Complex protocol of cardiopulmonary bypass

Background. Innovative advances in cardiac surgery to reduce the negative impact of cardiopulmonary bypass (CPB) require a comprehensive solution. The ultimate questions of present interest remain the prevention of hypoxia, the composition of the priming volume of the oxygenator, the state of erythrocytes and their energy potential, the level of hemolysis, the pathogenetic approach to the correction of electrolytes during perfusion, as well as the biocompatibility of the extracorporeal circuit. The study aimed to create the protocol for cardiopulmonary bypass, which includes the possibility of reducing the negative effects of synthetic polymers of the extracorporeal circuit; reducing the hydrodynamic load on the tissue; carrying out a more physiological correction of the acid-base state; improving the energy potential of cells; correction of electrolyte balance during cardiopulmonary bypass ta­king into account the stages of the surgical operation. Materials and methods. The study included 225 patients who underwent cardiac surgery using cardiopulmonary bypass. The patients were divided into three groups. The first group consisted of 75 people, whose extracorporeal contour was treated with the adaptive composition by a special technique. After centrifuging the patient’s blood, serum was obtained, which was diluted in a solution of 0.9% NaCl and treated with the oxygenator circuit. The second group included patients (n = 75) in whom fructose-1,6-diphosphate (FPD) was used in the perfusion regimen. The drug was administered intravenously at a dose of 10 g at a rate of 10 ml/min in two stages: 5 g of FPD were injected immediately before the start of perfusion and 5 g before the patient was warmed up. The third group was the control group. Perfusion was performed using a membrane oxygenator in a non-pulsating blood flow mode with a prime of 1.3–1.6 L to achieve moderate hemodilution (Ht — 25 ± 2 g/L). A hyperosmolar priming volume with a total osmolarity of up to 510.6 mmol/L was used. The basic solutions were volutens, reosorbilact, mannitol 15%, Soda-buffer 4.2%. Hemogram (Hb, Ht, MCV, MCH, MCHC, RDWa, RDW%, hemolysis), oxygen transport: saturation of arterial (SaO2%) and venous blood (SvO2%), partial pressure of oxygen in arterial (PaO2) and venous blood (PvO2), oxygen delivery index (IDO2), oxygen consumption index (IVO2), oxygen extraction (O2ER), and oxygen extraction index (O2EI) were studied. The research of morphological changes in erythrocytes was carried out. Results. Our study aimed to develop and implement into practice an optimized cardiopulmonary bypass protocol based on the results obtained. The previous studies have shown that treatment of the oxy-genator circuit with the adaptive composition creates a protective layer of autoalbumin on the inner surface of the extracorporeal circuit, and the use of a drug with the active fructose-1,6-diphosphate ingredient during perfusion allows correcting hypophosphatemia, reducing the energy deficiency of the cells. In these two groups, in comparison with the control one, after CPB, there was a lower level of hemolysis, a lower number of echinocytes, and spherocytes. The three groups used the hyperosmolar priming ­volume. Before perfusion, there were the following indices: IDO2 — 332.00 ± ± 84.84 ml/(min • m2), IVO2 — 76.07 ± 28.34 ml/(min • m2), O2ЕR — 22.91 ± 6.33 %, O2EI — 22.47 ± 6.32 %, BE = –0.78 ± 2.13 mmol/L. At 10 min after CPB, there were the following indices: IDO2 — 579.7 ± 112.3 ml/(min • m2), IVO2 — 30.91 ± 13.31 ml / (min • m2), O2ER — 5.35 ± 2.07 %, O2EI — 5.26 ± ± 2.08 %, BE = 0.82 ± 2.03 mmol/L. IDO2 increased due to the oxygenator gas exchange, and the decrease in IVO2, O2ЕR, O2EI can be explained by the patient’s cooling. At the warming stage, there were the indices: IDO2 — 598.8 ± 114.9 ml/(min • m2), IVO2 — 108.10 ± 33.11 ml/(min • m2), O2ER — 18.04 ± 4.14 %, O2EI — 17.95 ± 4.15 %, BE = –0.11 ± 8.88 mmol/L. IDO2 — 305.7 ± 60.9 ml / min • m2), IVO2 — 77.15 ± 24.29 ml/(min • m2), O2ЕR — 25.36 ± 6.5 %, O2EI — 25.34 ± 6.5 %, BE = –0.36 ± 2.20 mmol/L. After CPB, the rate of diuresis was 11.88 ± 5.31 ml/kg/h, the relative hydrobalance after CPB was 9.67 ± 8.12 ml/kg. Our proposed protocol for cardiopulmonary bypass includes the basic points: 1) treatment of the oxygenator contour with the adaptive composition; 2) in patients with an initially low level of phosphorus, administration of the drug of fructose-1,6-diphosphate by the scheme; 3) the use of a hyperosmolar priming volume of the oxygenator; 4) correction of electrolytes taking into account the stages of cardiac surgery. Conclusions. The proposed procedure for the treatment of the extracorporeal oxygenator circuit is simple and affordable, improves the biocompatibility of the oxygenator. The use of a hyperosmolar priming volume avoids the volume load and provides an adequate gas transport function of the blood. The application of FPD makes it possible to reduce hemolysis and protect erythrocytes, correct electrolytes by taking into account the stages of operations and the peculiarities of CPB.

A Medical Mobile Application For Managing A Heart And Lung Machine During Cardiac Surgery

Background: Opened heart surgery with cardiopulmonary bypass (CPB) is a critical and complex procedure. A Heart-Lung machine (HLM) plays an important role for controlling the cardiopulmonary functions during the time of the surgery. Perfusionist must consider a variety of essential factors and calculate several cardiovascular parameters regarding the process of operating a HLM. To improving the quality of work, personal digital assistants must continually develop their skills and knowledge levels.Objective: The goal of this work is to construct a mobile application device that has a wide variety of functions which has the capacity to control targeted clinical planning and decision making for HLM users so to enable them to have control and evaluate the mobile application to user’s satisfaction. Methods: This smartphone app was constructed base on the ionic framework. The researchers have developed an unique algorithms for operating the HLM. The app was generated according to the phase of design, algorithm, validation, and user’s satisfaction of perfusionists.Results: The Project Researchers have officially assigned this medical mobile application with the name is Perfusion Assistant app that can be accessed and used effectively cross platform on iOS and Android. The application is comprised of five main categories which includes: a perfusion calculator, myocardial protection chart, drugs details, priming solution and parameters values. Result shown that all cardiovascular parameters did not significant differ from Perfusion Assistant app when compared to manual calculation. User’s satisfaction was at 3.64±0.76 in the first evaluation. After modification with feedback from experts, the app was evaluated with a 4.13±0.56 satisfaction. Conclusions: Perfusion Assistant app is an application designed in clinical planning and decision of HLM controlling for perfusionists and medical staff that work in an opened heart surgery arena. Perfusion Assistant app offers a variety of calculations related to CPB including blood flow rate, systemic vascular resistant, priming volume, and predicted hematocrit. Furthermore, Perfusion Assistant app provides a quick, easy access, and real-time application for CPB that user’s satisfaction was a good level.

Reply to Béranger et al., “Integration of Continuous Renal Replacement Therapy in a Meropenem Population Pharmacokinetics Model in Critically Ill Children”

We welcome Béranger et al.’s response to our recent publication (1), and we agree that the effect of continuous renal replacement therapy (CRRT) on pharmacokinetic parameters for meropenem (MEM) should be discussed. As Béranger et al. pointed out, extracorporeal membrane oxygenation (ECMO) was probably a component of the CRRT covariate, and it may have contributed to the increase in central volume of distribution. In fact, the circuit priming volume for ECMO can be several times higher than the pediatric patient’s blood volume, and hemodilution effect is inversely related to age (2).…

Pumping O2 with no N2: An Overview of Hollow Fiber Membrane Oxygenators with Integrated Arterial Filters

The advancement of cardiac surgery benefits from the continual technological progress of cardiopulmonary bypass (CPB). Every improvement in the CPB technology requires further clinical and laboratory tests to prove its safety and effectiveness before it can be widely used in clinical practice. In order to reduce the priming volume and eliminate a separate arterial filter in the CPB circuit, several manufacturers developed novel hollow-fiber membrane oxygenators with integrated arterial filters (IAF). Clinical and experimental studies demonstrated that an oxygenator with IAF could reduce total priming volume, blood donor exposure and gaseous microemboli delivery to the patient. It can be easily set up and managed, simplifying the CPB circuit without sacrificing safety. An oxygenator with IAF is expected to be more beneficial to the patients with low body weight and when using a minimized extracorporeal circulation system. The aim of this review manuscript was to discuss briefly the concept of integration, the current oxygenators with IAF, and the in-vitro / in-vivo performance of the oxygenators with IAF.

Is there any connection between method of priming extracorporeal circuit and cerebral oximetry results?

Objectives. To compare the influence of different priming techniques on cerebral oximetry results during CPB in adult patients.Methods. This study is a single-center retrospective review of data collected from adult patients who underwent isolated CABG with CPB between January and December, 2016. The patients were divided into two standardized groups with the sole difference between them being the method of priming CPB circuit: the first one was the group where we used our modified retrograde method of priming (n = 45) and the second one was the group with standard priming (n = 45). Hematocrit, hemoglobin, cerebral oxygenation were evaluated at the following points: beginning of the operation, start of CPB, cross clamping, 15, 30, 45 minutes and the end of CPB and the end of operation.Results. In the first group indices of cerebral oximetry were higher comparing to the second group at list of the 45 minutes of CPB (р < 0,001). For the first 15 minutes of CPB hematocrit was also higher in the first group. Priming volume and the need for blood transfusion or ultrafiltration were also smaller in the first group.Conclusion. Modified priming technique allows to maintain higher indices of cerebral oximetry, decreases volume overload and the need for blood transfusion comparing to standard technique.

A drive mechanism for a blood pump integrated in an oxygenator

The achievement of a low priming volume of the components in an extracorporeal perfusion system for neonatal and pediatric patients is an open research question. This paper presents a concept of a pump-oxygenator in which an oxygenator and a pulsatile blood pump are combined in one housing. For operation of the pump-oxygenator, a special actuating system for the pump process was designed. It consists of a piston pump which is directly coupled with a voice coil actuator (VCA). A servo positioning system was developed to assure the piston motion according to predefined reference trajectories. First experimental results indicate the feasibility of driving this blood pump with a VCA. In an in-vitro study, the pump produced mean flow rates of 60-900 mL/min with stroke frequencies in the range of 60-240 beats per minute.

Does the type of cardioplegia used during valve surgery influence operative nadir hematocrit and transfusion requirements?

Introduction: Myocardial protection is performed using diverse cardioplegic (CP) solutions with various combinations of chemical and blood constituents. Newer CP formulations that extend ischemic intervals may require greater asanguineous volume, contributing to hemodilution. Methods: We evaluated intraoperative hemodilution and red blood cell (RBC) transfusion rates among three common CP solutions during cardiac valve surgery. Data from 5,830 adult cardiac primary valve procedures where either four-to-one blood CP (4:1), del Nido solution (DN) or microplegia (MP) was used at 173 United States surgical centers. The primary outcome was the nadir hematocrit (Hct) during cardiopulmonary bypass (CPB), with a secondary outcome of total units of RBC transfused intraoperatively. Outcomes were assessed using mixed-effects regression, with controls for patient size, age, first Hct in the operating room, ultrafiltration volume, net bypass circuit priming volume, anesthesia and perfusion asanguineous volumes, cross-clamp and total procedure times, procedure type, reoperation, hospital, surgeon and twelve other patient and procedural variables. Results: A total of 2,641 patients received 4:1 (45.3%), 1,864 received DN (32.0%) and 1,325 received MP (22.7%). There were only slight differences in the central tendency (mean (SD)) for crude nadir Hct on CPB: 4:1, 25.5 (4.5), DN, 26.0 (4.6) and MP, 26.5 (4.7). After controlling for numerous operative and patient characteristics, the regression-adjusted estimate of the nadir Hct on CPB for MP was 26.2%, compared to 25.7% for 4:1 and 25.7% for DN; differences between MP and the other methods were statistically significant (p<0.01). Unadjusted mean RBC units transfused per patient was very similar across the groups (4:1, 2.2; MP, 2.3; DN, 2.4). Regression-adjusted estimates for the number of units of RBC transfused intraoperatively showed no statistically significant differences between CP methods. Conclusions: In patients undergoing cardiac valve surgery, the type of CP did not have a strong clinical impact on hemodilution or transfusion. Choice of a myocardial preservation solution can be made independently of its effect on intraoperative Hct.