Pulmonary Oxygen Exchange during Endobronchial Anesthesia

How often should we perform arterial blood gas analysis during thoracoscopic surgery?

“…In the present study, PaO 2 determined by CIBM decreased to less than 60 mmHg in 16 patients (37%), and PaO 2 remained less than 60 mmHg in 4.5 of 141.5 hours. Furthermore, the data are in agreement with previously published studies showing that clinically significant hypoxemic events occur in 30% to 40% of all patients during thoracic procedures with OLV [2,18,19]. To detect and prevent hypoxemic events, CIBM has been used successfully in selected patient groups [3,4].…”

Arterial oxygenation and one-lung anesthesia

“…Increasing alveolar ventilation using larger tidal volumes is theoretically attractive as it may also prevent small airway closure and the development of low ventilation perfusion units that result from the decrease in dependent lung volume during OLA [1]. The use of larger (15 ml/kg) [55] and smaller tidal volumes [56,57] during OLA have been linked with increases and decreases, respectively, in arterial oxygenation; however, utilizing larger tidal volumes has not universally resulted in statistically significant [4, [58][59][60] or clinically important [21,55] increases in arterial oxygenation. The reasons for this conflicting evidence include firstly that increases in lung volume lead to increases in pulmonary vascular resistance and diversion of blood flow toward the nonventilated lung [4, 21,25,[58][59][60].…”

Reducing tidal volume and increasing positive end-expiratory pressure with constant plateau pressure during one-lung ventilation: effect on oxygenation

“…10 -12 ml kg 21 ). 4 More recently, numerous authors have reported that the use of large intraoperative V T during OLV may be associated with increased postoperative respiratory failure. 5 -8 As a result, it was no longer considered safe to use high-V T volumes during OLV, and limiting plateau pressure should be a major objective in the ventilatory setting of OLV.…”