Simulated cardiopulmonary bypass: a high fidelity model for developing and accessing clinical perfusion skills.

BACKGROUND: Traditionally, novice perfusionists learn and practice clinical skills, during live surgical procedures. The profession's accrediting body is directing schools to implement simulated cardiopulmonary bypass (CPB) into the curriculum. Unfortunately, no CPB simulation models have been validated. Here we describe the design and application of a CPB simulation model. METHODS: A CPB patient simulator was integrated into a representative operative theater and interfaced with a simple manikin, a heart-lung machine (HLM), clinical perfusion circuitry, and equipment. Participants completed a simulation scenario designed to represent a typical CPB procedure before completing an exit survey to assess the fidelity and validity of the experience. Questions were scored using a 5-point Likert scale. RESULTS: Participants (n = 81) contributed 953 opinions on 40 questions. The participants reported that the model of simulated CPB (1) realistically presented both the physiologic and technical parameters seen during CPB (n = 347, mean 4.37, SD 0.86), (2) accurately represented the psychological constructs and cognitive mechanisms of the clinical CPB (n = 139, mean 4.24, SD 1.08), (3) requires real clinical skills and reproduces realistic surgical case progression (n = 167, mean 4.38, SD 0.86), and (4) would be effective for teaching, practicing, and assessing the fundamental skills of CPB (n = 300, mean 4.54, SD 0.9). Participants agreed that their performance in the simulation scenario accurately predicted their performance in a real clinical setting (n = 43, mean 4.07, SD 1.03) CONCLUSION: This novel simulation model of CPB reproduces the salient aspects of clinical CPB and may be useful for teaching, practicing, and assessing fundamental skills.

The use of protective mechanical ventilation during extracorporeal membrane oxygenation for the treatment of acute respiratory failure.

Acute respiratory failure (ARF) strikes an estimated two million people in the United States each year, with care exceeding US$50 billion. The hallmark of ARF is a heterogeneous injury, with normal tissue intermingled with a large volume of low compliance and collapsed tissue. Mechanical ventilation is necessary to oxygenate and ventilate patients with ARF, but if set inappropriately, it can cause an unintended ventilator-induced lung injury (VILI). The mechanism of VILI is believed to be overdistension of the remaining normal tissue known as the 'baby' lung, causing volutrauma, repetitive collapse and reopening of lung tissue with each breath, causing atelectrauma, and inflammation secondary to this mechanical damage, causing biotrauma. To avoid VILI, extracorporeal membrane oxygenation (ECMO) can temporally replace the pulmonary function of gas exchange without requiring high tidal volumes (VT) or airway pressures. In theory, the lower VT and airway pressure will minimize all three VILI mechanisms, allowing the lung to 'rest' and heal in the collapsed state. The optimal method of mechanical ventilation for the patient on ECMO is unknown. The ARDSNetwork Acute Respiratory Management Approach (ARMA) is a Rest Lung Approach (RLA) that attempts to reduce the excessive stress and strain on the remaining normal lung tissue and buys time for the lung to heal in the collapsed state. Theoretically, excessive tissue stress and strain can also be avoided if the lung is fully open, as long as the alveolar re-collapse is prevented during expiration, an approach known as the Open Lung Approach (OLA). A third lung-protective strategy is the Stabilize Lung Approach (SLA), in which the lung is initially stabilized and gradually reopened over time. This review will analyze the physiologic efficacy and pathophysiologic potential of the above lung-protective approaches.

Effect of low dose acetylsalicylic acid and anticoagulant on clinical outcomes in COVID-19, analytical cross-sectional study.

Background and aims: The therapeutic strategy for the treatment of known sequelae of COVID-19 has shifted from reactive to preventative. In this study, we aim to evaluate the effects of acetylsalicylic acid (ASA), and anticoagulants on COVID-19 related morbidity and mortality. Methods: This record-based analytical cross-sectional study targeted 539 COVID-19 patients in a single United States medical center between March and December 2020. Through a random stratified sample, we recruited outpatient (n = 206) and inpatient (n = 333) cases from three management protocols, including standard care (SC) (n = 399), low-dose ASA only (ASA) (n = 112), and anticoagulation only (AC) (n = 28). Collected data included demographics, comorbidities, and clinical outcomes. The primary outcome measure was inpatient admission. Exploratory secondary outcome measures included length of stay, 30-day readmission rates, medical intensive care unit (MICU) admission, need for mechanical ventilation, the occurrence of acute respiratory distress syndrome (ARDS), bleeding events, clotting events, and mortality. The collected data were coded and analyzed using standard tests. Results: Age, mean number of comorbidities, and all individual comorbidities except for asthma, and malignancy were significantly lower in the SC compared to ASA and AC. After adjusting for age and comorbidity via binary logistic regression models, no statistical differences were found between groups for the studied outcomes. When compared to the SC group, ASA had lower 30-day readmission rates (odds ration [OR] 0.81 95% confidence interval [CI] 0.35-1.88, p = 0.63), MICU admission (OR 0.63 95% CI 0.34-1.17, p = 0.32), ARDS (OR 0.71 95% CI 0.33-1.52, p = 0.38), and death (OR 0.85 95% CI 0.36-1.99, p = 0.71). Conclusion: Low-dose ASA has a nonsignificant but potentially protective role in reducing the risk of COVID-19 related morbidity and mortality. Our data suggests a trend toward reduced 30-day readmission rates, ARDS, MICU admissions, need for mechanical ventilation, and mortality compared to the standard management protocol. Further randomized control trials are needed to establish causal effects.

Ultrafiltration and cardiopulmonary bypass associated acute kidney injury: A systematic review and meta-analysis.

BACKGROUND: Cardiopulmonary bypass is known to raise the risk of acute kidney injury (AKI). Previous studies have identified numerous risk factors of cardiopulmonary bypass including the possible impact of perioperative ultrafiltration. However, the association between ultrafiltration (UF) and AKI remains conflicting. Thus, we conducted a meta-analysis to further examine the relationship between UF and AKI. HYPOTHESIS: Ultrafiltration during cardiac surgery increases the risk of developping Acute kidney Injury. METHODS: We searched PubMed, Web of Science, EBSCO, and SCOPUS through July 2021. The RevMan (version 5.4) software was used to calculate the pooled risk ratios (RRs) and mean differences along with their associated confidence intervals (95% CI). RESULTS: We identified 12 studies with a total of 8005 patients. There was no statistically significant difference in the incidence of AKI between the group who underwent UF and the control group who did not (RR = 0.90, 95% CI = 0.64-1). Subgroup analysis on patients with previous renal insufficiency also yielded nonsignificant difference (RR = 0.84, 95% CI = 0.53 -1.33, p = .47). Subgroup analysis based on volume of ultrafiltrate removed (> or <2900 ml) was not significant and did not increase the AKI risk as predicted (RR = 0.82, 95% CI = 0.63 -1.07, p = .15). We also did subgroup analysis according to the type of UF and again no significant difference in AKI incidence between UF groups and controls was observed in either the conventional ultrafiltration (CUF), modified ultrafiltration (MUF), zero-balanced ultrafiltration (ZBUF), or combined MUF and CUF subgroups. CONCLUSION: UF in cardiac surgery is not associated with increased AKI incidence and may be safely used even in baseline chronic injury patients.

Acetylsalicylic Acid Compared with Enoxaparin for the Prevention of Thrombosis and Mechanical Ventilation in COVID-19 Patients: A Retrospective Cohort Study.

BACKGROUND AND OBJECTIVE: Low-dose acetylsalicylic acid (ASA, aspirin) is a well-known and frequently studied drug for primary and secondary prevention of disease due to its anti-inflammatory and coagulopathic effects. COVID-19 complications are attributed to the role of thrombo-inflammation. Studies regarding the use of low-dose ASA in COVID-19 are limited. For this reason, we propose that the use of low-dose ASA may have protective effects in COVID-19-related thromboembolism and lung injury. This study was conducted to assess the efficacy of low-dose ASA compared with enoxaparin, an anticoagulant, for the prevention of thrombosis and mechanical ventilation. METHODS: We conducted a retrospective cohort study on COVID-19-confirmed hospitalized patients at the Mansoura University Quarantine Hospital, outpatients, and home-isolated patients from September to December 2020 in Mansoura governorate, Egypt. Binary logistic regression analysis was used to assess the effect of ASA compared with enoxaparin on thromboembolism, and mechanical ventilation needs. RESULTS: This study included 225 COVID-19 patients. Use of ASA-only (81-162 mg orally daily) was significantly associated with reduced thromboembolism (OR 0.163, p = 0.020), but both low-dose ASA and enoxaparin, and enoxaparin-only (0.5 mg/kg subcutaneously (SC) daily as prophylactic dose or 1 mg/kg SC every 12 hours as therapeutic dose) were more protective (odds ratio [OR] 0.010, OR 0.071, respectively, p < 0.001). Neither ASA-only nor enoxaparin-only were associated with a reduction in mechanical ventilation needs. Concomitant use of low-dose ASA and enoxaparin was associated with reduced mechanical ventilation (OR 0.032, 95% CI 0.004-0.226, p = 0.001). CONCLUSIONS: Low-dose ASA-only use may reduce the incidence of COVID-19-associated thromboembolism, but the reduction may be less than that of enoxaparin-only, and both ASA and enoxaparin. Concomitant use of ASA and enoxaparin demonstrates promising results with regard to the reduction of thrombotic events, and mechanical ventilation needs.

Rationales and uncertainties for aspirin use in COVID-19: a narrative review.

OBJECTIVES: To review the pathophysiology of COVID-19 disease, potential aspirin targets on this pathogenesis and the potential role of aspirin in patients with COVID-19. DESIGN: Narrative review. SETTING: The online databases PubMed, OVID Medline and Cochrane Library were searched using relevant headlines from 1 January 2016 to 1 January 2021. International guidelines from relevant societies, journals and forums were also assessed for relevance. PARTICIPANTS: Not applicable. RESULTS: A review of the selected literature revealed that clinical deterioration in COVID-19 is attributed to the interplay between endothelial dysfunction, coagulopathy and dysregulated inflammation. Aspirin has anti-inflammatory effects, antiplatelet aggregation, anticoagulant properties as well as pleiotropic effects on endothelial function. During the COVID-19 pandemic, low-dose aspirin is used effectively in secondary prevention of atherosclerotic cardiovascular disease, prevention of venous thromboembolism after total hip or knee replacement, prevention of pre-eclampsia and postdischarge treatment for multisystem inflammatory syndrome in children. Prehospital low-dose aspirin therapy may reduce the risk of intensive care unit admission and mechanical ventilation in hospitalised patients with COVID-19, whereas aspirin association with mortality is still debatable. CONCLUSION: The authors recommend a low-dose aspirin regimen for primary prevention of arterial thromboembolism in patients aged 40-70 years who are at high atherosclerotic cardiovascular disease risk, or an intermediate risk with a risk-enhancer and have a low risk of bleeding. Aspirin's protective roles in COVID-19 associated with acute lung injury, vascular thrombosis without previous cardiovascular disease and mortality need further randomised controlled trials to establish causal conclusions.

The Effectiveness of Three Different Curricular Models to Teach Fundamental ECMO Specialist Skills to Entry Level Perfusionists.

The dramatic increase in the use of extracorporeal membrane oxygenation (ECMO) over the last decade with the concomitant need for ECMO competent perfusionists has raised questions of how well perfusion education programs are preparing entry-level perfusionists to participate in ECMO. While all perfusion schools teach ECMO principles, there is no standardized or systematic approach to the delivery of didactic knowledge and clinical skills in ECMO. Given this variability of ECMO education across and within perfusion schools, the CES-A exam may provide a metric for comparing curricular approaches. The purpose of this study is to examine three different curricular approaches to prepare new perfusion graduates to master the Adult ECMO Specialist Certification exam (CES-A). We examined three different curricular approaches to prepare new perfusion graduates to master the Adult ECMO Specialist Certification exam (CES-A). We hypothesized that there would be no difference in CES-A pass rate, exam score, Rasch measure, and item category scores between SUNY Cardiovascular Perfusion Program (CVP) graduates who completed SUNY's ECMO Capstone experience (Group III) and CVP graduates who did not select the ECMO Capstone experience (Group II). Further, we studied the performance of a third group of new graduates from an external program that does not offer formal ECMO courses or an ECMO Capstone experience (Group I). Every perfusion graduate in all groups passed the adult ECMO specialist exam. The graduates who as students completed an ECMO Capstone experience (Group III) scored higher on the exam and significantly higher on four exam categories: coagulation and hemostasis (p = .058), lab analysis point of care (p = .035), and monitor patient and circuit (p = .073), and the safety and failure modes (p = .017). Overall the median graduate Rasch measures ranked with Group III demonstrating the highest measure to Group I the lowest measures (not significant at p = .085). There is a positive educational effect due to CVP graduates completion of the ECMO Capstone experience compared to the program standard ECMO-related curricula in the two perfusion programs participating in this study. From this observation a structured ECMO simulation-based program appears to be equally effective as a traditional, typical lecture-only, clinical perfusion preceptorship, while demonstrating a more satisfactory experience with a higher reported case experience. In this study the standard perfusionist education curriculum prepared the new graduate to be successful on the CES-A exam. The three curricular approaches appear to prepare perfusionist graduates to be successful on the Adult ECMO Specialist exam.

The Fundamental Skills and Deconstructed Sub-Steps of Pediatric Cardiopulmonary Bypass.

Perfusion education programs use simulation to provide students with clinical skills prior to entering the operating room. To teach the psychomotor execution of skills in a simulation lab requires a list of validated skills and deconstructed sub-steps to fully optimize adult learning. A list of the fundamental skills of adult cardiopulmonary bypass (CPB) was recently published; however, no defined list exists regarding pediatric CPB skills. The purpose of this survey is to form a definitive list of skills fundamental to pediatric CPB. A survey of 23 proposed pediatric CPB clinical skills and 291 proposed skill sub-steps was developed. Proposed pediatric CPB skills were evaluated using an established frequency and harm index. If the skill is performed >50% of the time (frequency), and if >50% believe that if the skill is performed incorrectly patient harm is probable (risk), then the skill is accepted as fundamental. The survey content was validated by subject matter experts and then distributed to practicing perfusionists between September 2020 and December 2020. Of the 125 survey respondents, 57.9% had 10 or more years in the field. 35.2% of respondents are American Society of Extracorporeal Technology (AmSECT) Fellows of Pediatric Perfusion (FPP) and pediatric CPB represents >50% of the annual caseload for 69.7% of respondents. 22 of the 23 proposed skills were accepted as fundamental in the conduct of pediatric CPB and 258 of the 291 proposed sub-steps associated with CPB skills were accepted as integral to skill performance. By surveying practicing pediatric perfusionists, this study identifies 22 skills as fundamental to the safe execution of pediatric CPB. In addition, skill sub-elements were identified as necessary for skill execution. This knowledge will assist perfusion programs in developing a pediatric simulation curriculum that matches current clinical execution of pediatric skills.

Objective Content Validation of the Hemodynamic and Technical Parameters of the OrpheusTM Cardiopulmonary Bypass Simulator.

The utilization of simulators for training is increasing in the professions associated with cardiac surgery. Before applying these simulators to high-stakes assessment, the simulator's output data must be validated. The aim of this study is to validate a Cardiopulmonary Bypass (CPB) simulator by comparing the simulated hemodynamic and technical outputs to published clinical norms. Three Orpheus™ CPB simulators were studied and compared to a published reference of physiologic and technical metrics that are managed during clinical CPB procedures. The limits of the simulators user modifiable variables were interrogated across their full range and the results were plotted against the published clinical norms. The data generated with the simulator conforms to validated clinical parameters for patients between 50 and 110 kg. For the pre- and post-CPB periods, the independent variables of central venous pressure (CVP), heart rate (HR), contractility, and systemic vascular resistance (SVR) must be operated between the limits of 7 and 12 mmHg, 65 and 110 beats/min, 28% and 65%, and 6 and 32 units respectively. During full CPB the arterial pump flows should be maintained between 3.5 and 5.5 LPM and SVR between 18 and 38 units. Validated technical parameters during cardioplegia delivery are expected at solution flow rates between 250 and 400 mL/min and 100 and 225 mL/min for antegrade and retrograde delivery routes, respectively. We have identified the limits for user-modifiable settings that produce data conforming to the physiologic and technical parameter limits reported in the peer reviewed literature. These results can inform the development of simulation scenarios used for high stakes assessments of personnel, equipment, and technical protocols.

Legislating for a Pandemic: Exposing the Stateless State.

Initially the subject of widespread consensus, legislative and policy responses to COVID-19 are increasingly provoking predictable reactions. Right and left are united by concern that essential freedoms are being eroded by a state utilizing the opportunity of the pandemic to make a power grab. Focused on the Coronavirus Act 2020, this article takes a more cautious approach, suggesting that the law should be understood not as the product of a hierarchical state but as a demonstration of the 'statelessness' of the contemporary state. It examines the Act with particular focus on open justice, adult social care, and Business Improvement Districts. Reading this unique piece of legislation through the lens of the stateless state reveals the complexities, ambiguities, and contestations within contemporary policy making. Dismissing the Act as unnecessarily authoritarian is an insufficiently nuanced response; furthermore, this exploration of the law allows us to develop and complicate scholarship on the stateless state.

Survey of the Routine Practice Limits for Physiologic and Technical Parameters Managed by Clinical Perfusionists during Adult Cardiopulmonary Bypass.

Cardiopulmonary bypass (CPB) is a highly technical clinical discipline with a recognized variability in practice. Professional standards and guidelines documents help direct clinical practice and reduce variability, but these guidelines are necessarily vague and fall short of providing specific objective recommendations of clinical practice metrics. If clinical practice metrics were known, they would be informative when writing departmental policy manuals, structuring quality improvement initiatives, describing product R&D specifications, and designing educational assessment rubrics. Therefore, to address this gap, we conducted a national survey of clinical practice with the purpose of producing a benchmark of the typical variability of specific technical parameters that are commonly managed during adult CPB procedures. A pool of expert clinical perfusionists collaborated to compile a data set of normal ranges for 41 individual physiologic and technical parameters (pressures, flows, saturation, times, solutions, and temperatures) that are commonly managed during adult CPB procedures. Results were collected using an online survey application. Respondent demographics and measures of central tendency with descriptive quartile statistics and confidence intervals for each parameter are presented. Of the 335 people who participated in the survey, 315 met the inclusion criteria. The geographic demographics of the respondents were representative of the American Board of Cardiovascular Perfusion's distribution of certified clinical perfusionists. Of the 41 parameters investigated, there were 13 hemodynamic parameters, 13 normal flow rates and technical circuit parameters, 10 blood gasses and hematocrit parameters, and five parameters of patient temperatures. The data presented here are informative and provide a consensus-based objective assessment of the standard practice for adult CPB as reported by practicing clinical perfusionists. Based on these survey data, we have identified the typical clinical limits for the 41 parameters that are managed during adult CPB. This information may be incorporated into guiding documents to support the work of clinicians, researchers, and educators.

Development of the Adult ECMO Specialist Certification Examination.

The American Society of Extracorporeal Technology Board of Directors, consistent with the American Society of Extracorporeal Technology's safe patient care improvement mission, charged the International Board of Blood Management to write a knowledge and skill certification examination for healthcare personnel employed as adult extracorporeal membrane oxygenation (ECMO) specialists. Nineteen nationally recognized ECMO subject-matter experts were selected to complete the examination development. A job analysis was performed, yielding a job description and examination plan focused on 16 job categories. Multiple-choice test items were created and validated. Qualified ECMO specialists were identified to complete a pilot examination and both pre- and post-examination surveys. The examination item difficulty and candidate performance were ranked and matched using Rasch methodology. Candidates' examination scores were compared with their profession, training, and experience as ECMO specialists. The 120-item pilot examination form ranked 76 ECMO specialist candidates consistent with their licensure, ECMO training, and clinical experience. Forty-three registered nurses, 28 registered respiratory therapists, four certified clinical perfusionists, and one physician assistant completed the pilot examination process. Rasch statistics revealed examination reliability coefficients of .83 for candidates and .88 for test items. Candidates ranked the appropriateness for examination items consistent with the item content, difficulty, and their personal examination score. The pilot examination pass rate was 80%. The completed examination product scheduled for enrollment in March 2020 includes 100 verified test items with an expected pass rate of 84% at a cut score of 67%. The online certification examination based on a verified job analysis provides an extramural assessment that ranks minimally prepared ECMO specialists' knowledge, skills, and abilities (KSA) consistent with safe ECMO patient care and circuit management. It is anticipated that ECMO facilities and ECMO service providers will incorporate the certification examination as part of their process improvement, safety, and quality assurance plans.

Fundamental clinical skills of adult cardiopulmonary bypass: results of the 2017 national survey.

INTRODUCTION: Training students to become entry-level perfusionists requires evaluation and assessment of their clinical skills. While our professional organizations have compiled resources which identify the profession's knowledge base and categorical skills applied to clinical practice, these resources are lacking the necessary detail to develop validated clinical assessment rubrics. Therefore, the purpose of this project is to identify, through expert opinion, the detailed fundamental skills necessary to perform adult cardiopulmonary bypass (CPB). METHODS: We define a fundamental skill based upon frequency of use and risk of harm. A skill that experts report is conducted in >50% of their CPB cases - and, if not properly conducted, can cause harm, is deemed a fundamental skill. To identify these skills, a 73-question survey was developed and posted on PerfList and PerfMail from May 2017 to July 2017. RESULTS: The results from 261 respondents were analyzed. The demographics of the participants were representative of the workforce. Twenty skills were surveyed and all 20 met the criteria to be identified as a fundamental skill. Data regarding the actions, assessments and behaviors that may be associated with fundamental skills were also identified. CONCLUSIONS: Based upon this survey data, we have identified that there is consensus within our profession regarding the fundamental skills of adult CPB and a core body of actions, assessments and behaviors that experts perform when conducting these skills. This information may be incorporated into the entry-level educational process to inform curricula and design valid assessment rubrics.

Preserving ECMO Cannulae Patency.

Extracorporeal membrane oxygenation (ECMO) is often managed using minimal anticoagulation. This can make the circuitry susceptible to thrombosis. The ECMO cannula may be particularly vulnerable to thrombosis if flow is interrupted for an undetermined but prolonged period of time. Therefore, under conditions where cannula blood flow stasis may be prolonged and flashing, the cannulae is not an option (e.g., air in circuit) it is imperative to have an emergency plan available, which can be rapidly implemented that will provide a means of cannula patency preservation. The following outlines a system to preserve cannula patency in these instances.

Staffing, Equipment, Monitoring Considerations for Extracorporeal Membrane Oxygenation.

Although the reasons for the recent growth in adult extracorporeal membrane oxygenation (ECMO) are multifactorial, much of the success may be attributed to the development of well-trained staff and the technological innovations in equipment and monitoring devices used during extracorporeal support. In this article, the authors discuss general educational formats for the ECMO bedside provider, staffing support models, and devices designed to best meet the needs of the patient while simultaneously ensuring the proper delivery of ECMO-related care.

Vacuum-Assisted Venous Drainage: A 2014 Safety Survey.

Despite the widespread use of vacuum-assisted venous drainage (VAVD) and case reports describing catastrophic incidents related to VAVD, there is a lack of data cataloging specific safety measures that individuals and institutions have incorporated into their VAVD practices for the prevention of these incidents. Therefore, the purpose of this study is to survey the perfusion community to gather data on VAVD practices, and to compare these current practices with literature recommendations and the American Society of ExtraCorporeal Technology (AmSECT) Standards and Guidelines. In September 2014, a survey was distributed via PerfList and PerfMail, and by direct e-mail to members of the New York State Society of Perfusionists, targeting certified clinical perfusionists in New York State. Survey topics pertaining to VAVD practice included 1) equipment, 2) pressure monitoring and alarms, 3) protocols, checklists, and documentation, and 4) VAVD-related incidents. Of ∼200 certified clinical perfusionists who live and/or work in New York State (NYS), 88 responded (42%). Most respondents (90.1%) report they use VAVD. Of these, 87.3% report that they monitor VAVD pressure, with 51.6% having audible and visual alarms for both positive and excessive negative pressures. At the institutional level, 61.2% of respondents reported that there is a protocol in place at for their team limiting negative pressure in the reservoir, 28.4% document VAVD pressure in the pump record, and AmSECT's three recommended VAVD checklist items are met with 53.7%, 55.1%, and 33.8% compliance. In conclusion, the results of this study reveal that the use of VAVD has increased and has become nearly universal in 2014. There is high compliance to some of the literature recommendations and AmSECT Standards and Guidelines, however, there are still some gaps between current practices and these recommendations. Continued improvement, both at the individual and institutional levels, will help to improve patient safety by preventing untoward events from occurring while using VAVD.

A 2013 Survey on Pressure Monitoring in Adult Cardiopulmonary Bypass Circuits: Modes and Applications.

Pressure data acquired from multiple sites of extracorporeal circuits can be an important parameter to monitor for the safe conduct of cardiopulmonary bypass (CPB). Although previous surveys demonstrate that CPB circuit pressure monitoring is widely used, there are very little data cataloging specific applications of this practice. Therefore, the purpose of this study is to survey the perfusion community to catalog 1) primary CPB circuit site pressure monitoring locations; 2) type of manometers used; 3) pressure monitoring interface and servoregulation with pump console; and 4) the rationale and documentation associated with pressure monitoring during CPB. In June 2013, a validated 27-question online survey was sent directly through an e-mail link to the chief perfusionists in the northeast United States. Completed surveys were received from 75 of 117 surveys deployed yielding a 64% response rate. Arterial line pressure monitoring during CPB is reported by 99% with six distinct circuit site locations identified. Cardioplegia system pressure was monitored by 95% of the centers. For vacuum-assisted venous drainage (VAVD) users, the venous pressure was measured by 72% of the responding centers. Arterial line pressure servoregulation of the arterial pump was indicated by 61% of respondents and 75% of centers record arterial line pressure in their perfusion record. Most centers (77%) report the use of a transducer that is integrated into the pump console providing a digital pressure display, whereas 20% combine an aneroid gauge manometer with the integrated digital transducer. This study demonstrates that the practice of arterial line pressure monitoring during CPB is nearly universal. However, the selection of the pressure monitoring site on the circuit, modes of monitoring pressure, and their applications are highly variable across the perfusion community.

Validation of cardiac output measurement by ultrasound dilution technique with pulmonary artery thermodilution in a pediatric animal model.

Novel COstatus system (Transonic Systems, Inc., NY), based on ultrasound dilution (UD), works off in situ arterial and central venous catheters in pediatric patients to measure cardiac output (CO). The purpose of the present study was to validate CO measurement by UD (COUD) with pulmonary artery (PA) thermodilution (COTD) in a prospective animal study. Ten anesthetized pigs (16-45 kg) were instrumented with pediatric PA, central venous, and peripheral artery catheters. For COUD measurements, normothermic saline (0.5-1.0 ml/kg body weight, up to a maximum of 30 ml) was injected into the venous limb of an arteriovenous loop that was connected between in situ catheters. For COTD measurements, 5-10 ml cold saline was injected into the PA catheter. Sixty-four averaged sets were obtained for comparison. COTD mean was 2.98 ± 1.21 l/min (range 1.33-6.29), and COUD mean was 2.68 ± 1.16 l/min (range 1.33-5.85). This study yielded a correlation r = 0.96, COUD = 0.91*(COTD) - 0.04 l/min; bias was 0.3 l/min with limits of agreement as -0.39 to 0.99 l/min; and the percentage error was 23.73% between the methods. CO measurements by UD agreed well with thermodilution measurements in the pediatric swine model.

Oxygenator change-out times: the value of a written protocol and simulation exercises.

A survey by our department revealed that most of the institutions in New England and New York have written protocols for low-volume, high-risk, emergency events but few of these centers formally practice these protocols through simulation. We hypothesized that hands-on experience with medical emergency protocols will significantly improve clinician performance. Two groups (n = 24 each) of third semester perfusion students with comparable clinical skills were enrolled in this study. The first group was surprised with an emergent oxygenator change-out drill during a simulation exercise, with no prior warning and without the benefit of a written protocol. The second group was asked to develop a written protocol before they were challenged with the change-out drill. Subsequently, both groups were given a week to practice a protocol for emergent change-out before re-testing. The times for all change-out drills were recorded and the groups were compared with a Student's t-test. A p-value < 0.05 was considered significant. The group without a written protocol (NP) had the longer time (559.7 +/- 84.9 sec) while the group with the written protocol (P) performed better (461.8 +/- 57.5 sec, p < 0.05). However, both groups achieved significantly better performance following repeated practice (NP = 167.8 +/- 34.8; P = 170.9+/-32.5 sec, p < 0 .05). While written protocols for emergent events will improve patient care, simulation and practice of emergency protocols is the most significant way to protect our patients. Based on this, we advocate for all perfusion groups to simulate emergency events and practice their crisis protocols.

Calculating mixed venous saturation during veno-venous extracorporeal membrane oxygenation.

INTRODUCTION: Recirculation (R), the shunting of arterial blood back into to the venous lumen, commonly occurs during veno-venous extracorporeal membrane oxygenation (VV-ECMO) and renders the monitoring of the venous line oxygen saturation no longer reflective of patient mixed venous oxygen saturation (S(V)O(2)). Previously, we failed to prove the hypothesis that, once R is known, it is possible to calculate the S(V)O(2) of a patient on VV-ECMO. We hypothesize that we can calculate S(V)O(2) during VV-ECMO if we account for and add an additional correction factor to our model for dissolved oxygen content. Therefore, the purpose of this study is to derive a more accurate model that will allow clinicians to determine S(V)O(2) during VV-ECMO when ultrasound dilution is being used to quantify R. METHODS: Using an extracorporeal circuit primed with fresh porcine blood, two stocks of blood were produced; (1) arterial blood (AB), and (2) venous blood (VB). To mimic recirculation, the AB and VB were mixed together in precise ratios using syringes and a stopcock manifold. Six paired stock AB/VB sets were prepared. Two sets were mixed at 20% R increments and 4 sets were mixed at 10% R increments. The partial pressure of oxygen (pO(2) ) and oxygen (O(2)) saturation of the stock blood and resultant mixed blood was determined. The original model was modified by modeling the residual errors with linear regression. RESULTS: When using the original model, as the partial pressure of arterial oxygen (P(a)O( 2)) of the stock AB increased, the calculated S(V)O(2) was higher than actual, especially at higher R levels. An iteration of the original model incorporating the P(a)O(2) level (low, medium, high) and R was derived to fit the data. CONCLUSIONS: The original model using R and circuit saturations for the calculation of S(V)O( 2) in VV-ECMO patients is an oversimplification that fails to consider the influence of the high pO(2) of arterial blood during therapy. In the future, further improvements in this model will allow clinicians accurately to calculate S(V)O(2) in conjunction with recirculation measurements.