eprintid: 2473
rev_number: 10
eprint_status: archive
userid: 151
dir: disk0/00/00/24/73
datestamp: 2007-03-14 12:00:00
lastmod: 2015-07-23 09:33:23
status_changed: 2008-01-09 13:38:51
type: article
metadata_visibility: show
creators_name: Tachtsidis, I.
creators_name: Tisdall, M.
creators_name: Leung, T.S.
creators_name: Cooper, C.E.
creators_name: Delpy, D.T.
creators_name: Smith, M.
creators_name: Elwell, C.E.
creators_id: ITACH19
creators_id: MMTIS18
creators_id: TSTLE21
creators_id: CECOO61
creators_id: 
creators_id: MSMIT43
creators_id: CEELW72
title: Investigation of in vivo measurement of cerebral cytochrome-c-oxidase redox changes using near-infrared spectroscopy in patients with orthostatic hypotension
ispublished: pub
subjects: 8400
subjects: 25600
divisions: F42
divisions: F82
keywords: near-infrared spectroscopy, cytochrome c oxidase, cerebral oxygenation, autonomic failure
abstract: We have previously used a continuous four wavelength near infrared spectrometer to measure changes in the cerebral concentrations of oxy- (Δ[HbO2] and deoxy- haemoglobin (Δ[HHb]) during head-up tilt in patients with primary autonomic failure. The measured changes in light attenuation also allow calculation of changes in the concentration of oxidised cytochrome c oxidase (Δ[oxCCO]), and this  paper analyses the Δ[oxCCO] during the severe episodes of orthostatic hypotension produced by this experimental protocol. We studied 12 patients during a passive change in position from supine to a 60º head-up tilt. The challenge caused a reduction in mean blood pressure of 59.93 (±26.12) mmHg (Mean (±SD), p<0.0001), which was associated with a reduction in the total concentration of haemoglobin (Δ[HbT]= Δ[HbO2]+Δ[HHb]) of 5.02 (±3.81) μM  (p<0.0001) and a reduction in the haemoglobin difference concentration  (Δ[Hbdiff]= Δ[HbO2]-Δ[HHb]) of 14.4 (±6.73) μM  (p<0.0001). We observed a wide range of responses in Δ[oxCCO]. 6 patients demonstrated a drop in Δ[oxCCO] (0.17 ±0.15μM ); 4 patients demonstrated no change (0.01 ±0.12 μM ) and 2 patients showed an increase in Δ[oxCCO] (0.21 ±0.01 μM ). Investigation of the association between the changes in concentrations of haemoglobin species and the Δ[oxCCO] for each patient show a range of  relationships. This suggests that a simple mechanism for crosstalk, which might produce artefactual changes in [oxCCO], is not present between the haemoglobin and the oxCCO NIRS signals. Further investigation is required to determine the clinical significance of the changes in [oxCCO].
date: 2007
date_type: published
official_url: http://dx.doi.org/10.1088/0967-3334/28/2/008
vfaculties: VENG
vfaculties: VFBRS
rae2008: 19
oa_status: green
language: eng
primo: open
primo_central: open_green
doi: 10.1088/0967-3334/28/2/008
lyricists_name: Tachtsidis, I
lyricists_name: Tisdall, M
lyricists_name: Leung, T
lyricists_name: Cooper, C
lyricists_id: ITACH19
lyricists_id: MMTIS18
lyricists_id: TSTLE21
lyricists_id: CECOO61
full_text_status: public
publication: Physiological Measurement
volume: 28
number: 2
pagerange: 198-211
refereed: TRUE
issn: 0967-3334
citation:        Tachtsidis, I.;    Tisdall, M.;    Leung, T.S.;    Cooper, C.E.;    Delpy, D.T.;    Smith, M.;    Elwell, C.E.;      (2007)    Investigation of in vivo measurement of cerebral cytochrome-c-oxidase redox changes using near-infrared spectroscopy in patients with orthostatic hypotension.                   Physiological Measurement , 28  (2)   pp. 198-211.    10.1088/0967-3334/28/2/008 <https://doi.org/10.1088/0967-3334%2F28%2F2%2F008>.       Green open access   
 
document_url: https://discovery-pp.ucl.ac.uk/id/eprint/2473/1/2473.pdf