[Influence of the bone-cement mixing time on hypotonic blood circulation reactions in hip-joint replacement surgery].

The amount of methylmethacrylatemonomer that is released into the blood-stream, during the alloplastic replacement of the hip-joint, depends on the time taken to prepare the bone cement(so-called extracorporeal polymerization-time). In vitro experiments reveal that the release of monomers depends on the preparation time. Gas-chromatographic monomer determinations show, that by prolongation of the preparation time from 2 to 5 minutes, the amount of monomer released into the blood-stream is decreased by a factor of 7. With the increase in preparation time the number of hypotonic circulatory reactions caused by the monomers will decrease. Extension of the extracorporeal polymerization-time from 2 to 5 minutes decreases the incidence of intra-operative circulatory depressions from 95% to 26%. These results were obtained by intra-arterial measurements of the blood pressure in the radial artery.