Risk factors and associated outcomes of postoperative delirium after open abdominal aortic aneurysm repair

OBJECTIVE

Open abdominal aortic aneurysm repair (OAR) is a major vascular procedure that incurs a large physiologic demand, increasing the risk for complications such as postoperative delirium (POD). We sought to characterize POD incidence, identify delirium risk factors, and evaluate the effect of delirium on postoperative outcomes. We hypothesized that POD following OAR would be associated with increased postoperative complications and resource utilization.

METHODS

This was a retrospective study of all OAR cases from 2012 to 2020 at a single tertiary care center. POD was identified via a validated chart review method based on key words and Confusion Assessment Method assessments. The primary outcome was POD, and secondary outcomes included length of stay, non-home discharge, 90-day mortality, and 1-year survival. Bivariate analysis as appropriate to the data was used to assess the association of delirium with postoperative outcomes. Multivariable binary logistic regression was used to identify risk factors for POD and Cox regression for variables associated with worse 1-year survival.

RESULTS

Overall, 198 OAR cases were included, and POD developed in 34% (n = 67). Factors associated with POD included older age (74 vs 69 years; P < .01), frailty (50% vs 28%; P < .01), preoperative dementia (100% vs 32%; P < .01), symptomatic presentation (47% vs 27%; P < .01), preoperative coronary artery disease (44% vs 28%; P = .02), end-stage renal disease (89% vs 32%; P < .01) and Charlson Comorbidity Index score >4 (42% vs 26%; P = .01). POD was associated with 90-day mortality (19% vs 5%; P < .01), non-home discharge (61% vs 30%; P < .01), longer median hospital length of stay (14 vs 8 days; P < .01), longer median intensive care unit length of stay (6 vs 3 days; P < .01), postoperative myocardial infarction (7% vs 2%; P = .045), and postoperative pneumonia (19% vs 8%; P = .01). On multivariable analysis, risk factors for POD included older age, history of end-stage renal disease, lack of epidural, frailty, and symptomatic presentation. A Cox proportional hazards model revealed that POD was associated with worse survival at 1 year (hazard ratio, 3.8; 95% confidence interval, 1.6-9.0; P = .003).

CONCLUSIONS

POD is associated with worse postoperative outcomes and increased resource utilization. Future studies should examine the role of improved screening, implementation of delirium prevention bundles, and multidisciplinary care for the most vulnerable patients undergoing OAR.

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.

Effects of inflammation and oxidative stress on postoperative delirium in cardiac surgery

The past decade has witnessed unprecedented medical progress, which has translated into cardiac surgery being increasingly common and safe. However, complications such as postoperative delirium remain a major concern. Although the pathophysiological changes of delirium after cardiac surgery remain poorly understood, it is widely thought that inflammation and oxidative stress may be potential triggers of delirium. The development of delirium following cardiac surgery is associated with perioperative risk factors. Multiple interventions are being explored to prevent and treat delirium. Therefore, research on the potential role of biomarkers in delirium as well as identification of perioperative risk factors and pharmacological interventions are necessary to mitigate the development of delirium.

Postoperative Delirium in Lung Cancer Anatomical Resection-Analysis of Risk Factors and Prognosis

BACKGROUND

The incidence of postoperative delirium after anatomical lung resection ranges from 5 to 16%. This study aimed to analyze the risk factors and prognosis of postoperative delirium in anatomical lung resection for lung cancer.

METHODS

This study included 1351 patients undergoing anatomical lung resection between April 2010 and October 2020. We analyzed the perioperative risk factors of postoperative delirium. We also compared postoperative complications and survival between the delirium and non-delirium groups.

RESULTS

Postoperative delirium was identified in 44 (3.3%) of 1351 patients who underwent anatomical lung resection for lung cancer. Age, peripheral vascular disease, depression, and current smoking status were independent risk factors for postoperative delirium in the multivariate analysis. The percentage of postoperative delirium was 0.6% in never smokers and 6.0% in current smokers. The delirium and non-delirium groups showed significant differences in overall survival (p = 0.0144) and non-disease-specific survival (p = 0.0080). After propensity score matching, the two groups did not significantly differ in overall survival (p = 0.9136), non-disease-specific survival (p = 0.8146), or disease-specific survival (p = 0.6804).

CONCLUSIONS

Age, peripheral vascular disease, depression, and current smoking status were considered independent risk factors for postoperative delirium in anatomical lung resection for lung cancer. Smoking cessation for at least four weeks before surgery is recommended for reducing incidence of post-operative delirium.

Association between ankle brachial index and development of postoperative intensive care unit delirium in patients with peripheral arterial disease

Patients with vascular diseases are prone to developing postoperative delirium (POD). Ankle brachial index (ABI) is a non-invasive clinical indicator of lower-extremities peripheral arterial disease (PAD) and has been identified as an indicator of cognitive impairment. We investigated the association between ABI and POD. 683 PAD patients who underwent elective leg arterial bypass surgery between October 1998 and August 2019 were collected for retrospective analysis. Demographic information, comorbidities, preoperative ABI and the Rutherford classification within one month prior to surgery were obtained. POD was assessed using the Confusion assessment method -intensive care unit. Logistic regression and receiver operating characteristics (ROC) curve analysis were used to assess the association between ABI and POD. The mean value of ABI was significantly lower in patients with POD than it was those without POD. Older age, more medical comorbidities, longer length of surgery, decreased ABI, and higher Rutherford class were all significantly associated with POD. The area under ROC (0.74) revealed that ABI below 0.35 was associated with development of POD. Lower preoperative ABI was associated with POD in PAD patients who underwent arterial bypass surgery.

Risk Factors for Delirium after Vascular Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Vascular surgery is considered a risk factor for the development of postoperative delirium (POD). In this systematic review we provide a report on the incidence and risk-factors of POD after vascular surgery.

METHODS

A systematic literature search was conducted using Pubmed with the MeSH terms and key words "delirium" or "confusion", "vascular surgery procedures" and "risk factors or "risk assessment". Studies were selected for review after meeting the following inclusion criteria: vascular surgery, POD diagnosed using validated screening tools, and DSM-derived criteria to assess delirium. A meta-analysis was performed for each endpoint if at least two studies could be combined.

RESULTS

Sixteen articles met the abovementioned criteria. The incidence of delirium ranged from 5% to 39%. Various preoperative risk factors were identified that is, age (Random MD 3.96, CI 2.57-5.35), hypertension (Fixed OR 1.30, CI 1.05-1.59), diabetes mellitus (Random OR 2.15, CI 1.30-3.56), hearing impairment (Fixed OR 1.89, CI 1.28-2.81), history of cerebrovascular incident or transient ischemic attack (Fixed OR 2.20, CI 1.68-2.88), renal failure (Fixed OR 1.61, CI 1.19-2.17), and pre-operative low haemoglobin level (fixed MD -0.76, CI -1.04 to -0.47). Intra-operative risk factors were duration of surgery (Random MD 15.68; CI 2.79-28.57), open aneurysm repair (Fixed OR 4.99, CI 3.10-8.03), aortic cross clamping time (fixed MD 7.99, CI 2.56-13.42), amputation surgery (random OR 3.77, CI 2.13-6.67), emergency surgery (Fixed OR 4.84, CI 2.81-8.32) and total blood loss (Random MD 496.5, CI 84.51-908.44) and need for blood transfusion (Random OR 3.72, CI 1.57-8.80). Regional anesthesia on the other hand, had a protective effect. Delirium was associated with longer ICU and hospital length of stay, and more frequent discharge to a care facility.

CONCLUSIONS

POD after vascular surgery is a frequent complication and effect-size pooling supports the concept that delirium is a heterogeneous disorder. The risk factors identified can be used to either design a validated risk factor model or individual preventive strategies for high-risk patients.

Risk factors of post-operative delirium after elective vascular surgery in the elderly: A systematic review

BACKGROUND

Postoperative delirium is a common and serious adverse event in the elderly patient and is associated with significant morbidity and mortality. It is of great importance to identify patients at risk for delirium, in order to focus preventive strategies. The aim of this article is to systematically review current available literature on pre-operative risk factors for delirium after vascular surgery.

METHODS

A systematic literature search was conducted using PubMed and EMBASE, using the MeSH terms and key words "delirium", "surgery" and "risk factor". Studies were retained for review after meeting strict inclusion criteria that included only prospective studies evaluating risk factors for delirium in patients who had elective vascular surgery. Diagnosis of delirium needed to be confirmed using the Diagnostic and Statistical Manual of Mental Disorders (DSM) or ICD-10.

RESULTS

Fifteen articles were selected for inclusion, incidence of delirium across the studies ranged from 5% to 39%. Many factors have been associated with increased risk of delirium, including age, cognitive impairment, comorbidity, depression, smoking, alcohol, visual and hearing impairment, ASA-score, biochemical abnormalities, operative strategies and blood loss.

CONCLUSIONS

Delirium is a common complication after elective vascular surgery in elderly. The highest delirium incidence was observed after open aortic surgery as well as after surgery for critical limb ischemia. A picture starts to form of which predisposing factors lead to increased risk of delirium. The leading risk factors consistently identified in this systematic review were advanced age and cognitive impairment. Multi-disciplinary specialist-led interventions in the preoperative phase could decrease incidence and severity of delirium and should be focused on identified high-risk patients.

New aspects of delirium in elderly patients with critical limb ischemia

Objective

The primary objective was to identify possible risk factors for delirium in patients with critical limb ischemia undergoing surgery. The secondary objective was to study the effect of delirium on complications, the length of hospital stay, health care costs, and mortality.

Methods

All patients 65 years or older with critical limb ischemia undergoing surgery from February 2013 to July 2014 at Amphia Hospital, were included and followed up until December 31, 2014. Delirium was scored using the Delirium Observation Screening Scale (DOSS). Perioperative risk factors (age, comorbidity, factors of frailty, operation type, hemoglobulin, and transfusion) were collected and analyzed using logistic regression. Secondary outcomes were the number of complications, total hospital stay, extra health care costs per delirium, and mortality within 3 months and 6 months of surgery.

Results

We included 92 patients with critical limb ischemia undergoing surgery. Twenty-nine (32%) patients developed a delirium during admission, of whom 17 (59%) developed delirium preoperatively. After multivariable analysis, only diabetes mellitus (odds ratio [OR] =6.23; 95% confidence interval [CI]: 1.11–52.2; P=0.035) and Short Nutritional Assessment Questionnaire for Residential Care (SNAQ-RC) ≥3 (OR =5.55; 95% CI: 1.07–42.0; P=0.039) was significantly associated with the onset of delirium. Delirium was associated with longer hospital stay (P=0.001), increased health care costs, and higher mortality after 6 months (P<0.001).

Conclusion

Delirium is a common adverse event in patients with critical limb ischemia undergoing surgery with devastating outcome in the long term. Most patients developed delirium preoperatively, which indicates the need for early recognition and preventive strategies in the preoperative period. This study identified undernourishment and diabetes mellitus as independent risk factors for delirium.

Smoking increases the risk of delirium for older inpatients: a prospective population-based study

OBJECTIVES

To investigate the association between smoking in the older population and the risk of inpatient delirium, which is common and has adverse consequences.

METHOD

Participants (N=3754) were insurants aged ≥55years of the largest German statutory health insurance company, who enrolled in a 6-year prospective population-based study. Baseline smoking, adjusted for age, sex, depressive symptoms, cognitive impairment and alcohol consumption, was analyzed as risk factor of inpatient delirium. Results are presented as hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

Three-hundred seventy-three (10.0%) participants were smokers at baseline, 865 (23.0%) were quitters and 2516 (67.0%) were lifelong abstainers. Mean pack-years of smokers and quitters were 23.8 (S.D.=22.4). Sixty-one (1.6%) received a diagnosis of inpatient delirium. Smokers had an increased risk of delirium compared to abstainers in the fully adjusted model (HR=2.87, 95% CI 1.24-6.66). Quitters and abstainers did not differ (HR=0.79, 95% CI 0.37-1.72). Comparing smokers and quitters, current smoking status (HR=3.22, 95% CI 1.20-8.62) but not pack-years [residual χ(2)(1)=0.25, P=.874] were associated with inpatient delirium.

CONCLUSION

Only current smoking but not being a quitter and the lifetime amount smoked were associated with inpatient delirium, indicating that acute nicotine withdrawal may represent a relevant pathogenic mechanism.

Predicting postoperative delirium after vascular surgical procedures

OBJECTIVE

The objective of this study was to determine the incidence of and specific preoperative and intraoperative risk factors for postoperative delirium (POD) in electively treated vascular surgery patients.

METHODS

Between March 2010 and November 2013, all vascular surgery patients were included in a prospective database. Various preoperative, intraoperative, and postoperative risk factors were collected during hospitalization. The primary outcome variable was the incidence of POD. Secondary outcome variables were any surgical complication, hospital length of stay, and mortality.

RESULTS

In total, 566 patients were prospectively evaluated; 463 patients were 60 years or older at the time of surgery and formed our study cohort. The median age was 72 years (interquartile range, 66-77), and 76.9% were male. Twenty-two patients (4.8%) developed POD. Factors that differed significantly by univariate analysis included current smoking (P = .001), increased comorbidity (P = .001), hypertension (P = .003), diabetes mellitus (P = .001), cognitive impairment (P < .001), open aortic surgery or amputation surgery (P < .001), elevated C-reactive protein level (P < .001), and blood loss (P < .001). Multivariate logistic regression analysis revealed preoperative cognitive impairment (odds ratio [OR], 16.4; 95% confidence interval [CI], 4.7-57.0), open aortic surgery or amputation surgery (OR, 14.0; 95% CI, 3.9-49.8), current smoking (OR, 10.5; 95% CI, 2.8-40.2), hypertension (OR, 7.6; 95% CI, 1.9-30.5) and age ≥80 years (OR, 7.3; 95% CI, 1.8-30.1) to be independent predictors of the occurrence of POD. The combination of these parameters allows us to predict delirium with a sensitivity of 86% and a specificity of 92%. The area under the curve of the corresponding receiver operating characteristics was 0.93. Delirium was associated with longer hospital length of stay (P < .001), more frequent and increased intensive care unit stays (P = .008 and P = .003, respectively), more surgical complications (P < .001), more postdischarge institutionalization (P < .001), and higher 1-year mortality rates (P = .0026).

CONCLUSIONS

In vascular surgery patients, preoperative cognitive impairment and open aortic or amputation surgery were highly significant risk factors for the occurrence of POD. In addition, POD was significantly associated with a higher mortality and more institutionalization. Patients with these risk factors should be considered for high-standard delirium care to improve these outcomes.