Usefulness of vacuum-assisted cardiopulmonary bypass circuit for pediatric open-heart surgery in reducing homologous blood transfusion

A Surgeon's Perspective on Blood Conservation Practice in Pediatric Cardiac Surgery

Blood conservation practice in pediatric cardiac surgery has not been consistently adopted as quality improvement in many centers despite known risks associated with allogeneic blood products, shortage of donors, and costs. There are many blood conservation strategies available which collectively minimize exposure to allogeneic transfusion by maximizing the use of autologous red cells. These strategies are safe, reproducible, and have been implemented in clinical practice collectively with great efficacy for all patient ages and complexity levels. Institutional commitment to a set guideline will improve their blood conservation practice and quality outcome. The purpose of this article is to provide early career and practicing congenital cardiac surgeons with practical information concerning blood conservation strategies which can be considered for implementation in any pediatric cardiac surgery program, and which may be of particular value in resource-limited programs.

Development of a cannula device for gas fraction removal in surgical drains

The development of low-traumatic surgical drains aimed at maximum possible separation of blood and air, is an important trend in modern medicine. The objective of this work is to create an inexpensive, user-friendly and low-traumatic dynamic blood aspiration system (DBAS). The system allows effective separation of blood and air when drawing blood from a wound under vacuum conditions required for blood aspiration. The operating principle of the system is to separate liquid and gas fractions of the blood-air mixture by modifying the blood intake cannula. The effect is achieved by applying the principles of centrifugal forces of a rotating blood-air flow combined with Archimedes lift forces.

American Society of ExtraCorporeal Technology: Development of Standards and Guidelines for Pediatric and Congenital Perfusion Practice (2019)

The development of standards and guidelines by professional societies offers clinicians guidance toward providing evidence-based care. The ultimate goals of standards and guidelines are to standardize care and improve patient safety and outcomes while also minimizing risk. The American Society of ExtraCorporeal Technology (AmSECT) currently offers perfusionists several clinical resources, primarily the Standards and Guidelines for Perfusion Practice; however, no document exists specific to pediatric perfusion. Historically, the development of a pediatric-specific document has been limited by available scientific evidence because of smaller patient populations, sample sizes, and variable techniques among congenital perfusionists. In the current setting of evolving clinical practices and increasingly complex cardiac operations, a subcommittee of pediatric perfusionists developed the Standards and Guidelines for Pediatric and Congenital Perfusion Practice. The development process included a comprehensive literature review for supporting evidence to justify new recommendations or updates to the existing AmSECT Adult Standards and Guidelines document. Multiple revisions incorporating feedback from the community led to a finalized document accepted by the AmSECT member and made available electronically in May 2019. The Standards and Guidelines for Pediatric and Congenital Perfusion Practice is an essential tool for pediatric perfusionists, serves as the backbone for institutionally based protocols, promotes improved decision-making, and identifies opportunities for future research and collaboration with other disciplines. The purpose of this article is to summarize the process of development, the content, and recommended utilization of AmSECT's Standards and Guidelines for Pediatric and Congenital Perfusion Practice. AmSECT recommends adoption of the Standards and Guidelines for Pediatric and Congenital Perfusion Practice to reduce practice variation and enhance clinical safety.

American Society of ExtraCorporeal Technology: Development of Standards and Guidelines for Pediatric and Congenital Perfusion Practice (2019)

The development of standards and guidelines by professional societies offers clinicians guidance toward providing evidence-based care. The ultimate goals of standards and guidelines are to standardize care and improve patient safety and outcomes while also minimizing risk. The American Society of ExtraCorporeal Technology (AmSECT) currently offers perfusionists several clinical resources, primarily the Standards and Guidelines for Perfusion Practice; however, no document exists specific to pediatric perfusion. Historically, the development of a pediatric-specific document has been limited by available scientific evidence due to smaller patient populations, sample sizes, and variable techniques among congenital perfusionists. In the current setting of evolving clinical practices and increasingly complex cardiac operations, a subcommittee of pediatric perfusionists developed the Standards and Guidelines for Pediatric and Congenital Perfusion Practice. The development process included a comprehensive literature review for supporting evidence to justify new recommendations or updates to the existing AmSECT Adult Standards and Guidelines document. Multiple revisions incorporating feedback from the community led to a finalized document accepted by the AmSECT membership and made available electronically in May 2019. The Standards and Guidelines for Pediatric and Congenital Perfusion Practice is an essential tool for pediatric perfusionists and serves as the backbone for institutionally based protocols, promotes improved decision-making, and identifies opportunities for future research and collaboration with other disciplines. The purpose of this manuscript is to summarize the process of development, the content, and recommended utilization of AmSECT's Standards and Guidelines for Pediatric and Congenital Perfusion Practice.

Comparison of three infant venous reservoirs with vacuum-assisted venous drainage during varying levels of cardiotomy suction

BACKGROUND

Vacuum-assisted venous drainage has gained widespread use within the pediatric perfusion community for use during cardiopulmonary bypass. It is questioned whether its efficiency may be compromised with application of excessive cardiotomy suction to the infant hard-shell venous reservoir. An in vitro simulation circuit was used to research this phenomenon. A comparison of three different infant hard-shell venous reservoirs also took place to determine if one reservoir type was more advantageous when handling cardiotomy suction. The reservoirs tested were the Maquet VHK 11000, Medtronic Affinity Pixie, and Terumo Capiox FX05.

METHODS

The in vitro simulation circuit consisted of a 1 L reservoir bag that was cannulated at one access point with an Edwards Lifesciences 10Fr aortic cannula and the other access area with an Edwards Lifesciences 10Fr right angle venous cannula and 12Fr right angle venous cannula that were joined together. Key points of measurement and response variables were the pressures on the connection of the venous cannulas, inlet of the venous reservoir, and flow through the venous line. Vacuum was applied and manipulated with a Maquet VAVD Controller to settings of -20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg, and -60 mmHg. Cardiotomy suction was added at settings of 1 LPM, 2 LPM, 3 LPM, and 4 LPM. Values from each response variable were monitored and recorded. These data were utilized to compare the reservoirs with a random coefficient model for each response variable.

CONCLUSIONS

There is an adverse effect of excessive cardiotomy suction on the efficacy of vacuum-assisted venous drainage in infant hard-shell venous reservoirs. There is no significant difference between the VHK 11000, Pixie, and FX05 regarding their ability to handle this occurrence. An important discovery was that the FX05 showed a greater transfer of vacuum to the venous cannulas and reservoir inlet.

Hemolysis During Open-Heart Surgery With Vacuum-Assisted Venous Drainage at Different Negative Pressures in Pediatric Patients Weighing Less Than 10 kilograms

BACKGROUND

This study examined the degree of hemolysis during vacuum-assisted venous drainage at different negative pressures to identify an adequate negative pressure that provides effective venous drainage without significant hemolysis in open-heart surgery in children weighing less than 10 kg.

METHODS

Patients weighing less than 10 kg who underwent surgery for ventricular septal defect or atrial septal defect from 2011 to 2014 were enrolled. We used one of four negative pressures (20, 30, 40, or 60 mm Hg) for each patient. We measured haptoglobin, plasma hemoglobin, aspartate aminotransferase, and lactate dehydrogenase levels in the patients' blood three times perioperatively and determined the potential correlation between the change in each parameter with the level of negative pressure.

RESULTS

Forty-six patients were enrolled in this study (mean age: 7.1 ± 7.0 months, mean body weight: 6.1 ± 1.8 kg). There were no significant differences according to the degree of negative pressure with respect to patient age, body weight, cardiopulmonary bypass (CPB) time, aorta cross-clamping time, blood flow during CPB, or lowest body temperature. All parameters that we measured reflected progression of hemolysis during CPB; however, the degree of change in the parameters did not correlate with negative pressure.

CONCLUSION

In pediatric patients weighing less than 10 kg, the change in the degree of hemolysis did not differ with the amount of negative pressure. We may apply negative pressures up to 60 mm Hg without increasing the risk of hemolysis, with almost same the level of hemolysis using negative pressures of 20, 30, and 40 mm Hg for effective venous drainage and an ideal operative field during open-heart surgery.

180 ml and less: Cardiopulmonary bypass techniques to minimize hemodilution for neonates and small infants

Objective. To determine the efficacy of decreasing cardiopulmonary bypass (CPB) prime volume for neonates and small infants by using low prime oxygenators, small diameter polyvinyl chloride (PVC) tubing and removing the arterial line filter (ALF) in an effort to reduce intraoperative exposure to multiple units of packed red blood cells (PRBC). Methods. Two retrospective database studies comparing neonatal CPB prime volume were undertaken: Study 1 — A CPB circuit consisting of a 1/8 inch arterial line, a 3/16 inch venous line and a low prime oxygenator with 172 ml total circuit prime ( n = 74) was compared to a circuit with a 3/16 inch arterial line, a 1/4 inch venous line and a higher prime oxygenator with a 350 ml total circuit prime ( n = 74). Study 2 — The 172 ml circuit ( n = 389) was compared to a circuit that included an ALF and had a total circuit prime volume of 218 ml ( n = 389). Results. Study 1— of the 74 neonates and small infants whose CPB prime volume was 350 ml, 19 were exposed to two or more intraoperative exogenous PRBC units while only 3 neonates and small infants in the 172 ml prime group ( n = 74) received two or more units ( p = 0.0002). Study 2 — of the 389 neonates and small infants where an ALF was used (prime volume 218 ml), 54 were exposed to two or more exogenous PRBC units while only 36 of the 389 patients where an ALF was not used (prime volume 172 ml) received two or more units of intraoperative PRBCs ( p = 0.0436). Conclusion. Decreasing the neonatal and small infant extracorporeal circuit prime volume by as little as 46 ml resulted in significantly fewer multiple exposures to exogenous PRBC units. Perfusion (2007) 22, 327—331.

Perfusion technique for nonhaemic cardiopulmonary bypass prime in neonates and infants under 6 kg body weight

Background: Cardiopulmonary bypass (CPB) in neonates and infants is associated with significant haemodilution when priming of the CPB circuit is accomplished without transfusion of homologous blood components. The degree of haemodilution and, thus, the requirements for blood transfusion may be reduced when the CPB circuit is miniaturized without compromising patient safety.

Method: Between January 2002 and October 2003, selected neonates and small infants were operated on using a nonhaemic prime extracorporeal circuit. CPB priming volume could be reduced from 300 mL to 190 mL by using a dedicated neonatal CPB console with mast-mounted roller pump heads. Reduction of priming volume resulted from shortening of all CPB lines to the minimum, downsizing of all CPB lines, exclusion of unused CPB components, use of vacuum-assisted venous drainage and from close co-operation between the perfusionist, cardiac surgeon and anaesthesiologist. The reduction in priming volume was achieved without eliminating the arterial line filter as safety device.

Results: A total of nine patients weighing between 3.2 and 5.9 kg (mean 4.7 kg) and with a body surface area of 0.22 - 0.35m2 (mean 0.29m2) were operated on with the use of the modified neonatal CPB circuit and a nonhaemic prime. Bypass time varied from 38 to 167 min (mean 96 min). The mean haematocrit on CPB was 22.5% with a range of 17 - 29%. The postoperative course of all patients was uneventful.

Conclusion: A significant reduction in CPB priming volume makes nonhaemic prime CPB in neonates and small infants undergoing complex repair of congenital heart defects possible.

Vacuum-assisted drainage in cardiopulmonary bypass: advantages and disadvantages

Systematic review of vacuum assisted drainage in cardiopulmonary bypass, demonstrating its advantages and disadvantages, by case reports and evidence about its effects on microcirculation. We conducted a systematic search on the period 1997-2012, in the databases PubMed, Medline, Lilacs and SciELO. Of the 70 selected articles, 26 were included in the review. Although the vacuum assisted drainage has significant potential for complications and requires appropriate technology and professionalism, prevailed in literature reviewed the concept that vacuum assisted drainage contributed in reducing the rate of transfusions, hemodilutions, better operative field, no significant increase in hemolysis, reduced complications surgical, use of lower prime and of smaller diameter cannulas.

Blood Utilization in Neonates and Infants Undergoing Cardiac Surgery Requiring Cardiopulmonary Bypass

Neonates and infants undergoing cardiac surgery with cardiopulmonary bypass are exposed to multiple blood products from different donors. The volume of the bypass circuit is often as large as the patient’s total blood volume and asanguineous bypass primes are unusual. As a result, blood products are required for the cardiopulmonary bypass prime and are often used to treat the postbypass dilutional coagulopathy. We review clot formation and strength, cardiopulmonary bypass prime considerations, assessment of postbypass coagulopathy, component therapy use, ultrafiltration techniques, and use of antifibrinolytic medications. A combined approach including techniques to minimize the prime volume, utilization of ultrafiltration, administration of antifibrinolytics during surgery, and the proper treatment of the dilutional coagulopathy can limit the transfusion requirements.

Blood transfusion in pediatric cardiac surgery

The aim of the study is to measure the volume of homologous blood needed for one pediatric patient during his hospital stay. Over a 4-month period, all the patients operated upon with a blood prime or requiring blood transfusion during their hospital stay were included in this study.The cardiopulmonary bypass protocol associates a miniaturized bypass circuit, vacuum-assisted venous drainage, and microplegia. The volume of each blood product opened is known and the volume of blood product remaining, following the last transfusion, is measured. Data collected areas follows: patient weight; hemoglobin level before surgery,during bypass, and in intensive care after the last transfusion;time to extubation; and degree of inotropic support.Forty-six patients weighing 5.1 1.5 kg were included in this study. Cardiopulmonary bypass priming volume was 100 mL for patients up to 3.5 kg, 120 mL for patients between 3.6 and 7.5 kg, and 160 mL for patients between 7.6 and 8.6 kg. The volume of blood transfusion was 271 112 mL, hemoglobin level before surgery was 10.3 1.7 g/dL, hemoglobin level during surgery was 11.0 1.5 g/dL, and hemoglobin level after the last transfusion was 12.3 2.4 g/dL. Time to extubation was 12 3.3 h, and inotropic support was enoximone in 37 patients,whereas 6 patients needed enoximone and epinephrine.No patient needed reexploration for bleeding and one patient received a platelet transfusion.The mean blood transfusion volume was equivalent to 60% of the patient’s total blood volume (estimated to be 80 mL/kg).

Specific requirements for bloodless cardiopulmonary bypass in neonates and infants; a review

A miniaturized cardiopulmonary bypass circuit enables the safe performance, in selected pediatric patients, of bloodless open heart surgery. As the latest survival rates in neonatal and infant cardiac surgery have become satisfactory, investigators have concentrated upon the improvement of existing procedures. Institutional guidelines and multidisciplinary efforts undertaken in the pre- and postoperative periods are of great importance, concerning bloodless CPB and should be seriously pursued by all involved caregivers.

This review reflects upon the selective, most relevant requirements for success of asanguinous neonatal and infant CPB: acceptable level of hemodilution during the CPB, patient preoperative hematocrit value and volume of CPB circuit. We present an assessment of practical measures that were also adapted in our institution to achieve an asanguinous CPB for neonatal and infant patients.

Perfusionist strategies for blood conservation in pediatric cardiac surgery

There is increasing concern about the safety of homologous blood transfusion during cardiac surgery, and a restrictive transfusion practice is associated with improved outcome. Transfusion-free pediatric cardiac surgery is unrealistic for the vast majority of procedures in neonates or small infants; however, considerable progress has been made by using techniques that decrease the need for homologous blood products or even allow bloodless surgery in older infants and children. These techniques involve a decrease in prime volume by downsizing the bypass circuit with the help of vacuum-assisted venous drainage, microplegia, autologous blood predonation with or without infusion of recombinant (erythropoietin), cell salvaging, ultrafiltration and retrograde autologous priming. The three major techniques which are simple, safe, efficient, and cost-effective are: a prime volume as small as possible, cardioplegia with negligible hydric balance and circuit residual blood salvaged without any alteration. Furthermore, these three techniques can be used for all the patients, including emergencies and small babies. In every pediatric surgical unit, a strategy to decrease or avoid blood bank transfusion must be implemented. A strategy to minimize transfusion requirement requires a combined effort involving the entire surgical team with pre-, peri-, and postoperative planning and management.

Strategies to prevent intraoperative lung injury during cardiopulmonary bypass

During open heart surgery the influence of a series of factors such as cardiopulmonary bypass (CPB), hypothermia, operation and anaesthesia, as well as medication and transfusion can cause a diffuse trauma in the lungs. This injury leads mostly to a postoperative interstitial pulmonary oedema and abnormal gas exchange. Substantial improvements in all of the above mentioned factors may lead to a better lung function postoperatively. By avoiding CPB, reducing its time, or by minimizing the extracorporeal surface area with the use of miniaturized circuits of CPB, beneficial effects on lung function are reported. In addition, replacement of circuit surface with biocompatible surfaces like heparin-coated, and material-independent sources of blood activation, a better postoperative lung function is observed. Meticulous myocardial protection by using hypothermia and cardioplegia methods during ischemia and reperfusion remain one of the cornerstones of postoperative lung function. The partial restoration of pulmonary artery perfusion during CPB possibly contributes to prevent pulmonary ischemia and lung dysfunction. Using medication such as corticosteroids and aprotinin, which protect the lungs during CPB, and leukocyte depletion filters for operations expected to exceed 90 minutes in CPB-time appear to be protective against the toxic impact of CPB in the lungs. The newer methods of ultrafiltration used to scavenge pro-inflammatory factors seem to be protective for the lung function. In a similar way, reducing the use of cardiotomy suction device, as well as the contact-time between free blood and pericardium, it is expected that the postoperative lung function will be improved.