International pediatric perfusion practice: 2011 survey results

New cardiopulmonary bypass devices and new innovative methods are frequently reported in the literature; however, the actual extent to which they are adopted into clinical practice is not well known. We distributed an electronic survey to 289 domestic and international pediatric congenital surgery centers in an effort to measure attributes of current clinical practice. The survey consisted of 107 questions relating to program demographics, equipment, and techniques. Responses were received from 146 (51%) of queried centers and were stratified into five distinct geographic regions (North America, Central and South America, Oceana, Europe, and Asia). Most of the responding centers reported use of hard shell venous reservoirs. Closed venous systems were used at 50% of reporting centers in Central and South America as compared with only 3% in North America and 10% in Asia. Seventy-one percent of the programs used some form of modified ultrafiltration. Use of an arterial bubble detection system varied between 50% use (Central and South America) vs. 100% (North America and Oceana). "Del Nido" cardioplegia is more common in North America (32%) than any other continent, whereas Custodial HTK solution is much more prevalent in Europe (31%). Wide variation in practice was evident across geographic regions, suggesting opportunities for further investigation and improvement.

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.

Retrospective analysis comparing hollow fiber and silicone membrane oxygenators for neonates on ECMO

There is little information showing the use of microporous polypropylene hollow fiber oxygenators during extra-corporeal life support (ECLS). Recent surveys have shown increasing use of these hollow fibers amongst ECLS centers in the United States. We performed a retrospective analysis comparing the Terumo BabyRx hollow fiber oxygenator to the Medtronic 800 silicone membrane oxygenator on 14 neonatal patients on extracorporeal membrane oxygenation (ECMO). The aim of this study was to investigate the similarities and differences when comparing pressure drops, prime volumes, oxygenator endurance, and gas transfer capabilities between the two groups.

Cardiopulmonary bypass using argatroban as an anticoagulant for a 6.0-kg pediatric patient

A patient was born with transposition of the great arteries, double-outlet right ventricle, interrupted aortic arch, and a ventricular septal defect and underwent a Damus-Kaye-Stansel procedure with a modified Blalock-Taussig shunt at 14 days old. Three months later, this patient presented with hypoxia and bradycardia was found to have a thrombus present in the main pulmonary artery extending to right pulmonary artery. After initiation of thrombolytic therapy, the patient became severely hypoxic and required the institution of extracorporeal membrane oxygenation. As the result of unknown heparin resistance independent of adequate antithrombin III levels, argatroban therapy was used to achieve desired anticoagulation. The patient was taken to the operating room and converted to conventional cardiopulmonary bypass once adequate activated clotting times were achieved using argatroban. This case report summarizes the use of argatroban as an anticoagulant for a 6.0-kg pediatric patient undergoing cardiopulmonary bypass.

Assessing the brain using near-infrared spectroscopy during postoperative ventricular circulatory support

Due to many innovative techniques and technologies, the overall rate of survival for infants undergoing surgical repair of congenital cardiac malformations is excellent. Despite these excellent outcomes, neonates with hypoplasia of the left heart represent a very unique population, and pose difficult challenges for the entire team involved in care. Despite some centers reporting outstanding outcomes, overall rate of survival rate is reported at only 53 percent,1 and survivors often show neurodevelopmental deficits. Many attempts have been made to identify predictors of neurologic outcomes, with heavy concentration around the pre- and peri-operative periods. Little attention has been paid, however, to assessing how attempts at balancing the systemic and pulmonary circulation affect neurodevelopmental outcomes. In the past, we have reported excellent rates of survival with use of routine postoperative circulatory support to augment cardiac output.2,3 This strategy, nonetheless, is still widely debated. It seems plausible that, by augmenting cardiac output in the immediate postoperative period, cerebral perfusion and oxygenation can be optimized, thereby improving neurologic outcomes. In this review, we describe our experience to date in assessing neurological outcomes, and discuss whether outcomes are associated with cerebral saturation and extraction of oxygen during the period of postoperative circulatory assist.

Argatroban usage for anticoagulation for ECMO on a post-cardiac patient with heparin-induced thrombocytopenia

We report a post-Norwood Stage I patient requiring ECMO support using Argatroban as an anticoagulant following diagnosis of heparin-induced thrombocytopenia (HIT). A 2.6 kg female was born with hypoplastic left heart syndrome and underwent a Norwood Stage I operation on day 4 of life. The patient weaned off cardiopulmonary bypass with no complications and was routinely placed on a ventricular assist device (VAD) for 3 days. Heparin was infused at a rate of 16-32 IU/ kg/h to maintain an ACT of 160-180 seconds. Two days after VAD termination, the patient was placed on continuous veno-veno hemofiltration (CVVH). Shortly after CVVH, the patient was diagnosed with HIT and placed on an Argatroban infusion. Five days later, a VAD and subsequent ECMO was used because of decreasing left ventricular function, gross body edema, and poor renal function. This case report summarizes the use of Argatroban during VAD and ECMO support for a patient diagnosed with HIT.

Routine mechanical ventricular assist following the Norwood procedure—improved neurologic outcome and excellent hospital survival

BACKGROUND

Although excellent survival following the Norwood procedure for palliation of hypoplastic left heart syndrome (HLHS) is being achieved by some, most centers, especially the ones with small surgical volume and limited experience, continue to struggle with initial results. Survivors often showed evidence of significant neurologic injury. The early postoperative care is labor-intensive as attempts are made to balance the systemic and pulmonary circulation for these infants. We report our experience with routine use of mechanical circulatory assist to support the increased cardiac output requirements present following Norwood procedure.

METHODS

Eighteen consecutive infants undergoing Norwood operation for HLHS (Oregon Health & Science University [OHSU] 13; University of Louisville [UL] 5) were placed on a ventricular assist device (VAD) immediately following modified ultrafiltration in the operating room using the cardiopulmonary bypass (CPB) cannulas that were in the right atrium and the neoaorta. VAD flows were maintained at approximately 200 mL x kg(-1) x min(-1) and the patients were transported to the intensive care unit (ICU). Patients operated at OHSU also received neurodevelopmental testing before their Glenn procedure, approximately 4 to 6 months following their Norwood operation.

RESULTS

All patients were stable on VAD support and no attempt was made to balance the systemic and pulmonary circulation. The ventilator was manipulated to achieve systemic Pa0(2) between 30 and 45 mm Hg and PaC0(2) between 35 and 45 mm Hg. Evidence of hypoperfusion (increasing lactates) was managed by increasing the VAD flow. Lactates normalized [< 2 mmol/L]) by 1.8 +/- 1.1 days following surgery. Average time of VAD support was 3.1 +/- 1.0 (range, 2 to 5 days) and average time until chest closure was 3.4 +/- 1.5 (range, 2 to 8 days). There were two cases of postoperative bleeding (11.1%) requiring reexploration and one case of mediastinitis (5.5%) in a patient who has now gone on to successful Glenn. Sixteen of the eighteen patients survived (hospital survival mean 89% with a 95% confidence interval of 63.9% to 98.1%; 12/13 OHSU [92.3%]; 4/5 UL [80%]). Neurodevelopmental testing using the Mullen Scales of Early Learning and the Vineland Adaptive Behavior Scale were normal for all infants tested.

CONCLUSIONS

Routine postoperative use of VAD can support the increased cardiac output demands of infants following Norwood operation and results in a stable postoperative convalescence that does not require aggressive ventilator or inotrope manipulation. Although not a panacea, this strategy can simplify postoperative management, lead to excellent hospital survival, and possibly augment cerebral oxygen delivery, resulting in improved neurologic outcomes for this challenging group of patients.