3D-Printed silicone anatomic patient simulator to enhance training on cardiopulmonary bypass.

BACKGROUND: Simulator training is important for teaching perfusion students fundamental skills associated with CBP before they start working in the clinic. Currently available high-fidelity simulators lack anatomic features that would help students visually understand the connection between hemodynamic parameters and anatomic structure. Therefore, a 3D-printed silicone cardiovascular system was developed at our institution. This study aimed to determine whether using this anatomic perfusion simulator instead of a traditional "bucket" simulator would better improve perfusion students' understanding of cannulation sites, blood flow, and anatomy. METHODS: Sixteen students were tested to establish their baseline knowledge. They were randomly divided into two groups to witness a simulated bypass pump run on one of two simulators - anatomic or bucket - then retested. To better analyze the data, we defined "true learning" as characterized by an incorrect answer on the pre-simulation assessment being corrected on the post-simulation assessment. RESULTS: The group that witnessed the simulated pump run on the anatomic simulator showed a larger increase in mean test score, more instances of true learning, and a larger gain in the acuity confidence interval. CONCLUSIONS: Despite the small sample size, the results suggest that the anatomic simulator is a valuable instrument for teaching new perfusion students.

A review of antiplatelet drugs, coronary artery diseases and cardiopulmonary bypass.

UNLABELLED: Platelets play a major role in the thromboembolic diseases and upon vascular injury, especially arterial vascular injury. These platelets rapidly adhere to the exposed subendothelial area, where they become activated by contacting with stimulants. Antiplatelet therapy remains extremely important in treatment and prophylaxis of arterial thromboembolic disorders such as coronary arterial diseases and stroke. The antiplatelet drugs (APDs) are among the most widely used in the world. Based on the molecular targets, APDs are classified as Thromboxane A2 pathway blockers, ADP receptor antagonists, GPIIa/IIIb antagonists, adenosine reuptake inhibitors, phosphodiesterase inhibitors, thrombin receptor inhibitors, and others. Coronary artery bypass graft (CABG) surgery is an important therapeutic approach to treat coronary artery disease. Long-term success after CABG depends on the patency of the bypass vessels. Since platelets play a crucial role in the pathogenesis of thrombosis in the blood vessels, APDs are broadly used to reduce serious cardiovascular events. Platelets also are an integral part of inflammation and APDs have demonstrated to reduce the inflammation mediators in the healthy volunteers and coronary artery disease patients; it will be an interesting topic to determine if platelet inhibition will attenuate CPB-induced systemic inflammatory response syndrome. Due to concerns of post-op bleeding with use of APDs, it is a common practice to withhold APDs prior to surgery; however, recent studies have demonstrated that continuation of APDs prior to surgery (even until the day of surgery) does not increase the risk of post-op bleeding. With extensive use of APDs in cardiovascular thromboembolic events, APD resistance becomes problematic in clinical antiplatelet therapy. Since there is no standardized or universal definition available to quantify APDs resistance, a clinically meaningful definition of APD resistance needs to be developed based on data linking laboratory tests to clinical outcomes in patients. KEYWORDS: antiplatelet drug, coronary artery diseases, cardiopulmonary bypass, clinical trials, drug resistance, platelet mapping.

Systemic inflammatory response during cardiopulmonary bypass and strategies.

Organ dysfunction after cardiopulmonary bypass (CPB) still is a major problem in patients undergoing cardiovascular surgery. Studies have demonstrated that systemic inflammatory response (SIR) remains one of the major causes of CPB-associated organ injury. The mechanism of SIR during CPB includes the interaction of blood and artificial surface and endotoxemia. The interaction of blood and artificial surface is initiated by protein adsorption. As a result of series of chain reactions, the numerous powerful inflammatory mediators, including hormones and autacoids, are formed and released. Subsequently, the contact system, coagulation system, complement system, fibrinolysis system, and leukocytes, platelets, and endothelial cells, are all activated to participate in the interaction of blood and artificial materials. These activations of different systems and blood cells can interact and magnify each other. CPB-associated endotoxemia has been demonstrated to intensify and deteriorate SIR during CPB. SIR leads to organ injury. In clinical setting, the most common SIR-related organ damage is pulmonary dysfunction, which often is manifested by decreasing of lung compliance, rise in shunt fraction, work of breathing, and likelihood of atelectasis and pneumonia. Strategies to control CPB-related SIR have been developed, such as improvement of biocompatibility of artificial surface (new biomaterials), temporary inhibition of blood cells activation ("blood anesthesia") during CPB, and blockage of the bioactivities and effects of inflammatory mediators.

Combination of acute preoperative plateletpheresis, cell salvage, and aprotinin minimizes blood loss and requirement during cardiac surgery.

Acute preoperative plateletpheresis (APP), cell salvage (CS) technique, and the use of aprotinin have been individually reported to be effective in reducing blood loss and blood component transfusion while improving hematological profiles in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). In this prospective randomized clinical study, the efficacy of these combined approaches on reducing blood loss and transfusion requirements was evaluated. Seventy patients undergoing primary coronary artery bypass grafting (CABG) were randomly divided into four groups: a control group (group I, n = 10) did not receive any of the previously mentioned approaches. An APP and CS group (group II, n = 20) experienced APP in which preoperative platelet-rich plasma was collected and reinfused after reversal of heparin, along with the cell salvage technique throughout surgery. The third group (group III, n = 22) received aprotinin in which 5,000,000 KIU Trasylol was applied during surgery, and a combination group (group IV, n = 18) was treated with all three approaches, i.e., APP, CS, and aprotinin. Compared with group I (896+/-278 mL), the postoperative total blood loss was significantly reduced in groups II, III, and IV (468+/-136, 388+/-122, 202+/-81 mL, respectively, p < 0.05). The requirements of packed red blood cells in the three approached groups (153+/-63, 105+/-178, 0+/-0 mL, respectively) also were reduced when compared with group I (343+/-118 mL, p < 0.05). In group I, six patients (6/10) received fresh-frozen plasma and three patients (3/10) received platelet transfusion, whereas no patients in the other three groups required fresh-frozen plasma and platelet. In conclusion, both plateletpheresis concomitant with cell salvage and aprotinin contribute to the improvement of postoperative hemostasis, and the combination of these two approaches could minimize postoperative blood loss and requirement.

Low serum sodium level during cardiopulmonary bypass predicts increased risk of postoperative stroke after coronary artery bypass graft surgery.

OBJECTIVE: Rapid decreases in serum sodium levels are associated with altered mental status, seizures, and coma. During cardiac surgery, serum sodium levels decrease rapidly when cardiopulmonary bypass is initiated because cardiopulmonary bypass causes hemodilution. However, whether this decrease influences neurologic outcome after cardiac surgery remains unclear. We investigated whether the average serum sodium level during cardiopulmonary bypass is independently predictive of postoperative stroke or 30-day all-cause mortality in patients who undergo primary coronary artery bypass grafting. METHODS: In a single-institution, retrospective cohort of 2348 consecutive patients who underwent primary, isolated coronary artery bypass grafting, sequential multivariate logistic regression was performed to determine the threshold below which the average serum sodium level during cardiopulmonary bypass independently predicts postoperative stroke or early death. To further test the validity of this threshold and to control for selection bias, stepwise multivariate logistic regression was also performed on propensity score-matched patients (n = 924). RESULTS: An average serum sodium level less than 130 mEq/L during cardiopulmonary bypass was independently predictive of stroke, both in the entire study cohort (1.44% vs 2.92%; odds ratio, 2.09; 95% confidence interval, 1.1-4.1; P = .03) and in the propensity-matched patients (0.9% vs 3.0%; odds ratio, 4.1; 95% confidence interval, 1.3-13.0; P = .02). The average serum sodium level during cardiopulmonary bypass was not independently associated with early death, regardless of what threshold value was used. CONCLUSIONS: An average serum sodium level of less than 130 mEq/L during cardiopulmonary bypass is independently associated with an increased risk of postoperative stroke in patients who undergo primary coronary artery bypass grafting.

Extracorporeal membrane oxygenation with hemoconcentration: in a hypervolemic patient with critical aortic stenosis.

Herein, we describe the case of a 60-year-old man with severe nonischemic cardiomyopathy and hypervolemia. By means of venoarterial extracorporeal membrane oxygenation at the bedside, along with hemoconcentration, the patient was resuscitated from severe cardiogenic shock and normal blood volume was restored. Within 24 hours, he was able to undergo a high-risk aortic valve replacement for severe aortic stenosis, with a successful outcome. To our knowledge, this is the first reported case in which hemoconcentration with extracorporeal membrane oxygenation has been used to support a patient with severe hypervolemia.