1. A simple technique to perform combined ultrafiltration
Francisco A Portela, MD, Alberto Pensado, MD, Amelia Sánchez, MD, Rita Español, RN, Claudio Zavanella, MD 
The Annals of Thoracic Surgery 
Volume 67, Issue 3, Pages (March 1999)
DOI: /S (98)

2. Fig 1
Conventional ultrafiltration circuit, from the arterial cannula through line C (316″) toward the venous reservoir. Ultrafiltration starts at the begining of the rewarming period until the end of bypass, while line M remains closed.
The Annals of Thoracic Surgery  , DOI: ( /S (98) )

3. Fig 2
Modified ultrafiltration circuit. At the end of bypass, the stopcock in line M is opened and line C is clamped. The bypass line of the arterial filter is unclamped and the filter excluded from the circuit. During modified ultrafiltration, blood circulates retrograde from the arterial cannula through line M, to the cardioplegia line, which goes to the right atrium. Contraction of the intravascular volume is compensated by slowly replacing blood from the venous reservoir.
The Annals of Thoracic Surgery  , DOI: ( /S (98) )