Acoustic energy determines haemoglobin release from erythrocytes by extracorporeal shock waves in vitro

Haemoglobin release from erythrocytes by extracorporeal shock waves from an electrohydraulic lithotripter was quantified and correlated with the acoustic energy administered to the cell container. Cells were exposed in 2-, 5.9-, and 10.5-mL vials to 100 shock waves delivered at a low, medium and high lithotripter output setting, both with and without covering of the central ellipsoidal axis by a metal cage. Using the identical set-up, previous experiments had shown that the fragmentation efficiency was linearly correlated with the delivered acoustic energy. As a result, shock waves generated from 0.83 microgram mJ-1 (in 2-mL vials) to 1.53 micrograms mJ-1 (in 10.5-mL vials) haemoglobin. At all vial types, the amount of haemoglobin correlated linearly with the delivered acoustic energy (r = 0.96 in 2-mL, r = 0.97 in 5.9-mL and r = 0.98 in 10.5-mL vials). It was independent of the presence of the cage.