1. Restrictive lung disease
Dr Duncan Powrie
Consultant Chest Physician
Southend University Hospital
December 2018

2. NOTES ARE FOR INTERNAL USE ONLY - DO NOT SHOW TO CUSTOMERS
Simple spirometry
FEV1 = Forced Expiratory Volume in 1 second (how much you can blow out in the first second of a forced blow)
FVC = Forced Vital Capacity (how much you can breathe out altogether in a forced blow)
VC = Vital Capacity (how much you can sigh out altogether in a full, steady blow)
FEV1/FVC ratio = a calculation using the above measurements (% of total that can be forced out in the first second )
NOTES ARE FOR INTERNAL USE ONLY - DO NOT SHOW TO CUSTOMERS

3. Performing spirometry1
Record the patient’s sex age and height to find their predicted normal values
Ask the patient to:
breathe in as deeply as possible
blow out forcibly as hard and fast as possible until there is nothing left to expel*
Repeat the procedure twice
This should give 3 readings, with at least 2 within 100ml or 5% of each other
NOTES ARE FOR INTERNAL USE ONLY - DO NOT SHOW TO CUSTOMERS
If performing VC, patients should breathe out at a comfortable pace, and continue until expiration is complete
Reference
1. BTS Spirometry in Practice. A practical guide to using spirometry in primary care. Direct Publishing Solutions (September 2000).
* severe patients may take up to 15 seconds
Consistent result Inconsistent result

5. Obstructive vs.restrictive patterns
If the ratio FEV1/FVC <70%, obstruction is present
If this ratio is normal but FEV1 and FVC are both reduced, restrictive pattern is present
A restrictive pattern should be referred to the doctor to check for lung fibrosis, pleural disease, chest wall disease.
Obstructive disorder Restrictive disorder
e.g COPD e.g. Fibrosing alveolitis,
pleural disease
FEV1 reduced (<80%) reduced (<80%)
FVC normal or reduced reduced (<80%)
FEV1/FVC ratio reduced (<70%) normal (>70%)
NOTES ARE FOR INTERNAL USE ONLY - DO NOT SHOW TO CUSTOMERS
A healthy person can breathe out 70 % or more of their FVC in the first second. Anything which obstructs flow will slow the rate of exhalation and thus reduce the FEV1 but with much less effect (if any) on the FVC. Thus the ratio of FEV1 to FVC (expressed as a percentage by the formula: FEV1/FVCx100) defines whether or not obstruction is present. If the ratio is less than 70% then the abnormality of airflow is obstructive.
If the FEV1/FVC ratio is normal, but both FEV1 and FVC are reduced, a restrictive deficit is present which would indicate further investigation by a respiratory physician to look for other conditions such as lung fibrosis, pleural disease or chest wall disease.

6. Assessment of a patient with restrictive spirometry
Pulm fibrosis (severe), neuromuscular disease, obesity , chest wall disease
History
Examination
CXR
Full PFTs (inc tests of resp muscle function)
Oximetry
Blood gases
Sleep study

7. Pulmonary fibrosis Progressive exertional breathlessness Dry cough
Arthralgia 20%
Weight loss
Finger clubbing in 50%
End inspiratory ‘velcro’ crackles
Cyanosis
Cor pulmonale

11. Epidemiology 6-28/ 100 000yr M:F 1.7:1 Median age of diagnosis 70
Uncommon before 50

12. Risk factors Exposure to metal or wood dust Organic solvents
Mycotoxins
EBV, Hepatitis C
Cigarette smoking
Family history

15. Management No really effective evidence based treatment
Information provision and supportive management is key
Monitor lung function if minimal symptoms
If deteriorating lung function consider triple therapy

16. Pirfenidone Anti- inflammatory and anti-fibrotic action
Inhibits fibroblast proliferation
GI side effects
May reduce decline in lung function
Consider if FVC between 80 and 50% predicted

17. Breathlessness Hypoxia is common as is desaturation on exercise
LTOT if pO2 < 7.3 kPa or <8 if signs of pulmonary hypertension
Ambulatory oxygen if desaturates on exertion

18. Cough Treat reflux Consider simple linctus Oral codeine
Consider oramorph or MST in end stage disease

19. Pulmonary rehabilitation
No randomised controlled studies
But strong evidence base in COPD
Improves QoL, reduces breathlessness
Deconditioning, breathlessness, nutritional deficit, fatigue and social isolation
Oxygen may be required to allow exercise

20. Other measures Opioids Anxiolytics
Relaxation and distraction techniques
Breathlessness clinic

21. Causes of acute deterioration
Reflux
Infection
Pneumothorax
pulmonary embolism

22. Lung transplantation Patients <65 TLCO <40%
70-80% 1 year survival and 50% 5 yr survival

23. Prognosis Variable Median survival 2.5-3.5 years
Improved survival associated with young age, female sex, less honeycombing and better lung function at diagnosis
Death from respiratory failure or infection
Lung cancer common

24. Ventilatory pump failure
Myopathies- myotonic dystrophy
- muscular dystrophy
Neuropathy- MND
- bilateral diaphragm paralysis
- Guillain- Barré
NMJ abnormalities- myasthenia gravis
-anticholinesterase poisoning
Chest wall – obesity (often assoc obstructive sleep apnoea)
- scoliosis
- post thoracoplasty

25. Respiratory consequences of obesity
Obstructive sleep apnoea
Obesity hypoventilation syndrome
Acute hypercapnic respiratory failure
Postsurgical complications
Pulmonary hypertension

26. Mrs MC 54♀ Asthma 38 years Never smoked Alcohol ½ bottle whisky day
No ITU admissions
Salbutamol prn only
Never smoked
Alcohol ½ bottle whisky day
Obese 127kg

27. Admission Presented with 4/7 SOB and wheeze No cough
Given chlordiazepoxide, beclomethasone and atrovent inhalers by GP
No better so called ambulance

28. Examination PEFR 150 (450) L/min RR 22 Sats 95% on 2 L/min
P 130 regular
Diminished breath sounds throughout
No wheeze

29. ABG pH
pCO2 9.57 pO
HCO
BE -1.3

30. Admission bloods Trop T 0.198 K+ 5.2 Urea 20.9 Creat 336 Hb 15.0
WCC 14.3
Neut 11.9
Plt 255
ALT 1230
Bilirubin 39
GGT 246
Alb 38
ALP 130
C. Ca
INR 1.7

32. Immediate treatment Nebulised salbutamol and atrovent Steroids
Pabrinex and vitamin B
Regular chlordiazepoxide stopped
BiPAP commenced

33. Respiratory review Recent increase in alcohol consumption
Recent rapid weight gain
Daytime somnolence, falling asleep at work
Epworth score 14/24
Continue nocturnal BiPAP
Sleep study as inpatient

34. Sleep study Low sats throughout- down to 70% Multiple hypopnoeas
Some apnoeas
Lots of paradox
AHI- 29
Compatible with OSAHS

35. Discharge ABG pH
pCO2 5.61
pO2 8.30
HCO
BE 1.5

36. Follow up Weight loss 106.5kg No alcohol since discharge
No daytime sleepiness
Epworth score 0/24
ABG continue to improve
BiPAP stopped

37. Obesity hypoventilation syndrome Definition
Severe obesity BMI > 30 kg/m2 and diurnal PaCO2 > 45 mmHg (6 kPa)
In the absence of other known cause of hypoventilation
Obesity hypoventilation syndrome is defined by the combination of obesity and awake chronic hypercapnia in the absence of known cause of hypoventilation. Clinically these patients symptoms such as dyspnea, morning headhakes, exessive daytime sleepiness..
Olson et al Am J Med 2005 37 37

38. Obesity hypoventilation syndrome Clinical presentation
Pèrez de Llano Chest 2005
Morbid obesity OSA dyspnoea daytime hypersomnolence

39. Hospitalised patients
PREVALENCE
Increases with BMI; Prevalence >25% for BMI>40 kg/m2 and >50% for BMI>50 kg/m2
Hospitalised patients
Stable state OSA
15% in the general population of ambulatory obese patients?
Mokhlesi B, CHEST 2007
Nowbar, Am J Med 2004

40. Mechanisms underlying hypercapnia in obesity
Mokhlesi et al. Proc Am Thorac Soc 2008
Neurohormonal abnormalities 1 2 3 4

41. Obesity hypoventilation syndrome
High prevalence of associated cardiovascular morbidity in observational cohorts
Compared with obese control subjects, patients with OHS were statistically much more likely to have been diagnosed with:
Congestive heart failure (OR 9; 95% CI, 2.3–35)
Angina pectoris (OR, 9; 95% CI, 1.4–57.1)
Cor pulmonale (OR, 9; 95% CI, 1.4–57.1)
Berg Chest Mokhlesi Proceedings ATS 2008

42. Treatment
Weight loss
CPAP
BiPAP

43. Obesity hypoventilation syndrome
Take home message
Highly prevalent and easy to diagnose but underdiagnosed
Non invasive ventilation (NIV) improves blood gases, sleep, daytime sleepiness and mortality
Impact of NIV on cardiovascular morbidity?
Assessment and treatment of cardiovascular and metabolic risk recommended in OHS patients in association with NIV

44. Mr CB 75 male Raised PSA – normal bone scan, CT CAP unremarkable
General deterioration
Wgt loss, lethargy,
poor appetite
2 weeks dyspnoea – unable to sleep

45. No wheeze, no crackles
Sats 84% on air
Nil to find on examination
CXR small volume lungs

46. pH 7.24
pCO pO
HCO3 42.5
BE 9.8

47. Confused
Minimal history available
Dysarthric
Generally wasted
Poor respiratory effort
Thoraco-abdominal paradox
Multiple fasciculations

48. MND and respiratory failure
Respiratory failure in MND is common and a frequent cause of death
It may be the cause of presentation
Deterioration may be rapid
Multidisciplinary involvement is key
There is some evidence that NIV improves survival and quality of life

50. Mrs JT 45 female Kyphoscoliosis from birth Spinal fusion aged 14
Married
2 teenage chidren
Nil else in PMH

51. 4-6 week history of dyspnoea on exertion
1 week history of ankle oedema and new onset confusion
Started on salbutamol and frusemide by GP

52. Wheezy
JVP raised, oedema to knees
WCC 12 CRP 50
Na 115
pH pCO pO HCO3 54.1

53. Commenced on BiPAP
Deteriorating conscious level and worsening acidosis
Intubated
Echo- pulm hypertension, PAP 65mm Hg
Weaned to BiPAP

54. 4/52 post discharge Using BiPAP all night 15:5
Exercise tolerance improved to half a mile
Oedema resolved
No daytime somnolence
pH 7.42 pCO pO HCO3 38.4
Commenced on LTOT
IPAP increased 18

55. 2 years Unlimited ET BiPAP 24:5 pH 7.45 pCO2 5.33 pO2 9.77 HCO3 27.2
Echo PAP 35mm Hg

56. Differential diagnosis of restrictive spirometry
How to assess for respiratory muscle weakness
The importance of OHS