2021 MiECTiS focused update on the 2016 position paper for the use of minimal invasive extracorporeal circulation in cardiac surgery.

The landmark 2016 Minimal Invasive Extracorporeal Technologies International Society (MiECTiS) position paper promoted the creation of a common language between cardiac surgeons, anesthesiologists and perfusionists which led to the development of a stable framework that paved the way for the advancement of minimal invasive perfusion and related technologies. The current expert consensus document offers an update in areas for which new evidence has emerged. In the light of published literature, modular minimal invasive extracorporeal circulation (MiECC) has been established as a safe and effective perfusion technique that increases biocompatibility and ultimately ensures perfusion safety in all adult cardiac surgical procedures, including re-operations, aortic arch and emergency surgery. Moreover, it was recognized that incorporation of MiECC strategies advances minimal invasive cardiac surgery (MICS) by combining reduced surgical trauma with minimal physiologic derangements. Minimal Invasive Extracorporeal Technologies International Society considers MiECC as a physiologically-based multidisciplinary strategy for performing cardiac surgery that is associated with significant evidence-based clinical benefit that has accrued over the years. Widespread adoption of this technology is thus strongly advocated to obtain additional healthcare benefit while advancing patient care.

Comparison of a perfusion simulator to a clinical operating room: evaluation of eye tracking data and subjective perception. A pilot study.

BACKGROUND: With the aim of evaluating the perfusion simulator at the German Heart Center Berlin, similarity between simulation and clinical operation room (OR) was investigated regarding subjective perception and eye movement. METHODS: Eight perfusionists performed an operation on the heart-lung machine (HLM) wearing eye tracking glasses, each in real OR and simulator. The three most important phases for perfusionists (going on bypass, cardioplegia administration and coming off bypass) were considered. Additional to eye tracking data as objective measure, questionnaires were completed, and interviews conducted afterwards. RESULTS: The structure of simulator and real OR is perceived as basically the same. Yet there are differences in the HLM-models used and the temporal sequence. Different perception of both situations is reported in interviews and reflected in significant differences in the rating scales (NASA-TLX) on three of six subscales. In eye tracking data, certain AOIs could be identified for the individual phases, both in OR and simulator-an indication of fundamental similarity. However, differences regarding the proportions of the individual AOIs, especially in the first and third phase, are leading to the assumption that the simulator, and especially the simulation process, is only valid to a limited extent regarding subjective perception and eye tracking data. CONCLUSION: The use of the simulator for (advanced) training is accepted and explicitly requested by perfusionists. Yet further research is needed to identify the decisive factors (like simulation duration or additional tasks) for a valid execution in the simulator. Furthermore, a larger sample size should be regarded to allow statistical analysis.

Technical implementation of percutaneous thrombus aspiration using the AngioVac system.

OBJECTIVES: The AngioVac system (AngioDynamics, Latham, NY, USA) provides a method for the minimally invasive, percutaneous aspiration of thrombus formations originating from the central venous system as well as solid matter such as lead vegetations and right atrial thrombi. METHODS: This retrospective, observational study describes the initial experience in 52 adult patients with the AngioVac system, focusing mainly on the development of the extracorporeal circuit to improve usability and safety. RESULTS: The mean patient age was 62.9 years (range 23-86 years). 22 patients were female and 30 were male. Indications for percutaneous aspiration were lead vegetations (n = 36; 69.2%), right atrial thrombi (n = 9; 17.3%), central venous thrombi (n = 5; 9.6%) and pulmonary embolisms (n = 2; 3.8%). Successful aspiration was performed in 44 cases (84.6%) and partial success was achieved in five patients (9.6%), while failure to remove thrombi or vegetations occurred in three cases (5.8%). Our practical experience led to the installation of a shunt line for recirculation and the implementation of safety features concerning air handling, which are also employed in minimally invasive extracorporeal bypass circuits. Initial tests monitored the level of negative pressure according to differences in flow and access sites but these still have to be validated on a larger scale. CONCLUSION: In this initial experience, the AngioVac system appeared to be safe regarding the extracorporeal circulation and the elimination of thrombi and lead vegetations.

Simulation-based training of critical events during cardiopulmonary bypass: importance of a critical events checklist.

OBJECTIVES: Evaluation of critical events training for clinical perfusionists is necessary to improve this educational approach. Critical events checklists are effective in reducing clinical complications, but should be tested in a simulation environment first. Individual behavior and stress response of clinical perfusionists during simulated critical events on cardiopulmonary bypass have not been evaluated yet. This study focuses on the evaluation of critical events training and critical events checklists in simulated cardiopulmonary bypass. METHODS: A total of 19 clinical perfusionists from a single hospital took part in two simulated critical event scenarios. Clinical perfusionist behavior and physiological responses were recorded using eye tracking, heart rate variability, video, and audio. In addition, workloads were determined and participants were interviewed. RESULTS: Relevant areas of interest were identified for each simulation phase. During critical event detection and subsequent decision-making, areas of interest hits and fixation durations varied with the use of a critical events checklist. Times to decision were shorter, decision quality was higher, and temporal workload was increased when the checklist was used. Evaluation of selected heart rate variability measures revealed a good correlation with pupil diameters. CONCLUSION: Evaluation of critical events during simulated cardiopulmonary bypass shows that the scenario is realistic and relevant for clinical practice. Integrating a critical events checklist improves the probability of correct decision-making and shortens the correct decision time. Temporal workload is increased when using a checklist. Eye tracking and heart rate variability are well suited to evaluate participants' behaviors and stress levels. All participants welcomed simulation training for critical incidents.

Simulation in perfusion: evaluating the efficacy of a specific training with eye-tracking.

BACKGROUND: With the aim of integrating simulation training into the training of perfusionists, we examined whether the participants were able to transfer a specific learning content to the same and different situations and assessed their feedback on the simulation training. Eye-tracking was tested as a measure and supplemented by additional measures. METHODS: A 2 × 2 mixed design was used, with test time (pre- and post-test) and training group (same and different content training) as factors. In the pre- and post-test, the participant had to handle a critical situation on the cardiopulmonary bypass, namely, a drop in arterial partial oxygen pressure. Between the two test times, the participant practised under guidance the handling of either the same critical situation (Group 1) or a different one, that is, impaired venous return (Group 2). Dependent measures were fixations of the eyes on specific areas of interest on the heart-lung machine, measures of latency and subjective assessments. Moreover, participants gave feedback on the simulation training. RESULTS: Fixation analyses showed that the training led to an increased gaze on areas of interest relevant to the drop in arterial partial oxygen pressure in both groups, with a significant increase only for Group 1. The surveys revealed a great interest in the integration of simulation training into education. CONCLUSION: In combination with other measures, eye-tracking is suitable for the evaluation of simulation training. Due to the positive training effects and positive participant feedback, the integration of simulation into the training of perfusionists is advocated. Concerning transfer of learning content, more research is needed.

Evaluation of attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiac operations: a pilot study.

BACKGROUND: Performing cardiopulmonary bypass is a complex task which involves evaluating visual input from patient monitors and technical parameters displayed at the heart-lung machine console as well as reacting to other sensory input. Only few studies are available concerning the competency requirements for clinical cardiovascular perfusionists, including attention, perception, and coping with mental stress. This study aims at evaluating attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiopulmonary bypass. METHODS: Nine clinical cardiovascular perfusionists voluntarily offered to participate in the study. Participants were asked to wear Tobii 2 eye-tracking glasses throughout the procedures. Specific time points were analyzed (cardiopulmonary bypass on, initial cardioplegia delivery, steady state, cross-clamp off, and weaning from cardiopulmonary bypass). Data acquisition was supplemented by participants' self-evaluation regarding their stress levels and by National Aeronautics and Space Administration Task Load Index (NASA TLX) questionnaires. RESULTS: Seven datasets were sufficient to be evaluated. The clinical cardiovascular perfusionists' professional experience ranged from 0.5 to 24 years. Evaluation of eye-tracking data revealed large variations in areas of interest hits, fixation, and dwell times. Across all phases, the venous reservoir, mean arterial pressure, arterial pump display, cardioplegia control, and data management system received the highest levels of attention. Pupil diameter measurements increased at start of cardiopulmonary bypass, cardioplegia delivery, and weaning off, but returned to base level during steady state. Clinical cardiovascular perfusionists' self-evaluation showed that subjective stress level was highest at the start and the end of the procedure. NASA TLX questionnaires revealed medium-to-high mental and temporal workloads, but low physical workloads. Performance, effort, and frustration indices showed medium workloads. CONCLUSION: During cardiopulmonary bypass, perfusionists are subjected to stress. Peak stress levels were highest during start and end of cardiopulmonary bypass. Furthermore, visual attention and perception varied between the operative phases. Further studies are indicated to evaluate the design of heart-lung machines and stress-coping strategies during cardiopulmonary bypass.

Position article for the use of extracorporeal life support in adult patients.

Extracorporeal life support (ECLS) is one of the recent fields in cardiac surgery which has improved significantly the quality of patient care in acute or chronic end-stage heart disease. The safe use of this new technology requires many different prerequisites which are summarized in this position article. It includes the necessary personnel and their qualifications, the structural assumptions, the required equipment, and the parameters which have to be monitored for the safe usage of these devices. In addition, indications and contraindications for ECLS, the management and control of a wide range of parameters related to the extracorporeal circulation, as well as the necessary equipment are described. Quality assurance and education are also described in this position article.

Which competencies are necessary for clinical perfusion in Germany? Interviews with perfusionists.

BACKGROUND: The professional education of cardiovascular perfusionists in Germany and the expertise required for successful practice have not often been studied. Here, the necessary skills for clinical cardiovascular perfusion-ists are described. METHOD: The prerequisites for the practice of the profession, expected future developments and the question of the positioning of a future professional perfusionist training within the educational system were discussed with ten experienced perfusionists. These individuals were interviewed in a semi-standardized fashion following an interview manual and the interviews were evaluated using qualitative research methods. RESULTS: The professional skills currently required of per-fusionists correspond to the list of activities published by the German Society of Cardiovascular Enginering. New areas are knowledge of management and, increasingly, social competence and self-management skills. Future tasks for perfusionists will be more diversified than at present. CONCLUSION: Training for perfusionists should be made broader than it is today. The current restructuring taking place in the profession makes interdisciplinary orientation and increased emphasis on practical training necessary. Academic level education is both feasible and desirable.

Improvement in survival after mechanical circulatory support with pneumatic pulsatile ventricular assist devices in pediatric patients.

BACKGROUND: Pediatric size pneumatically driven extracorporeal ventricular assist devices (VAD) for infants and small children were introduced into clinical routine in 1992. In the initial period, the results in infants were poor. Since then, several improvements have been introduced with regard to the cannulas, connectors, heparin coating of the blood pump inner surface, anticoagulant treatment and coagulation monitoring, and earlier decision-making in favor of pump implantation before irreversible shock has set in. METHODS: Since 1990 and as of January 1, 2005, 62 Berlin Heart Excor systems have been implanted in patients below 18 years of age at our institution. The patients were divided into two groups according to the period of treatment: period 1, devices implanted between 1990 and 1998 (n = 34), and period 2, devices implanted between 1999 and 2004 (n = 28). We compared our experience during the earlier and later periods. RESULTS: There were no significant differences in the preoperative patient data between the two periods except for time of support (17.9 +/- 27.7 days versus 53.2 +/- 83.9 days, p = 0.001). In period 1, more patients needed a biventricular VAD whereas in period 2, more patients were effectively treated with a left VAD (p = 0.05). In the later period, the chest could be primarily closed in a significantly higher percentage of infants (0% versus 89%, p = 0.012), and more infants could be extubated on the VAD (0% versus 55%, p = 0.16). Discharge from the hospital after either weaning from the system or heart transplantation was achieved for 35% in period 1 and for 68% in period 2 (p = 0.029). Whereas in period 1 there were no survivors in the group of children younger than 1 year old, during period 2, survival in this age group was similar to that of the two groups of older children (p = 0.024). There was a significant improvement in the discharge rate in period 2 in patients with cardiomyopathy (43% versus 76%, p = 0.045) and postcardiotomy heart failure (0% versus 57%, p = 0.01). CONCLUSIONS: Earlier implantation of VADs, heparin coating of the blood pumps, and substantial modifications in cannula design, anticoagulation, and the coagulation monitoring regimen have led to a significant increase in the survival and discharge rate, especially among children under 1 year of age. The pediatric size Berlin Heart Excor VAD is a valuable option as a bridge to heart transplantation or recovery for children suffering from cardiogenic shock.

Perfusion education and training in Europe.

Perfusion education and training varies considerably throughout Europe. Unlike in the US, where a common curriculum for perfusion education has been established, each European country has its own education system. This fact is further complicated by a multitude of national languages and cultures. Thus, perfusion education programmes vary, not only in content, but also in their academic levels. This article aims to give a comprehensive overview of the situation in each of the 20 member states of the European Board of Cardiovascular Perfusion (EBCP). The EBCP delegates were polled for a description of the process of training and education of clinical perfusionists in their respective countries. Following the initial delegate poll in 2001, an update of the material was performed in spring 2005. In summary, training of clinical perfusionists in Europe varies considerably between countries. A professional body is necessary to oversee the training process and to guarantee a minimum level of clinical competency for cardiovascular perfusionists.

Transfusion-free cardiopulmonary bypass in Jehovah's Witness patients weighing less than 5 kg.

Performing cardiac surgery on pediatric Jehovah's Witness patients is a great challenge for the surgical team and especially for the perfusionist. Jehovah's Witnesses reject blood transfusions on the grounds of their literal interpretation of passages of the Bible. In accordance with this belief, Jehovah's Witnesses feel that it is also forbidden to retransfuse autologous blood that has been separated from their own circulatory system. We report the use of cardiopulmonary bypass (CPB) during open-heart surgery in three infants with a body weight of 4.5 kg, 3.5 kg, and 3.1 kg, respectively, without transfusion of blood components. A small-volume CPB circuit with a priming volume of 200 mL, including the arterial line filter, was designed to decrease the degree of hemodilution. A dedicated pediatric heart lung machine console with remote pump heads and intensive blood conservation efforts allowed the operation without the use of donor blood. The CPB circuits were primed with crystalloid solution only. The procedures were performed in normothermia or in moderate hypothermia. Pre-CPB hemoglobin levels were 10.8 g/dL, 10.6 g/dL, and 8.5 g/dL. The hemoglobin concentrations measured during CPB ranged from 5.9 to 6.5 g/dL, 6.4 to 6.8 g/dL, and 5.5 to 5.9 g/dL, respectively. The patients did not receive any blood or blood products during their entire hospital stay.

Perfusion technique for nonhaemic cardiopulmonary bypass prime in neonates and infants under 6 kg body weight.

BACKGROUND: Cardiopulmonary bypass (CPB) in neonates and infants is associated with significant haemodilution when priming of the CPB circuit is accomplished without transfusion of homologous blood components. The degree of haemodilution and, thus, the requirements for blood transfusion may be reduced when the CPB circuit is miniaturized without compromising patient safety. METHOD: Between January 2002 and October 2003, selected neonates and small infants were operated on using a nonhaemic prime extracorporeal circuit. CPB priming volume could be reduced from 300 mL to 190 mL by using a dedicated neonatal CPB console with mast-mounted roller pump heads. Reduction of priming volume resulted from shortening of all CPB lines to the minimum, downsizing of all CPB lines, exclusion of unused CPB components, use of vacuum-assisted venous drainage and from close co-operation between the perfusionist, cardiac surgeon and anaesthesiologist. The reduction in priming volume was achieved without eliminating the arterial line filter as safety device. RESULTS: A total of nine patients weighing between 3.2 and 5.9 kg (mean 4.7 kg) and with a body surface area of 0.22-0.35 m2 (mean 0.29 m2) were operated on with the use of the modified neonatal CPB circuit and a nonhaemic prime. Bypass time varied from 38 to 167 min (mean 96 min). The mean haematocrit on CPB was 22.5% with a range of 17-29%. The postoperative course of all patients was uneventful. CONCLUSION: A significant reduction in CPB priming volume makes nonhaemic prime CPB in neonates and small infants undergoing complex repair of congenital heart defects possible.

Extracorporeal elimination of large concentrations of tirofiban by zero-balanced ultrafiltration during cardiopulmonary bypass: an in vitro investigation.

The short-acting platelet glycoprotein IIb/IIIa antagonist tirofiban is beneficial when used in the context of cardiac surgery. Tirofiban has an elimination half-life of 2 h. Renal failure prolongs the half-life and continues inhibition of platelet aggregation refractory to transfusions of platelets. Extracorporeal elimination is necessary to prevent excessive hemorrhage in this condition. We assessed the elimination of tirofiban by hemofiltration in an in vitro model of cardiopulmonary bypass (CPB). Two hemofilters and one plasmapheresis filter were assessed. Three separate filters of each type were tested serially. The CPB circuit was primed with a total volume of 1000 mL. Tirofiban was added to a calculated concentration of 200 ng/mL. Portions of 50 mL of filtrate were retrieved from the dialyzer, and equal amounts of fluid were substituted in the circuit. After each filtration, the tirofiban blood level was analyzed. The procedure was repeated 16 times. Peak tirofiban concentrations ranged from 160 to 260 ng/mL. The elimination of tirofiban followed an exponential decay curve with fast clearance of the large therapeutic concentrations of 250 to 50 ng/mL. The subsidence coefficient b revealed no significant differences in elimination between the filter systems. These data suggest that ultrafiltration is an effective means for extracorporeal elimination of therapeutic levels of tirofiban.

Consumption of blood products during mechanical circulatory support in children: comparison between ECMO and a pulsatile ventricular assist device.

OBJECTIVE: Different mechanical circulatory support (MCS) systems are used in children with intractable heart failure. However, the need for anticoagulation leads to hemorrhage with subsequent use of blood products. We compared the coagulation disorders and the need for blood products in children treated either with extracorporeal membrane oxygenation (ECMO) or with the Berlin Heart pulsatile pneumatic ventricular assist device. PATIENTS: We retrospectively reviewed the first 8-day course of 64 children who were on MCS for more than 2 days between 1990 and 2002. Thirty children (median age 7.4 years, weight 25.5 kg) received Berlin Heart support and 34 children (median age 1.8 years, weight 9.2 kg) ECMO. Anticoagulation was accomplished by continuous infusion of heparin. Red blood cell count, platelet count, aPTT, AT III, fibrinogen, and ACT were measured regularly. Depending on blood loss and the coagulation disorder, red blood cells, fresh frozen plasma, platelets, and AT III were substituted. RESULTS: There were no preoperative differences in hematological parameters between the two groups. In the Berlin Heart group platelet transfusion was 4.3 ml x kg x day vs 24.6 ml x kg x day in the ECMO group. Red blood cell substitution was 17.2 vs 60.3 ml.kg.day. Fresh frozen plasma substitution was 8.5 ml x kg x day vs 46.9 ml x kg x day (P<0.001). Even in the congenital heart defect subgroups, when MCS was implanted without recent cardiotomy, the differences were significant. Nevertheless, the mean daily values for hemoglobin, platelets, and fibrinogen were lower in the ECMO group. There was lower overall mortality in the Berlin Heart group. CONCLUSIONS: Compared to ECMO, use of the Berlin Heart in children results in less blood loss and lower consumption of red blood cells, platelets, and fresh frozen plasma.

Transcontinental transport of a patient with an AbioMed BVS 5000 BVAD.

In patients with severe cardiogenic shock requiring implantation of a short-term assist device transportation to a specialized heart center for further therapy may be necessary. We report the first successful transcontinental air transport (from Singapore to Berlin, Germany) of a patient with fulminating myocarditis requiring implantation of a biventricular assist device.