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1. INVESTIGATION MODALITIES IN
RESPIRATORY DISORDER
(other than TB)
Dr Indramani Prakash
Jr 2
PG Deptt. Of Medicine
Allahabad

2. MODERATOR
Dr. Sujeet Verma(MD)
P.G. Deptt. Of Medicine
MLN Medical college
Allahabad

3. Investigations of Respiratory
System

4. Laboratory methods
 Besides routine laboratory blood and urine
tests, several specific blood and other tests for
respiratory diseases are available..

5. Disease Test
Pulmonary embolism D-dimer
Inherited emphysema α1-antitrypsin
Cystic fibrosis Specific genetic tests
Lung cancer Tumour marker (e.g. CEA)
Malignant mesothelioma Tumour marker (mesothelin, osteopontin,
fibulin)
Pneumonia Procalcitonin
(Latent) tuberculosis infection Tuberculin skin test, interferon-gamma
release assay
Unexplained breathlessness NT-proBNP (increased in heart failure)
Sarcoidosis Angiotensin-converting enzyme (ACE)
Extrinsic allergic alveolitis
(hypersensitivity pneumonitis)
Specific precipitating antibodies
Asthma Total and specific immunoglobulin E, skin
testing with
allergens
Eosinophilic diseases Eosinophils
Connective tissue disorders Immunological tests such as rheumatoid factor
Pleural effusion Total protein, LDH, glucose, cholesterol and
others in
pleural fluid
Table 1 – Specific laboratory tests for some respiratory diseases. NT-proBNP: N-
terminal pro-brain natriuretic

6. Histological and cytological
examination
Histology and cytology play a central role in the diagnosis
of many malignant and benign respiratory diseases,
including infections.
Conventional histopathological techniques are often
supplemented by immunohistochemistry using specific
markers for the differentiation of several neoplasms, such
as small cell neuroendocrine carcinoma and malignant
lymphoma.Cytopathological examination is used mainly in the diagnosis of
malignancies (e.g.malignant effusion). In bronchoalveolar lavage
fluid, it may be helpful in the diagnosis of some interstitial lung
diseases, such as extrinsic allergic alveolitis (hypersensitivity
pneumonitis), eosinophilic pneumonia, alveolar proteinosis or
asbestosis.

7. Respiratory function tests
The main clinical roles of respiratory function tests
include diagnosis, assessment of severity,
monitoring,treatment and evaluation of prognosis.

8. Spirometry
Spirometry is the most important function test – it
measures vital capacity (VC) and forced expiratory volume
in 1 second (FEV1). This permits differentiation between
restrictive and obstructive respiratory diseases. If expired
volume is measured by electrical integration of airflow (using
a pneumotachograph), maximum flow–volume curves can
also
be registered. These tests are used to measure the effect of
bronchodilating drugs on reversibility of obstruction as well
as
to determine responsiveness to bronchial provocation tests.
Simple instruments for patient home use include peak flow

9. a) Patient performing sirometry. b) Interpretation of spirometric
curves.

11. Obstruction
vs.
Restriction

12. Obstructive Lung Disease
 FEV1/FVC < 0.70 defines obstruction
 FEV1 usually decreased
 FVC may be decreased
◦ e.g. if expiration incomplete due to air
trapping
 If FEV 25-75% decreased and all of
the above are normal – “Minimal
airways obstruction”

13. Restrictive Lung Disease
 FVC Decreased
 FEV1 often decreased proportionate
to FVC
 FEV1/FVC Normal or Increased
 Can have simultaneous obstruction
and restriction
 May need lung volume measurements
(RV, FRC, TLC) to confirm.

14. (A) Normal. Inspiratory limb of loop is symmetric and convex. Expiratory limb is
linear. Flow rates at the midpoint of the inspiratory and expiratory capacity are
often measured. Maximal inspiratory flow at 50% of forced vital capacity (MIF
50%FVC) is greater than maximal expiratory flow at 50% FVC (MEF 50%FVC)
because dynamic compression of the airways occurs during exhalation.

15. (B) Obstructive disease (eg, emphysema, asthma). Although all
flow rates are diminished, expiratory prolongation predominates,
and MEF < MIF. Peak expiratory flow is sometimes used to estimate
degree of airway obstruction but is dependent on patient effort.

16. (C) Restrictive disease (eg, interstitial lung disease, kyphoscoliosis). The loop
is narrowed because of diminished lung volumes, but the shape is generally
the same as in normal volume. Flow rates are greater than normal at
comparable lung volumes because the increased elastic recoil of lungs holds
the airways open.

17. Lung capacity and airway
resistance
The total lung capacity can be determined using either gas
dilution techniques or body plethysmography. The latter
method also allows the measurement of airway resistance.
The forced oscillation technique, which measures the
resistance of the total respiratory system, has the advantage
that the patient does not need to perform specific breathing
manoeuvres.

18. Body Plethysmography

20. Pulmonary volumes and
capacities
1) Tidal volume – is the volume of air inspired or expired with
each normal breath = 500ml in young adult man.
2) Inspiratory reserve volume – is the extra volume of air
that can be inspired over and beyond the normal tidal volume
= 3000ml.
3) Expiratory reserve volume – is the extra amount of air
that can be expired by forceful expiration after the end of a
normal tidal expiration ~ 1100ml.
4) Residual volume – is the extra volume of air that still
remain in the lungs after the most forceful expiration ~
1200ml.

21. The pulmonary capacities
Inspiratory capacity – is the volume of air inspired by a maximal inspiratory effort
after normal expiration = 3500ml = inspiratory reserve volume + tidal volume.
The functional residual capacity – is the volume of air remaining in the lungs
after normal expiration = 2300ml = expiratory reserve volume + residual volume.
The vital capacity – is the volume of air expired by a maximal expiratory effort after
maximal inspiration ~ 4600ml = inspiratory reserve volume + tidal volume +
expiratory reserve volume.
Total lung capacity – is the maximum volume of air that can be accommodated in the
lungs ~ 5800ml = vital capacity + residual volume.
Minute respiratory volume – is the volume of air breathed in or out of the lungs each
minute = respiratory rate x tidal volume = 12 X 500ml = 6000ml/min.
All lung volume and capacity are about 20 to 25% less in women than in men and are
greater in athletic persons than in small and asthenic persons.

22. Diffusing capacity
The diffusing capacity of the lung for carbon monoxide (also
known as transfer factor), which is usually performed as
a single-breath test, measures the overall gas-exchange
function of the lung.

23. Single breath Carbon Monoxide
Diffusing Capacity (DlCO)
 Simple/automated
 Standardized normal values available
 10 second breath hold
 Inspire mixture of CO, He and O2
 Measure change in volume of CO
between inspiration and expiration
adjusted for dilution effect with He

24. Blood gas analysis
Arterial blood gas (ABG) measurement to determine the
arterial
oxygen tension (PaO2) and arterial carbon dioxide tension
(PaCO2) is one of the most useful diagnostic tests: blood
can be
sampled directly from an artery, or an estimate can be
obtained
from capillary blood from, for instance, a warmed earlobe.
ABG
measurement allows the diagnosis of hypoxaemia
(decreased
PaO2) with or without hypercapnia (increased PaCO2), a

25. Arterial oxygen saturation (SaO2)
represents the percentage of binding sites on the
haemoglobin molecule occupied by oxygen and offers a
noninvasive method of estimating arterial blood
oxygenation; it is measured directly by an oximeter with
a probe attached to either the finger or the earlobe.
PaCO2 can also be estimated noninvasively, using a
transcutaneous electrode but such devices are not yet
as widely used as oximeters. ABG measurement also
allows evaluation of acid–base disorders.

26. Cardiopulmonary exercise testing
Cardiopulmonary exercise testing (CPET), with determination of
minute ventilation,cardiac and respiratory frequency, oxygen
uptake and carbon dioxide output, is an objective measure of
exercise capacity (spiroergometry). Simpler tests use capillary
oxygen partial pressure measurements during exercise on an
ergometer or symptom-limited
walking tests, such as the 6-min shuttle walk test, with
measurement of SaO2 using an oximeter.

27. Respiratory muscle function
measurement
Respiratory muscle function is commonly assessed by
measuring maximal pressures generated at the mouth
during maximal inspiratory and expiratory efforts against an
occluded airway.

28. Control of ventilation
Tests of ventilatory control include the hyperoxic rebreathing
method and the hypoxia withdrawal method. Simpler, but
less specific, is the measurement of the mouth occlusion
pressure.

29. Diagnosis of sleep breathing
disorders
The diagnosis of sleep-related respiratory disorders
requires special tests. The gold standard is
polysomnography, but simpler tests are available for
screening purposes
(‘respiratory polysomnography).

30. Right heart catheterisation
Right heart catheterisation is used in the differential
diagnosis of pulmonary hypertension.

31. Imaging techniques
Chest radiography

32. - Plain CXR
Xray film provides information on the lung fields , heart
,mediastinum , vascular structures and the thorathic
cage. additional information can be obtained from a
lateral film.

33. Normal Chest X-ray
 Cardiac Structures
◦ Position
 More central in younger infants and children
 More on the L side in older infants and teens
◦ Size
 CARDIO-THORACIC RATIO!
 Cardiac diameter :
 normal individuals < 15.5 cm in males; <14.5 cm in
females.
 A change in diameter of greater than 1.5 cm is
significant.

34. Normal Chest X-ray
 1. Soft tissue structures
◦ Shadows, most commonly, breast
 2. Bony structures
◦ Count the ribs
◦ 8 – 10 ribs should be visible on inspiration
◦ Clavicle placement at 2-3 intercostal
space (if not, may be rotated)

35. Normal Chest X-ray
 3. Diaphragm
◦ Contour
◦ Rounded with sharp pointed costophrenic
and costocardiac angles
◦ Right diaphragm is usually 1-2 cm higher

36. Normal Chest X-ray
 4. Lungs
◦ Start at the top and compare the R and L
◦ Trachea should be midline over the
thoracic vertebrae and air filled
◦ Lung parenchyma becomes lighter as you
we down the lung. If not, it may indicate a
lower lobe or pleural effusion

37. Normal Chest X-ray

38. lateral
Xray

39. PA vs AP views
PA view
 Scapula is seen in
periphery of thorax
 Clavicles project
over lung fields
 Posterior ribs are
distinct
 Position of markers
AP view
 Scapulae are over
lung fields
 Clavicles are
above the apex of
lung fields
 Position of markers
 Anterior ribs are
distinct

40. Penetration
With correct exposure we should barely
see the intervertebral disc through the
heart
 If we see them very
clearly the film is
overpenetrated
 If we do not see them it
is underpenetrated

41. Inspiration vs Expiration

42. It is superior to CXR in determining the position and size of a
pulmonary lesion and whether calcification or cavitations is
present.
It is now routinely used in the assessment of patients with
suspected lung cancer and facilitate guided percutaneous
needle biopsy.
HRCT (high resolution), that uses thin section to provide a
detail assessment of pulmonary parenchymal diseases
( interstitial lung disease , bronchiectasis)
Computed tomography

44. An axial slice of a thin-slice CT acquisition (low-
dose). The yellow arrow indicates a solid pulmonary
nodule.

45. Pulmonary and bronchial
angiography
Pulmonary angiography and bronchial angiography (together
with bronchial artery embolisation for the treatment of
haemoptysis) are invasive techniques for imaging vessels
and
are only used if less invasive techniques (contrast
CT/magnetic
resonance imaging (MRI)) fail or need to be confirmed.

46. Fluoroscopy
Fluoroscopy (an X-ray technique by which respiratory
movement is visualised directly) is used mainly for
guidance of
biopsy of peripheral lung lesions and for differential
diagnosis
of an elevated diaphragm.

47. Magnetic resonance imaging
MRI has the advantage that radiation is avoided. Its main
indications are visualisation of the great vessels and the
heart,
but it is also useful with suspected tumour invasion of the
mediastinum and the chest wall.

48. Chest MRI findings of a middle-aged female patient. A round-like lesion with
long T1 and T2 signals at the upper posterior portion of the right mediastinum ...

49. Ultrasonography
Ultrasonography has become an important imaging
technique. Its advantages are lack of radiation, low cost and
mobility. It is mainly used in the investigation of pleural
effusions (in which it also has a role in guiding thoracentesis)
but also in pleural thickening, chest wall abnormalities, for
the diagnosis of pneumothorax and for biopsies of lesions
adjacent to the chest wall. A special application is
endobronchial ultrasound (EBUS), which can be used for
visualisation of mediastinal lymph nodes as well as
pulmonary parenchymal lesions. Its most important use is
the sampling of
mediastinal lymph nodes in the setting of endoscopic lung
cancer staging, where EBUS has largely replaced

50. Nuclear medicine techniques
Nuclear medicine techniques include perfusion and
ventilation scintigraphy, which are mainly indicated in the
diagnosis of pulmonary embolism but also for regional lung
function studies, e.g. for predicting post-operative lung
function before lung
surgery. Inhalation scintigraphy can be used to investigate
mucociliary clearance.

51. Invasive biopsy techniques
Bronchoscopy
The most important endoscopic method in respiratory medicine is
bronchoscopy; for diagnostic purposes, this is almost exclusively
performed with a flexible bronchoscope using video-assisted
imaging, usually under local anaesthetic. Bronchoscopy is
associated with very few complications. The procedure not only
allows inspection and
sampling of the airways, but also facilitates transbronchial needle
aspiration (TBNA) from the lymph nodes, sampling material from
peripheral lesions with special catheters and brushes, or
transbronchial lung biopsy (TBLB) by forceps, often under
guidance of EBUS
or fluoroscopy. A more elaborate technique to guide the
bronchoscopist to small lesions is electromagnetic navigation.

52. Figure -a) Transbronchial needle aspiration during flexible bronchoscopy. b)
Flexible bronchoscopy showing a tumour
that is almost completely obstructing the right main bronchus, indicating inoperability due
to the location of the tumour.

53. Bronchoalveolar lavage
Bronchoalveolar lavage (BAL) involves the instillation of
saline via a bronchoscope in order to collect specimens for
cytological or microbiological investigation. It is used mainly
in
interstitial lung diseases or lower respiratory tract infections,
as material can easily be obtained from the periphery of
the lung.

54. Autofluorescence and narrow-
band imaging
Autofluorescence or narrowband imaging may be helpful
in the detection of precancerous lesions and early cancers
located in the bronchial tree.

55. Percutaneous needle biopsy
Percutaneous (or transthoracic) needle biopsy is mainly
performed to investigate peripheral lung lesions when
bronchoscopy is negative. It is performed with the guidance
of
either fluoroscopy or, preferably, CT. When lesions are
adjacent
to the chest wall, ultrasound guidance can also be used.

56. Thoracentesis and pleuroscopy
(medical thoracoscopy)
Thoracentesis (pleural fluid aspiration or ‘tap’) is a frequently
performed procedure in pleural effusions, preferably used
under ultrasound guidance, at least when the effusion is
small. Additional biopsy procedures, such as closed-needle
biopsy of the pleura or pleuroscopy (medical thoracoscopy),
may be necessary to confirm or exclude malignant or
tuberculous causes of an effusion.

57. Surgical methods
Surgical investigative methods include mediastinoscopy and
the minimally invasive technique of video-assisted thoracic
surgery (VATS). Mediastinoscopy is used for biopsy of
mediastinal lymph nodes. VATS has almost completely
replaced the use of open surgery for diagnostic purposes in
intrathoracic lesions (including interstitial lung disease), in
which the aetiology remains uncertain after performance of
the above less invasive procedures.

59. NEXT SEMINAR BY Dr. NIKESH
CALCIUM METABOLISM AND MEDICAL BONE
DISEASE
MOD-PROF. SARITA BAJAJ(DM ENDO)

60. THANK YOU