The new advanced membrane gas exchanger.

Current membrane oxygenators are constructed for patients with a body surface under 2.2 m(2). If the body surface exceeds 2.

New prototype of femoral arterial SmartCannula with anterograde and retrograde flow.

Objectives: Femoral artery cannulation is routinely used in circulatory support scenarios for cardiorespiratory support in patients with acute cardiac and/or pulmonary decompensation. During prolonged perfusion, this may cause acute ischemia of the leg and, in the worst case, even amputation. The aim of this experimental study was to test a newly designed arterial cannula allowing proximal and distal blood flow.

Superior venous drainage in the "LifeBox": a portable extracorporeal oxygenator with a self-expanding venous cannula.

Background: In an experimental setting, the performance of the LifeBox, a new portable extracorporeal membrane oxygenator (ECMO) system suitable for patient transport, is presented. Standard rectilinear percutaneous cannulae are normally employed for this purpose, but have limited flow and pressure delivery due to their rigid structure. Therefore, we aimed to determine the potential for flow increase by using self-expanding venous cannulae.

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

Background: Recently, a compact cardiopulmonary support (CPS) system designed for quick set-up for example, during emergency cannulation, has been introduced. Traditional rectilinear percutaneous cannulas are standard for remote vascular access with the original design. The present study was designed to assess the potential of performance increase by the introduction of next-generation, self-expanding venous cannulas, which can take advantage of the luminal width of the venous vasculature despite a relatively small access orifice.

Temporary caval stenting improves venous drainage during cardiopulmonary bypass.

Objectives: Assess the benefit of temporary caval stenting for remote venous drainage during cardiopulmonary bypass (CPB).

Methods: Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm vs. a standard 28F wire armed cannula in trans-jugular fashion.

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

Objective: Assess the performance of self-expanding venous cannulas for routine use in open-heart surgery.

Methods: Prospective study in 100 unselected consecutive patients undergoing open-heart surgery with either remote or central smart venous cannulation.

Results: The study focuses on the 76 consecutive adult patients (mean age 59.

Establishing an association between a peri-operative perfusion score system (PerfSCORE) and post-operative patient morbidity/mortality during CPB cardiac surgery.

Background: To date, there is no quality assurance program that correlates patient outcome to perfusion service provided during cardiopulmonary bypass (CPB). A score was devised, incorporating objective parameters that would reflect the likelihood to influence patient outcome. The purpose was to create a new method for evaluating the quality of care the perfusionist provides during CPB procedures and to deduce whether it predicts patient morbidity and mortality.

Small access (30F) clinical central venous smart cannulation: is it adequate?

Objectives: To assess the performance of 45F vs. 36F smartcanula in CPB with gravity drainage alone.

Methods: Twenty patients were randomly assigned to two groups receiving for venous drainage a smartcanula which is collapsed over a mandrel for trans-atrial insertion into the inferior vena cava and expanded in situ to either 45F or 36F.

Comparing oxygen transfer performance between three membrane oxygenators: effect of temperature changes during cardiopulmonary bypass.

Recently, a new oxygenator (Dideco 903 [D903], Dideco, Mirandola, Italy) has been introduced to the perfusion community, and we set about testing its oxygen transfer performance and then comparing it to two other models. This evaluation was based on the comparison between oxygen transfer slope, gas phase arterial oxygen gradients, degree of blood shunting, maximum oxygen transfer, and diffusing capacity calculated for each membrane. Sixty patients were randomized into three groups of oxygenators (Dideco 703 [D703], Dideco; D903; and Quadrox, Jostra Medizintechnik AG, Hirrlingen, Germany) including 40/20 M/F of 68.

A novel device for reducing hemolysis provoked by cardiotomy suction during open heart cardiopulmonary bypass surgery: a randomized prospective study.

Since the inception of cardiopulmonary bypass (CPB), little progress has been made concerning the design of cardiotomy suction (CS). Because this is a major source of hemolysis, we decided to test a novel device (Smartsuction [SS]) specifically aimed at minimizing hemolysis during CPB in a clinical setting. Block randomization was carried out on a treated group (SS, n=28) and a control group (CTRL, n=26).

Prevention of cryoprecipitation during cardiopulmonary bypass in a patient with HIV-HCV co-infections.

Background: There are no guidelines for the management of patients with cryoglobulins during cardiopulmonary bypass (CPB) necessitating core hypothermia.

Objective: To evaluate a simple, pragmatic protocol of in vitro temperature-dependent cryoprecipitation of serum in patients with cryoglobulinemia before elective cardiac surgery with CPB.

Methods: A 44-year-old female patient was known for chronic hepatitis C and type III cryoglobulinemia.

A novel technique using echocardiography to evaluate venous cannula performance perioperatively in CPB cardiac surgery.

Objective: Transthoracic echocardiography (TTE) has been used clinically to disobstruct venous drainage cannula and to optimise placement of venous cannulae in the vena cava but it has never been used to evaluate performance capabilities. Also, little progress has been made in venous cannula design in order to optimise venous return to the heart lung machine. We designed a self-expandable Smartcanula (SC) and analysed its performance capability using echocardiography.

The Smartcanula: a new tool for remote access perfusion in limited access cardiac surgery.

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.

Vascular access for cardiopulmonary bypass procedures.

Since the initiation of cardiac surgery using cardiopulmonary bypass, little progress has been made concerning the design of catheters for vascular access. However, in the last few years, research in this specialized field has established that catheter performance not only depends on size but also on the catheter's design. The catheter's drainage hole surface area correlates with its performance, i.

Right atrial surgery with unsnared inferior vena cava.

Right atrial procedures require snaring the venous cannulas to prevent air entrapment in the venous line. In particular situations with complex congenital morphology and/or presence of severe pericardial adhesions the right atrial opening without the inferior vena cava cannula in the surgical field and without dissecting and snaring the inferior vena cava itself, might substantially facilitate the surgical technique, provided an adequate venous drainage is assured to avoid flow reduction or circulatory arrest. In several patients with congenital or acquired heart disease with potentially complicated venous drainage, like extracardiac Fontan procedure and tricuspid valve replacement, cardiopulmonary bypass was conducted either on normothermia (congenital lesions) or with mild hypothermia (acquired disease), with 3 l/min per m(2) flow index and venous drainage through femoral vein cannulation.

Limitations using the vacuum-assist venous drainage technique during cardiopulmonary bypass procedures.

Vacuum-assist venous drainage (VAVD) can increase venous blood return during cardiopulmonary bypass (CPB) procedures. However, the negative pressure created in the closed cardiotomy reservoir can be transmitted to the oxygenator if a nonocclusive or centrifugal arterial pump is used, resulting in bubble transgression (BT) from the gas to blood compartment of the oxygenator. We analyzed the vacuum pressure required to produce BT using an in vitro circuit including successively a closed reservoir, a pump (centrifugal or roller), and an oxygenator.

Miniaturization in cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) remains the key technology for more complex cardiac operations. The perfusion equipment used nowadays has seen tremendous progress since its introduction into clinical practice 50 years ago. However, overall, CPB is still far from perfect.

A prototype paediatric venous cannula with shape change in situ.

During cardiopulmonary bypass (CPB), venous drainage may be impeded due to small vessel and cannula size or chattering, thus, blood return to the heart-lung machine is reduced. We designed a self-expandable prototype cannula, which is able to maintain the vein open and overcome this problem and analysed its performance capability. This prototype and several other cannulae were tested using an access vessel diameter of 7 mm.

A new expandable venous cannula for minimal access heart surgery.

Background: During percutaneous cannulation, the diameter of the venous cannula is determined by the size of the access site. To limit this restriction, the Smart cannula (Cardiosmart Ltd., Fribourg, Switzerland) has been developed.

A new concept of integrated cardiopulmonary bypass circuit.

Objective: Standard cardiopulmonary bypass (CPB) circuits with their large surface area and volume contribute to postoperative systemic inflammatory reaction and hemodilution. In order to minimize these problems a new approach has been developed resulting in a single disposable, compact arterio-venous loop, which has integral kinetic-assist pumping, oxygenating, air removal, and gross filtration capabilities (CardioVention Inc., Santa Clara, CA, USA).

[Long-term mechanical circulatory support for terminal cardiac insufficiency refractory to medical treatment].

Constant progress has been made over the years in order to improve the performance of mechanical circulatory support devices. After the introduction of portable blood pump systems into clinical practice, we now study the performance characteristics of totally implantable mechanical circulatory support systems which do not require percutaneous drive lines or percutaneous electrical wiring. As a matter of fact, transcutaneous energy transfer is now achieved by induction, and pump controller performance read-out and pump parameter adjustment is performed by telemetry.

[Paediatric mechanical cardiac assistance].

The mechanical cardiac assistance, once limited only to the adult patients, is now progressively extended to the paediatric population, including neonates. Currently for children with cardiorespiratory insufficiency requiring for a mechanical assistance there are available several options: Intra-Aortic Balloon Pump, Extra-Corporeal Membrane Oxygenation (ECMO) et le Ventricular Assist Device. From April 1999 in our Department of Cardiovascular Surgery at CHUV 8 children, including 4 neonates, have been treated with ECMO.

[ECMO and cardiopulmonary support].

ECMO (extracorporeal membrane oxygenation) may be viewed as a prolonged cardiopulmonary bypass allowing for a prolonged cardio-respiratory support. Since its introduction in the 60's, its indication has expanded from acute respiratory failure to acute cardiac failure refractory to conventional treatments. The target group involves mainly those patients presenting with a cardiogenic shock following cardiac surgery or acute myocardial infarction.

Flow dynamic comparison of peripheral venous cannulas used with centrifugal pump assistance in vitro.

Because of the risk of vein collapse, the benefits of using a centrifugal pump to assist venous drainage for cardiopulmonary bypass are limited when the tips of peripheral cannulas are maintained within the vena cava. Using a mock circuit including 20 mm diameter latex tubing to mimic a vena cava, we compared the performance of 6 commercially available peripheral venous cannulas and attempted to determine potential factors influencing maximal flow drainage before vein collapse. A close correlation was observed with the total hole area of the cannula.