[Determination of methylmethacrylate in expired gases after hip prosthesis cementing]

Total hip replacement using methylmethacrylate can induce early intraoperative hypoxaemia caused, according to some authors, by alveolar gas dilution by acrylic monomer vapour. In order to test this hypothesis, expired monomer was measured in ten patients undergoing total hip replacement carried out under narconeuroleptanalgesia. Methylmethacrylate was collected by adsorption on activated charcoal and measured by gas chromatography. The quality of expired monomer was 25 +/- 10 micrograms after cotyloid sealing. It is of 264 +/- 396 micrograms after femoral sealing; the most important excretion took place in the first three minutes, and its total duration may exceed 18 min. A simple calculation showed quite convincingly that the volume of expired monomer vapour was not sufficient to explain the hypoxaemia: impaired arterial oxygenation associated with the use of methylmethacrylate is not due to a dilution technique.