A patient is admitted to the emergency department with chest pain and ECG findings showing ST-segment elevation.
The nurse notes oxygen saturation at 89 Which intervention should the nurse prioritize to initiate first?
Administer nitroglycerin immediately to reduce chest pain and lower blood pressure regardless of hemodynamic status.
Administer supplemental oxygen to maintain saturation above 94
Place the patient in supine position to optimize cardiac output and prepare for administration of morphine for pain control.
Start thrombolytic therapy immediately as first-line treatment before obtaining vascular access or ECG monitoring.
The Correct Answer is B
Choice A rationale
Administering nitroglycerin is a standard treatment for chest pain because it induces vasodilation of the coronary arteries. However, prioritizing it over oxygen in a patient with an oxygen saturation of 89 percent is incorrect. Nitroglycerin can significantly lower blood pressure, and it should only be administered after assessing hemodynamic stability. In this clinical scenario, addressing the documented hypoxemia takes precedence to ensure myocardial tissue receives adequate oxygenation to prevent further ischemic damage.
Choice B rationale
Supplemental oxygen is the priority because the patient is hypoxemic, with a saturation below the normal range of 95 to 100 percent. Oxygen therapy increases the partial pressure of oxygen in the blood, enhancing delivery to the myocardium. Correcting hypoxemia reduces the workload on the heart and limits the size of the infarction. Current guidelines emphasize maintaining oxygen saturation at or above 94 percent to optimize cellular respiration and prevent systemic metabolic acidosis.
Choice C rationale
The supine position is not ideal for a patient experiencing chest pain and respiratory distress because it increases venous return and cardiac preload, potentially worsening pulmonary congestion. Positioning the patient in semi-Fowler or high-Fowler position is usually preferred to facilitate lung expansion. While morphine is used for pain that is unresponsive to nitrates, it is not the first priority. Oxygenation must be addressed immediately to mitigate the underlying cause of the myocardial hypoxia.
Choice D rationale
Thrombolytic therapy is a critical intervention for ST-segment elevation myocardial infarction when percutaneous intervention is unavailable, but it is never initiated before establishing vascular access and confirming the diagnosis via a 12-lead ECG. Furthermore, safety screening for contraindications like recent surgery or bleeding disorders is mandatory. Starting this treatment without basic stabilization, such as oxygen administration for a desaturating patient, violates the primary assessment sequence of airway, breathing, and circulation.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A rationale
Ventricular fibrillation represents the most disorganized and lethal cardiac rhythm because it involves multiple re-entrant circuits in the ventricles. There is no coordinated depolarization of myocardial tissue, which results in the absence of mechanical contraction and cardiac output. Since there is no organized atrial or ventricular depolarization, the ECG lacks P waves, QRS complexes, and T waves. The tracing appears as a wavy, undulating line with varying amplitude and frequency known as coarse or fine fibrillation.
Choice B rationale
A regular rhythm with a rate exceeding 150 beats per minute and widened QRS complexes greater than 0.12 seconds typically describes ventricular tachycardia. This rhythm originates from an ectopic focus in the ventricles and can lead to hemodynamic instability, but it maintains a degree of organization that ventricular fibrillation lacks. While it is serious, the electrical signals are still forming distinct complexes, unlike the chaotic oscillations seen in fibrillation where the muscle fibers simply quiver without pumping blood.
Choice C rationale
A saw-tooth appearance on an ECG is the hallmark of atrial flutter. This pattern is caused by a macro-re-entrant circuit in the atria, usually around the tricuspid valve, occurring at a rate of 250 to 350 beats per minute. This results in regular "F" waves. The ventricular response depends on the conduction ratio through the atrioventricular node. This is a supraventricular tachycardia and is distinct from the chaotic ventricular activity that defines the life-threatening state of ventricular fibrillation.
Choice D rationale
Normal sinus rhythm with occasional premature ventricular contractions describes a baseline rhythm originating from the sinoatrial node with a rate of 60 to 100 beats per minute. The occasional premature ventricular contractions are early QRS complexes that are wide and bizarre in shape because they originate from the ventricles rather than the normal conduction system. This is a common finding and does not represent the total loss of organized electrical activity and cardiac output seen in fibrillation.
Correct Answer is A
Explanation
Choice A rationale
Transcutaneous pacing is the immediate treatment of choice for symptomatic sinus bradycardia that does not respond to atropine. This non-invasive method delivers electrical impulses through large electrode pads placed on the chest and back to stimulate ventricular contraction. It serves as a crucial bridge until more definitive treatments, like a transvenous or permanent pacemaker, can be established. It is rapid to initiate and effective in maintaining an adequate heart rate and cardiac output.
Choice B rationale
An implanted or permanent pacemaker is a long-term solution for chronic or irreversible bradycardia, but it is not the immediate treatment for an acute, sudden-onset event in an unstable patient. The placement of a permanent device requires a surgical procedure and time for preparation. In an emergency where a patient is not responding to atropine, a faster, temporary method like transcutaneous pacing must be used first to stabilize the patient before considering a permanent implant.
Choice C rationale
An asynchronous defibrillator is used to deliver high-energy shocks to treat pulseless rhythms like ventricular fibrillation or pulseless ventricular tachycardia. It is not used for bradycardia, as the heart still has organized, albeit slow, electrical activity. Applying an unsynchronized shock to a patient with a pulse could induce a more dangerous rhythm, such as ventricular fibrillation, by hitting the T wave. Defibrillation is entirely inappropriate for a slow heart rate with a pulse.
Choice D rationale
Synchronized cardioversion is used to treat unstable tachydysrhythmias, such as supraventricular tachycardia or atrial fibrillation with a rapid ventricular response. The goal is to slow down or reset a fast heart rate. Using cardioversion on a patient with sinus bradycardia would be counterproductive and dangerous, as the patient's heart rate is already too slow. This intervention is designed to interrupt fast circuits, not to provide the regular stimulus needed to increase a slow rate.
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