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Soehle M, Langer J, Schindler E, Manekeller S, Coburn M, Thudium M. Effect of Extracerebral Contamination on Near-infrared Spectroscopy as Revealed during Organ Donation: A Prospective Observational Study in Brain-dead Organ Donors. Anesthesiology 2024; 140:231-239. [PMID: 37938036 DOI: 10.1097/aln.0000000000004828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
BACKGROUND Near-infrared spectroscopy (NIRS) has been utilized widely in anesthesia and intensive care to monitor regional cerebral oxygen saturation (rScO2). A normal oxygenation of extracerebral tissues may overlay and thereby mask cerebral desaturations, a phenomenon known as extracerebral contamination. The authors investigated the effect of a cessation of extracerebral tissue perfusion on rScO2 in patients with anoxic brains. METHODS In a single-center, prospective, observational study, brain-dead adults undergoing organ donation were investigated. rScO2 was measured bifrontally using the INVOS 5100C/7100 as well as the ForeSight Elite system. To achieve an efficient conservation of organs and to prevent a redistribution of the perfusion fluid to other tissues, the aorta was clamped before organ perfusion. rScO2 was monitored until at least 40 min after aortic clamping. The primary outcome was the amount of extracerebral contamination as quantified by the absolute decrease in rScO2 after aortic clamping. Secondary outcomes were the absolute rScO2 values obtained before and after clamping. RESULTS Twelve organ donors were included. Aortic clamping resulted in a significantly (P < 0.001) greater absolute decrease in rScO2 when comparing the INVOS (43.0 ± 9.5%) to the ForeSight (27.8 ± 7.1%) monitor. Before aortic clamping, near-normal rScO2 values were obtained by the INVOS (63.8 ± 6.2%) and the ForeSight monitor (67.7 ± 6.5%). The rScO2 significantly (P < 0.001) dropped to 20.8 ± 7.8% (INVOS) and 39.9 ± 8.1% (ForeSight) 30 min after clamping, i.e., a condition of a desaturation of both extracerebral and cerebral tissues. CONCLUSIONS The abrupt end of extracerebral contamination, caused by aortic clamping, affected both NIRS monitors to a considerable extent. Both the INVOS and the ForeSight monitor were unable to detect severe cerebral hypoxia or anoxia under conditions of normal extracerebral oxygenation. While both NIRS monitors may guide measures to optimize arterial oxygen supply to the head, they should not be used with the intention to detect isolated cerebral desaturations. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Martin Soehle
- Department of Anesthesiology and Intensive Care Medicine, and Inhouse Transplant Coordination Office of the Medical Director, University Hospital Bonn, Bonn, Germany
| | - Juliane Langer
- Inhouse Transplant Coordination Office of the Medical Director, University Hospital Bonn, Bonn, Germany
| | - Ehrenfried Schindler
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Steffen Manekeller
- Department of General, Visceral, Thoracic and Vascular Surgery, University Hospital Bonn, Bonn, Germany
| | - Mark Coburn
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Marcus Thudium
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
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Abstract
Strategies for basic and advanced neuromonitoring techniques are reviewed. Cerebral hyperthermia during rewarming and unrecognized jugular venous obstruction are associated with cerebral compromise and can be readily detected and avoided. The strengths and limitations of transcranial Doppler and electroencephalographic monitoring are reviewed, as is use of noninvasive cerebral optical spectroscopy and jugular venous oximetry. The potential for reduction in perioperative stroke by using epiaortic scanning to detect and avoid otherwise nonpalpable atherosclerotic plaque, is also reviewed.
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Affiliation(s)
- John M. Murkin
- University Hospital Campus-LHSC, University of Western Ontario, London, Ontario, Canada; Department of Anesthesiology and Perioperative Medicine, University Hospital Campus-LHSC, 339 Windermere Rd., London, Ontario, Canada N6A 5A5
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Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position: A Prospective Interventional Study with a Randomized Comparison of Two Anesthetics. Anesthesiology 2015; 123:765-74. [PMID: 26244887 DOI: 10.1097/aln.0000000000000798] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Beach chair positioning during general anesthesia is associated with cerebral oxygen desaturation. Changes in cerebral oxygenation resulting from the interaction of inspired oxygen fraction (FIO2), end-tidal carbon dioxide (PETCO2), and anesthetic choice have not been fully evaluated in anesthetized patients in the beach chair position. METHODS This is a prospective interventional within-group study of patients undergoing shoulder surgery in the beach chair position that incorporated a randomized comparison between two anesthetics. Fifty-six patients were randomized to receive desflurane or total intravenous anesthesia with propofol. Following induction of anesthesia and positioning, FIO2 and minute ventilation were sequentially adjusted for all patients. Regional cerebral oxygenation (rSO2) was the primary outcome and was recorded at each of five set points. RESULTS While maintaining FIO2 at 0.3 and PETCO2 at 30 mmHg, there was a decrease in rSO2 from 68% (SD, 12) to 61% (SD, 12) (P < 0.001) following beach chair positioning. The combined interventions of increasing FIO2 to 1.0 and increasing PETCO2 to 45 mmHg resulted in a 14% point improvement in rSO2 to 75% (SD, 12) (P <0.001) for patients anesthetized in the beach chair position. There was no significant interaction effect of the anesthetic at the study intervention points. CONCLUSIONS Increasing FIO2 and PETCO2 resulted in a significant increase in rSO2 that overcomes desaturation in patients anesthetized in the beach chair position and that appears independent of anesthetic choice.
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He JW, Liu H, Peng YB. The Scalp Confounds Near-Infrared Signal from Rat Brain Following Innocuous and Noxious Stimulation. Brain Sci 2015; 5:387-99. [PMID: 26426058 PMCID: PMC4701019 DOI: 10.3390/brainsci5040387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 09/02/2015] [Accepted: 09/11/2015] [Indexed: 11/16/2022] Open
Abstract
Functional near-infrared imaging (fNIRI) is a non-invasive, low-cost and highly portable technique for assessing brain activity and functions. Both clinical and experimental evidence suggest that fNIRI is able to assess brain activity at associated regions during pain processing, indicating a strong possibility of using fNIRI-derived brain activity pattern as a biomarker for pain. However, it remains unclear how, especially in small animals, the scalp influences fNIRI signal in pain processing. Previously, we have shown that the use of a multi-channel system improves the spatial resolution of fNIRI in rats (without the scalp) during pain processing. Our current work is to investigate a scalp effect by comparing with new data from rats with the scalp during innocuous or noxious stimulation (n = 6). Results showed remarkable stimulus-dependent differences between the no-scalp and intact-scalp groups. In conclusion, the scalp confounded the fNIRI signal in pain processing likely via an autonomic mechanism; the scalp effect should be a critical factor in image reconstruction and data interpretation.
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Affiliation(s)
- Ji-Wei He
- Departments of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA.
- Department of Neurological Surgery, University of California San Francisco, 1700 Owens Street, San Francisco, CA 94158, USA.
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA.
| | - Yuan Bo Peng
- Departments of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA.
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Bacigaluppi S, Zona G, Secci F, Spena G, Mavilio N, Brusa G, Agid R, Krings T, Ottonello G, Fontanella M. Diagnosis of cerebral vasospasm and risk of delayed cerebral ischemia related to aneurysmal subarachnoid haemorrhage: an overview of available tools. Neurosurg Rev 2015; 38:603-18. [DOI: 10.1007/s10143-015-0617-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 11/16/2014] [Indexed: 01/01/2023]
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Demir G, Çukurova Z, Eren G, Hergünsel O. Comparison of the effects of on-pump and off-pump coronary artery bypass surgery on cerebral oxygen saturation using near-infrared spectroscopy. Korean J Anesthesiol 2014; 67:391-7. [PMID: 25558339 PMCID: PMC4280476 DOI: 10.4097/kjae.2014.67.6.391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 07/07/2014] [Accepted: 07/15/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Central nervous system complications are the most clinically important of those affecting mortality in patients undergoing coronary artery surgery. Newly developed sophisticated techniques and surgical interventions obviating the need for cardiopulmonary pumps have facilitated avoidance of these complications. In this study, we compared the impact of on-pump and off-pump coronary artery bypass surgery on cerebral oxygenation using near-infrared spectroscopy. METHODS This study included 40 patients with no comorbidities who were scheduled for on-pump (n = 20) and off-pump (n = 20) cardiac surgery. Preoperative and postoperative Standardized Mini-Mental State Examination (SMMSE) scores, perioperative mean arterial blood pressure (MAP), hematocrit (Hct), peripheral oxygen saturation (SpO2), regional cerebral oximetry values (rSO2), body temperature, and partial pressure of carbon dioxide (PCO2) were recorded, for all patients. Intergroup and intragroup comparisons were then performed. RESULTS The mean operative time was longer in the on-pump group. SMMSE scores were similar and relevant postoperative values were lower in both groups. Perioperative MAP, PCO2, and SpO2 were similar in both groups. SpO2 and PCO2 did not differ from baseline levels in either group, while the postextubation MAP at 2 h postoperatively remained low. Hct levels decreased during the perioperative and postoperative periods, while the body temperature declined perioperatively and to a greater degree in the on-pump group. The intraoperative and postoperative rSO2 decreased in both groups. In the on-pump group, the decrease in rSO2 was more prominent during the interval between the start and closure of the sternotomy. CONCLUSIONS Physiological alterations that occur during coronary artery surgery affect cerebral oxygenation during and after the operation irrespective of the application of a cardiopulmonary pump. Cerebral oxygenation decreases to a greater extent during on-pump surgery; however, probably because of the neuroprotective effects of hypothermia, the postoperative changes resemble those of off-pump surgery.
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Affiliation(s)
- Guray Demir
- Department of Anesthesiology and Reanimation, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
| | - Zafer Çukurova
- Department of Anesthesiology and Reanimation, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
| | - Gülay Eren
- Department of Anesthesiology and Reanimation, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
| | - Oya Hergünsel
- Department of Anesthesiology and Reanimation, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
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Hirasawa A, Yanagisawa S, Tanaka N, Funane T, Kiguchi M, Sørensen H, Secher NH, Ogoh S. Influence of skin blood flow and source-detector distance on near-infrared spectroscopy-determined cerebral oxygenation in humans. Clin Physiol Funct Imaging 2014; 35:237-44. [DOI: 10.1111/cpf.12156] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
Affiliation(s)
- Ai Hirasawa
- Graduate school of Engineering; Toyo University; Kawagoe-shi Saitama Japan
| | - Shintaro Yanagisawa
- Department of Biomedical Engineering; Faculty of Science and Engineering; Toyo University; Kawagoe-shi Saitama Japan
| | - Naoki Tanaka
- Graduate school of Engineering; Toyo University; Kawagoe-shi Saitama Japan
- Department of Biomedical Engineering; Faculty of Science and Engineering; Toyo University; Kawagoe-shi Saitama Japan
| | - Tsukasa Funane
- Hitachi, Ltd.; Central Research Laboratory; Hatoyama-machi Saitama Japan
| | - Masashi Kiguchi
- Hitachi, Ltd.; Central Research Laboratory; Hatoyama-machi Saitama Japan
| | - Henrik Sørensen
- Department of Anesthesia; Rigshospitalet; The Copenhagen Muscle Research Center; University of Copenhagen; Copenhagen Denmark
| | - Niels H. Secher
- Department of Anesthesia; Rigshospitalet; The Copenhagen Muscle Research Center; University of Copenhagen; Copenhagen Denmark
| | - Shigehiko Ogoh
- Graduate school of Engineering; Toyo University; Kawagoe-shi Saitama Japan
- Department of Biomedical Engineering; Faculty of Science and Engineering; Toyo University; Kawagoe-shi Saitama Japan
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The influence of basic ventilation strategies on cerebral oxygenation in anesthetized patients without vascular disease. J Clin Monit Comput 2010; 24:421-5. [PMID: 21061050 DOI: 10.1007/s10877-010-9265-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Optimizing cerebral oxygenation is of paramount importance in certain intraoperative situations. There is, however, a paucity of published data pertaining to changes in cerebral oxygenation seen with increases in the inspired fraction of oxygen (FIO2) or end-tidal carbon dioxide (PETCO2) in anesthetized patients without vascular disease. Here we tested the hypothesis that changes in FIO2 or PETCO2 correlate to a significant change in regional cerebral oxygenation (rSO2) in anesthetized patients without vascular disease. METHODS This was a prospective pilot study approved by the IRB. We measured rSO2 using the INVOS 5100B monitor in ten anesthetized patients. Patients were excluded if they had a history of or risk factors for vascular disease, suffered from respiratory failure, or did not speak English. Following induction of anesthesia and intubation, FIO2 and minute ventilation were sequentially adjusted. At each set point, rSO2 was recorded and arterial blood gas analysis was performed. Each patient acted as their own control. A paired-sample t test was used to evaluate the change in rSO2 resultant upon each intervention. RESULTS The baseline rSO2 was measured with patients awake, breathing room air and varied between 48 and 72%. While maintaining PETCO2 in the range 30-35 mmHg, rSO2 was 8% higher when 100% oxygen was delivered compared to FIO2 30% (P = 0.021). While maintaining PETCO2 in the range 40-45 mmHg, rSO2 was 7% higher when 100% oxygen is delivered compared to FIO2 30% (P = 0.032). While maintaining FIO2 at 100%, rSO2 was 2% higher when PETCO2 was in the range 40-45 mmHg compared to PETCO2 30-35 mmHg (P = 0.017). While maintaining FIO2 at 30%, rSO2 was not statistically different between PECO2 40-45 mmHg and PETCO2 30-35 mmHg. CONCLUSIONS Modulating oxygenation and ventilation in anesthetized patients without vascular disease leads to measurable changes in rSO2.
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Picton P, Chambers J, Shanks A, Dorje P. The Influence of Inspired Oxygen Fraction and End-Tidal Carbon Dioxide on Post–Cross-Clamp Cerebral Oxygenation During Carotid Endarterectomy Under General Anesthesia. Anesth Analg 2010; 110:581-7. [DOI: 10.1213/ane.0b013e3181c5f160] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Multimodality monitoring of cerebral physiology encompasses the application of different monitoring techniques and integration of several measured physiologic and biochemical variables into assessment of brain metabolism, structure, perfusion, and oxygenation status. Novel monitoring techniques include transcranial Doppler ultrasonography, neuroimaging, intracranial pressure, cerebral perfusion, and cerebral blood flow monitors, brain tissue oxygen tension monitoring, microdialysis, evoked potentials, and continuous electroencephalogram. Multimodality monitoring enables immediate detection and prevention of acute neurologic injury as well as appropriate intervention based on patients' individual disease states in the neurocritical care unit. Real-time analysis of cerebral physiologic, metabolic, and cardiovascular parameters simultaneously has broadened knowledge about complex brain pathophysiology and cerebral hemodynamics. Integration of this information allows for more precise diagnosis and optimization of management of patients with brain injury.
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Affiliation(s)
- Katja Elfriede Wartenberg
- Neurological Intensive Care Unit, New York Presbyterian Hospital, Columbia University Medical Center, 710 W. 168th Street, New York, NY 10032, USA
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11
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Abstract
Neurological complications during critical illness remain a frequent cause of morbidity and mortality. To date, monitors of cerebral function including electroencephalography, jugular bulb mixed venous oxygen saturation and transcranial Doppler, either require an invasive procedure and/or are not sensitive enough to effectively identify patients at risk for cerebral hypoxia. Near-infrared spectroscopy is a noninvasive device that uses infrared light, a technique similar to pulse oximetry, to penetrate living tissue and estimate brain tissue oxygenation by measuring the absorption of infrared light by tissue chromophores. The following article reviews the latest technology available to monitor cerebral oxygenation, near-infrared spectroscopy, its advantages and disadvantages, the currently available evidence-based medicine that demonstrates that this technology can identify deficits in cerebral oxygenation, and that monitoring such deficits allows for therapy to reverse cerebral oxygenation issues and thereby prevent long-term neurological sequelae.
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Affiliation(s)
- Joseph D Tobias
- Department of Anesthesiology, University of Missouri, Columbia, MO 65212, USA.
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12
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Abstract
Multimodality monitoring of cerebral physiology encompasses the application of different monitoring techniques and integration of several measured physiological and biochemical variables into the assessment of brain metabolism, structure, perfusion and oxygenation status, in addition to clinical evaluation. Novel monitoring techniques include transcranial Doppler ultrasonography, neuroimaging, intracranial pressure, cerebral perfusion and cerebral blood flow monitors, brain tissue oxygen tension monitoring, microdialysis, evoked potentials and continuous electroencephalography. Multimodality monitoring enables the immediate detection and prevention of acute neurological events, as well as appropriate intervention based on a patient’s individual disease state in the neurocritical care unit. Simultaneous real-time analysis of cerebral physiological, metabolic and cardiovascular parameters has broadened knowledge regarding complex brain pathophysiology and cerebral hemodynamics. Integration of this information allows for a more precise diagnosis and optimization of management of patients with brain injury.
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Affiliation(s)
- Katja Elfriede Wartenberg
- Columbia University, Division of Stroke and Critical Care, Neurological Institute, 710 West 168th Street, NY 10032, USA
| | - J Michael Schmidt
- Columbia University, Division of Stroke and Critical Care, Neurological Institute, 710 W, 168th Street, NY 10032, USA
| | - Derk W Krieger
- Cleveland Clinic Foundation, Section of Stroke and Neurologic Intensive Care, Department of Neurology, S91, 9500 Euclid Avenue, OH 44195, USA
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Gatto R, Hoffman W, Mueller M, Flores A, Valyi-Nagy T, Charbel FT. Frequency domain near-infrared spectroscopy technique in the assessment of brain oxygenation: a validation study in live subjects and cadavers. J Neurosci Methods 2006; 157:274-7. [PMID: 16730069 DOI: 10.1016/j.jneumeth.2006.04.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2006] [Revised: 04/21/2006] [Accepted: 04/21/2006] [Indexed: 11/16/2022]
Abstract
BACKGROUND Studies with continuous wave near infrared spectroscopy (CW-NIRS) have shown little difference in brain oxygenation of dead compared to live subjects. We determined brain oxyhemoglobin (OHb) and deoxyhemoglobin (HHb) concentrations in healthy volunteers and cadavers using frequency domain near infrared spectroscopy (FD-NIRS). METHODS Regional OHb and HHb, brain oxygen saturation (SO2), and total hemoglobin (tHb) were determined. Nine patients who died in the hospital were evaluated by FD-NIRS in the morgue 7-96 h after death was confirmed. Ten volunteers served as a control group. RESULTS Absolute concentrations of brain tissue OHb and HHb were 24.9 +/- 9.1 uM and 13.8 +/- 32 uM, respectively, in live subjects. In dead subjects, OHb was 1.3 +/- 2.1 uM and HHb was 30.8 +/- 14.4 uM (both P < 0.05 compared to live). OHb showed a 90% decrease within 7h of death. There was a significant trend for a continued decrease in OHb from 7 to 96 h. CONCLUSION OHb decreased and HHb increased in dead patients compared to live volunteers. Depletion of OHb primarily occurred within 7 h of death but continued gradually over 96 h. FD-NIRS was a novel technique for determining OHb and HHb changes following death.
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Affiliation(s)
- Rodolfo Gatto
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Sato C, Shimada M, Yamada Y, Hoshi Y. Extraction of depth-dependent signals from time-resolved reflectance in layered turbid media. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:064008. [PMID: 16409073 DOI: 10.1117/1.2136312] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We try a new approach with near-IR time-resolved spectroscopy, to separate optical signals originated in the upper layer from those in the lower layer and to selectively determine the absorption coefficient (mu(a)) of each layer in a two-layered turbid medium. The difference curve in the temporal profiles of light attenuation between a target and a reference medium is divided into segments along the time axis, and a slope of each segment is calculated to determine the depth-dependent mu(a). The depth-dependent mu(a) values are estimated under various conditions in which mu(a) and the reduced scattering coefficient (mu(s)') of each layer are changed with a Monte Carlo simulation and in phantom experiments. Temporal variation of them represents the difference in mu(a) between two layers when mu(s)' of a reference is the same as that of the upper layer of the target. The discrepancies between calculated mu(a) and the real mu(a) depend on the ratio of the real mu(a) of the upper layer to that of the lower layer, and our approach enables us to estimate the ratio of mu(a) between the two layers. These results suggest the potential that mu(a) of the lower layer can be determined by our procedure.
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Affiliation(s)
- Chie Sato
- Tokyo Institute of Psychiatry, Department of Integrated Neuroscience, 2-1-8 Kamikitazawa, Setagaya-ku, Tokyo 156-8585, Japan.
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Lozano S, Mossad E. Cerebral function monitors during pediatric cardiac surgery: can they make a difference? J Cardiothorac Vasc Anesth 2005; 18:645-56. [PMID: 15578481 DOI: 10.1053/j.jvca.2004.07.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sara Lozano
- Department of Cardiothoracic Anesthesia, Division of Anesthesiology & Critical Care Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
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Cua CL, Hoffman TM, Taeed R, Weinstein S, Gomez D, Olshove VF, Craenen JM. Cerebral saturations trend with mixed venous saturations in patients undergoing extracorporeal life support. Perfusion 2005; 19:171-6. [PMID: 15298425 DOI: 10.1191/0267659104pf738oa] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cerebral saturation (SCO2) monitors are noninvasive tools that continuously measure saturations in the cerebral cortex, a predominately venous bed. The purpose of this study was to see if a trend existed between measurements of SCO2 and mixed venous saturation values (SVO2) for patients on extracorporeal life support (ECLS). Six patients required ECLS for cardiac failure after congenital cardiac surgery, and one patient required ECLS for pulmonary failure. Patients were divided into two groups, those without systemic/pulmonary venous mixing (n = 3, Group I) and those with mixing due to an intraatrial shunt or left ventricular vent (n = 4, Group II). The age of patients was 0.4 +/- 0.5 years (mean +/- SD), weight was 5.2 +/- 2.3 kg, and time on ECLS was 8.3 +/- 4.8 days. No significant abnormalities were seen on head imaging. A total of 786 paired data points were collected. Mean values were different; however, there was a significant trend between SCO2 and SVO2 for the entire sample (R2 = 0.66, p < 0.001). Cerebral saturation trends follow mixed venous trends and, therefore, may be helpful in combination with other physical and laboratory findings in the care of the critically ill child.
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Affiliation(s)
- Clifford L Cua
- Division of Cardiology, Department of Pediatrics, Columbus Children's Hospital, The Ohio State University College of Medicine, Columbus, OH 43205-2696, USA
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Abstract
BACKGROUND Neurocritical care is a specialty that focuses on the critical care management of patients with catastrophic neurologic diseases. Brain ischemia and hypoxia are often central causes of brain damage in these patients. Until recently, the only methods widely accepted for monitoring in the neurological intensive care unit have been intracranial pressure and cerebral perfusion pressure monitoring. Recent developments in technology have resulted in several new monitoring techniques that can provide the neurointensivist with information, at the cellular level, that can help guide management. REVIEW SUMMARY The brain requires a continuous blood-borne supply of oxygen and glucose for normal metabolism. Ischemia occurs when supply is insufficient to meet the metabolic demand. Cerebral blood flow can now be directly monitored using laser Doppler or thermal diffusion techniques. Transcranial cerebral oximetry can estimate regional cerebral oxygen saturation, although the reliability is questionable. Jugular bulb oximetry can provide a global assessment of oxygen delivery, and consumption and brain tissue oxygen tension monitoring can provide a focal measurement of cerebral oxygenation. Intracerebral microdialysis can provide information about glucose metabolism and the overall health of the neuron. CONCLUSIONS New monitoring techniques can provide the neurointensivist with crucial information about brain physiology and metabolism. Combining these techniques ("multimodal monitoring") can produce a more accurate overall picture. This approach, along with new computer systems for integrating data at the bedside, may change the way patients with brain injury are monitored and treated in the future.
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Affiliation(s)
- Michael A De Georgia
- Neurological Intensive Care Program, Department of Neurology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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Kishi K, Kawaguchi M, Yoshitani K, Nagahata T, Furuya H. Influence of Patient Variables and Sensor Location on Regional Cerebral Oxygen Saturation Measured by INVOS 4100 Near-Infrared Spectrophotometers. J Neurosurg Anesthesiol 2003; 15:302-6. [PMID: 14508170 DOI: 10.1097/00008506-200310000-00002] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cerebral oximeter based on near-infrared spectroscopy has been used as a continuous, noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Although the absolute rSO2 values have a wide range of variability, the factors affecting a variability of rSO2 values have not been extensively investigated. The authors investigated the influence of patient variables and sensor location on rSO2 measured by the cerebral oximeter INVOS 4100 in 111 patients anesthetized with sevoflurane, fentanyl, and nitrous oxide in oxygen. The sensors for rSO2 measurements were applied on the right forehead (R), 1 cm lateral to R (R1), on the left forehead (L), 1 cm lateral to L (L1), and on the center of the forehead (C). The relationship between the rSO2 values and patient variables were also analyzed. Values of rSO2 at R1 and L1 were significantly lower than those at R and L, respectively. Values of rSO2 at C were significantly higher compared with those at other sites. There were no significant correlations between the rSO2 values and values of weight, height, and head size. Values of rSO2 were similar between males and females. A significant negative correlation between the rSO2 values and age and a positive correlation between the rSO2 values and hemoglobin concentration were observed. These data indicate that patient age, hemoglobin concentration at the measurement, and sensor location can affect rSO2 values.
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Affiliation(s)
- Katsuyoshi Kishi
- Departments of Anesthesiology, Bell Land General Hospital, Osaka, Japan
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Thavasothy M, Broadhead M, Elwell C, Peters M, Smith M. A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near-Infrared Spectrophotometers. Anaesthesia 2002; 57:999-1006. [PMID: 12358958 DOI: 10.1046/j.1365-2044.2002.02826.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study cerebral oxygenation was measured using the NIRO 300 and the INVOS 5100 spectrophotometers in 10 healthy adult volunteers, exposed to varying degrees of hyperoxia and hypoxia. The results showed similar baseline values for tissue oxygenation index and regional cerebral oxygen saturation with mean (SD) values being 64.9% (5.1) and 62.3% (6.0), respectively. The overall bias was -2.1%, with the INVOS 5100 under-reading cerebral oxygenation compared to the NIRO 300, with limits of agreement of +/-14.7%. Both monitors demonstrated similar changes in response to hyperoxia and hypocapnia (coefficient of variance for FIo2 0.45 = 10.0%, FIo2 1.0 = 10.1%, hypocapnia = 14.5%). The reasons for the bias and variability may relate to differences in the methodological approaches of the two monitors. The correlation between the monitors in response to changes in cerebral oxygenation implies that they may be useful as trend monitors in clinical practice.
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Affiliation(s)
- M Thavasothy
- Department of Neuroanaesthesia and Intensive Care, The National Hospital for Neurology and Neurosurgery, Centre for Anaesthesia, UCL Hospitals, London WC1N 3BG, UK
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Abstract
None of the monitors of cerebral oxygenation discussed above has proven to be effective enough to have become a standard of care in any given area of medical treatment. As described above, each has specific and well-defined shortcomings that prevent its widespread use. These shortcomings may not be so much a failure of technology as an acknowledgement of the complexity of our goal: a monitor that can divide the entire brain into small, focal, and discrete areas and accurately measure the oxygen tension in each one. Because we are asking for the functional equivalent of 30 or 40 simultaneous PbtO2 probes, it is small wonder that we are not yet satisfied. Of the three monitors discussed here, the greatest potential may lie with the transcranial cerebral oximetry. The cerebral oximeter has the biggest potential for improvement because it holds the most potential for technical advancement. Although, for instance, jugular venous bulb oximetric catheters may become somewhat more accurate, the biggest drawbacks in that monitor's usefulness lie in human anatomy and intracerebral blood mixing, not catheter accuracy. PbtO2 probes, also, have little room for improvement. Although every technology can be refined, the PbtO2 probes are already accurate. The fact that they are an invasive monitor, and a regional one at that, will relegate them to a limited number of cases. Cerebral oximeters hold more potential. Their greatest limitations lie in technical aspects that can be, and hopefully will be, improved upon in terms of computer technology as well as algorithm accuracy. The fact that cerebral oximeters can be used on any patient, at any time, on almost any case, makes it, potentially, truly an ideal monitor for anesthesiologists and intensivists alike. There is no certainty that any of these limitations will be surmounted, at least to the degree necessary to achieve desired accuracy. But there is much to anticipate.
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Affiliation(s)
- Paul R Smythe
- Department of Anesthesiology, University of Michigan Medical Center, 1500 E. Medical Center Drive, 1H247-UH, Box 0048, Ann Arbor, MI 48109, USA.
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Yoshitani K, Kawaguchi M, Tatsumi K, Kitaguchi K, Furuya H. A comparison of the INVOS 4100 and the NIRO 300 near-infrared spectrophotometers. Anesth Analg 2002; 94:586-90; table of contents. [PMID: 11867380 DOI: 10.1097/00000539-200203000-00020] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
UNLABELLED We determined whether two different devices for measuring near-infrared spectroscopy (NIRS)---the INVOS 4100 and the NIRO 300---produce similar cerebral oxygenation data during the CO(2) challenge test. Nineteen patients anesthetized with sevoflurane, 67% nitrous oxide in oxygen, and fentanyl were studied. A series of measurements of regional cerebral oxygen saturation (rSO(2)), measured by the INVOS 4100, and tissue oxygen index (TOI), measured by the NIRO 300, were performed in the following conditions: 1) normocapnia (PaCO(2), 35--45 mm Hg); 2) hypocapnia (PaCO(2), 25--35 mm Hg); 3) normocapnia; and 4) hypercapnia (PaCO(2), 45--55 mm Hg). Hemodynamic variables, including arterial blood gases and cerebral blood flow velocity, were measured at the same time with transcranial Doppler. The values and percentage changes of rSO(2) and TOI were compared by using regression analysis and Bland and Altman analysis. The rSO(2) showed a significant positive correlation with TOI (r = 0.58, P < 0.01). The percentage change of rSO(2) also showed a significant positive correlation with the percentage change of TOI during the CO(2) challenge (r = 0.85, P < 0.01). Bland and Altman analysis revealed a bias of -0.5% with 2 SD of 15.6% when comparing the rSO(2) value with the TOI value, and it showed a bias of -3.4% with 2 SD of 15.2% when comparing the percentage change of rSO(2) with the percentage change of TOI, indicating unacceptable disagreement of these data. These results indicate that cerebral oxygen saturation and its relative change during the CO(2) challenge may vary depending on the type of NIRS used. Because the measurement technique and algorithm were different in each device, we should carefully consider the clinical application of the values produced by NIRS. IMPLICATIONS Near-infrared spectroscopy (NIRS) has been proposed as a noninvasive clinical method for assessing cerebral oxygenation. The acceptable reliability and validity of NIRS values have not been established despite their widespread use. The INVOS 4100 and the NIRO 300 can display cerebral oxygen saturation as regional cerebral oxygen saturation and tissue oxygenation index, but they produce differing results.
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Affiliation(s)
- Kenji Yoshitani
- Department of Anesthesiology, Nara Medical University, Nara, Japan.
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Abstract
Today's intensivists are provided with more information than ever before, yet current monitors present data from multiple sources in a relatively raw form with virtually no intelligent data integration and processing. In the next century, technological advances in miniaturization, biosensors and computer processing, coupled with an improved understanding of critical illnesses at the molecular level, will lead to the development of a new generation of monitors. Monitoring will move from the traditional macroscopic invasive approach to a noninvasive, molecular analysis of evolving critical disease processes. It is likely that disturbances in homeostasis will become known immediately or before they would otherwise be manifest clinically. Nanotechnology will permit monitoring of critical changes in the intracellular environment or the by-products of cellular metabolism and signal messaging. This article discusses monitoring technologies that hold promise for further development in the next century and point out techniques likely to be abandoned.
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Affiliation(s)
- R Kohli-Seth
- Department of Surgery, Mount Sinai Medical Center, City University of New York, New York, USA
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23
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Shah N, Trivedi NK, Clack SL, Shah M, Shah PP, Barker S. Impact of hypoxemia on the performance of cerebral oximeter in volunteer subjects. J Neurosurg Anesthesiol 2000; 12:201-9. [PMID: 10905567 DOI: 10.1097/00008506-200007000-00001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Adverse neurological events during hypoxic episodes in high-risk patients or in patients not thought to be at risk while undergoing procedures increase morbidity and mortality. The ability to reliably monitor cerebral oxygenation could serve as an indicator for the need of therapeutic intervention and it's overall effect. This study was designed to verify the reliability of the only commercially available continuous noninvasive monitor, the INVOS 3100 (Somanetics Corp., Troy, MI), in subjects with varying levels of hypoxemia. Six adult volunteer subjects were enrolled. After placement of electrocardiogram (EKG), noninvasive blood pressure (NIBP), pulse oximeter (SpO2), cerebral oximeter (rSO2), a 20 g radial artery catheter, and a 4 F oximetric jugular bulb catheter, the subjects were given hypoxic mixtures to breathe to varying levels of desaturation. Arterial and mixed venous blood was drawn for blood-gas analysis at each level of O2 saturation. The cerebral hemoglobin saturation value from the cerebral oximeter was compared to the combined brain saturation using the formula: estimated field saturation between the light source and the detector (fSO2) = 0.25 x the arterial oxygen saturation (SaO2) + 0.75 x the jugular bulb venous oxygen saturation (SjvO2), (fSO2 = 0.25 SaO2 + 0.75 SjvO2). Statistical analysis demonstrated a correlation of 0.67 between rSO2 and fSO2 and a bias of -3.1% with a precision of 12.1%. Minimal bias of 0.38% and precision of 6.22% were calculated for transitional error. We concluded from the study that rSO2 may serve as a reliable indicator of changes in brain oxygenation induced by hypoxemia.
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Affiliation(s)
- N Shah
- Department of Anesthesiology, University of California at Irvine, Orange, USA
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Fearn SJ, Picton AJ, Mortimer AJ, Parry AD, McCollum CN. The contribution of the external carotid artery to cerebral perfusion in carotid disease. J Vasc Surg 2000; 31:989-93. [PMID: 10805890 DOI: 10.1067/mva.2000.104598] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE In the presence of carotid occlusion, the external carotid artery (ECA) becomes an important source of cerebral blood flow, especially if the circle of Willis is incomplete. The contribution of the ECA to hemispheric blood flow in patients with severe ipsilateral carotid stenosis has never been previously investigated. METHODS One hundred eight patients were monitored during sequential cross-clamping of the external (ECA) and then ipsilateral internal carotid artery (ICA) during carotid endarterectomy using transcranial Doppler sonography (TCD) (Neuroguard CDS, Los Angeles, Calif), to measure middle cerebral artery blood flow velocity, and near-infrared spectroscopy, to measure regional cerebral oxygen saturation (CsO(2)) (Invos 3100A; Somanetics, Troy, Mich). RESULTS On the ipsilateral ECA cross-clamp, the median fall in CsO(2) was 3% (interquartile range, 1%-4%; P <.0001). On addition of the ICA cross-clamp there was a further fall of 3% and a total fall of 6% (3%-9%; P <.0001). The median percentage fall in middle cerebral artery blood flow velocity on ECA clamping was 12% (4%-24%; P <.0001); on ICA clamping it was 48% (25%-74%; P <.0001). Falls in TCD on ECA clamping were greater with increasing severity of ipsilateral ICA stenosis. The correlation between CsO(2) and TCD on external clamping, although less strong than that on internal clamping, was statistically significant r = 0.32; P =.01; Spearman rank correlation). CONCLUSIONS The falls in TCD and CsO(2) were of a similar order of magnitude and must therefore reflect a fall in cerebral perfusion. The ipsilateral ECA contributes significantly to intracranial blood flow and oxygen saturation in severe carotid stenosis.
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Affiliation(s)
- S J Fearn
- Department of Surgery, University Hospital of South Manchester, UK
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25
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Van de Ven MJ, Colier WN, Kersten BT, Oeseburg B, Folgering H. Cerebral blood volume responses to acute PaCO2 changes in humans, assessed with near infrared spectroscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 471:199-207. [PMID: 10659148 DOI: 10.1007/978-1-4615-4717-4_24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- M J Van de Ven
- Department of Pulmonology Dekkerswald, University of Nijmegen, Groesbeek, The Netherlands
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26
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van de Ven MJ, Colier WN, Walraven D, Oeseburg B, Folgering H. Cerebral blood flow in humans measured with near infrared spectroscopy is not reproducible. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 471:749-58. [PMID: 10659210 DOI: 10.1007/978-1-4615-4717-4_86] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- M J van de Ven
- Department of Pulmonology Dekkerswald, University of Nijmegen, The Netherlands
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Fuchs G, Schwarz G, Kulier A, Litscher G. The influence of positioning on spectroscopic measurements of brain oxygenation. J Neurosurg Anesthesiol 2000; 12:75-80. [PMID: 10774599 DOI: 10.1097/00008506-200004000-00001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study was designed to evaluate the influence of body position during neurosurgical and cerebrovascular operations on regional cerebral oxygen saturation (rSO2). Awake volunteers (group I; n = 14), anesthetized patients (group II; n = 48) undergoing lumbar discectomy, and 12 patients undergoing carotid endarterectomy (group III) with internal carotid artery (ICA) stenosis were studied. Anesthesia in the patient groups was performed with sevoflurane (1.1 Vol% insp.) in N2O2/O2 mixture (FiO2 0.4) rSO2 was monitored with a INVOS 4100 cerebral oxymeter (Somanetics Corporation, Troy, MI). Measurements were done in all groups in supine position with head turned to the right and left side. Furthermore, in groups I and II, rSO2 was measured in right lateral, left lateral, prone, or sitting position. In each position the parameters were registered at three times (1, 3, and 5 min after taking up the position). In the healthy volunteers, the mean rSO2 values of both hemispheres were 71.3 +/- 5.0%. No significant changes of rSO2 were found interhemispherical and upon turning the head to both sides or positioning to the prone and both lateral positions. After assuming the sitting position, the decrease of rSO2 was not significant. In group II, rSO2 decreased significantly in the sitting position. In group III, baseline readings for rSO2 obtained from the side of ICA stenosis were significantly lower, compared to the contralateral side. After turning the head to the ipsilateral side, this difference diminished. In contrast, turning the head toward the contralateral side, the rSO2 difference remained nearly constant, both values decreasing constantly throughout the observation period. In conclusion, after different positioning maneuvers awake and under anesthesia, alterations of rSO2 can be registrated by near-infrared spectroscopy (NIRS).
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Affiliation(s)
- G Fuchs
- Department of Anesthesiology and Intensive Care Medicine, University of Graz, Austria
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28
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Al-Rawi PG, Smielewski P, Hobbiger H, Ghosh S, Kirkpatrick PJ. Assessment of spatially resolved spectroscopy during cardiopulmonary bypass. JOURNAL OF BIOMEDICAL OPTICS 1999; 4:208-216. [PMID: 23015206 DOI: 10.1117/1.429911] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Controversy remains about which tissue is primarily responsible for light attenuation of near infrared spectroscopy (NIRS) in the adult, the spatial resolution provided and the preferred algorithm for quantification. Until recently, changes in NIRS have not been fully quantified and have been difficult to interpret without sophisticated computation. A new development by Hamamatsu Photonics, the spatially resolved spectrometer (SRS), may be able to give a quantitative measure of oxygen saturation. We have incorporated the SRS into a multimodality monitoring system for the purpose of direct validation against jugular bulb oxygen saturation (SjO2) in patients undergoing routine cardiopulmonary bypass (CPB). The importance of this investigation is in the development of the SRS machine which shows potential as a useful clinical tool. The results demonstrated good correlation between SRS and SjO2 in 12 out of the 24 patients studied. Although these results are encouraging, this study suggests that the SRS, in its present form, is not a reliable clinical monitor of cerebral oxygen saturation during CPB. © 1999 Society of Photo-Optical Instrumentation Engineers.
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29
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Liu G, Burcev I, Pott F, Ide K, Horn A, Secher NH. Middle cerebral artery flow velocity and cerebral oxygenation during abdominal aortic surgery. Anaesth Intensive Care 1999; 27:148-53. [PMID: 10212710 DOI: 10.1177/0310057x9902700203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cerebral perfusion was evaluated in twelve patients undergoing elective infra-renal abdominal aortic aneurysmectomy by transcranial Doppler ultrasonography-determined middle cerebral artery mean flow velocity, near-infrared spectroscopy-assessed cerebral oxygen saturation and systemic haemodynamic variables. The middle cerebral artery mean flow velocity and cerebral oxygen saturation decreased during cross-clamping of the aorta, and both increased upon declamping of the aorta with the oxygen saturation change lagging behind the change in the flow velocity. The changes in cerebral flow velocity and oxygen saturation paralleled the deviations in cardiac output and end-tidal carbon dioxide tension.
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Affiliation(s)
- G Liu
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Denmark
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30
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Beese U, Langer H, Lang W, Dinkel M. Comparison of near-infrared spectroscopy and somatosensory evoked potentials for the detection of cerebral ischemia during carotid endarterectomy. Stroke 1998; 29:2032-7. [PMID: 9756577 DOI: 10.1161/01.str.29.10.2032] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE We sought to assess the clinical value of regional cerebral saturation (rSO2) obtained by means of the cerebral oximeter INVOS 3100A (Somanetics) in comparison to monitoring of somatosensory evoked potentials (SEP) for the reliable detection of severe cerebral ischemia requiring shunt placement in the individual patient undergoing carotid surgery under general anesthesia. METHODS In 317 patients undergoing reconstructive surgery on the internal carotid artery, simultaneous recordings of SEP and rSO2 were obtained throughout the operation. RESULTS All 287 patients with preserved cortical SEP remained neurologically intact. Shunt placement was performed in 27 patients (9%) after flattening of cortical SEP during cross-clamping of the internal carotid artery. A stable rSO2 value just before cross-clamping and the lowest value after cross-clamping were registered, and the decrease was calculated. A statistically significant (P<0.01) decrease of rSO2 after cross-clamping could be found in patients without (64.9+/-8.3% to 60.9+/-9.9%) as well as in patients with consecutive loss of cortical SEP (65.8+/-9.1% to 56.1+/-13.4%). The difference of the decrease of rSO2 in both groups was highly significant (6.9+/-9.0% versus 15.6+/-14.0%; P<0.001). However, substantial interindividual variability of rSO2 and derived change of rSO2 did not allow the definition of a threshold value indicating need of shunt placement. CONCLUSIONS The reliability of SEP for the detection of clamp-related hypoperfusion has been reaffirmed. As long as rSO2 threshold values indicating critical cerebral ischemia are not defined, therapeutic interventions based on monitoring with the cerebral oximeter INVOS 3100A are not justified.
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Affiliation(s)
- U Beese
- Departments of Anesthesiology, Division of Vascular Surgery, University of Erlangen-Nuremberg, Erlangen, FRG
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Kirkpatrick PJ, Lam J, Al-Rawi P, Smielewski P, Czosnyka M. Defining thresholds for critical ischemia by using near-infrared spectroscopy in the adult brain. J Neurosurg 1998; 89:389-94. [PMID: 9724112 DOI: 10.3171/jns.1998.89.3.0389] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Signal changes in adult extracranial tissues may have a profound effect on cerebral near-infrared spectroscopy (NIRS) measurements. During carotid surgery NIRS signals provide the opportunity to determine the relative contributions from the intra- and extracranial vascular territories, allowing for a more accurate quantification. In this study the authors applied multimodal monitoring methods to patients undergoing carotid endarterectomy and explored the hypothesis that NIRS can define thresholds for cerebral ischemia, provided extracranial NIRS signal changes are identified and removed. Relative criteria for intraoperative severe cerebral ischemia (SCI) were applied to 103 patients undergoing carotid endarterectomy. METHODS One hundred three patients underwent carotid endarterectomy. An intraoperative fall in transcranial Doppler-detected middle cerebral artery flow velocity (%deltaFV) of greater than 60% accompanied by a sustained fall in cortical electrical activity were adopted as criteria for SCI. Ipsilateral frontal NIRS recorded the total difference in concentrations of oxyhemoglobin and deoxyhemoglobin (Total deltaHb(diff)). Interrupted time series analysis following clamping of the external carotid artery (ECA) and the internal carotid artery (ICA) allowed the different vascular components of Total deltaHb(diff) (ECA deltaHb(diff) and ICA deltaHb(diff)) to be identified. Data obtained in 76 patients were deemed suitable. A good correlation between %deltaFV and ICA deltaHb(diff) (r = 0.73, p < 0.0001) was evident. Sixteen patients (21%) fulfilled the criteria for SCI. All patients who demonstrated an ICA deltaHb(diff) of greater than 6.8 micromol/L showed SCI, and in two patients within this group nondisabling watershed infarction developed, as seen on postoperative computerized tomography scans. No patient with an ICA deltaHb(diff) less than 5 micromol/L exhibited SCI or suffered a stroke. Within the resolution of the criteria used an ICA deltaHb(diff) threshold of 6.8 micromol/L provided 100% specificity for SCI, whereas an ICA deltaHb(diff) less than 5 micromol/L was 100% sensitive for excluding SCI. When Total deltaHb(diff) was used without removing the ECA component, no thresholds for SCI were apparent. CONCLUSIONS Carotid endarterectomy provides a stable environment for exploring NIRS-quantified thresholds for SCI in the adult head.
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Affiliation(s)
- P J Kirkpatrick
- MRC Cambridge Centre for Brain Repair and Academic Neurosurgical Unit, Addenbrooke's Hospital and University of Cambridge, United Kingdom
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Pringle J, Art T, Lekeux P. Near infrared spectroscopy for non-invasive assessment of intracranial haemoglobin oxygenation in an in vitro model of the calf head. Res Vet Sci 1998; 65:103-9. [PMID: 9839886 DOI: 10.1016/s0034-5288(98)90159-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in vitro model of the calf head was used to examine the ability of near infrared spectroscopy (NIRS) to non-invasively determine oxygenation events within the calf head. The brains were removed from 16 calf skulls and replaced with oxygenated dilutions of calf blood that had the oxygen progressively decreased from PO2 > 110 mmHg to < 10 mmHg. Appropriate placement of the lighting source and sensor (optodes) was examined, as were the influences of skull thickness and overlying skin of the skull (including colour). The changes in haemaglobin oxygenation in the model calf head, as observed by NIRS, were highly correlated to PO2 changes in all 16 calf skulls examined (mean r2=0.91, range 0.71 to 0.99). There was a trend for optode positioning to achieve optimal NIRS signals over the middle of the frontal bone in a longitudinal axis and with optodes spaced 4 cm apart, but with the large variation between calf heads this was not shown to be significantly different from other sites tested. The presence of skin over the skull had a significant damping effect on the NIRS signal when compared with the bare skull (P<0.01) but it was not possible to detect a difference in this damping effect between black and white coloured skin. All but the two thickest skulls (13 and 14 mm frontal bone thickness) appeared to allow sufficiently strong NIRS signals of changes in haemoglobin oxygenation. This study showed that NIRS can be used for non-invasive study of oxygenation events within the cranial cavity of calves, and established some guidelines and limitations for its use in this species.
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Affiliation(s)
- J Pringle
- Service de Physiologie, Faculté de Médecine Vétérinaire, University of Liège, Belgium.
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Germon TJ, Evans PD, Manara AR, Barnett NJ, Wall P, Nelson RJ. Sensitivity of near infrared spectroscopy to cerebral and extra-cerebral oxygenation changes is determined by emitter-detector separation. J Clin Monit Comput 1998; 14:353-60. [PMID: 9951761 DOI: 10.1023/a:1009957032554] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To examine the effect of two emitter-detector separations (2.7 and 5.5 cm) on the detection of changes in cerebral and extra-cerebral tissue oxygenation using near infrared spectroscopy (NIRS). METHODS Two NIR detectors were placed on the scalp 2.7 and 5.5 cm from a single NIR emitter. Changes in deoxyhaemoglobin (HHb), oxyhaemoglobin (O2Hb),oxidised cytochrome C oxidase (Cyt) and total haemoglobin (tHb) were recorded from each detector during the induction of cerebral oligaemia (transition from hypercapnia to hypocapnia) and scalp hyperaemia (following release of a scalp tourniquet). RESULTS Cerebral oligaemia (mean decrease in middle cerebral artery blood flow velocity of 44%) induced by a mean reduction in end tidal CO2 of 18 mmHg was accompanied by a significant increase in the spectroscopic signal for HHb and a decrease in the O2Hb signal. The signal change per unit photon path length detected at 5.5 cm was significantly greater for HHb (p = 0.007) than that detected at 2.7 cm. In contrast, the increase in all chromophores detected at 5.5 cm during scalp hyperaemia was significantly less than that detected at 2.7 cm (p<0.001). CONCLUSIONS The differing sensitivity of the proximal and distal channels to changes in cerebral and extracerebral oxygenation is compatible with theoretical models of NIR light transmission in the adult head and may provide a basis for spatially resolving these changes. The optimal emitter-detector separation for adult NIRS requires further investigation and may differ between individuals.
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Affiliation(s)
- T J Germon
- Department of Neurosurgery, Frenchay Hospital, Bristol, UK
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Kampfl A, Pfausler B, Denchev D, Jaring HP, Schmutzhard E. Near infrared spectroscopy (NIRS) in patients with severe brain injury and elevated intracranial pressure. A pilot study. ACTA NEUROCHIRURGICA. SUPPLEMENT 1998; 70:112-4. [PMID: 9416295 DOI: 10.1007/978-3-7091-6837-0_35] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Near infrared spectroscopy (NIRS) was used to asses changes in regional cerebral oxygen saturation (rSO2) in 8 head injured patients with an intracranial pressure (ICP) higher or lower than 25 mmHg (n = 4 for each group). NIRS values in the high ICP group (> 25 mmHg) were significantly lower than in the low ICP group (< 25 mmHg). In contrast, arterial pO2, pCO2, peripheral oxygen saturation and transcranial Doppler sonography (TCD) values were similar in both groups. To further investigate changes in rSO2 to changes in peripheral oxygen saturation and arterial pO2, patients of both groups underwent an artificial hyperoxygenation (50% O2) period of 3 minutes. Both groups revealed similar values in peripheral oxygen saturation, arterial pO2, and TCD velocities at the end of the hyperoxygenation period. However, rSO2 values in patients with an ICP > 25 mmHg were significant lower than in patients with an ICP < 25 mmHg after the hyperoxygenation period. In addition, patients with an ICP < 25 mmHg revealed a significant increase in rSO2 values at the end of the hyperoxygenation period, not detectable in patients with an ICP > 25 mmHg. Our results suggest that NIRS may be an additional diagnostic tool in the non-invasive evaluation of impaired cerebral microcirculation in patients with increased intracranial pressure.
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Affiliation(s)
- A Kampfl
- Department of Neurology, University Hospital Innsbruck, Austria
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35
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Duffy CM, Manninen PH, Chan A, Kearns CF. Comparison of cerebral oximeter and evoked potential monitoring in carotid endarterectomy. Can J Anaesth 1997; 44:1077-81. [PMID: 9350367 DOI: 10.1007/bf03019229] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE To assess the cerebral oximeter, which measures regional oxygen saturation (rSO2) continuously and noninvasively, as a cerebral monitor during carotid endarterectomy (CEA). The rSO2 was compared with Somatosensory Evoked Potentials (SSEPs) as an indicator for shunting and as a predictor of postoperative neurological deficits. METHODS Seventy-two consenting patients undergoing CEA with general anaesthesia were studied. Normocarbia, normothermia and normotension were maintained. Cerebral monitoring consisted of bilateral median nerve SSEPs and the INVOS 3100 cerebral oximeter with the sensor pad placed on the ipsilateral forehead. Decreases in SSEP amplitude of 50% and in rSO2 of 10% were considered clinically significant. Neurological assessment was performed at emergence from anaesthesia, 24 hr postoperatively and at discharge. The rSO2 changes were compared with SSEP changes and with neurological deficits. Statistical analysis was with chi square and analysis of variance P < 0.05 was considered significant. RESULTS During carotid artery clamping, rSO2 decreased from 72 +/- 8% to 68 +/- 9% and mean arterial blood pressure increased from 92 +/- 14 mmHg to 98 +/- 14 mmHg. In four patients, the carotid artery was shunted because of SSEP changes after cross-clamping. Five patients had > or = 10% decreases in rSO2 following clamp application. Changes in both SSEP and rSO2 occurred in two patients. Three of the four shunted patients had transient postoperative neurological deficits. One patients had a transient deficit without changes in either monitor. There were no persistent postoperative deficits. Compared with SSEPs, rSO2 had a sensitivity of 50% and a specificity of 96%. CONCLUSION Clinical experience with this evolving technology is ongoing. Its role in neurovascular procedures has yet to be established.
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Affiliation(s)
- C M Duffy
- Department of Anaesthesia, University of Toronto, Toronto Hospital, Ontario
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Abstract
Brain activity is associated with changes in optical properties of brain tissue. Optical measurements during brain activation can assess haemoglobin oxygenation, cytochrome-c-oxidase redox state, and two types of changes in light scattering reflecting either membrane potential (fast signal) or cell swelling (slow signal), respectively. In previous studies of exposed brain tissue, optical imaging of brain activity has been achieved at high temporal and microscopical spatial resolution. Now, using near-infrared light that can penetrate biological tissue reasonably well, it has become possible to assess brain activity in human subjects through the intact skull non-invasively. After early studies employing single-site near-infrared spectroscopy, first near-infrared imaging devices are being applied successfully for low-resolution functional brain imaging. Advantages of the optical methods include biochemical specificity, a temporal resolution in the millisecond range, the potential of measuring intracellular and intravascular events simultaneously and the portability of the devices enabling bedside examinations.
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Affiliation(s)
- A Villringer
- Neurologische Klinik, Charité, Humboldt-Universität Berlin, Germany
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Gomersall CD, Joynt GM, Gin T, Freebairn RC, Stewart IE. Failure of the INVOS 3100 cerebral oximeter to detect complete absence of cerebral blood flow. Crit Care Med 1997; 25:1252-4. [PMID: 9233756 DOI: 10.1097/00003246-199707000-00031] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- C D Gomersall
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT
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Lam JM, Smielewski P, al-Rawi P, Griffiths P, Pickard JD, Kirkpatrick PJ. Internal and external carotid contributions to near-infrared spectroscopy during carotid endarterectomy. Stroke 1997; 28:906-11. [PMID: 9158623 DOI: 10.1161/01.str.28.5.906] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND PURPOSE The internal carotid (ICA) and external carotid (ECA) contributions to changing concentrations of oxyhemoglobin (Hbo2) and deoxyhemoglobin (Hb) during carotid endarterectomy were assessed with the use of near-infrared spectroscopy (NIRS). METHODS NIRS optodes were placed on the forehead with an interoptode distance of 6 cm, and laser-Doppler flowmetry (LDF) was used to monitor the change in skin blood flow between the optodes. Hb, Hbo2, LDF, arterial blood pressure, and middle cerebral artery flow velocity were recorded continuously. The ECA was clamped 2 minutes before the ICA was clamped. Suitable multimodal recordings were achieved in 44 patients. RESULTS When the ECA was clamped, 76% of patients showed a fall in Hbo2 and 65% an increase in Hb. When corrected for changes in arterial blood pressure, an accompanying fall in cutaneous LDF predicted the fall in Hbo2 with high sensitivity (100%) and specificity (100%). Among those with no NIRS changes during ECA clamping, 56% had severe ECA stenosis or occlusion; none of these showed an accompanying fall in LDF. In contrast, when the ICA was clamped, substantial additional changes in NIRS occurred in 55% of cases, all of which were associated with a fall in flow velocity, but none with a change in LDF. Patients with a constant flow velocity after ICA clamping also showed no change in NIRS. CONCLUSIONS Both the ECA and ICA vascular territories contribute to NIRS changes during carotid endarterectomy. The external carotid contribution to NIRS can be monitored with cutaneous LDF.
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Affiliation(s)
- J M Lam
- Medical Research Council Cambridge Center for Brain Repair, Addenbrooke's Hospital, UK
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Smielewski P, Czosnyka M, Pickard JD, Kirkpatrick P. Clinical evaluation of near-infrared spectroscopy for testing cerebrovascular reactivity in patients with carotid artery disease. Stroke 1997; 28:331-8. [PMID: 9040685 DOI: 10.1161/01.str.28.2.331] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE Near-infrared spectroscopy (NIRS) derives information about the concentrations of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) from measurements of light attenuation caused by these chromosphores. The aim of this study was to assess NIRS as a tool for testing CO2 reactivity in patients with carotid artery disease. METHODS One hundred patients with symptomatic carotid occlusive disease were examined (age range, 44 to 83 years). The severity of stenosis ranged from 30% to 100% (median, 80%) on the ipsilateral side and 0% to 100% (median, 30%) on the contralateral side. Monitored parameters included transcranial Doppler flow velocity, changes in concentration of HbO2 and Hb, cutaneous laser-Doppler blood flow, endtidal CO2, arterial blood pressure, and arterial oxygen saturation. Hypercapnia was induced with the use of a 5% CO2/air mixture for inhalation. To estimate the contribution of skin flow to NIRS during reactivity testing, the superficial temporal artery was compressed, and the NIRS changes in response to the fall in laser-Doppler blood flow were recorded. Finally, reproducibility of reactivity testing was assessed in 10 patients who were subjected to repeated examinations over 3 days. RESULTS Flow velocity- and HbO2-derived reactivity values were related to the severity of the stenosis (P = .0001 and P = .017, respectively). The correlation between the two reactivity modalities was significant (r = .49, P < .000001). The median estimated contribution of skin flow to NIRS changes was 15.8%. Another variable affecting HbO2 signal changes during the CO2 challenge was arterial blood pressure (P = .025). Reproducibility of HbO2 reactivity was similar to flow velocity reactivity (14.3% and 18.6% variation, respectively). CONCLUSIONS NIRS shows potential as an alternative technique for testing CO2 reactivity in patients with carotid disease provided that conditions are carefully controlled. Marked changes in arterial blood pressure may render the NIRS reactivity indices unreliable, and the contribution from extracranial tissue must be taken into account when significant.
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Affiliation(s)
- P Smielewski
- Medical Research Council Cambridge Center for Brain Repair and Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge UK
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Holzschuh M, Woertgen C, Metz C, Brawanski A. Comparison of changes in cerebral blood flow and cerebral oxygen saturation measured by near infrared spectroscopy (NIRS) after acetazolamide. Acta Neurochir (Wien) 1997; 139:58-62. [PMID: 9059713 DOI: 10.1007/bf01850869] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The present study compares the change of cerebral blood flow and HbO2 measured by near-infrared spectroscopy (NIRS) after administration of 1000 mg acetazolamide intravenously. CBF studies in 21 patients with ischaemic cerebrovascular disease were performed routinely with the 133Xenon technique. Additionally the local HbO2 was recorded by NIRS. A rest study was followed by a second study after the administration of 1000 mg acetazolamide. In 18 patients we observed an increase of 30.8% of CBF and 4.7% of HbO2, 3 patients showed a decrease of CBF and 2 patients a simultaneous decrease of HbO2. We did not find a correlation between the absolute values of CBF and HbO2 at rest or after stimulation. However, a positive correlation (r = 0.71, p < 0.05) between the change of CBF and HbO2 could be detected. Assuming a threshold value of normal CBF reactivity of 30% and 4% HbO2 reactivity we found for NIRS a sensitivity of 0.88 and a specificity of 0.75. The results demonstrate that changes of CBF can be detected with NIRS and the algorithm of the used monitor is able to calculate the intracranial part of the signal. So, NIRS can be used as non-invasive screening method to test the cerebrovascular reserve capacity.
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Affiliation(s)
- M Holzschuh
- Department of Neurosurgery, University of Regensburg, Federal Republic of Germany
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DUNCAN L, WlLDSMITH J, RUCKLEY C. Near infrared spectroscopy. Anaesthesia 1996. [DOI: 10.1111/j.1365-2044.1996.tb04670.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Owen-Reece H, Elwell CE, Wyatt JS, Delpy DT. The effect of scalp ischaemia on measurement of cerebral blood volume by near-infrared spectroscopy. Physiol Meas 1996; 17:279-86. [PMID: 8953626 DOI: 10.1088/0967-3334/17/4/005] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Near-infrared spectroscopy (NIRS) is a noninvasive method of quantifying changes in cerebral haemodynamics from changes in the absorption of near-infrared light by oxyhaemoglobin and deoxyhaemoglobin. Measurement of neonatal cerebral blood volume (CBV) by NIRS was described in 1990 but it has been suggested that, in adults, scalp and skull blood content contribute a significant amount to the cerebral haemodynamic variables quantifiable by NIRS. To investigate this, CBV was measured in nine adult subjects, in the frontal region of the head, before and after inflating a pneumatic tourniquet proximal to the measurement site. Because a change in scalp blood content could potentially alter the pathlength of light passing through the head and hence affect the measured CBV, the optical pathlength factor was therefore also measured before and after tourniquet inflation. Blood flow occlusion was confirmed by laser Doppler velocimetry. The results showed that tourniquet inflation had no effect on the estimated value of CBV or the differential pathlength factor. We conclude that, provided the distance between light entry and exit on the surface of the scalp is sufficiently large, changes in scalp blood flow have no effect on NIRS measurement of cerebral haemodynamics.
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Affiliation(s)
- H Owen-Reece
- Department of Anaesthesia, National Hospital for Neurology and Neurosurgery, London, UK
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Williams IM, Mortimer AJ, McCollum CN. Recent developments in cerebral monitoring--near-infrared light spectroscopy. An overview. Eur J Vasc Endovasc Surg 1996; 12:263-71. [PMID: 8896467 DOI: 10.1016/s1078-5884(96)80243-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A recent development has been the resurgence of interest in the concept of near-infrared light spectroscopy as a method of monitoring cerebral perfusion. Although this technique has been in use for 40 years, the principle has been primarily employed in peripheral pulse oximetry. Infrared light of wavelengths 600-1300 nanometres (nm) penetrate human tissue to a depth of several centimetres. Within the human brain this light is attenuated by the chromophores oxyhaemoglobin, deoxyhaemoglobin and also oxidised cytochrome a3. Positioning a near-infrared light source and a photodetector in a side by side configuration detects light attenuated and reflected in a parabolic path through the scalp, skull and brain tissue.
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Affiliation(s)
- I M Williams
- Department of Surgery, University Hospital of South Manchester, West Didsbury, Manchester, U.K
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46
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Near-Infrared Spectroscopy. J Neurosurg 1996. [DOI: 10.3171/jns.1996.85.2.0363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
In conclusion, NIRS appears to offer both a new monitoring modality and new information about cerebral oxygenation. Technical problems in the application of this technology persist, most notably determination of pathlength and the volume of tissue interrogated. Those familiar with the history of pulse oximetry will recall that although Millikan developed an ear oximeter in 1947, it was not until Aoyagi combined recognition of the pulse signal with spectroscopy in the 1970s that oximetry was transformed into a clinically applicable monitor. In much the same way, NIRS may find the same tremendous usefulness as a noninvasive monitor of cerebral oxygen utilization, pending resolution of the remaining technical problems.
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Affiliation(s)
- J A Wahr
- Department of Anesthesiology, University of Michigan, Ann Arbor, USA
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Lane NJ, Thorniley MS, Manek S, Fuller BJ, Green CJ. Hemoglobin oxygenation kinetics and secondary ischemia in renal transplantation. Transplantation 1996; 61:689-96. [PMID: 8607168 DOI: 10.1097/00007890-199603150-00003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The significance of poor medullary reperfusion in the etiology of acute tubular necrosis during renal transplantation is poorly understood. Our objective was to determine the kinetics of renal hemoglobin oxygenation using near-infrared spectroscopy during renal transplantation, to provide a framework against which the timing of mitochondrial dysfunction could be considered. New Zealand White rabbit kidneys were flushed with hypertonic citrate solution (0-2 degrees C and autografted immediately (group 1) or stored at 0-2 degrees C for 72 hours before autografting (group 2). Changes in oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) were monitored by near-infrared spectroscopy for 3 hours of reperfusion. Intrarenal perfusion was evaluated separately by barium sulfate angiography. Reperfusion resulted in rapid increases in HbO2 within 1 minute in both groups. Group 1 HbO2 fell sharply to a minimum at 3 minutes but recovered by 20 minutes; group 2 changes were similar, but there was no recovery (P<0.05 by 10 minutes). Hb increased rapidly in both groups upon reperfusion but in group 2 was significantly greater after 10 minutes (P<0.05). Total hemoglobin levels were similar in both groups. Renal hemoglobin saturation was 69% at 1 minute in both groups; there was no significant change in group 1 but a profound desaturation in group 2 to 25% at 10 minute (P<0.005) and no recovery thereafter. Barium sulfate distribution was normal in all group 1 kidneys; cortical distribution was normal in all group 2 kidneys, but medullary perfusion was poor for the first 60 minutes. Renal hemoglobin oxygenation kinetics as determined here do not correlate with the timing of mitochondrial dysfunction previously reported (Thorniley et al., Kidney International, 1994; 45: 1489). We conclude that secondary ischemia during reflow is not the only mechanism leading to acute tubular necrosis.
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Affiliation(s)
- N J Lane
- Department of Surgical Research, Northwick Park Institute for Medical Research, Northwick Park Hospital, Harrow, United Kingdom
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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. [PMID: 8561326 DOI: 10.1097/00000539-199602000-00010] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cerebral oximeters based on near-infrared spectroscopy may provide a continuous, noninvasive assessment of cerebral oxygenation. We evaluated a prototype cerebral oximeter (Invos 3100; Somanetics, Troy, MI) in 22 conscious, healthy volunteers breathing hypoxic gas mixtures. Using the first 12 subjects (training group), we developed an algorithm based on the mathematic relationship that converts detected light from the field surveyed by the probe to cerebral hemoglobin oxygen saturation (CSfO2). To develop the algorithm, we correlated the oximeter result with the estimated combined brain hemoglobin oxygen saturation (CScombO2, where CScombO2 = SaO2 x 0.25 + SjO2 x 0.75 and SjO2 = jugular venous saturation). We then validated the algorithm in the remaining 10 volunteers (validation group). A close association (r2 = 0.798-0.987 for individuals in the training group and r2 = 0.794-0.992 for individuals in the validation group) existed between CSfO2 and CScombO2. We conclude that continuous monitoring with cerebral oximetry may accurately recognize decreasing cerebral hemoglobin oxygen saturation produced by systemic hypoxemia.
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Affiliation(s)
- V Pollard
- Department of Anesthesiology, University of Texas Medical Branch, Galveston 77555-0591, USA
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