Duration of cerebral desaturation time during single-lung ventilation correlates with mini mental state examination score.

PURPOSE

Single-lung ventilation (SLV) is thought to reduce regional cerebral oxygen saturation (rSO(2)). In this study, we evaluated changes in rSO(2) during SLV and their correlation with perioperative changes in cognitive function.

METHODS

Sixty-nine patients participated in this study, each of whom received combined thoracic epidural and general anesthesia. rSO(2) was measured using INVOS 5100 (Somanetics, Troy, MI, USA) before anesthesia (baseline value) and until SLV was completed. Patient cognitive function was assessed using the mini mental state examination (MMSE) on the day before surgery (baseline) and then repeated 4 days after surgery. The patients were classified into two groups: with (desaturation group, group D) and without (nondesaturation group, group N) cerebral desaturation during SLV. Cerebral desaturation was defined as a reduction of rSO(2) during SLV less than 80% of the baseline value. An intergroup comparison was made between perioperative cognitive function findings (MMSE score change between baseline and 4th day after surgery). We also examined the correlation between the duration of desaturation during SLV and perioperative MMSE score changes in group D patients.

RESULTS

Seventeen patients were included in group D. The MMSE score decrease was significantly higher in group D as compared to that in group N (P < 0.05). The duration of desaturation time was significantly negatively correlated with MMSE score change (r(2) = 0.444, P < 0.05).

CONCLUSION

Duration of cerebral desaturation time during SLV correlates with MMSE score. Additional studies are needed to determine whether intervention against cerebral desaturation during SLV can prevent postoperative cognitive dysfunction.