Noninvasive monitoring of central venous oxygen saturation by jugular transcutaneous near-infrared spectroscopy in pediatric patients undergoing congenital cardiac surgery

Oxygen saturation in intraosseous sternal blood measured by CO-oximetry and evaluated non-invasively during hypovolaemia and hypoxia - a porcine experimental study

PURPOSE

This study intended to determine, and non-invasively evaluate, sternal intraosseous oxygen saturation (SsO₂) and study its variation during provoked hypoxia or hypovolaemia. Furthermore, the relation between SsO₂ and arterial (SaO₂) or mixed venous oxygen saturation (SvO₂) was investigated.

METHODS

Sixteen anaesthetised male pigs underwent exsanguination to a mean arterial pressure of 50 mmHg. After resuscitation and stabilisation, hypoxia was induced with hypoxic gas mixtures (air/N₂). Repeated blood samples from sternal intraosseous cannulation were compared to arterial and pulmonary artery blood samples. Reflection spectrophotometry measurements by a non-invasive sternal probe were performed continuously.

RESULTS

At baseline SaO₂ was 97.0% (IQR 0.2), SsO₂ 73.2% (IQR 19.6) and SvO₂ 52.3% (IQR 12.4). During hypovolaemia, SsO₂ and SvO₂ decreased to 58.9% (IQR 16.9) and 38.1% (IQR 12.5), respectively, p < 0.05 for both, whereas SaO₂ remained unaltered (p = 0.44). During hypoxia all saturations decreased; SaO₂ 71.5% (IQR 5.2), SsO₂ 39.0% (IQR 6.9) and SvO₂ 22.6% (IQR 11.4) (p < 0.01), respectively. For hypovolaemia, the sternal probe red/infrared absorption ratio (SQV) increased significantly from baseline (indicating a reduction in oxygen saturation) + 5.1% (IQR 7.4), p < 0.001 and for hypoxia + 19.9% (IQR 14.8), p = 0.001, respectively.

CONCLUSION

Sternal blood has an oxygen saturation suggesting a mixture of venous and arterial blood. Changes in SsO₂ relate well with changes in SvO₂ during hypovolaemia or hypoxia. Further studies on the feasibility of using non-invasive measurement of changes in SsO₂ to estimate changes in SvO₂ are warranted.

Correlation of Near-Infrared Spectroscopy Oximetry and Corresponding Venous Oxygen Saturations in Children with Congenital Heart Disease

Invasive and non-invasive monitoring allow for early detection of hemodynamic compromise, facilitating timely intervention and avoidance of further decline. While venous oximetry is useful for assessing the adequacy of systemic oxygen delivery (DO₂), it is most often intermittent, invasive, and costly. Near-infrared spectroscopy (NIRS) oximetry allows for the non-invasive estimation of the adequacy of DO₂. We assessed the correlation between cerebral NIRS oximetry and superior vena cava (SVC) and jugular venous (JV) oxygen saturations and between renal NIRS oximetry and inferior vena cava (IVC) oxygen saturations. Systematic review of the literature was conducted to identify studies with data regarding near-infrared spectroscopy and venous saturation. The PubMed, EMBASE, Medline, and Cochrane databases were queried using the following terms in isolation and various combinations: "congenital heart disease," "near infrared spectroscopy," "venous saturation," and "pediatric." Pediatric studies in which simultaneous NIRS oximetry and corresponding venous oxygen saturations were simultaneously collected after cardiac surgery or catheterization were identified. Data were pooled from these studies to analyze the correlation between NIRS oximetry and the corresponding venous oxygen saturations. A total of 16 studies with 613 patients were included in the final analyses. Data were present to compare cerebral and renal NIRS oximetry with corresponding venous oxygen saturation. Cerebral NIRS and SVC and JV oxygen saturations and renal NIRS and IVC oxygen saturations demonstrated strong degrees of correlation (r-value 0.70 for each). However, cerebral NIRS and IVC oxygen saturation had a week degree of correlation (r-value of 0.38). Pooled analyses demonstrate that cerebral NIRS oximetry correlates strongly with SVC or JV oxygen saturation while renal NIRS oximetry correlates strongly with IVC oxygen saturations. A weak correlation was noted between cerebral NIRS oximetry and IVC oxygen saturations.

Near-Infrared Spectroscopy Monitoring in Pediatric Anesthesiology: A Pro-Con Discussion

Near-infrared spectroscopy (NIRS) has been increasingly used as a non-invasive measurement of cerebral tissue oxygen saturation. The aim of this short review is to discuss the benefits and drawbacks of its use in the pediatric anesthesia population. In the context of cardiac surgery, lower intraoperative NIRS values have shown a modest association with neurodevelopmental outcomes while lower neonatal intensive care unit NIRS values have been correlated with reduced neurodevelopment in children. However, it is still unclear if management aimed at increasing cerebral tissue oxygenation would have any benefit on these outcomes. Without prospective research looking into the effects of intervention given proper thresholds, the true benefit of NIRS use is still up for debate. Even with current research gaps, its use in the clinical setting continues.