Acid Aspiration Syndrome

Sir,—I have just re-read the paper by Hester and Heath (1977) and realize that they have misquoted our work (Hutchinson and Newson, 1975). They state that mortality from pulmonary acid aspiration syndrome in all hospitals in Auckland between 1967 and 1969 was 1 in 11 000 of nonobstetric patients. In fact, 1 in 11 000 was the frequency of severe pulmonary acid aspiration syndrome in all operative cases during that 3-yr period, including obstetric patients. The mortality (which regrettably was not quoted in our paper) was 10% of the morbidity, or 1 in 110 000, before the use of magnesium trisilicate mixture. • In the 3-yr period 1970-72, when magnesium trisilicate was coming into routine use, the frequency of severe pulmonary acid aspiration syndrome in all operative cases (including obstetrics) was 1 in 40 000. The mortality was 1 in 120 000, which one must admit was not very different from the period before antacid therapy. It is interesting to note that none of our 13 patients with severe acid aspiration syndrome during the 6 years had received antacid before anaesthesia. Currently we are analysing the frequency of Mendelson's syndrome during the years 1973-78, and this should indicate if the routine administration of a magnesium trisilicate mixture before operation has been justified.