These INVOS^® System graphs from real patient cases are a compelling way to see the true impact and value of cerebral/somatic monitoring. Each INVOS^® System case graph reveals the patient's regional oxygen saturation (rSO₂) values at each stage of surgery or critical care treatment, and its responses to events and interventions.

The following case graphs demonstrate how the INVOS^® System can make a positive addition to patient care. Its objective, real-time and site-specific oxygenation data helps care teams react to oxygen imbalances, potentially reducing complications, including some potentially catastrophic in scale.

This infant with septic/cardiogenic shock and severe global hypoperfusion presented with a critical deficit in rSO₂. While other vital signs stabilized after inotropes were given, seriously low rSO₂ indicated compromised tissue perfusion, thus providing new and valuable information not detected by other bedside monitoring modalities. As a result, interventions continued until rSO₂ values improved. In this case, the somatic/peri-renal rSO₂ trended 5 - 20 points greater than cerebral rSO₂ values.

Footnotes:
1. Hoffman GM, et al. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2005:12-21.
2. Petrova A and Mehta R. Pediatr Crit Care Med 2006;7:449-454.
3. Underlying data and case notes on file ISC-10007.
4. Underlying data and case notes on file ISC-10001.

This patient with Hypoplastic Left Heart Syndrome (HLHS) had cerebral and somatic (peri-renal) post operative monitoring after a Blalock-Taussig (BT) procedure, the first stage of the Norwood procedure. The day after surgery, the cerebral and somatic rSO₂ values dropped-with a 40% drop in somatic rSO₂ values. A volume bolus was administered, and a decrease in urine output was noted. Dopamine was started at 2.5 mcg/kg/min. Later in the afternoon, this infant was acutely hypotensive with large declines in peri-renal rSO₂ and additional decline in cerebral rSO₂ levels. The BT shunt had clotted.

This case study shows that the downward trend of cerebral and peri-renal rSO₂ values presents an indication of hemodynamic changes and suggests that changes are still occurring in the patient even after surgery.

Simple operative repairs such as Atrial Septal Defect (ASD) have inherent risks. This case study on a toddler with ASD is a good example. Two-channel oximetry was utilized by monitoring cerebral and right peri-renal somatic levels after induction. Both sites showed normal values and trending relationships. Declines in both cerebral and somatic regional oxygen saturations occurred during blood loss after heparinization, isolation and cannulation of the major vessels. Upon initiation of cardiopulmonary bypass (CPB), persistent severe cerebral desaturation was identified. The anesthesiologist requested the surgeon to check the cannula positions and recommended correcting the problem before continuing. After four minutes of cerebral desaturation with a normal blood pressure, the arterial cannula was slightly re-positioned. This resulted in an immediate and profound increase in cerebral oximetry rSO₂ trends.

This case clearly shows that ASD is not simple surgery and complications can and do occur. Reserving cerebral and somatic oximetry for the most complex cases may result in missed opportunities to correct complications that would otherwise be preventable with the aid of this noninvasive monitor.

Preoperative Single Ventricle Physiology

A young infant was admitted to the PICU for cardiogenic shock with no underlying diagnosis. Two-channel monitoring of cerebral and somatic (peri-renal) oximetry using the INVOS^® System showed low trending values in regional oxygen saturation. This patient had low mean arterial pressure with significant metabolic acidosis. Hypoplastic Left Heart Syndrome (HLHS), a ductal dependent lesion, was the diagnosis. Since the infant was just over a week old, the ductus was either completely closed or barely patent. Multiple interventions made for effective treatment of this patient's deficit in vital organ tissue perfusion. The patency of ductus arteriosus did improve which was accompanied by increasing peri-renal saturations. The dosage and efficacy of prostaglandins (PGE) and other interventions were associated with changes in the relationship between the cerebral and somatic oxygen trends.