Pulmonary managementof the neuromuscular patient

Tim Short, MBA, BS, RRT

This program has been approved for 1 hour of continuing education credit.

Objectives

• Discuss management of patients with Amyotrophic Lateral Sclerosis (ALS)

– Secretion removal– Noninvasive ventilation– American Academy of Neurology (AAN) practice parameters

• Review the mechanics of airway clearance• Identify conditions that benefit from secretion mobilization and/or

secretion removal– Intrinsic disease– Neuromuscular disease

• Discuss techniques that may be used for airway clearance

Neuromuscular disease

• Mucociliary transport is often normal

• Amyotrophic Lateral Sclerosis (ALS) is a progressive neuromuscular disease that affects nerve cells in the brain and the spinal cord

• Patients with neuromuscular disease have an impaired ability to eliminate secretions

• It may be due to

• Lack of respiratory muscle strength

• Impaired ability to coughALS is often referred to as

"Lou Gehrig's Disease"

• 50 percent die within three years of disease onset

• 80 percent die within five years of diagnosis

• 10 percent live more than 10 years

NIV has prolonged the length of survival by treating the respiratory insufficiency.

• ALS occurs in all races

• 1.5 to 1.0 ratio of men to women

ALS statistics

ALSLung disease

When ALS affects the neurons that control the respiratory muscles, breathing becomes strained or weak

Begins with shortness of breath during exercise or at night

15 percent never have a breathing problem

In the past, diminished breathing was the usual cause of death.

Now, there are options.

Living with ALS: Adapting to Breathing Changes, 1997, ALS Assoc.

Patient care strategy

Offer a comprehensive approach to the management of the ALS patient in the home.

• Utilize a bi-level S/T ventilatory support system

• Utilize compliance reporting systems and the device report

• Provide additional therapies as needed

• This allows for identification of patients early in the disease process, and for the provision of appropriate therapies for patient management throughout the course of the disease

Lung disease

• Mucociliary transport is often compromised

• Increased sputum production is a result of intrinsic lung disease

• Patient has intact muscle strength for strong coughing

Groups at risk for retaining secretions

• Intrinsic lung disease– Cystic Fibrosis (CF), COPD, bronchiectasis

• Neuromuscular disease – ALS, muscular dystrophy, post polio, multiple

sclerosis, spinal muscular atrophy

– Spinal cord injury, stroke

• Mucus production

• Biochemical changes

Inhaledirritant

Inflammatoryresponse

Ineffectiveairway

clearanceRetained

secretions

Obstruction

Lungdamage

Airway clearance cycle

Approximately 90% of episodes of respiratory failure within patients with neuromuscular disease occur during otherwise benign upper respiratory infections because of the inability to clear the airways.

Tzeng AC. Bach JR. Prevention of pulmonary Morbidity for Patients with Neuromuscular Disease. Chest. November 2000:Vol. 118, No. 5; 1390-6

Impact of ineffective cough

AAN practice parameters

The Care of the Patient with Amyotrophic Lateral Sclerosis (an evidence-based review)

American Academy of Neurology (1999)

Respiratory Work Group

• Deborah Gelinas, MD

• Edward A Oppenheimer, MD

AAN practice parameters

Five areas of investigation

• Breaking the news

• Symptomatic treatment

• Nutrition

• Respiratory insufficiency and mechanical ventilation

• Advance directives and palliative care

AAN practice parameters

Principles of ALS management

• High priority should be placed on patient autonomy

• Information is appropriately timed for decision-making

• Address the full continuum of care

• Advance directive discussions should be introduced and re-evaluated by the physician

AAN practice parameters

Pulmonary measurements

• Erect sitting vital capacity

• Supine vital capacity

A decrease in VC to 50 percent is associated with respiratory symptoms

• Nocturnal oximetry

• Polysomnogram

Measuring cough strength

• Maximum expiratory pressure

– Isolates cough muscle strength

– MEP of 60 cm H2O and higher has been shown to

correlate well with the ability to generate adequate cough flows

• Peak cough flow

– Simple testing format

– Peak flow meter and mask

– Measure Peak Cough Flow (PCF)

– Normal: 6-12 l/s or 360–720 l/min

Ineffective cough

• Respiratory muscle strength can deteriorate during respiratory infections

• PCF between 160 l/minute but less than 270 l/min are also at risk

• For this reason, a PCF of 270 l/min has been used to identify patients who would benefit from assisted cough techniques

Bach J, Ishikawa Y, et al. Prevention of pulmonary morbidity for patients with Duchenne muscular dystrophy. Chest 1997;112 (4):1024-28

Ineffective cough

• PCF < 160 l/min

– Increases risk of respiratory infection

– Introduces risk of chronic lung damage as a result of recurring lung infection

– Increases risk of pneumonia and resulting hospitalizations

Airway clearance therapies

What to use?

Understanding airway clearance methods

• Secretion removal

Techniques that mobilize and remove secretions from the lungs

• Secretion mobilization

Techniques designed to loosen and mobilize secretions from the lower airway to the upper airway

Secretion clearing/removal techniques

– Suctioning

– Manually assisted cough (MAC)

– Mechanical insufflation-exsufflation (MI-E)

Secretion mobilization techniques

Manual chest physiotherapy and postural drainage External percussion and vibration devices High frequency chest wall oscillation (HFCWO) Aerosol therapy Positive expiratory pressure devices (PEP) Intrapulmonary percussive ventilation (IPV)

Effective cough needed to clear mobilized secretions

Secretion mobilization techniques

“...are effective in mobilizing retained mucous secretions for patients with sick lungs (intrinsic), such as CF and COPD, although these devices will not help a patient whose main problem is impaired cough clearance.”

Finder, JD. Review of Airway Clearance Technologies 2006. RT Magazine July 2006 22-25.

Mechanical insufflation-exsufflation (MI-E)

• Assists patients to clear retained secretions noninvasively

• Applies a positive pressure to the airway (insufflation) followed by a rapid shift to a negative pressure (exsufflation) simulating a cough

• May be applied by mask or mouthpiece or invasively via endotracheal or tracheostomy tube

Indications for use for Cough Assist

Any patient unable to cough or clear secretionseffectively due to reduced peak cough expiratoryflow < 270 l/min

Contraindications

• History of bullous emphysema• Known susceptibility to pneumothorax or pneumo-

mediastinum• Recent barotrauma

Benefits of insufflation

Neuromuscular disease - reduced VC and Vt and an inability to sigh that result in developing atelectasis and pneumonia1

Provides normal hyperinflation - has been shown to combat loss of chest wall

compliance and microatelectasis2

1 Estenne M. et al. Lung volume restriction in patients with chronic respiratory muscle weakness: the role of microatelectasis. Thorax 1993:48(7):698-7012 Estenne M. et al. Chest wall stiffness in patients with chronic respiratory muscle weakness. Am Rev Respir Dis 1983;128(6):1002-1007

Benefits of exsufflation

• Flow simulates a natural expiratory cough flow (6-10 l/sec)

• More effective than invasive suctioning since suctioning has been shown to miss the left mainstem bronchus 90% of the time1

• Potentially eliminates the need for invasive suctioning

1 Bach Jr. Room For Imagination:Inspiratory and expiratory muscle aids. Advance. April 2006: 58-60

Inhale + Exhale + Pause = Cycle

Rest 20-30 seconds

Repeat sequence 4-6 times

Repeat cycle 4-6 times

MI-E treatment

Typical MI-E settings

• Pressures (positive and negative)– Start low, 10 to 15 cm H2O

– Get patient acclimated to device

– Increase pressures as tolerated, 35 to 45 cm H2O ideally1

• Times (inhale, exhale and pause)– Small children: 1 to 2 sec

– Adults: 2 to 3 sec

1 Gomez-Marino E et al.Mechanical insufflation-exsufflation. Pressure,volume, and flow relationships and the adequacy of the manufacturer’s guidelines. Am J Phys Rehabil 2002;81(8):579-583.

Settings

• The goal of inspiratory pressure is to give the patient a good hyper-expansion

• The goal of expiratory pressure is to replace a good expiratory cough flow

• Pressures and times vary with each patient

Settings

• Important to work with patient to find settings which are both comfortable and effective

• Studies have shown that therapeutic PCF may not be reached with MI-E expiratory pressures less than -40 cm H2O

Clinical benefitsMean peak cough expiratory flow rates of 21 patients with NMD studied

– Unassisted 1.81 ± 1.03 L/sec

– Assisted cough 4.27 ± 1.29 L/sec

– MI-E & MAC 7.47 ± 1.02 L/sec

(Normal PCF is 6-12 L/sec)

Conclusion: In-exsufflator cough machine improved peak cough expiratory flow rates

Bach J. Chest 1993; 104:1553.

Therapy combination benefits

0

2

4

6

8

10

Unassisted MI MI + MAC MI-E+MAC

MI-E & MAC produced the most effective cough flows

Bach et al: Chest, 1993; 104:1553-62.

Noninvasive ventilation

ALSLung disease during sleep

Weakened bulbar muscles can cause closing of the airway

Nerve and muscle functions relax during sleep causing under- ventilation

• With complaints of morning headaches, lethargy, and SOB

Early recognition of weakening muscles during REM sleep by:

• PSG

• Overnight oximetryLiving with ALS: Adapting to Breathing Changes, 1997, ALS Assoc.

AAN practice parameters

Early indications of respiratory insufficiency

• Dyspnea on exertion

• Supine dyspnea

• Fatigue

• Disturbed sleep

• Morning headaches

Noninvasive ventilation should be initiated with the onset of symptoms

AAN practice parameters

NIV benefits to the patient

• Improves the symptoms of hypoventilation

• Improves quality of life

• Increases survival by treating the respiratory insufficiency

Allows for decision making on more advanced care

AAN practice parameters

Recommendations

• Be vigilant for hypoventilation symptoms

• Offer noninvasive ventilatory support

• Offer invasive ventilatory support

• Respect the right of the patient to refuse therapy

• When withdrawing ventilation, relieve dyspnea and anxiety

• The committee strongly supports the use of mechanical insufflation-exsufflation in patients with DMD

• Patients with DMD should be taught strategies to improve airway clearance and how to employ those techniques early and aggressively

• Use assisted cough technologies in patients whose clinical history suggests difficulty in airway clearance, or whose peak cough flow is < 270 l/min and/or whose maximal expiratory pressures are < 60 cm H2O

Quality of life

Study aimInitiation of NIV earlier than current “standard of care” may provide additional benefits in terms of respiratory function and quality of life.

Jackson et al. A Prospective Evaluation of Pulmonary Function Studies and Symptoms of Hypoventilation in ALS/MND Patients. J Neurol Sci 2002;1610

Quality of life

13 patients

7 received early NIV intervention, 6 received NIV per existing standard of care

FVC was done in sitting or supine position

Pulse oximetry was performed

Quality of life

Conclusions

• To detect respiratory insufficiency, O2 saturation of

less than 90 percent is a more sensitive indicator than FVC of 70 percent

• Early intervention with NIV increased “vitality” subscale of the SF-36

• NIV earlier than current practice may result in improved QOL

BiPAP in OSA with other co morbidities – AVAPS

OSAOSA

Neuro-Neuro-Muscular Muscular DisordersDisorders

COPD – COPD – OverlapOverlap

Obesity Hypo-Obesity Hypo-Ventilation Ventilation

AVAPS

AVAPSAVAPS

• AVAPS is the treatment of choice for patients presenting with chronic respiratory disease as well as a mixed SDB pathology.

• AVAPS automatic ventilation modality allows normalizing ventilation with a target exhale Vt whereas the EPAP level maintains the UA open (treating OA).

• The settable backup rate and the rise time allows better control and adaptation to different types of patients.

AVAPS Algorithm

• AVAPS is a ventilation device for patients with respiratory insufficiency

• ST-T-CP modes can treat central apneas

• AVAPS: Pressure Support adjustment looking at average tidal volume

– PS increase or decrease maximum speed is 1 cm H2O/minute

– AVAPS allow maintaining a target tidal volume

+1 cmH2O/min MaxIPAP Max.

IPAP Min.

BiPAP Synchrony AVAPS

10 PM 7 AM

EPAP

Target

Vt

-1 cmH2O/min Max

Patient tracing over time

• Automatically adjusts IPAP to guarantee a target tidal volume

S/T compared to S/T + AVAPS

Pressure support is progressively decreasing: • AVAPS follows patient’s needs and disease progression• The patient is getting better

Clinical benefits of AVAPS

• Guarantee of ventilatory support during progressive ventilatory changes of the patient

• Guarantee of ventilatory support during positional changes during sleep

• Provides the assurance of a tidal volume within a bilevel system

• Alarms to indicate that tidal volume is not being maintained

Summary

• Secretion mobilization techniques assist the mucociliary escalator, but they do not assist cough

• Cough is the principle mechanism for clearing the airways

• Patients who have an impaired cough mechanism require secretions to be removed

• Initiation of NIV may improve quality of life and symptoms of hypoventilation in patients with neuromuscular disease