Do Neuromuscular Blockers (NMBs) stop seizures?

Neuromuscular Blockers Do Not Stop Seizures

Neuromuscular blocking agents (NMBAs) do not stop seizures; they only mask the clinical manifestations of seizures while the electrical activity in the brain continues. 1 This distinction is critically important for patient safety and appropriate management of seizure disorders.

Mechanism of Action and Implications

NMBAs work by:

• Blocking acetylcholine receptors at the neuromuscular junction
• Preventing muscle contraction without affecting brain electrical activity
• Masking the visible motor manifestations of seizures

This creates a dangerous situation where:

1. The seizure activity continues in the brain
2. The clinical signs become invisible to observers
3. Neurological damage may continue to occur

Appropriate Seizure Management

The correct approach to seizure management involves:

First-line treatment:

• IV Benzodiazepines (e.g., lorazepam 4 mg administered slowly at 2 mg/min) 2

Second-line treatment (if seizures persist):

• Levetiracetam IV (30-50 mg/kg at 100 mg/min) - 47-73% efficacy with minimal cardiopulmonary effects 2
• Valproate IV (20-30 mg/kg at 40 mg/min) - 46-88% efficacy, preferred in hemodynamically unstable patients 2
• Fosphenytoin/Phenytoin IV (18-20 mg/kg at 50 mg/min) - 56% efficacy 2

Refractory status epilepticus:

• Midazolam (8-20 mg bolus, followed by 4-30 mg/h infusion) 2
• Propofol (2 mg/kg bolus, followed by infusion of 5 mg/kg/h) 2
• Phenobarbital (10-20 mg/kg) - 58% efficacy 2

When NMBAs May Be Used in Seizure Patients

NMBAs may be used in specific circumstances for patients with seizures, but never as antiseizure treatment:

1. When intubation is required: To facilitate endotracheal intubation in patients with status epilepticus who need airway protection 1

2. For ventilator synchrony: In intubated seizure patients who have patient-ventilator dyssynchrony despite adequate sedation 1

3. For electroconvulsive therapy (ECT): To prevent injuries from motor manifestations of induced seizures 1

Critical Safety Measures When Using NMBAs in Seizure Patients

When NMBAs are used in patients with seizures:

1. Continuous EEG monitoring is mandatory: This is the only way to detect ongoing seizure activity when clinical manifestations are masked 1

2. Adequate sedation must be ensured: NMBAs provide no sedation or analgesia, and patients remain conscious and can experience pain and anxiety 1

3. Minimize duration: Keep NMBA use as brief as possible to allow for neurological assessment 1

4. Monitor depth of blockade: Use train-of-four monitoring to titrate to the minimum effective dose 1

Potential Complications of Inappropriate NMBA Use

Using NMBAs without appropriate monitoring and concurrent antiseizure treatment can lead to:

• Unrecognized ongoing seizure activity causing neurological damage
• Delayed diagnosis and treatment of status epilepticus
• Increased mortality and morbidity
• Psychological trauma if inadequate sedation is provided

Conclusion

NMBAs have no antiseizure properties and should never be used as a treatment for seizures. Their use in seizure patients should be limited to specific indications such as facilitating intubation or improving ventilator synchrony, always with concurrent appropriate antiseizure medications and continuous EEG monitoring.