Transcript Restrictive lung diseases

By
Eman I. Desoki
MsC, Intensive Care Medicine.
ICU Fellow Assistant in NHTMRI.
Objectives
 To understand the definition of restrictive lung
diseases & its pathophysiology.
 To know how they present to the critical care
settings.
 To know how to approach with these group of
patients.
I- Classification of Respiratory
Diseases
1- Inflammtory
2- Obstructive
3- Pulmonary vascular diseases
4- Infectious
5- Neoplastic
6- Restrictive
II- Definition of Restrictive Lung
Diseases:
These are diseases that are characterized
by reduced lung volume, either because of
an alteration in lung parenchyma or
because of a disease of the pleura, chest
wall , or neuromuscular apparatus.
II- Definition of Restrictive Lung
Diseases:
In physiological terms, restrictive lung diseases are
characterized by :
- Reduced total lung capacity
( TLC)
- Reduced vital capacity
or reduced resting lung volume.
(
VC)
Accompanying characteristics are :
- Preserved airflow and
- Normal airway resistance, which are measured as the
functional residual capacity
(
FRC).
III-Causes of Restrictive Lung
Diseases:
A- Intrinsic lung diseases; diseases of the lung parenchyma:
-Organic dust exposure e.g. farmer's lung, bagassosis, and mushroom
worker
lung,
which
all
cause
hypersensitivity
pneumonitis.
-Inorganic dust exposure e.g. silicosis, asbestosis, talc,
pneumoconiosis, berylliosis, hard metal fibrosis, coal worker‘s
pneumoconiosis.
-Collagen vascular disease e.g. including scleroderma, polymyositis,
dermatomyositis, systemic lupus erytheromatosis,
rheumatoid arthritis, and ankylosing spondylitis.
-Idiopathic e.g. acute interstitial pneumonia, idiopathic pulmonary
fibrosis.
III-Causes of Restrictive Lung
Diseases:
B- Extrinsic disorders; or extraparenchymal
diseases:
- Chest wall disease: severe kyphosis & scoliosis
- Pleural diseases: massive effusion & tension
pneumothorax
- Neuromuscular diseases: Myasthenia Gravis &
Guillain Barre $
IV- Pathophysiology:
In cases of intrinsic lung disease, the excessive
elastic recoil of the lungs, in comparison to the
outward recoil forces of the chest wall will lead
to reduce all lung volumes.
Arterial hypoxemia in these disorders is
primarily caused by ventilation-perfusion
( V\Q mismatching).
IV- Pathophysiology:
In cases of extrinsic disorders of the pleura and
thoracic cage, the total compliance of the
respiratory system is reduced and hence, lung
volumes are reduced.
As a result atelectasis will occur and so gas
distribution becomes nonuniform, resulting in
(V\Q)mismatch and hypoxemia.
-
V- Diagnosis:
A-History:
- Occupational
-Drug history
-Family history
history
B-Clinical Presentation:
Symptoms
exertional dyspnea
cough
hemoptysis
Chest pain
physical findings (Signs):
High-pitched
rhonchi
Cyanosis
(advanced)
Recurrent RTI
Digital clubbing
(IPF)
They present to ICU with Respiratory Failure &
arterial hypoxemia .
C-Laboratory Studies:
 Anemia: vasculitis.
 Polycythemia: hypoxemia in advanced disease.
 Leukocytosis: acute hypersensitivity pneumonitis.
 Screen for collagen vascular disorders:
- Antinuclear antibodies (ANA) and rheumatoid factor
(RF).
- Creatine kinase for polymyositis. (
CK )
- Antineutrophilic cytoplasmic antibodies (c-ANCA) for
vasculitis.
- Antiglomerular basement membrane antibody for
Goodpasture’s syndrome.
D- Imaging Studies:
Intrinsic lung disorders:
Chest radiography;
Extensive bilateral reticulonodular opacities are seen in both
lower lobes.
High-resolution CT scanning of the chest
The finding of honeycombing correlates with advanced
fibrosis and indicates a poor prognosis.
E-Other Tests:
DLCO
Flouroscopy
BAL
Biopsy
PFTs
Pulmonary function tests:
 The diagnosis of restriction is based on a decreased TLC.
(
TLC)
 The assessment of the severity of restriction is also based on
TLC.
 preserved or increased FEV1 ∕ FVC ratio suggests a restrictive
pattern.
(
or
FEV1 ∕ FVC)
A patient with
emphysema has
much higher lung
compliance
compared to a
patient with intrinsic
lung disease.
-In nonmuscular diseases of the chest wall e.g.
severe kyphoscoliosis produces a restrictive
pattern,
 The TLC is markedly reduced.
( TLC )
 vital
capacity is reduced with relative
preservation of the RV (residual volume)
thus, RV-to-TLC ratio is elevated. ( RV ∕TLC )
 Maximal inspiratory and expiratory pressures
are decreased.
(
MIP & MEP )
The diffusing capacity of lung for carbon monoxide
(DLCO) :
 DLCO is the most sensitive parameter, and
findings may be abnormal even when the lung
volumes are preserved.
 A normal DLCO value excludes intrinsic lung
disease and indicates a chest wall, pleural, or
neuromuscular cause of restrictive lung disease.
sis
Bronchoalveolar lavage :
 Performing BAL lymphocytosis in patients with IPF
may help predict steroid responsiveness.
 A predominance of T-lymphocytes with an elevated
CD4-to-CD8 ratio is characteristic but not diagnostic
of sarcoidosis.
 BAL fluid may contain malignant cells, asbestos
bodies, eosinophils, and hemosiderin
macrophages, which assist in making a diagnosis.
-Lung
biopsy:
may help lead to a specific diagnosis,
assess for disease activity, exclude neoplastic
and infectious processes and predict the
outcome.
Open lung biopsy can be as valuable in
selected patients as high-resolution CT
scanning.
Diagnosis
1- Anemia
2-Polycythemia
3- Leukocytosis
4- Creatine Kinase
5- ANA, c-ANCA
6- Fluoroscopy
Intrinsic
Causes
Extrinsic Causes
++++
++
++
_
++++
_
++
++
++
+++
_
+++
Diagnosis
7- TLC
- FEV1 ∕ FVC
- RV ∕ TLC
8- DLCO (Normal)
9- High resolution
CT
10- BAL
11- Lung biopsy
Intrinsic Causes
Extrinsic Causes
+++
+++
+
_
++++
++++
++++
+++
++=
+++
++++
+ (Infection)
_
_
VI- Treatment
A- Supportive therapy:
 Precipitating factors or complications.
 Supplemental oxygen therapy.
 In advanced disease, Mechanical
ventilation;
 Invasive mechanical ventilation.
 noninvasive ventilation.
 Non Invasive ventilation is
beneficial:
-It helps relieve dyspnea and pulmonary
hypertension.
-improve
RV
and
gas
exchange.
-Also, hospitalization rates are markedly
reduced and activities of daily living are
enhanced.
 Guidelines for ventilator settings in
restricive lung disease:
-Intrinsic lung disease:

Choose a mode capable of supporting oxygenation
& ventilation, such as PC or VC-CMV. No evidence
to date that PV is superior to VV.

Maintain SaO2 ≥ 88% to 90%.

Apply a PEEP level that prevents alveolar collapse
and overdistention to prevent lung damage. PEEP
may allow reduction of FiO2 to safe level.

Keep P plateau ‹ 30 cmH2O by lowering
Vt to 4 to 6 ml\ Kg.

Allow
permissive
necessary.

If VV is selected, the descending flow
waveform is of choice.
hypercapnia
if
Extrinsic disorders: e.g. neuromuscular
disease







Full or partial support.
Negative or positive pressure ventilation.
Non invasive or invasive ventilation.
VV, high Vt 12-15 ml\Kg, f= 8-12 breaths\min.
Inspiratory flow rates ≥ 60L\ min to meet
patient need (Ti about 1 sec. to start)
Flow waveform: constant or descending ramp.
PEEP= 5 cmH2O may be needed to releive
dyspnea.
B- Definitive (Medical):
 Treatment depends on the specific diagnosis,
which is based on findings from the clinical
evaluation, imaging studies, and lung biopsy.

Corticosteroids,
immunosuppressive agents
(Azathioprine, cyclosporin, cyclophosphamide &
methotrexate) are the mainstay of therapy for
many of the interstitial lung diseases.
 Treatment of neuromuscular
diseases includes:
- preventive therapies according to VC
& MIP.
- Plasmaphresis..
- IVIG.
- Corticosteroids (early ?)
- Immunosuppressive agents.
 Management for obesity (BMI≥40) .
Lung Transplantation:
 The prognosis for patients with IPF who do
not respond to medical therapy is poor;
usually die within 2 - 3 years.
 These and other patients with severe
functional impairment, oxygen dependency,
and a deteriorating course should be listed for
lung transplantation.
Key Messages
 The natural history of interstitial lung diseases is
variable. It depends on the specific diagnosis, the
extent and severity of lung involvement based on
high-resolution CT scanning and lung biopsy.
 IPF is typically progressive disorder, and patients
have a mean survival of 3-6 years after diagnosis.
 Early recognition of IPF is important for directing
patient management and predicting prognosis.
 Patients with IPF who do not respond to
medical therapy; usually die within 2-3 years.
 Patients with severe functional impairment,
oxygen dependency, and a deteriorating course
should be listed for lung transplantation.
 Pulmonary sarcoidosis has a relatively benign
self-limiting course, with spontaneous recovery
or stabilization in most cases. Approximately
15% of patients develop pulmonary fibrosis and
disability.
 Prognosis
for
collagen-vascular
diseases,
eosinophilic pneumonia and drug-induced lung
disease is generally favorable with treatment.
 Patients
with chest wall diseases and
neuromuscular disorders develop progressive
respiratory failure and an intercurrent pulmonary
infection.
 Mechanical ventilation settings are not the same
for all patients suffering restrictive lung diseases ,
however it is tailored according to patient response
for both medical & supportive therapies.