Abstract In neonates, extracorporeal membrane oxygenation (ECMO) is increasingly used for circulatory support, e.g., after cardiac surgery. For training purposes and for research, animal experiments are usually required, complicated by increasing social issues, high costs, and limited reproducibility. Therefore, we designed a mechanical neonatal mock circulation (NMC) model enabling pulsatility and various hemodynamic conditions commonly occurring in neonates. Connected to a flow and pressure reading interface, a computer assisted data management system was installed. A nonocclusive roller pump combined with stiff and elastic tubing segments (for aortic pressure regulation and venous capacity) as well as constant and variable resistance (and optionally a patent duct) are essential features of the NMC system. To show the investigational potential, we studied the influence of venoarterial and venovenous ECMO on the NMC performance during normal circulation, hypovolemia, high arterial resistance, the combination of both, and in low cardiac output. By assessing the significant effects of ECMO on the circulatory function of the NMC, its feasibility and investigational properties could be demonstrated.
We report about a term newborn with urea-cycle disorder with severe cerebral edema in which the pharmacological treatment was combined with venovenous hemodiafiltration (VVHDF) and therapeutic hypothermia. A 50h old boy was admitted at a NICU in an external hospital because of convulsions and respiratory failure. Initial metabolic workup showed ammonia 2320µmol/l and the boy was transferred to our hospital. Initial examination showed a ventilated newborn with hepatomegalia and severe hypotension and ammonia concentrations of 2391µmol/l under treatment with Arginin-HCL and Na-Benzoat. Cranial ultrasound (CUS) showed a cerebral edema with systolic peaks and a pulsatility index (PI) of 3.0. After placing of a dual lumen catheter in the right jugularian vein VVHDF was started. In addition neuroprotection was performed by cooling the boy to a rectal temperature of 33°C for the first 24h using CritiCool cooling therapy system. Then the boy was rewarmed stepwise to 36°C over the next 48h. Ammonia concentration was decreased during the first 3h to 830.4µmol/l by VVHDF and CUS showed a significant improvement of the cerebral blood flow. VVHDF was stopped 3h later at ammonia 224.3µmol/l. There was no rebound of hyperammonemia and CUS showed regular findings. The metabolic investigation revealed an Argininosuccinate lyase deficiency. After Extubation at day 10, the boy was discharged at day 38. The 2 months follow up showed an adequate neurological development despite the classic signs of metabolic stroke in MRI. Conclusion: Life-threatening cerebral edema in newborns with inborn urea-cycle defects can be treated effectively by the combination of VVHDF with therapeutic hypothermia.
Abstract: Venoarterial extracorporeal membrane oxygenation (ECMO) in neonates commonly needs neck vessel cannulation leading to ligation of right common carotid artery (RCCA) in some cases. Quantitative electroencephalography (EEG) measurements provide reproducible data of cerebral function. The aim of this case‐control study was to test whether ligation of the RCCA results in EEG changes after ECMO weaning. Ten mechanically ventilated neonates not treated with ECMO were eligible as control patients. Seven ECMO patients receiving similar sedoanalgesia were investigated during and after ECMO and RCCA ligation. Dominant frequency, absolute alpha, theta, delta, and total powers of right and left frontocentral and temporooccipital derivations were calculated. Dominant frequency did not differ among groups. Power was found to be significantly decreased in all frequency bands during ECMO. After weaning from ECMO, EEG differences between the ECMO and control groups disappeared in spite of permanent RCCA ligation. It is concluded that ligation of the RCCA per se does not result in quantitative EEG changes.
In posthypoxic circulatory failure, pulsatility of flow generated by mechanical support devices significantly influences outcome. Pneumatically driven assist devices can create highly pulsatile flow, but need large graft cannulas implanted by thoracotomy in children and neonates. Emergency application is therefore hindered. We conducted an in vitro study using neonatal mock circulation (NMC) to test whether an extracorporeal membrane oxygenation (ECMO) system driven by a commercially available pneumatic assist device also can be operated through commonly used neonatal neck vessel cannulas. Using the pneumatically operated Medos ventricular assist device (VAD) 10 ml ventricle along with the Jostra M8/HEC40 oxygenator/heat exchanger, a neonatal ECMO system was assembled and connected to the NMC by means of commercially available neonatal neck vessel cannulas. Effective ECMO flow, combined circulation flow, and circulation pressures were measured during various working settings (ventricle driving pressures [systolic/diastolic (mbar)]: low: +100/-25, moderate: +200/-50, high: +300/-99) and loading conditions (device working against 0, 50, and 100% native circulation flow). Additionally, maximum possible ECMO flow through various sizes of neonatal ECMO cannulas and resulting pressure gradients were assessed. High pressure settings were necessary to achieve 100 ml/kg/min pulsatile circulation flow in case of zero native circulation. With residual 30% native circulation flow, 100 ml/kg/min pulsatile circulation flow could be established by moderate pressure settings. Low preload or high systemic vascular resistance reduced ECMO flow markedly. We concluded that in the described setting a pneumatically driven neonatal ECMO system could be operated even through commonly used neonatal neck vessel cannulas. It was necessary to accept partial emptying of the artificial ventricle and tapering of driving pressures with increasing native circulation.
Abstract: The case of a 17‐year‐old male patient with severe end‐stage dilated cardiomyopathy and a large thrombus formation within the cavum of the left ventricle is reported. After an acute thrombectomia combined with a partial left ventriculectomy (Batista procedure), the patient was successfully treated with an appropriate left ventricular assist device (LVAD) system using a centrifugal nonocclusive pump (Biomedicus, Medtronic, Anaheim, CA, U.S.A.). Mechanical support was removed on Day 9, and the patient was discharged from the hospital on Day 19. The effectiveness of emergency mechanical support in patients with very unfavorable prognoses is discussed.
Despite the established success of surfactant application in neonates, the use of surfactant in older children is still a matter of discussion. We hypothesized that surfactant application in children with acute respiratory distress syndrome (ARDS) secondary to a pulmonary or systemic disease or after cardiac surgery improves pulmonary function. We also asked whether repeated treatment could further improve pulmonary function. To answer these questions, we measured oxygenation index (OI) and hypoxemia score after the first and after a second application of surfactant (50-100 mg/kg body wt) at least 24 h later. We enrolled 19 children (older than 4 weeks) for a retrospective chart review study, and six of them underwent cardiac surgery. Demographic data were extracted. OI and hypoxemia score were estimated before and 2 and 24 h after surfactant application. Lung injury score was calculated before and 24 h after surfactant application. Outcome measures included survival, duration of mechanical ventilation, and pediatric ICU and hospital stay. The median patient age was 9.0 (quarter percentile 3.7/25) months. The median weight was 8.4 (4.1/11.5) kg. The median lung injury score before the first surfactant application was 2.3 (2.3/2.6). Hospital duration and pediatric ICU stay for all patients was 31.0 (20.0/49.5) days and 27.0 (15.5/32.5) days, respectively. The duration of mechanical ventilation was 24.0 (18.5/31.0) days. The overall mortality was 53%. Twenty-four hours after the first surfactant application, pulmonary function significantly improved. The median OI was 14 (5.5/26) before and 7 (4.5/14.5) 24 h after surfactant application (P= 0.027). The hypoxemia score was 91.7 (69.9/154.2) before and 148.4 (99.2/167.6) 24 h after surfactant application (P = 0.0026). Seven children received a second application, which did not further improve pulmonary function. The lung injury score was not influenced by either surfactant application. We conclude that a single surfactant application improves pulmonary function in children with ARDS. A second application of surfactant showed no further benefit. Outcome was not affected in our study population.
