Postoperative Delirium: A Review of Risk Factors and Tools of Prediction

Incidence change of postoperative delirium after implementation of processed electroencephalography monitoring during surgery: a retrospective evaluation study

BACKGROUND

Postoperative delirium (POD) is a common complication in the elderly, which is associated with poor outcomes after surgery. Recognized as predisposing factors for POD, anesthetic exposure and burst suppression during general anesthesia can be minimized with intraoperative processed electroencephalography (pEEG) monitoring. In this study, we aimed to evaluate whether implementation of intraoperative pEEG-guided anesthesia is associated with incidence change of POD.

METHODS

In this retrospective evaluation study, we analyzed intravenous patient-controlled analgesia (IVPCA) dataset from 2013 to 2017. There were 7425 patients using IVPCA after a noncardiac procedure under general anesthesia. Patients incapable of operating the device independently, such as cognitive dysfunction or prolonged sedation, were declined and not involved in the dataset. After excluding patients who opted out within three days (N = 110) and those with missing data (N = 24), 7318 eligible participants were enrolled. Intraoperative pEEG has been implemented since July 2015. Participants having surgery after this time point had intraoperative pEEG applied before induction until full recovery. All related staff had been trained in the application of pEEG-guided anesthesia and the assessment of POD. Patients were screened twice daily for POD within 3 days after surgery by staff in the pain management team. In the first part of this study, we compared the incidence of POD and its trend from 2013 January-2015 July with 2015 July-2017 December. In the second part, we estimated odds ratios of risk factors for POD using multivariable logistic regression in case-control setting.

RESULTS

The incidence of POD decreased from 1.18 to 0.41% after the administration of intraoperative pEEG. For the age group ≧ 75 years, POD incidence decreased from 5.1 to 1.56%. Further analysis showed that patients with pEEG-guided anesthesia were associated with a lower odd of POD (aOR 0.33; 95% CI 0.18-0.60) than those without after adjusting for other covariates.

CONCLUSIONS

Implementation of intraoperative pEEG was associated with a lower incidence of POD within 3 days after surgery, particularly in the elderly. Intraoperative pEEG might be reasonably considered as part of the strategy to prevent POD in the elder population.

TRIAL REGISTRATION

Not applicable.

Psychotherapy: A tool to prevent postoperative delirium?

The value of psychotherapy in surgical patients suffering from postoperative delirium is unclear. Options for the treatment of established postoperative delirium are few; therapy largely relies on the avoidance of postoperative delirium facilitating factors, like specific drugs and environmental factors in the perioperative setting. Established medical therapies' efficacy in terms of decreasing incidence of postoperative delirium is very low. The aim of this project is to suggest new therapeutic options in the form of cognitive behavioural therapy as a possible preventive and psychotherapeutic treatment of postoperative delirium. Life expectancy in developed countries increases worldwide and both the need for surgical treatment and the probability of postoperative delirium occurrence increase with age. Due to the necessity of addressing the individual's negative consequences of postoperative delirium and to optimise socioeconomical needs, new therapeutic options for the treatment of postoperative delirium are desperately needed.

Outcomes in Post-operative Delirium Following Bowel Resection: A Single Center Retrospective Review

INTRODUCTION

Delirium is associated with adverse post-operative outcomes, long-term cognitive dysfunction, and prolonged hospitalization. Risk factors for its development include longer surgical duration, increased operative complexity and invasiveness, and medical comorbidities. This study aims to further evaluate the incidence of delirium and its impact on outcomes among patients undergoing both elective and emergency bowel resections.

METHODS

This is a retrospective cohort study using an institutional patient registry. All patients undergoing bowel resection over a 3.5-year period were included. The study measured the incidence of post-operative delirium via the nursing confusion assessment method. This incidence was then compared to patient age, emergency versus elective admission, length of stay, mortality, discharge disposition, and hospital cost.

RESULTS

A total of 1934 patients were included with an overall delirium incidence of 8.8%. Compared to patients without delirium, patients with delirium were more likely to have undergone emergency surgery, be greater than 70 y of age, have a longer length of stay, be discharged to a skilled nursing facility, and have a more expensive hospitalization. In addition, the overall mortality was 14% in patients experiencing delirium versus 0.1% in those that did not. Importantly, when broken down between elective and emergency groups, the mortality of those experiencing delirium was similar (11 versus 13%).

CONCLUSIONS

The development of delirium following bowel resection is an important risk factor for worsened outcomes and mortality. Although the incidence of delirium is higher in the emergency surgery population, the development of delirium in the elective population infers a similar risk of mortality.

Validation of a delirium predictive model in patients admitted to surgical intensive care units: a multicentre prospective observational cohort study

OBJECTIVE

To internally and externally validate a delirium predictive model for adult patients admitted to intensive care units (ICUs) following surgery.

DESIGN

A prospective, observational, multicentre study.

SETTING

Three university-affiliated teaching hospitals in Thailand.

PARTICIPANTS

Adults aged over 18 years were enrolled if they were admitted to a surgical ICU (SICU) and had the surgery within 7 days before SICU admission.

MAIN OUTCOME MEASURES

Postoperative delirium was assessed using the Thai version of the Confusion Assessment Method for the ICU. The assessments commenced on the first day after the patient's operation and continued for 7 days, or until either discharge from the ICU or the death of the patient. Validation was performed of the previously developed delirium predictive model: age+(5×SOFA)+(15×benzodiazepine use)+(20×DM)+(20×mechanical ventilation)+(20×modified IQCODE>3.42).

RESULTS

In all, 380 SICU patients were recruited. Internal validation on 150 patients with the mean age of 75±7.5 years resulted in an area under a receiver operating characteristic curve (AUROC) of 0.76 (0.683 to 0.837). External validation on 230 patients with the mean age of 57±17.3 years resulted in an AUROC of 0.85 (0.789 to 0.906). The AUROC of all validation cohorts was 0.83 (0.785 to 0.872). The optimum cut-off value to discriminate between a high and low probability of postoperative delirium in SICU patients was 115. This cut-off offered the highest value for Youden's index (0.50), the best AUROC, and the optimum values for sensitivity (78.9%) and specificity (70.9%).

CONCLUSIONS

The model developed by the previous study was able to predict the occurrence of postoperative delirium in critically ill surgical patients admitted to SICUs.

TRIAL REGISTRATION NUMBER

Thai Clinical Trail Registry (TCTR20180105001).

Evidence-Based Guideline on Management of Postoperative Delirium in Older People for Low Resource Setting: Systematic Review Article

Background

Postoperative delirium is the highest prevalence and life-threatening complication following geriatric surgery. The overall incidence rate varies from 5% to 52% of hospitalized surgical patients based on the type of surgery that often began in the postanesthesia care unit and continues up to 5 days post-surgery. Postoperative delirium manifests as a hypoactive, hyperactive and mixed subtype. The mechanism of delirium development is not clear, but it is accepted that delirium is a result of the patient's underlying vulnerabilities or risk factors combined with an outside stressor such as infection or surgery.

Objective

To develop evidence-based recommendations for the prevention, diagnosis, and treatment of postoperative delirium.

Methods

Literature was searched from PubMed, CINAH, Google Scholar, and Cochrane databases that are published from 2010 to 2021 by formulating inclusion and exclusion criteria. Filtering was made depending on methodological quality, outcome, and data on population. Finally, 11 meta-analysis, 11 systematic reviews, 7 interventional studies, 11 observational studies, and recommendations of the previous clinical practice guideline developed by the American and European are included in this review.

Results

A total of 43 studies were considered in this evaluation. The development of this guideline was based on nine studies on risk stratification for postoperative delirium, eighteen studies on risk minimization and prevention for postoperative delirium, five studies on diagnosis for postoperative delirium, and eleven studies on treatments for postoperative delirium.

Conclusion

Postoperative delirium management can be categorized into risk assessment, risk minimization, early diagnosis, and treatment. Early diagnosis is critical to trigger focused and effective treatment. Non-pharmacological interventions are the first-line management for both hypoactive and hyperactive postoperative with considering contributory factors and underlying causes. Antipsychotics should only be used for hyperactive delirium individuals who try to harm themselves. Current evidence suggested that dexmedetomidine can be used as a treatment option for postoperative delirium.

Prevention of postoperative delirium through the avoidance of potentially inappropriate medications in a geriatric surgical patient

We demonstrate the utility of risk stratification for postoperative delirium in geriatric patients and show that postoperative delirium can be prevented in high-risk patients when potentially inappropriate medications (PIMs) (medications that are best avoided in older adults) are avoided. In this case, a 65-year-old woman underwent two debridement procedures with similar presurgical risk for postoperative delirium. There was no risk stratification or preoperative cognitive assessment in the first procedure, she received PIMs and developed postoperative delirium. In the second procedure, PIMs were intentionally avoided and postoperative delirium did not occur. This case supports recent recommendations from the European Society of Anaesthesiology, the American Society of Anesthesiologists and the American Geriatrics Society that providers assess a patient's cognitive function and delirium risk profile preoperatively to appropriately guide perioperative management.

Postoperative delirium in critically ill surgical patients: incidence, risk factors, and predictive scores

BACKGROUND

A common postoperative complication found among patients who are critically ill is delirium, which has a high mortality rate. A predictive model is needed to identify high-risk patients in order to apply strategies which will prevent and/or reduce adverse outcomes.

OBJECTIVES

To identify the incidence of, and the risk factors for, postoperative delirium (POD) in surgical intensive care unit (SICU) patients, and to determine predictive scores for the development of POD.

METHODS

This study enrolled adults aged over 18 years who had undergone an operation within the preceding week and who had been admitted to a SICU for a period that was expected to be longer than 24 h. The CAM - ICU score was used to determine the occurrence of delirium.

RESULTS

Of the 250 patients enrolled, delirium was found in 61 (24.4%). The independent risk factors for delirium that were identified by a multivariate analysis comprised age, diabetes mellitus, severity of disease (SOFA score), perioperative use of benzodiazepine, and mechanical ventilation. A predictive score (age + (5 × SOFA) + (15 × Benzodiazepine use) + (20 × DM) + (20 × mechanical ventilation) + (20 × modified IQCODE > 3.42)) was created. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.84 (95% CI: 0.786 to 0.897). The cut point of 125 demonstrated a sensitivity of 72.13% and a specificity of 80.95%, and the hospital mortality rate was significantly greater among the delirious than the non-delirious patients (25% vs. 6%, p < 0.01).

CONCLUSIONS

POD was experienced postoperatively by a quarter of the surgical patients who were critically ill. A risk score utilizing 6 variables was able to predict which patients would develop POD. The identification of high-risk patients following SICU admission can provide a basis for intervention strategies to improve outcomes.

TRIAL REGISTRATION

Thai Clinical Trials Registry TCTR20181204006 . Date registered on December 4, 2018. Retrospectively registered.

Assessment of Instruments for Measurement of Delirium Severity: A Systematic Review

Importance

Measurement of delirium severity has been recognized as highly important for tracking prognosis, monitoring response to treatment, and estimating burden of care for patients both during and after hospitalization. Rather than simply rating delirium as present or absent, the ability to quantify its severity would enable development and monitoring of more effective treatment approaches for the condition.

Objectives

To present a comprehensive review of delirium severity instruments, conduct a methodologic quality rating of the original validation study of the most commonly used instruments, and select a group of top-rated instruments.

Evidence Review

This systematic review was conducted using literature from Embase, PsycINFO, PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature, from January 1, 1974, through March 31, 2017, with the key words delirium, severity, tests, measures, and intensity. Inclusion criteria were original articles assessing delirium severity and using a delirium-specific severity instrument. Final listings of articles were supplemented with hand searches of reference listings to ensure completeness. At least 2 reviewers independently completed each step of the review process: article selection, data extraction, and methodologic quality assessment of relevant articles using a validated rating scale. All discrepancies between raters were resolved by consensus.

Findings

Of 9409 articles identified, 228 underwent full text review, and we identified 42 different instruments of delirium severity. Eleven of the 42 tools were multidomain, delirium-specific instruments providing a quantitative rating of delirium severity; these instruments underwent a methodologic quality review. Applying prespecified criteria related to frequency of use, methodologic quality, construct or predictive validity, and broad domain coverage, an expert panel used an iterative modified Delphi process to select 6 final high-quality instruments meeting these criteria: the Confusion Assessment Method-Severity Score, Confusional State Examination, Delirium-O-Meter, Delirium Observation Scale, Delirium Rating Scale, and Memorial Delirium Assessment Scale.

Conclusions and Relevance

The 6 instruments identified may enable accurate measurement of delirium severity to improve clinical care for patients with this condition. This work may stimulate increased usage and head-to-head comparison of these instruments.

Anesthesia in the Elderly Patient Undergoing Otolaryngology Head and Neck Surgery

Geriatric patients undergoing surgery have a whole set of specific physiologic changes, perioperative needs, and postoperative complications. This review presents an overview of the basic concepts and the evolving challenges pertaining to the care of geriatric patients undergoing otolaryngologic procedures from the perspective of the anesthesiologist.

The prevention of delirium in elderly with obstructive sleep apnea (PODESA) study: protocol for a multi-centre prospective randomized, controlled trial

Background

Delirium is a common problem that occurs in 5–50% of elderly individuals following surgery. Patients who develop delirium after surgery are at increased risk for serious complications. Recent studies suggest that patients with obstructive sleep apnea (OSA), a sleep disorder characterized by repeated episodes of complete or partial blockage of the upper airway – are at greater risk to develop delirium. OSA is more common in elderly individuals but is often undiagnosed. Identification and treatment of unrecognized OSA may reduce the incidence of postoperative delirium. However, few studies have investigated the effect of perioperative treatment of OSA to prevent postoperative delirium.

Methods

This multi-centre randomized controlled trial will enrol 634 elderly patients undergoing elective hip/knee replacement surgery. The study has been approved by the Research Ethics Boards of the three participating institutions. Patients will be screened with the STOP-Bang questionnaire. Those with a score of 3 or greater will have a portable home sleep study using the ApneaLink™ Air device. Patients identified to have OSA will be randomized to 1) Auto-titrating continuous positive airway pressure (APAP) applied during sleep for 72 h after surgery or until discharge if they are discharged before 72 h or 2) Control group – routine care, no APAP. All patients will be evaluated for delirium for 72 h after surgery or until discharge if they are discharged before 72 h. The primary outcome is the occurrence of delirium – assessed twice daily using the Confusion Assessment Method for 72 h or until discharge if the hospital stay is <72 h.

Discussion

Delirium is associated with increased morbidity and mortality, and higher healthcare costs. With the aging population, the incidence of postoperative delirium will likely increase as the number of elderly individuals undergoing surgery rises. The results of our study will be published in a peer-reviewed journal and presented at local and international medical conferences. Our study findings may lead to improved surgical outcomes, enhanced patient safety and reduced healthcare costs.

Trial registration

This study was retrospectively registered at clinicaltrials.gov NCT02954224 on November 3, 2016.

Prevention and Management of Postoperative Delirium in Elderly Patients Following Elective Spinal Surgery

STUDY DESIGN

This study is a systematic review.

OBJECTIVE

Propose an evidence-based algorithm for prevention, diagnosis, and management of postoperative delirium in geriatric patients undergoing elective spine surgery.

SUMMARY OF BACKGROUND DATA

Delirium is associated with longer stays after elective surgery, increased risk of readmission, and $6.9 billion annually in medical costs. Early diagnosis and treatment of delirium can reduce length of stay (LOS), in-hospital morbidity, and health care costs. After spinal surgery, postoperative delirium increases average LOS to >7 days and is diagnosed in 12.5%-24.3% of geriatric patients. Currently, studies for management of postoperative delirium after elective spinal procedures are not available.

METHODS

A literature review was performed for observational studies, randomized controlled trials, and systematic reviews between 1990 and 2015.

RESULTS

Risk factors for delirium after elective spinal surgery include age, functional impairment, preexisting dementia, general anesthesia, surgical duration >3 hours, intraoperative hypercapnia and hypotension, greater blood loss, low hematocrit and albumin, preoperative affective dysfunction, and postoperative sleep disorders. Postoperatively, decreasing the use of methylprednisolone and promoting movement with an appropriate orthosis can reduce delirium incidence (P=0.0091). Polypharmacy is an independent risk factor for delirium (P=0.01) and decreasing use of delirium-inducing medications may reduce incidence. The delirium observation screening scale diagnoses and monitors delirium and is rated by nurses as easier to use than the NEECHAM Confusion Scale (P<0.003). Haloperidol is used widely to treat postoperative delirium. Randomized controlled trials show that adding quetiapine results in delirium resolution an average of 3.5 days faster than haloperidol alone (P=0.001) and decreases agitation and LOS (P=0.02; P=0.05).

CONCLUSIONS

An evidence-based algorithm is proposed to prevent, diagnose, and manage postoperative delirium that can be used clinically for geriatric patients undergoing elective spine surgery. Prevention and diagnosis involve efforts from the anesthesiologist and postoperative clinical care team. Treatment may include a therapeutic regimen of low-dose neuroleptic medications as needed.

LEVEL OF EVIDENCE

Level II.

Postoperative Delirium in the Geriatric Patient

Postoperative delirium, a common complication in older surgical patients, is independently associated with increased morbidity and mortality. Patients older than 65 years receive greater than one-third of the more than 40 million anesthetics delivered yearly in the United States. This number is expected to increase with the aging of the population. Thus, it is increasingly important that perioperative clinicians who care for geriatric patients have an understanding of the complex syndrome of postoperative delirium.