Cerebral arterial and venous contributions to tissue oxygenation index measured using spatially resolved spectroscopy in newborn lambs

Flora Wong, Theodora Alexiou, Thilini Samarasinghe, Vojta Brodecky, Adrian Walker

Research output: Contribution to journalArticleResearchpeer-review

Abstract

BACKGROUND: Bedside assessments of cerebral oxygenation are sought to monitor cerebral injury in patients undergoing intensive care. Spatially resolved spectroscopy measures tissue oxygenation index (TOI, ) which reflects mixed cerebral arterial and venous oxygenations. We aimed to evaluate arterial and venous components of TOI (cerebral arterial to venous volume ratio [A:V ratio]) in the newborn lamb brain using cerebral arterial and venous blood samples, and to investigate the impact of acute hypoxemia on the A:V ratio and TOI. METHOD: Nine lambs were ventilated with varied inspired oxygen to generate arterial oxygen saturations between 25 and 100 . Cerebral arterial and venous oxygen saturations analyzed using cooximeter of arterial and superior sagittal sinus blood were used to estimate TOI (TOIcox), assuming cerebral A:V ratio of 25:75. TOIcox was compared with the TOI measured by spatially resolved spectroscopy (TOIsrs). Actual cerebral arterial and venous volume fractions were reestimated using TOIsrs = cerebral arterial volume fraction cerebral arterial oxygen saturation + cerebral venous volume fraction*cerebral venous oxygen saturation. RESULTS: Median (range) TOIsrs was 48.5 (32.0-64.1 ), and TOIcox was 48.4 (13.7-74.4 ), and the two were significantly correlated (R = 0.77). The mean difference between TOIsrs and TOIcox was 2.4 (limits of agreement +/- 18.1 ). The TOIsrs - TOIcox difference varied with oxygen saturations, with TOIsrs higher than TOIcox at low saturations, and lower at high saturations. Cerebral arterial volume fraction was 22.9-27.5 in normoxia and markedly increased in hypoxemia. CONCLUSION: TOI corresponds with cerebral oxygenation. The variable agreement of TOIsrs with TOIcox may reflect changes in cerebral A:V ratio due to arterial oxygenation-related vasoreactivity.
Original languageEnglish
Pages (from-to)1385 - 1391
Number of pages7
JournalAnesthesiology
Volume113
Issue number6
DOIs
Publication statusPublished - 2010

Cite this

@article{905ca856262d43cf8db6a7918cf474e1,
title = "Cerebral arterial and venous contributions to tissue oxygenation index measured using spatially resolved spectroscopy in newborn lambs",
abstract = "BACKGROUND: Bedside assessments of cerebral oxygenation are sought to monitor cerebral injury in patients undergoing intensive care. Spatially resolved spectroscopy measures tissue oxygenation index (TOI, ) which reflects mixed cerebral arterial and venous oxygenations. We aimed to evaluate arterial and venous components of TOI (cerebral arterial to venous volume ratio [A:V ratio]) in the newborn lamb brain using cerebral arterial and venous blood samples, and to investigate the impact of acute hypoxemia on the A:V ratio and TOI. METHOD: Nine lambs were ventilated with varied inspired oxygen to generate arterial oxygen saturations between 25 and 100 . Cerebral arterial and venous oxygen saturations analyzed using cooximeter of arterial and superior sagittal sinus blood were used to estimate TOI (TOIcox), assuming cerebral A:V ratio of 25:75. TOIcox was compared with the TOI measured by spatially resolved spectroscopy (TOIsrs). Actual cerebral arterial and venous volume fractions were reestimated using TOIsrs = cerebral arterial volume fraction cerebral arterial oxygen saturation + cerebral venous volume fraction*cerebral venous oxygen saturation. RESULTS: Median (range) TOIsrs was 48.5 (32.0-64.1 ), and TOIcox was 48.4 (13.7-74.4 ), and the two were significantly correlated (R = 0.77). The mean difference between TOIsrs and TOIcox was 2.4 (limits of agreement +/- 18.1 ). The TOIsrs - TOIcox difference varied with oxygen saturations, with TOIsrs higher than TOIcox at low saturations, and lower at high saturations. Cerebral arterial volume fraction was 22.9-27.5 in normoxia and markedly increased in hypoxemia. CONCLUSION: TOI corresponds with cerebral oxygenation. The variable agreement of TOIsrs with TOIcox may reflect changes in cerebral A:V ratio due to arterial oxygenation-related vasoreactivity.",
author = "Flora Wong and Theodora Alexiou and Thilini Samarasinghe and Vojta Brodecky and Adrian Walker",
year = "2010",
doi = "10.1097/ALN.0b013e3181fc5567",
language = "English",
volume = "113",
pages = "1385 -- 1391",
journal = "Anesthesiology",
issn = "0003-3022",
publisher = "American Society of Anesthesiologists",
number = "6",

}

Cerebral arterial and venous contributions to tissue oxygenation index measured using spatially resolved spectroscopy in newborn lambs. / Wong, Flora; Alexiou, Theodora; Samarasinghe, Thilini; Brodecky, Vojta; Walker, Adrian.

In: Anesthesiology, Vol. 113, No. 6, 2010, p. 1385 - 1391.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Cerebral arterial and venous contributions to tissue oxygenation index measured using spatially resolved spectroscopy in newborn lambs

AU - Wong, Flora

AU - Alexiou, Theodora

AU - Samarasinghe, Thilini

AU - Brodecky, Vojta

AU - Walker, Adrian

PY - 2010

Y1 - 2010

N2 - BACKGROUND: Bedside assessments of cerebral oxygenation are sought to monitor cerebral injury in patients undergoing intensive care. Spatially resolved spectroscopy measures tissue oxygenation index (TOI, ) which reflects mixed cerebral arterial and venous oxygenations. We aimed to evaluate arterial and venous components of TOI (cerebral arterial to venous volume ratio [A:V ratio]) in the newborn lamb brain using cerebral arterial and venous blood samples, and to investigate the impact of acute hypoxemia on the A:V ratio and TOI. METHOD: Nine lambs were ventilated with varied inspired oxygen to generate arterial oxygen saturations between 25 and 100 . Cerebral arterial and venous oxygen saturations analyzed using cooximeter of arterial and superior sagittal sinus blood were used to estimate TOI (TOIcox), assuming cerebral A:V ratio of 25:75. TOIcox was compared with the TOI measured by spatially resolved spectroscopy (TOIsrs). Actual cerebral arterial and venous volume fractions were reestimated using TOIsrs = cerebral arterial volume fraction cerebral arterial oxygen saturation + cerebral venous volume fraction*cerebral venous oxygen saturation. RESULTS: Median (range) TOIsrs was 48.5 (32.0-64.1 ), and TOIcox was 48.4 (13.7-74.4 ), and the two were significantly correlated (R = 0.77). The mean difference between TOIsrs and TOIcox was 2.4 (limits of agreement +/- 18.1 ). The TOIsrs - TOIcox difference varied with oxygen saturations, with TOIsrs higher than TOIcox at low saturations, and lower at high saturations. Cerebral arterial volume fraction was 22.9-27.5 in normoxia and markedly increased in hypoxemia. CONCLUSION: TOI corresponds with cerebral oxygenation. The variable agreement of TOIsrs with TOIcox may reflect changes in cerebral A:V ratio due to arterial oxygenation-related vasoreactivity.

AB - BACKGROUND: Bedside assessments of cerebral oxygenation are sought to monitor cerebral injury in patients undergoing intensive care. Spatially resolved spectroscopy measures tissue oxygenation index (TOI, ) which reflects mixed cerebral arterial and venous oxygenations. We aimed to evaluate arterial and venous components of TOI (cerebral arterial to venous volume ratio [A:V ratio]) in the newborn lamb brain using cerebral arterial and venous blood samples, and to investigate the impact of acute hypoxemia on the A:V ratio and TOI. METHOD: Nine lambs were ventilated with varied inspired oxygen to generate arterial oxygen saturations between 25 and 100 . Cerebral arterial and venous oxygen saturations analyzed using cooximeter of arterial and superior sagittal sinus blood were used to estimate TOI (TOIcox), assuming cerebral A:V ratio of 25:75. TOIcox was compared with the TOI measured by spatially resolved spectroscopy (TOIsrs). Actual cerebral arterial and venous volume fractions were reestimated using TOIsrs = cerebral arterial volume fraction cerebral arterial oxygen saturation + cerebral venous volume fraction*cerebral venous oxygen saturation. RESULTS: Median (range) TOIsrs was 48.5 (32.0-64.1 ), and TOIcox was 48.4 (13.7-74.4 ), and the two were significantly correlated (R = 0.77). The mean difference between TOIsrs and TOIcox was 2.4 (limits of agreement +/- 18.1 ). The TOIsrs - TOIcox difference varied with oxygen saturations, with TOIsrs higher than TOIcox at low saturations, and lower at high saturations. Cerebral arterial volume fraction was 22.9-27.5 in normoxia and markedly increased in hypoxemia. CONCLUSION: TOI corresponds with cerebral oxygenation. The variable agreement of TOIsrs with TOIcox may reflect changes in cerebral A:V ratio due to arterial oxygenation-related vasoreactivity.

UR - http://www.ncbi.nlm.nih.gov/pubmed/21068664

U2 - 10.1097/ALN.0b013e3181fc5567

DO - 10.1097/ALN.0b013e3181fc5567

M3 - Article

VL - 113

SP - 1385

EP - 1391

JO - Anesthesiology

JF - Anesthesiology

SN - 0003-3022

IS - 6

ER -