ABSTRACT
The PediaFlow pediatric ventricular assist device (VAD) is a magnetically levitated turbodynamic pump under development for circulatory support of small children with a targeted flow rate range of 0.3-1.5 L/min. As the design of this device is refined, ensuring high levels of blood biocompatibility is essential. In this study, we characterized platelet activation during the implantation and operation of a second generation prototype of the PediaFlow VAD (PF2) and also performed a series of surgical sham studies to examine purely surgical effects on platelet activation. In addition, a newly available monoclonal antibody was characterized and shown to be capable of quantifying ovine platelet activation. The PF2 was implanted in three chronic ovine experiments of 17, 30, and 70 days, while surgical sham procedures were performed in five ovines with 30-day monitoring. Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays with and without exogenous agonist stimulation. Platelet activation following sham surgery returned to baseline in approximately 2 weeks. Platelets in PF2-implanted ovines returned to baseline activation levels in all three animals and showed an ability to respond to agonist stimulation. Late-term platelet activation was observed in one animal corresponding with unexpected pump stoppages related to a manufacturing defect in the percutaneous cable. The results demonstrated encouraging platelet biocompatibility for the PF2 in that basal platelet activation was achieved early in the pump implant period. Furthermore, this first characterization of the effect of a major cardiothoracic procedure on temporal ovine platelet activation provides comparative data for future cardiovascular device evaluation in the ovine model.
Subject(s)
Biocompatible Materials/metabolism , Heart-Assist Devices , Platelet Activation , Animals , Child , Equipment Design , Humans , Materials Testing , Prosthesis Implantation , SheepABSTRACT
Opioids are frequently used for the treatment of chronic pain, and patients taking high doses are at increased risk of complications and adverse opioid-related events. Ketamine is appealing as an opioid adjunct because of its lack of respiratory depression and potential prevention of hyperalgesia and central sensitization. We present a case in which a ketamine infusion was utilized over a 7-day period to provide rapid taper of a daily dose of 400 mg of morphine equivalents to less than one-third of that dose on discharge with unchanged pain levels and no symptoms of opioid withdrawal.