The nurse reviews the mixed venous sample from the pulmonary artery catheter and notes the SvO2 to be 70 The nurse understands the meaning of this value to be which of the following?

Choice A rationale

Flushing with saline before administration is correct to ensure line patency, but giving a potent medication like digoxin as a rapid push is unsafe. Digoxin is a cardiac glycoside that increases the force of myocardial contraction and slows the heart rate. Normal serum levels are 0.5 to 2.0 ng/mL. Rapid administration can cause intense vasoconstriction and cardiac arrhythmias. It must be delivered slowly to allow the medication to distribute and to monitor the heart's response.

Choice B rationale

Administering the medication first without ensuring the line is patent is poor practice. More importantly, waiting five minutes before flushing does not address the need for a slow, controlled delivery of the drug. Digoxin must be administered slowly over at least five minutes to prevent toxic peaks and to mitigate the risk of bradycardia or heart block. Flushing after the medication is necessary to ensure the entire dose is delivered from the IV tubing into the bloodstream.

Choice C rationale

Injecting intravenous push medications into a primary IV bag is generally incorrect for drugs intended for rapid but controlled delivery. This dilutes the medication significantly and changes the rate of delivery to whatever the primary infusion rate is set to, rather than the intended five minute duration. Digoxin should be given as a slow direct injection or via a secondary "piggyback" if specified, but the standard protocol for IVP digoxin is slow manual administration over several minutes.

Choice D rationale

The safest method for administering digoxin IVP is to inject it slowly in small increments over a period of at least five minutes. This slow delivery minimizes the risk of sudden cardiac toxicity and allows the nurse to monitor the patient for adverse effects like significant bradycardia. Following the medication with a saline flush ensures the full dose reaches the patient. This controlled approach is vital because digoxin has a narrow therapeutic index and potent effects on cardiac conduction.

Choice A rationale

Ventricular tachycardia is characterized by a rapid, wide QRS complex rhythm originating from the ventricles. While it can occur without a pulse, the prompt describes a normal sinus rhythm on the monitor. Ventricular tachycardia would show a distinct lack of P waves and a heart rate typically above 100 beats per minute. Because the monitor shows a normal pattern but the patient is unresponsive with no pulse, this diagnosis is scientifically incorrect.

Choice B rationale

Pulseless electrical activity occurs when the heart's electrical conduction system functions in a relatively normal organized fashion, but the myocardium fails to produce a mechanical contraction or sufficient stroke volume to generate a palpable pulse. This results in an organized rhythm like sinus rhythm on the ECG monitor despite the clinical state of cardiac arrest. It requires immediate CPR and identification of reversible causes such as hypovolemia, hypoxia, or electrolytes imbalances to restore mechanical function.

Choice C rationale

Sudden cardiac death is a broad clinical term used to describe an unexpected natural death due to cardiac causes, usually within one hour of symptom onset. While the patient in the scenario is in cardiac arrest, the term does not describe the specific cardiac rhythm observed on the monitor. It is a clinical outcome rather than a rhythmic classification. The nurse must identify the specific rhythm to guide the advanced cardiovascular life support interventions required.

Choice D rationale

Premature ventricular contractions are single ectopic beats that interrupt the regular underlying rhythm and are usually followed by a compensatory pause. They do not typically cause a complete loss of pulse or unresponsiveness unless they occur so frequently that they transition into a more lethal arrhythmia. A rhythm that looks like normal sinus rhythm but lacks a pulse is a systemic failure of mechanical output, not a minor electrical irritability issue like PVCs.