Safety Testing of Left Ventricular Vent Valves.

Vent vacuum relief valves (VRVs) are used to limit the negative pressure at the ventricular vent catheter tip as well as prevent reversal of blood flow and prevention of air embolism. The purpose of this study was to evaluate the performance of three commercially available ventricular vent valves. The negative pressure at which the vent valve opened was measured at the valve inlet using high-fidelity pressure transducers. Also, the flow rate at which air entrainment occurred due to valve opening was recorded. Using a 51.5 cm column of saline, the resistance for each valve was calculated. The mean ± SD opening negative pressures were -231.3 ± 35.2 mmHg for the Quest Medical valve, -219.8 mmHg ± 17.2 for the Sorin valve, and -329.6 · 38.0 mmHg for the Terumo valve. The red Quest Medical valve opened at a lower flow (1.44 ± .03 L/min) than the dark blue Sorin valve (2.93 ± .01 L/min) and light blue LH130 Terumo valve (2.36 ± .02 L/min). The Sorin valve had the least resistance of 34.1 dyn-s/cm, followed by the Terumo LH130 valve resistance of 58.1 dyn·s/cm5, and the Quest Medical VRV-II valve with a resistance of 66.5 dyn·s/cm. We found that the valves are significantly different in the negative pressure generated. Understanding the limitations of these devices is important to reduce the occurrence of adverse events associated with venting and to select the best device for a specific clinical application.

Apicoaortic Valve Conduit for a Patient with Aortic Valve Stenosis and Patent Coronary Bypass Grafts Using Cardiopulmonary Bypass.

In adults over 65 years of age, aortic valve stenosis has been found to be present in 2-9% within this group. Furthermore, aortic valve replacements in patients whom have had a previous coronary artery bypass grafting surgery have a mortality rate as high as 18%. A non-conventional effective surgical approach of bypassing the aortic valve by inserting an apicoaortic valve conduit (AVC) connecting the left ventricular apex to the descending thoracic aorta has been previously documented. We describe the case of a successful implantation of an AVC in a 64-year-old Caucasian male using cardiopulmonary bypass.

Predicting adult perfusion practice trends and the adoption of evidence-based practice.

In an effort to provide optimal patient care, perfusionists should rely on information provided by current research. Present statistics, however, document a substantial underuse of evidence-based clinical practice and therapies not only in perfusion, but throughout the entire medical field. This investigation applied a statistical method--binomial proportion analysis--to aid in uncovering the trends in perfusion practice from 2004 to 2011. Through the analysis of national adult perfusion practice surveys, the feasibility of using binomial proportion statistical analysis is assessed in its ability to track adult perfusion practice proportional differentials over time and evaluate the adoption and attitudes toward the compliance of evidence-based practice within the field of perfusion. Surveys conducted in 2004 and 2006 on adult perfusion practice in the United States--although not published--are compared with data obtained by a similar survey distributed in 2011 through an international perfusion network system and perfusion mailing system, Perflist and Perfmail. The increase of perfusionists who practice retrograde and antegrade autologous priming (R/A AP) seen from 2004 to 2006 (35-50%) was statistically significant (Z(cal) = -2.30, p < .05) and from 2006 to 2011 (Z(calc) = -5.23; p < .05). Although the increase in biocompatible circuit (BC) use by perfusionists from 2004-2006 (53-64%) was not statistically significant (Z(calc) = -1.69, p < .05), the use of BCs did continue to increase (86%) significantly from 2006 to 2011 (Z(calc) = -9.15, p < .05). Other trends were observed; however, statistical significance was variable. This investigation demonstrates that binomial proportion statistical analysis is an effective method of evaluating perfusion practice trends and adoptions based on increasing or decreasing perfusion population proportion compliance over time.

A technique for autologous priming of the veno-venous bypass circuit during liver transplantation.

Orthotopic liver transplantations (OLT) have been associated with significant blood loss and hemodilution, necessitating significant homologous blood component replacement. Increasing administration of homologous blood products has been found to be inversely related to patient and graft survival. Various methods to reduce the amount of blood products patients receive during OLT, such as antifibrinolytic therapy, thromboelastography-guided transfusion, phlebotomy, reduced central venous pressures intraoperatively, and the use of the veno-venous bypass (VVB) circuit, have been explored.The asanguineous priming volume of the VVB circuit increases the likelihood of the patient receiving homologous blood products due to hemodilution. It was reasoned that autologous priming of the VVB circuit in OLT surgery was a plausible adjunctive blood conservation technique given its application to the extracorporeal circuit during cardiac surgery. We describe our technique of modifying the VVB circuit for autologous priming. This technique adds minimal risk and a small amount of cost to the procedure, requires slightly more communication among members of the surgical team, and with proper sequencing, adds no additional length to the surgical procedure. It is recommended that this technique be considered for addition to the arsenal of blood conservation techniques when VVB is used during OLT.

Trends and emerging technologies in extracorporeal life support: results of the 2006 ECLS survey.

Extracorporeal life support (ECLS) is a procedure used to support the failing heart and/or lungs via a heart lung machine. Over 145 institutions perform this practice in the United States with more than 24,000 ECLS cases recorded. While many articles are published each year on common perfusion practice, little information is shared on emerging technologies in ECLS and common practices among perfusionists and ECLS specialists. This article presents our 2006 ECLS survey results and discusses emerging technologies and management topics new to the ECLS arena. ECLS specialists were asked to participate in an online survey. Two hundred twenty-two ECLS specialists responded. This survey suggests positive displacement roller pumps are still the leading pump used for ECLS 122/188 (64.9%). Silicone membrane oxygenators are used by responders 75% of the time for long-term use, while hollow fiber membrane oxygenators are used 44%. Forty-five percent of responders are using heparin or biocoated circuits exclusively, while 14.6% restrict their use to specific subpopulations. The most common coating is heparin coating (67.9%). Activated clotting time (ACT) management is still standard of care for coagulation monitoring (98%), while partial thromboplastin time (PTT) follows at 71.7%. The interquartile range for ACTs is 160-220 seconds and 160-200 seconds with active bleeding. This article suggests ECLS specialists are beginning to incorporate different technology into their practice, such as centrifugal pumps with hollow fiber oxygenators and coated-circuits.

Gravity separation of pericardial fat in cardiotomy suction blood: an in vitro model.

Fat emboli generated during cardiac surgery have been shown to cause neurologic complications in patients postoperatively. Cardiotomy suction has been known to be a large generator of emboli. This study will examine the efficacy of a separation technique in which the cardiotomy suction blood is stored in a cardiotomy reservoir for various time intervals to allow spontaneous separation of fat from blood by density. Soybean oil was added to heparinized porcine blood to simulate the blood of a patient with hypertriglyceridemia (> 150 mg/dL). Roller pump suction was used to transfer the room temperature blood into the cardiotomy reservoir. Blood was removed from the reservoir in 200-mL aliquots at 0, 15, 30 45, and 60 minutes. Samples were taken at each interval and centrifuged to facilitate further separation of liquid fat. Fat content in each sample was determined by a point-of-care triglyceride analyzer. Three trials were conducted for a total of 30 samples. The 0-minute group was considered a baseline and was compared to the other four times. Fat concentration was reduced significantly in the 45- and 60-minute groups compared to the 0-, 15-, and 30-minute groups (p < .05). Gravity separation of cardiotomy suction blood is effective; however, it may require retention of blood for more time than is clinically acceptable during a routing coronary artery bypass graft surgery.