Postoperative delirium: the findings from a multidisciplinary survey

Association Between Risk of Stroke and Delirium After Cardiac Surgery and a New Electroencephalogram Index of Interhemispheric Similarity

OBJECTIVES

Neurologic complications after surgery (stroke, delirium) remain a major concern despite advancements in surgical and anesthetic techniques. The authors aimed to evaluate whether a novel index of interhemispheric similarity, the lateral interconnection ratio (LIR), between 2 prefrontal electroencephalogram (EEG) channels could be associated with stroke and delirium following cardiac surgery.

DESIGN

Retrospective observational study.

SETTING

Single university hospital.

PARTICIPANTS

A total of 803 adult patients without documentation of a previous stroke, who underwent cardiac surgery with cardiopulmonary bypass (CPB) between July 2016 and January 2018.

INTERVENTIONS

The LIR index was calculated retrospectively from the patients' EEG database.

MEASUREMENTS AND MAIN RESULTS

LIR was analyzed intraoperatively every 10 seconds and compared among patients with postoperative stroke, patients with delirium, and patients without documented neurologic complications, during 5 key periods, each lasting10 minutes: (1) surgery start, (2) before CPB, (3) on CPB, (4) after CPB, and (5) surgery end. After cardiac surgery, 31 patients suffered from stroke; 48 patients were diagnosed with delirium; and 724 had no documented neurologic complications. Patients with stroke demonstrated a decrease in LIR index between the start of surgery and the postbypass period of 0.08 (0.01, 0.36 [21]; median and [interquartile range {IQR}]; valid EEG samples); whereas there was no similar decrease in the no-dysfunction group (-0.04 [-0.13, 0.04; {551}], p < 0.0001). Patients with delirium showed a decrease in LIR index between the start of surgery and the end of the surgery by 0.15 (0.02, 0.30 [12]), compared with no such decrease in the no-dysfunction group (-0.02 [-0.12, 0.08 {376}], p ≈ 0.001).

CONCLUSIONS

After improvement of SNR, it might be of value to further study the index decrease as an indication for risk for brain injury after surgery. The timing of decrease (after CPB or end of surgery) may provide hints regarding the injury pathophysiology and its onset.

Periinterventional inflammation and blood transfusions predict postprocedural delirium after percutaneous repair of mitral and tricuspid valves

Objectives

The aim of this study was to examine predictors and impact of postoperative delirium (POD) on outcome after percutaneous repair of mitral and tricuspid valves.

Background

POD is common in elderly patients and contributes to increased health care costs and worse outcome. Predictors of POD in percutaneous mitral or tricuspid valve procedures are unclear.

Methods

In a prospective single-center study, patients were screened for POD using the Confusion Assessment Method on the first and second postprocedural days, and up until 7 days in patients with clinical suspicion of delirium. Associations of POD with baseline characteristics, periprocedural outcome and mid-term mortality were examined.

Results

One hundred and seventy-seven patients were included (median age 78 years [72–82], 41.8% female) and median (IQR) follow-up was 489 (293–704) days. Patients developing POD (n = 16, 9%) did not differ in baseline and procedural characteristics but more often received postinterventional blood transfusions (37.5% vs. 9.9%, p value = 0.007) and suffered from infections (43.8% vs. 9.9%, p value = 0.001). Patients with POD showed worse survival (HR: 2.71 [1.27–5.78]; p = 0.01), with an estimated 1-year survival of 46 ± 13% compared to 80 ± 3% in patients without POD (log-rank p value 0.007). In multivariate Cox regression, POD remained a significant predictor of mid-term mortality (HR 4.75 [1.97–11.5]; p = 0.001).

Conclusion

After percutaneous mitral or tricuspid valve repair, POD was independently associated with worse mid-term survival. Procedure- rather than patient-associated characteristics such as blood transfusions and infections emerged as important risk factors for development of POD. Considering the substantial prognostic impact of POD, further studies on its prevention are warranted to improve patient outcome.