The back to basics doctor

Back to basics

You go back to basics and give the dehydrated patient some N. Saline 0.9% with 40mmol KCl. Next door, a patient was due to receive 10ml of 10% calcium chloride. By mistake, both the calcium chloride and the N.Saline 0.9% with 40mmol KCL were given to your patient.  Initially, he seems a bit better.

Suddenly, his observations are now: pulse 140, BP 122/68 mmHg, temp 37.1, RR 28, sats 100% oa

You do an ECG. Your visual mind sees a tent under the T wave:

What has likely caused this ECG change?

Hypernatremia

Hypercalcemia

Hyperkalemia