Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow

F. W. Leung, S. K. Lo, Q. Q. Phan, Joseph Leung, G. S. Yanni, J. Jing

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probewere varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10% dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90° to 60° did not affect ISO2 or IHB measurements. At 45°, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10% dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.

Original languageEnglish (US)
Pages (from-to)18-21
Number of pages4
JournalGastrointestinal Endoscopy
Volume41
Issue number1
DOIs
StatePublished - 1995
Externally publishedYes

Fingerprint

Hemoglobins
Oxygen
Spectrophotometry
Light
Controlled Hypotension
Glucose
Hyperemia
Mouth Mucosa
Gastric Mucosa
Hypotension
Lung Diseases
Fingers
Colon
Mucous Membrane
Chronic Disease
Ischemia
Clinical Studies

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow. / Leung, F. W.; Lo, S. K.; Phan, Q. Q.; Leung, Joseph; Yanni, G. S.; Jing, J.

In: Gastrointestinal Endoscopy, Vol. 41, No. 1, 1995, p. 18-21.

Research output: Contribution to journalArticle

Leung, F. W. ; Lo, S. K. ; Phan, Q. Q. ; Leung, Joseph ; Yanni, G. S. ; Jing, J. / Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow. In: Gastrointestinal Endoscopy. 1995 ; Vol. 41, No. 1. pp. 18-21.
@article{ac405e694c5840908f360687c9af7187,
title = "Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow",
abstract = "Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probewere varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10{\%} dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90° to 60° did not affect ISO2 or IHB measurements. At 45°, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10{\%} dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.",
author = "Leung, {F. W.} and Lo, {S. K.} and Phan, {Q. Q.} and Joseph Leung and Yanni, {G. S.} and J. Jing",
year = "1995",
doi = "10.1016/S0016-5107(95)70271-7",
language = "English (US)",
volume = "41",
pages = "18--21",
journal = "Gastrointestinal Endoscopy",
issn = "0016-5107",
publisher = "Mosby Inc.",
number = "1",

}

TY - JOUR

T1 - Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow

AU - Leung, F. W.

AU - Lo, S. K.

AU - Phan, Q. Q.

AU - Leung, Joseph

AU - Yanni, G. S.

AU - Jing, J.

PY - 1995

Y1 - 1995

N2 - Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probewere varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10% dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90° to 60° did not affect ISO2 or IHB measurements. At 45°, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10% dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.

AB - Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probewere varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10% dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90° to 60° did not affect ISO2 or IHB measurements. At 45°, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10% dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.

UR - http://www.scopus.com/inward/record.url?scp=0028906522&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028906522&partnerID=8YFLogxK

U2 - 10.1016/S0016-5107(95)70271-7

DO - 10.1016/S0016-5107(95)70271-7

M3 - Article

C2 - 7698620

AN - SCOPUS:0028906522

VL - 41

SP - 18

EP - 21

JO - Gastrointestinal Endoscopy

JF - Gastrointestinal Endoscopy

SN - 0016-5107

IS - 1

ER -