Intracranial pressure and cerebral perfusion pressure in patients developing brain death.
We investigated whether a critical rise of intracranial pressure (ICP) leading to a loss of cerebral perfusion pressure (CPP) could serve as a surrogate marker of brain death (BD).



We retrospectively analyzed ICP and CPP of patients in whom BD was diagnosed (n = 32, 16-79 years). Intracranial pressure and CPP were recorded using parenchymal (n = 27) and ventricular probes (n = 5). Data were analyzed from admission until BD was diagnosed.



Intracranial pressure was severely elevated (mean ± SD, 95.5 ± 9.8 mm Hg) in all patients when BD was diagnosed. In 28 patients, CPP was negative at the time of diagnosis (-8.2 ± 6.5 mm Hg). In 4 patients (12.5%), CPP was reduced but not negative. In these patients, minimal CPP was 4 to 18 mm Hg. In 1 patient, loss of CPP occurred 4 hours before apnea completed the BD syndrome.



Brain death was universally preceded by a severe reduction of CPP, supporting loss of cerebral perfusion as a critical step in BD development. Our data show that a negative CPP is neither sufficient nor a prerequisite to diagnose BD. In BD cases with positive CPP, we speculate that arterial blood pressure dropped below a critical closing pressure, thereby causing cessation of cerebral blood flow.
Department of Neurology, Charité-Universitätsmedizin, 13353 Berlin, Germany. Electronic address: farid.salih@charite.de.
Farid
F
Salih
Department of Neurology, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Martin
M
Holtkamp
Department of Neurology, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Stephan A
SA
Brandt
Department of Neurology, St Josefs-Krankenhaus, 14471 Potsdam, Germany.
Olaf
O
Hoffmann
Department of Neurology, Bundeswehr-Krankenhaus, 10115 Berlin, Germany.
Florian
F
Masuhr
Department of Neurology, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Stephan
S
Schreiber
Department of Neurology, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Florian
F
Weissinger
Department of Neurosurgery, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Peter
P
Vajkoczy
Department of Neurosurgery, Charité-Universitätsmedizin, 13353 Berlin, Germany.
Stefan
S
Wolf
D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D001926:Brain Death / Q000503:physiopathology*; D001930:Brain Injuries / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003422:Critical Care; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055815:Young Adult
D015415:Biomarkers
Brain death; Cerebral perfusion pressure; Critical closing pressure; Intracranial pressure