The INVOS™ system provides clinicians with reliable, timely, and actionable monitoring to help avoid adverse events and improve patient care and outcomes.
Only the INVOS™ system provides the level of performance and reliability that comes with a proven history of innovation backed by an unmatched level of quality clinical data.
INVOS™ system technology gives you a noninvasive “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.1,2,3,4,5,6,7,8,9
The INVOS™ system utilizes 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.10 Data from the scalp and surface tissue are subtracted and suppressed, reflecting rSO2 in deeper tissues. This same concept applies to somatic monitoring.
The beach chair position is commonly used during orthopaedic shoulder surgery for better visualization and access to the operative site. However, elevating the patients head during procedures may lead to gravitational effects on cerebral perfusion.11,12,
Maintaining adequate cerebral perfusion during surgery is imperative to preventing cerebral ischemia and other risks associated with cerebral desaturation. Several studies have cited that the occurrence of cerebral desaturation during shoulder surgery in the beach chair position suggests the need for perioperative cerebral perfusion monitoring.13
For patients in beach chair position, ventilation strategy positively influences cerebral perfusion regardless of anaesthetic technique.12 Cerebral oximetry provides additional information along with noninvasive blood pressure and mean arterial pressure to provide a more accurate estimate of cerebral desaturation.
The INVOS™ system provides a continuous non-invasive measurement of cerebral oxygen saturation and a reliable indication of changes in cerebral perfusion. The INVOS™ system provides real-time monitoring of changes in regional oxygen saturation (rSO2) of blood in the brain or other body tissues beneath the sensor for effective oxygen monitoring in adults.14
1. Edmonds HL, Jr Ganzel BL, Austin EH 3rd. Cerebral oximetry for cardiac and vascular surgery. Semin Cardiothorac Vasc Anesth. 2004;8(2):147-166.View Abstract
2. 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.View Abstract
3. 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.View Abstract
4. 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.View Abstract
5. Edmonds HL Jr, Singer I, Sehic A, Strickland TJ. Multimodality neuromonitoring for neurocardiology. J Interv Cardiol. 1998;11(3):197-204.View Abstract
6. Yao FSF, Tseng CC, Woo D, Huang SW, Levin SK. Maintaining cerebral oxygen saturation during cardiac surgery decreased neurological complications. Anesthesiology. 2001;95:A152.View Abstract
7. Roberts KW, Crnkowic AP, Linnerman IJ. Near infrared spectroscopy detects critical cerebral hypoxia during carotid endarterectomy in awake patients. Anesthesiology. 1998;89(3A):A934.View Abstract
8. 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.View Abstract
9. Singer I, Dawn B, Edmonds Jr. H, Stickland TJ. Syncope is predicted by neuromonitoring in patients with ICDs. PACE. 1999;22(1):216-222.View Abstract
10. 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.View Abstract
11. Laflam A, Joshi B, Brady K, Yenokyan
G, Brown C, Everett A, Selnes O, McFarland E, Hogue CW. Shoulder surgery in the beach chair position is associated with diminished cerebral autoregulation but no differences in postoperative cognition or brain injury biomarker levels compared with supine positioning: the anesthesia patient safety foundation beach chair study. Anesth Analg. 2015 Jan; 120(1):176-85. Doi: 10.1213/ ANE.0000000000000455.
12. Picton P et al. Influence of ventilation strategies and anesthetic techniques on regional cerebral oximetry in the beach chair position. Anesthesiology 2015. Oct; 123(4):765-74.