INVOS™ Technology

INVOS™ system technology gives you a non-invasive “window” to the body’s microvasculature; a direct and dynamic site of gas exchange that transports about half the body’s blood volume. Measuring blood oxygenation in the microvasculature results in sensitive and site-specific insights on perfusion adequacy or – with multi-sensor monitoring – perfusion distribution across the brain and body.

Unlike parameters that measure only venous or arterial blood, INVOS™ technology includes contributions from both in a 3:1 ratio, yielding a venous-weighted percent saturation. This provides real-time data about the balance or imbalance of oxygen supply and demand, thus reflecting venous oxygen reserve - the oxygen remaining after extraction by tissues and vital organs. Decreases in venous oxygen reserve can be a warning of developing pathology and deteriorating patient condition. Published adult data has shown that an rSO₂ of 50 or a 20% decline from baseline are cause for concern and intervention, and an rSO₂ of 40 or a 25% decline from baseline are associated with neurologic dysfunction and other adverse outcomes.([FOOTNOTE=Edmonds HL, Jr Ganzel BL, Austin EH 3rd. Cerebral oximetry for cardiac and vascular surgery. Semin Cardiothorac Vasc Anesth. 2004;8(2):147-166.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Alexander HC, Kronenefeld MA, Dance GR. Reduced postoperative length of stay may result from using cerebral oximetry monitoring to guide treatment. Ann Thorac Surg. 2002;73:373-C.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Cho H, Nemoto EM, Yonas H, Balzer J, Sclabassi RJ. Cerebral monitoring by means of oximetry and somatosensory evoked potentials during carotid endarterectomy. J Neurosurg. 1998;89(4):533-538.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Iglesias I, Murkin JM, Bainbridge D, Adams S. Monitoring oxygen saturation significantly decreases postoperative length of stay: a prospective randomised blinded study. Heart Surg Forum. 2003;6:204.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Edmonds HL Jr, Singer I, Sehic A, Strickland TJ. Multimodality neuromonitoring for neurocardiology. J Interv Cardiol. 1998;11(3):197-204.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Yao FSF, Tseng CC, Woo D, Huang SW, Levin SK. Maintaining cerebral oxygen saturation during cardiac surgery decreased neurological complications. Anesthesiology. 2001;95:A152.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Roberts KW, Crnkowic AP, Linnerman IJ. Near infrared spectroscopy detects critical cerebral hypoxia during carotid endarterectomy in awake patients. Anesthesiology. 1998;89(3A):A934.],[ANCHOR=],[LINK=)^,([FOOTNOTE=Higami T, Kozawa S, Asada T, et al. Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction.Ann Thorac Surg. 1999;67(4):1091-1096.],[ANCHOR=],[LINK=])^,([FOOTNOTE=Singer I, Dawn B, Edmonds Jr. H, Stickland TJ. Syncope is predicted by neuromonitoring in patients with ICDs. PACE. 1999;22(1):216-222.],[ANCHOR=],[LINK=])

The INVOS™ system utilises near-infrared light at wavelengths that are absorbed by haemoglobin (730 and 810 nm). Light travels from the sensor’s light emitting diode to either a proximal or distal detector, permitting separate data processing of shallow and deep optical signals. INVOS™ system’s ability to localise the area of measurement, called spatial resolution, has been empirically validated in human subjects.([FOOTNOTE=Hongo K, Kobayashi S, Okudera H, Hokama M, Nakagawa F. Noninvasive cerebral optical spectroscopy. Depth-resolved measurements of cerebral haemodynamics using indocyanine green. Neurol Res. 1995;17(2):89-93.],[ANCHOR=],[LINK=]) Data from the scalp and surface tissue are subtracted and suppressed, reflecting rSO₂ in deeper tissues. This same concept applies to somatic monitoring.

The result is continuous, real-time adequacy of perfusion data in up to four sites of your choice.