Risk factors for delirium after spine surgery in elderly patients

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.

Risk factors of postoperative delirium following spine surgery: A meta-analysis of 50 cohort studies with 1.1 million participants

Objectives

Postoperative delirium (POD) is considered to be a common complication of spine surgery. Although many studies have reported the risk factors associated with POD, the results remain unclear. Therefore, we performed a meta-analysis to identify risk factors for POD among patients following spinal surgery.

Methods

We systematically searched the PubMed, Embase and the Cochrane Library for relevant articles published from 2006 to February 1, 2023 that reported risk factors associated with the incidence of POD among patients undergoing spinal surgery. The Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed, and random effects models were used to estimate pooled odds ratio (OR) estimates with 95 % confidence intervals (CIs) for each factor. The evidence from observational studies was classified according to Egger's P value, total sample size, and heterogeneity between studies.

Results

Of 11,329 citations screened, 50 cohort studies involving 1,182,719 participants met the inclusion criteria. High-quality evidence indicated that POD was associated with hypertension, diabetes mellitus, cardiovascular disease, pulmonary disease, older age (>65 years), patients experiencing substance use disorder (take drug ≥1 month), cerebrovascular disease, kidney disease, neurological disorder, parkinsonism, cervical surgery, surgical site infection, postoperative fever, postoperative urinary tract infection, and admission to the intensive care unit (ICU). Moderate-quality evidence indicated that POD was associated with depression, American Society of Anesthesiologists (ASA) fitness grade (>II), blood transfusion, abnormal potassium, electrolyte disorder, length of stay, inability to ambulate and intravenous fluid volume.

Conclusions

Conspicuous risk factors for POD were mainly patient- and surgery-related. These findings help clinicians identify high-risk patients with POD following spinal surgery and recognize the importance of early intervention.

Resting-state prefrontal EEG biomarker in correlation with postoperative delirium in elderly patients

Postoperative delirium (POD) is associated with adverse outcomes in elderly patients after surgery. Electroencephalography (EEG) can be used to develop a potential biomarker for degenerative cerebral dysfunctions, including mild cognitive impairment and dementia. This study aimed to explore the relationship between preoperative EEG and POD. We included 257 patients aged >70 years who underwent spinal surgery. We measured the median dominant frequency (MDF), which is a resting-state EEG biomarker involving intrinsic alpha oscillations that reflect an idle cortical state, from the prefrontal regions. Additionally, the mini-mental state examination and Montreal cognitive assessment (MoCA) were performed before surgery as well as 5 days after surgery. For long-term cognitive function follow up, the telephone interview for cognitive status™ (TICS) was performed 1 month and 1 year after surgery. Fifty-two (20.2%) patients were diagnosed with POD. A multivariable logistic regression analysis that included age, MoCA score, Charlson comorbidity index score, Mini Nutritional Assessment, and the MDF as variables revealed that the MDF had a significant odds ratio of 0.48 (95% confidence interval 0.27-0.85). Among the patients with POD, the postoperative neurocognitive disorders could last up to 1 year. Low MDF on preoperative EEG was associated with POD in elderly patients undergoing surgery. EEG could be a novel potential tool for identifying patients at a high risk of POD.

Preoperative Risk Factors Associated with Increased Incidence of Postoperative Delirium: Systematic Review of Qualified Clinical Studies

Postoperative delirium (POD) is an acute alteration of mental state, characterized by reduced awareness and attention, occurring up to five postoperative days after recovery from anesthesia. Several original studies and reviews have identified possible perioperative POD risk factors; however, there is no comprehensive review of the preoperative risk factors in patients diagnosed with POD using only validated diagnostic scales. The aim of this systematic review was to report the preoperative risk factors associated with an increased incidence of POD in patients undergoing non-cardiac and non-brain surgery. The reviewed studies included original research papers that used at least one validated diagnostic scale to identify POD occurrence for more than 24 h. A total of 6475 references were retrieved from the database search, with only 260 of them being suitable for further review. Out of the 260 reviewed studies, only 165 that used a validated POD scale reported one or more preoperative risk factors. Forty-one risk factors were identified, with various levels of statistical significance. The extracted risk factors could serve as a preoperative POD risk assessment workup. Future studies dedicated to the further evaluation of the specific preoperative risk factors' contributions to POD could help with the development of a weighted screening tool.

Intraoperative allogeneic transfusion is associated with postoperative delirium in older patients after total knee and hip arthroplasty

Objective

To determine whether intraoperative transfusion of allogeneic or autologous blood is associated with an increased incidence of postoperative delirium (POD) after total knee arthroplasty (TKA) and total hip arthroplasty (THA).

Methods

The medical records of 1,143 older (≥65 years old) patients who received an intraoperative blood transfusion while undergoing total knee or hip arthroplasty at the First Medical Center of Chinese PLA General Hospital from 2014 to 2019 were reviewed; of these patients, 742 (64.92%) received allogeneic blood, while 401 (35.08%) received autologous blood. Patients who received autologous transfusion were paired with those received allogeneic transfusion using 1:1 propensity score matching method. The primary outcome was POD. The secondary outcomes were postoperative complications, including heart failure, deep vein thrombosis, myocardial infarction, stroke, and lung infection. Multivariable nominal logistic regression was used to identify any independent associations between intraoperative blood transfusions and POD, and secondary postoperative complications, respectively.

Results

Postoperative delirium occurred in 6.6% (49/742) of patients who had received an allogeneic blood transfusion and in 2.0% (8/401) of patients who had received an autologous blood transfusion. It is noteworthy that the multivariable logistic regression demonstrated a significant association between intraoperative allogeneic blood transfusion and POD (odds ratio [OR]: 4.11; 95% confidence interval [CI]: 1.95-9.77; p < 0.001). After PSM, Allogeneic transfusion was also the strongest predictor for POD (OR: 4.43; 95% CI: 2.09-10.58; p < 0.001).

Conclusions

In the patients who had received THA or TKA, intraoperative allogeneic blood transfusions were associated with an increased risk of POD.

The influence of orthopedic surgery on the incidence of post-operative delirium in geriatric patients: results of a prospective observational study

Background

Postoperative delirium (PD) is a major concern in geriatric patients undergoing orthopedic surgery. This prospective observational study aims to examine the incidence of PD, to identify intervention-specific risk factors and to investigate the influence of orthopedic surgery on delirium.

Methods

From 2019 to 2020, 132 patients ≥70 years of age with endoprosthetic (Group E) or spinal surgery (Group S) were included. Upon admission, the ISAR score, the Nursing Delirium Screening Scale, potential risk factors, the ASA score, duration of surgery, type of anesthesia, blood loss, and hemoglobin drop were recorded. For risk factor analysis patients were grouped into Group D (delirium) and Group ND (no delirium). Primary endpoint was the occurrence of PD.

Results

Of 132 patients, 50 were included in Group E and 82 in Group S. Mean age and ISAR score were not significantly different between groups. Delirium rate in Group E and S was 12% vs. 18% (p = 0.3). Differences could be observed between Group D and ND in duration of surgery (173 min vs. 112 min, p = 0.02), postoperative hemoglobin drop (3.2 g/dl vs. 2.3 g/dl; p = 0.026), history of PD (23% vs. 11%, p = 0.039) and use of isoflurane (6 vs. 2). Type of surgery was not an independent risk factor (p = 0.26).

Conclusion

Specific type of orthopedic surgery is not an independent risk factor for PD. Prevention of PD should focus on duration of surgery and blood loss, particularly in patients with a history of PD. A possible delirogenic potential of isoflurane should be further studied.

REGIONAL ANESTHESIA IN SPINAL SURGERY: COULD IT BE THE SOLUTION FOR DIFFICULT INTUBATION

This article includes two topics - anesthesia for spinal surgery and difficult airway, both of them are linked with the same topic, which is regional anesthesia. In recent years, regional anesthesia for spinal surgery has gained a great popularity, where neuraxial blocks are the first choice. Regional anesthesia seems to have benefits against general anesthesia due to lower rate of perioperative and postoperative complications, lower cost and length of stay. This is more evident in elderly population or patients with comorbidities. On the other hand, difficult airway is the life threatening condition and requires increased attention. There are many methods and tools for managing difficult airways, but there are few supporters of regional anesthesia as an option or solution in these cases. Of course, special attention is required during regional anesthesia in a patient with difficult airway, the decision must be correct, and an anesthesiologist must have a preformulated strategy for airway management. However, does not the same happen even when we apply general anesthesia?

Impact of propofol versus sevoflurane on the incidence of postoperative delirium in elderly patients after spine surgery: study protocol of a randomized controlled trial

Background

Postoperative delirium in elderly patients is a common and costly complication after surgery. Propofol and sevoflurane are commonly used anesthetics during general anesthesia, and the sedative and anti-inflammatory mechanisms of the two medications are different. The aim of this trial is to compare the impact of propofol with sevoflurane on the incidence of postoperative delirium in elderly patients after spine surgery.

Methods

A single-center randomized controlled trial will be performed at First Affiliated Hospital of Shandong First Medical University, China. A total of 298 participants will be enrolled in the study and randomized to propofol infusion or sevoflurane inhalation groups. The primary outcome is the incidence of delirium within 7 days after surgery. Secondary outcomes include the day of postoperative delirium onset, duration (time from first to last delirium-positive day), and total delirium-positive days among patients who developed delirium; tracheal intubation time in PACU; the length of stay in PACU; the rate of postoperative shivering; the rate of postoperative nausea and vomiting; the rate of emergence agitation; pain severity; QoR40 at the first day after surgery; the length of stay in hospital after surgery; and the incidence of non-delirium complications within 30 days after surgery.

Discussion

The primary objective of this study is to compare the impact of propofol and sevoflurane on the incidence of postoperative delirium for elderly patients undergoing spine surgery. The results may help inform strategies to the optimal selection of maintenance drugs for general anesthesia in elderly patients undergoing spine surgery.

Trial registration

ClinicalTrials.govNCT05158998. Registered on 14 December 2021

Post-Operative Cognitive Impairment: A Cognitive Epidemiology Perspective

Cognitive epidemiology investigates cognitive predictors of health and disease outcomes. Post-operative cognitive impairment is a common complication of surgery but has been neglected as a health outcome in cognitive epidemiology research. This is despite the fact that knowledge of cognitive predictors of post-operative cognitive impairment can be utilized for risk stratification, informed decision-making (in elective surgery), and personalized care of patients during the postoperative period. In this narrative review, the current literature on cognitive predictors of post-operative cognitive impairment and gaps therein are summarized.

Complications of adult spinal deformity surgery: A literature review

Purpose:

Adult spinal deformity incidence increases accordingly as the population ages. Even though surgery is the best option for the treatment, the complications due to surgery are pretty challenging. This study aims to review the complication rates of adult spinal deformity surgery.

Methods:

A literature review of the last decade was performed searching for the query “Adult spine deformity and complication.” This search yielded 2781 results, where 79 articles were chosen to investigate the complications of adult spinal deformity surgery. In addition, the demographic data, surgical interventions, and complications were extracted from the publications.

Results:

A total of 26,207 patients were analyzed, and 9138 complications were found (34.5%). Implant failure, including screw loosening, breakage, distal and proximal junctional kyphosis, were the most common complications. The neurologic complications were about 10.8%, and the infection rate was 3.6%. Cardiac and pulmonary complications were about 4.8%.

Discussion:

Age, body mass index, smoking, osteoporosis, and other comorbidities are the significant risk factors affecting adult spinal deformity surgery. Presurgical planning and preoperative risk factor assessment must be done to avoid complications. Furthermore, intra and postoperative complications affect the patients’ quality of life and length of stay, and hospital readmissions. Revision surgery also increases the risk of complications.

Conclusion:

Good patient evaluation before surgery and careful planning of the surgery are essential in avoiding complications of adult spinal deformity.

Risk Factors and a Nomogram Model Establishment for Postoperative Delirium in Elderly Patients Undergoing Arthroplasty Surgery: A Single-Center Retrospective Study

Objective

To explore the related risk factors of postoperative delirium (POD) after hip or knee arthroplasty in elderly orthopedic patients and the predictive value of related risk factors. Material and Methods. In total, 309 patients (≥60 years) who received knee and hip arthroplasty between January 2017 and May 2020 were consecutively selected into the POD and nonpostoperative delirium (NPOD) groups. Group bias was eliminated through propensity score matching. Univariate and multivariable logistic analysis was used to determine the risk factors for POD. The nomogram was made by R.

Results

58 patients were included in each group after propensity score matching; multivariable analysis demonstrated that LDH (OR = 4.364, P = 0.017), CHE (OR = 4.640, P = 0.004), Cystatin C (OR = 5.283, P = 0.006), arrhythmia (OR = 5.253, P = 0.002), and operation duration (OR = 1.017, P = 0.050) were independent risk factors of POD. LDH, CHE, Cystatin C, and arrhythmia were used to construct a nomogram to predict the POD. The nomogram was well calibrated and had moderate discriminative ability (AUC = 0.821, 95% CI: 0.760~0.883). Decision curve analysis demonstrated that the nomogram was clinically useful.

Conclusions

Our study revealed that arrhythmia, operation duration, the increase of lactate dehydrogenase and Cystatin C, and the decrease of cholinesterase were reliable factors for predicting postoperative delirium after elderly hip and knee arthroplasty. Meanwhile, the nomogram we developed can assist the clinician to filtrate potential patients with postoperative delirium.

Prevalence and Factors Affecting Postoperative Delirium in a Neurosurgical Intensive Care Unit

ABSTRACT

PURPOSE: The aim of this study was to identify the prevalence of, and factors affecting, postoperative delirium (POD) in patients in the neurosurgical intensive care unit. METHODS: A cross-sectional study of 127 Turkish neurosurgical intensive care unit patients admitted between May 2018 and May 2019 was conducted. Patients were assessed for the development of POD using the Intensive Care Delirium Screening Checklist. We collected other independent data variables daily. Data were analyzed using independent sample t test, χ2 test, and logistic regression. RESULTS: The prevalence rates of POD on the first and second postoperative days were 18.9% and 8.7%, respectively. Logistic regression analysis showed that the Glasgow Coma Scale score, albumin level, Spo2 level, hemoglobin values, undergoing cranial surgery, and having intra-arterial catheter were the independent risk factors for POD. CONCLUSION: These findings may contribute to identifying patients at risk for developing POD and developing strategies to improve patient outcomes.

Risk Factors of Postoperative Delirium in Older Adult Spine Surgery Patients: A Meta-Analysis

This literature review identifies factors that may place older adult patients at risk for developing delirium after spine surgery. We conducted a meta-analysis according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Using a variety of electronic databases, we identified five studies for inclusion that represent 645 patients who were 65 years or older. The pooled incidence rate of postoperative delirium was 13.0%. Factors associated with developing postoperative delirium included preoperative opioid use, cervical spine surgery versus lumbar or thoracic spine surgery, spine fusion versus simple spine surgery, hypertension, cerebrovascular disease, pulmonary disease, duration of surgery, and infused IV fluid volume. Nurses who provide perioperative care for older adult patients undergoing spine surgery should be aware of the potential risk factors of delirium to ensure patient safety. Further research is required to clearly delineate the risk factors for postoperative delirium in older adults.

Systematic review and meta-analysis of risk factor for postoperative delirium following spinal surgery

Background

Postoperative delirium is a common psychiatric disorder among patients who undergo spinal surgery. The purpose of current meta-analysis was to assess the potential risk factors related to delirium in spinal surgery.

Methods

We searched the following databases: PubMed, EMBASE, the Cochrane Library, and Web of Science, from inception to July 2020. Two reviewers independently assessed the quality of the included studies using the previously described Newcastle-Ottawa Scale (NOS). We included spinal surgery patients who suffered with delirium or not. Stata 12.0 was used for meta-analysis.

Results

Thirteen trial studies that met our inclusion criteria were incorporated into the meta-analysis. Postoperative delirium was associated with an increase of the duration of hospital stay (P = 0.044) and increased perioperative readmission rate (P = 0.013) and economic costs (P = 0.002). This meta-analysis demonstrates that there were twenty-two risk factors: general characteristic: old age, female patients, history of surgery, diabetes mellitus, hypertension; preoperative data: low hematocrit, low hemoglobin, low albumin, low sodium, depression; operative data: operating time, total blood loss; postoperative data: low sodium, low hemoglobin, low hematocrit, low albumin, fever, low potassium, blood sugar, and visual analog scale (VAS).

Conclusions

Delirium not only prolongs the length of hospital stay, but also increases readmission rate and the economic costs. Several risk factors including old age, female patients, history of surgery, diabetes mellitus, low hematocrit, low hemoglobin, low albumin, low sodium, depression; operative data: operating time, total blood loss, low sodium, low hemoglobin, low hematocrit, low albumin, fever, low potassium, blood sugar, and VAS were significant predictors for postoperative delirium after spinal surgery.

Risk factors for postoperative delirium after spinal surgery: a systematic review and meta-analysis

BACKGROUND

Postoperative delirium is common in older patients after spinal surgery. Many reports investigating the risk factors for delirium after spinal surgery have been published recently.

METHODS

A literature search was performed using the Cochrane Library, Web of Science, PubMed, Embase, and Springer databases from inception to February 2019. Relevant studies involving patients with delirium who underwent spinal surgery were included if the studies contained data about blood transfusion or other related factors, such as haemoglobin, haematocrit, and blood loss levels. The Newcastle-Ottawa Scale was used for the study-quality evaluation. The pooled odds ratios or (standard) mean differences of the individual risk factors were estimated using the Mantel-Haenszel or inverse-variance methods.

RESULTS

Fifteen observational studies met the inclusion criteria; the studies included a total of 583,290 patients (5431 patients with delirium and 577,859 patients without delirium). In addition to an advanced age, the results of the meta-analyses showed that living in an institution, diabetes, cerebral vascular diseases, pulmonary diseases, opioid use, length of surgery, intraoperative blood loss, blood transfusions, intraoperative infusion, preoperative albumin, postoperative albumin, preoperative haematocrit, postoperative haematocrit, preoperative haemoglobin, postoperative haemoglobin, preoperative sodium, postoperative sodium, Mini-Mental State Examination score, inability to ambulate, depression, number of medications, and treatment with multiple drugs (> three types) were significantly associated with delirium.

CONCLUSION

The above-mentioned risk factors can be used to identify high-risk patients, and the appropriate prophylaxis strategies should be implemented to prevent delirium after spinal surgery.

Efficacy of Intervention for Prevention of Postoperative Delirium after Spine Surgery

Introduction

Delirium after spine surgery is an important complication; identification of risk factors associated with postoperative delirium (PD) is essential for reducing its incidence. Prophylactic intervention for PD has been reported to be effective. This study aimed to identify risk factors for PD and determine the efficacy of a prevention program using a delirium risk scoring system for PD after spine surgery.

Methods

This study was conducted in two stages. First, 294 patients (167 males, 127 females) who underwent spine surgery from 2013 to 2014 were assessed to examine the incidence and risk factors of PD and to establish a novel PD screening tool (Group A). Second, preoperative intervention was performed on 265 patients who underwent surgery from 2016 to 2017 (Group B) for the purpose of preventing PD using a delirium risk scoring system. Outcomes, including PD incidence and rates of adverse events, were compared between Group A and Group B.

Results

A logistic regression analysis revealed that psychiatric disorders (odds ratio [OR] = 10.3, P < 0.001), benzodiazepine use (OR = 4.9, P < 0.001), age > 70 years (OR = 4.2, P < 0.001), hearing loss (OR = 3.7, P = 0.001), and admission to intensive care unit (ICU) (OR = 3.7, P = 0.006) were independent risk factors associated with PD. Based on these results, we established a novel delirium screening tool after spine surgery. PD incidence was significantly higher in Group A than in Group B (22% vs. 13%, P = 0.0008). The occurrence of dangerous behavioral symptoms was significantly higher in Group A than in Group B (66% vs. 40%, P = 0.02). The catheter problem tended to be higher in Group A than in Group B (19% vs. 9%, P = 0.245).

Conclusions

In this study, psychiatric disorders, benzodiazepine use, age > 70 years, hearing loss, and admission to ICU were independent risk factors associated with PD. With the introduction of the delirium risk score, the onset of delirium was delayed, and adverse outcomes of delirium were reduced.

Prevalence and risk factors of postoperative delirium after spinal surgery: a meta-analysis

OBJECTIVE

Postoperative delirium (POD) was common after spinal surgery, but the main findings in previous studies remained conflicting. This current meta-analysis was aimed at exploring the prevalence and risk factors of POD after spinal surgery.

METHODS

PubMed and Embase were searched from inception to June 2019. Studies which reported the prevalence and risk factors of POD after spinal surgery were included. STATA version 12.0 was employed to analyze the pooled data. Statistical heterogeneity across included studies was identified using the I2 statistics.

RESULTS

A total of 28 studies with 588,732 patients were included in the meta-analysis. The pooled prevalence of POD after spinal surgery was 0.85% (95%CI, 0.83-0.88%) with substantial heterogeneity (I2 = 97.3%). The central nervous system disorder (OR 4.73; 95%CI, 4.30-5.19) was a strong predictor for POD, whereas age (OR 1.16; 95%CI, 1.05-2.47; I2 = 99.2%) and blood loss (OR 1.10; 95%CI, 1.01-1.20; I2 = 93.3%) were weaker predictors. The funnel plot and statistical tests suggested that there existed potential publication bias, but the trim and fill method indicated that the pooled prevalence basically kept stable after adding two "missing" studies.

CONCLUSIONS

The pooled POD after spinal surgery ranges from 0.83 to 0.88%. The central nervous system disorder, age, and blood loss were potential risk factors for POD.

Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial

Background

Elderly people are at particular high risk for postoperative delirium (POD) following spine surgery, which is associated with longer hospital stays, higher costs, risk for delayed complications, long-term care dependency, and cognitive dysfunction (POCD). It is insufficiently understood which mechanisms and risk factors contribute to the development of POD and POCD following these major but plannable surgeries.

Objective

This study aims to identify modifiable risk factors in spine surgery. A better understanding thereof would help adapt medical management and surgical strategies to individual risk profiles.

Methods

This is a single-center observational study jointly conducted by the departments of neurosurgery, neurology, and anesthesiology at a tertiary care hospital in Germany. All patients aged 60 years and older presenting to the neurosurgery outpatient clinic or ward for elective spine surgery are screened for eligibility. Exclusion criteria include presence of neurodegenerative or history of psychiatric disease and medication with significant central nervous system activity (eg, antidepressants, antipsychotics, sedatives). Surgical and anesthetic procedures including duration of surgery as primary end point of this study are thoroughly documented. All patients are furthermore evaluated for their preoperative cognitive abilities by a number of tests, including the Consortium to Establish a Registry for Alzheimer's Disease Plus test battery. Physical, mental, and social health and well-being are assessed using the Patient-Reported Outcome Measurement Information System Profile 29 and Hospital Anxiety and Depression Scale. Patients additionally receive preoperative cerebrovascular ultrasound and structural and functional brain imaging. The immediate postoperative period includes screening for POD using the Nursing Delirium Screening Scale and validation through Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. We furthermore investigate markers of (neuro)inflammation (eg, interleukins, C-reactive protein, tumor necrosis factor alpha). Preoperative examinations are repeated 3 months postoperatively to investigate the presence of POCD and its mechanisms. Statistical analyses will compare delirious and nondelirious patients for predictors of immediate (POD) and delayed (POCD) cognitive dysfunction.

Results

This is the first study to prospectively evaluate risk factors for POD and POCD in spine surgery. Recruitment is ongoing, and data collection is estimated to be finished with the inclusion of 200 patients by mid-2020.

Conclusions

The identification of mechanisms, possibly common, underlying POD and POCD would be a major step toward defining effective interventional strategies early in or even before the postoperative period, including the adaptation of surgical strategies to individual risk profiles.

Trial Registration

ClinicalTrials.gov NCT03486288; https://clinicaltrials.gov/ct2/show/NCT03486288

Incidence and Risk Factors for Postoperative Delirium in Patients Undergoing Spine Surgery: A Systematic Review and Meta-Analysis

Background

The present study aims to investigate the incidence and risk factors associated with postoperative delirium in patients undergoing spine surgery.

Methods

PubMed, EMBASE, Cochrane Library, and Science Citation Index were searched up to August 2019 for studies examining postoperative delirium following spine surgery. Incidence and risk factors associated with delirium were extracted. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for outcomes. The Newcastle-Ottawa Scale (NOS) was used for the study quality evaluation.

Results

The final analysis includes a total of 40 studies. The pooled analysis reveals that incidence of delirium is 8%, and there are significant differences for developing delirium in age (OR 1.07; 95% CI 1.04-1.09), age more than 65 (OR 4.77; 95% CI 4.37-5.16), age more than 70 (OR 15.87; 95% CI 6.03-41.73), and age more than 80 (OR 1.91; 95% CI 1.78-2.03) years, male (OR 0.81; 95% CI 0.76-0.86), a history of alcohol abuse (OR 2.11; 95% CI 1.67-2.56), anxiety (OR 1.74; 95% CI 1.04-2.44), congestive heart failure (OR 1.4; 95% CI 1.21-1.6), depression (OR 2.5; 95% CI 1.52-3.49), hypertension (OR 1.12; 95% CI 1.04-1.2), kidney disease (OR 1.41; 95% CI 1.16-1.66), neurological disorder (OR 4.66; 95% CI 4.22-5.11), opioid use (OR 1.86; 95% CI 1.18-2.54), psychoses (OR 2.77; 95% CI 2.29-3.25), pulmonary disease (OR 1.81; 95% CI 1.27-2.35), higher mini-mental state examination (OR 0.7; 95% CI 0.5-0.89), preoperative pain (OR 1.88; 95% CI 1.11-2.64), and postoperative urinary tract infection (OR 5.68; 95% CI 2.41-13.39).

Conclusions

A comprehensive understanding of incidence and risk factors of delirium can improve prevention, diagnosis, and management. Risk of postoperative delirium can be reduced based upon identifiable risk factors.

SF-36 scores predict postoperative delirium after surgery for cervical spondylotic myelopathy

OBJECTIVE

Cervical spondylotic myelopathy (CSM) is one of the most common causes of spinal cord dysfunction. Surgery for CSM is generally effective, but postoperative delirium is a potential complication. Although there have been some studies that investigated postoperative delirium after spine surgery, no useful tool for identifying high-risk patients has been established, and it is unknown if 36-Item Short Form Health Survey (SF-36) scores can predict postoperative delirium. The objective of this study was to evaluate the correlation between preoperative SF-36 scores and postoperative delirium after surgery for CSM.

METHODS

Sixty-seven patients who underwent surgery for CSM at the authors' institution were enrolled in this study. Medical records of these patients were retrospectively reviewed. Patient background, preoperative laboratory data, preoperative SF-36 scores, the preoperative Japanese Orthopaedic Association (JOA) score for the evaluation of cervical myelopathy, and perioperative factors were selected as potential risk factors for postoperative delirium. These factors were evaluated using univariable and multivariable logistic regression analysis.

RESULTS

Ten patients were diagnosed with postoperative delirium. Univariable analysis revealed that the physical functioning score (p = 0.01), general health perception score (p < 0.01), and vitality score (p < 0.01) of the SF-36 were significantly lower in patients with postoperative delirium than in those without. The total number of medications was significantly higher in the delirium group compared with the no-delirium group (p = 0.02). In contrast, there were no significant differences between the delirium group and the no-delirium group in cervical JOA scores (p = 0.20). Multivariable analysis revealed that a low general health perception score was an independent risk factor for postoperative delirium (p = 0.02; odds ratio 0.810, 95% confidence interval 0.684-0.960).

CONCLUSIONS

Some of the SF-36 scores were significantly lower in patients with postoperative delirium than in those without. In particular, the general health perception score was independently correlated with postoperative delirium. SF-36 scores could help identify patients at high risk for postoperative delirium and aid in the development of prevention strategies.

Surgical Risk Assessment and Prevention in Elderly Spinal Deformity Patients

Introduction:

Prevalence of adult deformity surgery in the elderly individuals continues to increase. These patients have additional considerations for the spine surgeon during surgical planning. We perform an informative review of the spinal and geriatric literature to assess preoperative and intraoperative factors that impact surgical complication occurrences in this population.

Significance:

There is a need to understand surgical risk assessment and prevention in geriatric patients who undergo thoracolumbar adult deformity surgery in order to prevent complications.

Methods:

Searches of relevant biomedical databases were conducted by a medical librarian. Databases searched included MEDLINE, Web of Science, CINAHL, IPA, Cochrane, PQ Health and Medical, SocINDEX, and WHO’s Global Health Library. Search strategies utilized Medical Subject Headings plus text words for extensive coverage of scoliosis and surgical technique concepts.

Results:

Degenerative scoliosis affects 68% of the geriatric population, and the rate of surgical interventions for this pathology continues to increase. Complications following spinal deformity surgery in this patient population range from 37% to 62%. Factors that impact outcomes include age, comorbidities, blood loss, and bone quality. Using these data, we summarize multimodal risk prevention strategies that can be easily implemented by spine surgeons.

Conclusions:

After evaluation of the latest literature on the complications associated with adult deformity surgery in geriatric patients, comprehensive perioperative management is necessary for improved outcomes. Preoperative strategies include assessing physiological age via frailty score, nutritional status, bone quality, dementia/delirium risk, and social activity support. Intraoperative strategies include methods to reduce blood loss and procedural time. Postoperatively, development of a multidisciplinary team approach that encourages early ambulation, decreases opiate use, and ensures supportive discharge planning is imperative for better outcomes for this patient population.

The risk factors associated with delirium after lumbar spine surgery in elderly patients

Background

To prospectively explore the incidence and risk factors for postoperative delirium in elderly patients following lumbar spine surgery.

Methods

This prospective study enrolled 148 consecutive patients over the age of 65 who were scheduled to undergo spine surgery. Patients were screened for delirium using the short Confusion Assessment Method (CAM) postoperatively. Patient demographics and relevant medical information were collected. Logistic regression analysis was used to identify the risk factors associated with postoperative delirium.

Results

Eighty-three patients (56.1%) who underwent lumbar spine surgery (not coexisting with cervical or thoracic spine surgery) were enrolled in our study. Post-operative delirium was noted in 14.5% of patients over 65 years old. The presence of preoperative Parkinsonism was significantly higher in the delirium group (41.7% vs. 8.5%, P=0.002), as was a higher preoperative C-reactive protein (CRP) (7.0±15.2 vs. 1.3±2.3 mg/L, P=0.017) when compared with the non-delirium group. Of the risk factors, male sex [odds ratio (OR) =0.10, 95% confidence interval (CI): 0.01-0.66, P=0.017], Parkinsonism (OR =5.83, 95% CI: 1.03-32.89, P=0.046), and lower baseline MMSE score (OR =0.71, 95% CI: 0.52-0.97, P=0.032) were independently associated with postoperative delirium in elderly patients undergoing lumbar spine surgery.

Conclusions

Post-operative delirium occurred in 14.5% of elderly patients who underwent lumbar spine surgery. Male sex, Parkinsonism, and lower baseline MMSE score were identified as independent risk factors for postoperative delirium in elderly patients following lumbar surgery.

The Motoric Types of Delirium and Estimated Blood Loss during Perioperative Period in Orthopedic Elderly Patients

Background

Delirium is a common and serious syndrome in elderly patients. The hypoactive type of delirium is known to have different characteristics, but further studies are needed to define the specificities of these characteristics. Our study aims at finding specific risk factors, especially estimated blood loss during operations of hyper- and hypoactive delirium in orthopedic elderly patients.

Methods

One hundred and seventy-five elderly patients were evaluated using the Confusion Assessment Method (CAM) and the 4^th edition text revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Trained psychiatrists interviewed the subjects directly at pre- and postoperative time points. We reviewed medical records after the patients were discharged.

Results

Thirty-nine patients (22.3%) were diagnosed with multiple types of delirium, which included 17 hyperactive types (65.9%), 13 hypoactive types (33.3%), and 9 mixed types (23.1%). Although the mean estimated blood loss in patients with either hyper- or hypoactive symptoms was larger than in patients lacking these symptoms, the odds ratio was only significant in patients with hyperactive symptoms. In addition, age, preoperative daily function, and preoperative hyponatremia were found to be risk factors for hyperactive but not hypoactive symptoms.

Conclusion

Patients with hypoactive symptoms had different risk factors than patients with hyperactive symptoms of delirium. The estimated blood loss, well-known risk factors for delirium, might be risk factors for only hyperactive delirium. The acute precipitating factors seemed to show stronger correlation with the hyperactive type of delirium than with the hypoactive type.

Processed electroencephalogram and evoked potential techniques for amelioration of postoperative delirium and cognitive dysfunction following non-cardiac and non-neurosurgical procedures in adults

BACKGROUND

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) may complicate a patient's postoperative recovery in several ways. Monitoring of processed electroencephalogram (EEG) or evoked potential (EP) indices may prevent or minimize POD and POCD, probably through optimization of anaesthetic doses.

OBJECTIVES

To assess whether the use of processed EEG or auditory evoked potential (AEP) indices (bispectral index (BIS), narcotrend index, cerebral state index, state entropy and response entropy, patient state index, index of consciousness, A-line autoregressive index, and auditory evoked potentials (AEP index)) as guides to anaesthetic delivery can reduce the risk of POD and POCD in non-cardiac surgical or non-neurosurgical adult patients undergoing general anaesthesia compared with standard practice where only clinical signs are used.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and clinical trial registry databases up to 28 March 2017. We updated this search in February 2018, but these results have not been incorporated in the review.

SELECTION CRITERIA

We included randomized or quasi-randomized controlled trials comparing any method of processed EEG or evoked potential techniques (entropy, BIS, AEP etc.) against a control group where clinical signs were used to guide doses of anaesthetics in adults aged 18 years or over undergoing general anaesthesia for non-cardiac or non-neurosurgical elective operations.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Our primary outcomes were: occurrence of POD; and occurrence of POCD. Secondary outcomes included: all-cause mortality; any postoperative complications; and postoperative length of stay. We used GRADE to assess the quality of evidence for each outcome.

MAIN RESULTS

We included six randomized controlled trials (RCTs) with 2929 participants comparing processed EEG or EP indices-guided anaesthesia with clinical signs-guided anaesthesia. There are five ongoing studies and one study awaiting classification.Anaesthesia administration guided by the indices from a processed EEG (bispectral index) probably reduces the risk of POD within seven days after surgery with risk ratio (RR) of 0.71 (95% CI 0.59 to 0.85; number needed to treat for an additional beneficial outcome (NNTB) of 17, 95% CI 11 to 34; 2197 participants; 3 RCTs; moderate quality of evidence). Three trials also showed the lower rate of POCD at 12 weeks after surgery (RR 0.71, 95% CI 0.53 to 0.96; NNTB 38, 95% CI 21 to 289; 2051 participants; moderate-quality evidence), but it is uncertain whether processed EEG indices reduce POCD at one week (RR 0.84, 95% CI 0.69 to 1.02; 3 trials; 1989 participants; moderate-quality evidence), and at 52 weeks (RR 0.30, 95% CI 0.05 to 1.80; 1 trial; 59 participants; very low quality of evidence). There may be little or no effect on all-cause mortality (RR 1.01, 95% CI 0.62 to 1.64; 1 trial; 1155 participants; low-quality evidence). One trial suggested a lower risk of any postoperative complications with processed EEG (RR 0.51, 95% CI 0.37 to 0.71; 902 participants, moderate-quality evidence). There may be little or no effect on reduced postoperative length of stay (mean difference -0.2 days, 95% CI -2.02 to 1.62; 1155 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

There is moderate-quality evidence that optimized anaesthesia guided by processed EEG indices could reduce the risk of postoperative delirium in patients aged 60 years or over undergoing non-cardiac surgical and non-neurosurgical procedures. We found moderate-quality evidence that postoperative cognitive dysfunction at three months could be reduced in these patients. The effect on POCD at one week and over one year after surgery is uncertain. There are no data available for patients under 60 years. Further blinded randomized controlled trials are needed to elucidate strategies for the amelioration of postoperative delirium and postoperative cognitive dysfunction, and their consequences such as dementia (including Alzheimer's disease (AD)) in both non-elderly (below 60 years) and elderly (60 years or over) adult patients. The one study awaiting classification and five ongoing studies may alter the conclusions of the review once assessed.

Association between baseline cognitive impairment and postoperative delirium in elderly patients undergoing surgery for adult spinal deformity

OBJECTIVE Postoperative delirium is common in elderly patients undergoing spine surgery and is associated with a longer and more costly hospital course, functional decline, postoperative institutionalization, and higher likelihood of death within 6 months of discharge. Preoperative cognitive impairment may be a risk factor for the development of postoperative delirium. The aim of this study was to investigate the relationship between baseline cognitive impairment and postoperative delirium in geriatric patients undergoing surgery for degenerative scoliosis. METHODS Elderly patients 65 years and older undergoing a planned elective spinal surgery for correction of adult degenerative scoliosis were enrolled in this study. Preoperative cognition was assessed using the validated Saint Louis University Mental Status (SLUMS) examination. SLUMS comprises 11 questions, with a maximum score of 30 points. Mild cognitive impairment was defined as a SLUMS score between 21 and 26 points, while severe cognitive impairment was defined as a SLUMS score of ≤ 20 points. Normal cognition was defined as a SLUMS score of ≥ 27 points. Delirium was assessed daily using the Confusion Assessment Method (CAM) and rated as absent or present on the basis of CAM. The incidence of delirium was compared in patients with and without baseline cognitive impairment. RESULTS Twenty-two patients (18%) developed delirium postoperatively. Baseline demographics, including age, sex, comorbidities, and perioperative variables, were similar in patients with and without delirium. The length of in-hospital stay (mean 5.33 days vs 5.48 days) and 30-day hospital readmission rates (12.28% vs 12%) were similar between patients with and without delirium, respectively. Patients with preoperative cognitive impairment (i.e., a lower SLUMS score) had a higher incidence of postoperative delirium. One- and 2-year patient reported outcomes scores were similar in patients with and without delirium. CONCLUSIONS Cognitive impairment is a risk factor for the development of postoperative delirium. Postoperative delirium may be associated with decreased preoperative cognitive reserve. Cognitive impairment assessments should be considered in the preoperative evaluations of elderly patients prior to surgery.

Risk factors for postoperative delirium after spine surgery in middle- and old-aged patients

BACKGROUND

Postoperative delirium is a common complication following various operative procedures with an incidence rate of 10-77 %.

AIM

To analyze various risk factors for postoperative delirium after spine surgery in the middle- and old-aged patients.

METHODS

This study retrospectively reviewed 451 patients (226 males and 225 females, an average age of 65.1 ± 18.3 years) who underwent spinal surgery in our hospital between January 2010 and August 2015. Patients who had features of acute onset and fluctuating course and any two of the other features were diagnosed with delirium. Cognitive tests consisting of Clinical Dementia Rating and Global Deterioration Scale were performed to evaluate delirium. T tests were used for statistical analysis of the difference between the two groups, and logistic regression analyses were used for determining the risk factors.

RESULTS

A total of 42 (9.3 %) patients were diagnosed with delirium. Delirious and non-delirious patients had no difference in age, gender, BMI, education level, drug treatment, comorbid disease history, surgical history, preoperative blood pressure, intraoperative blood loss, blood transfusion, use of surgical implants, surgical site, use of fentanyl and propofol, and preoperative VAS score. Intraoperative hypotension and use of dezocine were related to postoperative delirium (P = 0.03 and P = 0.07). The multiple regression equation was Y = -0.11 + 0.52 × X ₀ + 0.21 × X ₁, where X ₀ = amount of dezocine, X ₁ = instances of intraoperative hypotension.

CONCLUSION

Postoperative delirium commonly occurs after spine surgery. Intraoperative hypotension <80 mmHg and intraoperative use of dezocine represent valuable new predictors of the risk of delirium.

Environmental and Clinical Risk Factors for Delirium in a Neurosurgical Center: A Prospective Study

BACKGROUND

Few reports of delirium-related risk factors have focused on environmental risk factors and clinical risk factors, such as white matter signal abnormalities on magnetic resonance imaging fluid attenuated inversion recovery images.

METHODS

We prospectively enrolled 253 patients admitted to our neurosurgical center between December 2014 and June 2015 and analyzed 220 patients (100 male patients; mean age, 64.1 years; age range, 17-92 years). An Intensive Care Delirium Screening Checklist score ≥4 points indicated delirium. We evaluated patient factors consisting of baseline characteristics and related factors, such as white matter lesions (WMLs), as well as the surrounding environment.

RESULTS

Delirium occurred in 29/220 cases (13.2%). Regarding baseline characteristics, there were significant statistical correlations between delirium and age (P = 0.0187), Hasegawa Dementia Scale-Revised score (P = 0.0022) on admission, and WMLs (P < 0.0001). WMLs were related to age (P < 0.0001) and atherosclerotic disease (P = 0.004). Regarding related factors, there were significant statistical correlations between delirium and stay in a neurosurgical care unit (P = 0.0245). Multivariate logistic regression analyses showed statistically significant correlations of delirium with WMLs (P < 0.0001) and surrounding patients with delirium (P = 0.026).

CONCLUSIONS

WMLs in patients and the surrounding environment are risk factors for delirium in a neurosurgical center. To prevent delirium, clinicians must recognize risk factors, such as high-grade WMLs, and manage environmental factors.

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.

Pathological changes of the hippocampus and cognitive dysfunction following frontal lobe surgery in a rat model

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a known complication after intracranial surgery. Impaired hippocampal neurogenesis has been associated with cognitive dysfunction in animal models.

METHODS

In order to assess hippocampal changes after brain surgery, a frontal lobe corticectomy was performed in ten adult Wistar rats (group 4). Three different control groups (n = 10 each) included no treatment (G1), general anesthesia alone (G2), and craniectomy without dural opening (G3). Twenty-four hours after surgery, half of the animals were killed, and the mRNA levels for IL-6, TNF-α, and brain-derived growth factor (BDNF) in the contralateral hippocampus were assessed by qPCR. Seven days later, the remaining animals underwent anxiety and memory testing. Afterwards, the number of immature neurons in the hippocampal cortex was measured by doublecortin (DCX) staining.

RESULTS

Twenty-four hours after surgery, mRNA levels of IL-6 and TNF-α increased and BDNF decreased in both surgical groups G3 and G4 (p = 0.012). Cognitive tests demonstrated an increase in anxiety levels and memory impairment in surgical groups compared with non-surgical animals. These changes correlated with an inhibition of hippocampal neurogenesis evidenced by a decreased number of new neurons (mean ± SD for G1-4: 66.4 ± 24; 57.6 ± 22.2; 21.3 ± 3.78; 5.7 ± 1.05, p < 0.001, non-parametric ANOVA).

CONCLUSIONS

Intracranial surgery was demonstrated to induce an inflammatory reaction within the hippocampus that compromised neurogenesis and impaired normal cognitive processing. Corticectomy had a greater effect than craniotomy alone, indicating a central trigger for hippocampal inflammatory changes. POCD after craniotomy may originate from a central inflammatory response resulting from surgical trauma to the brain parenchyma.

The Prevalence of Undiagnosed Presurgical Cognitive Impairment and Its Postsurgical Clinical Impact in Older Patients Undergoing Lumbar Spine Surgery

Objective

Because elderly patients are undergoing more surgeries, the importance of postoperative cognitive impairment (CI) evaluations is rising, especially for spine surgery, which is related to subjective pain. We investigated the prevalence of undiagnosed CI among elderly patients who underwent spine surgery and the impact of CI on postoperative outcomes.

Methods

The preoperative cognitive statuses of 129 patients over 65 who underwent lumbar spine surgery from 2012 to 2014 were determined with the Mini-Mental State Examination, and patients with scores under 24 were diagnosed with CI. The patients were then divided into a CI group (n=49) and non-cognitive impairment (NCI) group (n=80).

Results

Among the 129 patients, 49 (38.0%) were diagnosed with CI, and 9 (7.0%) had severe CI. The age of the CI group (72.88±6.20 years) was significantly greater than that of the NCI group (69.96±4.53 years). In contrast, the postoperative visual analog scale scores and performance statuses did not differ significantly. However, postoperative delirium was more frequent and the hospital stay length was longer in the CI group compared with the NCI group (p<0.05).

Conclusion

A high prevalence of undiagnosed CI was discovered among elderly patients undergoing spine surgery. The existence of CI was associated with higher rates of postoperative delirium and prolonged hospital stays, which affected clinical outcomes. Thus, CI assessments should be included in preoperative evaluations of elderly patients prior to spine surgery.

Risk Factors for Delirium After Spinal Surgery: A Meta-Analysis

OBJECTIVE

Postoperative delirium can occur following various types of surgeries. The specific risk factors for delirium following spinal surgery have not been systematically evaluated. The aim of this study is to conduct a meta-analysis of the risk factors for delirium after spinal surgery.

METHODS

PubMed, EMBASE, the Cochrane Library, and Science Citation Index were searched from inception to October 2014 for original research studies. Relevant studies on patients with delirium following spinal surgery were included if they identified at least 1 risk factor as being associated with delirium. The Newcastle-Ottawa Scale (NOS) was used for the study quality assessment, and the pooled odds ratios (ORs) were used for determining the risk factors.

RESULTS

Six articles met the inclusion criteria. Twenty-four risk factors in the multivariate analyses and 22 factors in the univariate analyses were significantly associated with delirium following spinal surgery. In the pooled analyses, age >65 years (OR: 6.13; 95% confidence interval [CI]: 5.75, 6.54); female sex (OR: 1.21; 95% CI: 1.15, 1.28); number of medications (mean difference [MD]: 1.36; 95% CI: 0.73, 2.00); low preoperative hematocrit (MD: -1.67; 95% CI: -2.97, -0.38) and albumin (MD: -0.33; 95% CI: -0.53, -0.13); duration of surgery (MD: 35.79; 95% CI: 1.42, 70.16); intraoperative blood loss (MD: 124.44; 95% CI: 100.03, 148.85); low postoperative hematocrit (MD: -2.58; 95% CI: -3.70, -1.46), hemoglobin (MD: -1.10; 95% CI: -1.86, -0.35), and sodium (MD: -2.97; 95% CI: -5.42, -0.51); and postoperative fever (OR: 4.52; 95% CI: 2.94, 6.95) were significantly associated with delirium.

CONCLUSIONS

Several risk factors were consistently associated with delirium following spinal surgery, which can be used to identify high-risk patients. Recognizing these patients is important for physicians to develop preventive strategies to reduce postoperative delirium and its negative consequences.