A 58-year-old female internist, Dr. Emily Clarke, practicing in a busy Vancouver outpatient clinic, has recently exhibited concerning behaviours. Several residents and nurses have reported instances where Dr. Clarke appeared disoriented or fell asleep during patient consultations, particularly during afternoon clinics. One specific incident involved her falling asleep during a consultation with a patient discussing critical medication adjustments for their heart failure, leading to the patient feeling unheard and neglected. Her colleagues have also noted increased irritability and occasional difficulty recalling recent patient information. The Chief of Medicine has received multiple informal complaints and is now considering the appropriate professional and ethical steps regarding Dr. Clarke's clinical fitness to practice. What is the most appropriate initial action for the Chief of Medicine to take?