(5) The second tube in the drainage bottle is a vent for the escape of any air
drained from the lung. If suction is ordered, it is attached here.
(6) Bubbling at the end of the drainage tube may or may not be visible.
Bubbling may mean persistent air leaking from the lung or a leak in the system.
(7) The water level in the bottle fluctuates as the patient breathes. It rises
when the patient inhales and lowers when the patient exhales.
(8) Since fluid drains into this bottle, be certain to mark the water level prior
to opening the system to the patient. This will allow correct measurement of patient
d. The Two-Bottle Water-Seal System.
(1) The two-bottle system consists of the same water-seal bottle plus a fluid
(2) Pleural fluid accumulates in the collection bottle, and not in the
water-seal bottle (as in the single-bottle system).
Drainage depends upon gravity or the amount of suction added to the
When suction is added, it is connected at the vent tube in the water-seal
e. The Three-Bottle Water-Seal System.
(1) This system consists of the water-seal bottle, the fluid collection bottle,
and a third bottle which controls the amount of suction applied.
(2) The third bottle, called the manometer bottle, has three tubes. One
short tube above the water level comes from the water-seal bottle. A second short tube
leads to the suction. The third tube extends below the water level and opens to the
atmosphere outside the bottle. It is this tube that regulates the suction, depending upon
the depth the tube is submerged. It is normally submerged 20 cm (7.6 inches).
(3) The suction pressure causes outside air to be sucked into the system
through the tube, creating a constant pressure. Bubbling in the manometer bottle
indicates the system is functioning properly.
f. Commercial Systems.
There are several disposable commercial drainage systems available. They
are plastic devices, divided into chambers for fluid collection, water-seal, and suction
control. Follow the manufacturer's instructions for commercial drainage systems used
at your facility.