Cortisol levels and neuropsychiatric diagnosis as markers of postoperative delirium: a prospective cohort study
1 Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Czechoslowacka 8/10, 92-216 Lodz, Poland
2 Department of Anaesthesiology and Intensive Cardiologic Care, 1st Chair of Cardiology and Cardiac Surgery, Medical University of Lodz, Sterlinga 1/3, 91-425 Lodz, Poland
3 Central Veterans Hospital, Sterlinga 1/3, 91-425 Lodz, Poland
4 The Centre for Psychiatry at The Wolfson Institute for Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 3rd floor Dominion House, 59 Bartholomew Close, London EC1A 7E, UK
5 Department of Cardiac Surgery, 1st Chair of Cardiology and Cardiac Surgery, Medical University of Lodz, Sterlinga 1/3, 91-425 Lodz, Poland
Critical Care 2013, 17:R38 doi:10.1186/cc12548Published: 1 March 2013
The pathophysiology of delirium after cardiac surgery is largely unknown. The purpose of this study was to investigate whether increased concentration of preoperative and postoperative plasma cortisol predicts the development of delirium after coronary artery bypass graft surgery. A second aim was to assess whether the association between cortisol and delirium is stress related or mediated by other pathologies, such as major depressive disorder (MDD) or cognitive impairment.
The patients were examined 1 day preoperatively with the Mini International Neuropsychiatric Interview and the Montreal Cognitive Assessment and the Trail Making Test to screen for depression and for cognitive impairment, respectively. Blood samples for cortisol levels were collected both preoperatively and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used within the first 5 days postoperatively to screen for a diagnosis of delirium.
Postoperative delirium developed in 36% (41 of 113) of participants. Multivariate logistic regression analysis revealed two groups independently associated with an increased risk of developing delirium: those with preoperatively raised cortisol levels; and those with a preoperative diagnosis of MDD associated with raised levels of cortisol postoperatively. According to receiver operating characteristic analysis, the most optimal cutoff values of the preoperative and postoperative cortisol concentration that predict the development of delirium were 353.55 nmol/l and 994.10 nmol/l, respectively.
Raised perioperative plasma cortisol concentrations are associated with delirium after coronary artery bypass graft surgery. This may be an important pathophysiological consideration in the increased risk of postoperative delirium seen in patients with a preoperative diagnosis of MDD.