Have a personal or library account? Click to login
Comparison of cerebrovascular reactivity tests: a pilot human study Cover

Comparison of cerebrovascular reactivity tests: a pilot human study

Journal of Electrical Bioimpedance
Volume 8 (2017): Issue 1 (January 2017)
By: Michael Bodo,  Richard Mahon,  Alex Razumovsky,  Efim Kouperberg,  Michael Crimmins,  Rocco Armonda and  Martin Baruch  
Open Access
|May 2017

Figures & Tables

Fig. 1

Recording of a REG (red) and NIRS (blue) signals during sequence of tests (upper panel). Lower panel shows same REG signal and event markers indicating when a test started and ended (blue). Tests are as: breath holding, hyperventilation, CO2 inhalation, Valsalva maneuver, Trendelenburg and Reverse Trendelenburg positions. Y-axis is in AD conversion units; X-axis is in seconds. Note the simultaneous amplitude increase of REG and NIRS signals during Trendelenburg position (1750-2000 s).
Recording of a REG (red) and NIRS (blue) signals during sequence of tests (upper panel). Lower panel shows same REG signal and event markers indicating when a test started and ended (blue). Tests are as: breath holding, hyperventilation, CO2 inhalation, Valsalva maneuver, Trendelenburg and Reverse Trendelenburg positions. Y-axis is in AD conversion units; X-axis is in seconds. Note the simultaneous amplitude increase of REG and NIRS signals during Trendelenburg position (1750-2000 s).

Fig. 2

Breath holding. REG (red) and NIRS (blue) signals during breath holding (see 350-380 seconds: breath holding is indicated by light blue vertical lines). REG and NIRS amplitude increases were simu1taneous: 20.2 % of baseline (after test). (Y-axis values are shown in AD conversion units; X-axis values are shown in seconds).
Breath holding. REG (red) and NIRS (blue) signals during breath holding (see 350-380 seconds: breath holding is indicated by light blue vertical lines). REG and NIRS amplitude increases were simu1taneous: 20.2 % of baseline (after test). (Y-axis values are shown in AD conversion units; X-axis values are shown in seconds).

Fig. 3

Hyperventilation. REG signal after filtering during 30 sec hyperventilation (upper trace), EtCO2 (middle trace), NIRS (lower trace). REG amplitude gradually increased during the test as NIRS synchronously decreased. (Y-axis values are shown in AD conversion units; X-axis values are shown in seconds).
Hyperventilation. REG signal after filtering during 30 sec hyperventilation (upper trace), EtCO2 (middle trace), NIRS (lower trace). REG amplitude gradually increased during the test as NIRS synchronously decreased. (Y-axis values are shown in AD conversion units; X-axis values are shown in seconds).

Fig. 4

CO2 inhalation. REG signal (red) after filtering; NIRS (blue). Time of inhalation indicated by vertical lines (blue). REG amplitude increase was 179.23 % of baseline (before test), in identical time with NIRS. Y-axis is AD conversion units; X-axis is in seconds.
CO2 inhalation. REG signal (red) after filtering; NIRS (blue). Time of inhalation indicated by vertical lines (blue). REG amplitude increase was 179.23 % of baseline (before test), in identical time with NIRS. Y-axis is AD conversion units; X-axis is in seconds.

Fig. 5

NIRS, REG and TCD during tests. Data are as percent of baseline (mean + SD). Tests are as BH: breath holding; HV: hyperventilation; CO2: CO2 inhalation; Valsalva: Valsalva maneuver; TREN: Trendelenburg and R TREN: Reverse Trendelenburg positions.
NIRS, REG and TCD during tests. Data are as percent of baseline (mean + SD). Tests are as BH: breath holding; HV: hyperventilation; CO2: CO2 inhalation; Valsalva: Valsalva maneuver; TREN: Trendelenburg and R TREN: Reverse Trendelenburg positions.

Fig. 6

Note the decrease of LDF flux signal during Trendelenburg position (1700-2050 sec). Also shown: LDF flux (red) and NIRS (blue) signals during all tests (purple). Y-axis is in AD conversion units; X-axis is in seconds.
Note the decrease of LDF flux signal during Trendelenburg position (1700-2050 sec). Also shown: LDF flux (red) and NIRS (blue) signals during all tests (purple). Y-axis is in AD conversion units; X-axis is in seconds.

Summary of tests and responses by modalities: BH (breath holding); HV (hyperventilation); CO2 (CO2 inhalation); VAL: Valsalva maneuver; TREN (Trendelenburg position); R TREN (reverse Trendelenburg position); N (number of measured subjects)_ In case of NIRS and TCD Trendelenburg measurement showed multyphasic change, not just increase or decrease in 7 (NIRS) and 10 cases (TCD)_ Exceptions: *LDF increased; **LDF decreased; NIRS and TCD showed multiphasic reactions for Trendelenburg and reverse Trandelenburg positions_

BH increaseHV decreaseCO2 increaseVAL increaseTREN increaseRTREN decreaseTotal testsFailed testsFailed tests (%)N
NIRS1113121113127867.713
TCD998930602236.710
REG17913161415721419.412
LDF8(7)*711(9**)8722230.612

Result of one-way analysis of variance of NIRS, TCD and REG during breath holding, hyperventilation and CO2 inhalation_

P value:0.2059
P value summary:ns
Are means signif. different? (P < 0.05):No
Number of groups:3
F:1.661
R squared:0.09406
Bartlett's test for equal variances:
Bartlett's statistic (corrected):53.3
P value:P<0.0001
P value summary:***
Do the variances differ signif. (P < 0.05):Yes
ANOVA Table:SSdfMS
Treatment (between columns):653.82326.9
Residual (within columns):629732196.8
Total:695034

Epidemiology of test subjects; n=14; mean (upper numerical row) and SD values (lower numerical row)_ The differences between left and right systolic and diastolic values were not significant_ *Body Mass Index_ Protocols were approved by an Institutional Review Board_

Left ArmRight Arm
Age yearWeight kgHeight cmBMI* kg/m2Systolic mmHgDiastolic mmHgSystolic mmHgDiastolic mmHgHeart Rate b/m
31.683.9174.327.5123.074.0124.873.766.6
7.115.88.64.08.85.77.56.210.6
DOI: https://doi.org/10.5617/jeb.3939 | Journal eISSN: 1891-5469
Journal RSS Feed
Language: English
Page range: 25 - 33
Submitted on: Nov 15, 2016
Published on: May 7, 2017
Published by: University of Oslo
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
cerebrovascular reactivity,
REG,
TCD,
NIRS,
LDF,
human
Related subjects:
Engineering,
Bioengineering and biomedical engineering,
Biomedical electronics,
Life sciences,
Biophysics,
Medicine,
Biomedical engineering,
Physics,
Spectroscopy and metrology

© 2017 Michael Bodo, Richard Mahon, Alex Razumovsky, Efim Kouperberg, Michael Crimmins, Rocco Armonda, Martin Baruch, published by University of Oslo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Previous articleVolume 8 (2017): Issue 1 (January 2017)Next article