CC BY-NC-ND 4.0 · J Neuroanaesth Crit Care 2016; 03(04): S66-S69
DOI: 10.4103/2348-0548.174740
Conference Proceeding
Thieme Medical and Scientific Publishers Private Ltd.

Near-infrared spectroscopy—current status

Gyaninder P. Singh
1   Assistant Professor, Department of Neuroanaesthesiology and Critical Care, AIIMS, New Delhi, India
› Author Affiliations
Further Information

Publication History

Publication Date:
05 May 2018 (online)

INTRODUCTION

Near-infrared spectroscopy (NIRS) is a non-invasive technique for measuring regional oxygen saturation (rsO2). It provides real-time information of changes in rSO2 of cerebral and somatic tissues. It can provide an early warning of decreased oxygen delivery. Tissue ischaemia is a significant contributor to increased morbidity and mortality, and thus measurement of tissue oxygenation is of paramount importance in critical care settings. In 1977, Franz Jöbsis first observed that light in the near-infrared light spectrum (wavelength 700–950 nm) can traverse biological tissue because of the relative transparency of tissue to light in this wavelength range.[1] This discovery later led to the development of NIRS technique to measure tissue oxygen saturation.

NIRS relies on ‘Beer-Lambert law’ (i.e., measurement of a substance concentration based on its absorption of light). Thus, measurement is based on determining haemoglobin oxygenation according to the light absorbed by haemoglobin.[2] The absorption of light is proportional to the concentration of certain chromophore molecules, mainly iron in haemoglobin and copper in cytochrome. In the brain, the primary infra-red light absorbing molecules are metal complex chromophores, namely, oxyhaemoglobin, deoxyhaemoglobin and cytochrome-C oxidase. Because about 70% of the blood in the brain is in the veins and capillaries and 25% in the arteries, most of the haemoglobin is in the venous circulation. Thus, NIRS gives a venous-weighted relative oxygen index of tissue beneath the probe.[3] [4] Cerebral oximetry does not depend on pulsatility of blood flow, unlike pulse oximetry.

The NIRS sensors are applied on either side of the forehead on a clean, dirt-free, non-greasy and non-hairy part of the skin. Each NIRS sensor (optodes) has a light-emitting source and two photodetectors integrated into a self-adhesive rubber plate that is attached to the forehead. The emitter and detectors are situated 4–8 cm apart. Light is generated at specific wavelengths typically by light-emitting diodes, and is usually detected by silicon photodiodes. The light emitted from the emitter passes through the scalp, skull bone and brain tissue. The photodetectors capture the reflected light from the underlying tissue. The light detected by the photodetector close to the emitter passes through the scalp and skull bone, while the light detected by the photodetector farther from the emitter passes through the brain tissue [Figure 1]. Near field photodetection is then substracted from far field photodetection to provide a measurement of brain tissue oxygenation.

Zoom Image
Figure 1: The placement of near-infrared spectroscopy sensors over the forehead and the path of near-infrared light from emitter to 2 detectors

In adults, bilateral frontal cerebral oximetry is used to monitor perfusion to at-risk areas of grey matter within cerebral cortex in the watershed areas between the anterior cerebral artery and middle cerebral artery. The smaller head circumference of neonates and children permits greater depth of penetration and assessment of subcortical tissue oxygenation. The sensors illuminate up to a volume of 10 ml of hemispherical tissue.

There have been several attempts to determine the normal and critical value of regional cerebral oxygen saturation (rScO2). However, data on cut-off values are still limited. The normal values of rScO2 are reported to be 60–80% in various studies. In an animal study, a decrease of the absolute value of rScO2 below 50% was associated with electroencephalogram abnormalities, and a further decrease in rScO2 below 40% lead to increased brain lactate levels.[5] Absolute rScO2 values below 50% have been repeatedly shown to be associated with an unfavourable clinical and/or neurological outcomes. Fischer et al. observed that a decrease in rScO2 below 60% absolute was associated with an increased complication rate in patients undergoing aortic arch surgery.[6] Tang et al. found the incidence of post-operative cognitive dysfunction increased in patients undergoing thoracic surgery even if rScO2 decreased below 65% for more than 5 min.[7] It is more appropriate to interpret the trend changes in rScO2, rather than absolute values.[8] A 20% decline in rScO2 from baseline is considered to be ischaemic threshold.[9] [10] In general, a decrease in rScO2 is reflective of an increase in oxygen extraction as a result of increased metabolism, decreased perfusion and/or stagnant perfusion. High rScO2 may be indicative of increased perfusion, decreased tissue bed metabolism and/or less oxygen extraction.

 
  • REFERENCES

  • 1 Jöbsis FF. Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science 1977; 198: 1264-7
  • 2 Ferrari M, Mottola L, Quaresima V. Principles, techniques, and limitations of near infrared spectroscopy. Can J Appl Physiol 2004; 29: 463-87
  • 3 Gupta N, Dash HH. Neuromonitoring. In: Mehta Y. editor. Textbook of Critical Care. 1st ed.. New Delhi: Jaypee Publishers; 2015. p. 66-89
  • 4 Murkin JM, Arango M. Near-infrared spectroscopy as an index of brain and tissue oxygenation. Br J Anaesth 2009; 103 Suppl (Suppl. 01) i3-13
  • 5 Kurth CD, Levy WJ, McCann J. Near-infrared spectroscopy cerebral oxygen saturation thresholds for hypoxia-ischemia in piglets. J Cereb Blood Flow Metab 2002; 22: 335-41
  • 6 Fischer GW, Lin HM, Krol M, Galati MF, Di Luozzo G, Griepp RB. et al. Noninvasive cerebral oxygenation may predict outcome in patients undergoing aortic arch surgery. J Thorac Cardiovasc Surg 2011; 141: 815-21
  • 7 Tang L, Kazan R, Taddei R, Zaouter C, Cyr S, Hemmerling TM. Reduced cerebral oxygen saturation during thoracic surgery predicts early postoperative cognitive dysfunction. Br J Anaesth 2012; 108: 623-9
  • 8 Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Stoddart HF. Validation in volunteers of a near-infrared spectroscope for monitoring brain oxygenation in vivo . Anesth Analg 1996; 82: 269-77
  • 9 Singer I, Edmonds HL. Tissue oximetry for the diagnosis of neurally mediated syncope. Pacing Clin Electrophysiol 2000; 23 (11 Pt 2) 2006-9
  • 10 Moritz S, Kasprzak P, Arlt M, Taeger K, Metz C. Accuracy of cerebral monitoring in detecting cerebral ischemia during carotid endarterectomy: A comparison of transcranial Doppler sonography, near-infrared spectroscopy, stump pressure, and somatosensory evoked potentials. Anesthesiology 2007; 107: 563-9
  • 11 Zheng F, Sheinberg R, Yee MS, Ono M, Zheng Y, Hogue CW. Cerebral near-infrared spectroscopy monitoring and neurologic outcomes in adult cardiac surgery patients: A systematic review. Anesth Analg 2013; 116: 663-76
  • 12 Murkin JM, Adams SJ, Novick RJ, Quantz M, Bainbridge D, Iglesias I. et al. Monitoring brain oxygen saturation during coronary bypass surgery: A randomized, prospective study. Anesth Analg 2007; 104: 51-8
  • 13 Slater JP, Guarino T, Stack J, Vinod K, Bustami RT, Brown 3rd JM. et al. Cerebral oxygen desaturation predicts cognitive decline and longer hospital stay after cardiac surgery. Ann Thorac Surg 2009; 87: 36-44
  • 14 de Tournay-Jetté E, Dupuis G, Bherer L, Deschamps A, Cartier R, Denault A. The relationship between cerebral oxygen saturation changes and postoperative cognitive dysfunction in elderly patients after coronary artery bypass graft surgery. J Cardiothorac Vasc Anesth 2011; 25: 95-104
  • 15 Samra SK, Dy EA, Welch K, Dorje P, Zelenock GB, Stanley JC. Evaluation of a cerebral oximeter as a monitor of cerebral ischemia during carotid endarterectomy. Anesthesiology 2000; 93: 964-70
  • 16 Mille T, Tachimiri ME, Klersy C, Ticozzelli G, Bellinzona G, Blangetti I. et al. Near infrared spectroscopy monitoring during carotid endarterectomy: Which threshold value is critical?. Eur J Vasc Endovasc Surg 2004; 27: 646-50
  • 17 Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS. et al. Cerebral oxygen desaturation events assessed by near-infrared spectroscopy during shoulder arthroscopy in the beach chair and lateral decubitus positions. Anesth Analg 2010; 111: 496-505
  • 18 Hemmerling TM, Bluteau MC, Kazan R, Bracco D. Significant decrease of cerebral oxygen saturation during single-lung ventilation measured using absolute oximetry. Br J Anaesth 2008; 101: 870-5
  • 19 Nielsen HB. Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery. Front Physiol 2014; 5: 93
  • 20 Dunham CM, Ransom KJ, Flowers LL, Siegal JD, Kohli CM. Cerebral hypoxia in severely brain-injured patients is associated with admission Glasgow Coma Scale score, computed tomographic severity, cerebral perfusion pressure, and survival. J Trauma 2004; 56: 482-9
  • 21 Gopinath SP, Robertson CS, Contant CF, Narayan RK, Grossman RG, Chance B. Early detection of delayed traumatic intracranial hematomas using near-infrared spectroscopy. J Neurosurg 1995; 83: 438-44
  • 22 Steiner LA, Pfister D, Strebel SP, Radolovich D, Smielewski P, Czosnyka M. Near-infrared spectroscopy can monitor dynamic cerebral autoregulation in adults. Neurocrit Care 2009; 10: 122-8
  • 23 Villringer A, Planck J, Hock C, Schleinkofer L, Dirnagl U. Near infrared spectroscopy (NIRS): A new tool to study hemodynamic changes during activation of brain function in human adults. Neurosci Lett 1993; 154: 101-4
  • 24 Hoshi Y. Functional near-infrared spectroscopy: Current status and future prospects. J Biomed Opt 2007; 12: 062106
  • 25 Hillman EM. Optical brain imaging in vivo: Techniques and applications from animal to man. J Biomed Opt. 2007 12: 051402
  • 26 Irani F, Platek SM, Bunce S, Ruocco AC, Chute D. Functional near infrared spectroscopy (fNIRS): Anemerging neuroimaging technology with important applications for the study of brain disorders. Clin Neuropsychol 2010; 21: 9-37
  • 27 Yokose N, Sakatani K, Murata Y, Awano T, Igarashi T, Nakamura S. et al. Bedside monitoring of cerebral blood oxygenation and hemodynamics after aneurysmal subarachnoid hemorrhage by quantitative time-resolved near-infrared spectroscopy. World Neurosurg 2010; 73: 508-13
  • 28 Liebert A, Wabnitz H, Steinbrink J, Möller M, Macdonald R, Rinneberg H. et al. Bed-side assessment of cerebral perfusion in stroke patients based on optical monitoring of a dye bolus by time-resolved diffuse reflectance. Neuroimage 2005; 24: 426-35
  • 29 Terborg C, Bramer S, Harscher S, Simon M, Witte OW. Bedside assessment of cerebral perfusion reductions in patients with acute ischaemic stroke by near-infrared spectroscopy and indocyanine green. J Neurol Neurosurg Psychiatry 2004; 75: 38-42
  • 30 Boas DA, Dale AM, Franceschini MA. Diffuse optical imaging of brain activation: Approaches to optimizing image sensitivity, resolution, and accuracy. Neuroimage 2004; 23 Suppl (Suppl. 01) S275-88
  • 31 Reinhard M, Wehrle-Wieland E, Grabiak D, Roth M, Guschlbauer B, Timmer J. et al. Oscillatory cerebral hemodynamics – The macro- vs. microvascular level. J Neurol Sci 2006; 250: 103-9
  • 32 Pine DJ, Weitz DA, Chaikin PM, Herbolzheimer E. Diffusing wave spectroscopy. Phys Rev Lett 1988; 60: 1134-7
  • 33 Durduran T, Zhou C, Edlow BL, Yu G, Choe R, Kim MN. et al. Transcranial optical monitoring of cerebrovascular hemodynamics in acute stroke patients. Opt Express 2009; 17: 3884-902
  • 34 Cui X, Bray S, Bryant DM, Glover GH, Reiss AL. A quantitative comparison of NIRS and fMRI across multiple cognitive tasks. Neuroimage 2011; 54: 2808-21