The Smart Canula<SUP>TM</SUP>: A New Tool for Remote Access Perfusion in Limited Access Cardiac Surgery

Abstract

Devices for venous cannulation have seen significant progress over time: the original, rigid steel cannulas have evolved toward flexible plastic cannulas with wire support that prevents kinking, very thin walled wire wound cannulas allowing for percutaneous application, and all sorts of combinations. In contrast to all these rectilinear venous cannula designs, which present the same cross-sectional area over their entire intravascular path, the smartcanula concept of "collapsed insertion and expansion in situ" is the logical next step for venous access. Automatically adjusting cross-sectional area up to a pre-determined diameter or the vessel lumen provides optimal flow and ease of use for both, insertion and removal. Smartcanula performance was assessed in a small series of patients (76 +/- 17 kg) undergoing redo procedures. The calculated target pump flow (2.4 L/min/m2) was 4.42 +/- 61 L/ min. Mean pump flow achieved during cardiopulmonary bypass was 4.84 +/- 87 L/min or 110% of the target. Reduced atrial chatter, kink resistance in situ, and improved blood drainage despite smaller access orifice size, are the most striking advantages of this new device. The benefits of smart cannulation are obvious in remote cannulation for limited access cardiac surgery, but there are many other cannula applications where space is an issue, and that is where smart cannulation is most effective.

Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases☆

“…Furthermore, remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. As a matter of fact the pump flows achieved in this consecutive series of adult patients are in 97% on or above target (mean 113%), and as a result, augmentation using centrifugal pumps or vacuum is unnecessary as previously reported for randomized experimental studies [3,8] and smaller series for specific indications [4,5,9]. It has also been shown previously in a study comparing self-expanding cannulas (access orifice 30 F) to classic two-stage cannulas (access orifice 48 F), that blood flows more than 10% above the target of 2.4 l/m 2 can be achieved without additional blood trauma [6].…”

“…Interestingly, there is increasing evidence, that venous cannulation relying on the 'collapsed insertion and expansion in situ' concept is not only beneficial in remote venous cannulation, where unmatched flow rates can be achieved with gravity drainage alone [4], but also for central cannulation [5,6]. The present study summarizes our recent experience with systematic use of self-expanding cannulas for both peripheral and central venous cannulation.…”

Superior flow for bridge to life with self-expanding venous cannulas

“…As reported previously, the selfexpanding venous cannulas [7][8][9][10] can be stretched and collapsed with a hollow mandrel, inserted into the venous vasculature over a guide wire through an access orifice similar to the size of the peripheral vein or even smaller [11] and expanded to its nominal diameter of 36 F within the vena cava (typical diameter in adults is >20 mm or 60 F) or to the available luminal width of the access vessel (typical diameter of the femoral vein is 8 mm or 24 F). Already at the iliac level, the vein diameter increases, and, therefore, the narrow segment of a well-positioned self-expanding cannula is relatively short.…”

“…We have previously reported the functional principles of the self-expanding venous cannulas mainly for applications with gravity drainage that is, open heart surgery and miniinvasive cardiac surgery [7][8][9][10]. Briefly, the self-expanding cannula can be stretched and collapsed with a hollow mandrel, inserted into the venous vasculature, for example, through a femoral vein, over a guide wire in open, semi-open or percutaneous fashion [11].…”

“…The present study was designed to assess the potential performance increase by the introduction of next-generation, self-expanding venous cannulas [7][8][9][10] despite a relatively small access orifice. In contrast to the previous reports about the self-expanding cannula, a readyfor-use centrifugal pump is an integral part of this set-up, hence providing, by definition, augmentation of venous drainage.…”