Pulmonary embolism

Abstract

The incidence of pulmonary embolism in an Oxford hospital population has been studied over the period 1952-61, inclusive. The entire in-patient population of the Radcliffe Infirmary and Churchill Hospital has been examined with the exception of patients admitted to the maternity department. Throughout the period under review there was a pronounced rise in the number of patients diagnosed as suffering from pulmonary embolism, the number in the last year being approximately five times that in the first year. The total number for the 10-year period was 853. Approximately one-half of the recorded cases of pulmonary embolism throughout the entire period were fatal, so that there were about four times as many deaths in the last year as in the first. Although some of the increase in recorded cases may be artificial and represent improved diagnosis, we think it probable that the main reason for the rise in the number of recorded cases is a true increase in the frequency of pulmonary embolism. A particular point is the sharp increase of fatal cases, because the great majority of all patients dying in the Radcliffe Infirmary and Churchill Hospital are examined after death, the figure being more than 95 % in every year except one of the period under review. On the basis of information yielded by the National Hospital In-Patient Enquiry (H.I.P.E.) it has been possible to calculate age-specific rates for the incidence of pulmonary embolism in surgical and medical patients respectively for the second five-year period of the study. Sex has little influence on the liability to pulmonary embolism. Age has a pronounced influence, and the incidence increases steadily after the age of 50. Medical cases are more liable than surgical cases to suffer from pulmonary embolism in each age-group. The patients dying from pulmonary embolism have been divided into “inevitable” deaths and “potentially preventable” deaths. The increase in potentially preventable deaths has not been so steep as the increase in total deaths, and this relatively slower rate of increase may represent a partial success of anticoagulant therapy. With the exclusion of patients who died so quickly that institution of anticoagulant therapy was impracticable, the patients who received anticoagulant therapy had a much lower chance of dying than those not so treated. Although the data are inferior to those obtained in a formal therapeutic trial, they support the idea that anticoagulant therapy is highly beneficial in venous thrombosis. The various measures which have been employed to treat pulmonary embolism, both prophylactically and after its actual occurrence, are briefly discussed. The factors leading to pulmonary embolism are likewise discussed and the possibility is raised that the mouinting incidence of pulmonary embolism in hospital is one aspect of an epidemic of thrombotic disease at present affecting Western society. © 1963, British Medical Journal Publishing Group. All rights reserved.