Transfusion Use and Hemoglobin Levels by Blood Conservation Method Post Cardiopulmonary Bypass

Ann Thorac Surg. 2020 Apr 11. Online ahead of print

Although Online-MUF does not appear to reduce blood transfusion, larger prospective randomized controlled studies are required for confirmation.

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Background

Guidelines recommend modified ultrafiltration (MUF) and cell washing for blood conservation post cardiopulmonary bypass (CPB), although information regarding outcomes is lacking. This research compared Online-MUF (ultrafiltration of the patient’s entire circulating volume) to Offline-MUF (ultrafiltration of the residual CPB-volume) and centrifugation (cell washing of the residual CPB-volume).

Methods

This prospective cohort study enrolled 99 consecutive patients, grouped by method (Group I = Online-MUF, n = 35; Group II, Offline-MUF, n = 30; Group III, centrifugation, n = 34). Primary outcome was transfusion by 18-hours. Secondary outcomes were 18-hour hemoglobin levels, fluid balance (weight change), and biomarker levels indicating coagulation and organ function.

Results

By 18-hours, 22.9%, 6.7% and 14.7% of Group I, II, and III patients had been transfused, respectively (p = 0.19). Percentage weight gain differed by group (Group I: 5.7%, Group II: 1.3%, Group III: 4.5%; p < 0.0001). Baseline-to-18-hour hemoglobin change also differed by group, with Group I’s increase significantly exceeding that of Group II (p = 0.002) but not differing from Group III (p = 0.36). After adjustment for EuroSCORE, weight gain, and transfusion, only the Group II/III difference remained significant (p = 0.002).

Conclusions

Online-MUF does not appear to offer a reduction in blood transfusion over other methods. Although Online-MUF patients have greater improvement in baseline-to-18-hour hemoglobin compared to Offline-MUF patients, this benefit appears attributable to fluid shifting. Offline-MUF was associated with least frequent transfusions. Although Online-MUF does not appear to reduce blood transfusion, larger prospective randomized controlled studies are required for confirmation.