Artificial organs
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Pediatric patients with end-stage heart failure require mechanical circulatory support (MCS) just as adults do. In order to meet the special requirements for neonates' and infants' MCS, pediatric circulatory support devices must be compact with low priming volume, easily controllable with low flow, less traumatic for blood cells and tissues, and biocompatible with minimum anticoagulation. We have designed and developed a miniature rotary centrifugal blood pump, "TinyPump," with a priming volume of 5 mL, which has already demonstrated its controllable performance for low flow and durability in vitro. ⋯ In the early experiments, hemolysis and thrombi formation at the impeller bearing resulted in termination of the study. Subsequent modifications of the bearing design, pump housing design, and magnetic coupling force helped to minimize the hemolysis and thrombi formation, prolonging the survival duration of the Shiba goats to 2 weeks with minimum adverse effects on the blood components and organ functions. With further experiments and improvements in pump durability and hemocompatibility, the TinyPump can serve as a suitable circulatory support device for neonates and infants bridging to heart transplantation as well as to heart recovery.
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The insults sustained by transplanted livers (hepatectomy, hypothermic preservation, and normothermic reperfusion) could compromise hepatic function. Hydrogen sulfide (H₂S) is a physiologic gaseous signaling molecule, like nitric oxide (NO) and carbon monoxide (CO). We examined the effect of diallyl disulfide as a H₂S donor during hypothermic preservation and reperfusion on intrahepatic resistance (IVR), lactate dehydrogenase (LDH) release, bile production, oxygen consumption, bromosulfophthalein (BSP) depuration and histology in an isolated perfused rat liver model (IPRL), after 48 h of hypothermic storage (4 °C) in University of Wisconsin solution (UW, Viaspan). ⋯ Hepatic clearance (HC) of BSP was affected by cold storage of livers, but there were no noticeable differences between livers preserved with or without diallyl disulfide. Meanwhile, livers preserved in the presence of H₂S donor showed an enhanced capacity for BSP uptake (k(A) CON = 0.29 min⁻¹; k(A) UW = 0.29 min⁻¹ ; k(A) UWS = 0.36 min ⁻¹). In summary, our animal model suggests that hepatic hypothermic preservation for transplantation affects liver function and hepatic depuration of BSP, and implies that the inclusion of an H₂S donor during hypothermic preservation could improve standard methods of preparing livers for transplant.
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Case Reports
Rescue extracorporeal life support for acute verapamil and propranolol toxicity in a neonate.
Extracorporeal life support (ECLS) to manage acute antiarrhythmic drugs toxicity in neonates has never been reported. Here presented is a case of venoarterial extracorporeal membrane oxygenation support in a newborn with refractory low cardiac output as a result of acute Ca-channel and β-receptor antagonist toxicity for treatment of paroxysmal supraventricular tachycardia (SVT). ⋯ Weaning was possible on the 5th day after implant, once recovery of the left ventricular function and optimization of the antiarrhythmic medication were achieved. In neonates with severe but potentially reversible cardiac dysfunction caused by drug toxicity, ECLS can maintain cardiac output and vital organ perfusion while allowing time for drug redistribution, metabolism, and clearance.
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Therapy for recurrent focal segmental glomerulosclerosis (FSGS) in the renal allograft is largely based on case reports. The use of plasmapheresis alone (based on its effectiveness in children) appears less effective in adults, reaching a response rate of <40%. Recently, rituximab, an anti-CD20 monoclonal chimeric antibody, showed promising results as rescue therapy in plasmapheresis-resistant recurrent FSGS. ⋯ Complete remission of proteinuria occurred in two and partial remission in the other two patients whereas renal function improved or remained stable. During treatment and the follow-up period (18-60 months) no severe infectious complications were observed. Our data suggest that the combination of plasmapheresis and rituximab is an acceptable treatment in patients with post-transplantation recurrent FSGS.
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Extracorporeal membrane oxygenation (ECMO) is the ultimate treatment option to improve gas exchange and decrease the aggressiveness of mechanical ventilation in septic patients with uncontrolled severe lung failure. However, potential microbiological colonization of the artificial surfaces of membrane oxygenator (MO) remains a critical issue in patients with bacteremia. The current study investigates the risk of MO infection in 10 consecutive septic patients on long-term treatment with ECMO. ⋯ In the patient concerned, a diffuse, unaccountable bleeding diathesis had developed, which stopped after exchange of the MO. Analysis of clinical parameters showed that D dimers had increased and fibrinogen levels had decreased before exchange of this MO, but standard markers of infection had remained unremarkable. In conclusion, circuit infection may be a potential cause for unexplained clinical deterioration of patients on ECMO, which therefore should be considered as an indication for exchange of the device.