Atelectasis and lung function in the postoperative period

Abstract

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.

Postoperative muscle training improves tidal volume and vital capacity in the postoperative period of CABG surgery

“…Surgery and anesthesia affect ventilatory function. Some authors observed an increase in lung density in areas dependent on both lungs after anesthesia, suggesting formation of areas of atelectasis [11]. According to Nardi et al [12], CPB time greater than 60 minutes seems to have an inverse relationship with MIP values.…”

The effects of positive end-expiratory pressure on respiratory system mechanics and hemodynamics in postoperative cardiac surgery patients

“…It is also important to note that postoperative cardiac patients frequently may present severe hypoxemia, due to atelectasis that requires an alveolar recruitment strategy, employing high levels of PEEP. Simple bedside radiography is considered a poor method to detect postoperative atelectasis (6). Therefore, PEEP should be routinely employed in maneuvers for alveolar opening in the presence of hypoxemia.…”

“…Atelectasis and hypoxemia are the main clinical findings. Atelectasis seems to be caused by reduced lung volume and small airway collapse (5,6). Hypoxemia may reflect increased intrapulmonary shunt due to collapsed lung areas and/or altered ventilation-perfusion ratio (3).…”

Non-pharmacologic Prevention of Surgical Wound Infection

“…Concern about atelectasis is appropriate because it occurs in up to 85% of patients undergoing lower abdominal surgery and is thought by some to be an important cause of morbidity [73][74][75]. Two mechanisms contribute to perioperative atelectasis: compression and absorption.…”