Microemboli may be a cause of postoperative neurological morbidity. Improved detection of microemboli may lead to better strategies to minimize embolization and improve neurological outcomes. Transcranial Doppler may have limited sensitivity for very small microemboli. The Emboli Detection and Classification (EDAC) Quantifier offers increased sensitivity (10 μm) and potentially improved capability for microemboli monitoring. EDAC was used to measure microemboli in the cardiopulmonary bypass circuit during 33 pediatric heart operations. More microemboli were detected in the venous than the arterial line (median, 11,830 vs 1298). Venous microemboli tended to be larger in size than arterial microemboli (>40 μm; 59% vs 7%). Increased venous and arterial microemboli were seen at the onset of bypass; increased venous microemboli were also seen with clamp removal. Thousands of microemboli <40 μm are transmitted to pediatric patients during heart surgery. Initiation of bypass may be a key offender and may result from air in the venous line. Although the significance of microemboli remains unknown, increased awareness may lead to improved techniques to minimize microemboli, with improvement in neurological outcomes.
We describe the occurrence and distribution of gaseous microemboli with real-time monitoring in a pediatric cardiopulmonary bypass (CPB) circuit and in the cerebral circulation of patients using the Emboli Detection and Classification (EDAC) system and transcranial Doppler (TCD). Four patients (weights 3.2-13.8 kg) were studied. EDAC monitors were located on the venous line and on the postfilter arterial line to measure gaseous microemboli in the CPB circuit. TCD was used to measure high-intensity transient signals (HITS) in the middle cerebral artery. Before the initiation of CPB, EDAC detected gaseous microemboli in two cases when giving volume through the arterial line. At the initiation of CPB, gross air appeared in the venous line and gaseous microemboli were detected in the arterial line in all patients. EDAC detected a total of 3192-14 699 gaseous microemboli in the arterial line during the whole CPB period, more than 99% of which were smaller than 40 microns. After cessation of CPB, EDAC detected gaseous microemboli in the arterial line in all cases. The TCD detected HITS in two cases (25 and 315), and detected no HITS in two cases. We observed that the venous line acted as a principal source of gaseous microemboli, particularly when using vacuum-assisted venous drainage, and that a significant number of these gaseous microemboli smaller than 40 microns were subsequently transferred to the patient. Using EDAC and TCD together could strengthen the monitoring of gaseous microemboli in the extracorporeal circuit and cerebral circulation.
Over the past 6 years at Penn State Hershey, we have established the pediatric cardiovascular research center with a multidisciplinary research team with the goal to improve the outcomes for children undergoing cardiac surgery with cardiopulmonary bypass (CPB) and extracorporeal life support (ECLS). Due to the variety of commercially available pediatric CPB and ECLS devices, both in vitro and in vivo translational research have been conducted to achieve the optimal choice for our patients. By now, every component being used in our clinical settings in Penn State Hershey has been selected based on the results of our translational research. The objective of this review is to summarize our translational research in Penn State Hershey Pediatric Cardiovascular Research Center and to share the latest results with all the interested centers.
A 24-year-old female developed heart failure within four months of delivering her first child. Echocardiogram revealed a moderately dilated left ventricle with severely reduced systolic function. She continued to decompensate, requiring intubation and inotropic support. When the use of an intra-aortic balloon pump failed to stabilize the patient, the decision was made to place her on ECMO. The circuit consisted of a Quadrox D membrane oxygenator and a CentriMag centrifugal pump. After 11 days of support, the patient met the weaning criteria and was successfully removed from ECMO. She was discharged one month after her admission. The new technology available allows for ECMO to be considered as an earlier option for the treatment and management of these patients as a bridge to recovery.
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