A patient comes to the Emergency Department complaining of chest pain.

Her EKG shows ST elevation myocardial infarction (STEMI). You are working in the Emergency Department at a hospital that does not have percutaneous coronary intervention (PCI) capabilities and there is not one close by. The doctor decides to order thrombolytic therapy for this patient.

As the nurse, you know this should be given within which timeframe?

Choice A rationale

Ordering a breathing treatment, such as a bronchodilator, is appropriate for a patient with documented bronchospasm or underlying reactive airway disease. Since CABG patients are generally high-risk for atelectasis due to incisional pain, a more generalized and preventative measure like an incentive spirometer is the priority intervention.

Choice B rationale

Giving adequate pain medication is crucial because post-surgical pain leads to shallow breathing and splinting, which directly increases the risk of atelectasis and pneumonia. However, while pain control facilitates respiratory efforts, the direct and most effective intervention to prevent collapse of the alveoli is mechanical lung inflation.

Choice C rationale

Applying oxygen via nasal cannula is used to treat or prevent hypoxemia by increasing the fraction of inspired oxygen (FiO_2). Unless the patient's oxygen saturation is low (normal SpO_2 is 95-100%), this is not a primary intervention to prevent respiratory mechanical compromise like atelectasis; it merely treats the resulting hypoxemia.

Choice D rationale

Incentive spirometry is the most crucial mechanical intervention for preventing postoperative respiratory complications in CABG patients. It encourages maximal inspiratory effort, which helps re-expand collapsed alveoli, preventing atelectasis and subsequent pneumonia caused by shallow, painful post-sternotomy breathing. —.

Choice A rationale

Forceful coughing increases intrathoracic pressure and vagal stimulation, activating the parasympathetic system to slow AV nodal conduction. This vagal maneuver transiently interrupts reentrant circuits responsible for paroxysmal supraventricular tachycardia (PSVT), restoring normal sinus rhythm. The maneuver is noninvasive, first-line, and physiologically effective for terminating AV nodal reentry tachycardia by enhancing acetylcholine-mediated suppression of nodal conduction velocity and refractory period shortening.

Choice B rationale

Bearing down as during a bowel movement, known as the Valsalva maneuver, similarly increases vagal tone. The increased intrathoracic pressure transiently reduces venous return, stimulating baroreceptors and causing reflex bradycardia. This vagal reflex inhibits reentrant impulses through the AV node, terminating PSVT episodes. The Valsalva maneuver is evidence-based, safe, and recommended as the initial nonpharmacologic intervention before pharmacologic or electrical therapy.

Choice C rationale

Jumping up and down once has no physiologic effect on vagal tone or AV nodal conduction. PSVT involves a reentrant circuit within or near the AV node, requiring vagal or pharmacologic interruption. Physical exertion like jumping may transiently increase sympathetic output, worsening tachycardia rather than terminating it. Therefore, this action provides no therapeutic value and is not recommended for PSVT management.

Choice D rationale

Adenosine rapidly blocks AV nodal conduction by hyperpolarizing nodal tissue through A1 receptor activation, effectively terminating AV nodal reentrant tachycardia. It is administered as a rapid intravenous bolus due to its 10-second plasma half-life. Adenosine temporarily induces asystole before sinus rhythm resumes. It is a first-line pharmacologic intervention when vagal maneuvers fail, demonstrating high efficacy in converting PSVT to normal sinus rhythm.