena cava.
- Pulmonary vein.
Rationale:
The pulmonary vein carries oxygenated blood to the heart. The pulmonary artery carries deoxygenated blood from the heart to the lungs. Both venae cavae return blood to the right atrium of the heart.
Chemical receptors that stimulate inspiration are located in the
- Brain.
- Lungs.
- Aorta.
- Heart.
- Aorta.
Rationale:
Chemical receptors in the aorta send signals to begin the inspiration process. The brain, lungs, and heart all are affected by this chemical reaction.
The nurse knows that the primary function of the alveoli is to
- Carry out gas exchange.
- Store oxygen.
- Regulate tidal volume.
- Produce hemoglobin.
- Carry out gas exchange.
Rationale:
The alveolus is a capillary membrane that allows gas exchange of oxygen and carbon dioxide during respiration. The alveoli do not store oxygen, regulate tidal volume, or produce hemoglobin.
The nurse knows that anemia will result in
- Hypoxemia.
- Impaired ventilation.
- Hypovolemia.
- Decreased lung compliance.
- Hypoxemia.
Rationale:
Patients who are anemic do not have the same level of oxygen-carrying capacity. As a result, oxygen is unable to properly perfuse the tissues, resulting in hypoxemia. Impaired ventilation occurs when oxygen/carbon dioxide exchange occurs at the alveolar level. Hypovolemia is related to decreased circulating blood volume. Lung compliance is related to the elasticity of the lung tissue.
The process of exchanging gases through the alveolar capillary membrane is known as
- Disassociation.
- Diffusion.
- Perfusion.
- Ventilation.
- Diffusion.
Rationale:
Diffusion is the process of gases exchanging across the alveoli and capillaries of body tissues. Disassociation is not related to oxygenation. Perfusion is the ability of the cardiovascular system to carry oxygenated blood to tissues and return deoxygenated blood to the heart. Ventilation is the process of moving gases into and out of the lungs.
A nurse caring for a patient who was in a motor vehicle accident that resulted in trauma to C4 would expect to find
- Decreased tidal volumes.
- Increased perfusion.
- Increased use of accessory muscles.
- Decreased hemoglobin.
- Decreased tidal volumes.
Rationale:
A C4 injury would result in damage to the phrenic nerve and would cause a decrease in inspiratory lung expansion. Accessory muscles will also be damaged by a C4 injury. The patient may exhibit decreased perfusion and increased hemoglobin to compensate for hypoxemia.
The nurse would expect to see increased ventilations if a patient exhibits
- Increased oxygen saturation.
- Decreased carbon dioxide levels.
- Decreased pH.
- Increased hemoglobin levels.
- Decreased pH.
Rationale:
Retained CO2 creates H+ byproducts that lower pH. This sends a chemical signal to increase respiratory rate and would result in increased ventilation. All other options would cause the ventilation rate to normalize or decrease to increase carbon dioxide retention or as the result of delivery of higher levels of oxygen to tissues.
The nurse recommends that a patient install a carbon monoxide detector in the home because
- It is required by law.
- Carbon monoxide tightly bonds to hemoglobin, causing hypoxia.
- Carbon monoxide signals the cerebral cortex to cease ventilations.
- Carbon monoxide combines with oxygen in the body and produces a deadly toxin.
- Carbon monoxide tightly bonds to hemoglobin, causing hypoxia.
Rationale:
Carbon monoxide has a higher affinity for hemoglobin; therefore, oxygen is not able to bond to hemoglobin and be transported to tissues. A carbon monoxide detector is not required by law, does not signal the cerebral cortex to cease ventilations, and does not combine with oxygen but with hemoglobin to produce a toxin.
While performing an assessment, the nurse hears crackles in the patient’s lung fields. The nurse also learns that the patient is sleeping on three pillows. What do these symptoms most likely indicate?
- Left-sided heart failure
- Right-sided heart failure
- Atrial fibrillation
- Myocardial ischemia
- Left-sided heart failure
Rationale:
Left-sided heart failure results in pulmonary congestion, the signs and symptoms of which include shortness of breath, crackles, and discomfort when lying supine. Right-sided heart failure is systemic and results in peripheral edema and hepatojugular distention. Atrial fibrillation results in an irregular heart rate. Myocardial ischemia most often results in chest pain, along with shortness of breath, nausea, and fatigue.
The nurse knows that a myocardial infarction is an occlusion of what blood vessel?
- Pulmonary artery
- Ascending aorta
- Coronary artery
- Carotid artery
- Coronary artery
Rationale:
A myocardial infarction is the lack of blood flow due to obstruction to the coronary artery, which supplies the heart with blood. The ascending aorta is a vessel that leads from the heart to perfuse the brain. The pulmonary artery supplies blood to the lungs. The carotid artery supplies blood to the brain.
The nurse caring for a patient with ischemia to the left coronary artery would expect to find
- Increased ventricular diastole.
- Increased stroke volume.
- Decreased preload.
- Decreased afterload.
- Decreased afterload.
Rationale:
The left coronary artery supplies the muscles of the left ventricle; the strength of the muscle affects the contractility of the heart. The other options are not impacted by the muscles of the left ventricle.
Normal cardiac output is 4 to 6 L/min in a healthy adult at rest. Which of the following is the correct formula to calculate cardiac output?
- Stroke volume Heart rate
- Stroke volume/Body surface area
- Body surface area Cardiac index
- Heart rate/Stroke volume
- Stroke volume Heart rate
Rationale:
Cardiac output can be calculated by multiplying the stroke volume and the heart rate. The other options are not measures of cardiac functioning.
A patient’s heart rate increased from 80 bpm to 160 bpm. The nurse knows that what will follow is a(n)
- Increase in diastolic filling time.
- Decrease in cardiac output.
- Increase in stroke volume.
- Increase in contractility.
- Decrease in cardiac output.
Rationale:
An increased heart rate would decrease the diastolic filling time and stroke volume, thus decreasing overall cardiac output. A decrease in cardiac output results from decreased stroke volume and/or decreased heart rate. An increase in stroke volume and contractility would cause a decrease in heart rate to maintain cardiac output.
The nurse is careful to monitor a patient’s cardiac output because this helps the nurse to determine
- Peripheral extremity circulation.
- Oxygenation requirements.
- Cardiac arrhythmias.
- Ventilation status.
- Peripheral extremity circulation.
Rationale:
Cardiac output indicates how much blood is being circulated systemically. Oxygen status would be determined by pulse oximetry and the presence of cyanosis. Cardiac arrhythmias are an electrical impulse monitored through 5-lead ECG. Ventilation status is not solely dependent on cardiac output.
A nurse is assisting a patient with ambulation. The patient becomes short of breath and begins to complain of sharp chest pain. Which action by the nurse is the first priority?
- Call for the emergency response team to bring the defibrillator.
- Have the patient sit down in the nearest chair.
- Return the patient to the room and apply 100% oxygen.
- Ask a coworker to get the ECG machine STAT.
- Have the patient sit down in the nearest chair.
Rationale:
The patient is experiencing cardiac distress for reasons unknown. The nurse should first secure the safety of the patient and decrease the workload on the patient’s heart by putting him in a resting position; this will increase cardiac output by decreasing after load. Once the patient is stable, the nurse can obtain oxygen to put on the patient. Next, the nurse can begin to monitor the patient’s oxygen and cardiac status. If necessary, the emergency team may be activated to defibrillate.
A patient has inadequate stroke volume related to decreased preload. The nurse anticipates
- Placing the patient on oxygen monitoring.
- Administering vasodilators.
- Verifying that the blood consent form has been signed.
- Preparing the patient for dialysis.
- Verifying that the blood consent form has been signed.
Rationale:
Preload is affected by the circulating volume; if the patient has decreased fluid, it will need to be replaced with fluid or blood therapy. Before administering blood products, a type and match should be preformed. Monitoring the patient’s oxygenation status will not affect preload. Administering vasodilators affects afterload. Dialysis would further remove fluid from the patient, thus decreasing preload.
When caring for a patient with atrial fibrillation, the nurse is most concerned with which vital sign?
- Heart rate
- Pain
- Oxygen saturation
- Blood pressure
- Oxygen saturation
Rationale:
Atrial fibrillation results in pooling of blood in the atria, forming emboli that can be pumped out to the rest of the body. The most common manifestations are stroke, myocardial infarction, and pulmonary embolus. A sudden and drastic drop in oxygenation and blood pressure can indicate both pulmonary embolus and myocardial infarction.
The nurse would expect a patient with right-sided heart failure to have which of the following?
- Peripheral edema
- Basilar crackles
- Chest pain
- Cyanosis
- Peripheral edema
Rationale:
Right-sided heart failure results from inability of the right side of the heart to pump effectively, leading to a systemic backup. Peripheral edema and hepatojugular distention are signs of right-sided failure. Basilar crackles can indicate pulmonary congestion from left-sided heart failure. Cyanosis and chest pain result from inadequate tissue perfusion.
The P wave is represented by which portion of the conduction system?
- SA node
- AV node
- Bundle of HIS
- Purkinje network
- SA node
Rationale:
The SA node initiates electrical conduction through the atria. The AV node conducts down through the bundle of HIS and the Purkinje network to cause ventricular contraction.