Chest Management in Bulbar Motor Neuron Disease

Introduction to Chest Management

In patients with bulbar motor neuron disease, optimize secretion clearance and airway protection as the primary chest management strategy, recognizing that bulbar impairment significantly limits NIV tolerance and increases aspiration risk, often necessitating earlier consideration of invasive mechanical ventilation via tracheostomy 1, 2, 3

Start with oral anticholinergic medication as first-line therapy for sialorrhea control, continuing only if benefits outweigh side effects, and consider anticholinergic patch for longer-acting control as first- or second-line 1, 5
Escalate to botulinum toxin injections to salivary glands if anticholinergics fail or cause intolerable side effects 1
Implement lung volume recruitment (breath stacking) using handheld resuscitation bag or mouthpiece regularly for patients with reduced cough effectiveness, which requires caregiver training and assistance, and is more effective when combined with manually assisted cough 1, 6, 7
Add mechanical insufflation-exsufflation (MI-E/cough assist device) when alternative techniques cannot adequately improve cough effectiveness, which requires caregiver training and device availability, and is essential when secretion clearance becomes inadequate 1, 6

Trial NIV early in bulbar MND patients, but anticipate failure, and start NIV when hypercapnia develops—do not wait for acidosis, considering NIV even when normocapnic if vital capacity <1L and respiratory rate >20 2, 3, 4
Use controlled ventilation modes as triggering may be ineffective, and patients typically require low pressure support (8-12 cm H₂O pressure difference) 2, 3, 8
Do not delay intubation if NIV is failing, unless escalation to invasive ventilation is not desired by the patient or deemed inappropriate 2, 3, 4, 8

Perform pulmonary function tests every 6 months minimum, measuring FVC, MIP, and MEP, and screen for sleep disturbances at each visit as indicators of respiratory insufficiency 6
Use supplemental oxygen cautiously, as it corrects hypoxemia without treating underlying hypoventilation or atelectasis, and may impair central respiratory drive 5, 9

Screen for malnutrition at diagnosis and every 3 months, monitoring BMI and weight loss, and consider PEG when dysphagia develops 6

Place bulbar MND patients in HDU/ICU for NIV therapy given higher failure risk and potential for rapid deterioration, and initiate discussions about NIV, invasive ventilation, and resuscitation early as part of routine care 1, 2, 3, 4, 8
Involve senior staff and home mechanical ventilation specialists in advance care planning, discussing goals of care, potential institutionalization, and caregiver burden 1, 2, 3, 4, 8