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BACKGROUND
Changes in oxygenation occur during one-lung ventilation (OLV) due to intrapulmonary shunt. Although arterial oxygenation is generally adequate, there are no studies evaluating the effect of these changes on cerebral oxygenation.


METHODS
Cerebral oxygenation (rSO(2)), heart rate (HR), blood pressure (BP), oxygen saturation (SaO(2)), and end-tidal carbon dioxide (ETCO(2)) were prospectively monitored during OLV in adults. Cerebral oxygenation was monitored using near infrared spectroscopy. No clinical decisions were made based on the rSO2 value. BP and HR were the inspired oxygen concentration was adjusted as needed to maintain the SaO(2) >/= 95%.


RESULTS
The study cohort included 40 adult patients. 18,562 rSO(2) values were collected during OLV. The rSO(2) was >/= baseline at 3,593 of the 18,562 data points (19%). The rSO2 was 0-9 </= baseline in 7,053 (38%) of the readings, 10-19 </= baseline in 4,084 (22%) of the readings, and 20-29 </= baseline in 3,898 (21%) of the readings. 2,599 (14%) of the rSO(2) values were less than 75% of the baseline value. Thirteen patients (32.5%) had at least one rSO2 value that was less than 75% of the baseline. Eight patients (20%) had rSO(2) values less than 75% of baseline for >/= 25% of the duration of OLV. These patients were older (63.7 +/- 10.2 vs 54.6 +/- 9.8 years, P<0.025), weighed more (95.8 +/- 17.4 vs 82.6 +/- 14.6 kgs, P=0.038), and were more likely to be ASA III vs II (7 of 8 versus 25 of 32, relative risk 1.75) than the remainder of the cohort.


CONCLUSIONS
Significant changes in rSO2 occur during OLV for thoracic surgical procedures. Future studies are needed to determine the impact of such changes on the postoperative course of these patients.
Tobias
Joseph D
JD
Department of Anaesthesiology University of Missouri, Columbia, Missouri.
Johnson
Garry A
GA
Rehman
Saif
S
Fisher
Robert
R
Caron
Norman
N