Non-Invasive Ventilation in Myasthenia Gravis

Clinical Indicators for NIV Initiation

Myasthenia gravis patients should receive non-invasive ventilation when they demonstrate signs of respiratory distress with a PCO2 > 45 mmHg, forced vital capacity < 15-20 ml/kg, or oxygen saturation < 92% while awake, as recommended by the Centers for Disease Control and Prevention 1
Forced vital capacity (FVC) < 15-20 ml/kg or < 1 liter is an indicator for NIV initiation, according to the European Respiratory Society 2
Maximum inspiratory pressure (MIP) < 30 cm H2O is a criterion for NIV initiation, as stated by the Centers for Disease Control and Prevention 1
Maximum expiratory pressure (MEP) < 40 cm H2O is another indicator for NIV initiation, as recommended by the Centers for Disease Control and Prevention 1
Oxygen saturation < 92% while awake is a sign of respiratory distress that requires NIV, according to the American Thoracic Society 3, 4

Arterial blood gas analysis to evaluate PaO2, PaCO2, and pH is necessary for initial assessment, as recommended by the Centers for Disease Control and Prevention 1
Spirometry measurements including FVC, MIP, and MEP are required for initial assessment, according to the Centers for Disease Control and Prevention 1

Initial inspiratory positive airway pressure (IPAP): 8-12 cmH2O is recommended, as stated by the British Thoracic Society 7
Initial expiratory positive airway pressure (EPAP): 3-5 cmH2O is suggested, according to the British Thoracic Society 7
FiO2: Start at 40% and titrate to maintain SpO2 > 92%, as recommended by the American College of Chest Physicians 6

Intact bulbar function is a favorable factor for NIV success, as stated by the Centers for Disease Control and Prevention 1
Severe bulbar dysfunction with risk of aspiration is a risk factor for NIV failure, according to the Centers for Disease Control and Prevention 1

Select appropriate mask size and type to minimize air leakage and skin breakdown, as recommended by the British Thoracic Society 7
Consider alternating between nasal and full-face masks for prolonged use, according to the British Thoracic Society 7
Failure to improve after 1-2 hours of optimized NIV is an indication for intubation, as stated by the American College of Chest Physicians 6
Deteriorating level of consciousness is a sign that requires consideration of intubation, according to the British Thoracic Society 7

NIV should not be used in patients with severe bulbar dysfunction due to risk of aspiration, as recommended by the Centers for Disease Control and Prevention 1
Oxygen therapy alone should not be used to treat hypoventilation without ventilatory assistance, according to the American Thoracic Society 3, 4