Mark Wefers Bettink

Chapter 7 130 the MEC allowed for a deferred consent procedure. Deferred consent or deferred proxy consent had to be obtained within a maximum of 72 hours, and before preparation of the second measurement was started. If the patient or legal representatives objected, the subject was excluded from the study and data obtained from the first measurement was not used for further analysis and deleted. During the deferred consent process, some patients would be prepared for a first measurement, before informed (proxy) refusal was given. The procedures were in accordance with the Declaration of Helsinki, including current revisions, and Good Clinical Practice guidelines. Time of admission allowed the first measurement to be taken in less than 24 hours after admission to the ICU. Admission to another centers’ ICU, the post anesthesia care unit (PACU) or coronary care unit (CCU) prior to the current ICU-admission were considered as ICU time as well. Exclusion criteria were: diagnosis of mental disability, diagnosis of mitochondrial disease, pregnancy or porphyria. This study was a single-center prospective observational study in which we measured mitochondrial function parameters oxygen tension (mitoPO 2 ) and oxygen consumption (mitoVO 2 ) within 24 hours of admission to the ICU. Blood samples were taken directly after the oxygen consumption measurement with the COMET monitor. If patients were available a second measurement was performed 5-7 days after ICU admittance. Patients with A) a positive qSOFA (quick Sepsis Related Organ Failure Assessment) score ( ≥ 2 criteria) and suspected infection; or B) a recent sepsis diagnosis by an intensivist or referring specialist, were included in the sepsis group. If patients did not have a positive qSOFA or a diagnosis of sepsis they were included in the control group. A standardized form was filled in at admission for each included patient with data from the medical record. Study procedures Measurement of mitoPO2 and mitoVO2 using the COMET monitor Oxygen-dependent quenching of the delayed fluorescence lifetime of mitochondrial PpIX is the first known method to measure mitoPO 2 in living cells and tissues, in a non- invasive and feasible manner in humans. PpIX is the final precursor of heme in the heme