ProtekDuo percutaneous ventricular support system-physiology and clinical applications.

The ProtekDuo (LivaNova, London, UK) cannula is a dual-lumen device, typically inserted into the right internal jugular (IJ) vein through a percutaneous approach, with fluoroscopy or ultrasound guidance. When connected to a pump, such as the TandemHeart (LivaNova, London, UK) or CentriMag (Abbott, Pleasanton, CA, USA), it can function as a right ventricular (RV) mechanical circulatory support (MCS). When an oxygenator is also added [veno-pulmonary (V-P)], it can provide extracorporeal membrane oxygenation (ECMO) support. This review aims to provide a comprehensive overview of the device's physiology and clinical applications. In the setting of RV failure (RVF), the ProtekDuo cannula, with its outflow in the main pulmonary artery (PA), can bypass the failing RV, improving pulmonary flow, left atrial (LA) filling pressures, and left ventricular (LV) preload. This can also reduce ventricular interdependence and leftward shift of the interventricular septum that occurs in RVF. In this review, the key sections expand on the use of the ProtekDuo cannula in the management of critically ill patients, specifically, the use of ProtekDuo for RV myocardial infarction (MI) RVF, LV assist device (LVAD) implantation-associated RVF, RVF post-heart transplantation, temporary biventricular MCS as bridge to recovery (ECpella 2.0 or PROpella), biventricular support as bridge to recovery or decision, isolated LV failure, post lung transplantation (LT) care, and other miscellaneous clinical scenarios. ProtekDuo is an important tool in the armory of RVF management. The ProtekDuo system is expected to gain more popularity given its clear advantages such as groin-free approach allowing for mobility, easy percutaneous deployment, compatibility with various pumps and oxygenators, and the versatility to be integrated in numerous configurations. In an era of expanding MCS options, further research is needed to better understand the optimal tool for specific patient subsets.

Tranexamic Acid for Bleeding Management in Adult Patients on Extracorporeal Membrane Oxygenation.

This study described the outcomes of patients receiving topical, nebulized, endobronchial, or systemic tranexamic acid (TXA) for bleeding events while on extracorporeal membrane oxygenation (ECMO). We performed a single-center case series including adult patients >18 years old supported on either venovenous (VV) or venoarterial (VA) ECMO from January 1, 2014, to April 21, 2021. The primary outcome was hemostatic control defined as a composite of initial cessation of therapeutic interventions to mitigate bleeding or resumption of anticoagulation if previously held. Secondary outcomes included changes in transfusion requirements and lysis at 30-minute (LY30) values, venous thromboembolism (VTE) events, and seizures. In total, 47 patients were included for full analysis. There were 19 patients with surgical bleeds, 18 patients with medical bleeds, and 10 patients with multiple bleeds. Overall, initial hemostatic control was achieved in 79%, 67%, and 90% of patients, respectively. Pre- and post-TXA transfusion requirements were not significantly different ( p = 0.2), although the intraindividual change in median LY30 was -5.1% compared with baseline (95% confidence interval [CI], -12.4% to -1.5%, p = 0.005). The occurrence of VTE and seizures was relatively low and similar among patient bleeding groups. Tranexamic acid provided initial hemostatic control in roughly three quarters of patients with bleeding events on ECMO and side effects were infrequent.

Heparin Versus Bivalirudin for Anticoagulation in Adult Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis.

Extracorporeal membrane oxygenation (ECMO) poses unique thrombotic and hemorrhagic risks, and the optimal anticoagulant choice is unknown. We systematically searched Ovid EBM Reviews, Ovid Embase, Ovid Medline, Scopus, and Web of Science Core Collection for randomized-, crossover-, retrospective cohort-, or parallel-designed clinical studies of adult patients receiving ECMO that compared heparin recipients with bivalirudin recipients. Meta-analysis was performed with random-effects models. The ROBINS-I tool was used to assess the risk of bias. Six retrospective observational studies met the inclusion criteria for the qualitative summary. Five studies were suitable for meta-analysis. Those who received heparin were more likely to experience circuit-related thrombosis (odds ratio [OR] 2.05, 95% confidence interval [CI] 1.25-3.37, p = 0.005, I2 = 0%) and die (OR 1.62, 95% CI 1.19-2.21, p = 0.002, I2 = 0%) compared with those who received bivalirudin. There were no differences in major bleeding events between heparin and bivalirudin recipients (OR 1.83, 95% CI 0.55-6.09, p = 0.33, I2 = 82.7%). In retrospective settings compared with heparin anticoagulation, bivalirudin was associated with less circuit-related thrombotic events and greater survival in adults supported on ECMO, without contributing to more bleeding complications. Prospective controlled studies comparing heparin and bivalirudin in adult ECMO patients are warranted to corroborate these findings.

Sepsis-Induced Cardiomyopathy Reviewed: The Case for Early Consideration of Mechanical Support.

Sepsis-induced cardiomyopathy (SCM) is an increasingly recognized problem encountered in critical care medicine. It generally is characterized as a decrease in left, right, or biventricular ejection fraction followed by a recovery of function over a period of days to weeks. Venoarterial extracorporeal membrane oxygenation (ECMO) has been used for the treatment of adults with various etiologies of shock, including cardiogenic and septic shock. This review summarizes current pathophysiologic mechanisms leading to SCM and provides a detection and treatment algorithm for SCM, as well as a discussion about the rationale and recent clinical data surrounding the use of ECMO and other forms of mechanical circulatory support for SCM.

Hemodynamic Effects of an Increased Midodrine Dosing Frequency.

In practice, midodrine has been used to reduce IV vasopressor requirements and decrease ICU length of stay. However, recent publications have failed to show clinical success when midodrine was administered every 8 hours. One possible reason for the lack of clinical efficacy at this dosing interval may be the pharmacokinetic properties of midodrine that support a more frequent dosing interval. Here, we report our institutional experience with midodrine at a dosing frequency of every 6 hours. DESIGN: Single, quaternary academic medical center, retrospective, descriptive study. SETTING: Floor and ICU patients admitted to Mayo Clinic, Rochester, from May 7, 2018, to September 30, 2020. PATIENTS: Adult patients with an order for midodrine with a dosing frequency of "every 6 hours" or "four times daily" were eligible for inclusion. INTERVENTIONS: No intervention performed. All data were abstracted retrospectively from the electronic medical record. MEASUREMENTS AND MAIN RESULTS: Forty-four unique patients were identified that met inclusion criteria. Patients were an average of 65 years and 63.6% were male. The individual doses of midodrine ranged from 5 to 20 mg. Twenty-three patients (52.3%) were receiving IV vasopressors at the time midodrine was ordered every 6 hours. Vasopressor requirements decreased from an average of 0.10 norepinephrine equivalents 24 hours prior to the every 6-hour order to 0.05 norepinephrine equivalents 24 hours after an order for midodrine every 6 hour was placed. CONCLUSIONS: Increasing the dosing frequency of midodrine to every 6 hours may optimize its pharmacokinetic profile without compromising safety. This midodrine dosing frequency should be prospectively evaluated as a primary strategy for accelerated IV vasopressor wean.

Extended Duration Infusion of Hydroxocobalamin for Vasoplegic Rescue in Septic Shock.

Nitric oxide (NO) is a gaseous signaling molecule and a key endogenous mediator of vascular tone. Hydroxocobalamin (HCB) affects NO-mediated vasoplegia as (1) a direct inhibitor of nitric oxide synthase (NOS), thereby decreasing its production, and (2) by binding directly to NO and acting as a scavenger. HCB has been increasingly used in the treatment of refractory vasoplegia, particularly in cardiac surgery and liver transplant patients. Sepsis and septic shock are characterized by an increase in inducible NOS expression and activity with excessive NO production, resulting in endothelial dysfunction and profound systemic vasodilation. Therefore, a careful sustained reduction in NO burden represents a potential therapeutic target. Here, we present a case of refractory septic shock, which resolved after an extended duration infusion of high-dose HCB. We hope to foster further exploration regarding the safety, dosing, and efficacy of HCB when administered for vasopressor refractory septic shock.

Extended duration infusion of high-dose hydroxocobalamin for vasoplegic syndrome following cardiac surgery.

Vasoplegic syndrome occurs in 8% to 12% of cases that use cardiopulmonary bypass and carries a high mortality. Although the precise cause of this shock state has yet to determined, it is postulated to be related to abnormal nitric oxide (NO)-mediated dilatation of vascular smooth muscle resulting in arterial and venous vasodilatation. Since its first report in 2014, the off-label use of hydroxocobalmin as a rescue therapy for the treatment of refractory vasodilatory shock has gained attention with a mechanism thought to be primarily mediated by the scavenge, binding to, and prevention of the formation of NO. Importantly, no dose-finding study of hydroxocobalamin for the treatment of vasoplegic shock has been published. Consequently, dosing is extrapolated from the treatment of cyanide toxicity (5 g administered by intravenous infusion over 15 min) and the hemodynamic improvement only appears to persist for a few hours when administered as a bolus. Herein we describe twelve patients with vasoplegic shock following cardiac surgery that received an extended duration infusion of hydroxocobalamin administered over a median of 6 h and illustrate the rapidity and durability of the hemodynamic response encountered.