The impact of the type of anaesthesia on cognitive status and delirium during the first postoperative days in elderly patients

BACKGROUND AND OBJECTIVES: Postoperative confusion and delirium is a common complication in the elderly with a poorly understood pathophysiology. The aim of this study was to examine whether the type of anaesthesia (general or regional) plays a role in the development of cognitive impairment in elderly patients during the immediate postoperative period. METHODS: Forty-seven patients > 60 yr of age and undergoing major surgery were randomly allocated to receive either regional or general anaesthesia. The mental status of the patients was assessed preoperatively and during the first three postoperative days with the Mini Mental State Examination. The incidence of delirium was also examined during the same period with the use of DSM III criteria. RESULTS: Overall, during the first three postoperative days, the mean Mini Mental State Examination score decreased significantly (P < 0.001). However, this decline was very significant only in patients assigned to receive general anaesthesia (P < 0.001) compared to regional anaesthesia. Nine patients developed delirium but the type of anaesthesia did not affect its incidence. The only important factor for the development of delirium was preexisting cardiovascular disease irrespective of anaesthesia type (P < 0.025). CONCLUSIONS: Elderly patients subjected to general anaesthesia displayed more frequent cognitive impairment during the immediate postoperative period in comparison to those who received a regional technique.     

良性前列腺增生患者术后谵妄的临床分析

目的:探讨良性前列腺增生(BPH)患者术后发生谵妄的影响因素。方法:分析我院198例60～83岁BPH手术患者的年龄与术后疼痛、低氧血症和睡眠时间减少发生的关系,判定患者术后发生谵妄的危险因素。结果:198例患者术后发生谵妄13例(6.5%),≥70岁的患者与<70岁患者相比,术后谵妄发生率增加(1.6%vs14%,P<0.05)。结论:高龄患者前列腺术后疼痛和睡眠障碍是发生谵妄的重要原因,镇痛及良好的睡眠对预防术后谵妄有积极的意义。     

Recovery room delirium predicts postoperative delirium after hip-fracture repair

In this study, we sought to determine the incidence of recovery room delirium in elderly patients having hip-fracture repair under general anesthesia and to discover whether recovery room delirium is associated with continuing postoperative delirium. In this prospective study, patients undergoing hip-fracture repair were anesthetized using a standardized protocol. In addition, postoperative pain management was standardized in both the postoperative anesthesia care unit and in the hospital ward. The presence of delirium was determined using the confusion assessment method (CAM) score. Recovery room delirium was assessed by obtaining a CAM score at 60 min after discontinuation of isoflurane. Postoperative delirium was assessed by obtaining a daily CAM score during the postoperative in-hospital recovery period. Fifty patients consented to the study and 47 patients were included in the analysis (surgery cancelled postinduction n = 1; nonadherence to protocol n = 2). Average patient age was 77 +/- 1 (mean +/- SE) yr (range, 56-98 yr). Seventy-seven percent of the study patients were ASA class III or more. The prevalence of recovery room delirium was 45%. The prevalence of postoperative delirium was 36%. Recovery room delirium predicted postoperative delirium (P < 0.001, Fisher's exact test) with a sensitivity of 100% and a specificity of 85%. Analgesic doses administered in the postoperative anesthesia care unit and ward were similar in patients with or without postoperative delirium. Results of this study show that recovery room delirium is a strong predictor of postoperative delirium. IMPLICATIONS: In patients undergoing hip-fracture repair, recovery room delirium is a strong predictor of postoperative delirium when using a standardized protocol for general anesthesia and postoperative pain management.     

Postoperative cognitive disorders in the elderly

TWO DISTINCT CATEGORIES: Postoperative cognitive disorders include delirium and long-term cognitive dysfunction. DELERIUM: Delirium is an acute state occurring early during the postoperative period. It may be considered as an acute cerebral insufficiency which may be consecutive both to the negative effects of aging and chronic illness on cognitive function, and to the cerebral impact of operative stress. In addition, precipitating postoperative medical factors may facilitate cerebral failure. Only a few studies have been devoted to prevention programs aimed at reducing the risk of postoperative delirium. Nevertheless, we can hypothesize that a preoperative gerontology assessment would be effective in determining risk factors of delirium in old patients and thus enable proposing individual postoperative management. LONG-TERM COGNITIVE DYSFUNCTION: The definition of this clinical picture is less precise than delirium. Long-term cognitive dysfunction corresponds to a loss of cognitive performance in the weeks and months after anesthesia. The IPOCD1 study conducted in a large cohort of elderly patients has shown that postoperative cognitive dysfunction was present in 25.8% of patients 1 week after surgery and in 9.9% 3 months after surgery. One to two years after surgery, cognitive dysfunction was observed in 10.4% of patients compared with 10.6% in a control population of non-operated patients. We would suggest that in many cases, postoperative cognitive dysfunction may result from preoperative dementia unmasked by surgery.     

Postoperative psychosis after heart surgery.

One hundred heart surgery patients were followed throughout their postoperative periods to assess the incidence and etiology of postcardiotomy delirium. Factors evaluated were: age, sex, history of previous psychiatric illness, history of cerebrovascular disease, cardiac diagnosis and operation, time of anesthesia, time of bypass, time spent in the intensive-care unit, and amount of sleep during the postoperative period. Six patients developed delirium, five of whom had a lucid postoperative interval; four patients had perceptual disturbances only, without loss of contact with reality; three had neurological symptoms with mild confusion; 87 kept a clear mental state. The following factors tended to be related to the occurrence of delirium and perceptual disturbances: history of preoperative psychiatric illness, advanced age, severity of preoperative and postoperative illness, and time spent in the intensive-care unit. Sleep deprivation consistently preceded onset of these symptoms with one exception. Operative factors did not seem to be of major importance. While postoperative delirium probably has multidetermined causes, the author believes that sleep deprivation superimposed on the other contributory condition is a common precipitating factor. Suggestions about the prevention and treatment of delirium are made.     

老年患者口腔肿瘤皮瓣修复术后谵妄的相关危险因素分析

目的 通过回顾性分析,探讨老年患者口腔肿瘤皮瓣修复术后谵妄的相关危险因素.方法 通过检索电子病例系统,搜集2019年8月至2020年10月行口腔肿瘤皮瓣修复手术的老年患者360例,采集患者相关资料并评估术后谵妄的发生情况,排除未完成电话随访的病例后,最终有350例患者纳入本次研究,包括术后谵妄患者105例(D组),未发...     

Postoperative delirium and melatonin levels in elderly patients.

BACKGROUND: Melatonin, a hormone produced in the pineal gland, is involved in circadian rhythms and the sleep-wake cycle. Postoperative delirium is encountered frequently in elderly patients after major surgery; whether changes in the pattern of melatonin secretion are associated is unclear. METHODS: Plasma samples were obtained every 2 hours from 19 patients without delirium and 10 with delirium after major abdominal surgery. Postoperative delirium was determined using the Confusion Assessment Method in the Practice Guideline of the American Psychiatric Association. RESULTS: All patients without delirium showed nearly identical preoperative and postoperative melatonin secretion for 24 hours, although peak values were significantly lower in patients more than 80 years old (7.2 +/- 2.3 pg/mL) than in patients younger than 80 years (24.4 +/- 4.1 pg/mL, P = 0.022). Patients with delirium showed two different abnormal postoperative patterns: in 5 patients without complications, melatonin levels were lower than preoperative values (11.0 +/- 5.8 versus 6.5 +/- 4.2 pg/mL, P = 0.079); and in 5 patients with complications, melatonin levels were markedly increased (21.1 +/- 4.5 versus 58.8 +/- 12.4 pg/mL, P = 0.043). CONCLUSIONS: Abnormal melatonin secretion may be involved in postoperative sleep disturbances, which triggered delirium in elderly patients.     

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.     

睡眠质量对老年髋关节置换术后谵妄的影响

目的分析行髋关节置换术老年患者术前睡眠质量与术后谵妄之间联系。 方法回顾性收集在我院进行髋关节置换术的90例老年患者,男性46例、女性44例,年龄60~78岁,平均（72±5）岁。其治疗时间均在2018年1月至2019年1月之间,手术前采取匹兹堡睡眠质量指数量表对每位患者进行评估,依据患者睡眠情况将其分成睡眠正常组（n=43,睡眠指数<5分）,睡眠障碍组（n=47,睡眠指数≥5分）。每组均使用罗库溴铵、舒芬太尼以及丙泊酚诱导麻醉。分别记录每组麻醉时间、手术时间、观察时间以及手术后住院天数。比较手术后1~5 d内NRS得分、QoR-40得分以及术后谵妄出现次数。 结果90例患者均获得完整随访,随访率100.00%,随访时间6~18个月,平均（12.3±1.2）个月。睡眠障碍组在麻醉时间、手术时间、观察时间以及手术后住院天数方面均高于睡眠正常组（P<0.05）;睡眠障碍组手术后1~5 d NRS得分为（3.4±1.1）分、（3.2±1.0）分、（2.7±0.8）分、（2.1±0.6）分、（1.8±0.5）分,均高于睡眠正常组[（2.7±1.3）分、（2.5±1.0）分、（2.2±0.9）分、（1.8±0.7）分、（1.5±0.6）分,P<0.05];睡眠障碍组手术后1~5 d QoR-40得分为（146.1±6.2）分、（149.5±6.3）分、（154.2±6.7）分、（158.5±4.1）分、（162.1±5.2）分,均低于睡眠正常组[（149.2±5.1）分、（152.3±5.1）分、（158.3±5.5）分、（161.2±5.2）分、（165.6±4.1）分,P<0.05）];睡眠障碍组与睡眠正常组手术后1~5 d谵妄总出现率分别是34.04%（16/47）、13.95%（6/47）（P<0.05）。 结论手术前存在睡眠障碍会使患者术后谵妄出现几率上升,并且延长术后住院时间,不利于患者术后机体恢复,需对患者术前睡眠情况予以重视。     

经尿道前列腺电切术后谵妄诊治的临床分析

目的探讨经尿道前列腺电切术（TURP）后出现谵妄的相关因素，提高对该病的诊治水平。方法总结我院110例良性前列腺增生（BPH）患者行TURP术的临床资料，分析TURP术后发生谵妄的危险因素。年龄55-86岁，平均71．5岁，其中55-69岁57例，70岁以上53例。合并糖尿病者27例，高血压76例，冠心病29例，慢性支气管炎13例。所有患者无精神障碍和颅脑外伤病史。结果110例患者术后发生谵妄6例，表现为知觉障碍、语句不连贯、睡眠、清醒节律失调、定向失调和记忆力减退等。70岁以上的患者术后谵妄发生率明显增加，55-69岁及70岁以上患者谵妄发生率分别为1，7％和9．4％。结论高龄、疼痛和睡眠障碍是TURP术后发生谵妄的重要因素，术后良好的镇痛及充足的睡眠可有效预防术后谵妄的发生。     

Causes of postoperative delirium after abdominal surgery in elderly patients

BACKGROUND: There are many causes for postoperative delirium in elderly patients. Hypotension is considered as one of the causes. In our retrospective study, hypotension during operation was not taken care of strictly. Slight hypotension was observed every so often. We recognized that the drop of cerebral blood flow due to hypotension and duration of hypotension were risk factors of postoperative delirium. METHODS: We did a retrospective study, covering the period between April 1, 2005 and March 31, 2006, in 30 elderly patients for elective laparotomy. We compared postoperative delirium group (D group) with no delirium group (ND group). RESULTS: There were great differences in transfusion, fluid infusion, anesthesia time, operation time, blood loss, extreme hypotension and the duration of hypotension between the two groups. CONCLUSIONS: Our results indicate that permissive hypotension induced the drop of cerebral blood flow and it can be a risk factor of postoperative delirium in elderly patients. To prevent extreme hypotension, to decrease duration of hypotension, and to raise the blood pressure quickly are very important to decrease postoperative delirium in elderly patients.     

Postoperative delirium and health related quality of life after coronary artery bypass grafting

Objectives. We wanted to identify determinants for postoperative delirium and its influence on health related quality of life (HRQoL) during 36-month follow-up of coronary artery bypass (CABG) patients. Design. A total of 302 patients were retrospectively analyzed. HRQoL was assessed prospectively by the15D instrument. Delirium was diagnosed clinically. Results. The incidence of delirium was 6.0%. The cumulative survival (all-cause death) in 36 months was 96.1% in patients without delirium and 77.8% in patients with delirium. Age, cerebral disease, chronic heart failure, male gender, postoperative pneumonia and low output syndrome were predictors for delirium. Delirium patients needed more resources i.e. intensive care or total duration of hospitalization and experienced no positive change in HRQoL. Moreover patients with high preoperative 15D score tended to suffer fairly severe but reversible impairment during the first 6 months after the operation. Conclusions. Preoperatively older and sicker patients with complicated postoperative course are at higher risk of developing delirium after CABG. Preoperative status and operative complications together with delirium may exert negative influence on forthcoming HRQoL, which is seen especially in patients with a relatively high preoperative level of HRQoL.     

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。     

老年病人腹股沟疝修补术后并发症预防与治疗

老年腹股沟疝病人在成年病人中占比最高,减少其术后并发症发生具有重要意义。老年病人身体进入衰弱状态,生理储备能力下降,更易发生术后并发症,而且防治原则特殊。其中静脉血栓栓塞症致死风险最高,围手术期结合体格检查与实验室检查可精准预防;术后尿潴留最常见,应采取针对性防治措施;谵妄是老年病人独有的并发症,发病隐匿,须严密观察。在老年腹股沟疝病人的诊治过程中,外科医生须提高对这一特殊人群术后并发症的认识,做到术前准确评估、积极预防,术后随访观察、及时治疗。     

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.     

食管癌患者术前睡眠障碍与术后谵妄的相关性

目的探讨食管癌根治术患者术前睡眠障碍与术后谵妄(POD)的相关性,以及睡眠参数与POD的关系。方法选择2019年9—12月择期行食管癌根治术患者97例,男71例,女26例,年龄60～75岁,ASAⅠ或Ⅱ级。根据是否发生POD将患者分为两组:未发生POD组(nPOD组)和发生POD组(POD组)。采用双腔支气管插管全身麻醉,术中维持血流动力学平稳、采用小潮气量肺保护性通气策略,术后采用患者自控静脉镇痛(PCIA)。术前1 d采用匹兹堡睡眠质量指数(PSQI)量表评价睡眠质量,并记录入睡时间、觉醒次数、觉醒时间、睡眠时间等睡眠参数。术后1～7 d采用意识评估(CAM)量表进行认知功能评估。结果术后7 d内共有24例(25%)患者发生POD。与nPOD组比较,POD组术前合并睡眠障碍发生率明显升高,觉醒次数明显增多,觉醒时间明显延长,有效睡眠时间明显缩短,觉醒占总睡眠比例(WASO)明显升高(P0.05)。多因素Logistic回归分析结果显示,觉醒次数增加(OR=3.868,95%CI 1.645～9.006,P=0.002)和有效睡眠时间缩短(OR=3.802,95%CI 1.577～9.174,P=0.003)是POD的独立危险因素。结论术前合并睡眠障碍的食管癌根治术患者发生POD风险增加,睡眠中断以及有效睡眠时间缩短进一步增加POD发生风险。     

Melatonin for treatment and prevention of postoperative delirium.

Postoperative delirium is a common problem associated with increased morbidity and mortality, prolonged hospital stay, additional tests and consultations and therefore, increased cost (1,2). The reported incidence of delirium or confusion after surgery ranges from 8% to 78% (2,3-5), depending on methods and population studied. The elderly seem to be at significantly increased risk for this complication. Sleep-wake cycle disruption has been associated with delirium and behavioral changes (5) and sleep deprivation can even result in psychosis (6). Environmental changes (i.e., hospital stay), medications, and general anesthesia can affect the sleep-wake cycle (3,4). Plasma melatonin levels, which play an important role in the regulation of the sleep-wake cycle, are decreased after surgery (18) and in hospitalized patients (7,11). We report the successful use of melatonin in treating severe postoperative delirium unresponsive to antipsychotics or benzodiazepines in one patient. In another patient with a history of postoperative delirium, melatonin was used to prevent another episode of delirium after repeat lower extremity surgery. IMPLICATIONS: Postoperative delirium or confusion after surgery is a common problem associated with complications and death. Delirium has been linked to sleep-wake cycle disruption. Melatonin levels, which play an important role in regulating the sleep-wake cycle, are decreased after surgery. Two cases are presented where melatonin was used to treat and prevent postoperative delirium.     

Functional Outcome in Patients with Chronic Subdural Hematoma: Postoperative Delirium and Operative Procedure

Chronic subdural hematoma (CSDH) is a common neurosurgical condition and neurological condition improves after treatment in most patients. Recently more patients have poor prognosis because of aging of the population and presence of multiple comorbidities. The risk factors for poor prognosis, including postoperative delirium, were retrospectively evaluated to assess appropriate operative procedures. This study included 108 patients who underwent primary surgery from 2016 to 2017 at a single center. Operative procedures were drainage with or without irrigation. Functional outcome at discharge assessed the effect of various factors including postoperative delirium and operative procedure. Twenty-nine of 108 patients (27%) had worsened modified Rankin Scale (mRS) score at discharge, most with mobility disturbance or deteriorated cognitive function. Multivariate analysis found higher age (odds ratio [OR] = 5.13; 95% confidence interval [CI] = 1.0-1.14), poor pre-hospital mRS score (OR = 1.57; 95% CI = 1.0-2.46), and preoperative consciousness disturbance caused by CSDH (OR = 5.13; 95% CI = 1.27-20) were significant predictors of poor outcome. Operative procedure was not significantly related to functional outcome or recurrence, but irrigation was significantly related to postoperative delirium (OR = 4.83; 95% CI = 1.09-21.7). Patients with postoperative delirium were likely to require longer hospitalization stays (P = 0.028). Higher age, poor pre-hospital mRS, and preoperative consciousness disturbance caused by CSDH are the risk factors for poor recovery after CSDH. Irrigation is significantly likely to cause postoperative delirium and longer hospital stay.     

Prediction of postoperative delirium after abdominal surgery in the elderly

Purpose  Indications for the surgical treatment of elderly patients have been increasing. Postoperative central nervous system dysfunction, including delirium, is one of the most common complications in elderly surgical patients. The relationship between patient factors, including cerebral oxygen saturation, and the incidence of postoperative delirium was evaluated. Methods  Twenty American Society of Anesthesiologists (ASA) physical status I–II patients, older than 65 years, scheduled for elective abdominal surgery were enrolled in the study. The patients’ cognitive function was assessed, using the Hasegawa dementia score (HDS) and kana-hiroi test, on the day before surgery and then again 1 week after the surgery. Regional cerebral oxygen saturation () was continuously monitored during the surgery, using near-infrared spectroscopy (INVOS 3100). General anesthesia was induced with 3 mg·kg⁻¹ thiopental and 5% sevoflurane. After tracheal intubation, the sevoflurane concentration was adjusted to maintain the bispectral index (BIS) value between 45 and 60. Postoperative delirium was diagnosed if DSM IV criteria were present and the patient scored 12 or more points on the Delirium Rating Scale. Results  After surgery, 5 (25%) patients developed delirium. The age in the delirium (+) group (76 ± 4 years) was significantly higher than that in delirium (−) group (68 ± 3 years). Preoperative and postoperative HDS did not differ between the groups. The score on the preoperative kana-hiroi-test in the delirium (+) group (16 ± 5) was significantly lower than that in the delirium (−) group (32 ± 10). There were no significant differences between preoperative and postoperative kana-hiroi test scores in either group. Baseline in the delirium (+) group (60 ± 5%) was significantly lower than that in the delirium (−) group (66 ± 7%). However, there were no significant differences between the groups in the after the start of surgery. Conclusion  Patients’ age, low preoperative kana-hiroi test score, and low preoperative were important risk factors for postoperative delirium.