CT-ASSESSMENT OF DEPENDENT LUNG DENSITIES IN MAN DURING GENERAL-ANESTHESIA

Purpose: We aimed to describe the frequency of atelectasis occurring d uring anaesthesia, to describe the size and pattern of the atelectasis , and to standardise the method of identifying the atelectasis and cal culate its area. Material and Methods. Patients (n=109) scheduled for elective abdominal surgery were examined with CT of the thorax during anaesthesia. Results. In 95 patients (87%) dependent pulmonary densiti es were seen, interpreted as atelectasis. Two different types of atele ctasis were found - homogeneous (78%) and non-homogeneous (9%). Attenu ation values in histograms of the lung and atelectasis were studied us ing 2 methods of calculating the atelectatic area. Conclusion: On the basis of the present findings, we defined atelectasis as pulmonary dep endent densities with attenuation values of -100 to +100 HU.