Changes in auditory evoked potentials induced by postsurgical sepsis

Abstract

Background: Clinical examination may be less sensitive than electrophysiological methods in the diagnosis of sepsis-associated encephalopathy. The aim of this study was to evaluate the changes in A-line Autoregression Index (AAI) induced by postsurgical sepsis.

Methods: The study involved patients admitted to the University High Dependency Unit (HDU) after major abdominal surgery. Patients that later developed sepsis entered the septic group (SG), and the other patients formed the control group (CG). The SG underwent measurements of AAI and tests for bedside mental status, consciousness abnormalities, heart rate, blood pressure, respiratory rate, tympanic temperature and white blood cell concentration at HDU admission (T1) and within 6 hours after the diagnosis of sepsis was confirmed (T2). The CG was evaluated at T1 and at day 4 of the HDU stay. All measured variables were compared between CG and SG at T1 and T2 using the Mann Whitney test with a significance cut-off of P<0.001.

Results: The CG and SG included 30 and 24 patients, respectively. There was no difference between the CG and SG at T1. At T2, the median AAI was significantly higher in the CG than in the SG. Significant differences were found also for reactive protein C and body temperature.

Conclusion: The occurrence of sepsis significantly reduces AAI. Measurement of AAI thus has the potential to be a reliable diagnostic test to identify subclinical sepsis-associated encephalopathy.