A nurse is reviewing the EKG strip of a client who has prolonged vomiting. Which of the following abnormalities on the client's EKG should the nurse interpret as a sign of hypokalemia?

Choice A reason: Inverted P waves are typically associated with ectopic atrial rhythms or junctional rhythms, not hypokalemia. While hypokalemia can affect atrial conduction, inverted P waves are not a hallmark finding. Choice B reason: Elevated ST segments are more indicative of myocardial injury or pericarditis. Hypokalemia is associated with ST depression rather than elevation, making this choice incorrect in the context of electrolyte imbalance. Choice C reason: Abnormally prominent U waves are a classic and specific EKG finding in hypokalemia. They result from delayed repolarization of the Purkinje fibers and are best seen in the precordial leads. Their presence strongly suggests potassium depletion and warrants prompt correction to prevent arrhythmias. Choice D reason: A wide QRS complex is more commonly associated with hyperkalemia or other conduction delays such as bundle branch blocks. In hypokalemia, QRS widening is not a typical early finding and may only occur in severe cases with arrhythmias.