Variation in outcomes with extracorporeal membrane oxygenation in the era of coronavirus: A multicenter cohort evaluation.

Extracorporeal membrane oxygenation (ECMO) is used in critically ill patients with coronavirus disease 2019 (COVID-19) with acute respiratory distress syndrome unresponsive to other interventions. However, a COVID-19 infection may result in a differential tolerance to both medical treatment and ECMO management. The aim of this study was to compare outcomes (mortality, organ failure, circuit complications) in patients on ECMO with and without COVID-19 infection, either by venovenous (VV) or venoarterial (VA) cannulation. This is a multicenter, retrospective analysis of a national database of patients placed on ECMO between May 2020 and January 2022 within the United States. Nine-hundred thirty patients were classified as either Pulmonary (PULM, n = 206), Cardiac (CARD, n = 279) or COVID-19 (COVID, n = 445). Patients were younger in COVID groups: PULM = 48.4 ± 15.8 years versus COVID = 44.9 ± 12.3 years, p = 0.006, and CARD = 57.9 ± 15.4 versus COVID = 46.5 ± 11.8 years, p < 0.001. Total hours on ECMO were greatest for COVID patients with a median support time two-times higher for VV support (365 [101, 657] hours vs 183 [63, 361], p < 0.001), and three times longer for VA support (212 [99, 566] hours vs 70 [17, 159], p < 0.001). Mortality was highest for COVID patients for both cannulation types (VA-70% vs 51% in CARD, p = 0.041, and VV-59% vs PULM-42%, p < 0.001). For VA supported patients hepatic failure was more often seen with COVID patients, while for VV support renal failure was higher. Circuit complications were more frequent in the COVID group as compared to both CARD and PULM with significantly higher circuit change-outs, circuit thromboses and oxygenator failures. Anticoagulation with direct thrombin inhibitors was used more often in COVID compared to both CARD (31% vs 10%, p = 0.002) and PULM (43% vs 15%, p < 0.001) groups. This multicenter observational study has shown that COVID patients on ECMO had higher support times, greater hospital mortality and higher circuit complications, when compared to patients managed for either cardiac or pulmonary lesions.

A Survey of Women in the Perfusion Workforce: 2021.

A diverse and equitable working environment is desirable. In 2011, a survey was distributed to all female perfusionists in the United States. This survey suggested that the female perfusionists share the same difficulties as women in the labor force. The role of women in society in general is clearly changing. Female perfusionists have been part of that evolution. Promoting equality and respecting diversity are central to life today. A follow-up survey was distributed to evaluate the status and the change in gender stereotypes in the field of perfusion over the past 10 years. Women make up nearly half of the U.S. labor force and 35.7% of the present perfusion workforce in North America (1,077 certified women). Women make 82 cents for every dollar that men earn and this disparity widens for women with more education. The purpose of this survey was to poll women in perfusion to evaluate concerns and opinions in their careers and to compare to the 2011 survey results. In December 2021, a 39-question survey (surveymonkey.com, San Mateo, CA) was made available to all female perfusionists in North American via social media websites (Facebook.com, Perfusion.com, LinkedIn.com, Perflist, Perfmail, and FPP Listserv). There were 384 responses to the 2021 survey compared to the 538 responses in 2011. About 32.1% of the survey participants have been used in perfusion for more than 20 years; 37.6% have earned a master's degree compared to 2011, where 18.3% had master's level education; 72.5% are the financial providers for their family with 44.2% earning $101-150,000.00 and 40.3% greater than $200,000.00, which is a significant change from 2011; 61.5% consider themselves under moderate stress compared to 63.0% in 2011; 94.3% take call on a regular basis; and 74.1% feel they miss essential family functions because of their schedules. Similarly, 62.8% felt discriminated against because of gender compared to 50.9% in 2011. This survey suggests that the female perfusionists have shown to be assertive (72% are the primary financial supporter of their families) and competent in the field of cardiovascular perfusion (nearly 40% have masters degrees). Further analysis is needed to discern whether female perfusionists are treated with comparable respect as their male colleagues when 50.0% report some discrimination or harassment in their workplace.

The assessment of patients undergoing cardiac surgery for Covid-19: Complications occurring during cardiopulmonary bypass.

The outbreak of the novel coronavirus pandemic (COVID-19) has resulted in dramatic changes to the conduct of surgery both from a patient management perspective and in protecting healthcare providers. The current study reports on the status of COVID-19 infections in patients presenting for cardiac surgery with cardiopulmonary bypass (CPB) on circuit complications. A tracking process for monitoring the presence of COVID-19 in adult cardiac surgery patients was integrated into a case documentation system across United States hospitals where out-sourced perfusion services were provided. Assessment included infection status, testing technique employed, surgery status and CPB complications. Records from 5612 adult patients who underwent cardiac surgery between November 1, 2020 and January 18, 2021 from 176 hospitals were reviewed. A sub-cohort of coronary artery bypass graft patients (3283) was compared using a mixed effect binary logistic regression analysis. 4297 patients had negative test results (76.6%) while 49 (0.9%) tested positive for COVID-19, and unknown or no results were reported in 693 (12.4%) and 573 (10.2%) respectively. Coagulation complications were reported at 0.2% in the negative test results group versus 4.1% in the positive test result group (p < 0.001). Oxygenator gas exchange complications were 0.2% in the negative test results group versus 2.0% in the positive test results group (p = 0.088). Coronary artery bypass graft patients with a positive test had significantly higher risk for any CPB complication (p = 0.003) [OR 10.38, CI 2.18-49.53] then negative test patients [OR 0.01, CI 0.00-0.20]. The present study has shown that patients undergoing cardiac surgery with CPB who test positive for COVID-19 have higher CPB complication rate than those who test negative.

The Use of Extracorporeal Membrane Oxygenation in COVID-19 Patients with Severe Cardiorespiratory Failure: The Influence of Obesity on Outcomes.

Extracorporeal membrane oxygenation (ECMO) in the management of severely ill patients with COVID-19 has been reported in more than 5,827 cases worldwide according to the Extracorporeal Life Support Organization (ELSO). Several pre-existing conditions have been linked to an increase in COVID-19 mortality risk including obesity. The purpose of this research is to review the clinical experience from a cohort of 342 COVID-19 patients treated with ECMO in which 61.7% (211/342) are confirmed obese. Following institutional review board approval, we reviewed all 342 COVID-19 patients supported with ECMO between March 17, 2020 and March 18, 2021, at 40 American institutions from a multi-institutional database. Descriptive statistics comparing survivors to non-survivors were calculated using chi-square, Welch's ANOVA, and Kruskal-Wallis rank sum test as appropriate. Multivariable logistic regression was used to estimate the effect of body mass index (BMI) on the odds of survival while adjusting for age, gender, chronic renal failure, diabetes, asthma, hypertension, and pre-ECMO P/F ratio. Descriptive analysis showed that obese patients were more likely to be hypertensive (58.1% vs. 32%, p < .001), diabetic (42% vs. 30%, p < .05), and female (35% vs. 21%, p < .05), and had longer median days from intubation to cannulation (4.0 vs. 2.0, p < .05). Obese patients appeared to also have a slightly lower median age (47.9 vs. 50.5, p = .07), higher incidence of asthma (17.8% vs. 10.2%, p = .09), and a slightly lower pre-ECMO PaO2/FiO2 ratio (67.5 vs. 77.5, p = .08) though these differences were slightly less statistically reliable. Results from the logistic regression model suggest no statistically reliable association between BMI and odds of survival. Age had a moderately large and statistically reliable negative association with survival; the relative odds of survival for a 59-year-old patient were approximately half those of a 41-year-old patient (OR = .53, 95% CI: .36-.77, p < .001). Obesity does not seem to be a major risk factor for poor outcomes in COVID-19 patients supported with ECMO; however, age was moderately negatively associated with survival. The potential influence of other comorbidities on odds of survival among these patients warrant further investigation.

Zero-Balance Ultrafiltration during Cardiopulmonary Bypass Is Associated with Decreased Urine Output.

Zero-balance ultrafiltration (ZBUF) during cardiopulmonary bypass (CPB) has been purported to reduce pro-inflammatory mediators during cardiac surgery. However, its clinical benefit is equivocal and its effect on renal function unknown. The purpose of this study was to examine the effect of ZBUF on urine output in adult patients undergoing CPB. Following institutional review board approval, 98,953 records from a national registry of adult patients at 215 U.S. hospitals between January 2016 and September 2019 were reviewed. Groups were stratified according to ZBUF use. Anuric patients were excluded from the study as they were patients with missing data on urine output, ultrafiltration use, or ZBUF volume. The primary endpoint was intraoperative urine output normalized to body weight and procedure duration (total operative time). Final analysis of this endpoint was carried out using a linear mixed-effects regression model adjusting for patient and procedural characteristics, as well as practice patterns associated with surgeons and perfusionists. There was a significant 16.1% reduction in median urine output for ZBUF patients (.94 [.54, 1.47] mL/kg/h) vs. the non-ZBUF group (1.12 [.70,-1.73] mL/kg/h), p < .001. After statistically adjusting for patient and procedural characteristics, each liter of ZBUF volume was associated with an estimated change in intraoperative urine output of -.03 mL/kg/h (95% CI: [-.04 to -.02], p < .001). The median ZBUF volume was 1,550 [1,000, 2,600] mL, and when ZBUF was used, conventional ultrafiltration (CUF) was more likely to be used as well (88.4% vs. 44.8%, p < .001). ZBUF patients had median asanguineous volume and crystalloid cardioplegia nearly two times more than non-ZBUF patients, and had slightly higher red blood cell transfusions (17.6% vs. 16.3%, p < .05). The application of ZBUF during CPB was associated with patients having lower urine output and significantly higher use of CUF. Further research is required to determine if these results are reproducible in prospective clinical studies.

Application of goal-directed therapy for the use of concentrated antithrombin for heparin resistance during cardiac surgery.

The maintenance of anticoagulation in adult patients undergoing cardiopulmonary bypass is dependent upon a number of factors, including heparin concentration and adequate antithrombin activity. Inadequate anticoagulation increases the risk of thrombosis and jeopardizes both vascular and extracorporeal circuit integrity. The purpose of this study was to evaluate a goal-directed approach for the use of antithrombin in patients who were resistant to heparin. Following institutional review board approval, data were obtained from quality improvement records. A goal-directed protocol for antithrombin was established based upon heparin dosing (400 IU kg-1 body weight) and achieving an activated clotting time of ⩾500 seconds prior to cardiopulmonary bypass. Two groups of patients were identified as those receiving antithrombin and those not receiving antithrombin. Outcome measures included activated clotting time values and transfusion rates. Consecutive patients (n = 140) were included in the study with 10 (7.1%) in the antithrombin group. The average antithrombin dose was 1,029.0 ± 164.5 IU and all patients had restoration to the activated clotting time levels. Patients in the antithrombin group were on preoperative heparin therapy (80.0% vs. 24.6%, p = 0.001). Prior to cardiopulmonary bypass the activated clotting time values were lower in the antithrombin group (417.7 ± 56.1 seconds vs. 581.1 ± 169.8 seconds, p = 0.003). Antithrombin patients had a lower heparin sensitivity index (0.55 ± 0.17 vs. 1.05 ± 0.44 seconds heparin-1 IU kg-1, p = 0.001), received more total heparin (961.3 ± 158.5 IU kg-1 vs. 677.5 ± 199.0 IU kg-1, p = 0.001), more cardiopulmonary bypass heparin (22,500 ± 10,300 IU vs. 12,100 ± 13,200 IU, p = 0.016), and more protamine (5.4 ± 1.2 vs. 4.1 ± 1.1 mg kg-1, p = 0.003). The intraoperative transfusion rate was higher in the antithrombin group (70.0% vs. 35.4%, p = 0.035), but no differences were seen postoperatively. Utilization of a goal-directed algorithm for the administration of antithrombin for the treatment of heparin resistance is effective in patients undergoing cardiac surgery.

The Effect of Antifibrinolytic Use on Intraoperative Cell Salvage: Results from a National Registry of Surgical Procedures.

Intraoperative cell salvage (ICS) is a critical component of any blood management program involving surgery with a high potential for blood loss. The introduction of antifibrinolytics (AF) may reduce blood loss. The purpose of this study was to evaluate the use of AF on ICS in non-cardiac surgical procedures. Following institutional review board approval, 69,935 consecutive case records between January 2016 and September 2019 from a national registry of adult surgical patients were reviewed. Procedure types were stratified into one of nine surgical categories: general (GN, n = 1,525), neurosurgical (NS, n = 479), obstetric (OB, n = 1,563), cervical spine (CS, n = 2,701), lumbar spine (LS, n = 38,383), hip arthroplasty (HA, n = 13,327), knee arthroplasty (KA, n = 596), vascular (VA, n = 9,845), or orthopedic other (OO, n = 1,516). The primary endpoint was the use of AF with the secondary endpoints ICS shed blood volume and volume available for return. The overall use of AF across all surgical procedures increased from 21.4% in 2016 to 25.4% in 2019. The greatest increases were seen in NS (4.4% to 16.2%), LS (13.7% to 23.1%), and HA (55.8% to 61.9%). For several procedure types, there was an initial increase then either a leveling off or a decline in AF use: OB initially increased from 6.2% to 10.8% in 2018, whereas GN (9.4% to 7.2%) and VA surgery declined slightly (9.9% to 5.7%). When comparing patients who did not receive AF with those who did, there were similar volumes of ICS available for return in all groups, except for LS, GN, and VA, where lower volumes were seen in the No-AF groups. The use of AF has increased each year over the 4-year period in most of the surgical categories, but several have declined. There may be a beneficial effect of AF with lower ICS volumes available for return in a few groups.

The effect of various blood management strategies on intraoperative red blood cell transfusion in first-time coronary artery bypass graft patients.

Effective blood management during cardiac surgery requires a multifactorial effort to limit exposure to allogeneic blood products. The present study evaluated the distribution of intraoperative interventions in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Records from patients undergoing non-reoperative surgery at 120 hospitals between January 2017 and December 2017 were reviewed, and red blood cell transfusion quartiles established. The 31 hospitals with the lowest transfusion rates fell into the first quartile (low transfusion group, n = 3,186 patients), while 29 hospitals with the highest transfusion were in the fourth quartile (high transfusion group, n = 2,561). A survey was sent to assess the blood management techniques: acute normovolemic hemodilution, autologous prime, fluid management, intraoperative autotransfusion, ultrafiltration, and transfusion triggers. All data are presented as mean (standard deviation). Patients in the low transfusion group had red blood cell transfusion rate of 5.5%, while the high transfusion group was 28.3%. There was no difference in gender or age. Fluid management was reduced in the low transfusion group with smaller prime volumes and anesthesia volumes, but higher crystalloid use during cardiopulmonary bypass. The low transfusion group did not use acute normovolemic hemodilution as often and had lower sequestered volumes when used. When ultrafiltration was used, the low transfusion quartile group removed more volume (1,555.9 ± 955.2 vs. 1,326.1 ± 918.9 mL, p ⩽ 0.001). In the low transfusion group, nadir hematocrit on-cardiopulmonary bypass averaged 1.6% lower and 3.0% lower for transfusion post-cardiopulmonary bypass. Intraoperative red blood cell units averaged 0.11 ± 0.50 U in low transfusion group compared to 0.63 ± 1.14 U in the high transfusion group. Mixed-effects logistic regression identified first in operating room and first on cardiopulmonary bypass hematocrit, estimated blood volume and nadir hematocrit transfusion trigger as the strongest predictors for red blood cell transfusion. Significant variation exists in the transfusion of red blood cell in coronary artery bypass graft patients undergoing cardiopulmonary bypass which may be related to the application of intraoperative blood management techniques.

The Effect of Standardizing Autologous Prime Techniques in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass.

Autologous priming (AP) of the extracorporeal circuit has been used as a technique to reduce iatrogenic anemia in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). The purpose of this study was to review the results of standardizing AP techniques to reduce variation among clinicians and its effect on clinical outcomes. Standardized goal-directed protocols for AP were established by the cardiac team and applied to all adult cardiac surgical patients where CPB was used. Following Institutional Review Board approval, data were analyzed for two sequential groups of patients: Non-standardized AP (NST-AP) and standardized AP (ST-AP). Exclusion criteria included pre-CPB hemodynamic instability and preoperative hematocrit (Hct) values less than 30%. The primary end point was the transfusion of red blood cells (RBCs), whereas secondary end points included Hct change and other perioperative allogeneic blood product transfusions. Data are presented as mean and SD. Of the 192 patients evaluated, 82 were in the NST-AP group and 110 in the ST-AP group. There were no preoperative demographic differences across groups. Total AP volume was lower in the NST-AP group than in the ST-AP patients (486.8 ± 259.6 mL vs. 1,048.2 ± 218.7 mL, p < .001). Whereas pre-CPB Hct values were identical between the groups, the first on-CPB (25.7% ± 4.5% vs. 27.9% ± 4.2%, p < .001), high CPB (27.7% ± 3.5% vs. 29.1% ± 3.6%, p < .008), and first postoperative (32.5% ± 4.0% vs. 34.3% ± 3.9%, p < .003) were all significantly higher in ST-AP patients. Perioperative transfusion rate was higher in NST-AP patients (63.6%) vs. ST-AP (44.6%), p < .01. There was no difference in intraoperative RBC transfusion, but postoperatively, more patients in the NST-AP group received RBCs than those in the ST-AP group (51.2% vs. 28.2%, p < .01). The application of an ST-AP protocol was effective in reducing hemodilution, which was associated within higher Hcts and lower postoperative transfusion rates.

Gender and intraoperative blood transfusion: analysis of 54,122 non-reoperative coronary revascularization procedures.

BACKGROUND: Previous studies have shown that women undergoing isolated coronary artery bypass graft (CABG) surgery have an increased risk for postoperative morbidity and mortality when compared to men. Additionally, recent evidence suggests that blood transfusions are independently associated with an increased risk of adverse outcome. METHODS: We evaluated gender differences in the risk of intraoperative red blood cell (RBC) transfusion during CABG surgery. Consecutive, non-reoperative CABG procedures performed across 196 institutions between April 2012 and May 2015 were retrospectively reviewed. Gender differences for intraoperative transfusion were evaluated with a multi-variable binary logistic regression model, adjusting for age, blood volume (Nadler formula to normalize for height and weight), body mass index, procedure acuity, net extracorporeal circuit prime volume, use of autologous priming, first hematocrit (Hct) in the operating room (OR), nadir Hct on cardiopulmonary bypass (CPB), volume added on CPB, ultrafiltration volume, urine output on CPB and procedure duration. RESULTS: Among 54,122 patients (25.3% female), 21.6% (n = 11,701) received a RBC transfusion. Compared to men, female patients were older (66 years vs. 64 years, p<0.001), had lower blood volumes (4.3L vs. 5.6L, p<0.001) and a lower preoperative Hct (32.9% vs. 37.2%, p<0.001). Transfusion rates were three-fold higher in women versus men (45.1% vs. 13.7%, p<0.001). After adjustment for independent predictors of intraoperative transfusion, women remained at increased risk versus men (OR = 1.30, 95%CI = 1.19-1.43). CONCLUSIONS: Women have an increased risk of intraoperative RBC transfusion versus men. After adjusting for height and weight, much of this risk is due to gender differences in preoperative Hct and blood volume; however, a residual significant risk remained after adjustment. Perfusion strategies aimed at gender differences may minimize unnecessary transfusions. Future study on the impact of gender on transfusion practice in cardiac surgery is warranted.

The influence of ultrafiltration on red blood cell transfusion during cardiopulmonary bypass.

BACKGROUND: Ultrafiltration during cardiopulmonary bypass (CPB) reduces fluid overload and inflammatory mediators in open-heart surgery and is thought to reduce the risk of red blood cell (RBC) transfusion. We evaluated its effectiveness in reducing RBC transfusions in a large population undergoing cardiac surgery, among patients in general as well as by gender. METHODS: We analyzed 40,650 propensity-matched adult cardiac surgery cases conducted over a 61-month period at 195 hospitals. We assessed the risk of intraoperative transfusion (⩾1 unit RBC) according to body surface area (BSA)-normalized ultrafiltration volume via mixed-effects binary logistic regression. Our statistical model controlled for 12 demographic and operative variables as well as for center level tendencies in ultrafiltration use and intraoperative RBC transfusion. In light of recent findings on gender and risk of transfusion, we also included an interaction effect between gender and ultrafiltration volume (UV). RESULTS: Ultrafiltration was associated with an increased crude rate of RBC transfusion (32.1% vs. 28.1%, p<0.001), but equivalent crude median hematocrit change from first in operating room to nadir on bypass (-11% in both groups, p = 0.133). After controlling for patient, operative and site-level characteristics, we found no statistically significant effect on transfusion rate by volume of ultrafiltrate removed nor did we find statistical support for any gender-specific effect of ultrafiltration. CONCLUSIONS: Ultrafiltration is not associated with a reduction of risk of RBC transfusion during cardiac surgery. The use of ultrafiltration as a method for reducing intraoperative RBC transfusion warrants further study.

Does the Type of Cardioplegia Solution Affect Intraoperative Glucose Levels? A Propensity-Matched Analysis.

Myocardial protection during cardiac surgery is a multifaceted process that is structured to limit injury and preserve function. Evolving techniques use solutions with varying constituents that enter the systemic circulation and alter intrinsic systemic concentrations. This study compared two distinct cardioplegia solutions on affecting intraoperative glucose levels. Data were abstracted from a multi-institutional perfusion registry, including a total of 1,188 propensity-matched cases performed from January through October 2016, at 17 cardiac surgical centers across the United States in which both del Nido and 4:1 cardioplegia were used during the study period. Covariate data included insulin administration, crystalloid cardioplegia volume, diabetes history, glucose at operating room entry, and nine additional variables. Primary and secondary endpoints were the highest intraoperative glucose level and maximum glucose in excess of 180 mg/dL. Mixed-effects multivariable linear and logistic regression models were used to assess the primary and secondary endpoints, respectively, allowing for statistical control of center and surgeon effects. Greater median crystalloid cardioplegia volume was given in the del Nido group (n = 594) 1,040 mL [interquartile range (IQR) = {800, 1,339}] compared with the 4:1 group (n = 594) 466 mL [IQR = {360, 660}] in the 4:1 group (p < .001) despite these groups being statistically indistinguishable in terms of bypass and cross-clamp times as well as seven other patient covariates. More patients required intraoperative insulin drip in the 4:1 group compared with del Nido (65.7% vs. 56.2%, p < .001). Multivariable linear mixed-effects analysis yielded an estimated maximum intraoperative glucose for the del Nido group of 177.8 mg/dL compared with that of the 4:1 group, 183.5 mg/dL-a statistically significant reduction of 5.7 mg/dL (p = .03). Multivariable logistic mixed-effects analysis showed a statistically nonsignificant reduction in the likelihood of crossing the 180 mg/dL threshold for del Nido compared with 4:1 (odds ratio [OR] = .79, p = .214). After controlling for known confounding variables, intraoperative maximum glucose levels for the del Nido group were 5.7 mg/dL lower than that of the 4:1 group; there was limited evidence suggesting a difference between methods in the likelihood of exceeding the threshold of 180 mg/dL intraoperatively. Further research is warranted to examine the differential effects of cardioplegia solution on intraoperative glucose levels.

Does the type of cardioplegia used during valve surgery influence operative nadir hematocrit and transfusion requirements?

INTRODUCTION: Myocardial protection is performed using diverse cardioplegic (CP) solutions with various combinations of chemical and blood constituents. Newer CP formulations that extend ischemic intervals may require greater asanguineous volume, contributing to hemodilution. METHODS: We evaluated intraoperative hemodilution and red blood cell (RBC) transfusion rates among three common CP solutions during cardiac valve surgery. Data from 5,830 adult cardiac primary valve procedures where either four-to-one blood CP (4:1), del Nido solution (DN) or microplegia (MP) was used at 173 United States surgical centers. The primary outcome was the nadir hematocrit (Hct) during cardiopulmonary bypass (CPB), with a secondary outcome of total units of RBC transfused intraoperatively. Outcomes were assessed using mixed-effects regression, with controls for patient size, age, first Hct in the operating room, ultrafiltration volume, net bypass circuit priming volume, anesthesia and perfusion asanguineous volumes, cross-clamp and total procedure times, procedure type, reoperation, hospital, surgeon and twelve other patient and procedural variables. RESULTS: A total of 2,641 patients received 4:1 (45.3%), 1,864 received DN (32.0%) and 1,325 received MP (22.7%). There were only slight differences in the central tendency (mean (SD)) for crude nadir Hct on CPB: 4:1, 25.5 (4.5), DN, 26.0 (4.6) and MP, 26.5 (4.7). After controlling for numerous operative and patient characteristics, the regression-adjusted estimate of the nadir Hct on CPB for MP was 26.2%, compared to 25.7% for 4:1 and 25.7% for DN; differences between MP and the other methods were statistically significant (p<0.01). Unadjusted mean RBC units transfused per patient was very similar across the groups (4:1, 2.2; MP, 2.3; DN, 2.4). Regression-adjusted estimates for the number of units of RBC transfused intraoperatively showed no statistically significant differences between CP methods. CONCLUSIONS: In patients undergoing cardiac valve surgery, the type of CP did not have a strong clinical impact on hemodilution or transfusion. Choice of a myocardial preservation solution can be made independently of its effect on intraoperative Hct.

Does the Type of Cardioplegic Technique Influence Hemodilution and Transfusion Requirements in Adult Patients Undergoing Cardiac Surgery?

During cardiac surgery, myocardial protection is performed using diverse cardioplegic (CP) solutions with and without the presence of blood. New CP formulations extend ischemic intervals but use high-volume, crystalloid-based solutions. The present study evaluated four commonly used CP solutions and their effect on hemodilution during cardiopulmonary bypass (CPB). Records from 16,670 adult patients undergoing cardiac surgery with CPB between February 2016 and January 2017 were reviewed. Patients were classified into one of four groups according to CP type: 4-1 blood to crystalloid (4:1), microplegia (MP), del Nido (DN) and histidine-tryptophan-ketoglutarate (HTK). Covariate-adjusted estimates of group differences were calculated using multivariable logistic and linear mixed effects regression models. The primary end point was intraoperative transfusion of allogeneic red blood cells (RBCs), with a secondary end point of intraoperative hematocrit change. Among all patients, 8,350 (50.1%) received 4:1, 4,606 (27.6%) MP, 3,344 (20.1%) DN, and 370 (2.2%) HTK. Both 4:1 and MP were more likely to be used in patients undergoing coronary revascularization surgery, whereas DN and HTK were seen more often in patients undergoing valve surgery (p < .001). The highest volume of crystalloid CP solution was seen in the HTK group, 2,000 [1,754, 2200], whereas MP had the lowest, 50 [32, 67], p < .001. Ultrafiltration usage was as follows: HTK-84.9%. DN-83.7%, MP-40.1%, and 4:1-34.0%, p < .001. There were no statistically significant differences on the primary outcome risk of intraoperative RBC transfusion. However, statistically significant differences among all but one of the pair-wise comparisons of CP methods on hematocrit change (p < .05 or smaller), with MP having the lowest predicted drift (-7.8%) and HTK having the highest (-9.4%). During cardiac surgery, the administration of different CP formulations results in varying intraoperative hematocrit changes related to the volume of crystalloid solution administered.

The Influence of Intraoperative Autotransfusion on Postoperative Hematocrit after Cardiac Surgery: A Cross-Sectional Study.

Utilization of intraoperative autotransfusion (IAT) during cardiac surgery with cardiopulmonary bypass (CPB) has been shown to reduce allogeneic red blood cell transfusion. Previous research has emphasized the benefits of using IAT in the intraoperative period. The present study was designed to evaluate the effects of using IAT on overall hematocrit (Hct) drift between initiation of CPB and the immediate postoperative period. We reviewed 3,225 adult cardiac procedures occurring between February 2016 and January 2017 at 84 hospitals throughout the United States. Data were collected prospectively from adult patients undergoing cardiac surgery with CPB, and stored in the SpecialtyCare Operative Procedural rEgistry (SCOPE), a large quality improvement database. Patients receiving allogeneic transfusion and those with missing covariate data were excluded from analysis. The effect of IAT volume returned to patients on the primary endpoint, hematocrit change from CPB initiation to intensive care unit (ICU) entry, was assessed using a multivariable linear mixed effects regression model controlling for patient demographics, operative characteristics, surgeon, and hospital. Descriptive analysis showed greater positive hematocrit change with increasing autotransfusate volume returned. Those patients with no IAT volume returned saw a median hematocrit change of +2.00%, whereas those with more than 380 mL/m2 BSA had a median Hct drift of +5.00% (p < .001). After controlling for known confounds, our regression estimate of the effect of IAT volume returned on Hct drift was +.0045% per 1 mL/m2 BSA (p < .001). For a patient with the median autotransfusate volume returned (273 mL/m2 BSA), and all other covariate values at their respective medians, this translates to a predicted hematocrit change of +3.6% (95% CI +3.1 to +4.1). These findings lend further support to the notion that autotransfusate volume is positively associated with increases in postoperative hematocrit.

The effectiveness of acute normolvolemic hemodilution and autologous prime on intraoperative blood management during cardiac surgery.

OBJECTIVE: Intraoperative blood management during cardiac surgery is a multifaceted process incorporating various interventions directed at optimizing oxygen delivery and enhancing hemostasis. The purpose of this study was to evaluate the effects of acute normovolemic hemodilution (ANH) and autologous priming (AP) on preserving the hematocrit during cardiopulmonary bypass (CPB). METHOD: Case records from a national registry of adult patients who underwent cardiac surgery between January and October 2016 were reviewed. Groups were determined as follows: ANH, AP, ANH+AP or Neither. Primary endpoint was first the hematocrit on CPB with secondary endpoints of hematocrit drift and red blood cell (RBC) transfusion rate. RESULTS: Eighteen thousand and twenty-four (18,024) consecutive patients were reviewed. The first CPB hematocrit was lowest in the ANH group (26.5%±4.4%) and highest in ANH+AP patients (27.5%±4.8%) (p<0.001). The change in hematocrit was greatest in the ANH group (8.3%±3.9%) compared to both the AP (6.4%±3.8%) and ANH+AP (6.9%±4.1%) groups (p<0.001). Intraoperative RBC transfusions were as follows: ANH 26 (7.8%), AP 2,531 (20.0%), ANH+AP 287 (10.3%) and Neither 592 (26.7%) (p<0.001). CONCLUSIONS: Regression results show that the use of ANH will result in the greatest decline in hematocrit values. When combined with AP, higher hematocrits and lower transfusions were seen.

A BMI >35 does not protect patients undergoing cardiac bypass surgery from red blood cell transfusion.

The effect of obesity on allogeneic intraoperative blood product transfusion in patients undergoing coronary artery bypass graft surgery (CABG) is poorly understood. We analyzed the influence of obesity on the risk of intraoperative red blood cell (RBC) transfusion among 45,200 consecutive non-reoperative CABG procedures from a multi-institutional perfusion database. A body mass index (BMI) in obese I category was associated with a 9.9% decrease in transfusion risk (p<0.05). Compared to patients with a normal BMI, obese I and obese III patients do not have any change in the relative risk of RBC transfusion. Overweight and mild obesity have a protective role in reducing intraoperative blood transfusion during cardiopulmonary bypass (CPB) surgery. However, logistic regression analysis showed that much of the observed reduction in transfusion rates for obese patients can be accounted for by other known confounds. The lack of a linear effect of increasing BMI on blood transfusion risk is a novel finding and warrants further investigation.

Utility of cell salvage in women undergoing abdominal myomectomy.

OBJECTIVE: We examined the use and cost of autologous blood cell salvage in women who undergo abdominal myomectomy. STUDY DESIGN: Patients who underwent abdominal myomectomy from 2007-2011 were identified. Use of the cell salvage system and reinfusion of autologous blood in women who had the system set-up were analyzed. Cost was examined by directly reported data. RESULTS: We identified 607 patients who underwent abdominal myomectomy. Four hundred twenty-five women (70%) had the set-up of the cell salvage system. Cell-salvaged blood was processed and reinfused into 85 of these subjects (20%). In a multivariable model, performance of myomectomy by a gynecologic-specific surgeon (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.28-3.59), >5 myomas (OR, 2.49; 95% CI, 1.27-4.89), and larger uterine size statistically were associated significantly with cell-salvage device set-up. Conversely, having a reproductive-endocrinology-infertility specialist as the surgeon was associated with a significant reduction in cell-salvage system set-up (OR, 0.37; 95% CI, 0.21-0.66). For the women who had cell-salvage system set-up, uterine size of >15-19 weeks of gestation (OR, 3.22; 95% CI, 1.56-8.95) or ≥20 weeks of gestation (OR, 4.62; 95% CI, 1.45-14.73), operating time of >120 minutes (OR, 3.98; 95% CI, 1.70-9.29), and intraoperative blood loss of >1000 mL (OR, 26.31; 95% CI, 10.49-65.99) were associated significantly with a higher incidence of reinfusion of cell-salvaged blood. CONCLUSION: The routine use of cell salvage in women who undergo abdominal myomectomy does not appear to be warranted. Cell-salvage set-up appears to be cost-effective only when reinfused, but clinical characteristics cannot predict accurately which women will require reinfusion of cell-salvaged blood.