The nurse is caring for a 65-year-old male client with a history of ischemic heart disease who has been admitted to the ICU following a myocardial infarction. The client is currently receiving lidocaine I.V. to manage his ventricular ectopy, which has been persistent. Which of the following factors would be most important for the nurse to consider in relation to the administration of this medication?
A. Decrease in arterial oxygen saturation (SaO2) when measured with a pulse oximeter
B. Increase in systemic blood pressure
C. Presence of premature ventricular contractions (PVCs) on a cardiac monitor
D. Increase in intracranial pressure (ICP)
E. A drop in serum potassium levels as indicated in the latest lab results
F. Observation of a widening QRS complex on the ECG