The Bartlett-Edwards incentive spirometer: a preliminary assessment of its use in the prevention of atelectasis after cardio-pulmonary bypass.

A preliminary assessment of the effectiveness of the Bartlett-Edwards incentive spirometer was made using it as part of the post-operative treatment of 34 patients after open-heart surgery. Its effects on atelectasis were assessed by measuring vital capacity, arterial oxygen tensions, clinical signs and radiological changes. It was found that vital capacity fell after surgery to 41.5 per cent of the pre-operative level, but this rose after the use of the incentive spirometer by an average of 15.5 per cent. Arterial oxygen tensions were unaltered by the use of the incentive spirometer. Temperature, pulse and respirations were of little help in the early diagnosis of atelectasis, but all patients who were still pyrexic four days after operation showed radiological evidence of atelectasis. The incidence of atelectasis demonstrated radiologically was total 84 per cent and plate 69 per cent, sub-segmental 34 per cent and segmental 9 per cent. The implications of these findings are discussed.