Download Oxygen and NIV in COPD

Oxygen and NIV in COPD
Dr Simon Lloyd-Owen
Respiratory Consultant
London Chest Hospital
Barts Health NHS Trust
Oxygen and NIV
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Mechanism of hypoxia and hypercapnia in
COPD
Oxygen and NIV use during acute
exacerbations
Complications of chronic hypoxia
Right heart failure
Long term oxygen therapy
Ambulatory and short burst oxygen
Use of NIV long term
Lung function
(FEV1)
Natural history of COPD
Severe
Very
Severe
Mild
Moderate
Time (years)
Natural history of COPD
Lung function
(FEV1)
Severe
Mild
Moderate
Time (years)
Natural history of COPD
Oxygen levels
Lung function
(FEV1)
Severe
Mild
Moderate
Time (years)
Natural history of COPD
Mild
Moderate
Time (years)
CO2 levels
Oxygen levels
Lung function
(FEV1)
Severe
Ventilation
Intercostal
muscles and
diaphragm
contract
Pressure
inside chest
less than
outside
Air is sucked
into lungs
INSPIRATION
EXPIRATION
Air is
pushed
out of
lungs
Pressure
inside
chest
greater
than
outside
Elastic
recoil of
lungs
forces
them to
contract
Intercostal
muscles
and
diaphragm
relax
Normal control of ventilation
Stimulation of breathing
centre in brain
Stimulation of breathing
centre in brain
Controls
depth of
Blood has low
oxygen levels
e.g. during
exercise
speed and
ventilation
Blood has
high carbon
dioxide levels
e.g. when
sitting quietly
Gas exchange (diffusion)
CO2 diffuses
quicker than O2
Mechanisms of hypoxia in COPD
Hypoventilation
Diffusion abnormality
Natural history of COPD
Mild
Moderate
Time (years)
CO2 levels
Oxygen levels
Lung function
(FEV1)
Severe
Exacerbations
Hypoventilation
Treatment during exacerbations
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Antibiotics
Bronchodilators
Oral steroids
Mucolytics
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Oxygen….
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Normal control of ventilation
Stimulation of breathing
centre in brain
Stimulation of breathing
centre in brain
Controls
depth of
Blood has low
oxygen levels
e.g. during
exercise
speed and
ventilation
Blood has
high carbon
dioxide levels
e.g. when
sitting quietly
Hypoventilation in COPD
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Obstruction to airways
Hyper-expanded lungs
Hypoxia stimulates
increase ventilation
Unable to
increase
ventilation
Hypoxic and
hypercapnic
Type II
Respiratory
Failure
Too
much
oxygen
Control of ventilation with
hypercapnia
Stimulation of breathing
centre in brain
X
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Blood has low
oxygen oxygen
normal
levels
levels
Too much oxygen
given
Brain no longer
responds
X
Controls
depth of
speed and
ventilation
X
Blood has
high carbon
dioxide levels
Worsening hypoventilation and
hypercapnia
Treating COPD Acutely
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Use controlled oxygen therapy:
• 0.5 to 2 l/min via nasal cannulae
• 24% to 28% masks using venturi valves
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Aim to keep oxygen saturations 88 to
92%
Do blood gases regularly to monitor CO2
levels
Consider non invasive ventilation if high CO2 and
low pH (acidosis)
NIV devices
Non invasive ventilation
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Also improves hypoventilation
Delivers high pressure during inspiration
(IPAP) to improve ventilation
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Improves oxygenation
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Also prevents or reduces hypercapnia
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Useful in all conditions causing
hypoventilation and Type II Respiratory
Failure
Acute NIV in COPD
Definite evidence of a benefit on:
 Intubation rate (27% to 15%)
 In-hospital mortality (20% to 10%)
 Complications (mostly ventilator
associated pneumonia)
 Length of hospital stay
Possibly:
 Survival advantage at 3 months and 1
year when compared to historical
intubated controls
Number needed to treat
Outcome
Number
of
studies
Number
of
patients
Number
Relative
needed to
risk
treat
Treatment
failure
7
529
0.51
5
Mortality
7
523
0.41
8
Intubation
8
546
0.42
5
Complications
2
143
0.32
3
Oxygen alert card
Natural history of COPD
Mild
Moderate
Time (years)
CO2 levels
Oxygen levels
Lung function
(FEV1)
Severe
Chronic hypoxia
Possible consequences:
 Pulmonary hypertension
 Right heart failure (oedema)
 Polycythaemia (increased red blood
cells) – increase risk of stroke
 Increase in symptoms in ischaemic
heart disease
 Fatigue, cognitive impairment, poor
sleep, depression
Right heart failure - mechanism
Vasoconstriction
Blood is diverted to areas
of the lungs with more
oxygen in them
Right heart failure - mechanism
Vasoconstriction
COPD – all areas of the
lungs have low oxygen
levels
All blood vessels constrict
in response to low oxygen
levels
Right heart failure - mechanism
R
High pressure in pulmonary
arteries – pulmonary
hypertension
R
Right side of the heart
hypertrophies, dilates and
then fails
Cor Pulmonale
Raised JVP
Enlarged
liver
Ascites
Peripheral
oedema
Nocturnal hypoxia
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Some patients with COPD are only hypoxic
overnight
Some may also have co-existent sleep
apnoea or hypoventilation due to obesity
Long standing nocturnal hypoxia can also
lead to right heart failure
Overnight oximetry useful if signs of right
heart failure with normal daytime oxygen
saturations, obesity or suspicion of sleep
apnoea
Oximetry
Patients with
saturations of less
than 90% for more
than 10% of the
night are at risk of
developing right heart
failure
Oxygen therapy
1980s 2 trials showed benefit of long term
oxygen therapy (LTOT) on hypoxic COPD
patients*
 Improved survival (5 year from 25% to
41%)
 Less polycythaemia
 Prevention of progression of pulmonary
hypertension
 Improvement in neuropsychological health
*Ann Intern Med 1980 93: 391.
*MRC trial Lancet 1981 93: 391
Cumulative percent survival (%)
LTOT Survival curves
100
90
80
NOTT 24hr
70
60
50
NOTT 12hr
MRC O2
40
30
MRC controls
20
10
0
10
20
30
40
50
Time (months)
60
70
LTOT - when to refer
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Very severe airflow obstruction (FEV1
< 30% predicted)
Cyanosis
Polycythaemia
Peripheral oedema
Raised jugular venous pressure
Oxygen saturations ≤ 92% breathing air
when stable (not during exacerbation)
Consider in patients with severe airflow
obstruction (FEV1 30–49% predicted).
LTOT – when to prescribe
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Two blood gas measurements when stable
and on optimal therapy at least 3 weeks
apart
PO2 less 7.3 kPa or
PO2 7.3 to 8.0 kPa and evidence of
polycythaemia, peripheral oedema or
nocturnal hypoxia (guidelines say less
than 90% for 30% of the night)
Should have stopped smoking
LTOT – what to prescribe
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Blood gas measured on different flow rates of
oxygen to ensure PO2 > 8.0 kPa without large
rise in PCO2
At least 15 hours a day
Oxygen concentrator (1-4 l/min) via nasal
cannulae (with back up cylinder)
6 monthly follow up and reassessment including
measure of pulse oximetry
Yearly measurement of blood gases?
Consider symptoms of hypercapnia – early
morning headaches, daytime tiredness
Cor Pulmonale – other treatments
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Loop diuretics e.g. Furosemide,
Bumetanide
Metolazone (watch renal function)
No evidence for use of ACE inhibitors,
Calcium antagonists (worsen oedema),
Digoxin
Fluid restriction
Low salt diet
Intravenous diuretics may be needed
periodically
Ambulatory oxygen
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Should be provided for non-housebound
patients on LTOT
For others, it can improve exercise tolerance
and breathlessness
Small portable cylinders
Conserving devices
Portable concentrators now available
Need to demonstrate fall in oxygen
saturation on exercise with improvement in
breathlessness or exercise tolerance with
oxygen
Borg breathlessness scale
Please circle the number that best describes your
shortness of breath, on average, over the last 24 hours
0
Nothing at all
0.5
Very, very slight (just noticeable)
1
Very slight
2
Slight
3
Moderate
4
Somewhat severe
5
Severe
6
7
Very severe
8
9
Very, very severe
10
Maximal
Visual Analogue Score
Worst imaginable
breathlessness
No breathlessness
Some centres also use the 6 minute walk
test – how far can patient walk in 6
minutes with and without oxygen?
Short burst oxygen therapy
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Short-burst oxygen therapy should only
be considered for episodes of severe
breathlessness in patients with COPD not
relieved by other treatments.
Short-burst oxygen therapy should only
continue to be prescribed if an
improvement in breathlessness following
therapy has been documented.
Natural history of COPD
Mild
Moderate
Time (years)
CO2 levels
Oxygen levels
Lung function
(FEV1)
Severe
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Compared to other conditions – Brompton
1990s
Post polio
Tuberculosis
Neuromuscular
Kyphoscoliosis
% continuing NIPPV
100
80
60
COPD
40
20
Bronchiectasis
0
0
1
2
3
Years
N=180
4
Simonds et al. Thorax 1995
5
Compared to other conditions – LCH 1990 - 2005
Percentage continuing NIV
100
90
Kyphoscoliosis
80
Obesity H S
70
60
Neuromuscular
50
Thoracoplasty
40
COPD
30
20
Bronchiectasis
10
0
5 years
4.5 years
4 years
3.5 years
3 years
2.5 years
2 years
1.5 years
1 year
0.5 years
N=412
Compared to LTOT - observational
Simonds AK & Elliot MW Thorax 1995;50:604-609
Compared to LTOT – Randomised Control Trial
McEvoy RD, et al. Thorax 2009;64:561-66
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Percentage change
Admissions
40
20
27
0
-20
LTOT
NIV
-20
-40
-45
-60
-75
-80
Hospital admissions
ITU admissions
Clini et al Eur Resp J 2002
P>0.05
More evidence of reduced admissions
60
*p<0.0001
50
**p<0.003
40
30
COPD
20
Bronchiectasis
p<0.002
TB*
10
0
Baseline
Yr
1
Leger et al : CHEST 1994
Yr
2
Kyphoscoliosis*
Duchenne**
n=183
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
London Chest study
14 patients with severe
COPD (mean FEV 30%
pred) and Type II
respiratory failure
Randomisation
3 months of oxygen
therapy alone
3 months of oxygen
and nocturnal NIV
Crossover
3 months of oxygen
and nocturnal NIV
3 months of oxygen
therapy alone
Meecham Jones, et al : A J Respir Crit Care Med 1995
Oxygen levels during the day
PaO2 (mmHg)
75
60
45
45.2 (5.5)
30 Mean (SD)
0
Run-in
43.9 (6.9)
O2 Alone
50.1 (6.9)
O2+ NIV
Meecham Jones, et al : A J Respir Crit Care Med 1995
CO2 levels during the day
PaCO2 (mmHg)
75
60
45
55.8 (3.4)
Mean (SD)
57.1 (5.5)
Run-in
O2 Alone
52.5 (4.5)
30
0
O2 + NIV
Meecham Jones, et al : A J Respir Crit Care Med 1995
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Lung function (FEV1)
Improvement of 140 ml after 2 months
Windisch W, et at. Chest 2005;128: 657-62
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
MRC Dyspnoea Scale
1.
2.
3.
4.
5.
Breathless on strenuous exercise only
Breathless when hurrying or walking up
slight hill
Walk slower than other people on level
due to breathless or have to stop for
breath when walking at own pace
Stops for breath after walking about
100m or after a few minutes on level
Too breathless to leave house or
breathless on dressing or undressing
MRC Dyspnoea Scale
Dyspnoea score
4
NIV
LTOT
3
2
M0
M12
Time in months
M24
Clini E, et al. ERJ 2002;20:529-538
Exercise tolerance (6 minute walk test)
End of NIV
Diaz O, ERJ 2005;26:1016-23
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Quality of life – St George’s
p=0.007
p=0.52
p=0.03
SGRQ Score
100
80
Mean
60
40
20
0
Run-in
O2 Alone
O2 + NIV
Meecham Jones, et al : A J Respir Crit Care Med 1995
More evidence of improved Q of L
＊
SGRQ score %
70
＊
60
50
40
30
20
10
0
Activity
Before NIPPV
Impact
Symptoms
Total
After 6 months of NIPPV
Perrin et al : Eur Respir J 1997
Quality of Life – MRF 28
P=0.041
MRF-28: Maugeri Foundation Respiratory Failure Questionnaire
Clini E, et al. ERJ 2002;20:529-538
Long term NIV – possible benefits?
Survival
Hospital Admissions
Blood Gases
Lung Function
Exercise Tolerance
Quality of Life and Symptoms
Sleep Quality
Total Sleep Time
p=0.0001
400
p=0.001
p=0.03
321
Min.
300
267
200
225
(129277)
(215335)
(236400)
100
0
Run-in
O2 Alone
O2 + NIV
Meecham Jones, et al : A J Respir Crit Care Med 1995
Long term NIV – possible benefits?
Survival
?
Hospital Admission
Blood Gases
Lung Function
√
√
?
Exercise Tolerance
√
Quality of Life and Symptoms √
Sleep Quality
√
When to start long term NIV
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Significant, symptomatic hypercapnia,
on LTOT and maximal medical therapy
Other symptoms: dyspnoea, poor QoL
Frequent exacerbations, admissions,
ITU stays
2 or more exacerbations requiring NIV
acutely
Well motivated
Tolerance of NIV previously
Summary
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Causes of hypoxia and hypercapnia
in COPD
Controlled oxygen therapy in
exacerbations (+/- acute NIV)
Complications of chronic hypoxia
LTOT indications and prescription
Ambulatory and short burst
Use of home NIV for chronic hypoxia
and hypercapnia
Thank you
Any questions?