In a myasthenic crisis, the diaphragm and intercostal muscles fail due to insufficient acetylcholine receptor activation. The immediate threat is hypercapnic respiratory failure and airway collapse, not merely dyspnea. The nurse's primary action is to prepare for definitive airway management—emergency intubation and mechanical ventilation—to ensure oxygenation and ventilation while pharmacologic interventions take effect. This follows the ABC (Airway, Breathing, Circulation) priority framework, where a compromised airway and ineffective breathing override all other interventions.
Key Actions:
- Assess Rapidly: Monitor vital capacity, negative inspiratory force, and single breath count. A vital capacity below 15-20 mL/kg or inability to count past 10-15 in one breath indicates impending respiratory arrest.
- Secure Airway: Have intubation equipment, suction, and a bag-valve-mask device at the bedside. Notify the rapid response team and respiratory therapy immediately.
- Support Breathing: Once intubated, mechanical ventilation rests the respiratory muscles while plasmapheresis or IV immunoglobulin and high-dose corticosteroids address the underlying crisis.
- Medication Safety: Hold anticholinesterase medications immediately before and after intubation to reduce secretions, then resume as ordered once the airway is secure.