Mannitol and the combination of mannitol and gelatin impair whole blood coagulation and platelet function in vitro

Objective: Mannitol 20% and succinylated gelatin 4% are routinely used in neurosurgical procedures. Aim of this in vitro study was to explore the influence of both agents on blood coagulation and platelet function.
Methods: Blood from 21 healthy volunteers was obtained and then diluted into five groups: (1) 7% dilution with mannitol, (2) 10% dilution with gelatin (3) 17% dilution with isotonic balanced electrolyte solution, (4) 17% dilution with mannitol + gelatin and (5) undiluted blood. EXTEM, FIBTEM-Test were examined by rotational thrombelastometry via ROTEM®and thrombocyte aggregometry with the ASPI, ADP and TRAP-test were performed by Multiplate®.
Results: In the EXTEM-test Clot formation time, alpha-angle and maximum clot firmness were significantly reduced by mannitol and the combination of mannitol with gelatin. Platelet function tested in the ADP-TEST was also significantly reduced with this combination.
Conclusion: In this in vitro study clinically relevant dilutions of mannitol and gelatin showed a significant inhibition of whole blood coagulation and platelet function, which could be detrimental in neurosurgical settings.