Background and aim Femoral vein catheterization is very commonly performed while managing children with septic shock. However, the agreement between superior venal caval (ScvO2) and femoral venous oxygen saturation (SfvO2) has not been reported in children till date. Our aim was to evaluate the agreement between ScvO2 and SfvO2 values.
Methods Children with septic shock in whom femoral vein catheter was inserted before shifting to the ICU were eligible. Paired blood samples from subclavian/Internal jugular vein and femoral catheters were drawn simultaneously after initial fluid resuscitation in these children and analysed. Agreement was assessed by Bland and Altman (BA) analysis. The study was approved by IRB.
Results A total of 32 patients were enrolled. The mean ScvO2 and SfvO2 were 72.3% and 76% respectively (p < 0.001). BA analysis showed relatively poor agreement between ScvO2 and SfvO2 with mean bias of 3.6 and 95% limits of agreement of -1.95 to 9.25 (r=-0.28, p = 0.14) (Figure 1). In general, SfvO2 values were higher than ScvO2 values with 14 of the 32 children having values ≥5%. The SfvO2 had poor sensitivity (45.5%) but 100% specificity for detecting low saturations. The PPV was 100% and the NPV was 77.8%. As SfvO2 values were generally higher than ScvO2 values, we tried a higher cut-off for SfvO2 to detect low mixed venous saturations. With a SfvO2 cut off of 72%, the sensitivity and specificity were both 100%.