[Visual identification of Doppler sounds in gas embolisms]

The method of choice for the early detection of air metabolism during neurosurgical operations in a sitting position is that of continuous cardiac auscultation using Doppler effect ultrasound apparatus. In the present study, involving 15 patients, an air embolism was produced by the injection of 2 ml of CO2 into the right heart and acoustic changes were recorded on paper using a photographic process. These optical changes, although variable, were invariably present and characteristic of aire emboli and represent an additional element in early diagnosis.