A patient is admitted with possible syndrome of inappropriate anti-diuretic hormone (SIADH). Which information obtained by the nurse is most important to communicate rapidly to the health care provider?

A. Increased preload: Preload refers to the volume of blood returning to the heart. In this patient, hypovolemia from vomiting, diarrhea, and gastrointestinal bleeding reduces circulating volume rather than increasing it, so increased preload is not the underlying issue.

B. Decreased afterload: Afterload is the resistance the left ventricle must overcome to eject blood. While hypovolemia may indirectly affect afterload, fluid resuscitation primarily targets restoring intravascular volume and preload, not directly correcting afterload.

C. Decreased preload: The patient’s prolonged fluid losses have led to hypovolemia, resulting in decreased venous return and reduced preload. Administering a fluid bolus increases circulating volume, improves ventricular filling, and enhances cardiac output, which is critical in hypovolemic shock.

D. Increased afterload: Increased afterload is usually seen in hypertension or vasoconstrictive states and is not the primary concern in a patient with fluid loss. Treating hypovolemia with fluids does not target elevated afterload but restores adequate preload for perfusion.

A. Begin cardiopulmonary resuscitation: Asystole indicates a complete absence of ventricular electrical activity, and the patient is pulseless and apneic. Immediate initiation of high-quality CPR is critical to maintain circulation and oxygen delivery to vital organs while advanced resuscitative measures are prepared. Early CPR improves the chance of return of spontaneous circulation.

B. Prepare to defibrillate: Defibrillation is effective for shockable rhythms such as ventricular fibrillation or pulseless ventricular tachycardia. Asystole is a non-shockable rhythm, so defibrillation would not restore cardiac activity and would delay essential CPR.

C. Begin rescue breathing with bag-valve-mask: While providing oxygenation is important, in a pulseless patient, chest compressions take priority over rescue breathing. CPR ensures perfusion of the brain and heart until advanced life support interventions can be applied.

D. Prepare to cardiovert: Synchronized cardioversion is indicated for unstable tachyarrhythmias such as atrial fibrillation or supraventricular tachycardia. It is not appropriate for asystole, which requires immediate CPR and administration of medications such as epinephrine under advanced life support protocols.