Extracorporeal Circulation System Research Articles

Air removal capacity of two different minimal invasive ECC systems: an in vitro comparison.

Minimally invasive extracorporeal circulation systems are developed to decrease the deleterious effects of cardiopulmonary bypass. For instance, prime volume and foreign surface area are decreased in these systems. However, because of the lack of a venous reservoir in minimized systems, air handling properties of these minimally invasive extracorporeal circulation systems may be decreased as compared to conventional cardiopulmonary bypass systems. The aim of this in vitro study is to compare the air handling properties of two complete minimized cardiopulmonary bypass systems of two manufacturers, of which one system is provided with the air purge control. In an in vitro study, two minimally invasive extracorporeal circulation systems, Inspire Min.I manufactured by Sorin Group Italia, Mirandola, Italy (LivaNova, London, United Kingdom) and minimized extracorporeal circulation manufactured by Maquet, Rastatt, Germany (Getinge, Germany), were challenged with two types of air challenges; a bolus air challenge and a gaseous microemboli challenge. The air removal characteristics of the venous bubble traps and of the complete minimally invasive extracorporeal circulation systems were assessed by measuring the gaseous microemboli volume and number downstream of the venous bubble traps in the arterial line with a bubble counter. No significant differences were observed in air reduction between the venous bubble traps of Getinge (venous bubble traps) and LivaNova (Inspire venous bubble traps 8 in conjunction with the air purge control). Similarly, no significant differences were observed in volume and number of gaseous microemboli in the arterial line of both complete minimally invasive extracorporeal circulation systems. However, the gaseous microemboli load of the Inspire Min.I system was marginally lower after both the bolus air and the gaseous microemboli challenges. Both minimally invasive extracorporeal circulation systems assessed in this study, the LivaNova Inspire Min.I and the Getinge minimized extracorporeal circulation, showed comparable air removal properties, after both bolus and gaseous microemboli air challenges. Besides, air purge control automatic air removal system provided with the LivaNova Inspire Min.I. system may enhance patient's safety with the use of a minimally invasive extracorporeal circulation system. We consider both systems equally safe for clinical use.

Quantitative Measurement and Evaluation of Red Blood Cell Aggregation in Normal Blood Based on a Modified Hanai Equation.

The aggregation of red blood cells (RBCs) in normal blood (non-coagulation) has been quantitatively measured by blood pulsatile flow based on multiple-frequency electrical impedance spectroscopy. The relaxation frequencies fc under static and flowing conditions of blood pulsatile flow are utilized to evaluate the RBC aggregation quantitatively with the consideration of blood flow factors (RBC orientation, deformation, thickness of electrical double layer (EDL)). Both porcine blood and bovine blood are investigated in experiments, for the reason that porcine blood easily forms RBC aggregates, while bovine blood does not. The results show that the relaxation frequencies fc of porcine blood and bovine blood present opposite performance, which indicates that the proposed relaxation frequency fc is efficient to measure RBCs aggregation. Furthermore, the modified Hanai equation is proposed to quantitatively calculate the influence of RBCs aggregation on relaxation frequency fc. The study confirms the feasibility of a high speed, on-line RBC aggregation sensing method in extracorporeal circulation systems.

Randomized Trial of Miniaturized Versus Standard Extracorporeal Circulation in Aortic Valve Surgery

Complications related to extracorporeal circulation remain serious. Although a minimal invasive extra corporeal circulation (MiECC) system was developed to cope with these complications, its effectivity on patient-related outcomes such as blood loss remain uncertain. Therefore, the aim of this study is to compare MiECC to an advanced standard system with respect to blood loss. A total of 128 adult patients undergoing elective isolated aortic valve replacement were enrolled in a randomized clinical trial. Patients who had undergone previous heart surgery and with preexisting kidney failure were excluded. The primary end point was postoperative blood loss after 12 hours and at drain removal. Secondary end points included intensive care and total length of stay and intubation time. At 1 hour and 12 hours after surgery, clinical laboratory data were determined. Early clinical outcomes and long-term survival were determined. MiECC patients (n= 63) had a significant lower blood loss (230 mL, 95% confidence interval: 203 to 261 mL) than regular patients (n= 62) after 12 hours (288 mL, 95% confidence interval: 241 to 344 mL, p= 0.04). A preservation of hemoglobin levels 1 hour and 12 hours after surgery in the MiECC group were observed (p < 0.001). No difference was found in early clinical outcomes and long-term survival. This randomized controlled trial compares MiECC and an advanced system for aortic valve replacement with blood loss as primary end point. We conclude that using MiECC is clinically equal for short- and long-term follow-up regarding blood loss. NTR3378.

Is blood a necessary component of the perfusate during isolated limb perfusion – a randomized controlled trial

Background: Isolated limb perfusion (ILP) is a treatment option for malignancies localized to an extremity and is performed by surgical isolation of the limb which is connected to an extracorporeal circulation system. A high concentration of a chemotherapeutic agent is perfused through the limb, while systemic toxicity is avoided. Currently, the use of packed red blood cells in the priming solution is the norm during ILP. The aim of this study was to investigate the possibility to replace an erythrocyte-based prime solution with a crystalloid-based prime solution while maintaining the regional metabolic oxygen demand during ILP.Methods: In a single-center, randomized controlled, non-blinded, non-inferiority clinical trial, 21 patients scheduled for treatment with ILP were included and randomized 1:1 to either an erythrocyte-based prime solution (control) or a crystalloid-based prime solution (intervention).Results: There was a significant difference in lactate level (mmol/L) during the perfusion between the intervention group and the control group (1.6 ± 0.4 vs. 3.6 ± 0.7, p = .001). No significant differences in oxygen extraction (%) (22 ± 11 vs. 14 ± 4, p = .06), oxygen delivery (ml/min) (90 ± 49 vs. 108 ± 38, p = .39), oxygen consumption (ml/min) (14 ± 2 vs. 14 ± 5, p = .85), regional central venous saturation (%) (83 ± 10 vs. 91 ± 4, p = .07) or INVOS (%) (76 ± 14 vs. 81 ± 11, p = .42) were found between the intervention group and the control group.Conclusion: This study showed no significant improvement with the addition of packed red blood cells into the prime solution in ensuring the metabolic oxygen demand in the treated extremity during ILP, and we, therefore, recommend that a crystalloid-based prime solution should be used.

Hemodynamic energy during pulsatile extracorporeal circulation using flexible and rigid arterial tubing: a reassessment

Pulsatile extracorporeal circulation may improve organ perfusion during cardiac surgery. Some minimally invasive extracorporeal circulation (MiECC) systems allow pulsatile perfusion. The present study investigated the influence of arterial tubing compliance on hemodynamic energy transfer into the patient. Aortic models with adult human geometry were perfused in a mock circulation. A MiECC system was connected using either high-compliance silicone tubing or standard kit tubing. Energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE) were computed from flow and pressure data. Aortic models with physiological and sub-physiological compliance were tested to assess the influence of the pseudo-patient. Non-pulsatile flow did not generate SHE. SHE during pulsatile flow in the compliant aortic model was significantly higher with kit tubing compared to silicone tubing. Maximum SHE was achieved at 1.6 L/min with kit tubing (7.7% of mean arterial pressure) and with silicone tubing (4.9%). Using the low-compliance aortic model, SHE with kit tubing reached a higher maximum of 14.2% at 1.8 L/min compared to silicone tubing (11.8% at 1.5 L/min). Flexible arterial tubing did not preserve more hemodynamic energy from a pulsatile pump compared to standard kit tubing in a model of adult extracorporeal circulation. The pseudo-patient's compliance significantly affected the properties of the mock circulation.

Clinical implementation of a novel myocardial protection pathway in coronary artery bypass surgery with minimal extracorporeal circulation.

The aim of this study was to report the clinical implementation of the joint use of the Myocardial Protection System (MPS®) and the minimal extracorporeal circulation system (MiECC), in conjunction with an institutionally refined dose/volume-dependent microplegia in coronary artery bypass grafting (CABG). Patients with isolated CABG surgery were included. The final protocol to achieve cardioplegic arrest consisted of warm blood cardioplegia with 20 mmol potassium (K), 1.6 g magnesium (Mg) and 40 mg lidocaine per liter (L) blood. We prospectively collected intra- and postoperative data to monitor and validate this novel approach. Eighty patients were operated accordingly. Mean (SD) aortic clamping time and extracorporeal perfusion time were 67.5 (22.6) and 101.1 (31.9) minutes, respectively. Failure to induce cardiac arrest was seen in six patients at the early stage of refinement of the formula. Median (IQR) high -sensitivity cardiac troponin T (hs-cTnT) on the first postoperative day (POD) and peak hs-cTnT were 262.5 ng/L (194.3-405.8) and 265.5 ng/L (194.3-405.8), respectively. Median (IQR) creatine kinase-myocardial type (CK-MB) on POD 1 and peak CK-MB were 14.2 µg/L (10.5-22.7) and 14.2 µg/L (10.7-23.2), respectively. Median (IQR) creatine kinase (CK) on POD 1 and peak CK were 517.5 U/L (389.3-849.8) and 597.5 U/L (455.0-943.0), respectively. No patient died during hospitalization. The combination of this cardioplegic formula with MPS® and MiECC in CABG was safe and feasible. With the final chemical makeup, cardiac arrest was reliably achieved. Remarkably low postoperative cardiac markers indicate shielded cardiac protection during surgery.

Q-PULS, a new quasi-physiological pulsatile extracorporeal model to simulate heart function.

The invention of new surgical procedures requires testing at different stages including animal models. To facilitate this process, we have developed a computer-controlled extracorporeal circulation system for testing of an explanted porcine heart simulating a variety of physiological parameters. Mitral valve function can be assessed before and after induced valve insufficiency and after valve repair. Accordingly, techniques and instruments can be modified at early stages of prototype development. In the diastole, the left atrium is passively filled through the reservoir. The loading pressure of the atrium and flow rates can be widely adjusted. To simulate the systole, a linear motor-driven piston pump promotes volume into the left ventricle and the aorta. An additional circulatory pump compensates for undesired total emptying of the heart chambers. The processor control of the linear pump allows for various settings of flow rate, velocity and even irregular rhythm. Twenty-one isolated porcine hearts were used. The leaflet movement was filmed using a universal serial bus (USB)-probe camera. With 80 mm stroke and 1 m/s speed, a volume of 150 ml can be pumped at a heart rate of up to 73 bpm. Cardiac outputs of up to 10.9 l/min can be achieved. Constant visualization and continuous measurements of the pressure gradients before and after the induction of mitral insufficiency and after repair allowed quantitative verification of repair quality under beating-heart conditions. This model allows a controllable pulsation, loading and unloading of a porcine heart in a wide range. Thus, the function of the leaflets and repair results can be qualitatively and quantitatively evaluated under quasiphysiological conditions.

OC06 BUILDING UP A MULTIDISCIPLINARY 360° MINIMALLY INVASIVE PROGRAM FOR AVR: OUR EXPERIENCE

Aim: The aim of this study was to report the first results of our multidisciplinary minimally invasive program to treat patients who require aortic valve replacement (AVR), which involves: 1) reduced chest incision (through upper ministernotomy or right anterior minithoracotomy), 2) sutureless or rapid deployment AVR, 3) minimally invasive extracorporeal circulation (MiECC) system and 4) ultra fast-track (UFT) anaesthesia. Methods: Data from 167 consecutive patients undergoing primary isolated aortic valve replacement through minimally invasive approaches (MIAVR) between October 2016 and April 2018 were prospectively collected. The mean age of the study population was 74 ± 9 years, and the average EuroSCORE II was 2.1 ± 1.2. Results: MIAVR was performed using sutureless or rapid deployment valves in 76 (45.5%) patients, MiECC system in 63 (37.7%), and UFT management in 67 (40.1%). Overall in-hospital mortality was 0.6% (n = 1). The rate of postoperative stroke and atrioventricular block requiring pacemaker implantation was 1.2% (n = 2) and 3.6% (n = 6), respectively. MiECC system was associated with reduced postoperative bleeding (requiring chest re-opening) compared with conventional cardio-pulmonary bypass circuits (0% vs. 5.8%, p = 0.05). The mean intensive care unit stay was 25 hours in UFT patients and 52.2 hours in no-UFT patients (p = 0.04). Hospital stay was similar between groups (UFT 6.9 days, no-UFT 13.9 days, p = 0.2). Conclusions: Our UFT mini AVR program is a multidisciplinary minimally approach that involves the latest best technologies and techniques for AVR. We believe it may considerably increase patient's comfort being associated with faster recovery and excellent hospital outcomes.

Prospective, Randomized Un-Blinded Three Arm Controlled Study in Coronary Artery Revascularization with Minimal Invasive Extracorporeal Circulation Systems (MiECC): Surrogate Parameter Analysis of Biocompatibility.

Minimal extracorporeal circulation techniques and systems (MiECC) may reduce the negative side effects of conventional extracorporeal circulation (ECC). However, it is still unclear as to what this is caused by, the reduced priming volume and hemodilution, or the avoidance of blood-air contact and dispersion of mediastinal debris into the systemic circulation. The aim of the trial was the comparison of MiECC to an open ECC setup (openECC) or a system with reduced blood air and debris interaction (closeECC).Methods: In a prospective randomized trial, 72 patients (73 ± 5.3 years; 83% male) referred for coronary artery bypass graft (CABG) were randomly assigned either to MiECC (priming volume 550mL), closeECC, or openECC (priming volume 1250mL). The laboratory surrogate endpoints (renal function, inflammatory response, ischemia, coagulation, and hemolysis) and clinical data were measured at six different time points (T1-6).Results: Patients were comparable for all preoperative variables. The operation times (MiECC 261 ± 79min; openECC 264 ± 75min; closeECC 231 ± 68min) and perfusion times (MiECC 115 ± 49min; openECC353 107 ± 37min; closeECC 99 ± 22min) revealed a trend of faster performance in the closeECC group (P < .05). Pro-inflammatory cytokines, ischemia, and coagulation markers were significantly elevated postoperatively in all cardiopulmonary bypass types, and decreased to pre-baseline levels at discharge (T5) without identifiable statistical differences between the three study groups. Free-hemoglobin was not significantly increased by centrifugal pump or cell saver procedures. Significant intraoperative hemodilution effects due to the different priming volumes were demonstrated only at the end of operation (T2) (MiECC Hb 9.6 ± 1.1g/dL; openECC Hb 9.0 ± 0.8g/dL; closeECC Hb 8.7 ± 1g/dL; P =. 01). Neither the hemodilution, suction technique (MiECC), nor blood-air interface (closeECC) could show sustainable benefits in this underpowered study, compared to conventional ECC systems (openECC) in a high volume series of surrogate parameters.

Suction towards a vessel wall by hemodialysis catheters\u2014the establishment of a new experimental extracorporeal circulation system using pig veins

BackgroundHemodialysis catheters are commonly used for vascular access in patients undergoing blood purification therapies. However, the sudden dysfunction of catheters represents a serious problem, and while we know that the major causative factor is suction between the catheter and the vessel wall, it is very difficult to evaluate this in vivo. Therefore, we created a new experimental system to investigate this phenomenon ex vivo, using pig veins, which allowed us to quantitatively analyze the effect of suction.MethodsWe attempted to create a model system for quantitative evaluation using azygos veins from a pig. Four types of catheters were inserted into an extracted pig vein: true circle type 1, true circle type 2, semi-circle type 1, and semi-circle type 2. We then circulated 50% glycerol solution through the vein at a flow rate (Qv) from 100 to 1000 mL/min. Glycerol solution was also circulated within the catheters at a flow rate (Qb) from 100 to 200 mL/min. We measured the frequency of suction towards the vessel wall ten times, under each experimental schedule, at a Qb of both 100 and 200 mL/min. We then measured the pressure between the pre-Qb pump and the blood circuit, when the arterial side opening was positioned approximately in the center of the blood vessel to prevent catheter suction towards the vessel wall.ResultsSuction towards the vessel wall occurred 8/10 times with the true circle type 1 catheter and 10/10 times with the semi-circle type 2 catheter in the arterial pore of the catheter is only one, when Qb and Qv were 100 and 100 mL/min, respectively. Suction towards the vessel wall occurred 3/10 times with the semi-circle type 2 catheter, when Qb and Qv were 100 and 1000 mL/min, respectively. The true circle type 1 catheter showed a minimum pressure of − 58.6 ± 0.516 mmHg when Qb and Qv were 100 and 300 mL/min, respectively, while the true circle type 2 catheter showed a minimum pressure of − 137 ± 5.96 mmHg when Qb and Qv were 200 and 300 mL/min, respectively.ConclusionsWe successfully established a novel ex vivo evaluation system for catheters using a pig vein which allowed us to recreate the effect of suction from catheters towards a vessel wall in vivo.

Ultra fast track surgery: a rapid deployment aortic valve replacement through a J-ministernotomy.

Aortic valve surgery has been undergone continuous development over the last years, involving less invasive techniques and the use of new technologies to reduce the traumatic impact of the intervention and extend the operability toward increasingly high-risk patients. Minimally invasive aortic valve replacement (AVR) has gradually been recognized as a less traumatic technique compared to median sternotomy, becoming first choice approach in numerous experienced centers. Herein we present our multidisciplinary minimally invasive approach for AVR, involving: (I) reduced chest incision; (II) rapid deployment AVR; (III) minimally invasive extracorporeal circulation system; and (IV) ultra fast track (UFT) anaesthetic management.

Ultra fast-track minimally invasive aortic valve replacement: going beyond reduced incisions.

Aortic valve replacement (AVR) via a median sternotomy approach has been largely reported to be safe and long-term efficacious, and currently represents the 'gold standard' approach for aortic stenosis treatment. However, aortic valve surgery has undergone continuous development over the last years, involving less invasive techniques and new technologies to reduce the traumatic impact of the intervention and extend the operability toward increasingly high-risk patients. Indeed, minimally invasive AVR and transcatheter aortic valve replacement caseload have steadily increased leading to a paradigm shift in the treatment of aortic valve disease. In this setting, we have established a multidisciplinary minimally invasive programme to treat patients who require AVR. Herein, we present our approach including (i) reduced chest incision (through a J ministernotomy), aiming to reduce the traumatic impact of the surgical procedure, to decrease blood loss, postoperative pain and wound complications and to increase patient's satisfaction; (ii) rapid-deployment AVR, to reduce operative times, to facilitate minimally invasive approach and to improve haemodynamic outcomes; (iii) minimal invasive extracorporeal circulation system, to improve end-organ protection, to decrease systemic inflammatory response and to promote fast-track anaesthesia and (iv) ultra fast-track anaesthesia, to decrease the rate of postoperative complications and assure better and earlier recovery.

Red blood cells aggregability measurement of coagulating blood in extracorporeal circulation system with multiple-frequency electrical impedance spectroscopy

Red blood cells (RBCs) aggregability AG of coagulating blood in extracorporeal circulation system has been investigated under the condition of pulsatile flow. Relaxation frequency fc from the multiple-frequency electrical impedance spectroscopy is utilized to obtain RBCs aggregability AG. Compared with other methods, the proposed multiple-frequency electrical impedance method is much easier to obtain non-invasive measurement with high speed and good penetrability performance in biology tissues. Experimental results show that, RBCs aggregability AG in coagulating blood falls down with the thrombus formation while that in non-coagulation blood almost keeps the same value, which has a great agreement with the activated clotting time (ACT) fibrinogen concertation (Fbg) tests. Modified Hanai formula is proposed to quantitatively analyze the influence of RBCs aggregation on multiple-frequency electrical impedance measurement. The reduction of RBCs aggregability AG is associated with blood coagulation reaction, which indicates the feasibility of the high speed, compact and cheap on-line thrombus measurement biosensors in extracorporeal circulation systems.

Q-PULS: A New Quasi-Physiological Pulsatile Extracorporeal Model to Simulate Heart Function Substituting Animal Experiments

Background: Inventing new surgical procedures is demanding. A computer-controlled extracorporeal circulation system allows for testing of an explanted porcine heart simulating a variety of physiological and functional parameters. Mitral valve function can be assessed before and after induced valve insufficiency and after valve repair. Accordingly, technique and instruments can be modified in the early stages of prototype development.

Is 300 Seconds ACT Safe and Efficient during MiECC Procedures?

The recommended minimum activated clotting time (ACT) level for cardiopulmonary bypass (CPB) of 480 seconds originated from investigations with bubble oxygenators and uncoated extracorporeal circulation (ECC) systems. Modern minimal invasive ECC (MiECC) systems are completely closed circuits containing a membrane oxygenator and a tip-to-tip surface coating. We hypothesized that surface coating and the "closed-loop" design allow the MiECC to safely run with lower ACT levels and that an ACT level of 300 seconds can be safely applied without thromboembolic complications. The aim of this study was to investigate the potential risks during application of reduced heparin levels in patients undergoing coronary surgery. In this study, 68 patients undergoing coronary artery bypass grafting with MiECC were randomized to either the study group with an ACT target of 300 seconds or the control group with an ACT of 450 seconds. All other factors of MiECC remained unchanged. The study group received significantly less heparin and protamine (heparin [international units] median [min-max], Red_AC: 32,800 [23,000-51,500] vs. Full_AC: 50,000 [35,000-65,000] p < 0.001; protamine [international units], Red_AC: 18,000 [10,000-35,000] vs. Full_AC: 30,000 [20,000-45,000] p < 0.001). The ACT in the study group was significantly lower at the start of MiECC (mean ± standard deviation: study group 400 ± 112 vs. control group 633 ± 177; p < 0.0001). Before termination of CPB the ACT levels were: study group 344 ± 60 versus control group 506 ± 80. In both groups, the values of the endogenous thrombin potential (ETP) decreased simultaneously. None of the study participants experienced thromboembolic complications. Since no evidence of increased thrombin formation (ETP) was found from a laboratory standpoint, we concluded that the use of MiECC with a reduced anticoagulation strategy seems possible. This alternative anticoagulation strategy leads to significant reduction in dosages of both heparin and protamine. We can confidently move forward with investigating this anticoagulation concept. However, to establish clinical safety of ACT below 300 seconds, we need larger clinical studies.

Shed-blood-separation and cell-saver: an integral Part of MiECC? Shed-blood-separation and its influence on the perioperative inflammatory response during coronary revascularization with minimal invasive extracorporeal circulation systems - a randomized controlled trial.

The postoperative systemic inflammatory response after cardiopulmonary bypass (CPB) is still an undesirable side-effect after cardiac surgery. It is most likely caused by blood contact with foreign surfaces and by the surgical trauma itself. However, the recirculation of activated shed mediastinal blood is another main cause of blood cell activation and cytokine release. Minimal invasive extracorporeal circulation (MiECC) comprises a completely closed circuit, coated surfaces and the separation of suction blood. We hypothesized that MiECC, with separated cell saved blood, would induce less of a systemic inflammatory response than MiECC with no cell-saver. The aim of this study was, therefore, to investigate the impact of cell washing shed blood from the operating field versus direct return to the ECC on the biomarkers for systemic inflammation. In the study, patients with MiECC and cell-saver were compared with the control group, patients with MiECC and direct re-transfusion of the drawn blood shed from the surgical field. High amounts of TNF-α (+ 120% compared to serum blood) were found in the shed blood itself, but a significant reduction was demonstrated with the use of a cell-saver (TNF-α ng/l post-ECC 10 min: 9.5±3.5 vs. 19.7±14.5, p<0.0001). The values for procalcitonin were not significantly increased in the control group (6h: 1.07±3.4 vs. 2.15±9.55, p=0.19) and lower for C-reactive protein (CRP) (24h: 147.1±64.0 vs.134.4±52.4 p=0.28). The use of a cell-saver and the processing of shed blood as an integral part of MiECC significantly reduces the systemic cytokine load. We, therefore, recommend the integration of cell-saving devices in MiECC to reduce the perioperative inflammatory response.

Use of vasopressors and inotropics in cardiogenic shock

Vasoactive drugs and inotropic agents are important for the hemodynamic management of cardiogenic shock. In this article the use of different vasoactive and ionotropic drugs in cardiogenic shock is presented. Hemodynamic management during cardiogenic shock occurs after initial moderate volume delivery by dobutamine to increase inotropism. If adequate perfusion pressures are not achieved norepinephrine is administered. If asufficient increase in cardiac performance can still not be achieved by the treatment, administration of levosimendan or phosphodiesterase (PDE) inhibitors may be necessary. Levosimendan is superior to PDE inhibitors for patients in cardiogenic shock. The aim of hemodynamic management in cardiogenic shock is to allow the transient use of inotropics and vasopressors in the lowest necessary dose and only as long as necessary. The daily question is whether the dose can be reduced or in the case of deterioration whether the use of an extracorporeal circulatory support system should be considered. There are currently no available data on mortality that demonstrate the benefit of hemodynamic monitoring using target criteria. The advantage, however, results from the economic use of inotropics and vasopressors by certain target criteria.

Cerebral microembolic load in open heart surgery with different extracorporeal circulation systems

Somanetics 5100C was used to assess regional tissue oxygen saturation. DO2 and VO2 values to assess the oxygen delivery and consumption were also calculated. The association between cerebral and somatic rSO2 trends and mean arterial pressure, pump flow and blood gases were also studied. Results. it was found that prolonged episodes of decrease of somatic rSO2 during cardiopulmonary bypass with lower haemoglobin levels and DO2 values were strongly associated with occurrence of post-op organ disorders especially acute kidney injury. As the results of the correspondence analysis it was shown that for positive outcome without organ disorders greater importance have absolute values of DO2, VO2 and rSO2 (both cerebral and somatic), but for the poor outcome with complications the length of episodes of rSO2 decrease has the greater influence. It was also found that somatic rSO2 values are not strongly associated with pump flow or mean arterial pressure or arterial pO2. Discussion. the use of continuous monitoring of cerebral and even somatic rSO2 during cardiopulmonary bypass in adults may help the prefusionist to assess the adequacy of tissue oxygenation. To improve the somatic and cerebral rSO2 complex strategy is needed to be worked out because the routine increase of pump or gas flow was shown to be not enough and sometimes controversial [2].

Development of an Accident Reproduction Simulator System Using a Hemodialysis Extracorporeal Circulation System

Background:Accidents that occur during dialysis treatment are notified to the medical staff via alarms raised by the dialysis apparatus. Similar to such real accidents, apparatus activation or accidents can be reproduced by simulating a treatment situation. An alarm that corresponds to such accidents can be utilized in the simulation model.Objectives:The aim of this study was to create an extracorporeal circulation system (hereinafter, the circulation system) for dialysis machines so that it sets off five types of alarms for: 1) decreased arterial pressure, 2) increased arterial pressure, 3) decreased venous pressure, 4) increased venous pressure, and 5) blood leakage, according to the five types of accidents chosen based on their frequency of occurrence and the degree of severity.Materials and Methods:In order to verify the alarm from the dialysis apparatus connected to the circulation system and the accident corresponding to it, an evaluation of the alarm for its reproducibility of an accident was performed under normal treatment circumstances. The method involved testing whether the dialysis apparatus raised the desired alarm from the moment of control of the circulation system, and measuring the time it took until the desired alarm was activated. This was tested on five main models from four dialyzer manufacturers that are currently used in Japan.Results:The results of the tests demonstrated successful activation of the alarms by the dialysis apparatus, which were appropriate for each of the five types of accidents. The time between the control of the circulatory system to the alarm signal was as follows, 1) venous pressure lower limit alarm: 7 seconds; 2) venous pressure lower limit: 8 seconds; 3) venous pressure upper limit: 7 seconds; 4) venous pressure lower limit alarm: 2 seconds; and 5) blood leakage alarm: 19 seconds. All alarms were set off in under 20 seconds.Conclusions:Thus, we can conclude that a simulator system using an extracorporeal circulation system can be set to different models of dialyzers, and that the reproduced treatment scenarios can be used for simulation training.

Use of minimal invasive extracorporeal circulation in cardiac surgery: principles, definitions and potential benefits. A position paper from the Minimal invasive Extra-Corporeal Technologies international Society (MiECTiS).

Minimal invasive extracorporeal circulation (MiECC) systems have initiated important efforts within science and technology to further improve the biocompatibility of cardiopulmonary bypass components to minimize the adverse effects and improve end-organ protection. The Minimal invasive Extra-Corporeal Technologies international Society was founded to create an international forum for the exchange of ideas on clinical application and research of minimal invasive extracorporeal circulation technology. The present work is a consensus document developed to standardize the terminology and the definition of minimal invasive extracorporeal circulation technology as well as to provide recommendations for the clinical practice. The goal of this manuscript is to promote the use of MiECC systems into clinical practice as a multidisciplinary strategy involving cardiac surgeons, anaesthesiologists and perfusionists.