This week we are gonna talk about something which we come across in the ED almost everyday.
We all learned to look for the ECG changes for hyperK and also how the changes correlate with the levels of potassium.
K levels ECG changes
5.5 - 6.5 Tall tented T waves
6.5 - 7.5 Loss of P waves
7.5 - 8.5 Widening QRS
> 8.5 Sine Wave pattern, Ventricular Arrythmias
Well, Don't waste your time in memorising these changes and the corresponding potassium levels. Patients don't read textbooks and they don't follow this textbook pattern of ECG changes.
A potassium of 8 may not produce any ECG changes and at the same time Ventricular Fibrillation can be the first ECG change in hyperK. So if they have elevated K which concerns you, just go ahead and give them some calcium regardless of ECG changes. And if they have ECG changes with hyperK, be more aggressive with the correction.
HyperK often comes up with strange rhthyms and I learned this pearl from the EKG Guru "Amal Mattu" --> "Any bizarre EKG changes, think hyperKalemia and try some calcium". Lets hear it from the EKG GOD himself.
Weisberg LS. Management of severe hyperkalemia. Crit Care Med. 2008 Dec;36(12):3246-51.