Last week one of our second-year fellows was called into the ER for a potassium of 9.9 mEq/L. The EKG you see above was waiting for him. He arranged for emergent dialysis. In the morning the patients EKG looked like this:
Here is the time line of events:
- 17:24 Na 128, HCO3 9, Cl 103, BUN 100, Cr 5.6 (no potassium was reported out on the initial labs)
- 18:06 First EKG done
- 18:28: K=9.9
- 18:28: U/A Sp Grav 1.012, pH 5, random drug screen positive for opioids
- 18:45: ABG 7.05/37/408/10
- 18:45: urine Na 89, urine Cr 50.5, FENa 4.7%
- 23:00 initiate dialysis: 2 hours on 1 K bath
- 01:00 complete dialysis
- 03:30 Na 140, K 5, Cl 107, HCO3 16, BUN 67, Cr 3.8, Ca 9.1, Phos 6.4, Mg 1.4, CPK 941
- 03:30 ABG 7.22/40/117
- 09:20 Na 142, K 4.8, Cl 111, HCO3 15, BUN 63, Cr 3.2
- 10:00 ABG 7.20/42/96
His initial EKG is the best example of a sine wave from hyperkalemia I have ever seen. Below is a cardiac cycle from V4. With a quick glance it may look like a very wide QRS complex with the t wave somewhere to the right of the picture. In reality, the QRS duration is only 176 msec and the large upward thrust is the peaked T wave.
EKG Changes with hyperkalemia
- Peaked T waves
- Shortened QT interval
- Widened QRS
- Sine wave
