From the Guidelines
Hyperkalemia after surgical amputation is primarily caused by tissue trauma and cell damage during surgery, which releases intracellular potassium into the bloodstream, and can be exacerbated by various factors such as crush injuries, reperfusion injury, acidosis, acute kidney injury, blood transfusions, and certain medications. The causes of hyperkalemia after surgical amputation can be multifactorial, involving several mechanisms that contribute to the elevation of serum potassium levels.
- Tissue trauma and cell damage during surgery release intracellular potassium into the bloodstream, as potassium homeostasis is largely maintained by the kidneys, although the gastrointestinal tract and other systems are also involved to a lesser extent 1.
- Crush injuries or extensive tissue damage during amputation can lead to rhabdomyolysis, causing massive potassium release from damaged muscle cells.
- Reperfusion injury may occur when blood flow returns to previously ischemic tissues, washing potassium that accumulated during ischemia back into circulation.
- Acidosis from tissue hypoperfusion or tourniquet use can drive potassium out of cells, raising serum levels, and hyperkalemia has depolarizing effects on the heart, causing shortened action potentials and increasing the risk of arrhythmias 1.
- Acute kidney injury following surgery may impair potassium excretion, especially in patients with pre-existing renal dysfunction, and the risk of mortality, cardiovascular morbidity, progression of CKD, and hospitalization is increased in patients with hyperkalemia, especially those with CKD, HF, and diabetes 1.
- Blood transfusions during amputation surgery can contribute to hyperkalemia as stored blood contains higher potassium levels due to red blood cell breakdown during storage.
- Medications used perioperatively, such as potassium-sparing diuretics, ACE inhibitors, or NSAIDs, may exacerbate the condition, and patients with diabetes or adrenal insufficiency are at higher risk due to impaired potassium regulation. Management includes close monitoring of potassium levels post-amputation, especially in high-risk patients, and prompt treatment of hyperkalemia with calcium gluconate, insulin with glucose, beta-agonists, or dialysis in severe cases, considering the optimal range for serum K+ concentrations varies according to individual patient comorbidities, such as CKD, HF, or diabetes 1.
From the Research
Causes of Hyperkalemia after Surgical Amputation
- Hyperkalemia can occur due to various factors, including altered potassium distribution, reduced urinary excretion, or an exogenous potassium load 2
- Surgical conditions that may lead to hyperkalemia include rhabdomyolysis from malpositioning, trauma, or medications, as well as vascular procedures with tissue ischemia 2
- Certain acute conditions and chronic co-morbidities, such as chronic kidney disease, diabetes mellitus, and the use of certain medications (e.g. beta blockers, salt substitutes), can also increase the risk of hyperkalemia 2, 3
- Renal failure, adrenal disease, and the use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or potassium-sparing diuretics can limit renal potassium excretion and contribute to hyperkalemia 3
- Metabolic acidosis, which can occur after major surgery, may also be related to hyperkalemia, particularly if it is caused by hyperchloremic acidosis associated with large saline infusion or lactic acidosis caused by lactataemia 4
Risk Factors
- Chronic kidney disease 3
- Diabetes mellitus 2, 3
- Adrenal disease 3
- Use of certain medications, such as beta blockers, salt substitutes, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or potassium-sparing diuretics 2, 3
- Rhabdomyolysis from malpositioning, trauma, or medications 2
- Vascular procedures with tissue ischemia 2
- Metabolic acidosis, particularly hyperchloremic acidosis or lactic acidosis 4