Patients in this arm will be administered intravenous potassium if they develop hypokalemia. As per CICU protocol 1-ml blood sample from already placed art-line or central venous line is sent for analysis of serum potassium concentration in all the immediate post operative patients. In the IVPR group, potassium will be given according to the hospital protocol through a central line. As per a previously established protocol and bioavailability data, repeat serum potassium will be sent 1 hour after replacement in the IVPR group.

Once included in the study, patients in this arm will be given oral potassium if they develop an episode of hypokalemia. As per CICU protocol 1-ml blood sample from already placed art-line or central venous line is sent for analysis of serum potassium concentration in all the immediate post operative patients. As per a previously established protocol and bioavailability data, repeat serum potassium will be sent 2 hours after replacement in the EPR group. Replacement and serum level monitoring will be done till the episode of hypokalemia is resolved

The intervention arms will be blocked randomized as alternate week for I/V and enteral potassium replacement for trial's operational feasibility. Recruited patients will receive treatment accordingly.

In case where a patient develops side effects such as diarrhea or vomiting, even though he will be changed to IV route of potassium supplement, he will be considered enteral supplementation during data analysis till the point when the patient had received enteral replacement.

In the IVPR group, potassium will be given according to the hospital protocol through a central line. As per a previously established protocol, repeat serum potassium will be sent 1 hour after replacement in the IVPR group and 2 hours after replacement in the EPR group. Replacement and serum level monitoring will be done till the episode of hypokalemia is resolved.

Adverse effects that will be monitored are hyperkalemia (defined as potassium levels > 5 mEq/L, arrhythmias (defined as any rhythm other than sinus during or within 2 hours of potassium replacement), diarrhea (described as > 2 loose stools or a single watery stool, during or within 2 hours of potassium replacement , GI bleeds, nausea and vomiting (during or within 2 hours of potassium replacement). These adverse events will be monitored on hourly bases by the CICU nursing staff as per CICU protocol. These adverse events will be documented on the CICU nursing sheet (as per routine) and the data gathered every morning by the principal or co-investigators. The on-call physician will be contacted, as per routine, by the nursing to determine any change in mode/dose of potassium replacement if adverse events occur. The on-call physician will in-turn contact either the principal or one of the co-investigators to further discuss the plan.