Download Respiratory Management (Workshop) -Dr

Management of Respiratory
Complications of Motor
Neurone Disease (MND)
Dr Naveed Mustfa
University Hospital of North
Midlands (UHNM)
Introduction
Respiratory muscle weakness (RMW) in neuromuscular
disease (NMD)
• May be present at diagnosis
• Is progressive
•
•
•
•
Limb weakness affects symptoms
Subtle and insidious presentation
Symptoms can have multiple causes
Commonest cause of death
Respiratory Complications
• Inspiratory failure
– Inspiratory muscles
• Cough failure
– Oro-facial muscles, vocal cords and larynx
– Inspiratory and expiratory muscles
• Swallowing failure
Inspiratory Failure
Gas Exchange Apparatus and Ventilator
Pump - Components of the Respiratory
System
chest wall elasticity
lung elasticity
muscluar action
Ventilation Pump Failure Hypoventilation
• Respiratory muscle weakness
• Thoracic cage abnormality
(kyphoscoliosis)
• Reduced respiratory drive
– Drugs
– Cerebral, e.g. Head Injury
Muscles of Respiration
Inspiratory muscles
Expiratory muscles
neck musculature
external intercostal
diaphragm
internal intercostal
abdominal musculature
Lung Failure
shunt
diffusion impairment
ventilation/perfusion mismatch
Healthy Respiratory Muscle Pump
Adequate ventilation
Drive
Load
Capacity
Increased Load
• Can be caused by
– Exertion
– Lung failure (shunt, V/Q mismatch & diffusion)
– Mechanics (obstruction, reduced compliance)
• Initial hypoxia
• Increased respiratory rate & ventilation
• Subsequently type 1 respiratory failure
– hypoxia not corrected
– normocapnia or hypocapnia
• Eventually type 2 respiratory failure
– load too great to overcome
The failing respiratory muscle pump
Drive
Load
•Shunt, V/Q , Diffusion
•Supine posture, airways
obstruction, compliance
•Kyphoscoliosis, Obesity
Respiratory failure
Capacity
Reduced Capacity
• Caused by
– Respiratory muscle weakness
– Thoracic cage abnormalities
– Hyperinflation, air trapping
• Increased respiratory rate
• May have initial hypocapnia
• Type 2 respiratory failure
The failing respiratory muscle pump
Drive
•NMD
•Sleep (REM)
•Kyphoscoliosis
•Hyperinflation
Load
Respiratory failure
Capacity
Reduced Respiratory Drive
• Type 2 respiratory failure
The failing respiratory muscle pump
Drive
Respiratory depressants
Oxygen supplementation
Load
Respiratory failure
Capacity
The failing respiratory muscle pump
Drive
Respiratory depressants
Oxygen supplementation
•NMD
Load
•Sleep (REM)
•Shunt, V/Q , Diffusion
•Kyphoscoliosis
•Supine posture, airways
obstruction, compliance
•Hyperinflation
•Kyphoscoliosis, Obesity
Respiratory failure
Capacity
History of Respiratory Muscle
Weakness
Normal Breathing
Dyspnoea on Exertion
REM related sleep
disordered breathing (SDB)
Chest Infections
NREM and REM related SDB
Daytime Ventilatory Failure
Death
Symptoms of RMW in MND
• Dyspnoea (speech/eating/dressing)
• Orthopnoea
• Sleep fragmentation
•
•
•
•
dreams, nocturia, nightmares
wake non-refreshed with headache
daytime fatigue, somnolence, poor appetite
poor concentration/memory, hallucinations,
confusion
• Weak cough, choking and chest infections
• Symptoms may be absent or subtle
Signs of RMW in MND
•
•
•
•
•
Signs are often absent
Increased respiratory rate
Shallow breathing, reduced chest expansion
Weak cough and sniff
Abdominal paradox (inward movement of abdomen
during inspiration)
• Use of accessory muscles of respiration
• Moderate to strong correlations between QL and
Respiratory Muscle Strength (R = 0.42-0.82) Bourke et
al. Neurology 2001; 57: 2040-2044
Respiratory muscle tests in NMD
Non-invasive
Volitional
Vital Capacity
PI max,PE
max
Sniff Nasal
Invasive
Volitional
Sniff Poes
Sniff Pdi
Non-volitional Twitch Pdi
Non-invasive volitional
Lung Function
• Vital Capacity
• Available
• Repeatable
• Good serially
• But not discriminative in
•
•
early weakness
• Effort and mouth seal
dependent
Supine VC - > 20% fall
19-78% of predicted VC had
CO2 > 6 kPa
Maximal Static Pressures
• Portable and widely
available
• Non-invasive
• High values exclude
weakness
But……………
• Low values non-specific
• Difficult to make good seal
as disease progresses
Sniff Nasal Pressure
• Non-invasive
• Good measure of global
inspiratory muscle
strength
• Natural manoeuvre
• Still difficult in bulbar
patients
• Can be used serially
VC and SNIP compared
Lyall et al Brain 2001; 124: 2000-2013
Invasive Volitional
Invasive
• Oesophageal (Poes) and gastric (Pgas)
balloon catheters
• Transdiaphragmatic pressure (Pdi)
• Well tolerated, even in bulbar
• Not affected by transmission difficulties
• Stimulation of individual phrenic nerves for
non-volitional measurements, independent of
patient effort and technique
• Not widely available
Sniff Poes/Pdi
Pab
Pdi
Poes
20 cm H2O
1 second
Abdominal Paradox
Pab
30cmH2O
Pdi
Poes
1 second
• Most physiologically
‘pure’ method of
stimulating diaphragm
• Best (where possible)
for PNCT
But……….
•Supramaximality difficult and painful in clinically
•Low lower limit of normal (8 cm H2O)
•Potentiation confounds
•In fact few patient studies
Cervical Magnetic
Stimulation
Similowski et al J Appl Physiol 1989 :67; 1311-8
Other Magnetic Stimulation
Variants
Bilateral anterior magnetic stimulation
Anterior magnetic stimulation
Unilateral magnetic stimulation
MND patient
5 cmH2O
1 second
Pdi
Pgas
Poes
Normal Twitch Pdi
Other Investigations
• Oxygen saturation
• Blood gases
– if SpO2 92% in presence of lung disease
– if SpO2 94 % and no lung disease
– If PaCO2 > 6kPa refer for NIV
• Overnight oximetry
• Polysomnography
Management of Inspiratory
Muscle Weakness
Non-invasive Ventilation
•
•
•
•
Reduce work of breathing
Reduce airways collapse
Rest inspiratory muscles
Reduce load on system and increase capacity
• If patient cannot suck, use the machine to blow
NIV effects on survival
• Pinto et al, J Neurol Sci 1995; 129
– Sequential non-randomised & significant
improvement in survival
• Aboussouan et al, Ann Intern Med 1997; 127 and
Muscle and nerve 2001
– Retrospective and prospective review showing
significant survival in patients tolerating NIV
• Kleopa et al, J Neurol Sci 1999; 164
– 112 patients retrospectively reviewed
Effects of NIV on Quality of Life
• Kleopa et al, Pinto et al and Aboussouan et al
reported an improvement in symptoms with NIV
• Aboussouan 2001 Found a significant improvement in
the CRDQ Fatigue score (11 to 14.9, p=0.03)
• Lyall et al Neurology 2001; 57: 153-156 improvement
in Epworth sleepiness score and SF36
• Bourke, Bullock, Williams, Shaw and Gibson et al
Neurology 2003; 61: 171-177 improved sleep and
mental health for more than one year
NIV and MND (QL)
• Randomised but not blinded
• Prospective follow up before respiratory muscle
weakness
• 22 NIV and 19 Standard Care
• NIV better survival
• NIV improved SF 36 MCS and SAQLI symptom
domain and maintained at > 75% baseline
• Bulbar patients only sleep symptoms better
Bourke SC et al. Lancet Neurology 2006.
NIV, MND and Carers (QL)
• Despite increasing severity of MND and progressive
respiratory muscle weakness, NIV improves patient QL
within 3 months which is maintained long-term
• Carers experience increased levels of stress as MND
progresses but NIV does not seem to add to this burden
• Carer strain, emotion and low vitality may, in part,
account for failure to establish NIV
Mustfa, Walsh, Bryant, Lyall et al Neurology 2006; 66: 1211-1217
NICE 2016
NIV Information
–When to discuss NIV with person and care giver
•at diagnosis
•during respiratory monitoring or on function decline
•when person requests information
– Information to include
• symptoms and signs of respiratory muscle weakness
• purpose, nature and timing of respiratory function tests and
explanation of results
• NIV can improve symptoms and prolong life but does not
stop the progression of MND (or respiratory muscle
weakness)
NICE 2016
NIV Information
–Managing Breathlessness
•NIV pros and cons/use at different points of person’s lifetime
•Possibility of dependence
•Options for treating infections
•Recognising and coping with distressing situations
•Medication and psychological techniques
– Ensure person understands
•NIV treatment and other treatment options
•Need for regular review
•NIV compatibility with other equipment (eye gaze access
systems)
NICE 2016
NIV Information
–Stopping NIV
•Can be done anytime – even if 24 hour dependent
•Encourage to ask for assistance
•Medicines alleviate symptoms (guidelines exist – e.g. UHNM)
– Family and Carers
•Assess ability and willingness
•Address training needs
•Provide opportunity to discuss concerns
NICE 2016
Respiratory Function
– Perform tests every 2-3
months, depending on symptoms
and signs, patient preference
and rate of progression of MND
– Perform arterial or capillary
blood gas analysis if SpO2 is low
(92% if lung disease, 94% if
not)
– Refer urgently to a specialist
respiratory service if PaCO2 is
greater than 6 kPa to be seen
within 1 week and explain
Image reproduced by kind permission of
Motor Neurone Disease Association
NICE 2016
Respiratory Function
Discuss impact, referral and treatment options if:
Forced vital capacity
(FVC) or vital capacity (VC)

FVC or VC < 50% of
predicted value

FVC or VC < 80% of
predicted value plus any
symptoms or signs of
respiratory impairment,
particularly orthopnoea
Sniff nasal inspiratory pressure
(SNIP) and/or maximal inspiratory
pressure (MIP)



SNIP or MIP < 40 cmH2O
SNIP or MIP < 65 cmH2O for men or
55 cmH2O for women plus any
symptoms or signs of respiratory
impairment, particularly orthopnoea
Repeated regular tests show a rate
of decrease of SNIP or MIP of more
than 10 cmH2O per 3 months
NICE 2016
Non-invasive ventilation (NIV)
– offering a trial
– Offer a trial of NIV if symptoms
and signs and test results
indicate likely to benefit
– Discuss benefits and limitations
– In severe bulbar impairment or
severe cognitive problems, only
consider a trial if specific benefits
are possible
Image reproduced by kind permission of
Motor Neurone Disease Association
NICE 2016
NIV risk assessment & care plan
Before NIV, the multidisciplinary team to discuss with
person and family and/or carers to carry out and
coordinate patient-centred risk assessment
•NIV and interface and humidifier and power supply
•Accessing hospital and assistance and carers for infection and
ventilator failure
•Secretion management
•Travel including abroad – flight assessment
NICE 2016
NIV risk assessment & care plan
Before NIV, offer the patient and their family and carers
a copy of the care plan
• MDT and respiratory support
• Provision of carers and carer training
• Device maintenance and 24 hour technical/clinical
support
• Secretion and cough management
• Discussion on continuing or stopping treatment
NICE 2016
NIV – starting and reviews
– When starting NIV:
– initial acclimatisation during the day
– start regular treatment at night
– gradually build up hours of use
– Continue NIV if clinical reviews show
appropriate improvement
– Discuss all decisions to continue or
withdraw treatment with the patient,
and family and carers if patient agrees
Image reproduced by kind permission of
Motor Neurone Disease Association
NICE 2016
Patients with dementia
– Base decisions on respiratory function tests on considerations
specific to the patient’s needs and circumstances
– Before a decision is made on the use of NIV, the neurologist
from the multidisciplinary team should carry out an assessment
that includes:
– the patient’s capacity to make decisions and give consent
– the severity of dementia and cognitive problems
– whether the patient is likely to accept treatment
– whether the patient is likely to achieve improvements in
sleep-related symptoms and/or behavioural improvements
– a discussion with the patient’s family and/or carers
NICE 2016
Interfaces
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Mask
Nasal pillows
Lip seal
Mouthpiece
– underused
• Tracheostomy
– carer concerns, discharge destination
Cough Failure
Cough
• Maintain airway patency and prevent aspiration
• Adequate Inspiration
• Expiratory muscle strength -Pressures of 300cm
– Leeverson AM, The Thorax Marcel Dekker 1995:821-867
• Vocal cords and bulbar function
• Flows of 360-600 litres / min
– Leith DE, The Thorax Marcel Dekker 1997:545-602
Cough in NMD
• Inspiratory Muscle Weakness
• Bulbar Impairment -retaining inspiration
– Bach, Arch Phys Med Rehabil 1995
• Inability to minimise airway obstruction
– Garcia-Pachon, Thorax 1994; 49:896-900
• Expiratory Muscle Weakness
– Schiffman Chest 1993; 103:508-13, Serisier QJM 1982; 51: 205-
206
• Cough flow of 160 L/min for tracheostomy removal
• Cough flow of 255 l/min may have increased infections
Cough augmentation techniques
• Manually assisted cough
– Braun SR, American J of Phys Medicine 1984; 63:1-10
• Ambubag
– Bach, Chest 2000; 118:61-63
• Mechanical Insufflator- Exsufflator using
positive and negative pressures
– Beck GJ, Ann Intern Med 1954; 40:1081-94, Barach AL JAP
1955; 5:85-91
– But patients compliance is variable and not funded
• Breath stacking
– Bach et al
Cough in NMD
• Mucolytics
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Carbocisteine
Erdosteine
Saline and hypertonic saline nebulised
Pineapple juice
Cough in NMD
• Secretion reduction – swallow impairment
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Suction machines – not funded
Atropine eye drops for mouth
Anticholinergic patches or glycopyronium ingested
Amitriptyline
Ipratropium nebulized
Botox
Radiotherapy
Laryngotracheal separation
Swallowing Failure
Gastrostomy Insertion
• Respiratory muscle weakness (RMW) often
present at time of indication
• Be proactive - consider early PEG if before
significant RMW
• High procedural mortality if RMW
• PEG is safe if VC >50% & SNIP >40 & normal
oximetry & normal blood gas
• Otherwise RIG or PEG with NIV cover
• PEG with nasal endoscope
Fitness to Fly
BTS Guidelines
• SaO2 >95% or 92-95% and no risk factor =no
supplemental O2
• SaO2 92-95% and one risk factor =hypoxic challenge
• SaO2 <92%=supplemental O2
• Hypoxic Challenge
– PaO2 > 7.4 kPa = no O2
– PaO2 6.6-7.4 kPa = borderline, ?walk test
– PaO2 < 6.6 kPa = supplemental O2
SpO2 (air)
PaO2 (15%)
SNIP
FEV1
92%
6.5 kPa
15 cmH2O
53%
95%
7.0 kPa
35 cmH2O
86%
94%
6.0 kPa
22 cmH2O
50%
97%
7.7 kPa
50 cmH2O
74%
95%
7.8 kPa
70 cmH2O
100%
96%
7.7 kPa
unable
unable
96%
7.5 kPa
18 cmH2O
60%
98%
6.9 kPa
unable
71%
96%
8.1 kPa
unable
unable
97%
8.1 kPa
36 cmH2O
68%
Planning end-of-life care
Planning end-of-life care
– Offer to discuss end-of-life care with the patient
and (if the patient agrees) family and carers, at
an appropriate time and in a sensitive manner
to consider:
– planning
– advance decisions to refuse treatment
– what to do if NIV fails
– strategies to withdraw NIV if patient wants
– involvement of family and carers
Withdrawing NIV
• Consider when NIV is no longer
relieving symptoms and has begun
causing suffering
• Withdrawal for symptom control may
hasten death, but this is not the
purpose
• Patients and relatives to be warned of
potential of imminent death
Conclusions
• Respiratory muscle weakness (RMW)
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–
–
–
–
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subtle and insidious symptoms
commonest cause of death
reduces quality of life
causes cough impairment
can effect fitness for PEG
can effect fitness to fly
• RMW can be treated with NIV
– quality and duration of life improves in non-bulbar
patients, symptoms in bulbar patients
– bulbar patients and those with more stressed
carers less likely to tolerate
Conclusions
• Enlist help of palliative care physician
– advance directives allow patients wishes to be
respected and are strongly recommended
– planned approach to NIV withdrawal is required
– do not forget role of relatives and carers
• Cough can be augmented
• MDT
Thank you
Acknowledgements
• UHNM – Dr Ajit Thomas, Dr Martin
Allen, Ellen, Louise, Gill, Sue, Marie,
Gail, Dr Fiona Leslie, Tara and Joyce
• Kings – Professor Moxham, Professor
Leigh, Professor Chris Shaw, Professor
Polkey, Dr R Lyall, Tracey Flemming