Retrospective analysis of eliminating modified ultrafiltration after pediatric cardiopulmonary bypass.

Modified ultrafiltration (MUF) is a technique which is commonly used immediately post-cardiopulmonary bypass (CPB) for open heart surgery in children. There are many advantages of MUF, but there are also a number of less reported disadvantages. At our institution, after considering all of the available data, a decision was made to no longer perform MUF. The primary motivation being the simplified and miniaturized CPB circuit would reduce hemodilution, decrease our likelihood of reaching our transfusion trigger during CPB and, potentially, improve safety. This study reports the before and after data from this practice change. A total of 160 patients less than 8kg were studied over 38 months and divided into neonatal and pediatric cohorts. Parameters reported in this study include: demographics, hematocrit, blood product transfusion, hemostasis, hemodynamics and outcomes. Although retrospective, our analysis supports an advantage of preventing hemodilution (via circuit miniaturization) versus reversing hemodilution (via MUF) at our institution with the patient population we examined.

Recent Advances in Pediatric Cardiopulmonary Bypass.

There have been numerous recent advances geared specifically toward the practice of pediatric cardiopulmonary bypass (CPB). These advances include the development of the first oxygenator intended solely for the neonatal CPB patient; pediatric oxygenators with low prime volumes and surface areas, which allow flows up to 2 L/min; pediatric oxygenators with integrated arterial filters; and miniature ultrafiltration (UF) devices, which allow for high rates of ultrafiltrate removal. When used in combination with heart lung machines with mast-mounted pumps, these advances can result in significant decreases in CPB circuit surface areas and prime volumes. This may attenuate CPB-associated hemodilution and decrease or eliminate the need for homologous red blood cells during or after CPB. In addition to these equipment-related advances, changes in myocardial protection strategies and the technique of modified UF as it relates to these advances are discussed.

Cryoprecipitate and platelet administration during modified ultrafiltration in children less than 10 kg undergoing cardiac surgery.

UNLABELLED: The timing of blood product administration after cardiopulmonary bypass (CPB) may influence the amount of postoperative transfusion and chest tube output. We performed a retrospective study of a novel technique of administering blood products during modified ultrafiltration (MUF) in congenital cardiac surgery. A Control Group (CG; n = 55) received cryoprecipitate and platelets after modified ultrafiltration. The Treatment Group (TG; n = 59) received cryoprecipitate and platelets during MUF. Volumes of blood products transfused in the operating room, initial coagulation parameters in the cardiac intensive care unit, and first 24-hour chest tube output were recorded. Age (116 +/- 198 versus 84 +/- 91 days), weight (4.6 +/- 1.8 versus 4.5 +/- 1.4 kg), duration of bypass (121 +/- 50 versus 139 +/- 57 minutes), and Aristotle scoring (9.3 +/- 2.7 versus 9.1 +/- 3.1) were not significantly different when comparing the control and treatment groups, respectively. Intraoperative packed red blood cells (74.4 +/- 34.8 versus 79.3 +/- 58.0 mL/kg, p = .710), fresh-frozen plasma (58.3 +/- 27.1 versus 59.1 +/- 27.2 mL/kg, p = .849), cryoprecipitate (7.3 +/- 5.1 versus 8.6 +/- 5.9 mL/kg, p = .109), and platelet (19.0 +/- 14.6 versus 23.7 +/- 20.8 mL/kg, p = .176) administration were the same in the control and treatment groups, respectively. However, fibrinogen levels on arrival in the coronary intensive care unit were significantly higher (305 +/- 80 versus 255 +/- 40 mg/dL, p < .001) in the CG compared with the TG. Twenty-four-hour chest tube output was not significantly different but the CG (17.76 +/- 9.34 mL/kg/24 hours) was trending lower than the TG (19.52 +/- 10.94 mL/kg/24 hours, p = .357). In an attempt to minimize CPB-associated bleeding and transfusions, we changed our practice by adjusting the timing of blood product administration after patient separation from CPB. The goals of the change in practice were not measurably different in terms of shorter intraoperative times, fewer blood transfusions, or less chest tube output at our institution. KEYWORDS: congenital heart disease, modified ultrafiltration, cryoprecipitate, platelets, cardiopulmonary bypass.

Neonatal extracorporeal membrane oxygenation devices, techniques and team roles: 2011 survey results of the United States' Extracorporeal Life Support Organization centers.

In early 2011, surveys of active Extracorporeal Life Support Organization (ELSO) centers within the United States were conducted by electronic mail regarding neonatal Extracorporeal Membrane Oxygenation (ECMO) equipment and professional staff. Seventy-four of 111 (67%) U.S. centers listed in the ELSO directory as neonatal centers responded to the survey. Of the responding centers, 53% routinely used roller pumps for neonatal ECMO, 15% reported using centrifugal pumps and 32% reported using a combination of both. Of the centers using centrifugal pumps, 51% reported that they do not use a compliance bladder in the circuit. The majority (95%) of roller pump users reported using a compliance bladder and 97% reported using Tygon" S-97-E tubing in the raceway of their ECMO circuits. Silicone membrane oxygenators were reportedly used by 25% of the respondents, 5% reported using micro-porous hollow fiber oxygenators (MPHF), 70% reported using polymethylpentene (PMP) hollow fiber oxygenators and 5% reported using a combination of the different types. Some form of in-line blood monitoring was used by 88% of the responding centers and 63% of responding centers reported using a circuit surface coating. Anticoagulation monitoring via the activated clotting time (ACT) was reported by 100% of the reporting centers. The use of extracorporeal cardiopulmonary resuscitation (ECPR) was reported by 53% of the responding centers with 82% of those centers using a crystalloid primed circuit to initiate ECPR. A cooling protocol was used by 77% of the centers which have an ECPR program. When these data are compared with surveys from 2002 and 2008 it shows that the use of silicone membrane oxygenators continues to decline, the use of centrifugal pumps continues to increase and ECMO personnel continues to be comprised of multidisciplinary groups of dedicated allied health care professionals.

Complications relating to perfusion and extracorporeal circulation associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease.

The International Consortium for Evidence-Based Perfusion (www.bestpracticeperfusion.org) is a collaborative partnership of societies of perfusionists, professional medical societies, and interested clinicians, whose aim is to promote the continuous improvement of the delivery of care and outcomes for patients undergoing extracorporeal circulation. Despite the many advances made throughout the history of cardiopulmonary bypass, significant variation in practice and potential for complication remains. To help address this issue, the International Consortium for Evidence-Based Perfusion has joined the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease to develop a list of complications in congenital cardiac surgery related to extracorporeal circulation conducted via cardiopulmonary bypass, extracorporeal membrane oxygenation, or mechanical circulatory support devices, which include ventricular assist devices and intra-aortic balloon pumps. Understanding and defining the complications that may occur related to extracorporeal circulation in congenital patients is requisite for assessing and subsequently improving the care provided to the patients we serve. The aim of this manuscript is to identify and define the myriad of complications directly related to the extracorporeal circulation of congenital patients.

North American neonatal extracorporeal membrane oxygenation (ECMO) devices and team roles: 2008 survey results of Extracorporeal Life Support Organization (ELSO) centers.

In early 2008, surveys of active extracorporeal membrane oxygenation (ECMO) centers in North America were conducted by electronic mail regarding neonatal ECMO equipment and professional staff. Eighty of 103 (78%) North American ECMO centers listed in the Extracorporeal Life Support Organization directory as neonatal centers responded to the survey. Of the responding centers, 82.5% routinely used roller pumps for neonatal ECMO, and the remaining 17.5% used centrifugal pumps. Silicone membrane oxygenators were used by 67% of the respondents, whereas 19% used micro-porous hollow fiber oxygenators, and 14% used polymethylpentene hollow fiber oxygenators. Of the silicone membrane oxygenator users, 86% used the Medtronic Ecmotherm heat exchanger, 10% used the Gish HE-4 heat exchanger, and 4% used the Terumo Conducer device. Sixty-four percent of the responding centers used some form of in-line blood gas monitoring. Six percent of the centers used a bubble trap in the arterial line, and 5% used an arterial line filter. A bladder was used by 85% of the centers, and 4% of these used a mechanical bladder box for servo regulation; the remaining 96% used pressure servo regulation. An air bubble detector was used by 88% of the responding centers. A surface coating was used by 44% of the centers on all their neonatal ECMO patients. Thirty-one percent of the centers use an activated clotting time of 180-220 seconds. At 54% of the responding centers, perfusionists were involved with the ECMO program, registered nurses were involved at 70% of the centers, and respiratory therapists were involved at 46% of the centers. Compared with a 2002 survey, silicone membrane use is declining, and the use of centrifugal blood pumps and coated ECMO circuits is becoming more apparent. ECMO teams are still multidisciplinary, made up of combinations of registered nurses, respiratory therapists, and perfusionists.

Methylene blue-induced methemoglobinemia during cardiopulmonary bypass? A case report and literature review.

The guanylate cyclase (GC) and inducible nitric oxide (iNOS) inhibitor methylene blue (MB) has been used in cardiac surgery patients for the treatment of a variety of conditions. Methylene blue has been successfully used for the prevention and treatment of vasoplegia syndrome (VS) in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Vasoplegia syndrome occurs in up to 10% of cardiac surgery patients and is associated with poor clinical outcomes. Vasoplegia syndrome is described along with the results of studies that have shown benefits of MB in the treatment of VS. These studies include the use of MB prior to CPB, when added to the CPB prime and when given into the CPB circuit during the operation. We report a case of emergency CPB on a 55-year-old male with bacterial endocarditis, scheduled for an AVR/MVR who arrested on arrival to the operating room. Once on CPB the patient developed a profound hypotension despite normal to high pump flows, with low systemic vascular resistance (SVR), which was refractory to vasopressors--consistent with a diagnosis of VS. Unbeknownst to the perfusionist, the patient was treated with MB which was immediately followed by an apparent sudden arterial desaturation, despite oxygenator ventilation with 100% oxygen (O2), and development of severe metabolic acidosis. Troubleshooting the cause of the apparent desaturation and eventual diagnosis of a false indication of arterial oxygen desaturation and methemoglobinemia (MHgb) due to MB injection is described. Methemoglobinemia is explained as well as its presentation and treatment with MB. The importance of intraoperating room communication and knowledge of drug effects are discussed.

Evaluation of a preprimed microporous hollow-fiber membrane for rapid response neonatal extracorporeal membrane oxygenation.

Delays in initiating extracorporeal membrane oxygenation (ECMO) in the critically ill pediatric patient may lead to adverse outcomes. Maintaining a primed ECMO circuit can considerably reduce the initiation time. The predominant concerns precluding this practice are a decrease in oxygenator efficiency due to the saturation of microporous hollow fibers and compromised sterility when the oxygenator has been primed for 30 days. For institutions using a hollow-fiber oxygenator for ECMO, there are no data reporting pre-primed hollow-fiber oxygenator viability. This study reports the efficiency of oxygen transfer and the sterility of the Carmeda Minimax Plus (Medtronic, Inc, Minneapolis, MN) oxygenator after being crystalloid primed for 30 days. A total of 10 Minimax Plus oxygenators were tested for oxygen transfer in a laboratory setting utilizing fresh whole bovine blood. The control group (n =5) were tested immediately after priming. The test group (n =5) were oxygenators primed for 30 days with crystalloid solution and left stagnant until tested. Prior to testing, all oxygenators were circulated for 5 min and samples drawn to test for circuit sterility. Venous inlet saturations were manipulated to achieve three levels of testing: venous saturation (SvO2) of 55% for an oxygen challenge, SvO2 of 65% to comply with AAMI standards, and SvO2 of 75% to assess oxygen transfer rates and peak PaO2 achievement. Blood flow for all tests was maintained at 2 L/min with 1:1 blood to gas flow ratio and 100% FiO2. Samples were drawn pre- and postoxygenator at 1- and 6-hour time intervals to compute actual oxygen transfer values. All cultures from the test group priming solution produced no microbial growth after 30 days of stagnant prime. Average oxygen transfer values (ml/O2/min) for the control group after 1 hour of continuous use were 130.1+/-15.5 (@ 55% SvO2), 113.7+/-10.4 (@ 65% SvO2), 97.7+/-8.9 (@ 75% SvO2). After 6 hours, the average transfer values increased to 134.2+/-13.2 (@ 55% SvO2), 118.76+/-6.6 (@ 65% SvO2) and 98.9+/-8.3 (@ 75% SvO2). The average oxygen transfer values after 1 hour for oxygenators primed for 30 days were 114.9+/-10.0 (@ 55% SvO2), 112.4+/-8.2 (@ 65% SvO2) and 89.6+/-16.0 (@ 75% SvO2). After 6 hours of use, the average transfer values all decreased to 111.4+/-2.1 (@ 55% SvO2, p <0.05 versus control), 104.0+/-5.6 (@ 65% SvO2, p <0.05 versus control) and 88.4+/-3.2 (@ 75% SvO2, p <0.05 versus control). In conclusion, there was a decrease in the average oxygen transfer values for the test group after 6 hours versus the control. The modest loss of oxygen transfer ability observed can be considered acceptable due to the amount of surface area of the Minimax Plus oxygenator when used on a neonate, making it feasible to adopt the practice of prepriming the Minimax oxygenator for neonatal ECMO.