Current Issue of JECT
The premiere source of the most current research and information related to extracorporeal technology including Cardiopulmonary Bypass, Extracorporeal Life Support, Mechanical Assist Devices, and Perioperative Blood Management.
|Volume 49 / Issue 3 / September 2017||Contents|
Endothelial Glycocalyx and Cardiopulmonary Bypass
Gerard J. Myers, RT, CCP Emeritus; Julie Wegner, PhD, CP
Abstract: On the outer surface of a human cell there is a dense layer of complex carbohydrates called glycocalyx, also referred to as glycans or the sugar coating on the cell surface, which is composed of a complex array of oligosaccharide and polysaccharide glucose chains that are covalently bonded to proteoglycans and lipids bound to the cell membrane surface. Studies of an intact endothelial glycocalyx layer (EGL) have revealed a number of critical functions that relate the importance of this protective layer to vascular integrity and permeability. These functions include the following: stabilization and maintenance of the vascular endothelium, an active reservoir of essential plasma proteins (i.e., albumin, antithrombin, heparan sulfate, and antioxidants), a buffer zone between the blood (formed elements) and the surface of the endothelium, and a mechanotransducer to detect changes in shear stress that facilitate vascular tone. There have been numerous review articles about the structure and function of endothelial glycocalyx over the past two decades, yet there still remains a significant knowledge gap in the perfusion literature around the importance of EGL. Perioperative fluid management and gaseous microemboli can both contribute to the damage/ degradation of endothelial glycocalyx.Adamaged EGL can result in systemic and myocardial edema, platelet and leukocyte adhesion, fluid extravasation, and contributes to microvascular perfusion heterogeneity. Knowledge of the importance of endothelial glycocalyx will enable clinicians to have a better understanding of the impact of gaseous microbubbles, hyperoxia, and ischemic reperfusion injury during cardiac surgery. The purpose of this article is to provide an in depth review of the EGL and how this protective barrier impacts the microcirculation, fluid homeostasis, inflammation, and edema during cardiac surgery.
Keywords: glycocalyx, endothelial glycocalyx, cardiopulmonary bypass, gaseous, icroemboli, microbubbles, hemodilution, hyperoxia, volume loading, syndecan, eparan, CPB. JExtra Corpor Technol. 2017;49:174–181
Antifungal Extraction by the Extracorporeal Membrane Oxygenation Circut
Kevin M. Watt, MD, PhD; Michael Cohen-Wolkowiez, MD, PhD; Duane C. Williams, MD; Desiree K. Bonadonna, BSE, CCP, LP; Ira M. Cheifetz, MD; Dhiren Thakker, PhD; Daniel K. Benjamin, Jr., MD, PhD, MPH;
Kim L.R. Brouwer, PharmD, PhD
Abstract: Invasive candidiasis is common and often fatal in patients supported with extracorporeal membrane oxygenation (ECMO), and treatment relies on optimal antifungal dosing. The ECMO circuit can extract drug and decrease drug exposure, placing the patient at risk of therapeutic failure. This ex vivo study determined the extraction of antifungal drugs by the ECMO circuit. Fluconazole and micafungin were studied separately in three closed-loop circuit configurations to isolate the impact of the oxygenator, hemofilter, and tubing on circuit extraction. Each circuit was primed with human blood, and flow was set to 1 L/min. Drug was dosed to achieve therapeutic concentrations. Each antifungal was added to a separate tube of blood to serve as a control. Serial blood samples were collected over 24 hours and concentrations were quantified with a validated assay. Drug recovery was calculated at each time point: (Ct/Ci)*100, with Ct and Ci the concentrations at time 5 t and 1 minute, respectively. After 24 hours of recirculation, mean recovery of fluconazole in the ECMO circuit (95–98%) and controls (101%) was high. In contrast, mean recovery of micafungin was dependent on the time and circuit configuration. Recovery at 4 hours was only 46% when a hemofilter was in-line but was much higher when the hemofilter was removed (91%). By 24 hours, however, micafungin recovery was low in all circuit configurations (26–43%), regardless of the presence of a hemofilter, as well as in the controls (57%). In conclusion, these results suggest that micafungin is extracted by the ECMO circuit, which may result in decreased drug exposure in vivo.
Keywords: antifungal extraction, extracorporeal membrane oxygenation, fluconazole, micafungin. J Extra Corpor Technol. 2017;49:150–159
Cerebral Oximetry and Autoregulation during Cardiopulmonary Bypass: A Review
Nousjka P.A.Vranken; Patrick W. Weerwind; Nadia A. Sutedja; Ervin E. Severdija; Paul J.C. Barenbrug; Jos G. Maessen
Abstract: Postoperative neurological complications (PNCs) following cardiac surgery with cardiopulmonary bypass (CPB) is a detrimental complication, contributing to increased mortality rates and health care costs. To prevent intraoperative cerebral desaturations associated with PNC, continuous brain monitoring using near-infrared spectroscopy has been advocated. However, clear evidence for a defined desaturation threshold requiring intervention during CPB is still lacking. Since cerebral oximetry readings are nonspecific, cerebral tissue oxygenation values need to be interpreted with caution and in the context of all available clinical information. Therefore, maintaining an intact autoregulatory activity during CPB rather than solely focusing on regional cerebral oxygen saturation measurements will collectively contribute to optimization of patient care during CPB.
Keywords: cerebral autoregulation, cerebral oximetry, cardiopulmonary bypass, postoperative neurological complications. J Extra Corpor Technol. 2017;49:182–191
Bloodless Repair of Aortic Arch with Dual Aortic Cannulation in a Jehovah’s Witness Patient
Melinda S. Valleley, CCP, MPS; Kimberly R. Glogowski, CCP, MPS; Kim F. Duncan, MD; Andrea Dutoit, MD; Corinna Hagedorn, CCP, MPS
Abstract: Various methods for surgical repair of the aortic archare described throughout the literature with many focused on cannulation techniques and degree of systemic cooling in an effort to reduce postoperative morbidities. Despite advancements in techniques, this surgery is still often associated with higher levels of blood loss and subsequent allogenic blood transfusions. Although blood products can be safely transfused to the majority of patients undergoing repair of the aortic arch, the complexity and risk is further multiplied when the patient is of Jehovah’s Witness faith and refuses blood transfusions. This paper will detail our technique of surgical repair of the aortic arch in a Jehovah’s Witness patient with dual aortic cannulation and our multidisciplinary approach to avoiding blood products.
Keywords: Jehovah’s Witness, bloodless cardiac surgery, dual aortic cannulation, retrograde autologous prime. J Extra Corpor Technol. 2017;49:206–209
Heparin: Effects upon the Glycocalyx and Endothelial Cells
Bruce D. Spiess, MD, FAHA
Abstract: Unfractionated heparin (UFH) is the most widely used injectable medication in the United States. UFH is a poly-dispersed, relatively impure combination of many polysaccharides known as a glycosaminoglycan. It is used as the primary anticoagulant for heart surgery as well as for active treatment of deep venous thrombosis, vascular thrombosis, stroke, and many other potentially catastrophic clotting syndromes. Many perfusionists and cardiac team members know little of the biology of UFH other than its use for cardiopulmonary bypass. UFH is very similar to heparin sulfate, found on the surface of endothelial cells. Heparan sulfate protects endothelial surfaces from inflammatory attack and serves as a mechanotransducer for vascular shear. UFH and all glycosaminoglycans have far reaching pleotropic actions. This review elaborates on some of fascinating unique biology of these polysaccharides. Perhaps a number of the complex complications attributed to CPB are either caused by, or set up to occur by the complicated biology of UFH?
Keywords: CPB, anticoagulation, ischemia/reperfusion, platelets, thrombosis. J Extra Corpor Technol. 2017;49:192–197
The Effect of Autologus Blood Priming on Cerebral Oximetry in Congenital Cardiac Surgery Patients
Ashley Hodge, MBA, CCP, FPP; Apryl Cohen, BS, CCP; Peter Winch, MD; Dmitry Tumin, PhD; Jeffrey Burnside, BS, CCP, FPP; Todd Ratliff, BS, CCP; Mark Galantowicz, MD; Aymen Naguib, MD
Abstract: Hemodilution is one of the sequelae of cardiopulmonary bypass (CPB). Autologous blood priming (retrograde autologous priming [RAP]/venous antegrade priming [VAP]) and acute normovolemic hemodilution (ANH) may be effective techniques to minimize hemodilution. The primary objective of this study is to investigate the impact of RAP/VAP combined with ANH on changes in cerebral saturations. A retrospective analysis of 52 patients undergoing congenital cardiac surgery requiring CPB between July 2014 and March 2015 was performed. Bivariate analysis correlated RAP/VAP and ANH volumes. SrO2 change scores were regressed on all covariates using multivariable least-squares models. The average percent of circulating blood volume (CBV) removed during RAP/VAP was 21610%in the cyanotic group and 1565% in the acyanotic group (p 5.006). There was a decrease in SrO2 from 70 6 11% at baseline to 55 6 13% at CPB initiation, although this decrease did not differ by cyanosis (p 5 .668) or use of ANH (p 5.566). Bivariate correlation and multivariable regression analysis of the SrO2 change score further demonstrated no statistically significant correlation between percent of CBV removed during RAP/VAP or ANH and the magnitude of the decline in SrO2. RAP and VAP help minimize hemodilution at the onset of CPB. This study further supports the use of these techniques in a pediatric population by emonstrating declines in SrO2 during RAP/VAP were consistent among cyanotic and acyanotic, including those who underwent ANH.
Keywords: autologous prime, retrograde autologous priming, venous antegrade priming, cerebral oximetry, pediatric, cardiac surgery, congenital, cyanotic. J Extra Corpor Technol. 2017;49: 168–173
Is There a Relationship between Pressure Gradients through Contemporary Oxygenators and Immune Cell Proliferation during Cardiopulmonary Bypass? A Pilot Study
Roger D.P. Stanzel, PhD, MSc, BScH, CPC; Mark Henderson, CCP CPC
Abstract: There have been many advances in the perfusion equipment used for cardiopulmonary bypass (CPB) surgery. A key component, the membrane oxygenator, has had a number of modifications in recent years and a recent clinical evaluation demonstrated disparity in various aspects of device performance. One difference among oxygenators, which to-date has received little attention, was the impact on the patient’s immune cells, with some oxygenators producing a significantly greater increase in immune cell numbers after cross clamp. Such increases in immune cell proliferation may contribute to the development of a systemic inflammatory response (SIR), which has been demonstrated to have a negative impact on patient outcomes. Although factors contributing to immune cell proliferation during CPB are recognized to be multi-factorial, the goal of the current communication was to perform an ad hoc analysis of these raw data for evidence that pressure gradients through an oxygenator contributes to this outcome. Despite the observation that higher-pressure gradient oxygenators appeared to associate with increased immune cell proliferation, no correlation was detected in this analysis. This finding, however, provides further evidence for the complex nature of inflammation during CPB, which deserves ongoing discussion and investigation.
Keywords: cardiopulmonary bypass, perfusion, heart-lung machine, oxygenator, cardiac surgery, inflammation, transmembrane pressure, shear stress, neutrophils. J Extra Corpor Technol. 2017; 49:160–167
A 2015–2016 Survey of American Board of Cardiovascular Perfusion Certified Clinical Perfusionists: Perfusion Profile and Clinical Trends
Casey Turnage, PhD; Edward DeLaney, MBA, CCP; Bradley Kulat, BA, CCP; Ann Guercio, MBA, CCP; David Palmer, EdD, CCP; Carol Ann Rosenberg, MBA, CCP; Kyle Spear, MS, CCP; David Boyne, BS, CCP; Charles Johnson, BS, CCP; William Riley, MS, CCP
Abstract: To document the current perfusion workforce status and to anticipate the future demands of an ever-changing perfusion workplace environment, a valid survey is needed to help guide the future of the perfusion workforce. The American Board of Cardiovascular Perfusion (ABCP) sponsored a survey of Certified Clinical Perfusionist (CCP) demographic and clinical trends that was linked electronically to the 2015–2016 ABCP online recertification process. Of 3,875 eligible CCP’s, 3,056 (78.9%) responded to the survey. The 12 survey questions covered the topics of gender, age, education levels, years of clinical experience, annual clinical activity exposure, high fidelity simulation experience, recertification requirement satisfaction and professional activity requirement contentment. The results of the ABCP annual survey are being published in accordance with the ABCP’s commitment to establish and maintain interactive communication with the community of CCPs. The goal of this survey is to present the perfusion and health-care community with important statistics related to the current field of perfusion and establish trends to guide the future of perfusion.
Keywords: ABCP, CCP, online survey, questionnaire, clinical caseload, simulation, clinical trends. J Extra Corpor Technol. 2017;49:137–149
Use of Volatile Anesthetic Agent in Extracorporeal Circuit as a Cause of Break in Polycarbonate Connector–Lessons Learnt
Deepak Gowda, DNB; Rashmi K, BSc; Naveen Pandarinathan, MCh; Neelam Desai, MCh, DNB
Abstract: Mishaps, near misses, and lethal incidents are known to occur during cardiopulmonary bypass. We share one such rare case of break in polycarbonate connector because of the use of isoflurane in extracorporeal circuit and its successful management.
Keywords: cardiopulmonary bypass, polycarbonate, isoflurane, atrial septal defect. J Extra Corpor Technol. 2017;49:198–200
Left Ventricular Unloading during Peripheral Extracorporeal Membrane Oxygenator Support: A Bridge To Life In Profound Cardiogenic Shock
Paolo Centofanti, MD; Matteo Attisani, MD; Michele La Torre, MD; Davide Ricci, MD; Massimo Boffini, MD; Andrea Baronetto, MD; Erika Simonato, MD; Alberto Clerici, MD; Mauro Rinaldi, MD
Abstract: A limit of peripheral veno-arterial Extracorporeal Membrane Oxigenator (VA-ECMO) is the inadequate unloading of the left ventricle. The increase of end-diastolic pressure reduces the possibility of a recovery and may cause severe pulmonary edema. In this study, we evaluate our results after implantation of VA-ECMO and Transapical Left Ventricular Vent (TLVV) as a bridge to recovery, heart transplantation or long-term left ventricular assit devices (LVAD). From 2011 to 2014, 24 consecutive patients with profound cardiogenic shock were supported by peripheral VA-ECMO as bridge to decision. In all cases, TLVV was implanted after a mean period of 12.2 6 3.4 hours through a left mini-thoracotomy and connected to the venous inflow line of the VA-ECMO. Thirty-day mortality was 37.5% (9/24). In all patients, hemodynamics improved after TLVV implantation with an increased cardiac output, mixed venous saturation and a significant reduced heart filling pressures (p < .05). Recovery of the cardiac function was observed in 11 patients (11/24; 45.8%). Three patients were transplanted (3/24; 12.5%) and three patients (3/24; 12.5%) underwent LVAD implantation as destination therapy, all these patients were discharged from the hospital in good clinical conditions. In these critical patients, systematic TLVV improved hemodynamic seemed to provide better in hospital survival and chance of recovery, compared to VA-ECMO results in the treatment of cardiogenic shock reported in the literature . TLVV is a viable alternative to standard VA-ECMO to identify the appropriate long-term strategy (heart transplantation or long-term VAD) reducing the risk of treatment failure. A larger and multicenter experience is mandatory to validate these hypothesis.
Keywords: heart failure, cardiogenic shock, mechanical circulatory support. J Extra Corpor Technol. 2017;49:201–205