title: A monitor for Cellular Oxygen METabolism (COMET): monitoring tissue oxygenation at the mitochondrial level.
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.
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Rinse
authors.identifier: http://orcid.org/0000-0003-0005-0502
authors.initials: R
authors.lastname: Ubbink
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Mark A Wefers
authors.initials: MAW
authors.lastname: Bettink
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Rineke
authors.initials: R
authors.lastname: Janse
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Floor A
authors.initials: FA
authors.lastname: Harms
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Tanja
authors.initials: T
authors.lastname: Johannes
authors.affiliation: Photonics Healthcare B.V., Utrecht, The Netherlands.
authors.forename: F Michael
authors.initials: FM
authors.lastname: Münker
authors.affiliation: Department of Anesthesiology, Laboratory for Experimental Anesthesiology, Erasmus MC - University Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands. e.mik@erasmusmc.nl.|Department of Intensive Care, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands. e.mik@erasmusmc.nl.
authors.forename: Egbert G
authors.initials: EG
authors.lastname: Mik
mesh_terms: D000622:Aminolevulinic Acid / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D004867:Equipment Design; D006801:Humans; D007834:Lasers; D008833:Microcirculation; D008928:Mitochondria / Q000378:metabolism*; D018670:Monitoring, Ambulatory / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011524:Protoporphyrins / Q000737:chemistry*; D012815:Signal Processing, Computer-Assisted; D012867:Skin / Q000378:metabolism / Q000473:pathology*
chemical_list: D001672:Biocompatible Materials; D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX; D010100:Oxygen
keywords: COMET; Diagnostics; Mitochondrial oxygen tension (mitoPO2); PpIX-TSLT; Tissue oxygenation