Pharmacotherapy
-
Right ventricular failure (RVF) after cardiac transplant (CTX) or implantation of a continuous-flow left ventricular assist device (CF-LVAD) is associated with significant postoperative morbidity and mortality. A variety of modalities have been used to treat postoperative RVF, including management of volume status, intravenous inotropes and vasodilators, and right-sided mechanical support. Inhaled vasodilator agents are a unique treatment option aimed at minimizing systemic absorption by delivering therapy directly to the pulmonary vasculature. ⋯ Based on our assessment of the literature, we suggest that when RVF occurs in the setting of a normal pulmonary vascular resistance (PVR), traditional inotropic therapy (e.g., dobutamine) should be used. Conversely, if the PVR is elevated (> 250 dynes/sec/cm5 or 3 Wood units), or the patient has other evidence of a high right ventricular afterload (i.e., a transpulmonary gradient > 12 mm Hg), then an inhaled pulmonary vasodilator would be the preferred initial pharmacologic agent. Drug selection depends largely on the institution's capacity to safely prepare and administer the medication, along with formulary considerations, such as the high costs associated with inhaled iloprost and inhaled nitric oxide.
-
Because the pharmacokinetic evaluation of valproic acid (VPA) based on total drug concentration may be misleading in patients with hypoalbuminemia as a result of saturable protein binding and saturable metabolism, we sought to investigate the usefulness of therapeutic drug monitoring of unbound VPA concentration in a real-world clinical context, with a focus on clinically significant neurologic adverse outcomes. ⋯ This study showed that in the presence of hypoalbuminemia, high unbound VPA concentrations can be observed despite normal or low total VPA concentrations. It also demonstrated that high unbound VPA concentrations are associated with clinically significant neurologic adverse symptoms. Clinicians should be aware that unbound VPA concentration monitoring may be required in the presence of hypoalbuminemia.