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. 2017 Dec;31(6):1143-1150.
doi: 10.1007/s10877-016-9966-x. Epub 2016 Dec 20.

A monitor for Cellular Oxygen METabolism (COMET): monitoring tissue oxygenation at the mitochondrial level

Rinse Ubbink  1 , Mark A Wefers Bettink  1 , Rineke Janse  1 , Floor A Harms  1 , Tanja Johannes  1 , F Michael Münker  2 , Egbert G Mik  3   4
Affiliations

A monitor for Cellular Oxygen METabolism (COMET): monitoring tissue oxygenation at the mitochondrial level

Rinse Ubbink et al. J Clin Monit Comput. 2017 Dec.

Abstract

After introduction of the protoporphyrin IX-triplet state lifetime technique as a new method to measure mitochondrial oxygen tension in vivo, the development of a clinical monitor was started. This monitor is the "COMET", an acronym for Cellular Oxygen METabolism. The COMET is a non-invasive electrically powered optical device that allows measurements on the skin. The COMET is easy to transport, due to its lightweight and compact size. After 5-aminolevulinic acid application on the human skin, a biocompatible sensor enables detection of PpIX in the mitochondria. PpIX acts as a mitochondrially located oxygen-sensitive dye. Three measurement types are available in the touchscreen-integrated user interface, 'Single', 'Interval' and 'Dynamic measurement'. COMET is currently used in several clinical studies in our institution. In this first description of the COMET device we show an incidental finding during neurosurgery. To treat persisting intraoperative hypertension a patient was administered clonidine, but due to rapid administration an initial phase of peripheral vasoconstriction occurred. Microvascular flow and velocity parameters measured with laser-doppler (O2C, LEA Medizintechnik) decreased by 44 and 16% respectively, but not the venous-capillary oxygen saturation. However, mitochondrial oxygen tension in the skin detected by COMET decreased from a steady state of 48 to 16 mmHg along with the decrease in flow and velocity. We conclude that COMET is ready for clinical application and we see the future for this bedside monitor on the intensive care, operating theater, and testing of mitochondrial effect of pharmaceuticals.

Keywords: COMET; Diagnostics; Mitochondrial oxygen tension (mitoPO2); PpIX-TSLT; Tissue oxygenation.

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Conflict of interest statement

Dr. E.G. Mik and F. Michael Münker are founders and shareholders of Photonics Healthcare, a company aimed at making the delayed fluorescence lifetime technology available to a broad public. Photonics Healthcare B.V. holds the exclusive licenses to several patents regarding this technology, filed and owned by the Academic Medical Center in Amsterdam and the Erasmus Medical Center in Rotterdam, The Netherlands.

Figures

Fig. 1
Fig. 1
COMET monitor and skin sensor
Fig. 2
Fig. 2
COMET skin sensor position on the sternum
Fig. 3
Fig. 3
Detailed view of skin sensor
Fig. 4
Fig. 4
A typical dynamic measurement of mitochondrial partial oxygen pressure (mitoPO2) by COMET measurement system. A sample of 120 s is shown. In the first 20 s the baseline was determined, afterwards light pressure was applied on the sensor to stop microcirculation and the oxygen disappearance rate (ODR) was measured. At 60 s pressure was released
Fig. 5
Fig. 5
a Flow in arbitrary flow units (FU) and arbitrary velocity in velocity units (VU) of microcirculation as measured with probe 2 (P2S) O2C. b Capillary venous saturation (SO2)** as measured by O2C and mitochondrial partial oxygen pressure (mitoPO2) as measured by the COMET
See this image and copyright information in PMC

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