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.

Expanding perfusion services through mobile point-of-care coagulation monitoring.

Current trends in cardiac surgery have challenged perfusionists to seek diversification of services. Point-of-care coagulation (POCC) monitoring represents a desirable area of perfusion service expansion. The purpose of the study was to create a series of hemostatic conditions to assess the functionality of POCC monitors to identify specific coagulopathies with identifiable profiles for algorithm development. Fresh (< 4 h) bovine blood, anticoagulated with anticoagulant citrate dextrose, was adjusted to a hematocrit of 30.0 +/- 2.0%. Hypofibrinogenemia < or = 90 mg/dL), thrombocytopenia (< or = 70,000/mm3), platelet dysfunction (850 microg/mL of nitroglycerin/mL of blood) and hyperfibrinolysis (0.40 units of urokinase/mL of blood) were created. Five POCC devices were used to evaluate activated clotting time, thrombin time, fibrinogen, platelet function, prothrombin time, activated partial thromboplastin time and thromboelastograph. Results are reported as percentage change from control for each test (abtract table). [table: see text] Each test performed showed specificity and sensitivity for certain coagulopathies, however variability amongst monitors was encountered. In conclusion, the development of a mobile cart incorporating POCC monitors with knowledge of specific coagulopathic conditions may expand perfusion service.

The effects of ultrafiltration on e-aminocaproic acid: an in vitro analysis.

Blood conservation strategies have become a standard of practice in cardiac surgery, with the use of antifibrinolytic agents and ultrafiltration two popular techniques. The purpose of this study was to evaluate the effects of continuous ultrafiltration on e-aminocaproic acid (EACA) utilizing functional coagulation analysis. A fibrinolytic assay was developed to detect EACA using the thromboelastograph (TEG) and urokinase (0.138 units 0.360 mL(-1)). Fresh bovine blood (23 +/- 1% hematocrit) was pumped (100 mL min(-1)) through an ultrafiltrator (HPH 400) at 37 degrees C with a transmembrane pressure of 280 mmHg. EACA (0.065 mg mL(-1)) was circulated for 10 minutes before initiating ultrafiltration. Samples (pre- and postultrafiltrator) were obtained at baseline, 5, and 10 min of ultrafiltration and analyzed via the fibrinolytic assay for EACA determination. TEG profiles significantly decreased from concentrations of 0.065 mg to 0.0325 mg of EACA mL(-1) blood (maximum amplitude MA, 75.4 +/- 4.0 versus 63.3 +/- 2.9, p < .05, TEG index 5.4 +/- 0.7 versus 4.0 +/- 0.3, p < .05). Fibrinolysis at 30 min increased as EACA concentrations declined (0.065 mg, 0% versus 0.032 mg, 16.4 +/- 2.8%, p < .05). During ultrafiltration the MA increased significantly from baseline to 10 min postultrafiltrator (68.2 +/- 3.0 versus 75.8 +/- 10.0, p < .05) and from 5 min pre- to 10 min postultrafiltrator (69.7 +/- 4.2 versus 75.8 +/- 10.0, p < .05). The TEG index showed no significant change, and no fibrinolysis was detected at 30 min from any datapoint during ultrafiltration. In conclusion, this study demonstrates that the antifibrinolytic properties of EACA are maintained during ultrafiltration with a 25% reduction in total circulating volume.

Effects of increasing FiO2 on venous saturation during cardiopulmonary bypass in the swine model.

Adequacy of perfusion during cardiopulmonary bypass (CPB) is dependent on nutrient delivery and waste removal from the tissue. A recent study showed that over 75% of cardiopulmonary bypass procedures are completed using continuous venous saturation (SvO2) monitoring. The purpose of this study was to determine the effect of changing FiO2concentration on SvO2. A total of eight mixed gender 45-kg swine were placed on CPB under moderate hypothermic conditions. Animals were divided evenly into two groups: Experimental, where FiO2 was increased to 100% and blood flow decreased to an SvO2 level of prechange in FiO2, and Control, where the same condition was created except no change in blood flow. Variables measured include hemodynamic, blood gas, intramyocardial pH, and lactic acid concentrations. In the experimental group, percentage change of blood flow was decreased from baseline 28.4% +/- 12.5% (p < .005) as well as percentage change of oxygen delivery 23.9% +/- 14.7% (p < .005). Systemic venous saturation percentage change was increased in both the experimental 14.4% +/- 6.8% (p < .05) and control 11.2% +/- 7.1% (p < .05) groups. Jugular venous saturation percentage change was decreased in the experimental group 7.8% +/- 6.34% (p < .02), but not in the control animals. Myocardial venous saturation percentage change decreased in the experimental group to 3.73% +/- 8.34% (p < .004). Experimental manipulation, however, did not significantly change jugular lactic acid concentrations or intramyocardial pH values. In conclusion, these results suggest that decreased blood flow adjusting for increased SvO2 associated with high PaO2 did not result in significant reduction of adequacy of perfusion markers for organs studied.