Normal muscle releases enough potassium during succinylcholine-induced depolarization to raise serum potassium by ~ 0.5 mEq/L. Although this is usually insignificant in patients with normal baseline potassium levels, it can be life-threatening in patients with preexisting hyperkalemia or those with burn injury, massive trauma, neurological disorders/spinal cord injury (as well as in tetanus, prolonged total body immobilization, ruptured cerebral aneurysm, hemorrhagic shock with metabolic acidosis, and myopathies [eg, Duchenne’s dystrophy])
In non-renal failure patients, induction with SCh increased [K+] by 0.4 mEq/ and by 0.09 mEq/L. Schow et al. reviewed 40,000 anesthetics at Duke University Medical Center, and found 38 cases in which SCh was used with a starting potassium > 5.5 mEq/L. No fatalities or arrhythmias occurred, and the authors estimated that the maximal risk of an event was 7.9% or less.
Adam J Schow, David A Lubarsky, Ronald P Olson, Tong J Gan Can succinylcholine be used safely in hyperkalemic patients? Anesth. Analg.: 2002, 95(1);119-22, table of contents
P H Manninen, B Mahendran, A W Gelb, R N Merchant Succinylcholine does not increase serum potassium levels in patients with acutely ruptured cerebral aneurysms. Anesth. Analg.: 1990, 70(2);172-5
M R Stacey, K Barclay, T Asai, R S Vaughan Effects of magnesium sulphate on suxamethonium-induced complications during rapid-sequence induction of anaesthesia. Anaesthesia: 1995, 50(11);933-6