Neuromuscular disease Flashcards
What are the 4 levels of pathologic injury in NMD?
Upper motor neuron
Lower motor neuron
Neuromuscular junction
Muscle
What is the normal response to oxygen desaturation vs the normal response to a decrease in PaCO2?
SpO2 = Linear, 1% decrease in sat = 1 L/m increase in minute ventilation
PaCO2 = Steep linear, 1 mmHg increase in PaCO2 = 2.5-3 L/m increase in MV
Describe how patients with NMD respond to changes in O2 sat and PaO2
Exhibit a significantly decreased response
Describe how mouth occlusion pressure is tested
Mouth occlusion pressure is tested by measuring the negative pressure produced during the first 100 milliseconds of inhalation with complete airway occlusion
How can respiratory drive be demonstrated?
Mouth occlusion pressure
What nerves innervate the muscles of expiration?
Lumbar
Intercostal
Why is mouth occlusion pressure an effective measure of respiratory drive?
It is measured so early in the breath that it cannot be voluntarily interfered with
Requires only a fraction of total muscle strength so it remains viable even in severely compromised patients
What nerves innervate the upper airways?
Glossopharyngeal
Vagus
Spinal accessory
Hypoglossal
What nerves innervate the muscles of inspiration?
Phrenic
Cervical
Intercostal
Spinal accessory
When does hypercapnia develop in relation to NIF score?
Once NIF declines to less than 30% of predicted, hypercapnia develops
What might a patient with NMD complain of besides dyspnea?
Fatigue
Poor sleep
Dyspnea on exertion
Why might a patient with a NMD develop sleep apnea?
Damage or disorders of the nerves may be more readily apparent at night when conscious control of breathing is absent and cannot compensate
Why can a patient with NMD develop decreased lung compliance?
Microatelectasis from reduced respiratory muscle strength \
Increases alveolar surface tension from low lung volumes
Sedentary lifestyle contributing to low tidal breaths
Why can the chest wall of a patient with NMD become stiff?
Chest wall structures such as tendons ligaments and costosternal articulations can grow stiff due to lack of physical movement from large breaths
What should be measured routinely in NMD patients in order to track the progression of the disease process?
Maximum inspiratory pressure
Maximum expiratory pressure
How can transdiaphragmatic pressure be measured?
Catheter with a balloon goes to mid esophagus (Pes), catheter with a balloon goes to (Pga) and the pressure difference is recorded to give us transdiaphragmatic pressure
In patient with diaphragmatic weakness, which position would be provide for a better FVC?
Upright
In patients with spinal cord injuries, which position would be better for providing a greater FVC?
Supine
What is the normal Pi max in men and women?
Men = -105 - -124 cm H2O
Women = -91 - –71 cm H2O
What is measured by measuring transdiaphragmatic pressure?
Diaphragmatic strength
What is the normal Pe max in men and women?
Men = 233 - 140 cm H2O
Women = 216 - 89 cm H2O
Define hemorrhagic stroke
Blood vessel weakened by aneurysm or arteriovenous malformation ruptures and spills blood into the brain
20% of all strokes
Define an ischemic stroke
80% of all strokes
Blood clot or plaque blocks off oxygen and nutrition to part of brain downstream of blockage
What is occurring in multiple sclerosis?
Demyelination of the central nervous system
What kind of respiratory problems could be caused by a stroke?
Loss of upper airway coordination resulting in aspiration
Loss of respiratory control resulting in either cheyne stokes breathing, apneustic breathing or ataxic breathing
An injury to what part of the spine will likely resulting in the need for chronic respiratory support?
C1-C3
An injury to what part of the spine will result in the preservation of diaphragmatic function?
C5-C6
What risks do patients with parkinson’s disease face?
Ventilatory failure
Upper airway obstruction
Aspiration
How does MS affect the respiratory system?
Respiratory muscle weakness
Bulbar dysfunction
Abnormalities in respiratory control
What upper airway difficulties do individuals with amyotrophic lateral sclerosis face?
Dysarthria
Layngospasm
Dysphagia
Risk for aspiration
Why is counseling for patients with ALS important?
Prepares them for what to expect as their disease progresses, allows for decisions regarding their care to be made ahead of time and allows them to understand options for ventilatory support
Where is the bacteria that causes tetanus found?
Found in the guts of many animals and is widely found in soil
Describe what is happening in a patient with Duchenne muscular dystrophy
Defective gene on X chromosome
Gene is responsible for production of dystrophin
Lack of dystrophin results in damaged muscles that lose functionality
How does tetanus affect muscle control?
Bacteria secrete a toxin that inactivates inhibitory neurotransmission resulting in the muscle being unable to “turn off”
Why do patients with tetanus need to be sedated and mechanically ventilated?
Sedation controls the muscle spasms but inhibits breathing
Patients may spend weeks on vent and be trached
What kind of training can be performed by patients with NMD to train their respiratory muscles?
Devices that set a resistive load for inhalation
Studies do not show improved outcomes
What peak flow indicates a need for assisted cough?
Less than 160 L/m
Describe a quad cough
Basically a manual cough assist
What maneuvers can patients perform in order to remain independent from mechanical support for short periods of time or build up enough volume for a sufficient cough?
Breath stacking
Manual resuscitator
Frog breathing/glossopharyngeal breathing
What is another option for assisting patients cough?
Mechanical insufflator-exsufflator
Provides positive pressure during inhalation, negative pressure during exhalation to aid cough
What factors favor NIV for NMD patients?
Awake and cooperative patient
Good control of airway
Has minimal secretions
Maintains hemodynamic stability
What factors favor invasive ventilation in NMD patients?
Copious secretions
Poor airway control
Doesnt tolerate NIV
Sufferes from impaired cognition
Maintains unstable hemodynamics
How should patients with spinal injuries be ventilated?
Ventilated with large tidal volumes, 10-15 ml/kg
What are the benefits associated with diaphragmatic pacing?
Allows some patients to come off of ventilator
What are the downsides of diaphragmatic pacing?
Associated with increased risk of mortality in ALS patients
Expensive
Potential for sudden hardware failure
Possible for upper airway to become obstructed after tracheotomy closes
Can induce diaphragmatic fatigue
