Postoperative delirium in elderly patients after major abdominal surgery

BACKGROUND: The aim of this study was to investigate the occurrence of postoperative delirium (POD) in elderly patients undergoing major abdominal surgery and to identify factors associated with delirium in this population. METHODS: Data were collected prospectively from 51 patients aged 65 years or more. Delirium was diagnosed by the Confusion Assessment Method and from the medical records. The Mini Mental State Examination (MMSE) was used to identify cognitive impairment. RESULTS: POD occurred in 26 of 51 patients. Delirium lasted for 1-2 days in 14 patients (short POD group) and 3 days or more in 12 patients (long POD group). The latter patients had significantly greater intraoperative blood loss and intravenous fluid infusion, a higher rate of postoperative complications, a lower MMSE score on postoperative day 4 and a longer hospital stay than patients without POD. Patients in the short POD group were significantly older than those in the long POD group and those who did not develop delirium. CONCLUSION: Approximately half of the elderly patients in this study developed POD. Bleeding was found to be an important risk factor for delirium.     

Randomized comparison between sevoflurane anaesthesia and unilateral spinal anaesthesia in elderly patients undergoing orthopaedic surgery

BACKGROUND AND OBJECTIVE: This prospective, randomized study was conducted to compare unilateral spinal block using small doses of hyperbaric bupivacaine and single-agent anaesthesia with sevoflurane in elderly patients undergoing hip surgery. METHODS: Thirty patients (> 65 yr) undergoing hip fracture repair were randomly allocated to receive unilateral spinal anaesthesia with hyperbaric bupivacaine 7.5 mg 0.5% (Group Spinal, n = 15) or volatile induction and maintenance anaesthesia with sevoflurane (Group SEVO, n = 15). General anaesthesia was induced by increasing the inspired concentration to 5%. A laryngeal mask airway was placed without muscle relaxants, and the end-tidal concentrations of sevoflurane were adjusted to maintain cardiovascular stability. Hypotension (decrease in systolic arterial pressure > 20% from baseline), hypertension or bradycardia (heart rate < 50 beats min(-1)) requiring treatment, and the length of stay in the postanaesthesia care unit was recorded. Cognitive functions were evaluated the previous day, and 1 and 7 days after surgery with the Mini Mental State Examination test. RESULTS: Hypotension occurred in seven patients of Group Spinal (46%) and in 12 patients of Group SEVO (80%) (P = 0.05). Phenylephrine was required to control hypotension in three spinal patients (21%) and four SEVO patients (26%) (n.s.). SEVO patients had lower heart rates than spinal patients from 15 to 60 min after anaesthesia induction (P = 0.01). Bradycardia was observed in three SEVO patients (22%). Discharge from the postanaesthesia care unit required 15 (range 5-30) min in Group Spinal and 55 (15-80) min in Group SEVO (P = 0.0005). Eight patients in Group Spinal (53%) and nine patients in Group SEVO (60%) showed cognitive decline (Mini Mental State Examination test decreased > or = 2 points from baseline) 24 h after surgery (n.s.). Seven days after surgery, confusion was still present in one patient of Group Spinal (6%) and in three patients of Group SEVO (20%) (n.s.). CONCLUSIONS: In elderly patients undergoing hemiarthroplasty of the hip, induction and maintenance with sevoflurane provide a rapid emergence from anaesthesia without more depression of postoperative cognitive function compared with unilateral spinal anaesthesia. This technique represents an attractive option when patient refusal, lack of adequate co-operation or concomitant anticoagulant therapy contraindicate the use of spinal anaesthesia.     

Postoperative analgesia and recovery course after major colorectal surgery in elderly patients: a randomized comparison between intrathecal morphine and intravenous PCA morphine

BACKGROUND AND OBJECTIVES: Intrathecal morphine is a widely used method for postoperative pain relief after major abdominal surgery. The aim of this randomized, double-blinded study was to compare intrathecal morphine and intravenous PCA morphine for postoperative analgesia and recovery course after major colorectal surgery in elderly patients. METHODS: After written informed consent, patients >70 years of age were prospectively and randomly assigned to receive either preoperative intrathecal morphine (0.3 mg) and postoperative patient-controlled (PCA) intravenous morphine (IT morphine) or PCA alone (group control). Results are presented as mean +/- SD (95% confidence interval). RESULTS: Twenty-six patients successfully completed the study in each group. In the IT morphine group, rate of awakening was delayed. Pain intensity and daily intravenous morphine consumption were significantly reduced 1 and 2 days after surgery in the IT morphine group (P < .01). Mental function (assessed by Mini Mental State and Digit Symbol Substitution Test) was similar in both groups. Episodes of postoperative delirium/confusion occurred similarly in both groups. Time to ileus resolution and time to ambulation without assistance did not differ between the 2 groups. The duration of hospitalization was 8.4 +/- 1.7 (7-11) days and 7.9 +/- 2.0 (6-9.9) days for control and IT morphine, respectively (nonstatistical difference). Patients in the IT morphine group had longer time to awakening from anesthesia and experienced more sedation. CONCLUSIONS: Intrathecal morphine, as compared with intravenous PCA morphine alone, improves immediate postoperative pain and reduces parenteral morphine consumption but does not improve postoperative recovery in elderly patients after major colorectal surgery.     

Induced arterial hypotension for interventional thoracic aortic stent-graft placement: impact on intracranial haemodynamics and cognitive function

BACKGROUND AND OBJECTIVE: The study investigated the impact of induced arterial hypotension for the facilitation of endovascular stent-graft placement in patients with thoracic aortic aneurysm on cerebral blood flow velocity and neurological/neurocognitive outcome. METHODS: In 27 ASA III patients, cerebral blood flow velocity was recorded during induced arterial hypotension for endovascular stent-graft placement using transcranial Doppler sonography and the Folstein Mini Mental State Examination and the National Institute of Health Stroke Scale were performed before and after the intervention. RESULTS: Mean arterial pressure was decreased <50 mmHg, and in 22 patients it was <40 mmHg. Diastolic cerebral blood flow velocity decreased by 59%. Postoperatively, six of 21 patients exhibited changes in the Folstein Mini Mental State Examination and four of these six patients in the National Institute of Health Stroke Scale as indices of new-found neurocognitive dysfunction, but there were no signs of stroke. Loss of the diastolic blood flow profile was detected in two of six patients with new-found neurocognitive dysfunctions and in 18 of 21 patients with no new-found neurocognitive dysfunction. Changes in the Folstein Mini Mental State Examination on postoperative day 1 were correlated to the pre-procedural Folstein Mini Mental State Examination, but not to the time spent with a mean arterial pressure <50 mmHg, <40 mmHg or with a loss of diastolic blood flow profile. CONCLUSIONS: Transcranial Doppler sonography visualizes the individual effect of induced hypotension and the period of intracranial circulatory arrest during aortic stent-graft placement. However, transient new-found neurocognitive dysfunctions occur independently of the transcranial Doppler data, and are in close correlation to the neurocognitive state before the procedure. The results suggest that induced arterial hypotension is not the major factor for postoperative new-found neurocognitive dysfunction.     

Cognitive impairment in patients with Fibromyalgia syndrome as assessed by the Mini-Mental State Examination

Background  

This study evaluated the frequency of cognitive impairment in patients with Fibromyalgia syndrome (FMS) using the Mini Mental State Examination (MMSE).     

Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery—2018

Cognitive change affecting patients after anaesthesia and surgery has been recognised for more than 100 yr. Research into cognitive change after anaesthesia and surgery accelerated in the 1980s when multiple studies utilised detailed neuropsychological testing for assessment of cognitive change after cardiac surgery. This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterwards. Importantly, other studies have identified that the incidence of cognitive change is similar after non-cardiac surgery. Other than the inclusion of non-surgical control groups to calculate postoperative cognitive dysfunction, research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the general population. The aim of this work is to develop similar terminology to that used in cognitive classifications of the general population for use in investigations of cognitive changes after anaesthesia and surgery. A multispecialty working group followed a modified Delphi procedure with no prespecified number of rounds comprised of three face-to-face meetings followed by online editing of draft versions.Two major classification guidelines [Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5) and National Institute for Aging and the Alzheimer Association (NIA-AA)] are used outside of anaesthesia and surgery, and may be useful for inclusion of biomarkers in research. For clinical purposes, it is recommended to use the DSM-5 nomenclature. The working group recommends that ‘perioperative neurocognitive disorders’ be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of acute event (postoperative delirium) and cognitive decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery) and up to 12 months (postoperative neurocognitive disorder).     

Age-related cognitive recovery after general anesthesia

This study was designed to quantify the rate of mental recovery in elderly and young patients after general anesthesia for intraabdominal surgery (cholecystectomy). Forty patients (25-83 yr) were given four tests assessing neuropsychological function once preoperatively and on five occasions postoperatively. Two of the four neuropsychological tests showed impairment in scores in the elderly patients on the first postoperative day (Symbol Digit Modalities Test, P less than 0.004; The Trail Making Test, P less than 0.03). In addition, one of the tests (Symbol Digit Modalities Test) showed a deterioration in the younger patients (P less than 0.05). The changes that did occur in these tests on the first postoperative day reverted to baseline levels thereafter. There were no significant changes in the remaining two tests, the Mini Mental State Test or the Digit Span Test, at any time in either group. We conclude that postoperative mental deterioration is no greater in elderly than in young patients.     

Monitoring cerebral oxygen saturation in elderly patients undergoing general abdominal surgery: a prospective cohort study

BACKGROUND AND OBJECTIVES: The aim of this prospective, observational study was to evaluate changes in regional cerebral oxygen saturation (rSO2) and incidence of intraoperative cerebral desaturation in a cohort of elderly patients undergoing major abdominal surgery. METHODS: rSO2 was continuously monitored on the left and right sides of the forehead in 60 patients older than 65 yr (35 males and 25 females; ASA II-III; age: 72 +/- 5 yr; without pre-existing cerebral pathology, and baseline Mini Mental State Examination (MMSE) score >23) undergoing sevoflurane anaesthesia for major abdominal, non-vascular surgery >2 h. RESULTS: Baseline rSO2 was 63 +/- 8%; cerebral desaturation (rSO2 decrease <75% of baseline or <80% in case of baseline rSO2 <50%) occurred in 16 patients (26%). The MMSE decreased from 28 +/- 1 before surgery to 27 +/- 2 on 7th postoperative day (P = 0.05). A decline in cognitive function (decrease in MMSE score > or = 2 points one week after surgery as compared to baseline value) was observed in six patients without intraoperative cerebral desaturation (13.6%) and six patients who had intraoperative cerebral desaturation (40%) (P = 0.057) (odds ratio: 4.22; CI95%: 1.1-16). Median (range) hospital stay was 14 (5-41) days in patients with an area under the curve of rSO2 <50% (AUCrSO2<50%) >10 min%, and 10 (4-30) days in those with an AUCrSO2<50% <10 min% (P = 0.0005). CONCLUSIONS: In a population of healthy elderly patients, undergoing non-vascular abdominal surgery cerebral desaturation can occur in up to one in every four patients, and the occurrence of cerebral desaturation is associated with a higher incidence of early postoperative cognitive decline and longer hospital stay.     

Postoperative delirium following gastrointestinal surgery in elderly patients

Postoperative delirium is a common complication which can interfere with the surgical treatment and recovery of elderly patients, and is likely to prolong their hospitalization. Unfortunately, there is as yet no completely effective pre- and/or post operative technique of patient care to reduce or prevent postoperative delirium. In this study, 36 patients aged over 70 years undergoing gastrointestinal operations were assessed to examine the relationships between the preoperative cognitive state, the postoperative sleep cycle, and the occurrence of postoperative delirium. All patients were evaluated preoperatively using the revised version of Hasegawa's dementia scale (HDS-R). We correlated those test results and assessed the sleep-wakefulness disturbance postoperatively, to obtain a clinical DMS-III diagnosis of postoperative delirium. The incidence of postoperative delirium was 17% (6/36). The patients who developed postoperative delirium demonstrated preoperative cognitive impairment, and had a short sleep period during the night and a long sleep period during the day. Postoperatively, these results suggest that HDS-R is a useful method of evaluating preoperative cognition in elderly patients. Considering that sleep deficiency is likely to predispose elderly patients to postoperative delirium, techniques to prevent sleep deprivation may be of considerable value in minimizing the incidence of postoperative delirium.     

A contrastive analysis of release patterns of biochemical markers of brain damage after coronary artery bypass grafting and valve replacement and their association with the neurobehavioral outcome after cardiac surgery.

OBJECTIVE: The present study aimed at a comparative analysis of neurobiochemical markers of brain damage and the neurobehavioral outcome in patients undergoing either valve replacement (VR) or isolated coronary artery bypass surgery (CABG). In order to control for well known risk factors both samples were strictly matched according to age, sex and preoperative neuropsychological performance. METHODS: We analysed neurone-specific enolase (NSE) and protein S-100B (S-100B) concentrations in serial venous blood samples taken preoperatively and 1, 6, 20 and 30 h postoperatively in 36 patients undergoing VR (N = 18) or isolated CABG surgery (N = 18). Mini Mental State Examination (MMS) was performed preoperatively, 3 and 7 days after surgery and 0.5 years later. Neuropsychiatric assessments were based on the diagnosis of postoperative delirium according to DMS-IIIR criteria and the Brief Psychiatric and the Delirium Rating Scale. RESULTS: VR and CABG patients, respectively, showed an increase of both S-100B (exact two-tailed Wilcoxon signed ranks test: P = 0.0001) and NSE (P = 0.0001) concentrations followed by a decrease during the next 30 h. Whereas S-100B values did not differ between patients groups subjects undergoing VR surgery exhibited higher NSE values during the postoperative course. Furthermore, VR patients showed a higher decline in cognitive performance which was also detectable 0.5 years after surgery. We found a weak association between the degree of individual postoperative decline of cognitive performance and S-100B area under curve values. CONCLUSIONS: Our data indicate that--apart from patients' age and preoperative neuropsychological performance--type of surgery remains a risk factor for postoperative neurobehavioral disorders. The different vulnerability of neurobehavioral disorders might be mirrored in different postoperative release patterns of NSE. We assume that both, NSE release and neurobehavioral disorders might be caused by a higher amount of intraoperative cerebral embolic events in VR patients.     

Anaesthesia for major orthopaedic surgery in the elderly

This article addresses three specific issues related to major hip and knee surgery in the elderly. Firstly, the importance of thorough pre-operative evaluation is discussed. Secondly, the pros and cons in the immediate peri-operative period of major regional (spinal or epidural) anaesthesia versus general anaesthesia are reviewed with respect to blood loss, cardiovascular and respiratory function and immunological and metabolic responses to surgery. Finally, the evidence for an anaesthetic technique effect on outcome parameters, especially thromboembolism, cognitive function and mortality, is presented. Regional anaesthesia is the method of choice for most patients undergoing elective hip surgery since it results in reduced blood loss and transfusion needs, modification of the neuro-endocrine stress response, improved early postoperative oxygenation, and a reduced incidence of deep vein thrombosis (DVT) postoperatively. In the surgery of fractures of the neck of femur, outcome with regional anaesthesia is at least comparable to that with general anaesthesia, but with improved early postoperative oxygenation and a smoother emergence from anaesthesia making initial nursing management easier. Comparative data in other forms of orthopaedic surgery in the elderly are few, but also support the use of regional techniques.     

Retrobulbar block fails to prevent an increase in serum cortisol concentration on emergence from anaesthesia after cataract surgery

We have studied 30 elderly patients undergoing cataract surgery,allocated randomly to receive general anaesthesia, local anaesthesiaby retrobulbar block or general anaesthesia combined with retrobulbarblock given after induction. Retrobulbar block alone preventedthe increases in circulating cortisol and glucose values whichoccurred in those patients receiving general anaesthesia alone.Retrobulbar block given after induction of general anaesthesia,however, suppressed the cortisol and glucose responses duringsurgery, but did not prevent a marked increase in cortisol concentrationsduring the immediate postoperative period. The results suggesta hormonal response to emergence from anaesthesia which hashitherto been masked by the stress response to surgery itself.(Br. J. Anaesth. 1994; 72: 119–121).     

Recovery of older patients undergoing ambulatory anaesthesia with isoflurane or sevoflurane

BACKGROUND: Delayed recovery of cognitive function is a well-recognized phenomenon in older patients. The potential for the volatile anaesthetic used to contribute to alterations in postoperative cognitive function in older patients following minor surgical procedures has not been determined. We compared emergence from isoflurane and sevoflurane anaesthesia in older surgical patients undergoing urological procedures of short duration. METHODS: Seventy-one patients, 60 yr of age or older, undergoing anaesthesia expected to last less than 60 min for ambulatory surgery, were randomly assigned to receive isoflurane or sevoflurane. A standardized anaesthetic protocol was used, with intravenous fentanyl 1 microg kg(-1) and propofol 1.5-2.0 mg kg(-1) administered to induce anaesthesia. Anaesthesia was maintained with either sevoflurane or isoflurane in 65% nitrous oxide and oxygen. Early and intermediate recovery times were recorded. The Mini Mental State Examination and digit repetition forwards and backwards were administered at baseline, and at 1, 3 and 6 h postoperatively, to assess cognitive function. RESULTS: There were no between-group differences in (sevoflurane vs. isoflurane, mean +/- standard error of the mean) times to removal of the laryngeal mask airway (7.7 +/- 0.6 vs. 7.1 +/- 0.4 min), verbal response time (10.1 +/- 0.7 vs. 9.9 +/- 0.7 min) and orientation (12.1 +/- 0.7 vs. 12.1 +/- 0.7 min). Intermediate recovery, as measured by time to readiness for discharge from the post anaesthesia care unit (44.9 +/- 1.5 vs. 44.3 +/- 1.5 min), was similar in the two groups. Postoperative indices of cognitive function and attention were comparably reduced at 1 h, but returned to baseline in both groups at 6 h. CONCLUSIONS: Isoflurane and sevoflurane anaesthesia resulted in similar clinical and neurocognitive recovery profiles in older patients undergoing ambulatory surgical procedures of short duration.     

Postoperative delirium after general anesthesia vs. spinal anesthesia in geriatric patients

BACKGROUND: Influence of the type of anesthesia on postoperative delirium was examined in geriatric patients with femoral neck fracture. METHODS: Forty patients aged 70 or more were randomly allocated to receive either general anesthesia (sevoflurane, nitrous oxide in oxygen, G group, n = 21) or spinal anesthesia (0.5% bupivacaine, S group, n = 19). G group received the oxygen therapy during the 12-hour postoperative period. Postoperative assessments included the rate of postoperative delirium during the 4-day postoperative period, oxygen saturation during the 18-hour postoperative period, the value of hemoglobin at 1 postoperative day and the number of analgesics requirements during the 4-day postoperative period. RESULTS: The rate of postoperative delirium was similar between the two groups during the 4-day postoperative period. However, that of S group tended to be higher during the 1-day postoperative period. Postoperative analgesic effect and the value of hemoglobin at 1 postoperative day were similar between the two groups. Oxygen saturation was similar between the two groups except 6 hours after the operation. CONCLUSIONS: The type of anesthesia, general or spinal, does not affect the postoperative delirium in geriatric patients with femoral neck fracture.     

区域阻滞麻醉与老年患者术后神经系统功能、病死率关系的研究进展

背景 区域阻滞麻醉应用于老年患者手术日益增多,其对老年患者术后神经系统功能、病死率的影响有待总结. 目的 通过文献综述,分析区域阻滞麻醉对老年患者术后神经系统、病死率的影响. 内容 讨论区域阻滞麻醉与老年患者术后神经系统功能,包括术后谵妄、认知功能障碍、脑卒中以及与病死率之间的关系. 趋向 区域阻滞麻醉可以减少老年患者术后肺部并发症,减少术后早期认知功能障碍,与全身麻醉相比,具有一定优势.区域阻滞麻醉是否能降低老年患者术后病死率、心血管并发症发生率、谵妄发生率、围手术期脑卒中发生率尚有待于进一步研究.     

Acute postoperative confusional syndrome in the elderly patient

With the progressive aging of the population surgical candidates have more comorbidities resulting in a higher risk to develop postoperative complications. One of the most frequent postoperative complications in the elderly is acute confusional state or delirium, which may have devastating consequences: higher mortality, and risk of medical complications during admission and, a higher risk of functional decline, institutionalization, and cognitive impairment at discharge. For all these reasons and with the aim of optimising surgical procedures, it is essential to identify patients at risk of delirium in order to take appropriate preventive action and provide early treatment. In the present article we review the current evidence on the management of postoperative delirium in the elderly.     

Postoperative oxygenation in the elderly following general or local anaesthesia for ophthalmic surgery

Peripheral oxygen saturation was recorded on the pre-operative night (between 2400 and 0600 h), the immediate postoperative period (first 60 min) and the first postoperative night (2400 to 0600 h) in 18 elderly patients aged 70 years or over presenting for elective ophthalmic surgery. Nine patients had surgery performed under general anaesthesia employing muscle relaxants and controlled ventilation and nine under local anaesthesia using a peribulbar block. The median (interquartile range) percentage of time during which the patients had an oxygen saturation of less than 90% was 0 (0-0.2) and 0.04 (0-0.4) on the pre-operative night, 0.7 (0-1.4) and 0.3 (0-1.2) in the immediate postoperative period, and 0.05 (0-0.16) and 0 (0-0.3) on the postoperative night in the general and local anaesthesia patients respectively. There were no significant differences between general and local anaesthesia in respect of these data and the overall incidence of significant desaturation was low. The present study could not demonstrate any adverse effect of general anaesthesia on oxygen saturation in patients undergoing minimally invasive surgery.     

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。     

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.     

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.