Hypokalemia 3. 18 potassium. Hospital?

Respected sir/ ma'am My mother is diabetic hypertensive patients. She is on below mentioned treatment Chlorthalidone 12.5 mg Atorvastatin clopidogrel Metformin gliclazide combination Sitagliptin She has ankle edema 15-20 ago so physician started chlorthalidone. Yesterday mummy has palpitations and nausea bloating chest burn, chest pain We went to trauma and ECG was done There is abnormality in ECG so physician suggested Coronary angiography so angiography is done. Angiography was normal. But for angiography cardiologist suggested few tests including Serum potassium and serum sodium Serum potassium value is 3.18 which is less than normal value..mild hypokalemia Is it because of diuretic or do we need to adjust dose or switch to other drug . What can we give to increase potassium level ? What are danger signs of hypokalemia so we can identify it and rush to hospital?? Please guide me sir Thank you sir