Resident Physician Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, Beijing, China (People's Republic)
Background/Case Studies: The exploration of cell salvage for postoperative shed mediastinal blood remains inadequate. This study assessed the quality and safety of salvaged shed mediastinal blood after cardiovascular surgery.
Study
Design/Methods: This preclinical in vitro study involved patients who underwent cardiovascular surgery and experienced postoperative shed mediastinal blood over 500 ml within 6 hours. Shed mediastinal blood samples were divided into three groups based on collection times: 6, 8, and 12 hours, and underwent a washed cell salvage process. The salvaged blood from each group was assessed for quality, including hematologic performance (hemoglobin and hematocrit levels), metabolic properties (pH, lactate, and potassium levels), safety (hemolysis, bacterial contamination, and inflammatory cytokine levels such as IL-6, IL-10 and TNF-α), and erythrocyte function, which encompasses oxygen-carrying capacity (measured by 2,3-diphosphoglycerate [2,3-DPG] and adenosine triphosphate [ATP] levels), hemorheology (deformability), and morphological characteristics.
Results/Findings: Between June and September 2024, a total of 60 mediastinal blood samples were evenly distributed among the 6H, 8H, and 12H groups. The salvaged blood exhibited acceptable quality, with hematocrit (55.95% [44.98-60.40]) and hemoglobin (189.00 [160.25-200.50] g/L) within optimal ranges, near-normal pH (7.30 [7.25-7.34]), and low K⁺ levels (1.08 [0.87-1.25] mmol/L). Safety assessments revealed minimal hemolysis (free hemoglobin: 0.14% [0.10-0.21]) and inflammatory cytokines (IL-2/IL-6/IL-8/IL-10/TNF-α) within normal physiological ranges. Bacterial contamination was detected in three samples: two from the 8H group (Staphylococcus epidermidis and Corynebacterium afermentans) and one from the 12H group (S. epidermidis), while the 6H group exhibited no contamination. Erythrocyte function demonstrated preserved deformability (0.79 [0.69-0.90]) and oxygen-carrying capacity (2,3-DPG: 0.032 [0.014-0.15] µg/mL; ATP: 0.23 [0.13-0.39] µg/mL). Morphologically, erythrocytes from the 6H and 8H groups retained their characteristic biconcave-discoid shape, whereas those from the 12H group predominantly exhibited significant spiny deformation (Figure). All groups maintained quality, safety, and erythrocyte function within near-normal and safe ranges. The 6H group achieved optimal outcomes with no bacterial contamination, while the 8H and 12H groups exhibited marginally less favorable profiles in comparative metrics.
Conclusions: Our findings suggest that salvaged shed mediastinal blood collected within 6–12 hours post-surgery maintains acceptable quality and safety, with stable erythrocyte deformability and oxygen-carrying capacity. Early processing is recommended to improve the safety of salvaged blood.
