Interrater variability of EEG interpretation in comatose cardiac arrest patients.
OBJECTIVE
EEG is widely used to predict outcome in comatose cardiac arrest patients, but its value has been limited by lack of a uniform classification. We used the EEG terminology proposed by the American Clinical Neurophysiology Society (ACNS) to assess interrater variability in a cohort of cardiac arrest patients included in the Target Temperature Management trial. The main objective was to evaluate if malignant EEG-patterns could reliably be identified.


METHODS
Full-length EEGs from 103 comatose cardiac arrest patients were interpreted by four EEG-specialists with different nationalities who were blinded for patient outcome. Percent agreement and kappa (κ) for the categories in the ACNS EEG terminology and for prespecified malignant EEG-patterns were calculated.


RESULTS
There was substantial interrater agreement (κ 0.71) for highly malignant patterns and moderate agreement (κ 0.42) for malignant patterns. Substantial agreement was found for malignant periodic or rhythmic patterns (κ 0.72) while agreement for identifying an unreactive EEG was fair (κ 0.26).


CONCLUSIONS
The ACNS EEG terminology can be used to identify highly malignant EEG-patterns in post cardiac arrest patients in an international context with high reliability.


CONCLUSIONS
The establishment of strict criteria with high transferability between interpreters will increase the usefulness of routine EEG to assess neurological prognosis after cardiac arrest.
Department of Clinical Sciences, Division of Clinical Neurophysiology, Lund University, Lund, Sweden. Electronic address: erik.westhall@med.lu.se.
Erik
E
Westhall
Department of Clinical Sciences, Division of Clinical Neurophysiology, Lund University, Lund, Sweden. Electronic address: ingmar.rosen@skane.se.
Ingmar
I
Rosén
Department of Neurology, CHUV and University of Lausanne, Lausanne, Switzerland. Electronic address: andrea.rossetti@chuv.ch.
Andrea O
AO
Rossetti
Department of Neurology/Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: a.f.vanrootselaar@amc.uva.nl.
Anne-Fleur
AF
van Rootselaar
Department of Clinical Neurophysiology, Rigshospitalet University Hospital, Copenhagen, Denmark. Electronic address: neurology@dadlnet.dk.
Troels
T
Wesenberg Kjaer
Department of Clinical Sciences, Division of Intensive and Perioperative Care, Lund University, Lund, Sweden. Electronic address: hans.friberg@skane.se.
Hans
H
Friberg
Department of Intensive Care Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: j.horn@amc.uva.nl.
Janneke
J
Horn
Department of Anaesthesia and Intensive Care, Intensive Care Unit, Helsingborg Hospital, Helsingborg, Sweden. Electronic address: niklas.nielsen@med.lu.se.
Niklas
N
Nielsen
R&D Centre Skane, Skane University Hospital, Lund, Sweden. Electronic address: susann.ullen@skane.se.
Susann
S
Ullén
Department of Clinical Sciences, Division of Neurology, Lund University, Lund, Sweden. Electronic address: tobias.cronberg@skane.se.
Tobias
T
Cronberg
D000368:Aged; D003128:Coma / Q000175:diagnosis* / Q000503:physiopathology*; D004569:Electroencephalography / Q000592:standards*; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation
Brain injury; Cardiac arrest; EEG; Hypothermia; Interrater variability; Prognosis