The aim of the study is to verify the reliability of the current purely clinical examination of the pupils (without the support of a pupillometer) in the context of clinically suspected brain death, compared to the results of a non-invasive, automated, and highly precise monocular pupillometric examination.

This prospective quality control study will evaluate the reliability of the clinical exam regarding pupils' reaction to light (as performed by two board certified physicians in Neurology and/or Intensive Care Medicine) as recommended by the SAMW guidelines for brain death diagnosis (SAMW-guidelines) when compared to the results of a noninvasive automated and highly-precise pupillometry in adult patients with clinically suspected brain death. Automated pupillometric measurements will be performed by the PI (RS), or the co-investigator (Dr. Pascale Grzonka) using the NeurOptics® NPi®-200 pupillometer system immediately before and after the standardized diagnostic workup for suspected brain death. In addition, demographics, clinical characteristics , treatment and laboratory data from the patients examined will be anonymously collected.

Inclusion Criteria:

• Suspected diagnosis of brain death
• Brain death diagnostic procedures planned
• Treated at the intensive care unit at the University Hospital Basel (USB)

The patient population is defined as all adult patients (i.e. ≥18 years of age) treated on the intensive care unit at the University Hospital Basel (USB) in whom the treating physicians suspect brain death and plan to perform brain death diagnostic procedures.