Predictors of postoperative cognitive dysfunction in adult patients undergoing elective cardiac surgery

Comparative evaluation of intraoperative dexmedetomidine versus lidocaine for reducing postoperative cognitive decline in the elderly: a prospective randomized controlled trial

INTRODUCTION

Neuroinflammation, neuronal cytotoxicity, and apoptosis due to exposure to anaesthetic agents are often implicated in postoperative cognitive dysfunction (POCD). Lidocaine and dexmedetomidine have been shown to suppress the neuron-specific markers of inflammation, and we aimed to compare their neuroprotective efficacy in elderly patients.

MATERIAL AND METHODS

This prospective randomized control study compared the incidence of POCD in ASA I/II patients aged 60 to 80 years without any history of substance abuse or any disorder affecting cognition. Dexmedetomidine and lidocaine were administered intraoperatively, and their effects on POCD were correlated with serum levels of IL-1, IL-6, TNF-a, amyloid-β, and S100 on postoperative day 3. POCD was assessed by the Stroop test, Trail making test-B, Porteus Maze test, Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA) on the day before surgery and the third postoperative day, along with blood samples.

RESULTS

Demographic parameters, anaesthesia duration, exposure to anaesthetic gases, intraoperative opioid use, and blood transfusion were similar in the lidocaine ( n = 31) and dexmedetomidine ( n = 29) groups. The incidence of POCD was 29.03% in the lidocaine group and 24.1% in the dexmedetomidine group ( P = 0.77). On postoperative day 3, IL-1 levels increased by 449% with lidocaine and 202% with dexmedetomidine ( P = 0.03). TNF-a, IL-6, and S-100β levels increased similarly in both groups. There was no significant correlation between percentage changes in neuropsychological tests and biomarkers.

CONCLUSIONS

There was no significant difference in the incidence of POCD, but dexmedetomidine had a better anti-inflammatory effect in terms of lesser rise of postoperative IL-1 compared to lidocaine.

Predictors of cognitive dysfunction after cardiac surgery: a systematic review

AIMS

Postoperative cognitive dysfunction (POCD) is often experienced by cardiac surgery patients; however, it is not known if some groups of patients experience this more frequently or severely than others.The aim of this systematic review was to identify preoperative and postoperative predictors of cognitive dysfunction in adults following cardiac surgery.

METHODS AND RESULTS

Eight bibliographic databases were searched (January 2005 to March 2021) in relation to cardiac surgery and cognition. Studies including adult patients who had undergone open cardiac surgery and using a validated measurement of cognitive function were included. Full-text review for inclusion, quality assessment, and data extraction were undertaken independently by two authors.A total of 2870 papers were identified, of which 36 papers met the inclusion criteria and were included in the review. The majority were prospective observational studies [n = 28 (75.7%)]. In total, 61 independent predictors (45 preoperative and 16 postoperative) were identified as significant in at least one study; advancing age and education level appear important. Age has emerged as the most common predictor of cognitive outcome.

CONCLUSION

Although a number of predictors of POCD have been identified, they have inconsistently been reported as significantly affecting cognitive outcome. Consistent with previous research, our findings indicate that older patients and those with lower educational levels should be prioritized when developing and trialling interventions to improve cognitive function. These findings are less than surprising if we consider the methodological shortcomings of included studies. It is evident that further high-quality research exploring predictors of POCD is required.

Development and validation of a delirium risk prediction preoperative model for cardiac surgery patients (DELIPRECAS): An observational multicentre study

STUDY OBJECTIVE

To develop and validate a delirium risk prediction preoperative model for patients undergoing cardiac surgery.

DESIGN

Observational prospective multicentre study.

SETTING

Six intensive care units in Spain.

PATIENTS

689 patients undergoing cardiac surgery consecutively, aged ≥18 years.

MEASUREMENTS

The primary outcome measure was the development of delirium, diagnosed using the Confusion Assessment Method in Intensive Care Units (CAM-ICU), during the stay in the intensive care unit after cardiac surgery.

MAIN RESULTS

The model was developed with 345 consecutive patients undergoing cardiac surgery at six hospitals and validated with another 344 patients from the same hospitals. The prediction model contained four preoperative risk factors: age over 65 years, Mini-Mental State Examination (MMSE) score of 25-26 points (possible impairment of cognitive function) or < 25 (impairment of cognitive function), insomnia needing medical treatment and low physical activity (walk less than 30 min a day). The model had an area under the receiver operating characteristics curve of 0.825 (95% confidence interval: 0.76-0.89). The validation resulted in an area under the curve of 0.79 (0.73-0.85) and the pooled area under the receiver operating characteristics curve (n = 689) was 0.81 (0.76-0.85). We stratified patients in groups of low (0%-20%), moderate (> 20%-40%), high (> 40%-60%) and very high (> 60%) risk of developing delirium, with a positive and negative predictive value for the very high risk group of 70.97% and 85.56%, respectively.

CONCLUSION

The DELIPRECAS model (DELIrium PREvention CArdiac Surgery), consisting of four well-defined clinical risk factors, can predict in the preoperative period the risk of developing postoperative delirium in patients undergoing cardiac surgery. An automatic version of the risk calculator is available.

Effects of dexmedetomidine on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing minimally invasive coronary artery bypass surgery

OBJECTIVE

This study aimed to investigate the effects of dexmedetomidine on cerebral oxygen saturation [Sct(O2)] and postoperative cognitive function in elderly patients undergoing minimally invasive coronary artery bypass graft surgery.

METHODS

Sixty elderly patients who received minimally invasive coronary artery bypass graft surgery were randomly equally divided into dexmedetomidine group (group D) and control group (group N). The patients in group D were pumped with 1 μg/kg dexmedetomidine for 15 min before incision, followed by continuous pumping at 0.3-0.5 μg/(kg·h) till the end of the operation. The patients in group N received same dose of normal saline during the operation. Sct(O2) was monitored at pre-induction (T0), post-induction (T1), 30 min (T2) after single-lung ventilation, and after surgery (T3). Mini-mental state examination (MMSE) was used to assess the cognitive function at 1 day before, 72 hour and 7 days after surgery.

RESULTS

Sct(O2) level in group D was significantly higher than that in group N at T2 (P < 0.05). Sct(O2) level was statistically lower at T2 than that at T0, T1 and T3 in the same group N (P < 0.05). At 72 h and 7d after operation, the incidence of cognitive dysfunction in group D was markedly lower than that in group N (P < 0.05), the MMSE score in group D was markedly higher than those in group N, but was significantly lower than that before surgery (P < 0.05).

CONCLUSION

Dexmedetomidine can alleviate the decrease of Sct(O2) during single-lung ventilation, improve postoperative cognitive function, and reduce the incidence of POCD in elderly patients with minimally invasive coronary artery bypass surgery.

The "Aging Factor" Eotaxin-1 (CCL11) Is Detectable in Transfusion Blood Products and Increases with the Donor's Age

Background: High blood levels of the chemokine eotaxin-1 (CCL11) have recently been associated with aging and dementia, as well as impaired memory and learning in humans. Importantly, eotaxin-1 was shown to pass the blood-brain-barrier (BBB) and has been identified as crucial mediator of decreased neurogenesis and cognitive impairment in young mice after being surgically connected to the vessel system of old animals in a parabiosis model. It thus has to be assumed that differences in eotaxin-1 levels between blood donors and recipients might influence cognitive functions also in humans. However, it is unknown if eotaxin-1 is stable during processing and storage of transfusion blood components. This study assesses eotaxin-1 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC), and platelet concentrate (PC) in dependence of storage time as well as the donor’s age and gender.

Methods: Eotaxin-1 was measured in FFP (n = 168), EC (n = 160) and PC (n = 8) ready-to-use for transfusion employing a Q-Plex immunoassay for eotaxin-1. Absolute quantification of eotaxin-1 was performed with Q-view software.

Results: Eotaxin-1 was consistently detected at a physiological level in FFP and EC but not PC. Eotaxin-1 levels were comparable in male and female donors but increased significantly with rising age of donors in both, FFP and EC. Furthermore, eotaxin-1 was not influenced by storage time of either blood component. Finally, eotaxin-1 is subject to only minor fluctuations within one donor over a longer period of time.

Conclusion: Eotaxin-1 is detectable and stable in FFP and EC and increases with donor’s age. Considering the presumed involvement in aging and cognitive malfunction, differences in donor- and recipient eotaxin-1 levels might affect mental factors after blood transfusion.