Radiological Aspects of the Pulmonary Complications Resulting from Intermittent Positive Pressure Ventilation (I.P.P.V.)

Abstract

Summary The use of intermittent positive pressure ventilation is associated with a number of pulmonary complications which are of radiological importance. These complications are grouped into three categories. In the first category are cases of asthma which require resuscitation with intermittent positive pressure ventilation. These cases may develop severe air trapping which can progress to pulmonary interstitial emphysema, although the latter complication is known to develop without a respirator being used. The second category includes pulmonary oedema, and there is brief reference to the effects of oedema of the bronchial mucosa. In an appendix to the paper the possible relationship of pulmonary oedema to the body handling of salt and water when intermittent positive pressure ventilation is used is examined. The analysis of accurately recorded fluid balance data did not reveal any statistical association between the retention of sodium, potassium or water, or any combination of these three and the presence of pulmonary oedema. The third category is represented by the serious condition of obliterative pneumonitis (respirator lung syndrome). In all three categories the clinical and radiological findings and, where relevant, the pathological findings, are described. During the year 1967 it was found that of a total of 267 admissions five developed pulmonary interstitial emphysema, four during intermittent positive pressure ventilation therapy. Two died. Sixty‐nine cases (26%) developed pulmonary oedema, and in 15 cases there seemed no adequate explanation for the oedema other than factors associated with the use of a respirator. The number of cases of pulmonary oedema closely related to the use of intermittent positive pressure ventilation is considered to be higher than 15, however. Two adults and two children under 10 years of age developed fatal obliterative pneumonitis confirmed by necropsy.