Chest physiotherapy and the distribution of ventilation

Area of Science:

• Pulmonary medicine
• Respiratory physiology

Background:

• Physiotherapy for thoracic injuries often uses unilateral breathing techniques.
• The effectiveness of these methods in altering ventilation and blood flow distribution is not well understood.

Purpose of the Study:

• To investigate whether unilateral breathing exercises can change ventilation and blood flow distribution in the lungs.
• To compare the effects of voluntary breathing techniques with passive positioning on lung function.

Main Methods:

• Bronchospirometry was performed on patients undergoing physiotherapy.
• Subjects were studied during attempts to alter breathing mechanics unilaterally, through suggestion under hypnosis, and by adopting different body positions.
• Ventilation and blood flow to each lung were measured.

Main Results:

• Unilateral breathing techniques, voluntary efforts, and hypnotic suggestions did not alter ventilation or blood flow distribution.
• Lying on one side (dependent positioning) consistently and significantly increased ventilation and blood flow to the lower lung.
• Passive positioning proved effective, while active or suggested methods were not.

Conclusions:

• Commonly applied physiotherapy techniques for unilateral breathing are ineffective in altering ventilation and blood flow distribution.
• Passive positioning, specifically lying on one side, is a predictable and effective method for modifying lung ventilation and blood flow to the dependent lung.