Risk factors and prevalence of perioperative cognitive dysfunction in abdominal aneurysm patients

BACKGROUND: Perioperative delirium is common in high-risk surgery and is associated with age, education, preoperative cognitive functioning, pre-existing medical conditions, and postoperative complications. We investigated these factors as well as lifestyle and demographic variables by using cognitive measures that were more sensitive than those used in previous studies. METHODS: Extensive medical and demographic data were collected on 102 patients between 41 and 88 years of age to identify comorbidities and lifestyle considerations preoperatively. Elective abdominal aortic aneurysm surgery was performed under combined general/epidural anesthesia with postoperative epidural analgesia. A battery of sensitive, cognitive measures was administered preoperatively, at the time of discharge from hospital, and 3 months postoperatively. Symptoms of delirium were assessed during the first 6 postoperative days using Diagnostic and Statistical Manual of Mental Disorders-4th Edition criteria. Intraoperative and postoperative data, including medications, vital signs, conduct of the surgery and anesthesia, complications, and details of pain control, were collected. RESULTS: Delirium occurred in 33% of the patients during the first 6 days after surgery. Longer duration of delirium was related to lower education, preoperative depression, and greater preoperative psychoactive medication use. Characteristics of the surgery and hospital stay were unrelated to the development of delirium. Patients who were diagnosed with delirium had lower cognitive scores during each of the three assessment periods, even when controlling for age and education. Logistic regression analysis indicated that the most powerful preoperative predictors of delirium were number of pack years smoked (P = .001), mental status scores (P = .003), and number of psychoactive medications (P = .005). CONCLUSION: A significant proportion of patients undergoing elective abdominal aortic aneurysm repair are susceptible to the development of delirium and are at risk for cognitive dysfunction after surgery. Our findings have implications for promoting long-term lifestyle changes, including smoking cessation and improved management of mental health as risk-reduction strategies.     

Postoperative delirium in spine surgery.

BACKGROUND CONTEXT: Postoperative delirium is a great concern in the treatment of hip fracture. However, there have been no reports regarding the postoperative delirium in spine surgery. PURPOSE: To determine the incidence and risk factors for postoperative delirium in the patients who have had spine surgery. STUDY DESIGN/SETTING: The incidence and intraoperative risk factors of postoperative delirium were retrospectively examined in patients who had spine surgery during a 3-year period. PATIENT SAMPLE: Three hundred forty-one patients who underwent spine surgery from 2000 to 2002 were included. METHODS: The presence of delirium was determened by the Confusion Assessment Method. Laboratory data were checked preoperatively, at 1 day and 1 week postoperatively. The prognosis of postoperative delirium was evaluated. RESULTS: Postoperative delirium was found in 13 patients; all of them were in their 70's or 80's. The incidence of delirium was 12.5% in the patients over 70 years old. Hemoglobin and hematocrit levels at 1 day after surgery in the delirium group were significantly lower than those in the control group. One patient had persistent cognitive dysfunction after surgery. Two patients who developed postoperative delirium died during the follow-up period. CONCLUSION: Low concentrations of hemoglobin and hematocrit 1 day after surgery were risk factors for postoperative delirium. As delirium is thought to represent not only brain dysfunction, but also impaired general physical condition, careful observation is necessary for the management of patients with postoperative delirium.     

Central nervous system dysfunction after anesthesia in the geriatric patient

Cerebral infarction, bleeding, long-lasting hypofusion, and profound hypoxia are well-known factors behind central nervous system dysfunction after anesthesia. Other explanations may be the metabolic-endocrine stress response and psychologic factors related to changes in the environment. The clinical presentations can be obvious as in cerebral death or stroke but delirium also may be readily recognized. A more subtle and long-lasting deterioration in cognitive function is called postoperative cognitive dysfunction. This condition can only be detected with the use of neuropsychologic testing and recently, postoperative cognitive dysfunction has been detected as the most common cerebral complication after noncardiac surgery in elderly patients.     

Distúrbios cognitivos adversos no pós‐operatório: uma pesquisa nacional de anestesiologistas portugueses

Background and objectives

Postoperative delirium and postoperative cognitive dysfunction are some of the most common complications in older surgical patients and are associated with adverse outcomes. The aim of this study was to evaluate portuguese anesthesiologists’ perspectives and knowledge about adverse postoperative cognitive disorders, and routine clinical practice when caring for older surgical patients.

Predictors of delirium after cardiac surgery delirium: effect of beating-heart (off-pump) surgery

BACKGROUND: Despite improved outcomes after cardiac operations, postoperative delirium remains a common complication that is associated with increased morbidity and prolonged hospital stay. METHODS: Univariate and multivariate predictors of postoperative delirium were determined from prospectively gathered data on 16,184 patients undergoing cardiac operations with cardiopulmonary bypass (conventional, n = 14,342) and without cardiopulmonary bypass (beating-heart surgery, n = 1847) between April 1996 and August 2001. Delirium was defined as a transient mental syndrome of acute onset characterized by global impairment of cognitive functions, a reduced level of consciousness, attentional abnormalities, increased or decreased psychomotor activity, and a disordered sleep-wake cycle. RESULTS: The overall prevalence of postoperative delirium was 8.4%. Of 49 selected patient-related risk factors and treatment variables, 35 were highly associated with postoperative delirium by univariate analysis. Stepwise logistic regression revealed the following variables as independent predictors of delirium: history of cerebrovascular disease, peripheral vascular disease, atrial fibrillation, diabetes mellitus, left ventricular ejection fraction of 30% or less, preoperative cardiogenic shock, urgent operation, intraoperative hemofiltration, operation time of 3 hours or more, and a high perioperative transfusion requirement. Two variables were identified as having a significant protective effect against postoperative delirium: beating-heart surgery and younger patient age. CONCLUSIONS: Postoperative delirium is a common complication in cardiac operations. The increased use of beating-heart surgery without cardiopulmonary bypass may lead to a lower prevalence of this complication and thus improve patient outcomes.     

术后谵妄：具有远期作用的急性改变

谵妄是一种认知力和注意力的急性改变,包括意识改变和思维涣散。尽管谵妄可以出现于任何年龄组的患者,但是最常见于老年患者,尤其是那些已存在认知功能障碍的老年患者。术后谵妄的患者较无谵妄的患者恢复慢,因此增加了住院时间和医疗费用。术后谵妄的发生率与手术类型、手术紧迫性和谵妄评估方法的类型及敏感性有关。尽管谵妄通常被认为是一种短期病变,其实它可以持续数月并且与术后中期认知功能不良有关。本文中,我们给出了指南对谵妄这一常见的病理状态风险进行术前评估及预防、诊断和治疗。提高诊疗水平,例如术前明确谵妄发生的风险;训练外科医生、麻醉医生和护士诊断谵妄的能力;实行谵妄预防计划以及制定谵妄治疗的标准流程可能有助于减少谵妄及其相关发病率。     

Postoperative Störungen der kognitiven Leistungsfähigkeit bei älteren Patienten Die Ergebnisse der „International Study of Postoperative Cognitive Dysfunction” (ISPOCD 1)

OBJECTIVE: Cognitive dysfunction is a known problem after operations and may be especially relevant in the elderly. The aim of this international multicentre study was to investigate short- and long-term cognitive dysfunction in elderly patients and to elucidate the relevance of hypoxaemia and hypotension as causative factors. METHODS: 1218 patients aged 60 years and older and scheduled for major non-cardiac surgery under general anaesthesia were investigated. Oxygen saturation was measured by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. Blood pressure was recorded every 3 minutes during the operation and every 15-30 min for the rest of that day and night. Cognitive testing was performed before and 1 week and 3 months after the operation. Cognitive dysfunction was identified with neuropsychological tests compared with controls recruited from the UK (n = 176) and the same countries as study centres (n = 145). RESULTS: Postoperative cognitive dysfunction was present in 25.8% of patients 1 week after surgery and in 9.9% 3 months after surgery, compared with 3.4% and 2.8%, respectively, of the UK controls. Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were the risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for long-term postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time. CONCLUSION: With this investigation long-term cognitive dysfunction could be proven definitively for elderly patients after major operations under general anaesthesia. No factors with prophylactic or therapeutic influence were detectable so that aetiology and pathophysiology of POCD could not be further determined.     

Review articles: postoperative delirium: acute change with long-term implications

Delirium is an acute change in cognition and attention, which may include alterations in consciousness and disorganized thinking. Although delirium may affect any age group, it is most common in older patients, especially those with preexisting cognitive impairment. Patients with delirium after surgery recover more slowly than those without delirium and, as a result, have increased length of stay and hospital costs. The measured incidence of postoperative delirium varies with the type of surgery, the urgency of surgery, and the type and sensitivity of the delirium assessment. Although generally considered a short-term condition, delirium can persist for months and is associated with poor cognitive and functional outcomes beyond the immediate postoperative period. In this article, we provide a guide to assess delirium risk preoperatively and to prevent, diagnose, and treat this common and morbid condition. Care improvements such as identifying delirium risk preoperatively; training surgeons, anesthesiologists, and nurses to screen for delirium; implementing delirium prevention programs; and developing standardized delirium treatment protocols may reduce the risk of delirium and its associated morbidity.     

Can we identify risk factors for postoperative delirium in cardiac coronary patients? Our experience

Introduction: Delirium is a temporary mental disorder that frequently occurs among elderly hospitalized patients. Patients who undergo cardiac operations have an increased risk of postoperative delirium, which is associated with higher mortality and morbidity rates, a prolonged hospital stay, and reduced cognitive and functional recovery.Patients and Methods: In our prospective study, we included 370 consecutive adult patients who underwent on-pump coronary artery surgery between January 1, 2011, and July 1, 2011. We selected 21 potential risk factors and divided them into preoperative, intraoperative, and postoperative groups. Delirium was diagnosed with the Confusion Assessment Method.Results: Postoperative delirium was diagnosed in 74 patients (20%). Four predictive factors were associated with postoperative delirium: diabetes mellitus, cerebrovascular disease, peripheral vascular disease, and prolonged intubation (P < .05).Conclusion: Three of the four predictive factors significantly associated with delirium are preoperative. They are relatively easy to measure and can be used to identify patients at higher risk. Fast extubation of these patients and preventive interventions can be taken to prevent negative consequences of this postoperative complication.     

Cognitive dysfunction 1-2 years after non-cardiac surgery in the elderly. ISPOCD group. International Study of Post-Operative Cognitive Dysfunction

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a well-recognised complication of cardiac surgery, but evidence of POCD after general surgery has been lacking. We recently showed that POCD was present in 9.9% of elderly patients 3 months after major non-cardiac surgery. The aim of the present study was to investigate whether POCD persists for 1-2 years after operation. METHODS: A total of 336 elderly patients (median age 69 years, range 60-86) was studied after major surgery under general anesthesia. Psychometric testing was performed before surgery and at a median of 7, 98 and 532 days postoperatively using a neuropsychological test battery with 7 subtests. A control group of 47 non-hospitalised volunteers of similar age were tested with the test battery at the same intervals. RESULTS: 1-2 years after surgery, 35 out of 336 patients (10.4%, CI: 7.2-13.7%) had cognitive dysfunction. Three patients had POCD at all three postoperative test sessions (0.9%). From our definition of POCD, there is only a 1:64000 likelihood that a single subject would have POCD at all three test points by chance. Logistic regression analysis identified age, early POCD, and infection within the first three postoperative months as significant risk factors for long-term cognitive dysfunction. Five of 47 normal controls fulfilled the criteria for cognitive dysfunction 1-2 years after initial testing (10.6%, CI: 1.8-19.4%), i.e. a similar incidence of age-related cognitive impairment as among patients. CONCLUSION: POCD is a reversible condition in the majority of cases but may persist in approximately 1% of patients.     

Cerebral dysfunction after coronary artery bypass surgery

Cerebral dysfunction after cardiac surgery remains a devastating complication and is growing in importance with our aging populations. Neurological complications following cardiac surgery can be classified broadly as stroke, encephalopathy (including delirium), or postoperative cognitive dysfunction (POCD). These etiologies are caused primary by cerebral emboli, hypoperfusion, or inflammation that has largely been attributed to the use of cardiopulmonary bypass. Preventative operative strategies, such as off-pump coronary artery bypass grafting (CABG), can potentially reduce the incidence of postoperative neurological complications by avoiding manipulation of the ascending aorta. Although off-pump CABG is associated with reduced risk of stroke, there are no convincing differences in POCD between off-pump and on-pump CABG. Recently, the focus of postoperative neurological research has shifted from managing cardiopulmonary bypass to patient-related factors. Identifying changes in brains of aged individuals undergoing cardiac surgery may improve strategies for preventing cerebral dysfunction. Advanced age is associated with more undiagnosed cerebrovascular disease and is a major risk factor for stroke and POCD following cardiac surgery. Preoperative cerebrovascular evaluation and adaptation of surgical strategies will provide preventative approaches for cerebral dysfunction after CABG. This review focuses on recent findings of the relationship between perioperative stress and underlying fragility of the brain in cardiac surgical patients.     

Improved perioperative neurological monitoring of coronary artery bypass graft patients reduces the incidence of postoperative delirium: the Haga Brain Care Strategy

OBJECTIVES Postoperative delirium is a major cause of morbidity and mortality after cardiovascular surgery. Risk factors for postoperative delirium include poor cerebral haemodynamics and perioperative cerebral desaturations. Our aim was to reduce the postoperative delirium rate by using a new prevention strategy called the Haga Brain Care Strategy. This study evaluates the efficacy of the implementation of the Haga Brain Care Strategy to reduce the postoperative delirium rate after elective coronary artery bypass graft (CABG) procedures. The primary endpoint was the postoperative delirium rate, and the secondary endpoint was the length of stay in the intensive care unit. METHODS The Haga Brain Care Strategy consisted of the conventional screening protocol for delirium with the addition of preoperative transcranial Doppler examinations, perioperative cerebral oximetry, modified Rankin score, delirium risk score and (if indicated) duplex examination of the carotid arteries. In case of poor preoperative haemodynamics, the cerebral blood flow was optionally optimized by angioplasty or the patient was operated on under mild hypothermic conditions. Perioperative cerebral desaturations >20% outside the normal range resulted in intervention to restore cerebral oxygenation. Cerebral oximetry was discontinued when patients regained consciousness. Patients undergoing elective CABG procedures in 2010 were compared with patients scheduled for coronary bypass graft procedures in 2009 who had not been exposed to additional Haga Brain Care Strategy assessment. RESULTS A total of 233 and 409 patients were included in 2009 and 2010, respectively. The number of patients subjected in 2010 to transcranial Doppler examinations, cerebral oximetry or both (Haga Brain Care Strategy) were 262 (64.1%), 201 (49.1%) and 139 (34.0%), respectively. The overall rate of postoperative delirium decreased from 31 (13.3%) in 2009 to 30 (7.3%) in 2010 (P?=?0.019). A binary logistic regression model showed that the Haga Brain Care Strategy was an independent predictor of a reduced risk of developing a postoperative delirium (odd ratio?=?0.37, P?=?0.021). CONCLUSIONS With the implementation of the Haga Brain Care Strategy in 2010, a reduction of the incidence of postoperative delirium in patients undergoing elective CABG procedures was observed. In addition, the length of stay in the intensive care unit showed an overall tendency to decline. The limited number of observations and the current study design do not allow a full evaluation of the Haga Brain Care Strategy but the data support the idea that a sophisticated preoperative assessment of cerebral haemodynamics and perioperative monitoring of cerebral oximetry reduce the incidence of the postoperative delirium in CABG surgery.     

Delirium is associated with early postoperative cognitive dysfunction

The purpose of this analysis was to determine if postoperative delirium was associated with early postoperative cognitive dysfunction (at 7 days) and long-term postoperative cognitive dysfunction (at 3 months). The International Study of Postoperative Cognitive Dysfunction recruited 1218 subjects ≥ 60 years old undergoing elective, non-cardiac surgery. Postoperatively, subjects were evaluated for delirium using the criteria of the Diagnostic and Statistical Manual. Subjects underwent neuropsychological testing pre-operatively and postoperatively at 7 days ( n  = 1018) and 3 months ( n  = 946). Postoperative cognitive dysfunction was defined as a composite Z -score > 2 across tests or at least two individual test Z -scores > 2. Subjects with delirium were significantly less likely to participate in postoperative testing. Delirium was associated with an increased incidence of early postoperative cognitive dysfunction (adjusted risk ratio 1.6, 95% CI 1.1–2.1), but not long-term postoperative cognitive dysfunction (adjusted risk ratio 1.3, 95% CI 0.6–2.4). Delirium was associated with early postoperative cognitive dysfunction, but the relationship of delirium to long-term postoperative cognitive dysfunction remains unclear.     

Predicting delirium after vascular surgery: a model based on pre- and intraoperative data

OBJECTIVE: The aim of the study was to determine pre- and intraoperative risk factors for the development of postoperative delirium among patients undergoing aortic, carotid, and peripheral vascular surgery to predict the risk for postoperative delirium. SUMMARY BACKGROUND DATA: Although postoperative delirium after vascular surgery is a frequent complication and is associated with the need for more inpatient hospital care and longer length of hospital stay, little is known about risk factors for delirium in patients undergoing vascular surgery. METHODS: Pre-, intra-, and postoperative data were prospectively collected, including the first 7 postoperative days with daily follow-up by a surgeon and a psychiatrist of 153 patients undergoing elective vascular surgery. Delirium (Diagnostic and statistical Manual of Mental Disorders IV) was diagnosed by the psychiatrist. Multivariate linear logistic regression and a cross validation analysis were performed to find a set of parameters to predict postoperative delirium. RESULTS: Sixty patients (39.2%) developed postoperative delirium. The best set of predictors included the absence of supraaortic occlusive disease and hypercholesterinemia, history of a major amputation, age over 65 years, a body size of less than 170 cm, preoperative psychiatric parameters and intraoperative parameters correlated to increased blood loss. The combination of these parameters allows the estimation of an individual patients' risk for postoperative delirium already at the end of vascular surgery with an overall accuracy of 69.9%. CONCLUSIONS: Postoperative delirium after vascular surgery is a frequent complication. A model based on pre- and intraoperative somatic and psychiatric risk factors allows prediction of the patient's risk for developing postoperative delirium.     

老年患者脊柱手术术后谵妄危险因素分析的回顾性研究

目的:探讨老年患者脊柱手术术后谵妄的发生率及相关危险因素。方法:采用回顾性分析2016年1月至2018年11月收治的老年脊柱手术病例436例,根据术后是否发生谵妄分为谵妄组和非谵妄组。记录患者的性别、年龄、身体质量指数,糖尿病史,冠心病史,慢性阻塞性肺疾病史,术前白细胞计数,术前红细胞比容,术前血红蛋白水平,手术方式,手术时间,麻醉时间,美国麻醉医师协会(ASA)评分,心功能分级,术中失血量,术中输血量,术中芬太尼、异丙酚和地佐辛的用量,术后白细胞计数,术后红细胞比容,术后血红蛋白水平,术后电解质(钠离子、钾离子),采用单因素Logistic回归分析有统计学意义的危险因素后进行多元Logistic回归分析进一步探讨独立危险因素。结果:纳入436例中112例老年患者术后出现谵妄,发生率25.68%。谵妄组与非谵妄组在年龄、术前白细胞计数、术前红细胞比容、术后红细胞比容、术后血红蛋白水平、术后钠离子浓度、麻醉时间、ASA评分、心功能评分、术中失血量、术后地佐辛使用量、糖尿病史、冠心病史、慢性阻塞性肺疾病史方面差异有统计学意义(P0.05),通过多因素Logistic回归分析显示年龄、ASA评分、术后地佐辛量、慢性阻塞性肺疾病史是老年患者脊柱手术术后谵妄发生的独立危险因素。结论:患者高龄72岁、ASA评分2分、地佐辛镇痛药物的使用以及患者合并慢性阻塞性肺疾病史是术后谵妄发生的独立危险因素。     

Postoperative hyperperfusion syndrome in elderly patients with chronic subdural hematoma

BACKGROUND: Temporary acute agitated delirium is a frequent complication after surgery for chronic subdural hematoma (CSH) in elderly patients. To clarify the pathogenic mechanism underlying this complication, we measured cerebral blood flow before and after surgery in elderly patients with CSHs. METHODS: Twenty-seven patients aged 75 years or older with unilateral CSH underwent treatment involving a single burr hole craniostomy with continuous catheter drainage. Cerebral blood flow was measured using single photon emission computed tomography 1 day before surgery, and at 1 hour and 24 hours after surgery. Acute agitated delirium was diagnosed by the characteristic behavioral abnormality. RESULTS: SPECT imaging 1 hour after surgery demonstrated hyperperfusion in the cerebral cortex beneath the CSH in 14 patients (51.9%). Of these 14 patients, five showed acute agitated delirium a few hours after surgery that persisted for 10 to 12 hours. A hematoma was detected in the right hemisphere in all five patients. Hyperperfusion was significantly more intense in patients with acute agitated delirium both 1 hour and 24 hours after surgery than in patients (n = 9) without acute agitated delirium. Moreover, mean arterial blood pressure during the first postoperative hour was significantly higher in patients with acute agitated delirium. CONCLUSION: In elderly patients with CSH, intense and prolonged hyperperfusion after surgery induces temporary acute agitated delirium. This postoperative hyperperfusion syndrome is exacerbated by hypertension.     

Preoperative factors associated with postoperative change in confusion assessment method score in hip fracture patients

Postoperative delirium is a major problem in elderly patients undergoing surgical repair of hip fracture. It is imperative to identify potentially treatable preoperative factors associated with the onset of postoperative delirium to optimize outcome. We sought to determine what preoperative variables are associated with postoperative delirium in geriatric patients undergoing surgical repair of hip fracture. In a prospective, IRB-approved study, patients admitted to the geriatric hip fracture service were examined daily in the hospital for the occurrence of postoperative delirium. All patients with a preoperative diagnosis of dementia or delirium were eliminated. A positive confusion assessment method score ([+]CAM) was used to determine the presence of postoperative delirium during the acute hospital stay. To determine the association between preoperative variables (demographics, laboratory values, and comorbidities) and postoperative (+)CAM scores, chi(2) and logistic regression analysis were performed with calculation for the odds ratios (OR). One-hundred-sixty-eight patients (72% women) were included in the analysis. Twenty-eight percent (n = 47) of patients had a (+)CAM score. Three variables were significant predictors of a (+)CAM score: (a) normal white blood cell count (OR, 2.2), (b) abnormal serum sodium (OR, 2.4); and (c) ASA physical status >II (OR, 11.3). The results suggest that preoperative medical conditions (abnormal serum sodium and ASA physical status >II) and an inability to mount a stress response (normal white blood cell count) may influence the patient's postoperative mental status. In particular, two of the risk factors we identified may be amenable to therapy and are abnormal serum sodium and lack of an increase in white blood cell count during the stress of trauma and surgery. IMPLICATIONS: This prospective study investigated preoperative variables that are predictive of postoperative delirium in geriatric patients undergoing surgical repair of hip fracture. The results suggest that the patient's preoperative medical condition and inability to mount a stress response influence postoperative delirium.     

非心脏手术患者术后谵妄的危险因素

目的 筛选非心脏手术患者发生术后谵妄的危险因素.方法 择期围术期有可疑危险因素的非心脏手术患者480例,年龄18～92岁,根据术后3 d内是否发生谵妄分为术后谵妄组和非术后谵妄组.可疑危险因素进行组间比较后,将差异有统计学意义的因素进行logistic回归分析,筛选发生术后谵妄的危险因素.结果 79例术后发生谵妄,发生率为16.5%.logistic回归分析结果显示,老龄、全身麻醉、手术时间≥3 h、术后Price-Henry疼痛评分为4分、合并肺气肿、饮酒≥3次/周是发生术后谵妄的独立危险因素(P＜0.05),相对危险度依次为1.924、0.188、2.251、1.752、18.954、1.779.结论 老龄、全身麻醉、长时间手术、术后剧烈疼痛、合并肺气肿、长期饮酒是非心脏手术患者发生术后谵妄的危险因素.     

Development and validation of a risk score for predicting postoperative delirium after major abdominal surgery by incorporating preoperative risk factors and surgical Apgar score

Study objectiveTo develop and validate a simple delirium-predicting scoring system in patients undergoing major abdominal surgery by incorporating preoperative risk factors and intraoperative surgical Apgar score (SAS).DesignObservational retrospective cohort study.SettingA tertiary general hospital in China.Patients1055 patients who received major abdominal surgery from January 2015 to December 2019.MeasurementsWe collected data on preoperative and intraoperative variables, and postoperative delirium. A risk scoring system for postoperative delirium in patients after major open abdominal surgery was developed and validated based on traditional logistic regression model. The elastic net algorithm was further developed and evaluated.Main resultsThe incidence of postoperative delirium was 17.8% (188/1055) in these patients. They were randomly divided into the development (n = 713) and validation (n = 342) cohorts. Both the logistic regression model and the elastic net regression model identified that advanced age, arrythmia, hypoalbuminemia, coagulation dysfunction, mental illness or cognitive impairments and low surgical Apgar score are related with increased risk of postoperative delirium. The elastic net algorithm has an area under the receiver operating characteristic curve (AUROC) of 0.842 and 0.822 in the development and validation cohorts, respectively. A prognostic score was calculated using the following formula: Prognostic score = Age classification (0 to 3 points) + arrythmia + 2 * hypoalbuminemia + 2 * coagulation dysfunction + 4 * mental illness or cognitive impairments + (10-surgical Apgar score). The 22-point risk scoring system had good discrimination and calibration with an AUROC of 0.823 and 0.834, and a non-significant Hosmer-Lemeshow test P = 0.317 and P = 0.853 in the development and validation cohorts, respectively. The bootstrapping internal verification method (R = 1000) yielded a C-index of 0.822 (95% CI: 0.759–0.857).ConclusionThe prognostic scoring system, which used both preoperative risk factors and surgical Apgar score, serves as a good first step toward a clinically useful predictive model for postoperative delirium in patients undergoing major open abdominal surgery.     

Predictive nomogram for postoperative delirium in elderly patients with a hip fracture

To evaluate the risk factors for the development of postoperative delirium and design a predictive nomogram for the prevention of delirium in elderly patients with a hip fracture, we retrospectively studied 825 patients who sustained a femoral neck fracture from January 2005 to December 2015. Independent risk factors for developing delirium within 6 months of surgery were identified using multivariable logistic regression analyses. A predictive nomogram model was built based on the results, and the discrimination and calibration were determined by C-index and calibration plot. Of the 825 patients who met inclusion criteria, 118 (14.3%) developed postoperative delirium. According to the results, preoperative cognitive impairment (OR, 4.132, 95% CI, 1.831 to 9.324, P＜0.001), multiple medical comorbidities (OR, 1.452, 95% CI, 0.958–2.202, P?=?0.079), ASA classification (OR, 1.655, 95% CI, 1.073–2.553, P?=?0.023), transfusion exceeding 2 units of red blood cell (OR, 1.599, 95% CI, 1.043–2.451, P?=?0.035), and intensive care (OR, 1.817, 95% CI, 1.127–2.930, P?=?0.014) were identified to be the independent predictors of the development of postoperative delirium. The risk of postoperative delirium increased with the increasing risk score of predictive nomogram, and the C-index was 0.67 (0.62 - 0.72). The calibration showed that the predicted probabilities of delirium in the predictive nomogram were close to the observed frequency of delirium, and the decision curve analysis confirmed the clinical utility of the nomogram when the threshold probabilities were between 8% and 35% due to the net benefit.