Pathomechanics of thorax

1. PATHOMECHANICS OF THORAX
PRESENTED BY :
MANJIRI KULKARNI
2ND YEAR MPT
CARDIOPULMONARY SCIENCES

2. INTRODUCTION
• In many of the respiratory conditions, the normal physiology and
mechanics of respiration is altered.
• It may lead to anatomic changes in the structures and functions of the
respiratory system.

3. COPD

4. Damage to the airway and destruction to
the alveolar wall, leading to diminished
elastic recoil property.
Passive exhalation is ineffective in removing the air
from thorax, thus causing air trapping and
hyperinflation of lungs.
In static resting position, there is a balance
between elastic recoil of the lung pulling inward
and ribs spring outwards, which is altered in these
cases.
Due to this , an increase in the AP diameter Is
noted , along with the flattening of diaphragm,
due to which now the major inspiration is
performed by other inspiratory muscles.
Paradoxical breathing pattern is observed
because the abdomen is pulled inward
and upward during inspiration, which
leads to more demand for ventilation.

5. BRONCHIALASTHMA

6. Use of accessory muscles of inspiration and
expiration.
Substernal intercostal retractions during inspiration
Increased AP diameter.
Pulsus paradoxus.
Hyperresonant percussion note, diminished breath
sounds, wheeze and rhonchi.

7. BRONCHIECTASIS

8. Increased Respiratory Rate
Use of accessory muscles of inspiration and
expiration
Increased A-P chest diameter, (barrel
chest).
When it is primarily obstructive in nature :
Hyperresonant percussion note, diminished
breath sounds, rhonchi and wheeze.
1) Stimulation of peripheral
chemoreceptors (hypoxemia)
2) Decreased lung
compliance/increased rate
relationship
When it is primarily restrictive :
Bronchial breath sounds, crackles, dull
percussion note.

9. PNEUMONIA

10. Increased Respiratory Rate.
Decreased Chest Expansion.
Dull percussion note, bronchial breath sounds,
pleural friction rub, crackles and rhonchi.
FVC reduces.
FEVT reduces.
VC reduces.
RV reduces.

11. PLEURAL EFFUSION

12. Increased Respiratory Rate :
Activation of deflation receptors, J receptors
and irritant receptors.
Reduced chest expansion
Tracheal shift , dull percussion note,
diminished breath sounds.

13. ACUTE RESPIRATORY DISTRESS
SYNDROME

14. Increased Respiratory Rate
Substernal/ Intercostal Retractions
Mild to moderate ARDS – pH increases , Paco2
reduces , HCO3 slightly reduces.
Severe ARDS – pH reduces, Paco2 increases, HCO3
slightly increases.

15. LUNG CANCER

16. Increased Respiratory Rate
Large amount of sputum, sometimes blood stained.
Crackles, wheeze, or rhonchi can be present.
All lung volumes and capacities are decreased.

17. THANK
YOU