Incident Reporting in Perfusion: Current Perceptions on PIRS-2.

The Australia and New Zealand College of Perfusionists' (ANZCP) Perfusion Incident Reporting System was established in 1998 and has evolved to an open access on-line incident perfusion reporting system (PIRS-2). Changes were made to PIRS-2 to promote learning from what went well in unexpected situations. A 9-question survey was e-mailed to the PIRS-2 contact group to elicit feedback on attitudes to voluntarily reporting perfusion-related incidents and near-miss events to PIRS-2. In August 2019, a 9-question survey using SurveyMonkey® (San Mateo Ca) was e-mailed to 198 perfusionists currently on the ANZCP PIRS-2 e-mail contacts group. Responses for all responding practicing perfusionists were totaled and expressed as a percentage of the total number of respondents. The respondents were then grouped by region and responses were expressed as a percentage of respondents from each region as well as for grouped responses from Australia/New Zealand (ANZ) and non-ANZ respondents. The response rate was 49.5% with 95 practicing perfusionists completing the survey. In the 12 months before the survey, 22% of respondents had submitted reports to PIRS-2, whereas 79% had read e-mailed reports. Unit culture was the most frequently cited barrier to reporting from all respondents (19%; 0% to 40% by region). Twenty-five percentage of Australian respondents cited unit culture as a barrier to reporting vs. 0% of New Zealand respondents. A combination of concern of discovery and identification of region ranked second as a barrier for 17% of all respondents. The open access ANZCP PIRS-2 voluntary incident reporting in perfusion was widely viewed as relevant and beneficial to both individual practice and to team performance. A high likelihood to considering reporting incidents is tempered by the well-established barriers of ease of the reporting system, the fix and forget phenomenon, concerns of discovery, and a defensive unit culture.

Cardiopulmonary bypass management and acute kidney injury in 118 Jehovah's Witness patients: a retrospective propensity-matched multicentre cohort from 30,942 patients.

INTRODUCTION: Patients refusing blood products in cardiac surgery present challenges for cardiopulmonary bypass. Accurate detail of the modifiable factors of cardiopulmonary bypass relating to acute kidney injury is previously unreported in this patient population. METHODS: A total of 118 adult Jehovah's Witness patients refusing transfusion were propensity matched to 118 adult patients accepting transfusion from the 30,942 patients in the Australian and New Zealand Collaborative Perfusion Registry. The primary endpoint was acute kidney injury. Intraoperative and bypass management characteristics were also compared between early (2007-2012) and late (2013-2018) cohorts along with the acceptance or refusal of transfusion. RESULTS: In patients accepting transfusion, 49% received a blood product. In patients refusing transfusion, acute kidney injury was lower (8% vs. 22%; p = 0.003) cell salvage use was higher (70% vs. 22%; p < 0.001), as was use of haemofiltration (8% vs. 4%; p = 0.03) and tranexamic acid in the early period (87% vs. 62%, p = 0.004) but not late (100% vs. 97%; p = 0.15). There was no difference in modifiable cardiopulmonary bypass factors (mean arterial pressure, minimum oxygen delivery (DO2i), retrograde autologous prime, circuit prime volume) between the two groups; however, prime volume decreased and DO2i increased over time for both. Patients refusing transfusion had lower postoperative blood loss (p = 0.02) and shorter postoperative length of stay (p < 0.001) with no difference in morbidity (p = 0.46) or mortality (p = 0.68). CONCLUSION: Refusal of transfusion in patients undergoing cardiopulmonary bypass was associated with reduced acute kidney injury, hospital stay and postoperative blood loss, while not impacting mortality.

Is Conventional Bypass for Coronary Artery Bypass Graft Surgery a Misnomer?

Although recent trials comparing on vs. off-pump revascularization techniques describe cardiopulmonary bypass (CPB) as "conventional," inadequate description and evaluation of how CPB is managed often exist in the peer-reviewed literature. We identify and subsequently describe regional and center-level differences in the techniques and equipment used for conducting CPB in the setting of coronary artery bypass grafting (CABG) surgery. We accessed prospectively collected data among isolated CABG procedures submitted to either the Australian and New Zealand Collaborative Perfusion Registry (ANZCPR) or Perfusion Measures and outcomes (PERForm) Registry between January 1, 2014, and December 31, 2015. Variation in equipment and management practices reflecting key areas of CPB is described across 47 centers (ANZCPR: 9; PERForm: 38). We report average usage (categorical data) or median values (continuous data) at the center-level, along with the minimum and maximum across centers. Three thousand five hundred sixty-two patients were identified in the ANZCPR and 8,450 in PERForm. Substantial variation in equipment usage and CPB management practices existed (within and across registries). Open venous reservoirs were commonly used across both registries (nearly 100%), as were "all-but-cannula" biopassive surface coatings (>90%), whereas roller pumps were more commonly used in ANZCPR (ANZCPR: 85% vs. PERForm: 64%). ANZCPR participants had 640 mL absolute higher net prime volumes, attributed in part to higher total prime volume (1,462 mL vs. 1,217 mL) and lower adoption of retrograde autologous priming (20% vs. 81%). ANZCPR participants had higher nadir hematocrit on CPB (27 vs. 25). Minimal absolute differences existed in exposure to high arterial outflow temperatures (36.6°C vs. 37.0°C). We report substantial center and registry differences in both the type of equipment used and CPB management strategies. These findings suggest that the term "conventional bypass" may not adequately reflect real-world experiences. Instead of using this term, authors should provide key details of the CPB practices used in their patients.

Clinical evaluation of emboli removal by integrated versus non-integrated arterial filters in new generation oxygenators.

OBJECTIVE: To compare the emboli filtration efficiency of five integrated or non-integrated oxygenator-filter combinations in cardiopulmonary bypass circuits. METHODS: Fifty-one adult patients underwent surgery using a circuit with an integrated filtration oxygenator or non-integrated oxygenator with a separate 20 µm arterial line filter (Sorin Dideco Avant D903 + Pall AL20 (n=12), Sorin Inspire 6 M + Pall AL20 (n=10), Sorin Inspire 6M F (n=9), Terumo FX25 (n=10), Medtronic Fusion (n=10)). The Emboli Detection and Classification quantifier was used to count emboli upstream and downstream of the primary filter throughout cardiopulmonary bypass. The primary outcome measure was to compare the devices in respect of the median proportion of emboli removed. RESULTS: One device (Sorin Inspire 6 M + Pall AL20) exhibited a significantly greater median percentage reduction (96.77%, IQR=95.48 - 98.45) in total emboli counts compared to all other devices tested (p=0.0062 - 0.0002). In comparisons between the other units, they all removed a greater percentage of emboli than one device (Medtronic Fusion), but there were no other significant differences. CONCLUSION: The new generation Sorin Inspire 6 M, with a stand-alone 20 µm arterial filter, appeared most efficient at removing incoming emboli from the circuit. No firm conclusions can be drawn about the relative efficacy of emboli removal by units categorised by class (integrated vs non-integrated); however, the stand-alone 20 µm arterial filter presently sets a contemporary standard against which other configurations of equipment can be judged.

Vacuum assist: angel or demon CON.

Vacuum-assisted venous drainage (VAVD) to enhance venous return during cardiopulmonary bypass (CPB) was described as early as 1958 but was not widely used until the late 1990s. VAVD was initially used to facilitate the use of smaller cannulas with ministernotomy but was increasingly used to allow reduction in CPB circuit size while maintaining CPB flow rates. This innovation was made without planned consideration to CPB circuit design, most critically that of the venous reservoir. Clinical reports of prime reduction facilitated by VAVD in both adult and pediatric CPB were associated with reduced nadir hematocrit and rates of transfusion that encouraged the proliferation of VAVD in CPB. Concomitantly, investigators have reported both in vitro and in vivo significantly increased arterial emboli associated with the use of VAVD, mostly related to accelerated venous air entrainment. In vitro studies continue to confirm this association and likely underestimate the resulting embolic load as a result of flawed study design. While the evidence for VAVD is equivocal, our understanding of the clinical impact of gaseous microemboli in CPB is similarly limited, most likely confined to blood-brain barrier disruption. It is only after two decades that CPB component design is receiving serious attention in terms of air handling. The ethics of innovation in the field of CPB warrant careful consideration. The application of VAVD is not without consequence.

Developing a benchmarking process in perfusion: a report of the Perfusion Downunder Collaboration.

Improving and understanding clinical practice is an appropriate goal for the perfusion community. The Perfusion Downunder Collaboration has established a multi-center perfusion focused database aimed at achieving these goals through the development of quantitative quality indicators for clinical improvement through benchmarking. Data were collected using the Perfusion Downunder Collaboration database from procedures performed in eight Australian and New Zealand cardiac centers between March 2007 and February 2011. At the Perfusion Downunder Meeting in 2010, it was agreed by consensus, to report quality indicators (QI) for glucose level, arterial outlet temperature, and pCOz management during cardiopulmonary bypass. The values chosen for each QI were: blood glucose > or =4 mmol/L and < or =10 mmol/L; arterial outlet temperature < or = 37 degrees C; and arterial blood gas pCO2 > or =35 and < or =45 mmHg. The QI data were used to derive benchmarks using the Achievable Benchmark of Care (ABC) methodology to identify the incidence of QIs at the best performing centers. Five thousand four hundred and sixty-five procedures were evaluated to derive QI and benchmark data. The incidence of the blood glucose QI ranged from 37-96% of procedures, with a benchmark value of 90%. The arterial outlet temperature QI occurred in 16-98% of procedures with the benchmark of 94%; while the arterial pCO2 QI occurred in 21-91%, with the benchmark value of 80%. We have derived QIs and benchmark calculations for the management of several key aspects of cardiopulmonary bypass to provide a platform for improving the quality of perfusion practice.

Microemboli in our bypass circuits: a contemporary audit.

Cardiopulmonary bypass (CPB) may introduce microemboli into the patient's arterial circulation. These may arise from the CPB circuit. Most relevant studies have been performed in vitro; there are relatively few clinical studies. We used the Emboli Detection and Classification quantifier (EDAC) (Luna Innovations, Roanoke, VA) in a prospective clinical audit of emboli in a contemporary CPB circuit. Following ethics approval, standard clinical CPB circuits in patients undergoing CPB were instrumented with three EDAC system probes placed on the venous line, outlet of the hard-shell venous reservoir (HSVR), and distal to the arterial line filter. This was synchronized with the perfusion data management system and emboli number and volume were recorded at 30-second intervals. Recorded observations and combined data from both the EDAC and data management system were analyzed. We report data from the first 12 patients (24.5 hours of CPB) of a larger series currently being performed. The mean total emboli count per minute was significantly greater downstream of the HSVR than in the venous line and significantly less downstream of the arterial line filter than either of the above. The total count downstream of both the HSVR and the arterial line filter was greater when the vent pump was on vs. off. Despite the significant increase in emboli count downstream of the reservoir during vent operation there was a significant reduction in the total volume of emboli in this position compared with the venous line. This was further reduced by the arterial line filter. Nevertheless, the total embolic volume was greater downstream of the HSVR and the arterial filter with the vent on vs. off. The two overwhelming sources of emboli emanating from our CPB circuit were the use of the left ventricular vent and air entrained from the venous line. Such audit enables refinement of CPB management and potential component redesign which may make CPB safer and improve patient outcome.

Australian and New Zealand perfusion survey: management and procedure.

In this report, we will discuss management and procedural aspects of perfusion practice. This report allows us to compare and contrast recent trends and changes in perfusion with historic practices. A survey comprised of 233 single-answer and 12 open-ended questions was sent by e-mail to senior perfusionists or individuals in charge of perfusion in 40 hospital groups. The survey encompasses a review of the perfusion practices for the calendar year of 2003, and respondents were required to answer the survey based on the predominant practice in their institutions. Standard management of routine adult cardiopulmonary bypass (CPB) in 2003 consisted of perfusion strategies that achieved a target temperature of 32.0 degrees C (range, 28.0-35.0 degrees C), a flow index of 2.4 L/min/m2 (range, 1.6-3.0 L/min/m2) during normothermia and 1.8 L/min/m2 (range, 1.2-3.0 L/min/m2) during hypothermia, and a pressure during CPB between 50 (range, 30-65 mmHg) and 70 mmHg (range, 60-95 mmHg). Myocardial protection with blood cardioplegia was used in 77% of the 20,688 CPB cases, whereas in 53% cases, cardiotomy blood was never processed. Pre-operatively, 76% of perfusion groups assessed their patients (21% directly with the patient), and 85% responded that perfusionists performed or participated in a formal pre-bypass checklist. The majority of the perfusion groups used a handwritten perfusion record (62%), 12% used an electronic perfusion record, and 26% used both, whereas more than one half of the groups were involved in quality assurance (79%), incident reporting (74%), audits (62%), research (53%), participating in interdisciplinary meetings (53%), and morbidity and mortality meetings (65%). Only 26% conducted formal perfusion team meetings. This report outlines the status of clinical management and procedural performance for perfusion practices in Australia and New Zealand in 2003. Awareness of these trends will allow perfusionists to assess both individual practices and unit performance.

Predictive Capacity of Oxygen Delivery During Cardiopulmonary Bypass on Acute Kidney Injury.

BACKGROUND: The randomized goal-directed perfusion trial confirmed retrospective findings that a goal-directed perfusion strategy to maintain oxygen delivery index (DO2i) during cardiopulmonary bypass greater than 280 mL/min/m2 reduces the incidence of acute kidney injury (AKI). We developed a predictive model for AKI using data from the Australian and New Zealand Collaborative Perfusion Registry to determine whether these findings could be validated in a real-world clinical setting and to identify an optimal DO2i threshold for predictive diagnostic accuracy. METHODS: Data in 19,410 cardiopulmonary bypass procedures were randomly divided into training (n = 9705) and validation (n = 9705) datasets. Multivariate logistic regression was used to determine the best predictive models for AKI (RIFLE [renal Risk, Injury, Failure, Loss of renal function and End-stage renal disease] classification), incremental predictive value of minimum cardiopulmonary bypass DO2i, and optimal threshold. RESULTS: Minimum DO2i was significantly associated with any AKI, AKI risk, and AKI injury or greater class in both datasets (validation dataset; any AKI odds ratio [OR], 0.993; 95% confidence interval [CI], 0.991-0.995; P < .001; AKI risk OR, 0.994; 95% CI, 0.992-0.996; P < .001, AKI injury or greater 0.993; 95% CI, 0.991-0.996; P < .001), representing on average a 7% increase in the likelihood of AKI for every 10-mL/min/m2 decrease in DO2i. Diagnostic accuracy was similar for both datasets, with an optimal DO2i threshold of 270 mL/min/m2. The odds of any AKI were increased by 52% in those below the threshold (OR, 1.52; 95% CI, 1.29-1.77; P < .001). CONCLUSIONS: This study confirms previous findings that minimum DO2i during cardiopulmonary bypass is independently associated with AKI, supporting previous findings in a broader-risk, multicenter cohort.

The Perfusion Downunder collaborative database project.

The Perfusion Downunder Collaboration provides research infrastructure and support to the Australian and New Zealand perfusion community, with the objective of determining best practices and producing relevant research publications. The Perfusion Downunder Collaborative Database (PDUCD) has been created for the purpose of collecting a dataset for cardiopulmonary bypass (CPB) procedures that includes integration with commercially available CPB data collection software. Initial testing of the PDUCD involved collection of data from four Australian and New Zealand hospitals from March to July 2007. Data from 513 procedures were compared with the concurrent Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) database report to assess the validity of the collected data. Demographic, preoperative, and procedural variables were comparable between databases. Perfusion variables showed a median nasopharyngeal temperature of 36.7degrees C at separation from CPB (range, 35.3-37.5 degrees C), which was similar to maximum nasopharyngeal temperature (median, 36.8 degrees C). Median arterial flow and mean arterial pressure were 4.2 L/min and 57.2 mmHg, respectively. Control charts indicate a central tendency of 12.5 minutes for mean arterial pressure < 50 mmHg and 3.5 minutes for arterial flow < 1.6 L/min/m2 (cumulative time). There was no difference in median minimum and maximum blood glucose between diabetic and nondiabetic patients during CPB with 40% of patients receiving insulin. Median minimum and maximum activated clotting time (ACT) during CPB was 581 and 692 seconds, respectively. Outcome data for isolated coronary artery bypass grafting were similar for mortality (only) (both 1.8%). Initial data collection showed concurrent validity compared with the ASCTS database. The inclusion of a large quantity of calculated CPB variables in the dataset highlights the benefits of electronic data collection as a research tool within a collaborative research network and the potential for the evaluation of the relationships between patient risk factors, perfusion practice, and patient outcomes.

Australian and New Zealand perfusion survey: equipment and monitoring.

The current practice of perfusion in Australia and New Zealand continues to adopt new techniques and procedures into clinical practice. Our aims were to report current practice in 2003 and to compare and contrast current practice with historic practice. A total of 62 centers (40 perfusion groups) performing procedures using cardiopulmonary bypass (CPB) were identified and were e-mailed a detailed electronic survey. The survey was comprised of an excel worksheet that contained 233 single answer questions (either dropdown lists, yes/no, true/false, or numeric) and 12 questions that allowed the respondent to provide a commentary. Respondents were instructed to answer all questions based on what represented the predominant practice of perfusion in their institutions during 2003. We report an 89% response rate representing a caseload of 20,688 adult cases. These data allowed us to profile the following. A standard adult CPB setup in 2003 consisted of a membrane oxygenator (100% of cases), a roller pump (70%) as the main arterial pump, although a centrifugal pump would be considered for selected procedures (30%), a circuit incorporating a hard-shell venous reservoir (86%), and a mixture of biocompatible and non-biocompatible circuit components (66%). The circuit would include a pre-bypass filter (88%), an arterial line filter (94%), and would allow monitoring of the following: hard-shell venous reservoir low level (100%) with servo-regulation of the arterial pump (85%), microbubble alarm (94%) with servo-regulation of the arterial pump (79.5%), arterial line pressures (100%) with servo-regulation of the arterial pump (79%), inline venous O2 saturation (100%), and inline hematocrit (58%). Perfusion practice in Australia and New Zealand has adopted changes over the last decade; however, some areas of practice show wide variation. This survey provides a baseline of contemporary practice for Australian and New Zealand perfusionists.

Cardiopulmonary bypass in pregnancy: possible new role for the intra-aortic balloon pump.

Cardiopulmonary bypass (CPB) during pregnancy is associated with a maternal mortality similar to the nonpregnant population; however, fetal morbidity and mortality are high. Various strategies to improve fetal survival have been advocated. Alteration in uterine artery flow velocity has been reported during nonpulsatile CPB; however, roller pump-generated pulsatile flow for CPB remains controversial. We report use of the intra-aortic balloon pump (IABP) in two cases of pregnancy. In the first, the IABP was inserted after termination of a long bypass, specifically in an attempt to improve uterine perfusion and thereby relieve a profound fetal bradycardia. In the second, the IABP was used electively to provide pulsatile flow during the bypass period primarily to benefit fetal hemodynamics.

Vacuum-assisted venous drainage: to air or not to air, that is the question. Has the bubble burst?

Assisted venous drainage is a recent development in cardiopulmonary bypass (CPB) and was introduced to overcome limitations in achieving adequate blood flow through small diameter cannulas used in minimally invasive surgery. The more common application, vacuum assisted venous drainage (VAVD) is now widely used in both adult and pediatric CPB. During a clinical investigation into pharmacological cerebral protection at Green Lane Hospital, we repeatedly observed evidence of emboli in the right common carotid artery following both entrainment of air into the venous line, and also, reductions in the blood level of the hard-shell venous reservior. We subsequently embarked upon a series of in vitro experiments designed to identify sources of emboli from the CPB circuit, and to evaluate the ability of CPB circuit components to remove air entrained into the venous line under conditions of both gravity and vacuum assisted venous drainage. Initial experiments revealed design features of certain hard-shell venous reservoirs that generated gaseous emboli. In further studies using adult circuits, entrainment of air into the venous line under conditions of conventional gravity venous drainage resulted in emboli distal to the arterial filter. When these studies were repeated using VAVD, arterial line emboli increased eight to tenfold. Initial experiments with a pediatric circuit showed similar findings. Cerebral emboli during CPB have been positively correlated with increasing neurocognitive deficits. The application of VAVD has been employed clinically without any significant redesign of the components of the CPB circuit. While VAVD may be efficacious in certain scenarios, a thorough understanding of its influence on CPB is essential. Advantages must be balanced against potential hazards. The safe use of VAVD necessitates refinement of perfusion techniques, judicious choice of application, and further development of the CPB circuit.

Cerebral protection by lidocaine during cardiac operations: a follow-up study.

BACKGROUND: A previous study showed less postoperative neurocognitive impairment in open-chamber cardiac surgery patients given lidocaine for 48 hours after induction of anesthesia. In the present study, we aimed to test the benefit of a 12-hour infusion in a broader group of cardiac surgery patients, including those undergoing coronary artery bypass graft surgery. METHODS: This was a randomized, double-blind, intention-to-treat trial. Before cardiac surgery, 158 patients completed 7 neurocognitive tests and a self-rating scale for memory. They received a 12-hour infusion of either lidocaine in a standard antiarrhythmic dose or placebo, beginning at induction of anesthesia. The cognitive tests and memory scale were repeated at postoperative weeks 10 and 25. A deficit in any cognitive test was defined as a decline in score by more than or equal to the preoperative group standard deviation. RESULTS: All tests were completed by 118 and 107 patients at 10 and 25 weeks, respectively. The proportions of patients in the lidocaine and placebo groups exhibiting a deficit in one or more tests were as follows: 45.8% versus 40.7% at 10 weeks, and 35.2% versus 37.7% at 25 weeks (not significant). There were no significant differences between groups in self-ratings of memory function or length of intensive care unit or hospital stay. CONCLUSIONS: Lidocaine was not neuroprotective. The result of the previous trial may represent a type 1 error. Alternatively, benefit may be more likely for open-chamber surgery patients exposed to larger numbers of emboli or with a longer lidocaine infusion.