S100B as a predictor of delirium in critically ill obstetric patients: A nested case–control study

Background: Delirium is a neuropsychiatric illness that lasts for a short period of time. The incidence of delirium in the intensive care unit (ICU) varies from 20% to 80%. Methods: A nested case–control study was carried out in the obstetric ICU. Individuals were divided into three groups: critically ill obstetric women who had delirium on admission (Group A), women who developed delirium within follow-up of 7 days (Group B), and women who did not develop delirium after follow-up of 7 days (Group C). The APACHE II score was used to assess critical illness severity. The Richmond Agitation-Sedation Scale was used to assess the alertness or sedation level of patients, and the Confusion Assessment Method (ICU scale) was used to assess the presence of delirium. S100B was measured by human S100B calcium-binding protein B ELISA kit (Elabscience Biotechnology, Houston, USA). Results: Severe preeclampsia and antepartum eclampsia were significantly associated with delirium. S100B levels in Group B were found to be significantly higher than those in Group C. S100B levels were higher in patients with >2 morbidities in comparison to patients with two morbidities. At a cutoff value of >169.25 pg/ml, S100B had a sensitivity of 74% and a specificity of 87.2% to discriminate cases of delirium from nondelirium. Conclusion: The rise in S100B levels was approximately three times greater in those who developed delirium as compared to those who did not. It is a more specific predictor of delirium.