Succinylcholine hyperkalemia is hyperkalemia seen after the usage of succinylcholine. Succinylcholine is a depolarizing muscle relaxant used for urgent endotracheal intubation in the operating room, intensive care unit (ICU), and emergency department.
The intravenous (IV) dose is 0.5 to 1.5 mg/kg. Time to effect is 1 minute and duration of action in patients with normal pseudocholinesterase activity is approximately 2 minutes with complete recovery in 5 minutes.
If a working IV catheter is not available, succinylcholine may be given 3 to 4 mg/kg intramuscularly (IM) (maximum dose 150 mg) with an onset of 2 to 3 minutes. Muscle fasciculations will often be seen prior to complete muscle relaxation. Known side effects of succinylcholine are bradycardia and muscle pain.
Succinylcholine is indicated when rapid sequence induction is needed to quickly secure the airway with an endotracheal tube. Although succinylcholine may increase intracranial pressure, it can be used in patients with acute head trauma because the rapid onset, superior intubating conditions, and reversibility outweigh the risk associated with its use. Succinylcholine in lower doses is also used to treat laryngospasm.
Succinylcholine is contraindicated in patients after the acute phases of major trauma or burns, extensive denervation of skeletal muscle, upper or lower motor neuron injury, and severe infections, particularly clostridia, botulism, and tetanus, because succinylcholine in these patients may result in severe succinylcholine hyperkalemia and cardiac arrest.
The risk of succinylcholine hyperkalemia in these patients increases over time and usually peaks at 7 to 10 days after the injury, although the precise time of onset and the duration of the risk period are unknown.
It is also contraindicated in patients with a personal or family history of malignant hyperthermia or skeletal muscle myopathies and in patients with disuse atrophy because acute severe rhabdomyolysis may occur with subsequent succinylcholine hyperkalemia, ventricular arrhythmias, and cardiac arrest resulting.
The mechanism of succinylcholine hyperkalemia is related to its effect on muscle nicotinic acetylcholine receptors.
In the conditions at risk for succinylcholine hyperkalemia listed previously, there is an increase of muscle nicotinic acetylcholine receptors, which when depolarized by succinylcholine leads to efflux of intracellular potassium into the plasma, leading to acute hyperkalemia.
Alternative agents to avoid succinylcholine hyperkalemia are nondepolarizing agents such as vecuronium and rocuronium, but these do not result in as rapid a relaxation.