Retinal oximetry with a prototype handheld oximeter during hyperoxia

Acta Ophthalmologica, vol. 99, pp. e1390–e1395

Abstract

PURPOSE: Retinal oximetry measures oxygen saturation in retinal vessels. With the introduction of a mobile handheld prototype oximeter, this technique will become available for a broader patient population including bedridden patients and newborn babies. The objective is to determine the sensitivity of this handheld oximeter in room air and during isocapnic hyperoxia. A comparison is made between the handheld oximeter and the Oxymap T1. METHODS: Thirteen young healthy subjects with a mean age of 25 ± 2 years were recruited at the Leiden University Medical Center. Retinal oximetry images were acquired during normoxia and during isocapnic hyperoxia for both the prototype oximeter and the OxymapT1. Isocapnic hyperoxia was induced with the dynamic end-tidal forcing technique. For both oximeters, the oxygen saturation and vessel width were measured with Oxymap Analyzer software. The hyperoxic state was verified with blood gas analysis. RESULTS: The mean oxygen saturation measured with the handheld oximeter in arterioles was 91.3% ± 3.9% during normoxia and 94.6% ± 3.9% during hyperoxia (p = 0.001). Oxygen saturation in venules was 56.3% ± 9.8% during normoxia and 82.2 ± 7.4% during hyperoxia (p < 0.001). For the Oxymap T1, the mean oxygen saturation for arterioles was 94.0% ± 2.6% during normoxia and 95.4%±3.2% during hyperoxia (p = 0.004). For the venules, the oxygen saturation was during normoxia 58.9%±3.2% and 84.3 ± 4.0% during hyperoxia (p < 0.001). CONCLUSION: The handheld retinal oximeter is sensitive to the changes in inhaled oxygen concentration. A small increase in oxygen saturation was measured in the arterioles and a larger increase in the venules. The handheld oximeter gives similar values as the 'gold standard' Oxymap T1 oximeter.

Authors 7

1. Wouter B.H.J. Vehmeijer Aachen Department of Ophthalmology Leiden University Medical Center Leiden the Netherlands Department of Ophthalmology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Ophthalmology Leiden University Medical Center Leiden The Netherlands

   Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands

2. Kelly Jonkman Aachen Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands Department of Anesthesiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands

   Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands

3. Sveinn Hákon Hardarson

   University of Iceland

   Affiliation as printed

   Department of Physiology University of Iceland Reykjavik Iceland

   Department of Physiology, University of Iceland, Reykjavik, Iceland

4. Leon P.H.J. Aarts Aachen Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands Department of Anesthesiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands

   Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands

5. Einar Stefánsson

   University of Iceland · National University Hospital of Iceland

   Affiliation as printed

   Department of Ophthalmology University of Iceland Landspítali, Reykjavik Iceland

   Department of Physiology University of Iceland Reykjavik Iceland

   Department of Physiology, University of Iceland, Reykjavik, Iceland

6. Albert Dahan Aachen Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands Department of Anesthesiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Anesthesiology Leiden University Medical Center Leiden The Netherlands

   Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands

7. Nicoline Elisabeth Schalij-Delfos corresponding Aachen Department of Ophthalmology Leiden University Medical Center Leiden the Netherlands Department of Ophthalmology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Ophthalmology Leiden University Medical Center Leiden The Netherlands

   Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands