Risk factors for postoperative delirium after cardiac surgical procedures with cardioplegic arrest

Risk Factors for Postanesthetic Emergence Delirium in Adults: A Systematic Review and Meta-analysis

Emergence delirium (ED) is delirium that occurs during or immediately after emergence from general anesthesia or sedation. Effective pharmacological treatments for ED are lacking, so preventive measures should be taken to minimize the risk of ED. However, the risk factors for ED in adults are unclear. In this systematic review and meta-analysis, we evaluated the evidence for risk factors for ED in adults. The PubMed, Scopus, Cochrane Library, Google Scholar, and Embase databases were searched for observational studies reporting the risk factors for ED in adults from inception to July 31, 2023. Twenty observational studies reporting 19,171 participants were included in this meta-analysis. Among the preoperative factors identified as risk factors for ED were age <40 or ≥65 years, male sex, smoking history, substance abuse, cognitive impairment, anxiety, and American Society of Anesthesiologists physical status score III or IV. Intraoperative risk factors for ED were the use of benzodiazepines, inhalational anesthetics, or etomidate, and surgical factors including abdominal surgery, frontal craniotomy (vs. other craniotomy approaches) for cerebral tumors, and the length of surgery. Postoperative risk factors were indwelling urinary catheters, the presence of a tracheal tube in the postanesthetic care unit or intensive care unit, the presence of a nasogastric tube, and pain. Knowledge of these risk factors may guide the implementation of stratified management and timely interventions for patients at high risk of ED. The majority of studies included in this review investigated only hyperactive ED and further research is required to determine risk factors for hypoactive and mixed ED types.

Preoperative Delirium Risk Screening in Patients Undergoing a Cardiac Surgery: Results from the Prospective Observational FINDERI Study

OBJECTIVE

Postoperative delirium (POD) is a common complication of cardiac surgery that is associated with higher morbidity, longer hospital stay, cognitive decline, and mortality. Preoperative assessments may help to identify patients´ POD risk. However, a standardized screening assessment for POD risk has not been established.

DESIGN

Prospective observational FINd DElirium RIsk factors (FINDERI) study.

PARTICIPANTS

Patients aged ≥50 years undergoing cardiac surgery.

MEASUREMENTS

The primary aim was to analyze the predictive value of the Delirium Risk Screening Questionnaire (DRSQ) prior to cardiac surgery. Secondary aims are to investigate cognitive, frailty, and geriatric assessments, and to use data-driven machine learning (ML) in predicting POD. Predictive properties were assessed using receiver operating characteristics analysis and multivariate approaches (regularized LASSO regression and decision trees).

RESULTS

We analyzed a data set of 504 patients (68.3 ± 8.2 years, 21.4% women) who underwent cardiac surgery. The incidence of POD was 21%. The preoperatively administered DRSQ showed an area under the curve (AUC) of 0.68 (95% CI 0.62, 0.73), and the predictive OR was 1.25 (95% CI 1.15, 1.35, p <0.001). Using a ML approach, a three-rule decision tree prediction model including DRSQ (score>7), Trail Making Test B (time>118), and Montreal Cognitive Assessment (score ≤ 22) was identified. The AUC of the three-rule decision tree on the training set was 0.69 (95% CI 0.63, 0.75) and 0.62 (95% CI 0.51, 0.73) on the validation set.

CONCLUSION

Both the DRSQ and the three-rule decision tree might be helpful in predicting POD risk before cardiac surgery.

Perioperative Blood Transfusion and Delirium after Total Knee or Hip Arthroplasty: Retrospective Analysis

We investigated the type of blood component transfusion associated with increased postoperative delirium. Adult patients who underwent total knee arthroplasty (TKA) or total hip arthroplasty (THA) between 2017 and 2022 were included. Delirium was evaluated and treated within two days after surgery. A total of 6737 patients (4112 TKA/2625 THA) were retrospectively studied; 2.48% of patients in the TKA (n = 102) and THA (n = 65) groups had postoperative delirium. The blood transfusion (BT) and non-BT groups had similar percentages of patients who experienced postoperative delirium (3.34 vs. 2.35%, p = 0.080). In the multivariable logistic regression model, BT was not associated with postoperative delirium-adjusted odds ratio (aOR): 1.03, confidence interval (CI): 0.62, 1.71; p = 0.917. Moreover, transfusion of packed red blood cells (p = 0.651), platelets (p = 0.998), and cryoprecipitate (p = 0.999) were not associated with delirium. However, transfusion of fresh frozen plasma was associated with a 5.96-fold higher incidence of delirium-aOR: 5.96, 95% CI: 2.72, 13.04; p < 0.001. In conclusion, perioperative BT was not associated with postoperative delirium in patients who underwent TKA or THA. However, FFP transfusion was associated with an increased incidence of postoperative delirium.

Incidence and risk factors of postoperative delirium following hepatic resection: a retrospective national inpatient sample database study

BACKGROUND

Postoperative delirium (POD) is a common complication after major surgery and can cause a variety of adverse effects. However, no large-scale national database was used to assess the occurrence and factors associated with postoperative delirium (POD) following hepatic resection.

METHODS

Patients who underwent hepatic resection from 2015 to 2019 were screened using the International Classification of Diseases (ICD) 10th edition clinical modification code from the National Inpatient Sample (NIS) Database. Peri-operative factors associated with delirium were screened and underwent statistical analysis to identify independent predictors for delirium following hepatic resection.

RESULTS

A total of 80,070 patients underwent hepatic resection over a five-year period from 2015 to 2019. The overall occurrence of POD after hepatic resection was 1.46% (1039 cases), with a slight upward trend every year. The incidence of elective admission was 6.66% lower (88.60% vs. 81.94%) than that of patients without POD after hepatic resection and 2.34% (45.53% vs. 43.19%) higher than that of patients without POD in teaching hospitals (P < 0.001). In addition, POD patients were 6 years older (67 vs. 61 years) and comprised 9.27% (56.69% vs. 47.42%) more male patients (P < 0.001) compared to the unaffected population. In addition, the occurrence of POD was associated with longer hospitalization duration (13 vs. 5 days; P < 0.001), higher total cost ($1,481,89 vs. $683,90; P < 0.001), and higher in-hospital mortality (12.61% vs. 4.11%; P < 0.001). Multivariate logistic regression identified hepatic resection-independent risk factors for POD, including non-elective hospital admission, teaching hospital, older age, male sex, depression, fluid and electrolyte disorders, coagulopathy, other neurological disorders, psychoses, and weight loss. In addition, the POD after hepatic resection has been associated with sepsis, dementia, urinary retention, gastrointestinal complications, acute renal failure, pneumonia, continuous invasive mechanical ventilation, blood transfusion, respiratory failure, and wound dehiscence / non-healing.

CONCLUSION

Although the occurrence of POD after hepatic resection is relatively low, it is beneficial to investigate factors predisposing to POD to allow optimal care management and improve the outcomes of this patient population.

Lower alpha frequency of intraoperative frontal EEG is associated with postoperative delirium: A secondary propensity-matched analysis

BACKGROUND

Postoperative delirium (POD) is a serious complication of surgery, especially in the elderly patient population. It has been proposed that decreasing the amount of anesthetics by titrating to an EEG index will lower POD rate, but clear evidence is missing. A strong age-dependent negative correlation has been reported between the peak oscillatory frequency of alpha waves and end-tidal anesthetic concentration, with older patients generating slower alpha frequencies. We hypothesized, that slower alpha oscillations are associated with a higher rate of POD.

METHOD

Retrospective analysis of patients` data from a prospective observational study in cardiac surgical patients approved by the Bernese Ethics committee. Frontal EEG was recorded during Isoflurane effect-site concentrations of 0.7 to 0.8 and peak alpha frequency was measured at highest power between 6 and 17 Hz. Delirium was assessed by chart review. Demographic and clinical characteristics were compared between POD and non-POD groups. Selection bias was addressed using nearest neighbor propensity score matching (PSM) for best balance. This incorporated 18 variables, whereas patients with missing variable information or without an alpha oscillation were excluded.

RESULT

Of the 1072 patients in the original study, 828 were included, 73 with POD, 755 without. PSM allowed 328 patients into the final analysis, 67 with, 261 without POD. Before PSM, 8 variables were significantly different between POD and non-POD groups, none thereafter. Mean peak alpha frequency was significantly lower in the POD in contrast to non-POD group before and after matching (7.9 vs 8.9 Hz, 7.9 vs 8.8 Hz respectively, SD 1.3, p < 0.001).

CONCLUSION

Intraoperative slower frontal peak alpha frequency is independently associated with POD after cardiac surgery and may be a simple intraoperative neurophysiological marker of a vulnerable brain for POD. Further studies are needed to investigate if there is a causal link between alpha frequency and POD.

The role of perioperative sedative anesthetics in preventing postoperative delirium: a systematic review and network-meta analysis including 6679 patients

OBJECTIVE

Postoperative delirium is a common and debilitating complication that significantly affects patients and their families. The purpose of this study is to investigate whether there is an effective sedative that can prevent postoperative delirium while also examining the safety of using sedatives during the perioperative period.

METHODS

The net-meta analysis was used to compare the incidence of postoperative delirium among four sedatives: sevoflurane, propofol, dexmedetomidine, and midazolam. Interventions were ranked according to their surface under the cumulative ranking curve (SUCRA).

RESULTS

A total of 41 RCT studies involving 6679 patients were analyzed. Dexmedetomidine can effectively reduce the incidence of postoperative delirium than propofol (OR 0.47 95% CI 0.25-0.90), midazolam (OR 0.42 95% CI 0.17-1.00), normal saline (OR 0.42 95% CI 0.33-0.54) and sevoflurane (OR 0.39 95% CI 0.18-0.82). The saline group showed a significantly lower incidence of bradycardia compared to the group receiving dexmedetomidine (OR 0.55 95% CI 0.37-0.80). In cardiac surgery, midazolam (OR 3.34 95%CI 2.04-5.48) and normal saline (OR 2.27 95%CI 1.17-4.39) had a higher rate of postoperative delirium than dexmedetomidine, while in non-cardiac surgery, normal saline (OR 1.98 95%CI 1.44-2.71) was more susceptible to postoperative delirium than dexmedetomidine.

CONCLUSION

Our analysis suggests that dexmedetomidine is an effective sedative in preventing postoperative delirium whether in cardiac surgery or non-cardiac surgery. The preventive effect of dexmedetomidine on postoperative delirium becomes more apparent with longer surgical and extubation times. However, it should be administered with caution as it was found to be associated with bradycardia.

Identification of early delirium and its outcomes after cardiopulmonary bypass among adult patients with cardiovascular disease: a prospective observational study

Purpose

To identify the incidence and outcomes of postoperative delirium after cardiopulmonary bypass machine in adult cardiac surgery patients.

Method

A prospective observational study was conducted in a single-center institution in the Republic of China. This study included 273 patients who underwent cardiac surgical procedures requiring cardiopulmonary bypass machine utilization.

Results

This study used the Confusion Assessment Method to screen for delirium. Univariate analysis identified advanced age, emergency surgery and prolonged aortic cross-clamping time as significant predisposing factors for delirium, which occurred in 19.8% (n = 54) of cases and typically developed in average of 4.8 ± 3.28 days after the surgery. The analysis also identified that delirium was associated with increased complications and external referrals. A total of 142 patients (52.1%) were discharged to their homes, wherein the discharge rate in the delirium group was notably lower, with only 35.2% (n = 19) of patients, than in the delirium-free group with 56.2% (n = 123) of patients.

Conclusion

Considering the increased probability of delirium-related complications following cardiac surgery, it is important to develop effective preventive strategies for patients with perioperative risk factors, such as advanced age, emergency surgery and prolonged cross-clamp time, by implementing practical measures to minimize the risk of delirium.

Target flow deviations on the cardiopulmonary bypass cause postoperative delirium in cardiothoracic surgery-a retrospective study evaluating temporal fluctuations of perfusion data

OBJECTIVES

Postoperative delirium (POD) is common, costly and associated with long-term morbidity and increased mortality. We conducted a cohort study to assess the contribution of cardiopulmonary bypass (CPB) to the development of POD by means of algorithm-based data processing.

METHODS

A database was compiled from 3 datasets of patients who underwent cardiac surgery between 2014 and 2019: intensive care unit discharge files, CPB protocols and medical quality management records. Following data extraction and structuring using novel algorithms, missing data were imputed. Ten independent imputations were analysed by multiple logistic regression with stepwise deletion of factors to arrive at a minimal adequate model.

RESULTS

POD was diagnosed in 456/3163 patients (14.4%). In addition to known demographic risk factors and comorbidities like male sex, age, carotid disease, acute kidney failure and diabetes mellitus, cardiopulmonary parameters like total blood volume at the CPB [adjusted odds ratio (AOR) 1.001; confidence interval (CI) 1.1001-1.002] were independent predictors of POD. Higher values of the minimal blood flow were associated with a lower risk of POD (AOR 0.993; CI 0.988-0.997). Flow rates at least 30% above target did emerge in the minimal adequate model as a potential risk factor, but the confidence interval suggested a lack of statistical significance (AOR 1.819; 95% CI: 0.955-3.463).

CONCLUSIONS

CPB data processing proved to be a useful tool for obtaining compact information to better identify the roles of individual operational states. Strict adherence to perfusion limits along with tighter control of blood flow and acid-base balance during CPB may help to further decrease the risk of POD.

Online interpretable dynamic prediction models for postoperative delirium after cardiac surgery under cardiopulmonary bypass developed based on machine learning algorithms: A retrospective cohort study

OBJECTIVE

Postoperative delirium (POD) is strongly associated with poor early and long-term prognosis in cardiac surgery patients with cardiopulmonary bypass (CPB). This study aimed to develop dynamic prediction models for POD after cardiac surgery under CPB using machine learning (ML) algorithms.

METHODS

From July 2021 to June 2022, clinical data were collected from patients undergoing cardiac surgery under CPB at Nanjing First Hospital. A dataset from the same center (October 2022 to November 2022) was also used for temporal external validation. We used ML and deep learning to build models in the training set, optimized parameters in the test set, and finally validated the best model in the validation set. The SHapley Additive exPlanations (SHAP) method was introduced to explain the best models.

RESULTS

Of the 885 patients enrolled, 221 (25.0%) developed POD. 22 (22.0%) of 100 validation cohort patients developed POD. The preoperative and postoperative artificial neural network (ANN) models exhibited optimal performance. The validation results demonstrated satisfactory predictive performance of the ANN model, with area under the receiver operator characteristic curve (AUROC) values of 0.776 and 0.684 for the preoperative and postoperative models, respectively. Based on the ANN algorithm, we constructed dynamic, highly accurate, and interpretable web risk calculators for POD.

CONCLUSIONS

We successfully developed online interpretable dynamic ANN models as clinical decision aids to identify patients at high risk of POD before and after cardiac surgery to facilitate early intervention or care.

The Association of Infection with Delirium in the Post-Operative Period after Elective CABG Surgery

Delirium is one of the most common complications of coronary artery by-pass graft (CABG) surgery. The identification of patients at increased risk of delirium and the implementation of preventive measures to reduce the risk of postoperative delirium is necessary to improve treatment outcomes after CABG. The aim of this study was to assess the association between postoperative delirium and postoperative infection and 10-year mortality in patients undergoing CABG surgery. This is a retrospective, observational cohort study of patients undergoing planned on-pump CABG between April 2010 and December 2012. We analysed a group of 3098 patients operated on in our cardiac surgery centre, from whom we selected a cohort of patients undergoing planned CABG surgery. All patients were assessed for postoperative infection, such as pneumonia, bloodstream infections (BSIs) and surgical site infections (SSIs). Patients who experienced postoperative delirium were significantly more likely to have infection (7.4% vs. 22%; p = 0.0037). As regards particular types of infection, significant differences were only found for pneumonia and sternal SSIs. Patients who experienced postoperative delirium had significantly lower 5-year (p = 0.0136) and 10-year (p = 0.0134) survival. Postoperative delirium significantly increases long-term mortality in patients undergoing CABG surgery. Pneumonia and sternal SSIs significantly increase the risk of postoperative delirium in cardiac surgery patients.

Standardized pharmacological management of delirium after on-pump cardiac surgery reduces ICU stay and ventilation in a retrospective pre-post study

Cardiac surgery patients not only undergo a highly invasive procedure but are at risk for a diversity of postoperative complications. Up to 53% of these patients suffer from postoperative delirium (POD). This severe and common adverse event increases mortality and prolonged mechanical ventilation and extends the intensive care unit stay. The objective of this study was to test the hypothesis that standardized pharmacological management of delirium (SPMD) may reduce the length of stay in the intensive care unit (ICU), duration of postoperative mechanical ventilation, and the incidence of postoperative complications such as pneumonia or bloodstream infections in on-pump cardiac surgery ICU patients. In this retrospective, single-center observational cohort study, 247 patients were examined between May 2018 to June 2020, who underwent on-pump cardiac surgery, suffered from POD, and received pharmacological POD treatment. 125 were treated before and 122 after SPMD implementation in the ICU. The primary endpoint was a composite outcome, including the length of ICU stay, postoperative mechanical ventilation time, and ICU survival rate. The secondary endpoints were complications including postoperative pneumonia and bloodstream infections. Although the ICU survival rate was not significantly different between both groups, the length of ICU stay (control group: 23 ± 27 days; SPMD group: 16 ± 16 days; p = 0.024) and the duration of mechanical ventilation were significantly reduced in the SPMD-cohort (control group: 230 ± 395 h; SPMD group: 128 ± 268 h; p = 0.022). Concordantly, the pneumonic risk was reduced after SPMD introduction (control group: 44.0%; SPMD group: 27.9%; p = 0.012) as well as the incidence for bloodstream infections (control group: 19.2%; SPMD group: 6.6%; p = 0.004). Standardized pharmacological management of postoperative delirium in on-pump cardiac surgery ICU patients reduced the length of ICU stay and duration of mechanical ventilation significantly, leading to a decrease in pneumonic complications and bloodstream infections.

Influence of cardioplegic solution on incidence of delirium after CABG surgery: Use of Calafiore blood cardioplegia versus HTK - Bretschneider - solution in a single-center retrospective analysis from 2017 to 2021

BACKGROUND

Purpose of the present study is an evaluation of postoperative incidence for delirium after coronary artery bypass surgery (CABG). Study addressed whether application of Histidine-Tryptophan-Ketoglutarate (HTK) solution (Bretschneider) or blood cardioplegia (Calafiore) is associated with increased of postoperative delirium cases.

MATERIALS AND METHODS

In a retrospective, single center evaluation a total number of 273 patients were enrolled in the study from January 2017 to October 2021. There were 124 patients assigned to the Calafiore group blood cardioplegic solution (BCC) and 149 patients were included in the Bretschneider group (HTK). The primary endpoint was the postoperative delirium rate in its frequency of occurrence. Definition of the dilirium status was performed using the Confusion Assessment Method in the Intensive Care Unit (CAM-ICU) score during the first three postoperative days. Secondary endpoints were the time intervals of intensive care duration of stay, mechanical ventilation, total extracorporeal circulation, ischemia and reperfusion. Serum levels of the electrolytes Sodium, Potassium, ionized Calcium, and Chloride were monitored.

RESULTS

Although no significant difference in delirium status between the groups were noticed, on third postoperative day, delirium rate dependent on cardioplegia solution used (HTK 12.0%; BCC 3.0%; p = .024) and duration of intensive care stay differed (HTK 4.5 vs. BCC 3.0 days; p = .001). Although Ischemic time (HTK 73.0 vs. BCC 83.0 min; p < .001) and reperfusion time (HTK 35.0 vs. Calafiore 24.0 min; p < .001) were extended in the BCC group less cases of delirium were diagnosed. Serum sodium levels after HTK cardioplegic infusion were decreased (HTK 129.68 vs. BCC 138.96 mmol/l; p < .001). The significant difference persists up to the hundredth extracorporeal circulation circuit min (p = .005).

CONCLUSION

The present data suggest an impact of the cardioplegic solution used upon postoperative delirium rates. Optimization of cardiac arrest protocols is needed. Present data encourage further prospective studies regarding the impact of cardioplegic solutions on electrolyte imbalance for postoperative delirium rates in CABG surgery.