INTRODUCTION & INVESTIGATIONS TO RESPIRATORY DISEASES

Dr. Firoz A Hakkim. MBBS , MD Dept. Of Pulmonary Medicine K S Hegde Medical Academy

Human respiratory system--That organ of body which participate in

respiration known as respiratory organ and that system which participate known as respiratory system.

The human respiratory system can be divided into two group stracturally.As --

* The upper respiratory tract– Nose, nasal cavity,sinuses,pharynx.

* The lower respiratory tract-- Larynx, trachea, bronchial tree,lungs.

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And the organs of the respiratory tract can be divided into two groups functionally.

* The conducting portion-- system of interconnecting cavities and tubes that conduct air into the lungs. nose, pharynx, trachea, bronchi.

* The respiratory portion— system where the exchange of respiratory

gasses occurs. respiratory bronchioles,alveolary duct,alveoli.

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Summary of function-Nose/nesal cavity– warms,moistens and fiters air

it is inhaled.

Pharynx(Throat)-Passage way for air,leads to trachea.

Larynx-The voice box,where vocal chords are located.

Trachea(windpipe)-Tube from pharynx to bronchi rings of cartilage

provide stracture,keep the windpipe open. trachea lined with fine hairs called cilia which filter air before it reaches the lungs.

Bronchi-Two branches at the end of the trachea,each lead

to a lungs.

Bronchioles-A network of smaller branches leading from the

bronchi into the lungs tissue and ultimetly to lungs sacs

alveoliThe functional respiratory units in the lungs

where gases(o2 and co2) are exchanged(enter and exit the blood stream)

The Bronchopulmonary segments are the

anatomic structural and functional unit of lung parenchyma, each ventilated by a segmental/tertiary bronchus

Bronchopulmonary segments

RIGHT LUNG BRONCHOPULMONARY SEGMENTS

Upper lobe Apical

anterior

posterior

Middle lobe medial

lateral

Lower lobe superior

Medial basal

Anterior basal

Lateral basal

Posterior basal

LEFT LUNG BRONCHOPULMONARY SEGMENTS

Upper lobe apical

anterior

posterior

Superior lingularInferior lingular

Lower lobe superior

Medial basal

Anterior basal

Lateral basal

Posterior basal

Gaseous exchange--a) In between blood vessels and lungs.

.b) In between blood vessels and body tissue –

Gaseous transport-Main function of blood is to transport the gases

in diffirent form.Transport of o2 -Most o2 is transported by

Hb(red pigment protein in erythrocytes),(97%)

o2 combine with hemoglobin to form oxyhemoglobin.As—

Hb + o2 Hbo2A small amount of o2 is transported in solution in

the blood plasma(3%) and other body fluid.

Transport of co2 --

Most co2 is transported as bicarbonate ions. First co2 bind with water to form carbonic acid.As- CO2 + H2O H2CO3

Then carbolic acid dissosiates to form hydrogen and bicarbonate ions.

As-- H2CO3 H+ + HCO3−

A small amount of co2 is transported by the hemoglobin molecules in the form of carbaminohemoglobin(HbCO3).

Co2 +Hb HbCO3 (23%)

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•Removal of inhaled foreign particles and infectious organisms•Olfaction (sensation of smell)•Warming and humidification of air (losing excessive heat)•Phonation•Filtration of blood at the pulmonary capillaries•Acting as a volume reservoir of blood•Metabolic functions of the pulmonary tissue

NON RESPIRATORY FUNCTIONS OF LUNG

Investigations of Respiratory System

A- Imaging- Plain CXR

A PA film provides information on the lung fields , heart ,mediastinum , vascular structures and the thorathic cage. additional information can be obtained from a lateral film.

• CT scan 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)

• Ultra sound of chest cavity; is sensitive to detect plural effusion , may also

be used to improve the diagnostic field of plural biopsy.

•Ventilation – perfusion scan; the main value of this technique is to detect pulmonary thrombi or embolism, a filling defect in the perfusion scan accompanied by preserved ventilation is highly suggestive of recent PE.

• Positron Emission Tomography PET scan;In new technology to investigate pulmonary

nodules , staging of mediastinal lymph nodes and distal metastasis.

•CT- pulmonary angiography Is widely available and gold standard to

diagnose PE.

B- Endoscopic Examinations;• Laryngoscopy; larynx may be inspected

directly with a mirror or indirectly with a laryngoscope.

•Bronchoscopy;The trachea , large bronchi and lung segments

can all be inspected by either flexible or rigid bronchoscope.

Diagnostic indication of flexible bronchoscopy;- Suspected cases of Lung ca, - slowly resolving pneumonia, - pneumonia in the immunocompramised

patients, - interstitial lung disease, and - collecting lavage for AFB and culture in

suspected cases of TB , with –ve sputum.

• Mediastinoscopy; Through a small incision at the supra sternal

notch under GA, to get an access to the mediastinum.

- Other investigations •Plural aspiration and biopsy.•Sputum examination , for microbiological

( AFB, Culture, Gram stain ) and cytological examinations

•Pulse oximetry Allow a non invasive assessment of

peripheral O2 saturation, it provides a useful tool for monitoring those who are acutely ill or at risk of deterioration.

• Peak expiratory flow rate (PEF).Is measured by a maximum forced expiration

through a peak flow meter , it should be monitored regularly in asthmatic patients monitor response to therapy and disease control.

•Arterial blood gas analysisIt is heparinized blood taken from , the

radial , brachial and femoral arteries to check, PH, PaO2, PaCO2 and HCO3.

Type I respiratory failure; PaO2 < 8Kpa , PaCO2 either Normal or reduced.( hypoxia only), PH is normal.

Type II respiratory failure ; PaO2 < 8Kpa , PaCO2 >6Kpa

( hypoxia and hypercapnia), PH could be normal , high or low.

• Pulmonary Function Tests.Are used to aid diagnosis, assess functional

impairments and monitor treatment or progression of diseases.

Abbreviations used in RFTFEV1 forced expiratory volume in 1 secondFVC forced vital capacity VC vital capacityTLC total lung capacityFRC function residual capacityRV residual volumeTLco Gas transfer factor for carbon monoxideKco Gas transfer per unit lung volume.

• FEV1 is disproportionately reduced in obstructive lung disease ( asthma, COPD, bronchial obstruction) and the ratio of FEV1/ VC will be <70%. When there is an airflow obstruction the test should be repeated following administration of inhaled or nebulised B2 agonist

( salbutamol) to see the reversibility to normal or >15% that would give the diagnosis of asthma .

FEV1 and VC will both reduce in restrictive lung disease (Pulmonary Fibrosis) that will make the FEV1/VC ratio , >80%.

Interesting facts about respiratory system--About half a liter of water /day is lost through

breathing.

Yawning bring more O2 to the lungs .

Our right lungs is larger then left lungs.

We breathe 13 pints of air every minute.

People under 30 take in double the amount of O2 in comparison to someone who’s 80 years old.