Clinical neurophysiological assessment of sepsis-associated brain dysfunction: a systematic review

Abstract

Introduction: Several studies have reported the presence of electroencephalography (EEG) abnormalities or altered evoked potentials (EPs) during sepsis. However, the role of these tests in the diagnosis and prognostic assessment of sepsis-associated encephalopathy remains unclear.

Methods: We performed a systematic search for studies evaluating EEG and/or EPs in adult (≥ 18 years) patients with sepsis-associated encephalopathy. The following outcomes were extracted: a) incidence of EEG/EP abnormalities; b) diagnosis of sepsis-associated delirium or encephalopathy with EEG/EP; c) outcome.

Results: Among 1976 citations, 17 articles met the inclusion criteria. The incidence of EEG abnormalities during sepsis ranged from 12% to 100% for background abnormality and 6% to 12% for presence of triphasic waves. Two studies found that epileptiform discharges and electrographic seizures were more common in critically ill patients with than without sepsis. In one study, EEG background abnormalities were related to the presence and the severity of encephalopathy. Background slowing or suppression and the presence of triphasic waves were also associated with higher mortality. A few studies demonstrated that quantitative EEG analysis and EP could show significant differences in patients with sepsis compared to controls but their association with encephalopathy and outcome was not evaluated.

Conclusions: Abnormalities in EEG and EPs are present in the majority of septic patients. There is some evidence to support EEG use in the detection and prognostication of sepsis-associated encephalopathy, but further clinical investigation is needed to confirm this suggestion.

Figures

Figure 1

Preferred reporting items for systematic reviews and meta-analyses (PRISMA) flow diagram showing selection processes.

Figure 2

Typical electroencephalogaphic (EEG) findings in patients with sepsis-associated brain dysfunction. a) Frontal intermittent rhythmic delta activity (intermittent generalized rhythmic delta activity (GRDA), frontally predominant according to the ACNS Critical Care EEG terminology): burst of bilateral symmetrical and synchronous monomorphic delta (1.5 Hz in this case) activity predominating over the frontal regions. b) Triphasic waves (generalized periodic discharges (GPDs) with triphasic morphology according to the ACNS Critical Care EEG terminology): bilateral synchronous and symmetrical discharges occurring at a periodic interval (1.5 Hz); each discharge has three phases (negative–positive–negative), the second phase has the highest amplitude and each phase is longer in duration than the previous one. c) Nonconvulsive status epilepticus: presence of generalized periodic discharges at 2 to 2.5 Hz maximal over the frontal regions; discharges have a sharp wave morphology; independent sporadic sharp waves are present over the left posterior region. d) Moderate generalized slowing (same patient as in c after administration of IV levetiracetam): disappearance of generalized periodic discharges; mixed theta-delta background. ACNS, American Clinical Neurophysiology Society.