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 observational CABG/AVR case study shows how the INVOS^® System serves as a "first alert" as the patient's cerebral oxygen levels could not be maintained above 75% of baseline at a blood pressure <60 mmHg systolic. The patient was placed back on cardiopulmonary bypass (CPB) in order to optimize drug therapy before being weaned off again. The area under the curve (AUC), indicated in the chart by the red and orange colored areas, is formulated by calculating the desaturation below 75% of baseline times cumulative minutes. High AUC has been associated with negative outcomes. This graph demonstrates the AUC at various points during the procedure.

This case demonstrates the utility of rSO₂ as an indicator of severe ventricular dysfunction. The surgeon had completed the case and left the room while the assistant closed the skin. The perfusionist then watched the rSO₂ drop appreciably from 50 to 18 in 13 minutes. Though rSO₂ values were declining, all other vital signs were normal. Shortly afterwards, the patient's blood pressure dropped similarly and the surgeon was called back into the room. The patient went back on CPB and the surgeon discovered the right ventricle had failed. The care team believed the patient suffered a massive infarct and attempted to repair the right ventricle.

This patient consented for repair of mitral valve regurgitation (MVR) using a minimally invasive technique with port access. Just after intubation, the cerebral oximetry rSO₂ trend slowly desaturated. The anesthesiologist intervened by reducing ventilation rate and volume, allowing the carbon dioxide (CO₂) blood levels to rise thus producing cerebral vasodilation which increased blood flow to the brain. Later, when the ventilator was manipulated, the endotracheal tube dislodged out of the airway rendering no gas exchange to the patient. Cerebral oximetry rSO₂ plummeted. This urgent ventilation/perfusion mismatch was resolved by initiating CPB, establishing mechanically-controlled oxygenation and cardiac output. Interventions continued including increasing fraction of inspired oxygen (FiO₂), anesthetic depth and reduction in ventilation. Repair of the mitral valve was uneventful until the aortic occlusion balloon broke. In this case, the INVOS^® Systems' rSO₂ data assisted in assessing the effect of hemodynamic impairment on cerebral oxygen levels and indicating recovery during these critical episodes and interventions.

This patient's preoperative baselines began with lower than normal rSO₂ values, which necessitated vigilance from the beginning with aggressive and multiple interventions. Once the patient was intubated, anesthetic depth was increased and ventilation decreased, allowing the cerebral metabolic rate to decrease and PaCO₂ to rise resulting in an upward rSO₂ trend. However, when cardiopulmonary bypass (CPB) was initiated, the left cerebral rSO₂ value dropped, plummeting below the critical threshold of 40. Multiple interventions were needed to attempt to raise the rSO₂ and prevent further cerebral desaturation. These interventions included vasopressors, increasing pump flow, sedation and administration of packed red blood cells. Closure of the patent ductus arteriosus (PDA) created an improved forward flow with the shunt closure, raising rSO₂ values significantly. Once off CPB, additional hemoglobin and volume with autotransfusion blood assisted in improving this patient's cerebral perfusion status.

In this case, a dramatic cerebral desaturation occurred early in the off-pump coronary artery bypass (OPCAB) procedure. This was associated with a major bleeding event resulting in a severe drop in cerebral oxygen delivery and hematocrit. Conversion to cardiopulmonary bypass (CPB) allowed the clinicians an opportunity to resuscitate the patient effectively as seen by the rise in rSO₂ values. Low oxygen delivery was managed with multiple interventions. During the resuscitation efforts on CPB, both the SvO₂ and MAP remained within normal limits. Cerebral oximetry provided a valuable indication of cerebral perfusion during critical events and interventions.