Measurements of blood cell counts, coagulation factors, and
blood gases
Arterial blood samples were obtained every 5 min to count blood cells
using an Erma PCE 170 haematology analyser (Erma, Tokyo, Japan).
Coagulation factors and blood gases were measured every 15 min. Hb
concentration in the blood containing HbVs could not be accurately
determined using the current analyser because liposome capsules
interfered with the spectrophotometric measurement of Hb absorbance. The
actual Hb concentrations were estimated using a previous
method17. To measure plasma antithrombin (AT) III
activity, prothrombin time (PT), and activated partial thromboplastin
time (APTT), blood samples were collected into a heparinised syringe and
centrifuged at 50,000 ×g at 4°C for 20 min to remove HbV
particles and were measured at the Sanritsu Zelcova Laboratory (Tokyo,
Japan). Plasma fibrinogen levels were measured using rabbit fibrinogen
enzyme-linked immunosorbent assay kit (LifeSpan BioSciences, Seattle,
USA). Blood gas analyses, including plasma lactate and arterial oxygen
content (CtO2) levels, were performed using an ABL 80
blood gas analyser (Radiometer, Copenhagen, Denmark).