Recent Advances in Preventing and Managing Postoperative Delirium [version 1; peer review: 2 approved]

Postoperative delirium is a common and harrowing complication in older surgical patients. Those with cognitive impairment or dementia are at especially high risk for developing postoperative delirium; ominously, it is hypothesized that delirium can accelerate cognitive decline and the onset of dementia, or worsen the severity of dementia. Awareness of delirium has grown in recent years as various medical societies have launched initiatives to prevent postoperative delirium and alleviate its impact. Unfortunately, delirium pathophysiology is not well understood and this likely contributes to the current state of low-quality evidence that informs perioperative guidelines. Along these lines, recent prevention trials involving ketamine and dexmedetomidine have demonstrated inconsistent findings. Non-pharmacologic multicomponent initiatives, such as the Hospital Elder Life Program, have consistently reduced delirium incidence and burden across various hospital settings. However, a substantial portion of delirium occurrences are still not prevented, and effective prevention and management strategies are needed to complement such multicomponent non-pharmacologic therapies. In this narrative review, we examine the current understanding of delirium neurobiology and summarize the present state of prevention and management efforts

Association between delirium and cognitive change after cardiac surgery

Background: Previous studies provide inconsistent data on whether postoperative delirium (POD) is a risk factor for postoperative cognitive decline (POCD). We thus investigated the relationship between POD and cognitive change after cardiac surgery and assessed the relationship between preoperative cognitive domain scores and POD. Methods: Postoperative delirium was assessed with the Confusion Assessment Method (CAM) adapted for the intensive care unit and the conventional CAM accompanied by chart review. Cognitive function was assessed with a neuropsychological test battery before elective cardiac surgery and 1 month and 1 yr afterwards. Cognitive change was calculated using the Reliable Change Index (RCI). Multiple linear regression was used to adjust for confounding. Results: Of the 184 patients who completed baseline assessment, 23 (12.5%) developed POD. At 1 month, the decline in cognitive performance was worse in patients with POD [median composite RCI -1.00, interquartile range (IQR) -1.67 to 0.28] than in patients without POD (RCI -0.04, IQR -0.70 to 0.63, P =0.02). At 1 yr, both groups showed cognitive improvement on average compared with baseline (POD patients median composite RCI 0.25, IQR -0.42 to 1.31, vs non-POD patients RCI 0.92, IQR 0.18-1.53; P =0.08). Correction for differences in age and level of education did not change the results. Patients with POD performed less well than patients without POD on the preoperative Trailmaking test part A ( P =0.03). Conclusions: Postoperative delirium is independently associated with cognitive decline 1 month after surgery, but cognitive performance generally recovers in 1 yr. Patients with a predisposition to POD can be identified before surgery by worse performance in an attention task. Clinical trial registration: NCT00293592

Effects of dexamethasone on cognitive decline after cardiac surgery a randomized clinical trial

Background: Cardiac surgery can be complicated by postoperative cognitive decline (POCD), which is characterized by impaired memory function and intellectual ability. The systemic inflammatory response that is induced by major surgery and cardiopulmonary bypass may play an important role in the etiology of POCD. Prophylactic corticosteroids to attenuate the inflammatory response may therefore reduce the risk of POCD. The authors investigated the effect of intraoperative high-dose dexamethasone on the incidence of POCD at 1 month and 12 months after cardiac surgery. Methods: This multicenter, randomized, double-blind, placebo-controlled trial is a preplanned substudy of the DExamethasone for Cardiac Surgery trial. A total of 291 adult patients undergoing cardiac surgery with cardiopulmonary bypass were recruited in three hospitals and randomized to receive dexamethasone 1 mg/kg (n = 145) or placebo (n = 146). The main outcome measures were incidence of POCD at 1- And 12-month follow-up, defined as a decline in neuropsychological test performance beyond natural variability, as measured in a control group. Results: At 1-month follow-up, 19 of 140 patients in the dexamethasone group (13.6%) and 10 of 138 patients in the placebo group (7.2%) fulfilled the diagnostic criteria for POCD (relative risk, 1.87; 95% CI, 0.90 to 3.88; P = 0.09). At 12-month follow-up, 8 of 115 patients in the dexamethasone group (7.0%) and 4 of 114 patients (3.5%) in the placebo group had POCD (relative risk, 1.98; 95% CI, 0.61 to 6.40; P = 0.24). Conclusion: Intraoperative high-dose dexamethasone did not reduce the risk of POCD after cardiac surgery