A client is receiving digoxin. Before administering the morning dose, the nurse should assess which vital sign?

DIGOXIN ADMINISTRATION SAFETY: ASSESS APICAL PULSE: Count the apical heart rate for ONE FULL MINUTE before each dose; HOLD AND NOTIFY: If apical HR < 60 bpm in adults (< 70 in children, < 90-110 in infants depending on protocol); WHY: Digoxin has negative chronotropic effect (slows heart rate) — giving it to a bradycardic patient can cause dangerous further slowing or heart block; DIGOXIN TOXICITY SIGNS: Bradycardia, nausea/vomiting, anorexia, visual disturbances (yellow-green halos, blurred vision), confusion, dysrhythmias; THERAPEUTIC LEVEL: 0.5-2.0 ng/mL (toxicity often > 2.0); RISK FACTORS for toxicity: hypokalemia (low potassium increases digoxin binding and toxicity), renal impairment, advanced age; ANTIDOTE: Digoxin immune Fab (Digibind) for severe toxicity; LPN ROLE: Always check apical pulse before digoxin; report bradycardia and toxicity signs immediately.