Renal Oxygen Saturation as an Early Indicator of Shock in Children

Background: Shock is a life-threatening syndrome in which tissue perfusion and oxygen delivery are inadequate. Near-infrared spectroscopy (NIRS) has been suggested as a noninvasive tool for monitoring and detecting the state of inadequate tissue perfusion. Renal and mesenteric oximetry show decreased cardiac output earlier than systemic or global parameters of tissue oxygenation or cerebral oximetry. However, until now there has been no study on the validity of regional renal oxygen saturation (rRSO₂) by NIRS for diagnosing shock in children. Purpose: To analyze the validity of rRSO₂ by NIRS to diagnose shock in children. Patients and Methods: This cross-sectional study was conducted in critically ill children (aged 1 month–18 years) who were admitted to the pediatric intensive care unit (PICU), from September to November 2020, consecutively. Patients were classified into two groups: shock and non-shock. The diagnosis of shock is based on clinical criteria (tachycardia, sign of hypoperfusion and decrease systolic blood pressure <P5 according to age). Measurement of rRSO₂ by NIRS was performed by the doctor in charge when the patient came to PICU. The baseline rRSO₂ value (%) made a receiver operating characteristic (ROC) curve and was used to find the optimal cut-off value and calculated sensitivity and specificity. Results: We enrolled 20 critically ill patients. The baseline rRSO₂ in the shock (n=10) and non-shock (n=10) groups were, 44.00±4.95 vs 78.70±4.52 (p 0.003). The optimal cutoff value of the baseline rRSO₂ to predict shock is less than 58.5% with area under the curve (AUC) value is 94.4% (95% CI of 84.4–100%), p 0.001, sensitivity 90% and specificity 90% in critically ill children. Conclusion: The rRSO₂ value by NIRS can differentiate between shock and non-shock in critically ill patients accurately.