<prompt> Immediate treatment for hyperkalemia with significant ECG changes?Calcium chlorideCalcium hydroxideK Binding Resin EnemaCalcium Carbonate  <response>: Calcium increases threshold potential- restoring normal gradient between threshold potential and resting membrane potential elevated abnormally in hyperkalemia Calcium chloride - onset of action is 5min and lasts about 30-60 min. Doses should be titrated with constant monitoring of ECG changes during administration Potassium binding resin exchanges Na for K :onset of action after PO ranges from 2-12 h. Calcium hydroxide and calcium carbonate have no role in management of hyperkalemia. 