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.
Leveraging rSO2 in Upright Humerus Repair
Orthopedic surgeons have been using the "beach chair" or "barbershop" position for arthroscopy procedures since the 1980s. This upright sitting position improves access to the shoulder and reduction in brachial plexus injuries. However, episodes of cerebral hypoperfusion resulting in stroke have been documented1. In this example, treatment with nitroglycerin paste, fluid bolus and packed red blood cells kept cerebral oxygenation balanced. Continuous cerebral oximetry monitoring identified critical levels of cerebral perfusion to help avoid onset and escalation of complications during this upright procedure.
1. Cullen D, et al. J Anesth Patient Safety Foundation. 2007 Summer (22): No. 2, 25-40.
rSO2 During Acute Thrombus Formation
In this case, bilateral lower extremity monitoring with the INVOS® System revealed unexpected unilateral desaturation in the right leg after sheath placement. This prompted the surgeon to suspect acute thrombus formation. The vessel was clamped and exploration revealed a fresh thrombus below the sheath. An embolectomy was performed and when the clamp was removed, right leg extremity perfusion returned to baseline. When the left common femoral artery was clamped, there was a progressive desaturation in the left leg extremity, due to the expected but relatively short ischemic time. Note the brisk return of perfusion and hyperemic response after release of the left common femoral clamp.
Patient-Specific Responses During TAA
The surgical plan for this elderly patient with a large aneurysm in the aortic arch that extends into the descending thoracic aorta, was to utilize CPB without DHCA. Neurological monitoring included EEG, SSEP, TCD, cerebral and somatic oximetry. Two sensors were placed over the patient's spine at the mid-thoracic and distal thoracic spine positions. This case shows how a precipitous drop in cerebral rSO2 can occur at the time of clamping, potentially indicating an incomplete Circle of Willis. Immediate information from the INVOS® System allowed the surgical team to respond instantly, possibly preventing damage. Also, when deploying the endo-stent, distal blood flow can be compromised to the spine and other abdominal organ beds. In this case, rSO2 from sensors located over the spine showed little change in oxygen levels.
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