A new bladder allows kinetic venous augmentation with a roller pump

Abstract

Augmented venous drainage improves venous return during minimally invasive cardiac surgery. Two systems to augment drainage are common: in one, a centrifugal pump draws blood from the venous site and pumps it into a venous reservoir. In the other, suction is applied directly to a hard-shell venous reservoir. Both systems overcome the high resistance of the venous cannula when gravity alone is insufficient to provide adequate drainage. Both systems also have shortcomings: in the first approach, the centrifugal pump head can entrap large bubbles, reducing flow and requiring pump stoppage to remove them. Air from the venous line also can be broken up by the centrifugal pump into small bubbles that can pass through the pump head. The direct suction system in the second approach cannot use a closed-bag reservoir, and has the potential to introduce air into the arterial line. We have developed a new venous augmentation system for a closed venous reservoir that provides excellent suction control without the potential to introduce air into the arterial line. Our system replaces the centrifugal pump of the first approach with a roller pump controlled by the Better-Bladder, a new device with FDA 510(k) clearance for long-term pumping. The Better-Bladder is a length of medical tubing, processed to form a thin-walled, enlarged bladder that is sealed within a clear rigid housing. It acts as an in-line reservoir that provides compliance in the venous line and a noninvasive means to measure blood pressure at the pump inlet. The bladder housing can maintain a negative pressure set by the user that controls the degree of gravity drainage. Tests have shown that the Better-Bladder allows for safe, smooth pump control using a roller pump in the venous line.

Hypovolemia in Extracorporeal Life Support Can Lead to Arterial Gaseous Microemboli

“…The “Better‐Bladder” has been introduced by Tamari et al. for drainage flow control in roller pump‐based long‐term ELS . In our experiments, we used a centrifugal pump‐based ELS circuit and did not apply “Better‐Bladder” pressure‐guided servo pump control.…”

“…). The “Bigger Better‐Bladder” acts as a damper and consists of a flexible thin‐walled tubing situated in a rigid transparent housing . The air volume in the closed compartment between tubing and housing is adjustable and compliant.…”

Can minimized cardiopulmonary bypass systems be safer?

“…As described by Tamari et al, adding volume buffer capacity (i.e. ‘windkessel’) to the venous line by using the ‘Better Bladder’ can reduce pressure fluctuations at the inlet of roller or centrifugal pumps during kinetic-assisted venous drainage 19 and might, therefore, reduce patient embolic load and improve clinical neurological outcome.…”

Venous drainage - gravity or assisted?

“…KAVD is used in most cases with a centrifugal pump although the use of a roller pump has been reported 17 . The advantage of KAVD is that it can be used with both closed and open venous reservoirs.…”