Clinical Observational Study into Mitochondrial Oxygenation Predicting Ominous Lactate In Trajectory around Abdominal Surgery

Lactate is produced during anaerobic metabolism and is commonly used as a marker for inadequate tissue perfusion. As studies show that even a small rise in lactate levels is associated with increased morbidity and mortality, therapy strategies have been based on increasing lactate clearance and reducing lactate levels. Since lactate changes take place over hours, a more sensitive monitoring parameter has been long sought after. Previous studies have shown the potential of the recently introduced Cellular Oxygen METabolism (COMET) monitor (Photonics Healthcare, Utrecht), which measures cutaneous mitochondrial oxygen tension (mitoPO2) and oxygen consumption (mitoVO2).This study will provide the base for future studies which investigate whether mitochondrial oxygen monitoring can predict changes in serum lactate and if it can be used as a tool for optimizing hemodynamic management.

Cutaneous mitochondrial oxygen tension measurements are correlated with serum lactate measurements.

- On admission to the clinical ward the day before surgery the researcher will visit the patient and two ALA-plasters will be placed on the upper arm/shoulder.
- Health status will be checked according to the pre-operative form, medication use and medical history.
- The measurements will be started before induction. The mitoPO2 shall be measured in intervals and measurements will continue up until 48 hours post-operatively or until available. Lactate measurements will be performed four times per 24 hours, adhering to standard care protocol as much as possible.
- Capillary refill and delta temperature will be derived from the medical dossier when performed by hospital personnel. Alternatively, delegated study personnel will measure core and skin temperature and test capillary refill four times per 24 hours.
- After 48 hours the probe will be removed and the skin exposed to ALA will be covered with a light-shielding plaster for 24 hours.
- The local site of the plasters will be checked 24 hours after the plaster in question has been removed.
- Clinical outcome and complications will be checked after one month in the electronic patient dossier
- Patients will be called two weeks after discharge by the researcher to gain feedback about their experiences during the study period. This will include feedback on the measurements, adherence of the COMET Sensor Holder to their arm for 48 hours post-operatively and if they have experienced any adverse events after their discharge out of the hospital.