Bottle 1
- No water prime and acts purely as a collection reservoir for fluid
- Air from the pleural cavity passes into the second bottle
Bottle 2
- Has an underwater seal with tubing tip 2-3cm below the water
- Acts as a one way valve as in a classic one chamber system
Bottle 3
(Not Always Required)
(Not Always Required)
- Exists to provide and control negative pressure suction to the system
- 3 tubes attach to the top:
- First connects to bottle 2
- Second connects to the suction pump
- Third connects to the atmosphere and water prime, and controls the magnitude of suction
- Suction is applied to the bottle making the pressure more negative and entraining air from the second bottle
- The degree of suction is controlled by the depth of the 3rd tube in the water prime. If it is set to 10cm below the water, no more than - 10cm H2O of pressure can be applied to the bottle as below this air will be entrained from the atmosphere and will be seen bubbling through the water prime
