The temporal relationship between early postoperative delirium and postoperative cognitive dysfunction in older patients: a prospective cohort study

Assessment and report of individual symptoms in studies of delirium in postoperative populations: a systematic review

OBJECTIVES

Delirium is most often reported as present or absent. Patients with symptoms falling short of the diagnostic criteria for delirium fall into 'no delirium' or 'control' groups. This binary classification neglects individual symptoms and may be hindering identification of the pathophysiology underlying delirium. This systematic review investigates which individual symptoms of delirium are reported by studies of postoperative delirium in adults.

METHODS

Medline, EMBASE and Web of Science databases were searched on 03 June 2021 and 06 April 2023. Two reviewers independently examined titles and abstracts. Each paper was screened in duplicate and conflicting decisions settled by consensus discussion. Data were extracted, qualitatively synthesised and narratively reported. All included studies were quality assessed.

RESULTS

These searches yielded 4,367 results. After title and abstract screening, 694 full-text studies were reviewed, and 62 deemed eligible for inclusion. This review details 11,377 patients including 2,049 patients with delirium. In total, 78 differently described delirium symptoms were reported. The most reported symptoms were inattention (N = 29), disorientation (N = 27), psychomotor agitation/retardation (N = 22), hallucination (N = 22) and memory impairment (N = 18). Notably, psychomotor agitation and hallucinations are not listed in the current Diagnostic and Statistical Manual for Mental Disorders-5-Text Revision delirium definition.

CONCLUSIONS

The 78 symptoms reported in this systematic review cover domains of attention, awareness, disorientation and other cognitive changes. There is a lack of standardisation of terms, and many recorded symptoms are synonyms of each other. This systematic review provides a library of individual delirium symptoms, which may be used to inform future reporting.

Association between postoperative delirium and adverse outcomes in older surgical patients: A systematic review and meta-analysis

STUDY OBJECTIVE

To assess the incidence of postoperative delirium and its outcomes in older non-cardiac surgical patients.

DESIGN

A systematic review and meta-analysis with multiple databases searched from inception to February 22, 2022.

SETTING

Postoperative assessments.

PATIENTS

Non-cardiac and non-neurological surgical patients aged ≥60 years with and without postoperative delirium. Included studies must report ≥1 postoperative outcome. Studies with a small sample size (N < 100 subjects) were excluded.

MEASUREMENTS

Outcomes comprised the pooled incidence of postoperative delirium and its postoperative outcomes, including mortality, complications, unplanned intensive care unit admissions, length of stay, and non-home discharge. For dichotomous and continuous outcomes, OR and difference in means were computed, respectively, with a 95% CI.

MAIN RESULTS

Fifty-four studies (20,988 patients, 31 elective studies, 23 emergency studies) were included. The pooled incidence of postoperative delirium was 19% (95% CI: 16%, 23%) after elective surgery and 32% (95% CI: 25%, 39%) after emergency surgery. In elective surgery, postoperative delirium was associated with increased mortality at 1-month (OR: 6.60; 95% CI: 1.58, 27.66), 6-month (OR: 5.69; 95% CI: 2.33, 13.88), and 1-year (OR: 2.87; 95% CI: 1.63, 5.06). The odds of postoperative complications, unplanned intensive care unit admissions, prolonged length of hospital stay, and non-home discharge were also higher in delirium cases. In emergency surgery, patients with postoperative delirium had greater odds of mortality at 1-month (OR: 3.56; 95% CI: 1.77, 7.15), 6-month (OR: 2.60; 95% CI: 1.88, 3.61), and 1-year (OR: 2.30; 95% CI: 1.77, 3.00).

CONCLUSIONS

Postoperative delirium was associated with higher odds of mortality, postoperative complications, unplanned intensive care unit admissions, length of hospital stay, and non-home discharge. Prevention and perioperative management of delirium may optimize surgical outcomes.

Postoperative outcomes in older surgical patients with preoperative cognitive impairment: A systematic review and meta-analysis

STUDY OBJECTIVE

To determine the effect of cognitive impairment (CI) and dementia on adverse outcomes in older surgical patients.

DESIGN

A systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs). Various databases were searched from their inception dates to March 8, 2021.

SETTING

Preoperative assessment.

PATIENTS

Older patients (≥ 60 years) undergoing non-cardiac surgery.

MEASUREMENTS

Outcomes included postoperative delirium, mortality, discharge to assisted care, 30-day readmissions, postoperative complications, and length of hospital stay. Effect sizes were calculated as Odds Ratio (OR) and Mean Difference (MD) based on random effect model analysis. The quality of included studies was assessed using the Cochrane Risk Bias Tool for RCTs and Newcastle-Ottawa Scale for observational cohort studies.

RESULTS

Fifty-three studies (196,491 patients) were included. Preoperative CI was associated with a significant risk of delirium in older patients after non-cardiac surgery (25.1% vs. 10.3%; OR: 3.84; 95%CI: 2.35, 6.26; I²: 76%; p < 0.00001). Cognitive impairment (26.2% vs. 13.2%; OR: 2.28; 95%CI: 1.39, 3.74; I²: 73%; p = 0.001) and dementia (41.6% vs. 25.5%; OR: 1.96; 95%CI: 1.34, 2.88; I²: 99%; p = 0.0006) significantly increased risk for 1-year mortality. In patients with CI, there was an increased risk of discharge to assisted care (44.7% vs. 38.3%; OR 1.74; 95%CI: 1.05, 2.89, p = 0.03), 30-day readmissions (14.3% vs. 10.8%; OR: 1.36; 95%CI: 1.00, 1.84, p = 0.05), and postoperative complications (40.7% vs. 18.8%; OR: 1.85; 95%CI: 1.37, 2.49; p < 0.0001).

CONCLUSIONS

Preoperative CI in older surgical patients significantly increases risk of delirium, 1-year mortality, discharge to assisted care, 30-day readmission, and postoperative complications. Dementia increases the risk of 1-year mortality. Cognitive screening in the preoperative assessment for older surgical patients may be helpful for risk stratification so that appropriate management can be implemented to mitigate adverse postoperative outcomes.

Penehyclidine Hydrochloride Premedication Is Not Associated with Increased Incidence of Post-Operative Cognitive Dysfunction or Delirium:A Systemic Review and Meta-Analysis

Objective Post-operative cognitive dysfunction (POCD) and post-operative delirium (POD) are two common post-operative cerebral complications. The current meta-analysis was to systematically review the effects of penehyclidine hydrochloride (PHC) on POCD and POD in surgical patients.Methods Electronic databases were searched to identify all randomized controlled trials comparing PHC with atropine/scopolamine/placebo on POCD and POD in surgical patients. Primary outcomes of interest included the incidences of POCD and POD; the secondary outcomes of interest included peri-operative mini-mental state examination (MMSE) scores. Two authors independently extracted peri-operative data, including patients' baseline characteristics, surgical variables, and outcome data. For dichotomous data (POCD and POD occurrence), treatment effects were calculated as odds ratio (OR) and 95% confidential interval (CI). Each outcome was tested for heterogeneity, and randomized-effects or fixed-effects model was used in the presence or absence of significant heterogeneity. For continuous variables (MMSE scores), treatment effects were calculated as weighted mean difference (WMD) and 95% CI. Statistical significance was defined as P<0.05.Results Our search yielded 33 studies including 4017 patients. Meta-analysis showed that, the incidence of POCD in PHC group was comparable to that in saline group (OR=0.97; 95% CI: 0.58-1.64; P=0.92), scopolamine group (OR=0.78; 95% CI: 0.48-1.27; P=0.32) and atropine group (OR=1.20; 95% CI: 0.86-1.67; P=0.29). The incidence of POD in PHC group was comparable to that in saline group (OR=1.53; 95% CI: 0.81-2.90; P=0.19) and scopolamine group (OR=0.53; 95% CI: 0.06-4.56; P=0.56), but higher than that in atropine group (OR=4.49; 95% CI: 1.34-15.01; P=0.01).Conclusions PHC premedication was not associated with increased incidences of POCD or POD as compared to either scopolamine or placebo.

Neurocognitive Function after Cardiac Surgery: From Phenotypes to Mechanisms

For half a century, it has been known that some patients experience neurocognitive dysfunction after cardiac surgery; however, defining its incidence, course, and causes remains challenging and controversial. Various terms have been used to describe neurocognitive dysfunction at different times after cardiac surgery, ranging from "postoperative delirium" to "postoperative cognitive dysfunction or decline." Delirium is a clinical diagnosis included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Postoperative cognitive dysfunction is not included in the DSM-5 and has been heterogeneously defined, though a recent international nomenclature effort has proposed standardized definitions for it. Here, the authors discuss pathophysiologic mechanisms that may underlie these complications, review the literature on methods to prevent them, and discuss novel approaches to understand their etiology that may lead to novel treatment strategies. Future studies should measure both delirium and postoperative cognitive dysfunction to help clarify the relationship between these important postoperative complications.

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.

Perioperative cerebrospinal fluid and plasma inflammatory markers after orthopedic surgery

Background

Postoperative delirium is prevalent in older patients and associated with worse outcomes. Recent data in animal studies demonstrate increases in inflammatory markers in plasma and cerebrospinal fluid (CSF) even after aseptic surgery, suggesting that inflammation of the central nervous system may be part of the pathogenesis of postoperative cognitive changes. We investigated the hypothesis that neuroinflammation was an important cause for postoperative delirium and cognitive dysfunction after major non-cardiac surgery.

Methods

After Institutional Review Board approval and informed consent, we recruited patients undergoing major knee surgery who received spinal anesthesia and femoral nerve block with intravenous sedation. All patients had an indwelling spinal catheter placed at the time of spinal anesthesia that was left in place for up to 24 h. Plasma and CSF samples were collected preoperatively and at 3, 6, and 18 h postoperatively. Cytokine levels were measured using ELISA and Luminex. Postoperative delirium was determined using the confusion assessment method, and cognitive dysfunction was measured using validated cognitive tests (word list, verbal fluency test, digit symbol test).

Results

Ten patients with complete datasets were included. One patient developed postoperative delirium, and six patients developed postoperative cognitive dysfunction. Postoperatively, at different time points, statistically significant changes compared to baseline were present in IL-5, IL-6, I-8, IL-10, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, IL-6/IL-10, and receptor for advanced glycation end products in plasma and in IFN-γ, IL-6, IL-8, IL-10, MCP-1, MIP-1α, MIP-1β, IL-8/IL-10, and TNF-α in CSF.

Conclusions

Substantial pro- and anti-inflammatory activity in the central neural system after surgery was found. If confirmed by larger studies, persistent changes in cytokine levels may serve as biomarkers for novel clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0681-9) contains supplementary material, which is available to authorized users.

Effects of propofol versus sevoflurane on cerebral oxygenation and cognitive outcome in patients with impaired cerebral oxygenation

Background

Postoperative neurocognitive dysfunction induced by anesthetics, particularly in elderly patients with impaired oxygenation, is a common complication of surgery and is eliciting increased interest in clinical practice. To investigate the effects of anesthetics on neurocognition, we compared the effects of propofol versus sevoflurane on cerebral oxygenation and cognitive outcome in patients with impaired cerebral oxygenation undergoing general anesthesia.

Methods

Sixty-three patients with impaired cerebral oxygenation (jugular venous bulb oxygen saturation [SjvO₂] <50%) or cerebral blood flow/cerebral metabolic rate of oxygen ([CBF/CMRO₂] ≤15%) undergoing elective abdominal surgery were randomly allocated into propofol group (group P) or sevoflurane group (group S). The clinical parameters and jugular venous bulb blood gas analysis were monitored throughout the surgical procedure. Cognitive function was assessed with the mini-mental state examination and Montreal Cognitive Assessment at day 1 and day 7 following surgery. S100β protein in plasma was measured using enzyme-linked immunosorbent assay.

Results

The SjvO₂ increased during anesthesia induction and surgery when compared to baseline but had no significant difference between group P and group S. When compared to baseline, the CBF/CMRO₂ was increased only at the end of surgery and extubation in group P; however, the CBF/CMRO₂ in group S was increased during anesthesia induction at 1 hour, 2 hours, end of surgery, and extubation. Furthermore, the CBF/CMRO₂ in group S was significantly higher than that in group P during anesthesia induction at 1 hour, 2 hours, and end of surgery. S100β protein did not significantly change at extubation and 1 day after surgery in both groups when compared to baseline. There was no significant difference in mini-mental state examination and Montreal Cognitive Assessment scores between group P and group S at all time points.

Conclusion

Sevoflurane showed similar effects in postoperative neurocognitive function as propofol but could improve cerebral oxygenation in patients with impaired cerebral oxygenation.

Comprehensive Geriatric Assessment is a useful predictive tool for postoperative delirium after gastrointestinal surgery in old-old adults

AIM

To determine whether carrying out the Comprehensive Geriatric Assessment before operations would be useful for predicting complications, particularly postoperative delirium (POD), in old-old patients.

METHODS

A total of 517 patients aged 75 years and older, who underwent radical surgery for gastrointestinal cancer at Osaka University Hospital, were recruited for this observational study. The Comprehensive Geriatric Assessment components and assessment of performance status were carried out before surgery, and a record of postoperative complications including POD was made prospectively until discharge from hospital. The following morphological and clinical measurements were also obtained from the medical records: age, sex, disease type, previous history, comorbid lifestyle-related diseases, POD, postoperative complications, operative method, duration of operation, hemorrhage volume, blood transfusion volume, method of anesthesia, body mass index and blood tests.

RESULTS

POD appeared in 24.0% of the 517 patients who underwent surgery. Barthel Index, Mini-Mental State Examination, instrumental activities of daily living and Geriatric Depression Scale results were associated with the incidence of POD, and the Barthel Index, Mini-Mental State Examination and Instrumental Activities of Daily Living results were extracted as independent factors associated with the development of POD after adjusting for traditional risk factors for postoperative complications and performance status.

CONCLUSIONS

The Comprehensive Geriatric Assessment before gastrointestinal surgery can be a useful tool for predicting the development of POD in old-old patients. Geriatr Gerontol Int 2016; 16: 1036-1042.

Using Human Factors and Systems Engineering to Evaluate Readmission after Complex Surgery

BACKGROUND

Our objective was to use a human factors and systems engineering approach to understand contributors to surgical readmissions from a patient and provider perspective. Previous studies on readmission have neglected the patient perspective. To address this gap and to better inform intervention design, we evaluated how transitions of care relate to and influence readmission from the patient and clinician perspective using the Systems Engineering Initiative for Patient Safety (SEIPS) model.

STUDY DESIGN

Patients readmitted within 30 days of discharge after complex abdominal surgery were interviewed. A focus group of inpatient clinician providers was conducted. Questions were guided by the SEIPS framework and content was analyzed. Data were collected concurrently from the medical record for a mixed-methods approach.

RESULTS

Readmission occurred a median of 8 days (range 1 to 25 days) after discharge. All patients had follow-up scheduled with their surgeon, but readmission occurred before this in 72% of patients. Primary readmission diagnoses included infection, gastrointestinal complications, and dehydration. Patients (n = 18) and clinician providers (n = 6) identified a number of factors during the transition of care that may have contributed to readmission, including poor patient and caregiver understanding; inadequate discharge preparation for home care; insufficient educational process and materials, negatively affected by electronic health record design; and inadequate care team communication.

CONCLUSIONS

This is the first study to use a human factors and systems engineering approach to evaluate the impact of the quality of the transition of care and its influence on readmission from the patient and clinician perspective. Important targets for future interventions include enhancing the discharge process, improving education materials, and increasing care team coordination, with the overarching theme that improved patient and caregiver understanding and engagement are essential to decrease readmission and postdischarge health care use.

Sensitivity and specificity of the animal fluency test for predicting postoperative delirium

BACKGROUND

Preoperative cognitive impairment is a major risk factor for postoperative delirium. We therefore investigated the prognostic significance and feasibility of administering a brief cognitive screen before surgery.

METHODS

Patients > 65 yr of age undergoing hip, knee, or spine surgery were enrolled. A 60-sec cognitive screen, the animal fluency test (AFT), was administered preoperatively. Postoperative delirium was measured using a chart-based tool previously validated using criteria from the Confusion Assessment Method.

RESULTS

Of the 362 patients satisfying the inclusion/exclusion criteria, 199 (55%) underwent the AFT. Among them, 57 patients (29%) had an AFT score < 15, and 38 patients (19%, 95% confidence interval [CI]: 14 to 25%) developed postoperative delirium as measured by chart review. Patients with scores of < 15 were more likely to develop postoperative delirium than those who scored ≥ 15 (54% vs 5%, P < 0.01). A multiple logistic regression, with postoperative delirium as the dependent variable, identified an AFT score of < 15 (odds ratio 20.1, 95% CI: 7.9 to 51.4) and high American Society of Anesthesiologists classification (odds ratio 3.5, 95% CI: 1.3 to 9.2) as independent predictors.

CONCLUSIONS

The AFT is a potentially useful brief cognitive screen for identifying patients at risk of developing postoperative delirium. Limited participation by eligible participants in this study, however, raises questions about how useful and feasible systematic administration of the test is. Large studies using prospective measurement of postoperative delirium are indicated to validate our results.