Monitoring of CBFV and time characteristics of oxygen-induced acute CNS toxicity in humans.
BACKGROUND
Hyperbaric oxygen can cause central nervous system (CNS) toxicity with seizures. We tested the hypothesis that CNS toxicity could be predictable by cerebral blood flow velocity (CBFV) monitoring.


METHODS
We monitored 369 mandatory oxygen tolerance tests (30 min, 280 kPa O(2)) by video-documentation and since May 2005 by additional CBFV registration (n = 61).


RESULTS
The onset of early manifestations of CNS toxicity was documented in 11 of 369 tests within 22 +/- 3 min. These included twitches and/or agitation, 6 of 11 and tonic-clonic seizures in 5 of 11 cases. In both cases with CBFV monitoring, an increase in CBFV preceded symptom onset, once followed by seizure, once without seizure after timely oxygen reduction.


CONCLUSIONS
During exposure to 280 kPa oxygen at rest a constant delay of approximately 20 min precedes the onset of central nervous oxygen toxicity. An increase in CBFV may indicate the impending seizure.
Koch
A E
AE
German Naval Medical Institute, Kiel-Kronshagen, Germany. koch@email.uni-kiel.de
Kähler
W
W
Wegner-Bröse
H
H
Weyer
D
D
Kuhtz-Buschbeck
J
J
Deuschl
G
G
Eschenfelder
C C
CC
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000187:drug effects*; D002493:Central Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004562:Electrocardiography; D006801:Humans; D006931:Hyperbaric Oxygenation; D018496:Hyperoxia / Q000503:physiopathology*; D012640:Seizures / Q000175:diagnosis / Q000209:etiology