What are the anaesthetic considerations for a patient with a history of suxamethonium (sux) apnoea?

From the Guidelines

For a patient with a history of suxamethonium (sux) apnoea, it is crucial to avoid using suxamethonium and other depolarizing neuromuscular blocking agents completely, and instead, use non-depolarizing neuromuscular blocking agents such as rocuronium, vecuronium, or cisatracurium for muscle relaxation. This condition results from a genetic deficiency in plasma cholinesterase (pseudocholinesterase), which normally metabolizes suxamethonium 1. The most recent and highest quality study recommends using a fast-acting muscle relaxant such as rocuronium 0.9 to 1.2 mg kg-1 for rapid sequence induction (RSII) 1.

Key Considerations

• Rocuronium at 0.6-1.2 mg/kg is a good alternative for rapid sequence induction, as it provides excellent intubating conditions and can be rapidly reversed with sugammadex if needed 1.
• Document the condition prominently in the patient's medical records and alert the surgical team to ensure that suxamethonium is not used inadvertently.
• Consider testing family members as this is an inherited condition, and they may also be at risk of suxamethonium apnoea.
• The anesthetic plan should include standard monitoring plus neuromuscular monitoring to guide dosing and recovery from any muscle relaxants used.

Management

• If the diagnosis is uncertain, arrange for plasma cholinesterase level testing and dibucaine number determination to confirm the diagnosis.
• Recovery from suxamethonium apnea is spontaneous but may take hours, requiring continued ventilation and sedation until muscle function returns.
• Fresh frozen plasma (10-15 ml/kg) can be considered in emergency situations to provide exogenous cholinesterase, though this is rarely necessary with modern alternative agents available 1.

Alternative Agents

• Sugammadex is useful to reverse the effects of rocuronium, and a recent meta-analysis has shown that it shortens the mean time to obtain a TOF 0.9 and proceed with extubation compared with neostigmine or a placebo 1.
• Other non-depolarizing neuromuscular blocking agents such as vecuronium or cisatracurium can also be used as alternatives to rocuronium, depending on the specific clinical situation and patient factors.

From the FDA Drug Label

Due to the potential severity of these reactions, the necessary precautions, such as the immediate availability of appropriate emergency treatment, should be taken Risk of Death due to Medication Errors Administration of succinylcholine chloride results in paralysis, which may lead to respiratory arrest and death; GREAT CAUTION should be observed if succinylcholine is administered to patients during the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury

The anaesthetic considerations for a patient with a history of suxamethonium (sux) apnoea include:

• Great caution should be exercised when administering suxamethonium due to the risk of severe reactions, including respiratory arrest and death.
• Emergency treatment should be readily available in case of an adverse reaction.
• Alternative anaesthetic agents may be considered to avoid the risks associated with suxamethonium.
• Close monitoring of the patient's vital signs and respiratory status is essential during anaesthesia.
• Precautions should be taken to avoid hyperkalemia, malignant hyperthermia, and other potential complications associated with suxamethonium administration 2.

From the Research

Anaesthetic Considerations for Suxamethonium Apnoea

The anaesthetic considerations for a patient with a history of suxamethonium (sux) apnoea include:

• Avoiding the use of suxamethonium due to the risk of prolonged apnoea 3, 4
• Considering alternative muscle relaxants such as rocuronium for rapid sequence induction 5
• Careful pre-procedural assessment and consideration of potential sensitivities and adverse reactions associated with medications commonly used during procedures 4
• Measuring serum cholinesterase activity preoperatively to identify patients at risk of prolonged apnoea 3

Alternative Muscle Relaxants

Alternative muscle relaxants such as rocuronium may be used for rapid sequence induction, especially in patients with a history of suxamethonium apnoea 5.

• Rocuronium has been shown to be effective in prehospital emergency medicine, allowing for endotracheal intubation within 60 seconds 5
• The use of muscle relaxants can improve intubation conditions and avoid unnecessary high doses of anesthetics in hemodynamically unstable emergency patients 5

Preoperative Screening

Preoperative screening is crucial in identifying patients at risk of prolonged apnoea due to suxamethonium use 3, 4.

• Measuring serum cholinesterase activity preoperatively can help identify patients with pseudocholinesterase deficiency, which can increase the risk of prolonged apnoea 3
• A comprehensive pre-procedural assessment should be performed to gather crucial information about potential sensitivities and adverse reactions associated with medications commonly used during procedures 4