Assessment of the incidence and risk factors of postoperative delirium in neurosurgery: A prospective observational study

BackgroundIntravenous patient-controlled analgesia (IVPCA) is a common method of relieving pain which is a risk factor of postoperative delirium (POD). However, research concerning POD in IVPCA patients is limited.ObjectiveWe aimed to determine the incidence, risk factors, and phenomenological characteristics of POD in patients receiving IVPCA.MethodsA prospective, cohort study was conducted in post-general anesthesia IVPCA patients aged ≥60 years. POD was measured by the Nursing Delirium Screening Scale (NuDESC; 0–10). Delirium, pain severity at rest and/or on movement, and side effects of IVPCA during 3 postoperative days were examined twice-daily by the acute pain service team. Pain severity is measured by an 11-point verbal numerical rating scale (11-point VNRS) (0–10). An 11-point VNRS >3 was considered inadequate pain relief. If POD (detected by NuDESC ≥1) is suspected, consulting a neurologist or a psychiatrist to confirm suspected POD is required.ResultsIn total, 1,608 patients were included. The incidence rate of POD was 2.2%. Age ≥70 years and American Society of Anesthesiologists physical status >III were the risk factors of POD in IVPCA patients. Approximately three-quarters of all POD cases occurred within the first 2 postoperative days. For pain at rest, patients with inadequate pain relief had significantly greater rates of POD than patients with adequate pain relief (day 1, 8.4% vs 1.5%, P<0.001; day 2, 9.6% vs 2.0%, P=0.028; day 3, 4.1% vs 2.1%, P=0.412). However, the incidence of POD was not associated with movement-evoked pain relief. Most (79.9%) POD cases in IVPCA patients showed either one or two symptoms. The symptoms of POD were ranked from high to low as disorientation (65.7%), illusions/hallucinations (37.1%), inappropriate communication (31.4%), inappropriate behavior (25.7%), and psychomotor retardation (14.2%).ConclusionThe incidence rate of POD in IVPCA patients was low. Further research is warranted concerning POD and IVPCA pain management.

Editor, We thank Wan et al.1 for their interest in our cohort study on postoperative delirium in patients admitted to the ICU after intracranial surgery2 and appreciate the opportunity to respond. For the diagnosis of postoperative delirium, the Diagnostic and Statistical Manual of Mental Disorders (DSM), fifth edition nomenclature is recommended.3 However, to assist nonpsychiatrically trained clinicians to identify delirium quickly and accurately, several DSM-based instruments have been developed, including the Confusion Assessment Method (CAM)4 and CAM for the ICU (CAM-ICU).5 We used the CAM-ICU for several reasons. All enrolled patients were transferred to the ICU after craniotomy, and all assessments of postoperative delirium were performed in the ICU on postoperative day 1. In our cohort, 2.2% of the patients (18/800, Table 4) were mechanically ventilated when assessing delirium on postoperative day 1, but 27.5% of the patients (220/800, unpublished data used in immobilising factor score) were intubated. As the most widely recognised screening scale of postoperative delirium in the ICU, CAM-ICU is recommended by the American Society of Critical Care Medicine as a delirium assessment tool in adult patients in the ICU6 and is suggested by the European Society of Anaesthesiology as a postoperative delirium screening tool in postoperative patients.7 Therefore, in many cohort and controlled studies, CAM-ICU has been employed as an effective tool for the assessment of postoperative delirium in the ICU.8–11 We agree with Wan et al. that in our study, the incidence of postoperative delirium may have been confounded by the assessment tool and the time window for the monitoring. As we discussed in our article, although previous studies reported that the incidence of postoperative delirium decreased in a time-dependent manner, delirium may occur from postoperative day 4 to day 7 (but less than 5%).11,12 Furthermore, it has been reported that, compared with the Diagnostic and Statistical Manual of the American Psychiatric Association, the sensitivity of CAM-ICU to detect delirium is relatively low in the recovery room setting.7 All these factors may have caused an underestimation of the incidence of postoperative delirium in our cohort. Therefore, our results still indicate the importance of postoperative delirium in the population we studied. Regarding the analysis of risk factors for postoperative delirium, we did follow the overall strategy univariate analyses first (Tables 1 to 4), followed by multivariate analyses (Table 5). Wan et al. may have some misunderstanding of univariate analysis. The main purpose of the univariate analysis is to identify candidate risk factors or covariates, rather than to estimate the size of the effect [the odds ratio (OR) and its 95% confidence interval (CI) were calculated in our study]. Therefore, we can either examine the distribution of variables between the groups or use one independent variable at a time to fit a regression model to identify potential risk factors. We prefer the former because this form of data is more informative with the summary and report of descriptive statistics and the P value in statistical tests. As for the estimation of the effect size, we reported the original and adjusted ORs and 95% CIs of the risk factors in the multivariate logistic regression model in Table 5. These factors are more valuable for preventing postoperative delirium. For more detailed information about our statistical strategy, please refer to other reports.13,14 We used backward stepwise variable selection in multivariate logistic regression because this method can obtain a performance similar to the Bootstrap method, but it is easy to perform.15 We agree with Wan et al. that a number of demographic and peri-operative factors may lead to adverse postoperative outcomes. That is why we did not take the causal relationship between postoperative delirium and adverse consequences as the end point of the study. As we pointed out in the article,2 our data show the potential association between postoperative delirium and adverse outcomes. Considering the relatively high incidence of postoperative delirium and the identified risk factors, our study indicates a comprehensive strategy to prevent postoperative delirium after intracranial surgery. In summary, one study cannot solve all problems. We thank Wan et al. for their suggestions for identifying and investigating safe and effective interventions to reduce the incidence, duration and severity of postoperative delirium, which might provide the readers with more information. With the help of all the readers, we will keep working on postoperative delirium issues to figure it out.

Postoperative delirium has the potential to impact individuals of all age groups, with a significant emphasis on the elderly population. Its presence leads to an increase in surgical morbidity and mortality rates, as well as a notable prolongation of hospital stays. However, there is a lack of research regarding the prevalence, risk factors, and implications of postoperative delirium in developing nations like Ethiopia, which affects both patients and healthcare institutions. An observational study was conducted at hospitals in the South Gondar Zone to diagnose postoperative delirium in the Post-Anesthesia Care Unit (PACU) using the Nursing Delirium Screening Scale. Both bivariable and multivariable logistic regression techniques were employed to analyze the association between independent factors and postoperative delirium. The strength of the association was indicated by the odds ratio with a 95% confidence interval (CI). Any p-values below 0.05 were considered statistically significant. The incidence of postoperative delirium was determined to be 41%. In the multivariate logistic regression analysis, several factors were identified as significantly associated with postoperative delirium. These factors include an age of 75 or older (AOR, 11.24; 95% CI, 4.74–26.65), ASA-PS IV (AOR, 3.25; 95% CI, 1.81–5.85), severe functional impairment of activities of daily living (AOR, 3.29; 95% CI, 1.06–10.20), premedication with benzodiazepine (AOR, 4.61; 95% CI, 2.48–8.57), intraoperative estimated blood loss exceeding 1000 ml (AOR, 2.74; 95% CI, 1.50–4.98), and intraoperative ketamine use (AOR, 3.84; 95% CI, 2.21–6.68). Additionally, postoperative delirium was found to significantly prolong the duration of stay in the post-anesthesia care unit (PACU) and the length of hospital stay (p-value < 0.05). Patients aged 75 or older, ASA-PS IV, experiencing severe functional impairment of ADL, patients premedicated with benzodiazepine, patients with intraoperative estimated blood loss exceeding 1000 ml, and intraoperative ketamine use were identified as risk factors for post-operative delirium.

To evaluate the incidence and risk factors of postoperative delirium in patients post permanent pacemaker implantation. Patients underwent permanent pacemaker implantation in our department from September 2013 to February 2015 were included in this study. Delirium was measured by the confusion assessment method on the first three postoperative days. All the patients were divided into the postoperative delirium group and the non-delirium control group according to whether new onset delirium was diagnosed. Risk factors significantly associated with postoperative delirium detected by univariate analysis were entered into multivariable analysis to define the independent predictors of postoperative delirium. A total of 225 patients were enrolled in this study. The incidence of postoperative delirium was 5.3%. Patients developing postoperative delirium were older ((83±5) years vs. (74±11) years, P=0.002), had a significantly higher incidence of blood pressure fluctuations (58.3% (7/12) vs. 4.7% (10/213), P<0.001), hyponatremia (25.0% (3/12) vs. 5.2% (11/213), P=0.030) and had higher systolic blood pressure ((157±35) mmHg vs. (136±22)mmHg, 1 mmHg=0.133 kPa, P=0.007). However, patients developing postoperative delirium had lower preoperative average heart rate ( (47±18)bpm vs. (58±15)bpm, P=0.007). Multiple regression analysis showed that advanced age (OR= 2.984, 95% CI: 1.226-7.624, P=0.016) and blood pressure fluctuations (OR=27.393, 95% CI: 6.735-111.417, P<0.001) are the independent risk factors for pacemaker patients with postoperative delirium. Advanced age and blood pressure fluctuations are independent risk factors of postoperative delirium in patients post permanent pacemaker implantation.

In Response.

Postoperative delirium (POD) commonly occurs after major abdominal surgery and is associated with increased morbidity and mortality. There have been many studies on the relationship between POD and various surgeries, but research on POD after pancreatic cancer surgery is limited. The aim of this study was to identify the incidence and risk factors of POD after pancreatic cancer surgery. The subjects of this retrospective analysis were 196 patients who were transferred for postoperative care after pancreatic cancer surgery, to a 12-bed critical care medicine ward at Shandong Provincial Hospital, affiliated with Shandong First Medical University, between January 2015 and December 2019. The patients were divided according to whether they suffered POD into a delirium group and a non-delirium group. Delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit and two independent medical practitioners analyzed all the data. Univariate and multiple logistic regression analyses were performed. The overall delirium incidence was 20.41%, which increased to 29.03% for patients aged ≥ 70years. POD was associated with age, smoking, the American Society of Anesthesiologists classification, the Acute Physiology and Chronic Health Evaluation II score, and the TNM stage of the cancer. The variables concerning sex, drinking, hypertension, a history of cerebral disease, surgery type, operation time, amount of bleeding, and the intraoperative use of dexmedetomidine did not differ significantly between the two groups. There was no significant difference in the length of ICU stay, with the exclusion of long-term stay for complications, between the groups, but POD tended to prolong the postoperative hospital stay and increase the risk of mortality. There was also a gradual decline in the incidence of POD between 2015 and 2019, especially from 2015 to 2018, after preventive measures were implemented. POD is related to many risk factors and worthy of attention. Appropriate management can reduce its incidence or at least shorten its duration.

Incidence and Risk Factors of Postoperative Delirium in Lumbar Spinal Fusion Patients: A National Database Analysis

The incidence of postoperative delirium is reported to range from 9 to 87%; however, no report has focused on cases of postoperative delirium in gastric cancer surgery alone. Therefore, we investigated the incidence of and risk factors for postoperative delirium after gastrectomy in patients with gastric cancer. A total of 1037 patients who underwent surgery were included in the study. Patients were divided into two groups-those with (delirium group) or without (non-delirium group) postoperative delirium-and their backgrounds were compared. The short-term outcomes and the overall survival were also investigated. Postoperative delirium was observed in 47 of 1037 patients (4.5%). A multivariate analysis revealed that male gender, age ≥ 75years, a history of cerebrovascular disease, and the habitual use of sleeping pills were independent predictive factors for postoperative delirium. The postoperative hospital stay was significantly longer in the postoperative delirium group than in the non-delirium group. Postoperative delirium was significantly associated with postoperative complications. The 3-year overall survival was 74.3% in the delirium group and 85.5% in the non-delirium group (log-rank p = 0.006). A multivariate analysis revealed that postoperative delirium was an independent prognostic factor, along with the age and cancer stage. The incidence of postoperative delirium was 4.5% in gastric cancer patients. Male gender, age ≥ 75years, a history of cerebrovascular disease, and the habitual use of narcoleptic agents were risk factors for postoperative delirium after gastrectomy in gastric cancer patients. Postoperative delirium was strongly associated with other postoperative complications and a poor survival after surgery.

Delirium is an acute cognitive change characterized by behavioral and psychological features, such as visual and auditory hallucinations, sleep disturbances, and emotional confusion. It can lead to extended hospital stays, increased mortality risk, and higher nursing costs. In postoperative hip fracture patients, delirium results in a higher complication rate, poorer functional recovery, increased readmission rates, repeat surgeries, and elevated mortality. Despite these serious consequences, the literature provides limited information on the incidence of postoperative delirium following hip fracture surgeries in Asians. Additionally, there is a lack of long-term, comprehensive nationwide population-based studies, highlighting an important area for future research. This study aims to understand the incidence and risk factors of postoperative delirium in hip fracture patients using representative population data. We conducted a retrospective cohort study using the Taiwan National Health Insurance Research Database (NHIRD) from 2009 to 2020. The cohort consisted of 118,682 patients aged 65years or older who were diagnosed with hip fractures. The delirium incidence was observed per 1000 person-years. The Cox proportional hazards model was used to investigate the incidence of delirium among hip fracture patients. The incidence of the first episode of delirium after hip surgery in the elderly was 1.87 events per 1000 PYs. Factors associated with delirium included being female (adjusted hazard ratio [aHR]: 0.59; 95% confidence interval [CI]: 0.53-0.64), age ≥95years (aHR: 3.52; 95% CI: 2.74-4.51), comorbid dementia (aHR: 2.63; 95% CI: 2.38-2.92), and ICU stay 2-3days (aHR: 2.85; 95% CI: 1.28-6.37). The occurrence of delirium was significantly associated with an ICU stay of ≥4days, dementia, as well as 30-day, 90-day, and 1-year mortality (p<0.001). This study highlights the relatively low incidence of postoperative delirium in elderly hip fracture patients in Taiwan. Key risk factors identified include advanced age, female gender, comorbid dementia, and prolonged ICU stays. These findings underscore the need for targeted prevention and early intervention strategies to improve patient outcomes.

Delirium after transcatheter aortic valve implantation (TAVI) should be prevented because it is associated with worse patient outcomes. Perioperative administration of benzodiazepines is a risk factor for postoperative delirium; however, the association between remimazolam, a newer ultrashort-acting benzodiazepine for general anesthesia, and postoperative delirium remains unclear. This study aimed to evaluate whether remimazolam administration during TAVI under general anesthesia affected the incidence of postoperative delirium. This single-center retrospective study recruited all adult patients who underwent transfemoral TAVI (TF-TAVI) under general anesthesia between March 2020 and May 2022. Patients were divided into the remimazolam (R) and propofol (P) groups according to the sedative used for anesthesia. In the R group, all patients received flumazenil after surgery. The primary endpoint was the incidence of delirium within 3days after surgery. Factors associated with delirium after TF-TAVI were examined by multiple logistic regression analysis. Ninety-eight patients were included in the final analysis (R group, n = 40; P group, n = 58). The incidence of postoperative delirium was significantly lower in the R group than in the P group (8% vs. 26%, p = 0.032). Multiple logistic regression analysis revealed that remimazolam (odds ratio 0.17, 95% CI 0.04-0.80, p = 0.024) was independently associated with the incidence of postoperative delirium, even after adjustment for age, sex, preoperative cognitive function, history of stroke, and TF-TAVI approach. Remimazolam may benefit TF-TAVI in terms of postoperative delirium; however, its usefulness must be further evaluated in extensive prospective studies.

Retrospective clinical review and prospective report of postoperative delirium after cervical spine surgeries. To investigate factors contributing to the development of delirium after cervical surgery and see whether amended therapeutic protocols could improve or alter postoperative outcomes. Important consequences of postoperative delirium for the orthopedic patients include impaired recovery and increased morbidity and mortality. Although its risk factors have been reported in orthopedic surgery, there are a very few reports regarding postoperative delirium in spine surgery. Eighty-one cervical myelopathy patients were retrospectively examined about the incidence of postoperative delirium and the risk factors. Similarly, 41 patients who received postoperative care under modified protocols were prospectively examined. Postoperative delirium occurred more commonly in patients over 70 years and those with hearing impairment. Patients who received high-dose methylprednisolone (>1000 mg) demonstrated an increased incidence of postoperative delirium. Under modified protocol, we reduced the usage of methylprednisolone and encouraged free body movement with cervical orthosis immediately after surgery. The incidence of postoperative delirium was significantly lower under the modified protocol. Early commencement of mobilization after cervical spine surgery would be crucial to the prevention of postoperative delirium in the elderly.

Delirium is associated with longer hospital stays and increased medical costs and mortality. This study explored the risk factors for postoperative delirium in gastroenterological surgery and investigated the association between qualitative changes in risk factors and the incidence of postoperative delirium. A total of 418 patients > 18years old who underwent gastroenterological surgery at our department between April 2018 and September 2019 were included. Risk factors were identified by comparing patients with and without postoperative delirium. Continuous variables were evaluated graphically using cubic spline curves. A logistic regression analysis was performed to assess independent risk factors. The incidence of postoperative delirium was 6.9%. The cubic spline curve showed that the incidence of postoperative delirium began to increase at 50years old and increased sharply at 70years old. A multiple logistic regression analysis of patients > 50years old identified 5 risk factors: age ≥ 70years, preoperative serum albumin ≤ 3.8g/dL, psychosis, sedative-hypnotics, and intensive-care unit admission. The risk of postoperative delirium increases progressively at 50years old and sharply at 70years old. Advanced age, preoperative hypoalbuminemia, psychosis, sedative-hypnotics, and intensive-care unit admission are risk factors for postoperative delirium in patients > 50years old undergoing gastroenterological surgery.

BackgroundPostoperative delirium is a common complication in elderly patients who have undergone hip fracture surgery. Since postoperative delirium is associated with poor outcomes and the treatment is very complicated, identifying the patients at high risk for delirium and providing more attentive care to prevent postoperative delirium is essential. In this study, we aimed to assess the association of an elevated C-reactive protein (CRP)/albumin ratio with the increased incidence of postoperative delirium in elderly people who had undergone hip fracture surgery. MethodsA total of 629 patients who underwent hip fracture surgery between January 2014 and December 2018 were retrospectively analyzed. Patients were classified into two groups according to preoperative CRP/albumin cut-off levels (<1.5 and ≥1.5). We performed a propensity score matching analysis to compare the incidence of postoperative delirium and overall mortality between the two groups. Multivariate logistic regression and Cox regression analyses were performed to examine the association of the preoperative CRP/albumin ratio with postoperative delirium and overall mortality. ResultsThere were significant differences in the incidence of postoperative delirium (18.0 % vs. 35.8 %, P < 0.001) and overall mortality (26.7 % vs. 46.9 %, P < 0.001) between the groups before matching. We also observed significant differences in the incidence of postoperative delirium (20.7 % vs. 32.7 %, P = 0.019) and overall mortality (34.7 % vs. 46.0 %, P = 0.046) between the groups after matching. A high CRP/albumin ratio (≥1.5) was significantly associated with a higher incidence of postoperative delirium (adjusted odds ratio [OR]: 2.11, 95 % confidence interval [CI]: 1.40–3.18, P < 0.001) and a higher rate of overall mortality (adjusted hazard ratio [HR]: 1.44, 95 % CI: 1.07–1.93, P = 0.015). ConclusionPreoperative CRP/albumin ratio might be an independent risk factor of postoperative delirium and surgical prognosis in elderly patients undergoing hip fracture surgery.

BackgroundNeurological complications is a common complication following novel triple-branched stent graft implantation in patients with Stanford type A aortic dissection (AAD). But the incidence and risk factors of postoperative delirium (POD) are not completely clear. The aim of this study was to investigate the incidence and risk factors of POD after novel triple-branched stent graft implantation.MethodsAn observational study of AAD patients who underwent novel triple-branched stent graft implantation between January 2017 and July 2019 were followed up after surgery. Patients’ delirium was screened by the Richmond Agitation-Sedation Scale and the Confusion Assessment Method for the intensive care unit from the first day after the operation, lasted 5 days. The risk factors of POD were analyzed by the Cox proportional hazard models.ResultsA total of 280 AAD patients were enrolled in this research, the incidence of POD was 37.86%. Adjusting for age, body mass index, and mechanical ventilation duration, multivariate Cox regression analysis model revealed that non-manual work (adjusted hazard ratio [AHR] = .554; 95% CI: 0.335–0.915; P = .021), Acute Physiology and Chronic Health Evaluation II (APACHE-II) scores > 20 (AHR = 3.359, 95% CI: 1.707–6.609, P < .001), hypoxemia (AHR = 1.846, 95% CI: 1.118–3.048, P = .017), and more than two types of analgesics and sedatives were independently associated with POD.ConclusionsThis study showed that risk factors independently associated with POD were APACHE-II score > 20, hypoxemia, and more types of analgesics and sedatives, and non-manual work was the protective factor.Trial registrationThis study was retrospectively registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR1900022408; Date: 2019/4/10).

BackgroundPostoperative delirium is common in elderly patients following major surgery. This study aimed to assess the effect of transcutaneous electrical acupoint stimulation combined with auricular acupressure on the incidence of postoperative delirium among older patients undergoing major abdominal surgery.MethodsIn this single-center, randomized controlled clinical trial, 210 patients aged 65 years or older undergoing major abdominal surgery were randomized to receive either intervention treatment (transcutaneous electrical acupoint stimulation started at 30 min before anesthesia until the end of the surgery, followed by intermittent auricular acupressure in the first three postoperative days; n = 105) or standard care (n = 105). The primary outcome was the incidence of delirium at the first seven postoperative days or until hospitalization depended on which came first. Secondary outcomes included delirium severity, opioid consumption, postoperative pain score, sleep quality, length of postoperative hospital stay, and postoperative 30-day complications. Enrollment was from April 2019 to March 2020, with follow-up ending in April 2020.ResultsAll of the 210 randomized patients [median age, 69.5 years, 142 (67.6%) male] completed the trial. The incidence of postoperative delirium was significantly reduced in patients received intervention treatment (19/105 (18.1%) vs. 8/105 (7.6%), difference, –10.5% [95% CI, –1.5% to –19.4%]; hazard ratio, 0.41 [95% CI, 0.18 to 0.95]; P= 0.023). Patients in the control group had a higher postoperative Memorial Delirium Assessment Scale (4 vs. 3; difference, –1; 95% CI, –1 to 0; P = 0.014) and a greater increase in Pittsburgh Sleep Quality Index score from baseline to postoperative day three (2.5 vs. 2.0; difference, –1; 95% CI, –2 to –1; P < 0.001) than patients in the intervention group. No significant difference was observed as of other secondary outcomes.ConclusionIn elderly patients undergoing major abdominal surgery, transcutaneous electrical acupoint stimulation combined with auricular acupressure reduced the incidence of postoperative in-hospital delirium compared with standard care. A multicenter, randomized clinical trial with a larger sample size is necessary to verify these findings.Clinical Trial Registration[https://clinicaltrials.gov], identifier [NCT03726073].