Cell salvage volume and hemostatic changes in cardiac surgery: A retrospective cohort study using routine coagulation and viscoelastic assessment

Intraoperative cell salvage (CS) reduces allogeneic transfusion in cardiac surgery, but the washing process removes coagulation factors and platelets, raising hemostatic concerns. The dose-response relationship between CS volume and perioperative hemostatic changes remains poorly characterized.

In this retrospective study of adult patients undergoing cardiac surgery with CS use, two cohorts with paired hemostatic measurements were identified: a routine coagulation cohort (primary analysis) and a viscoelastic cohort (exploratory analysis). Both cohorts were restricted to patients without coagulation-affecting blood products between measurements. Multivariable linear regression examined CS volume and absolute changes in each parameter, adjusted for surgical and patient characteristics and baseline values.

In the routine coagulation cohort (N = 677; median CS 0.5 L, range 0.1-1.6 L), CS volume was not significantly associated with absolute changes in any parameter (all p ≥ 0.144). In the viscoelastic cohort (N = 50; median CS 0.8 L, range 0.2-3.7 L), CS volume was significantly associated with decreased functional fibrinogen clot strength (CFF MA: β = -3.31 mm/L; 95% CI: -5.53, -1.08; p = 0.004) and overall clot strength (CK MA: β = -2.93 mm/L; 95% CI: -5.73, -0.13; p = 0.041); after Holm correction for multiple testing, the CFF MA association remained significant (adjusted p = 0.031), whereas the CK MA association did not (adjusted p = 0.244).

At observed reinfusion volumes, CS was not associated with changes in routine coagulation parameters, but in the exploratory viscoelastic cohort, higher CS volume was associated with lower functional fibrinogen clot strength. These findings highlight the potential value of viscoelastic monitoring when higher volumes are anticipated.