An increase in skin blood flow induced by fluid challenge is associated with an increase in oxygen consumption in patients with circulatory shock

Purpose: To investigate whether an increase in skin blood flow (SBF) after fluid challenge was associated with an increase in oxygen consumption (VO2) in patients with circulatory shock. Materials and methods: We studied 62 patients with shock who required fluid challenge. Using laser Doppler, we measured finger SBF at basal temperature (SBFBT) and after a thermal challenge test (SBFTCT), before and after a fluid challenge (500 ml of Plasmalyte (R)). In fluid responders (i.e., increase in cardiac index >= 15%), VO2 responders (VO2R) were those with a >= 15% increase in VO2. Results: Of the 62 patients, 33 were fluid responders and 16 of these were VO2R. At baseline, VO2R had lower SBFBT (21[14-52] vs 83[24-116] PU, p = 0.03) and SBFTCT (2.1[1.2-3.3] vs 4.4[2.2-5.6] PU/degrees C, p = 0.02) than VO2 non-responders (VO2NR); hemodynamic variables were not significantly different. The increase in SBFBT (Delta SBFBT) after fluid challenge was greater in VO2R than in VO2NR (141[83-174] vs 57[17-150]%, p = 0.03). Areas under the curves for baseline SBFTCT (0.83 +/- 0.07 [0.68-0.98]) and Delta SBFBT (0.90 +/- 0.05 [0.75-1.0]) to predict Delta VO2 >= 15% were higher than for other variables. Conclusion: A lower baseline SBFTCT and a greater Delta SBFBT can identify patients in whom VO2 will increase after fluid challenge, suggesting an improvement in cellular metabolism. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study aimed to investigate whether an increase in skin blood flow after fluid challenge was associated with an increase in oxygen consumption in patients with circulatory shock. Results showed that patients with increased oxygen consumption after fluid challenge had lower baseline skin blood flow and a greater increase in skin blood flow, suggesting an improvement in cellular metabolism.