In  the first instance the speed controller knob was quickly turned down to 0 rpm  and then back up to the appropriate level, bypass was re-established with  little delay.  The same action was taken at the  2nd occurrence of the same issue. On the 3rd occurrence the single  pump module was turned off and back on again, bypass was re-established, with  no subsequent recurrence, the patient was separated from bypass at the  conclusion of the surgery without incident. The pump module was then taken  out of service, and the manufacturer informed.

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