Near-Infrared Spectroscopy Cerebral and Somatic (Renal) Oxygen Saturation Correlation to Continuous Venous Oxygen Saturation via Intravenous Oximetry Catheter

PURPOSE:

Near-infrared spectroscopy (NIRS) and continuous central venous oxygen saturation (ScvO(2)) via oximetry catheter are 2 modalities available to estimate adequacy of oxygen delivery in postoperative pediatric cardiac patients. Near-infrared spectroscopy measures regional tissue oxygenation and is routinely used in pediatric cardiac surgery patients. By not requiring an invasive catheter, NIRS has the advantage over mixed venous oxygen saturation (SvO(2)) monitoring. An alternative marker of global tissue oxygenation is central venous oxygen saturation (ScvO(2)). A recently developed pediatric-sized oximetric catheter (PediaSat; Edwards Lifesciences, Irvine, CA, USA) functions as a central venous catheter and provides a continuous ScvO(2) reading, an accepted surrogate to SvO(2). To date, the correlation between NIRS and ScvO(2) has not been quantified. The aim of this study was to examine the strength of the bivariate correlation between NIRS and ScvO(2) measurements.

DESIGN/METHODS:

Twenty pediatric patients undergoing cardiac surgery had the PediaSat catheter placed with the tip in the superior vena cava and NIRS sensors (cerebral and renal) placed in the operating room per routine protocol. Hourly measurements of NIRS-cerebral (NIRS-C), NIRS-renal, and ScvO(2) readings were recorded for each patient for up to 48 hours postoperatively.

RESULTS:

A cumulative total of 630 hours of data were collected. Spearman correlation coefficients for NIRS-renal vs ScvO(2) and NIRS-C vs ScvO(2) measurements were r = 0.38 (P = .09) and r = 0.58 (P< .008), respectively.

CONCLUSIONS:

In this small cohort of pediatric patients undergoing heart surgery, there was a moderate but statistically significant correlation between the ScvO(2)-catheter and the NIRS-C values. Further studies are required to determine which oxymetric modality of monitoring cardiac output most aids in the postoperative management of these patients.