Question: What action would you take if you notice that in the chamber of the hydraulic seal of a patient's chest drainage, the water rises on inspiration and descends on expiration? 
 Options:  <1> Observe possible system bids. <2> Check the pressure level of the suction gauge. <3> Milk the tubes for obstruction. <4> None, since it is a normal finding. <5> Check that the system is placed horizontally.
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