Our CE-marked COMET measurement system non-invasively measures oxygen availability [mmHg] in human skin cells with a high concentration of protoporphyrin IX.

We expect that measuring in the tissue cells, where oxygen is needed, rather than in the blood reflects the balance of supply and demand and will allow the assessment whether oxygen supply is sufficient and how effective interventions are. This should be relevant to the various treatments of the oxygen supply chain, from the lungs via hemoglobin and the heart through the vessels to the capillaries and the diffusion into the cells and mitochondria. It should also allow the detection of disturbances in the mitochondrial consumption of oxygen. Skin is an early warning sensor, so physicians should get time to act.  The measurement in the cells should prove useful for patient management, to direct therapy for resuscitation, to assess the effects of and necessity for interventions, to measure local tissue function, detect alterations of cellular metabolism and to help develop treatments for metabolic dysfunction.

Editors of Anesthesiology summarized a publication of research results with a prototype of the COMET and wrote that directly measuring tissue oxygenation “would be a major advance for perioperative medicine.” O’Brien and Schmidt wrote in a separate editorial for Anesthesiology (July 2016):A reliable measure of oxygen tension at the level of the mitochondria might significantly refine transfusion practice…  Indeed, any clinical scenario where cellular oxygenation might be compromised could potentially benefit… If mitochondrial PO2 can be measured reliably in humans, the potential value of this technique is hard to overestimate.

Several clinical trials are ongoing. Some of the results will be presented by R. Ubbink at ISICEM 2017 in Brussels, more publications will follow. We believe that research on the mitochondrial oxygen availability and consumption will soon lead to significant changes in clinical practice and new insights in several fields.

Further information is found in press releases of Erasmus Medical Center in Rotterdam,  Medgadget, Leiden University Medical Center and in the publications at the bottom of this page.

COMET measurement system

The new COMET measurement system determines oxygen availability as partial pressure of oxygen in mmHg. It measures in real time at the bedside and only in the active mitochondria of epidermal cells. It is available as a medical device in Europe for a first indication. It is not yet available outside Europe.

In a live demonstration at the 2015 meeting of the World Mitochondria Society in Berlin, Dr. Egbert Mik showed how a low dose of cyanide locally and reversibly blocked mitochondrial respiration in his skin. Romers et al. detected the limit of the critical hemoglobin concentration during isovolemic hemodilution in pigs, the skin provided early warning before kidney damage. Harms et al. showed coinciding changes in cellular respiration in rat skin, liver and buccal mucosa after induction of endotoxemia. Van Diemen et al. from the Center for Human Drug Research in Leiden measured increased oxygen utilization in skin cells of 28 human volunteers after 4 weeks of daily intake of statins. Dr. Mik’s group in Rotterdam observed the effects of vasoconstriction, vasodilation, fluid administration and red cell transfusion in patients.

The measurement in the cells should prove useful for patient management, to direct therapy for resuscitation, to assess the effects of and necessity for interventions, to detect alterations of cellular metabolism and to help develop treatments for metabolic dysfunction. Clinical trials are ongoing, more are planned.

Use the COMET measurement system as a low-burden adjunct to your studies and improve patient safety. Contact us for a quote (Europe only).

The science of cellular monitoring

Anesthesiologist Dr. Egbert Mik, building on his invention with Dr. Michiel Sinaasappel, developed a practical way to measure oxygen availability and consumption where oxygen is needed: in the tissue cells rather than in the blood. This first in-vivo measurement of mitochondrial oxygen availability is possible by determining the oxygen dependent duration of the afterglow of protoporphyrin IX,  a heme-precursor metabolized in epidermal mitochondria after local priming with aminolevulinic acid used in photodynamic therapy or diagnosis. The signal therefore originates only in active mitochondria and reflects the balance between oxygen supply and demand. The COMET’s standard skin sensor collects a signal from several square millimeters of epidermis, providing an average value for the different cells. A range of cellular oxygen availability is expected for different cells depending on their positions along capillaries and their distances from them (the Krogh model and its refinements  e.g., here or here, provide theoretical explanations). Intense perfusion can result in average epidermal mitoPO2 values only slightly below the arterial oxygen tension.  Temporary local pressure stops microvascular blood flow in the measurement region. Repeated measurements during and after pressure allow determination of cellular oxygen utilization and analysis of re-perfusion. Dr. Mik called his method the protoporphyrin IX-triplet state lifetime technique (PpIX-TSLT) and initiated the steps to make it clinically available. The technology and its application has been published in:

Eurostars supported the development and testing of the COMET measurement system (project E!7294). Photonics Healthcare collaborates with AMC, Erasmus Medical Center, Leiden University, Sanquin Blood Supply and Unitron.