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

Correlation of HCT-ALB, SmtO2, CRT and LAC with renal impairment and prognosis in patients with septic shock

Background

This study investigates the correlation between the difference in hematocrit (HCT) and serum albumin (ALB) levels (HCT-ALB), muscle tissue oxygen saturation (SmtO2), capillary refill time (CRT), and blood lactate (Lac) with the severity of renal function damage and prognosis in patients with septic shock.

Methods

Conducted from February 2022 to February 2024, this study included 116 septic shock patients treated at the First Affiliated Hospital of Anhui Medical University. Patients were divided into groups based on whether they developed acute kidney injury: 40 patients were included in the acute kidney injury group, and the remaining 76 were placed in the non-kidney injury group. The levels of HCT-ALB, SmtO2, CRT, and Lac were compared between the groups. Patients were followed up to assess their 28day survival outcomes; 75 surviving patients were placed in the survival group, and 41 deceased patients were in the death group. Differences in clinical data and levels of HCTALB, SmtO2, CRT, and Lac between the two groups were analyzed to explore the relationship of these indicators with patient prognosis.

Results

Levels of HCT-ALB, CRT, and Lac were higher, while SmtO2 was lower in the acute kidney injury group compared to the non-kidney injury group (P<0.05). Similarly, the death group exhibited higher levels of HCTALB, CRT, and Lac and lower SmtO2 levels compared to the survival group (P<0.05). Univariate and multivariate analyses revealed that HCT-ALB, SmtO2, CRT, and Lac significantly impact patient survival outcomes, demonstrating high predictive value for patient mortality with respective AUC values of 0.834, 0.782, 0.903, and 0.918. The combined application of these indicators for predicting patient mortality had an AUC value of 0.985, which is higher than when the indicators were used individually.

Conclusions

HCT-ALB, SmtO2, CRT, and Lac are significantly elevated in patients with acute kidney injury and deceased patients, closely correlating with the severity and prognosis of septic shock. These indicators can serve as essential biomarkers for assessing the condition and prognosis of these patients.

Association of tissue oxygen saturation levels with skeletal muscle injury in the critically ill

This study aimed to investigate the association between the level of tissue oxygen saturation (StO2) and quadriceps/skeletal muscle dysfunction, measured using the Medical Research Council (MRC) scale and ultrasonography, in critically ill patients. Thirty-four patients hospitalized at the Critical Care Medicine Center of Kindai University Hospital, between January 2022 and March 2023, were enrolled in this study. The StO2 of the quadriceps muscle was measured via near-infrared spectroscopy. Muscle atrophy was measured by the thickness, cross-sectional area (CSA), and echo intensity of the rectus femoris (RF). These values were evaluated every alternate day until 13 days after admission or until discharge, whichever occurred first. Muscle weakness was assessed using the sum score of the MRC scale (MRC-SS), with the patient sitting at bedside. The mean age of the patients was 67.3 ± 15.3 years, and 20 (59%) were men. Seven patients (21%) were admitted for trauma, and 27 (79%) were admitted for medical emergencies or others. The mean score for the MRC-SS was 51.0 ± 7.9 points. RF thickness and CSA significantly decreased after day 7 (p < 0.05). There were no significant changes in StO2 levels during hospitalization. However, there were positive correlations between the nadir StO2 during hospitalization and MRC-SS, and changes in RF thickness and CSA at discharge (r = 0.41, p = 0.03; r = 0.37, p = 0.03; and r = 0.35, p = 0.05, respectively). StO2 in the quadriceps muscle may be useful for predicting muscle atrophy and dysfunction in patients with critical illnesses.