Progressive changes in arterial oxygenation during one-lung anaesthesia are related to the response to compression of the non-dependent lung

Abstract

Oxygenation can improve during one-lung ventilation in some patients. This improvement is partly related to a marked increase in Pa(O(2)) during compression of the non-dependent lung.

Compressing the non-dependent lung during one-lung ventilation improves arterial oxygenation, but impairs systemic oxygen delivery by decreasing cardiac output

“…Although we advocated that compression of the nondependent lung during OLV may be a potentially useful measure to treat hypoxemia in our previous study [11], the present study shows that oxygenation seems to improve with non-dependent lung compression at the expense of CO. Although the mechanisms behind the decrease in CO that accompanies non-dependent lung compression are unclear, there are three possible explanations.…”

“…The effects of the release of the lung retractor on hemodynamic parameters and arterial oxygenation were negligible in the present study. However, it should be noted that arterial oxygenation may be impaired after the release of the retractor, since our previous study showed that there was a mild drop in Pao 2 (approximately 43 mmHg on average) in 2 min after decompression of the non-dependent lung by using continuous intra-arterial blood gas monitoring [11]. Since oxygenation is affected by several factors during OLV, such as the time course of hypoxic pulmonary vasoconstriction [14], CO [15][16][17], and epidural anesthesia [18], it is very difficult to analyze the effects of the non-dependent lung compression on the gradual improvement in arterial oxygenation.…”

“…In our previous study [11], we showed that arterial oxygenation can improve during OLV in some patients undergoing esophagectomy, and that this improvement is partly related to a marked increase in arterial oxygen tension (Pao 2 ) during compression of the non-dependent lung. One of the limitations of that study was that a pulmonary catheter was not used, and thus cardiac output (CO) and oxygen delivery data were lacking, since we did not consider it ethical to insert a pulmonary catheter solely for the purpose of the study.…”

Effects of propofol vs sevoflurane on arterial oxygenation during one-lung ventilation

“…Certain surgical manoeuvres can be compared with lung compression which can improve oxygenation. 23 Our interpretation is that many factors are involved during the study period and that one can hide another (e.g. time).…”

Protective Ventilatory Approaches to One-Lung Ventilation: More than Reduction of Tidal Volume

“…The ventilation of only a single lung may be associated with lifethreatening gas exchange impairment [41,42]. In fact, OLV may be associated with a decrease of arterial oxygen saturation below 90 % in *10 % of patients [43,44]. Hypoxemia during thoracic surgery is not mainly caused by a reduced alveolar surface but much more by venous admixture resulting from residual perfusion of the nonventilated lung and from atelectasis and poorly aerated regions in the ventilated lung.…”