Respiratory activity sensors - respiratory sensors (RA sensors)

Respiratory sensors are designed to register the dynamics of change of respiratory activity (pulmonary respiration) indicators: frequency and depth of both thoracic and diaphragmatic breathing of a person, which may be either automatic (unconscious), or consciously controlled.

Thoracic breathing sensor is designed to register the dynamics of change in the tone of the intercostal muscles, therefore, it must be located in the upper part of the chest at the level of 2-3rd intercostal space.

Abdominal breathing sensor is designed to register the change of tone of the diaphragm, therefore, it must be located in the lower part of the chest at the level of 7-8th intercostal space.

Design features of RA sensor

In Rubicon polygraph:

  • Two identical sensors are used:
    • thoracic ("upper") breathing (marked "B" or "VDH");
    • abdominal ("lower") breathing (marked "H" or "NDH").
  • Gain ratio of 500.
  • Automatic and manual gain adjustment in the range of 1 - 64.
  • Type of sensor - pneumatic bellows.
  • Sensor casing consists of a tube with a diameter of 2.1 - 2.7 cm, 20 cm long (in a free state) - 25 cm (in stretched state) made of ecologically pure reinforced silicone. Ends of the tube comprise fasteners made of environmentally friendly photopolymer plastic. All fasteners are made of stainless steel.
  • Air duct of the sensor is a silicone tube of 125 cm (110 cm + 15 cm) in length. Elasticity of the material of the duct provides fixation on the connector for data collection and processing unit without the use of specialized fasteners.
  • The sensor lock in the form of a ball chain is 125 cm in length, made of nickel-plated brass. The sensor is additionally equipped with a similar ball-chain - extension of 25 cm in length with an adapter.

Note: In order to reduce discomfort caused by pressure of ball chain on the armpits, each sensor on request can be equipped with two silicone tubes of 25 cm in length, which should be put on a ball chain.

Specifics of RA sensor application

RESPIRATORY RATE - change of the number of breaths (inhale - exhale) per time unit.

RESPIRATORY DEPTH - change of respiratory cycle amplitude (gradual or formed).

BREATH HOLDING - inspiratory or expiratory, as well as both inspiratory and expiratory.

RATIO time of inhalation and exhalation time.

Baseline offset (up - down).