Monday, December 28, 2015

K 8.7 mmol/l ! You want to know what the EKG shows??


  • Women in her 60's presents with septic shock from HCAP, currently bacteremic. She was oliguric. On admission her Serum Potassium was 8.7 mmol/l. Prior to admission medications included PO Bactrim for PCP prophylaxis. 
  • Focus of this article is to display the EKG changes associated with hyperkalemia in this patient. 

EKG at 1am: 

Initial EKG with K 8.7 mmol/l showed:

  1. Almost sine wave pattern
  2. Wide complex tachycardia 

We treated the patient with IV calcium gluconate, Normal saline boluses, IV Furosemide, Albuterol nebulizer, Sodium bicarbonate drip, Insulin Dextrose.


EKG at 2am: 

One hour post treatment, K was 7.1mmol/l. A repeat EKG showed:

  1. 1st degree AV block
  2. Prolonged QRS interval
  3. QTc prolongation
  4. Resolution of sine wave pattern.

We repeated the above mentioned treatments, consulted renal (just to feel safe).


EKG at 3am: 

One hour later, K was 6 mmol/l. A repeat EKG showed:

  1. Non specific ST changes. Otherwise normal EKG
  2. Resolution of AV block. 
  3. QRS no longer prolonged. 

Eventually her urine output improved with IV fluids and lasix. K level normalized in 6hrs. Did not need dialysis.



  • Hold bactrim as it can cause hyperkalemia due to blockade of the collecting tubule sodium channel by trimethoprim (an action similar to that induced by the potassium-sparing diuretic amiloride); this is most common in HIV-infected patients who are treated with high doses, but normal doses can produce a modest elevation in the plasma potassium concentration in non-HIV-infected subjects
  • Not every hyperkalemia patient has tented T waves on EKG. Peaked T waves are only one of the many EKG manifestations of hyperkalemia. 



As a general rule, mentioned below are the EKG findings associated with various stages of hyperkalemia:

  1. K >5.5 mmol/L is associated with repolarization abnormalities
      1. Peaked T waves (usually the earliest sign of hyperkalaemia)
  2. K >6.5 mmol/L is associated with progressive paralysis of the atria:
      1. P wave widens and flattens
      2. PR segment lengthens
      3. P waves eventually disappear
  3. K >7.0 mmol/L is associated with conduction abnormalities and bradycardia:
      1. Prolonged QRS interval with bizarre QRS morphology
      2. High-grade AV block with slow junctional and ventricular escape rhythms
      3. Any kind of conduction block (bundle branch blocks, fascicular blocks)
      4. Sinus bradycardia or slow AFDevelopment of a sine wave appearance (a pre-terminal rhythm)
  4. K >9.0 mmol/L causes cardiac arrest due to:
      1. Asystole
      2. Ventricular fibrillation
      3. PEA with bizarre, wide complex rhythm

2. UpToDate

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