Postoperative pulmonary atelectasis.

The astounding number of surgical operations performed by physicians today has resulted in a greater awareness of atelectasis, a common postoperative pulmonary complication. Although easily recognized and prevented, atelectasis is frequently overlooked, resulting in serious pulmonary impairmment and occasionally surgical mortality. The word, atelectasis, is derived from the Greek, " atel-ectasis, " which denotes incomplete expansion. Although originally used to describe the non-expanded lung observed in stillborn babies,' it is now more specifically defined as an airless state of the lung parenchyma resulting from an obstruction of the tributaries serving the lung and a subsequent absorption of the entrapped air by the circulating blood.' That this condition occurs following surgery was first observed by Pasteur in l910.. In 1925, Lee and Jackson4 first demonstrated by bronchoscopy a complete bronchial obstruction by thick, tenacious secretions in a postoper-ative atelectatic patient. How frequently postoperative atelectasis occurs has been found to be dependent upon factors such as: pre-and postoperative therapy, type of surgery, and age, sex, and health of the patient. it is more often encountered after upper abdominal or time-consuming operations, in patients who smoke, have respiratory infections, or are aged, and during seasons of increased acute respiratory infections.' According to Dripps and Deming6 and Thor#{233}n7 there is a higher incidence of atelectasis in men. DeWeese,8 on the other hand, believes atelec-tasis to be twice as common in women because of their thoracic rather than abdominal type of respiration. Because of the use of grossly divergent diagnostic procedures, surgical techniques, and selection of patients by the various investigators, incidence rates ranging from 5 to 47 per cent have been reported in the literature. Thus it may well be sufficient to state that the incidence of postoperative atelecta.sis is high, and that this clinical condition represents from 90 to 94 per cent of all postoperative pulmonary complications.7 The primary cause of atelectasis is at present a controversial subject focused upon three proposed possibilities. First, it is believed by most of the recent investigators, that atelectasis is primarily the result of broncho-occlusion by secretions of the respiratory tract which are normally evacuated by the cilia, the cough mechanism , and the expulsive force of respiration. If these secretions should accumulate in the respiratory tract and plug a bronchus, aeration of the involved lung segment would be impaired, and the entrapped air would thus cause collapse of the lung. Second, atelectasis may be the result …