Which method would be appropriate to monitor for torsades de pointes in a client being treated with chlorpromazine?

Monitoring for torsades de pointes, a potentially life-threatening form of polymorphic ventricular tachycardia, is best achieved through the use of an electrocardiogram (ECG). This method allows for real-time observation of the heart's electrical activity and can detect changes in the QT interval, which is a significant risk factor for developing torsades de pointes.

Chlorpromazine, an antipsychotic medication, is known to potentially prolong the QT interval, making regular ECG assessments essential in patients receiving this treatment. Frequent ECG monitoring can facilitate early identification of any arrhythmias, including torsades de pointes, thereby allowing for prompt intervention to prevent serious complications.

While other methods such as blood pressure monitoring, oxygen saturation checks, and neurological assessments serve important roles in evaluating a patient’s overall condition and response to medications, they do not provide direct information about the heart's rhythm or potential dangerous changes that can lead to torsades de pointes. Therefore, the ECG is the most appropriate method for monitoring this specific risk associated with chlorpromazine treatment.