Investigations

• Investigations:

  • the problem for neurological patients is inspiration due to respiratory muscle weakness, so it is a restrictive defect

  
• Lung Function Testing for neurological patients:

  • decrease in FEV1
  • decrease in FVC
  • FEV1/FVC% (which is normally 80%) is normal or increased
  • vital capacity must be measured daily to monitor progress in acute scenario e.g. GBS
  • If vital capacity falls less than 1 L (less than 15ml/kg bodyweight) may require intubation and ventilation
• Respiratory Muscle Strength for neurological patients:

  • Maximum Inspiratory and Expiratory Mouth Pressure (MIP/MEP) - measures inspiratory and expiratory muscle strength
  • Sniff Nasal Inspiratory Pressure (SNIP)
• Peak Cough Flow Measurements:

  • Should be measured regularly in patients with neuromuscular disease
  • Reduced peak cough flow (PCF) leads to ineffective airway clearance and will accelerate the development of respiratory failure and death
  • A peak flow cough more than 160 L/min is necessary to clear secretions effectively
  • Peak cough flow is how fast the air comes out when the patients cough, if its slow it suggests a weak cough due to weak expiratory muscles, so not able to clear secretions, accelerating respiratory failure and death
  • can use a peak flow meter to measure peak flow cough