Perfusion Measures and Outcomes (PERForm) registry: First annual report.

BACKGROUND: The Perfusion Measures and Outcomes (PERForm) registry was established in 2010 to advance cardiopulmonary bypass (CPB) practices and outcomes. The registry is maintained through the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative and is the official registry of the American Society of Extracorporeal Technology. METHODS: This first annual PERForm registry report summarizes patient characteristics as well as CPB-related practice patterns in adult (≥18 years of age) patients between 2019 and 2022 from 42 participating hospitals. Data from PERForm are probabilistically matched to institutional surgical registry data. Trends in myocardial protection, glucose, anticoagulation, temperature, anemia (hematocrit), and fluid management are summarized. Additionally, trends in equipment (hardware/disposables) utilization and employed patient safety practices are reported. RESULTS: A total of 40,777 adult patients undergoing CPB were matched to institutional surgical registry data from 42 hospitals. Among these patients, 54.9% underwent a CABG procedure, 71.6% were male, and the median (IQR) age was 66.0 [58.0, 73.0] years. Overall, 33.1% of the CPB procedures utilized a roller pump for the arterial pump device, and a perfusion checklist was employed 99.6% of the time. The use of conventional ultrafiltration decreased over the study period (2019 vs. 2022; 27.1% vs. 24.9%) while the median (IQR) last hematocrit on CPB has remained stable [27.0 (24.0, 30.0) vs. 27.0 (24.0, 30.0)]. Pump sucker termination before protamine administration increased over the study period: (54.8% vs. 75.9%). CONCLUSION: Few robust clinical registries exist to collect data regarding the practice of CPB. Although data submitted to the PERForm registry demonstrate overall compliance with published perfusion evidence-based guidelines, noted opportunities to advance patient safety and outcomes remain.

Effect of geography on the use of ultrafiltration during cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Ultrafiltration (UF) is a common practice during cardiopulmonary bypass (CPB) where it is used as a blood management strategy to reduce red blood cell (RBC) transfusion, minimize adverse effects of hemodilution, and reduce proinflammatory mediators. However, its clinical utilization has been shown to vary throughout the continents. PURPOSE: The purpose of this investigation was to assess the distribution of UF use across the United States. DATA COLLECTION: Data on UF use during cardiac surgery was obtained from a national (United States) perfusion database for adult cardiac procedures performed from January 2016 through December 2018. STUDY SAMPLE: Four geographical regions were established: Northeast (NE), South (SO), Midwest (MW) and West (WE). The primary endpoint was the use of UF with secondary endpoints UF volume, CPB and anesthesia asanguineous volumes, intraoperative allogeneic RBC transfusion, nadir hematocrit and urine output (UO). 92,859 adult cardiac cases from 191 hospitals were reviewed. RESULTS: The NE and the WE had similar usages of UF (59.9% and 59.7% respectively), which were higher than the MW and the SO (38.6% and 34.9%, p < .001). When UF was utilized, the median [IQR] volume removed was highest in the NE (1900 [1200-2800]mL), and similar in all other regions (WE 1500 [850-2400 mL, MW 1500 [900-2300]mL and SO 1500 [950-2200]mL, p < .001. Median total UO was lowest in the NE 400 [210,650]mL vs all other regions (p < .001), and remained so when indexed by patient weight and operative time (NE-0.8 [0.5, 1.3]mL/kg/hour, MW-1.1 [0.7, 1.8] mL/kg/hour, SO-1.3 [0.8, 2.0]mL/kg/hour, WE-1.1 [0.7, 1.3]mL/kg/hour, p < .001. Intraoperative RBC transfusion rate was highest in the SO (21.3%) and WE (20.5%), while similar rates seen in the NE (16.2%) and MW (17.6%), p < .001. CONCLUSIONS: Across the United States there is geographic variation on the use of UF. Further research is warranted to investigate why these practice variations exist and to better understand and determine their reasons for use.

Establishment of a national quality improvement process on oxygen delivery index during cardiopulmonary bypass.

Targeted oxygen delivery during cardiopulmonary bypass (CPB) has received significant attention due to its influence on patient outcomes, especially in mitigating acute kidney injury. While it has gained popularity in select institutions, there remains a gap in establishing it globally across multiple centers. The purpose of this investigation was to describe the development of a quality improvement process of targeted oxygen delivery during CPB across hospitals throughout the United States. A systematic approach to utilize oxygen delivery index (DO2i) as a key performance indicator within hospitals serviced by a national provider of perfusion services. The process included a review of the current literature on DO2i, which yielded a target nadir value (272 mL/min/m2) and an area under the curve (DO2i272AUC) cut off of 632. All data is displayed on a dashboard with results categorized across multiple levels from system-wide to individual clinician performance. From January 2020 through December 2022, DO2i data from 91 hospitals and 11,165 coronary artery bypass graft procedures were collected. During this period the monthly proportion of DO2i measurements above the target nadir DO2i272 ranged from 60.5% to 78.4% with a mean+/-SD of 70.8 +/- 4.2%. Binary logistic regression for the first 7 months following monthly DO2i performance reporting has shown a statistically significant positive linear trend in the probability of achieving the target DO2i272 (p < .001), with a crude increase of approximately 7.8% for DO2i272AUC, and a 73.8% success rate (p < .001). A survey was sent to all individuals measuring oxygen delivery during CPB to assess why a target DO2i272 could not be reached. The two most common responses were an 'inability to improve CPB flow rates' and 'restrictive allogeneic red blood cell transfusion policies'. This study demonstrates that targeting a minimum level of oxygen delivery can serve as a key performance indicator during CPB using a structured quality improvement process.

The Role of Race on Acute Kidney Injury After Cardiac Surgery.

BACKGROUND: Acute kidney injury (AKI) frequently complicates cardiac surgery and is more common among Black patients. We evaluated determinants of race-based differences in AKI rates. METHODS: Serum creatinine-based criteria were used to identify adult cardiac surgical patients having postoperative AKI in the Perfusion Measures and Outcomes (PERForm) Registry (July 1, 2014, to June 30, 2019). Patient characteristics, operative details, and outcomes were compared by race (Black vs White) after excluding patients with preoperative dialysis, missing preoperative or postoperative creatinine, or other races. A mixed effects model (adjusting for demographics, comorbidities, surgical factors) used hospital as a random effect to predict postoperative stage 2 or 3 AKI. Propensity score analyses were conducted to evaluate robustness of the primary analyses. RESULTS: The study cohort included 34 520 patients (8% Black). More Black patients than White patients were female (43% vs 27%, P < .001), and had hypertension (93% vs 87%, P < .001) and diabetes mellitus (51% vs 41%, P < .001). Acute kidney injury of stage 2 or greater occurred in 1697 patients (5%), more often among Black than White patients (8% vs 5%, P < .001). Intraoperatively, Black patients had lower nadir hematocrits (23 vs 26, P < .001), and were more likely to be given transfusions (22% vs 14%, P < .001). After adjustment, Black race (compared with White) independently predicted odds for postoperative AKI (adjusted odds ratio 1.50; 95% confidence interval, 1.26 to 1.78). The multivariable findings were similar in propensity score analyses. CONCLUSIONS: Despite accounting for differences in risk factors and intraoperative practices, Black patients had a 50% increased odds for having moderate-severe postoperative AKI compared with White patients. Additional evaluations are warranted to identify potential targets to address racial disparities in AKI outcomes.

Effect of sex on nadir hematocrit and rates of acute kidney injury in coronary artery bypass.

OBJECTIVE: Findings from a large multicenter experience showed that sex influenced the relationship between low nadir hematocrit and increased risk of acute kidney injury after cardiac surgery. We explored whether sex-related differences persisted among patients undergoing isolated coronary artery bypass grafting. METHODS: We undertook a prospective, observational study of 17,363 patients without dialysis (13,137 male: 75.7%; 4226 female: 24.3%) undergoing isolated coronary artery bypass grafting between 2011 and 2016 across 41 institutions in the Perfusion Measures and Outcomes registry. Odds ratios between nadir hematocrit and stage 2 or 3 acute kidney injury were calculated, and the interaction of sex with nadir hematocrit was tested. The multivariable, generalized, linear mixed-effect model adjusted for preoperative and intraoperative factors and institution. RESULTS: Median nadir hematocrit was 22% among women and 27% among men (P < .001). Women were administered a greater median net prime volume indexed to body surface area (407 vs 363 mL/m2) and more red blood cell transfusions (55.5% vs 24.3%; both P < .001). Acute kidney injury was higher among women (6.0% vs 4.3%, P < .001). There was no effect of sex on the relationship between nadir hematocrit and acute kidney injury (P = .67). Low nadir hematocrit was inversely associated with acute kidney injury (adjusted odds ratios per 1-unit increase in nadir hematocrit 0.96; 95% confidence interval, 0.93-0.98); this effect was similar across sexes and independent of red blood cell transfusions. CONCLUSIONS: We found no sex-related differences in the effect of nadir hematocrit on acute kidney injury after isolated coronary artery bypass grafting. However, the strong inverse relationship between anemia and acute kidney injury across sexes suggests the importance of reducing exposure to low nadir hematocrit.

Colloid Oncotic Pressure, Monitoring its Effects in Cardiac Surgery.

Hemodilution is a common perioperative practice. The deleterious effects of excessive hemodilution and subsequent edema formation have been well documented by numerous authors. Colloid oncotic pressure (COP) is a reliable clinical indicator of hemodilution in cardiac surgery. The intent of this study is to determine if a correlation exists between COP and various patient outcome variables. It would also be helpful to know if there is a particular COP value to avoid preventing or limiting patient morbidity. Blood samples from 61 adult patients (mean age = 70 years old) undergoing cardiopulmonary bypass surgery were collected for COP calculation and comparison. Sample collection was performed before heparinization, during cardiopulmonary bypass, at the conclusion of cardiopulmonary bypass, and in the intensive care unit. The resultant values obtained were used to generate a calculated COP. The lowest sustained COP was then compared with various patient outcome variables such as fluid balance, post-operative weight gain, post-operative blood loss, extubation time, length of stay, and blood products administered. A statistically significant difference (p < .05) was found between the COP and each of the monitored continuous variables. The data also suggest that maintaining a patient's COP at or above 15 mmHg could be desirable. Frequent monitoring of a patient's COP can provide a potential benefit to clinical decision making.

Nadir Hematocrit on Bypass and Rates of Acute Kidney Injury: Does Sex Matter?

BACKGROUND: Reports have associated nadir hematocrit (Hct) on cardiopulmonary bypass with the occurrence of renal dysfunction. Recent literature has suggested that women, although more often exposed to lower nadir Hct, have a lower risk of postoperative renal dysfunction. We assessed whether this relationship held across a large multicenter registry. METHODS: We undertook a prospective, observational study of 15,221 nondialysis-dependent patients (10,376 male, 68.2%; 4,845 female, 31.8%) undergoing cardiac surgery between 2010 and 2014 across 26 institutions in Michigan. We calculated crude and adjusted OR between nadir Hct during cardiopulmonary bypass and stage 2 or 3 acute kidney injury (AKI), and tested the interaction of sex and nadir Hct. The predicted probability of AKI was plotted separately for men and women. RESULTS: Nadir Hct less than 21% occurred among 16.6% of patients, although less commonly among men (9.5%) than women (31.9%; p < 0.001). Acute kidney injury occurred among 2.7% of patients, with small absolute differences between men and women (2.6% versus 3.0%, p = 0.20). There was a significant interaction between sex and nadir Hct (p = 0.009). The effect of nadir Hct on AKI was stronger among male patients (adjusted odds ratio per 1 unit decrease in nadir Hct 1.10, 95% confidence interval: 1.05 to 1.13) than female patients (adjusted odds ratio 1.01, 95% CI: 0.96, 1.06). CONCLUSIONS: Lower nadir Hct was associated with an increased risk of AKI, and the effect appears to be stronger among men than women. Understanding of the mechanism underlying this association remains uncertain, although these results suggest the need to limit exposure to lower nadir Hct, especially for male patients.