Tissue oxygen saturation is predictive of lactate clearance in patients with circulatory shock.

Background: Tissue oxygen saturation (StO2) decrease could appear earlier than lactate alteration. However, the correlation between StO2 and lactate clearance was unknown. Methods: This was a prospective observational study. All consecutive patients with circulatory shock and lactate over 3 mmol/L were included. Based on the rule of nines, a BSA (body surface area) weighted StO2 was calculated from four sites of StO2 (masseter, deltoid, thenar and knee). The formulation was as follows: masseter StO2 × 9% + (deltoid StO2 + thenar StO2) × (18% + 27%)/ 2 + knee StO2 × 46%. Vital signs, blood lactate, arterial and central venous blood gas were measured simultaneously within 48 h of ICU admission. The predictive value of BSA-weighted StO2 on 6-hour lactate clearance > 10% since StO2 initially monitored was assessed. Results: A total of 34 patients were included, of whom 19 (55.9%) had a lactate clearance higher than 10%. The mean SOFA score was lower in cLac ≥ 10% group compared with cLac < 10% group (11 ± 3 vs. 15 ± 4, p = 0.007). Other baseline characteristics were comparable between groups. Compared to non-clearance group, StO2 in deltoid, thenar and knee were significantly higher in clearance group. The area under the receiver operating curves (AUROC) of BSA-weighted StO2 for prediction of lactate clearance (0.92, 95% CI [Confidence Interval] 0.82-1.00) was significantly higher than StO2 of masseter (0.65, 95% CI 0.45–0.84; p < 0.01), deltoid (0.77, 95% CI 0.60–0.94; p = 0.04), thenar (0.72, 95% CI 0.55–0.90; p = 0.01), and similar to knee (0.87, 0.73-1.00; p = 0.40), mean StO2 (0.85, 0.73–0.98; p = 0.09). Additionally, BSA-weighted StO2 model had continuous net reclassification improvement (NRI) over the knee StO2 and mean StO2 model (continuous NRI 48.1% and 90.2%, respectively). The AUROC of BSA-weighted StO2 was 0.91(95% CI 0.75-1.0) adjusted by mean arterial pressure and norepinephrine dose. Conclusions: Our results suggested that BSA-weighted StO2 was a strong predictor of 6-hour lactate clearance in patients with shock. [ABSTRACT FROM AUTHOR]

Copyright of BMC Anesthesiology is the property of BioMed Central and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)