Lower abdominal surgery under isoflurane anesthesia resulted in atelectasis in 85% of patients on CT scan, which correlated with significant impairments in FVC, FEV1, and Pao2.
Observational (n=13)
Does lower abdominal surgery under isoflurane anaesthesia cause atelectasis and impair lung function in patients with healthy hearts and lungs?
Computed tomography reveals a high incidence of postoperative atelectasis that correlates with impaired lung function and oxygenation, despite normal standard pulmonary x-rays and lack of clinical pulmonary complications.
Absolute Event Rate: 85% vs 0%
Thirteen patients with healthy hearts and lungs, and with a mean age of 68 years, who were scheduled for lower abdominal surgery during isoflurane anaesthesia with muscular paralysis, were investigated with arterial blood gases, spirometry, pulmonary x-ray and computed tomography (CT) of the chest before and during anaesthesia, as well as during the first 4 postoperative days. Before anaesthesia, lung function and gas exchange were normal in all patients. Pulmonary x-ray and CT scans of the lungs were also normal. During anaesthesia, 6 of 13 patients developed atelectasis (mean 1.0% of intrathoracic transverse area in all patients). Two hours postoperatively, 11 of 13 patients had atelectasis and the mean atelectatic area was 1.8%. Pao2 was significantly reduced by 2.1 kPa to 9.8 kPa. On the first postoperative day, the mean atelectasis was unaltered (1.8%). None of the atelectasis found on CT scanning could be detected on standard pulmonary x-ray. Forced vital capacity (FVC) and forced expired volume in 1 s (FEV1) were significantly decreased to 2/3 of preoperative level. Pao2 was significantly reduced to less than 80% of the preoperative level (mean 9.4 kPa). There were significant correlations between the atelectatic area and the impairment in FVC, FEV1, and Pao2. Spirometry and blood gases improved during the succeeding postoperative days, and atelectasis decreased. No patient suffered from pulmonary complications, as judged from clinical criteria and pulmonary x-ray, in contrast to the findings of atelectasis in 85% of the patients by computed tomography.
Lindberg et al. (Sat,) conducted a observational in Lower abdominal surgery (n=13). Lower abdominal surgery under isoflurane anesthesia vs. Preoperative baseline was evaluated on Atelectasis detected by computed tomography. Lower abdominal surgery under isoflurane anesthesia resulted in atelectasis in 85% of patients on CT scan, which correlated with significant impairments in FVC, FEV1, and Pao2.