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.

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.

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.

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.

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.

Measurements of recirculation during neonatal veno-venous extracorporeal membrane oxygenation: clinical application of the ultrasound dilution technique.

Recirculation during dual lumen veno-venous (DLVV) extracorporeal membrane oxygenation (ECMO) is a dynamic event that results in a fraction of the oxygenated blood exiting the arterial lumen and immediately shunting back into the venous lumen. Excessive recirculation will result in suboptimal oxygen delivery to the patient. Ultrasound dilution is a technology that has been shown to rapidly quantify recirculation in veno-venous (VV) ECMO animal models. This manuscript reports the first clinical application of ultrasound dilution in quantifying recirculation during neonatal VV ECMO. A 2.8-kg neonate with congenital diaphragmatic hernia was placed on VV ECMO using a single DLVV cannula inserted into the right atrium through the internal jugular vein. Ultrasound sensors were clamped to the arterial and venous lines near the dual lumen cannula and 3- to 5-mL bolus injections of isotonic saline were used proximal to the circuit heat exchanger to make the recirculation measurements. Recirculation measurements were made after initiation and periodically thereafter. During the 12-day ECMO period, 86 recirculation measurements were performed. The average recirculation was 34.3% (range, 15-57%). Reproducibility of paired measurements was 5.6%. Changes in patient positioning resulted in significant changes in recirculation. Measurements using platelet injections were compared with those made with saline. The two were found to closely correlate (mean difference, .25% +/- 2.8%). Ultrasound dilution measurements of recirculation provided rapid monitoring data during a clinical VV ECMO procedure. Application of this technique could provide early data that will assist the clinician in guiding interventions to minimize recirculation.

The potential of accurate SvO2 monitoring during venovenous extracorporeal membrane oxygenation: an in vitro model using ultrasound dilution.

INTRODUCTION: Some degree of recirculation occurs during venovenous extracorporeal membrane oxygenation (VV ECMO) which, (1) reduces oxygen (O2) delivery, and (2) renders venous line oxygen saturation monitoring unreliable as an index of perfusion adequacy. Ultrasound dilution allows clinicians to rapidly monitor and quantify the percent of recirculation that is occurring during VV ECMO. The purpose of this paper is to test whether accurate patient mixed venous oxygen saturation (SvO2) can be calculated once recirculation is determined. It is hypothesized that it is possible to derive patient mixed venous saturations by integrating recirculation data with the ECMO circuit arterial and venous line oxygen saturation data. METHODS: A test system containing sheep blood adjusted to three venous saturations (low-30%, med-60%, high-80%) was interfaced via a mixing chamber with a standard VV ECMO circuit. Recirculation, arterial line and venous line oxygen saturations were measured and entered into a derived equation to calculate the mixed venous saturation. The resulting value was compared to the actual mixed venous saturation. RESULTS: Recirculation was held constant at 30.5 +/- 2.0% for all tests. A linear regression comparison of "actual" versus "calculated" mixed venous saturations produced a correlation coefficient of R2 = 0.88. Direct comparison of actual versus calculated saturations for all three test groups respectively are as follows; Low: 31.8 +/- 3.95% vs. 37.0 +/- 6.7% (NS), Med: 61.7 +/- 1.5% vs. 72.3 +/- 1.8% (p < 0.05), High: 84.4 +/- 0.9% vs. 91.2 +/- 1.1% (p < 0.05). DISCUSSION: There was a strong correlation between actual and calculated mixed venous saturations; however, significant differences between actual and calculated values where observed at the Med and High groups. While this data suggests that using quantified recirculation data to calculate SvO2 is promising, it appears that a straightforward derivative of the oxygen saturation-based equation may not be sufficient to produce clinically accurate calculations of actual mixed venous saturations.