Hyperkalemia, or high serum potassium levels, can have serious cardiac effects and is usually more dangerous than hypokalemia. The most important consequence of hyperkalemia is its effect on the myocardium, with cardiac conduction disturbances occurring as potassium levels rise above 7-8 mEq/L. Diagnosis involves measuring serum potassium levels and obtaining an electrocardiogram to detect changes. Treatment aims to lower potassium levels through intravenous calcium gluconate, sodium bicarbonate, insulin with dextrose, and dialysis if needed.

2.  Hyperkalemia (greater-than-normal serum potassium
concentration)
 seldom occurs in patients with normal renal function. Like
 hypokalemia, hyperkalemia is often due to iatrogenic
(treatmentinduced)
 causes. Although less common than hypokalemia,
hyperkalemia
 is usually more dangerous because cardiac arrest is more
 frequently associated with high serum potassium levels.

3.  Clinical Manifestations
 The most important consequence of hyperkalemia is its effect
on
 the myocardium. Cardiac effects of an elevated serum
potassium
 level are usually not significant below a concentration of 7
mEq/L
 (7 mmol/L), but they are almost always present when the
level is
 8 mEq/L (8 mmol/L) or greater. As the plasma potassium level
rises,
 disturbances in cardiac conduction occur.

4.  Assessment and Diagnostic Findings
 Serum potassium levels and ECG changes are crucial to the
diagnosis
 of hyperkalemia, as discussed above. Arterial blood gas
analysis
 may reveal metabolic acidosis; in many cases, hyperkalemia
 occurs with acidosis.

5.  An immediate ECG should be obtained to detect changes.
 restriction of dietary potassium and potassium-containing
medications.

6.  When serum potassium levels are elevated, necessary to
administer IV calcium gluconate.
 Within minutes after administration, calcium antagonizes the
action of hyperkalemia on the heart.
 Infusion of calcium does not reduce the serum potassium
concentration but immediately antagonizes the adverse
cardiac conduction abnormalities.

7.  Monitoring the blood pressure is essential to detect
hypotension,which may result from the rapid IV
administration of calcium gluconate.
 The ECG should be continuously monitored during
administration;
 the appearance of bradycardia is an indication to stop the
infusion.

8.  IV administration of sodium bicarbonate may be necessary to
alkalinize the plasma and cause a temporary shift of
potassium into the cells.

9.  IV administration of regular insulin and a hypertonic dextrose
 solution causes a temporary shift of potassium into the cells.

10.  Actual removal of potassium from the body is required; this
may be accomplished by
 peritoneal dialysis,
 hemodialysis or
 other forms of renal replacement therapy.

11.  Patients at risk for potassium excess, for example those with
renal
 failure, should be identified so they can be monitored closely
for
 signs of hyperkalemia.

12.  The nurse observes for signs of muscle
 weakness and dysrhythmias. The presence of paresthesias is
noted,
 as are GI symptoms such as nausea and intestinal colic. For
patients
 at risk, serum potassium levels are measured periodically.