1. SEAT Physiotherapy Study Day
Thursday 10th November 2011
COMPLEX NEURODISABILTY AND NEUROMUSCULAR DISEASE: Respiratory Management and Investigations
Don Urquhart MD, MRCPCH
Consultant in Paediatric Respiratory and Sleep Medicine
Royal Hospital for Sick Children
Edinburgh 1

2. OBJECTIVES Complex Neurodisability Neuromuscular Disease
Scenarios where assessment required
Assessment options
Management of acute and chronic respiratory deterioration in children with complex neurodisability
Neuromuscular Disease
Methods of assessment
From what age?
Management of respiratory failure
Child-centred approach 2

3. COMPLEX NEURODISABILITY Assessment
Scenarios where assessment required
Acutely unwell/respiratory deterioration
Prior to major surgery i.e. scoliosis
Sleep-disordered breathing/obstruction

4. COMPLEX NEURODISABILITY Acutely UnwellRD
6 year old girl
Chromosomal anomaly
Severe developmental delay
Increased work of breathing
SpO2 87% on room air

5. COMPLEX NEURODISABILITY Acutely Unwell
What investigations would you order?
What treatment options might you consider?

6. COMPLEX NEURODISABILITY Acutely Unwell
What investigations would you order?
Chest X-ray
Blood gas

7. CHEST X-RAY

8. CHEST X-RAY
Dense LLL collapse

9. BLOOD GAS
Blood gas:
pH 7.22
pCO2 10.3
Bicarbonate 36
BE +13

10. COMPLEX NEURODISABILITY Acutely Unwell
What investigations would you order?
What treatment options might you consider?

11. COMPLEX NEURODISABILITY Acutely Unwell
What treatment options might you consider?
Antibiotics
Oxygen
Physiotherapy
Mucolytic agents
Ventilatory support

12. COMPLEX NEURODISABILITY Acutely Unwell
Antibiotics
Based on previous or known cultures
Oxygen
Physiotherapy
Mucolytic agents
Ventilatory support

13. COMPLEX NEURODISABILITY Acutely Unwell
Antibiotics
Oxygen
May need to limit flow in setting of type II failure
Physiotherapy
Mucolytic agents
Ventilatory support

14. COMPLEX NEURODISABILITY Acutely Unwell
Antibiotics
Oxygen
Physiotherapy
Secretion management
Airway clearance
Mucolytic agents
Ventilatory support

15. COMPLEX NEURODISABILITY Acutely Unwell
Antibiotics
Oxygen
Physiotherapy
Mucolytic agents
DNase
Hypertonic saline
N-acetyl cysteine
Ventilatory support

16. COMPLEX NEURODISABILITY Acutely Unwell
Antibiotics
Oxygen
Physiotherapy
Mucolytic agents
Ventilatory support
Prior to physiotherapy to augment airway clearance
Bi-level ventilation to assist ventilation

17. COMPLEX NEURODISABILITY Pre-operative scoliosis work-up
Scoliosis in a healthy child
Pre-op work-up would include:
Lung Function Testing
Exercise Capacity
Clinical evaluation

18. COMPLEX NEURODISABILITY Pre-operative scoliosis work-upRJ
Quadriplegic Cerebral Palsy
Epilepsy
Global developmental delay
Progressive neuromuscular scoliosis
How do we obtain a functional lung assessment
on which to estimate risk of major surgery?

19. COMPLEX NEURODISABILITY Pre-operative scoliosis work-up
Sleep Study:
During sleep have falls in both respiratory rate and also tidal volume (i.e. reduced VE)
Relative hypoventilation vs. awake
Respiratory system under stress
Blood Gas: - Indicator of any CO2 retention
Chest X-ray:
- Evaluate lung fields for parenchymal change

20. COMPLEX NEURODISABILITY Pre-operative scoliosis work-up
Sleep Study:
Average SpO2 96%.
No significant obstructive or central events were witnessed.
Blood Gas:
pH 7.39
pCO2 5.5
BE -0.5

21. CHEST X-RAY

22. CHEST X-RAY
Thoracolumbar scoliosis
Small volume lung fields

23. COMPLEX NEURODISABILITY Upper Airways ObstructionJB
6-year old boy
Cerebral palsy
Night-time snoring ++
Frequent arousals
Fragmented sleep
Poor concentration at school

24. COMPLEX NEURODISABILITY Upper Airways Obstruction
Admitted ward 1
Sleep Study arranged

25. SLEEP STUDY 25

26. OBSTRUCTIVE SLEEP APNOEA26

27. OBSTRUCTIVE SLEEP APNOEA
Clusters of SpO2 27

28. OBSTRUCTIVE SLEEP APNOEA
Hypopnoea
Hypopnoea
Hypopnoea 28

29. OBSTRUCTIVE SLEEP APNOEA What treatment can we offer?
75-100% improve with T&A’s
AAP Technical Report
Schechter et al. Pediatrics 2002
Success rates much lower if comorbidities
CPAP therapy
Airway adjuncts
Waters et al. Am J Respir Crit Care Med 1995 29

30. OBSTRUCTIVE SLEEP APNOEA Post-adenotonsillectomy30

31. COMPLEX NEURODISABILITY Acute Upper Airways ObstructionJG
10-year old boy
Unwell child with pneumonia
Secretions +++
Clamps shut mouth on suctioning
Episodic (but frequent and profound SpO2)
Any ideas?

32. NP AIRWAY 3 32

33. NP AIRWAY Bypass obstruction Conduit for suction
Tip sits in oropharynx
Conduit for suction
Facilitates airway clearance
PS: Beware the blocked NPA!
Worse than having no adjunct 3 33

34. NEUROMUSCULAR DISEASE
Manifold setting of conditions including:
Muscle diseases
e.g. myopathies, muscular dystrophies
Nervous system disorders
e.g. Spinal muscular atrophy
Myotonic dystrophy
Etc.

35. NEUROMUSCULAR DISEASE
Illustrative condition chosen = DMD
Duchenne Muscular Dystrophy
X-linked disease affecting 1 in 3000 boys
Mutation in dystrophin gene (Xp21)
‘Dystrophin’ is essential protein for muscle structure
Progressive and relentless muscle weakness
Weakness begins in first decade
Wheelchair-bound by aged 10 years
Respiratory muscle weakness by aged years
Poor cough clearance predisposes to infection
Eventual compromise to ventilation during sleep

36. NEUROMUSCULAR DISEASE
Methods of assessment
From what age?
Management of respiratory failure
Child-centred approach

37. DUCHENNE MUSCULAR DYSTROPHY Methods of assessment
Lung Function
Respiratory Muscle Pressure
Cough Peak Flow
Sleep Study

38. DUCHENNE MUSCULAR DYSTROPHY Methods of assessment
Lung Function
Respiratory Muscle Pressure
Cough Peak Flow
Sleep Study

39. SPIROMETRY 39

40. SPIROMETRY FLOW-VOLUME LOOP
Allows us to measure lung capacity and airflow 40

41. SPIROMETRY RESPIRATORY MUSCLE WEAKNESS:
Reduces ability to forcibly exhale with reduced airflows and also reduced lung volumes. 41

42. SPIROMETRY Why do we do it?
Measure lung volumes
Measure changes in lung volumes over time
Can be reliably performed in those aged >5 years
SPIROMETRY IS A SURROGATE MEASURE OF RESPIRATORY MUSCLE STRENGTH 42

43. DUCHENNE Lung Function
Restrictive lung disease pattern
Decreases in TLC and VC closely linked to level of muscle weakness
Change in VC is important
Track changes in lung function in DMD from aged 10 onwards

44. RESPIRATORY MUSCLES What are they? What can we measure?
What do the measurements mean?

45. A B C F D E G H I E N X S P P I R R A A T T O O N Sternocleidomastoid
Scalenes I N S P R A T O E X P I R A T O N
External
intercostals C
Internal
Intercostals F D
Parasternal
Intercostals
External
abdominal
oblique E
Diaphragm G
Name these muscles
Which side shows the muscles that are involved in inspiration?
Rectus
abdominus H

46. RESPIRATORY MUSCLES What are they? What can we measure?
What do the measurements mean?

47. RESPIRATORY MUSCLES What can we measure?
Inspiratory muscle pressure monitoring
Sniff Inspiratory Pressure [SnIP]
Mouth Inspiratory Pressure [MIP] aka Pimax
Expiratory muscle pressure monitoring]
Mouth Expiratory Pressure [MEP] aka Pemax
Cough peak flow

48. RESPIRATORY MUSCLES What can we measure?
ATS/ERS statement on respiratory muscle testing.
Am J Respir Crit Care Med 2002; 166:

49. RESPIRATORY MUSCLES MIP/MEP methods
Maximal pressure measured as average over 1 second around peak pressure
MIP
MEP

50. RESPIRATORY MUSCLES SnIP methods
Sniff nasal inspiratory pressure (SNIP) measures, from FRC, the nasal pressure in an occluded nostril during a maximal sniff
Values in healthy children similar to healthy adults
SNIP 104+/-26 cmH2O in boys
SNIP 93+/- 23 cmH2O in girls

51. RESPIRATORY MUSCLES Peak cough flow
Reduced cough strength predisposes to viral respiratory tract infection and pneumonias
Reductions in VC and in expiratory muscle strength reduce cough strength

52. RESPIRATORY MUSCLES Peak cough flow
Can be done by parent or physio
Measured with peak flow meter
Maximal inspiration followed by a cough
Peak Cough Flow > 160L/min is needed to clear secretions

53. RESPIRATORY MUSCLES What are they? What can we measure?
What do the measurements mean?

54. RESPIRATORY MUSCLES What do the measurements mean?
REFERENCE VALUES
Maximal pressures increase with age
Males > Females - even prior to puberty
MIP > 80 cmH2O excludes inspiratory muscle weakness
Lower values difficult to interpret as test is effort dependent

55. RESPIRATORY MUSCLES What do the measurements mean?
Normative data exists for children:
Rafferty GF, Leech S, Knight L, Moxham J, Greenough A.
Sniff nasal inspiratory pressure in children.
Pediatr Pulmonol 2000; 29:
Stefanutti D, Fitting.JW.
Sniff inspiratory muscle pressure. Reference values in Caucasian children.
Am J Respir Crit Care Med 1999; 159:

56. RESPIRATORY MUSCLES What do the measurements mean?
Which test of inspiratory strength?
SnIP easier to perform than MIP
SnIP on average reads 14cm H20 higher than MIP
Rafferty et al. 2000
Which test of expiratory strength?
MEP provides more information than cough peak flow
Easy to perform in children used to spirometry
Peak Cough Flow > 160L/min is needed to clear secretions

57. SLEEP STUDY 57

58. SLEEP STUDIES Airflow and effort ceased or reduced = central event
This is type of event that occurs with muscle weakness 58

59. SLEEP STUDIES Why do we do them?
Measure oxygen levels at night
Measure waste gas (carbon dioxide clearance)
Are useful in detecting obstruction that might be easily treated by taking out tonsils and adenoids
Are a vital early warning sign of respiratory failure, because respiratory muscle weakness is more manifest at night
SLEEP MEASUREMENTS ARE AN EARLY WARNING SYSTEM FOR DETECTING RESPIRATORY MUSCLE WEAKNESS 59

60. SLEEP STUDY Eventual resp. muscle weakness in DMD Hypoventilation:
- Leads to respiratory failure
- Surveillance for any evidence of under-breathing (hypoventilation) on sleep study
Hypoventilation:
Failure to maintain normal gas exchange
Can be corrected with non-invasive ventilation

61. SLEEP STUDY – Duchenne
Fall in SpO2 and rise in tcCO2 in REM sleep

62. LONG-TERM VENTILATION62

63. NIV TITRATION – Night 1
Pressure 10/5
Pressure 12/5

64. NIV TITRATION – Night 2 Gradual  pressure from 12/5 to 14/5 then 16/5

65. Sullivan CE et al. Lancet 1981.
DEVELOPMENT OF NIV
Sullivan CE et al. Lancet 1981.
Reversal of obstructive sleep apnoea by continuous positive airway pressure applied through the nares. 65

66. CPAP Continuous Positive Airways Pressure Used to treat obstruction
Provides compressed air delivered via a hose and mask 66

67. BiPAP 1987 Ellis et al. Am Rev Respir Dis - First report of NIPPV
NIPPV (BiPAP) now used to Rx hypercapnic respiratory failure
- CPAP can overcome obstruction
Need bi-level ventilation to overcome respiratory pump insufficiency
May need rate to overcome a lack of central drive 67

68. BiPAP IPAP (Inspiratory Positive Airway Pressure)
EPAP (Expiratory Positive Airway Pressure)
Rate
Mode (S/T, Timed, Spontaneous i.e. no rate)
Rise Time (Time to achieve pressure)
I:E Ratio 68

69. CONSENSUS GUIDELINES – 13 years ago
“ At present, nasal mask ventilation in young children must be considered an investigational technique for research and/or use only be experienced centres. Further to our knowledge, there are no published reports on the use of this technique in small children, there are no generally accepted guidelines”
Make BJ. Mechanical ventilation beyond the intensive care unit: report of a consensus conference of the American College of Chest Physicians. Chest 1998 69

70. VENTILATED CHILDREN IN THE UK The past 20 years
Wallis et al. Arch Dis Child 2011

71. DUCHENNE MD How does NIV help?
Treat chronic hypercapnic respiratory failure
Control nocturnal hypoventilation
Improve gas exchange
Offload (rest) respiratory muscles
Improve daytime functioning
Palliate symptoms
Improve quality of sleep
Improvement in quality of life

72. DUCHENNE MD Respiratory Care
Non-invasive ventilation (NIV) has been key to survival in DMD
Survival following institution of NIV at 1 year was 85% and at 5 years was 73% [Royal Brompton Hospital data]
Simonds et al. Thorax 1998 72

73. DUCHENNE MD Respiratory Care
Non-invasive ventilation has been key to survival in DMD
Chances of surviving to >25 years
0% in 1960s
4% in 1970s
12% in 1980s
53% in those ventilated since 1990
Eagle et al. Neuromusc Disord 2002 73

74. From: Eagle et al. Neuromusc Disord 2002
NB: 1990s cohort includes those who had NIV and those who did not. If ventilated group is removed, no survival differences seen between 1980s and 1990s cohorts 74

75. Dramatic illustration of beneficial effects of NIV
From: Eagle et al. Neuromusc Disord 2002
Dramatic illustration of beneficial effects of NIV 75

76. Scottish Muscle Network
INTEGRATED CARE MODEL
Scottish Muscle Network
Co-ordinated approach to care
Early diagnosis
Ambulant and non-ambulant stages of care
Pathways for end of life management
Scottish Muscle Network 76

77. INTEGRATED CARE MODEL Child with DMD Neurology Genetics School/ Family
Social Work
PhysioRx
Child with DMD
O.T.
Spinal Sx
Cardiology
Nutrition
Respiratory 77

78. INTEGRATED CARE MODEL Edinburgh experience
Past 9 months clinic running at Braidburn School
Multidisciplinary clinic
Consultant in Neurodisability (Dr Alex Baxter)
Consultant in Clinical Genetics (Dr Cheryl Longman)
Physiotherapist
Seating/wheelchair service [OT]
Muscular Dystrophy Scotland worker [link with SW]
Consultant Respiratory Paediatrician
Respiratory Physiologist (Lung Function) 78

79. INTEGRATED CARE MODEL Patient DT Diagnosed DMD aged 4 years
Delay in walking until aged 3 years
Wheelchair-bound since aged 9 years
STOP mutation at exon 69 of DMD gene (10033C>T) 79

80. INTEGRATED CARE MODEL Dean Neurology Genetics School/ Family
Social Work
PhysioRx
Dean
(Not real name)
O.T.
Spinal Sx
Cardiology
Nutrition
Respiratory 80

81. INTEGRATED CARE MODEL Dean School/ Brother with DMD Family
Significant learning difficulties
Attends learning support unit in mainstream school
Dean 81

82. INTEGRATED CARE MODEL Dean Genetics
Registered with Action Duchenne/TREATNMD registry
- Will be notified of any future trials for which eligible
Mum offered 5-yearly echocardiograms (as carrier) 82

83. INTEGRATED CARE MODEL Dean PhysioRx Poor cough
Requires regular chest physioRx
Has cough assist device
Dean 83

84. INTEGRATED CARE MODEL Dean Spinal Sx
Worsening scoliosis over time once wheelchair-bound
Referred spinal service aged 10 years – No scoliosis
By aged 13 had 15O curve
Spinal surgery aged 14 (T3-L5 posterior fusion) 84

85. INTEGRATED CARE MODEL Dean Cardiology
Annual echocardiograms since aged 10 years
No evidence of ventricular dysfunction/cardiomyopathy
Not on any cardiac drugs 85

86. INTEGRATED CARE MODEL Dean Respiratory
Lung function measured 6-monthly at resp. clinic from aged 10
By 2006, FEV1 had fallen to 30% predicted
Having intercurrent respiratory infections and poor cough
Commenced non-invasive ventilation at this stage
Currently on BiPAP 14/6, rate 12
Regular sleep studies to titrate ventilatory requirements 86

87. INTEGRATED CARE MODEL Dean Nutrition Losing weight from 2008 onwards
5kg loss in past year
Unable to feed himself and difficulties in chewing
Having nasogastric feeds
Due for gastrostomy insertion in May 2010
Low BMD on DXA scan – Received Pamidronate pre-spinal Sx 87

88. INTEGRATED CARE MODEL Dean O.T. Seating:
- Has electric wheelchair with manual chair as back-up
Adapted bathroom
Through-floor lift
Tracking hoist system 88

89. INTEGRATED CARE MODEL Dean Social Work Disability Living Allowance
- Mobility and care components both at high level
Respite Care
5 hours per week and 1 weekend in 8
Also accesses Rachel House Hospice for 23 nights per year
Support available for carers i.e. Mum 89

90. INTEGRATED CARE MODEL Dean Neurology
Involvement from time of diagnosis
Assessing time at which wheelchair use most appropriate
Co-ordinating care
Minimising muscle contractures etc.
Tendonotomy and muscle lengthening
Use of splints, etc. 90

91. Dean Genetics Neurology School/ Family PhysioRx Social Work O.T.
Brother with Duchenne MD Dean - learning difficulties
Registered for clinical trials
In from the start Co-ordinators of care
School/
Family
PhysioRx
Social Work
Inadequate cough 2x daily chest physio
Financial support Respite care
Dean
O.T.
Spinal Sx
Powered wheelchair Home adaptations
Spinal fusion 2007
Cardiology
Nutrition
Respiratory
Weight loss - Planned PEG Low BMD
Annual review
On BiPAP since 2006 Annual sleep studies 91

92. ANY QUESTIONS? 92