Reliability in the assessment of paediatric somatosensory evoked potentials post cardiac arrest

Objective: To measure inter- and intra-rater agreement in the interpretation of cortical somatosensory evoked potential (SSEP) components following paediatric cardiac arrest (CA) in multi-professional neurophysiology teams. Methods: Thirteen professionals blinded to patient outcome interpreted 96 SSEPs in paediatric patients 24-/48-/72-hours following CA. Of these, 34 were duplicates used to assess intra-rater agreement. Consistent interpretations (absent/present/indeterminate) between scientists (who record/identify SSEP components) and neurophysiologists (who provide prognostic SSEP interpretation) were expressed as percentages. Rates of agreement were calculated using Fleiss’ kappa coefficient (K). Results: Unanimous agreement between professionals was present in 40% (95%CI: 28–54%) of the interpreted SSEPs, with a K value of 0.62 (95%CI: 0.55–0.70) based on average agreement. Agreement was similar between neurophysiologists (K = 0.67; 95%CI: 0.57–0.77) and scientists (K = 0.62; 95%CI: 0.54–0.70) but lower in patients < 2 years old (K = 0.23; 95%CI: 0.14–0.33) and in those with poor outcome (K = 0.21; 95%CI: 0.07–0.35). No SSEP was unanimously interpreted as absent and 92% (95%CI: 89–95%) of duplicate SSEPs were interpreted consistently. Conclusion: Despite substantial agreement when interpreting prognostic SSEPs, this was significantly lower in children with poor outcome and of younger age. Significance: Clinicians using SSEPs in the intensive care unit should be aware of the inter-rater variability when interpreting SSEPs as absent.