BMC Anesthesiology (May 2023)

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

  • Yan Chen,
  • Jin-min Peng,
  • Xiao-yun Hu,
  • Shan Li,
  • Xi-xi Wan,
  • Rui-ting Liu,
  • Chun-yao Wang,
  • Wei Jiang,
  • Run Dong,
  • Long-xiang Su,
  • Huai-wu He,
  • Yun Long,
  • Li Weng,
  • Bin Du

DOI
https://doi.org/10.1186/s12871-023-02139-4
Journal volume & issue
Vol. 23, no. 1
pp. 1 – 8

Abstract

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Abstract 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.

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