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Dark adaptation during systemic hypoxia induced by chronic respiratory insufficiency

Thylefors, Joakim LU orcid ; Piitulainen, Eeva LU and Havelius, Ulf LU (2009) In Investigative Ophthalmology & Visual Science 50(3). p.12-1307
Abstract

PURPOSE: To investigate dark adaptation during hypoxia in patients with chronic respiratory failure.

METHODS: At three visits, dark adaptation was recorded by computerized dark adaptometry in 13 patients with chronic respiratory insufficiency treated by long-term oxygen therapy. At visits 1 and 3, the patients were administered their usual oxygen supplement. At visit 2, no oxygen was given. At each visit, an analysis of arterial blood gases measured pH, partial pressure of O(2) (Pao(2)), partial pressure of CO(2) (Paco(2)), base excess (BE), standard bicarbonate (HCO(3)), and arterial oxygen saturation. Pulse oximetry (POX) was also recorded.

RESULTS: Significant differences were recorded between visits 1 and 2 and between... (More)

PURPOSE: To investigate dark adaptation during hypoxia in patients with chronic respiratory failure.

METHODS: At three visits, dark adaptation was recorded by computerized dark adaptometry in 13 patients with chronic respiratory insufficiency treated by long-term oxygen therapy. At visits 1 and 3, the patients were administered their usual oxygen supplement. At visit 2, no oxygen was given. At each visit, an analysis of arterial blood gases measured pH, partial pressure of O(2) (Pao(2)), partial pressure of CO(2) (Paco(2)), base excess (BE), standard bicarbonate (HCO(3)), and arterial oxygen saturation. Pulse oximetry (POX) was also recorded.

RESULTS: Significant differences were recorded between visits 1 and 2 and between visits 2 and 3 for Pao(2), arterial oxygen saturation, and POX; no differences were found for pH, Paco(2), BE, or HCO(3). No differences were seen between visits 1 and 3 for any of the laboratory parameters. All patients had normal and unchanged dark adaptation at the three visits.

CONCLUSIONS: Hypoxia in chronic respiratory insufficiency was associated with normal dark adaptation, in contrast to hypoxia in healthy persons at high altitudes, which is known to produce impaired dark adaptation. The result may partly reflect the influence of Paco(2) on the lumen of choroidal and retinal vessels. At high altitudes, with hypocapnic vasoconstriction the oxygen supply to the retina is further compromised, resulting in reduced dark adaptation. The authors hypothesize that respiratory insufficiency with hypercapnia or normocapnia will have larger choroidal and retinal vessel lumens, added to by further dilation of retinal vessels during hypoxia. The tentative net effect would be preserved dark adaptation.

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type
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publication status
published
subject
keywords
Aged, Aged, 80 and over, Blood Gas Analysis, Chronic Disease, Dark Adaptation/physiology, Female, Humans, Hydrogen-Ion Concentration, Hypoxia/physiopathology, Male, Middle Aged, Oximetry, Oxygen/therapeutic use, Partial Pressure, Respiratory Insufficiency/physiopathology
in
Investigative Ophthalmology & Visual Science
volume
50
issue
3
pages
6 pages
publisher
Association for Research in Vision and Ophthalmology Inc.
external identifiers
  • wos:000263665000043
  • pmid:18936146
  • scopus:62649105252
  • pmid:18936146
ISSN
1552-5783
DOI
10.1167/iovs.08-2104
language
English
LU publication?
yes
id
a678b1fb-c922-48db-b35e-1ba9464ca09b (old id 1262088)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/18936146?dopt=Abstract
date added to LUP
2016-04-04 09:32:18
date last changed
2021-11-18 10:43:22
@article{a678b1fb-c922-48db-b35e-1ba9464ca09b,
  abstract     = {<p>PURPOSE: To investigate dark adaptation during hypoxia in patients with chronic respiratory failure.</p><p>METHODS: At three visits, dark adaptation was recorded by computerized dark adaptometry in 13 patients with chronic respiratory insufficiency treated by long-term oxygen therapy. At visits 1 and 3, the patients were administered their usual oxygen supplement. At visit 2, no oxygen was given. At each visit, an analysis of arterial blood gases measured pH, partial pressure of O(2) (Pao(2)), partial pressure of CO(2) (Paco(2)), base excess (BE), standard bicarbonate (HCO(3)), and arterial oxygen saturation. Pulse oximetry (POX) was also recorded.</p><p>RESULTS: Significant differences were recorded between visits 1 and 2 and between visits 2 and 3 for Pao(2), arterial oxygen saturation, and POX; no differences were found for pH, Paco(2), BE, or HCO(3). No differences were seen between visits 1 and 3 for any of the laboratory parameters. All patients had normal and unchanged dark adaptation at the three visits.</p><p>CONCLUSIONS: Hypoxia in chronic respiratory insufficiency was associated with normal dark adaptation, in contrast to hypoxia in healthy persons at high altitudes, which is known to produce impaired dark adaptation. The result may partly reflect the influence of Paco(2) on the lumen of choroidal and retinal vessels. At high altitudes, with hypocapnic vasoconstriction the oxygen supply to the retina is further compromised, resulting in reduced dark adaptation. The authors hypothesize that respiratory insufficiency with hypercapnia or normocapnia will have larger choroidal and retinal vessel lumens, added to by further dilation of retinal vessels during hypoxia. The tentative net effect would be preserved dark adaptation.</p>},
  author       = {Thylefors, Joakim and Piitulainen, Eeva and Havelius, Ulf},
  issn         = {1552-5783},
  language     = {eng},
  number       = {3},
  pages        = {12--1307},
  publisher    = {Association for Research in Vision and Ophthalmology Inc.},
  series       = {Investigative Ophthalmology & Visual Science},
  title        = {Dark adaptation during systemic hypoxia induced by chronic respiratory insufficiency},
  url          = {http://dx.doi.org/10.1167/iovs.08-2104},
  doi          = {10.1167/iovs.08-2104},
  volume       = {50},
  year         = {2009},
}