Postoperative delirium. Part 1: pathophysiology and risk factors

Delirium presents clinically with differing subtypes ranging from hyperactive to hypoactive. The clinical presentation is not clearly linked to specific pathophysiological mechanisms. Nevertheless, there seem to be different mechanisms that lead to delirium; for example the mechanisms leading to alcohol-withdrawal delirium are different from those responsible for postoperative delirium. In many forms of delirium, the brain's reaction to a peripheral inflammatory process is considered to be a pathophysiological key element and the aged brain seems to react more markedly to a peripheral inflammatory stimulus than a younger brain. The effects of inflammatory mediators on the brain include changes in neurotransmission and apoptosis. On a neurotransmitter level, impaired cholinergic transmission and disturbances of the intricate interactions between dopamine, serotonin and acetylcholine seem to play an important role in the development of delirium. The risk factors for delirium are categorised as predisposing or precipitating factors. In the presence of many predisposing factors, even trivial precipitating factors may trigger delirium, whereas in patients without or with only a few predisposing factors, a major precipitating insult is necessary to trigger delirium. Well documented predisposing factors are age, medical comorbidities, cognitive, functional, visual and hearing impairment and institutional residence. Important precipitating factors apart from surgery are admission to an ICU, anticholinergic drugs, alcohol or drug withdrawal, infections, iatrogenic complications, metabolic derangements and pain. Scores to predict the risk of delirium based on four or five risk factors have been validated in surgical patients.     

A randomised controlled trial of dexmedetomidine for delirium in adults undergoing heart valve surgery

Dexmedetomidine might reduce delirium after cardiac surgery. We allocated 326 participants to an infusion of dexmedetomidine at a rate of 0.6 μg kg⁻¹ for 10 min and then at 0.4 μg.kg⁻¹.h⁻¹ until the end of surgery; 326 control participants received comparable volumes of saline. We detected delirium in 98/652 (15%) participants during the first seven postoperative days: 47/326 after dexmedetomidine vs. 51/326 after placebo, p = 0.62, adjusted relative risk (95%CI) 0.86 (0.56–1.33), p = 0.51. Postoperative renal impairment (Kidney Disease Improving Global Outcomes stages 1, 2 and 3) was detected in 46, 9 and 2 participants after dexmedetomidine and 25, 7 and 4 control participants, p = 0.040. Intra-operative dexmedetomidine infusion did not reduce the incidence of delirium after cardiac valve surgery but might impair renal function.     

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。     

Delirium in the postoperative cardiac patient: a review

BACKGROUND AND AIM OF REVIEW: Cardiac surgery is increasingly common and relatively safe, but there are frequent reports of neuropsychiatric sequelae occurring in the postoperative period. One of the most common neuropsychiatric presentations of cardiac surgery is delirium, also called postcardiotomy delirium (PCD). Despite the vast numbers of cardiac surgeries performed today, there is a paucity of data on risk factors and management options of PCD available to the clinician. This review aims to summarize available information, increase clinicians' awareness of PCD and suggest effective management of this illness. METHODS: Our literature search was completed using the databases Medline and CINAHL; it was limited to human and English language studies from 1964 to the present. Search terms included "delirium," "agitation," "postoperative," "cardiac," "neuropsychiatric," "neuroleptics," "psychosis," "surgery," "treatment," "postcardiotomy," and "pharmacotherapy." RESULTS: Our review of the literature revealed several risk factors for PCD, as well as various options for its pharmacological management. CONCLUSIONS: A multifactorial model should be applied when considering risk stratification for and prevention of delirium postoperatively. Pharmacologically, conventional antipsychotic agents, such as haloperidol, have long been used to manage delirium. In light of haloperidol's side effects, particularly those applicable to the cardiac patient, further research is required into the role of second generation antipsychotics. These agents are common in clinical use, and may be the preferred medications.     

Effect of dexmedetomidine for prevention of acute kidney injury after cardiac surgery: an updated systematic review and meta-analysis

BackgroundAcute kidney injury (AKI) is a serious complication related to cardiac surgery. Several studies have been conducted to investigate the effect of dexmedetomidine administration on AKI prevention.ObjectiveTo assess if dexmedetomidine is associated with a protective effect of renal function after cardiac surgery. And the aim of conducting this meta-analysis is to summarize the literature and determine the clinical utility of dexmedetomidine administration in patients undergoing cardiac surgery.MethodsPubMed, Cochrane Library, and EMBASE databases were comprehensively searched for all randomized controlled trials (RCTs) published before 1 December, 2021 that investigated the effect of dexmedetomidine on AKI prevention.ResultsOur analysis included 16 studies involving 2148 patients. Compared with the control group, dexmedetomidine administration significantly reduced AKI incidence (OR, 0.47; 95% CI, 0.36–0.61; p <  0.00001; I² = 26%) and the length of stay in the intensive care unit (ICU) but did not alter mortality rate, length of stay in the hospital, and mechanical ventilation time. Furthermore, the incidence of delirium among patients treated with dexmedetomidine was significantly decreased.ConclusionDexmedetomidine administration has a positive effect on preventing AKI and postoperative delirium after cardiac surgery and significantly reduces the length of stay in the ICU.     

The effect of peri-operative dexmedetomidine on the incidence of postoperative delirium in cardiac and non-cardiac surgical patients: a randomised,double-blind placebo-controlled trial

Delirium occurs commonly following major non-cardiac and cardiac surgery and is associated with: postoperative mortality; postoperative neurocognitive dysfunction; increased length of hospital stay; and major postoperative complications and morbidity. The aim of this study was to investigate the effect of peri-operative administration of dexmedetomidine on the incidence of postoperative delirium in non-cardiac and cardiac surgical patients. In this randomised, double-blind placebo-controlled trial we included 63 patients aged ≥ 60 years undergoing major open abdominal surgery or coronary artery bypass graft surgery with cardiopulmonary bypass. The primary outcome was the incidence of postoperative delirium, as screened for with the Confusion Assessment Method. Delirium assessment was performed twice daily until postoperative day 5, at the time of discharge from hospital or until postoperative day 14. We found that dexmedetomidine was associated with a reduced incidence of postoperative delirium within the first 5 postoperative days, 43.8% vs. 17.9%, p = 0.038. Severity of delirium, screened with the Intensive Care Delirium Screening Checklist, was comparable in both groups, with a mean maximum score of 1.54 vs. 1.68, p = 0.767. No patients in the dexmedetomidine group died while five (15.6%) patients in the placebo group died, p = 0.029. For patients aged ≥ 60 years undergoing major cardiac or non-cardiac surgery, we conclude that the peri-operative administration of dexmedetomidine is associated with a lower incidence of postoperative delirium.     

Incidence and precipitating factors of delirium after coronary artery bypass grafting

Objective. To analyze large contemporary patient population, undergoing on-pump coronary artery bypass grafting at our institution, and identify the prevalence and precipitating factors of delirium development. Design. Baseline demographics, operative data and postoperative outcomes of 1367 consecutive patients were recorded prospectively and analysed using multivariate logistic regression analysis, to determine independent predictors of postoperative delirium development. Results. Delirium was detected in 42 (3.07%) patients. Eight factors: age more than 65 years, peripheral vascular disease, Euroscore≥5, preoperative IABP support, postoperative blood product usage and postoperative low cardiac output syndrome were independently predicting delirium development after coronary artery bypass procedures. Postoperative delirium was associated with significantly higher mortality rate (16.6% vs. 3.9%, p=0.013), prolonged mechanical ventilation time (9.2±3.1 vs. 5.05±7.6, p=0.04) and increased length of intensive care unit stay (6.8±4.9 vs. 2.0±2.7 days, p=0.001). Conclusions. Delirium is a dangerous complication, prolonging intensive care unit stay and postoperative mortality. Factors associated with delirium development are advanced age, peripheral vascular disease, diminished cardiac function and blood product usage.     

Psychotic symptoms in patients undergoing coronary artery bypass grafting and heart valve operation.

OBJECTIVE: Delirium on internal medicine and surgical wards of the general hospital is associated with several predisposing and precipitating factors as well as adverse outcomes. Whether psychosis, the symptom of delirium that may be recognized most promptly, is similarly associated with these factors and outcomes is largely unknown. METHODS: Eight thousand one hundred and thirty-nine consecutive patients undergoing coronary artery bypass grafting and/or heart valve operation were screened for preoperative predisposing factors and postoperative psychotic symptoms between January 1999 and July 2004. Data on per- and postoperative precipitating factors were collected in 4942 patients enrolled between January 2001 and July 2004. Data were examined using logistic regression to estimate odds ratios. RESULTS: The rate of severe psychotic symptoms was 2.1% (n=168). Higher age, renal failure, dyspnoea, heart failure, and left ventricle hypertrophy were independent preoperative predisposing factors. Peroperative hypothermia (<33 degrees C), hypoxemia, low hematocrit, renal failure, increased sodium, infection and stroke were independent precipitating factors. Psychotic symptoms were independently associated with a prolonged length of stay on the intensive care unit (odds ratio 7.8; 95% confidence interval 5.6-11), multi-organ failure or shock (3.2; 95% CI: 2.2-4.9), cardiopulmonary resuscitation (3.6; 95% CI: 2.1-6.2), and in-hospital death after surgery (2.1; 95% CI: 1.1-4.1). CONCLUSIONS: Psychotic symptoms are independently associated with several chronic and peroperative problems (including mild hypothermia during surgery), closely resembling those for delirium (with and without psychotic symptoms). Psychotic symptoms are also independently associated with adverse outcomes. Prompt diagnostic and therapeutic intervention aimed at the underlying problem may improve outcomes.     

A systematic review of the incidence of and risk factors for postoperative atrial fibrillation following general surgery

Atrial fibrillation is a common cardiac arrhythmia and can occur de novo following a surgical procedure. It is associated with increased inpatient and long‐term mortality. There is limited evidence concerning new‐onset atrial fibrillation following abdominal surgery. This study aimed to identify the prevalence of and risk factors for postoperative atrial fibrillation in the general surgical population. A systematic search of the Embase, MEDLINE and Cochrane (CENTRAL) databases was conducted. Studies were included in the review if they reported cases of new‐onset atrial fibrillation within 30 days of the index operation. Results were evaluated qualitatively due to substantial clinical heterogeneity. Incidence rates were pooled using a weighted random‐effects meta‐analysis model. A total of 835 records were initially identified, from which 32 full texts were retrieved. Following review, 13 studies were included that involved 52,959 patients, of whom 10.94% (95%CI 7.22–15.33) developed atrial fibrillation. Five studies of patients undergoing oesophagectomy (n = 376/1923) had a weighted average rate of 17.66% (95%CI 12.16–21.47), compared with 7.63% (95%CI 4.39–11.98) from eight studies of non‐oesophageal surgery (n = 2927/51,036). Identified risk factors included: increasing age; history of cardiac disease; postoperative complications, particularly, sepsis, pneumonia and pleural effusions. New‐onset postoperative atrial fibrillation is common, and is more frequent after surgery involving the thorax. Future work should focus on stratifying risk to allow targeted prophylaxis of atrial fibrillation and other peri‐operative complications.     

心脏手术后谵妄的危险因素分析及预测模型构建

目的 探讨心脏手术患者术后谵妄(POD)的危险因素,根据危险因素构建预测模型并评估其预测效能。
方法 本研究为回顾性病例-对照研究。收集2016年5月至2019年5月行心脏手术治疗的患者3 397例临床资料,提取性别、年龄、吸烟史、饮酒史、高血压病史、糖尿病史、高脂血症病史、脑血管疾病史、手术时间、心肺转流（CPB）时间、主动脉阻断时间、术中连续有创动脉血压值、术中出血量、术中麻醉药物使用情况、入ICU时Hb、白细胞计数、氧合指数（PaO2/FiO2）、血乳酸值、呼吸机使用时间、血管活性药物使用情况、术后左心室射血指数（LVEF）等临床指标,采用单因素分析评估上述指标与POD的相关性。采用逐步Logistic回归进行临床指标筛选并构建预测模型,绘制模型列线图,计算预测模型的受试者工作特征（ROC）曲线下面积（AUC）以及最佳阈值下的敏感性和特异性。
结果 有186例（5.48%）患者术后出现谵妄。与非谵妄患者比较,谵妄患者年龄、脑血管疾病和高血压病史比例、术中低血压比例、术中血压变异率、术中丙泊酚用量、术中出血量、术后乳酸值、术后白细胞显著增高的比例、术后左心室收缩功能不全（LVEF<50%）的比例以及术后应用肾上腺素和去甲肾上腺素比例明显增加（P<0.05）,手术时间和CPB时间、术中低血压时间以及术后机械通气时间明显延长（P<0.05）,术后氧合指数和Hb明显降低（P<0.05）。逐步Logistic回归分析显示,老年、脑血管疾病史、手术时间长、术中血压变异率大、术后Hb<100 g/L、机械通气时间延长以及左心室收缩功能不全、应用去甲肾上腺素是心脏手术后谵妄的独立危险因素。应用这些危险因素构建预测模型,AUC为0.932（95%CI 0.897～0.967）,敏感性78.2%,特异性93.5%。
结论 老年、脑血管疾病史、手术时间、术中血压变异率、术后Hb<100 g/L、机械通气时间延长以及左心室收缩功能不全、应用去甲肾上腺素是心脏手术后谵妄的独立危险因素,基于这些危险因素构建的模型可较好地预测心脏手术后谵妄的发生,为早期干预治疗提供参考。     

Dexmedetomidine for the prevention of delirium in adults admitted to the intensive care unit or post-operative care unit: A systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

Objectives

To assess any benefit or harm, we conducted a systematic review of randomised clinical trials (RCTs) allocating adults to dexmedetomidine versus placebo/no intervention for the prevention of delirium in intensive care or post-operative care units.

Data Sources

We searched Medline, Embase, CENTRAL and other databases. The last search was 9 April 2022.

Data Extraction

Literature screening, data extraction and risk of bias volume 2 assessments were performed independently and in duplicate. Primary outcomes were occurrences of serious adverse events (SAEs), delirium and all-cause mortality. We used meta-analysis, Trial Sequential Analysis, and GRADE (Grading Recommendations Assessment, Development and Evaluation).

Data Synthesis

Eighty-one RCTs (15,745 patients) provided data for our primary outcomes. Results from trials at low risk of bias showed that dexmedetomidine may reduce the occurrence of the most frequently reported SAEs (relative risk [RR] 0.69; 95% CI 0.43–1.09), cumulated SAEs (RR 0.70; 95% CI 0.52–0.95) and the occurrence of delirium (RR 0.62; 95% CI 0.43–0.89). The certainty of evidence was very low for delirium. Mortality was very low in trials at low risk of bias (0.4% in the dexmedetomidine groups and 1.0% in the control groups) and meta-analysis did not provide conclusive evidence that dexmedetomidine may result in lower or higher all-cause mortality (RR 0.47; 95% CI 0.18–1.21). There was a lack of information from trial results at low risk of bias for all primary outcomes.

Conclusions

Trial results at low risk of bias showed that dexmedetomidine might reduce occurrences of SAEs and delirium, while no conclusive evidence was found for effects on all-cause mortality. The certainty of evidence ranged from very low for occurrence of delirium to low for the remaining outcomes.     

Probable risk factors for postoperative delirium in patients undergoing spinal surgery

Postoperative delirium and its risk factors had been widely reported in several kinds of surgeries; however, there is only one known article relative to postoperative delirium in spinal surgery. We retrospectively examined the incidence of postoperative delirium and the probable risk factors in patients undergoing spinal surgery in our hospital, with the same aged non-delirium patients as controls, over a 6-month period. Studies about postoperative delirium were reviewed and referenced for variable factors collecting in our study. T tests, χ ² test and logistic regression analysis were performed to evaluate the various factors related to postoperative delirium. A total of 18 patients (3.3%), all of them were aged 54 years or older, had postoperative delirium after surgery. Patients without postoperative delirium aged 54 years or older served as the control group. The percentage of patients older than 65 years (P = 0.003), with comorbid diseases such as diabetes mellitus (P = 0.042) or central nervous system disorders (P = 0.013), with a surgical history (P = 0.028) in delirium group was larger than the control group. The absolute number of medications being taken before the operation in the delirium patients was also more than the control group (P = 0.000). The percentage of patients transfused with 800 mL or more blood was also larger (P = 0.024) in delirium group was larger than the control group. Logistic regression analysis showed that central nervous system disorder (OR 6.480), surgical history (OR 3.499), age older than 65 years (OR 3.390), diabetes mellitus (OR 2.981), transfused 800 mL or more blood (OR 2.537), and hemoglobin less than 100 g/L (OR 0.281) were significantly related to the occurrence postoperative delirium. Our findings suggest that postoperative delirium in spinal surgery can also occurred in younger patients and with an acceptable incidence in total. The risk for postoperative delirium is multifactorial. More prospective research is necessary in order to evaluate these and other risk factors in greater detail.     

Cerebrovascular autoregulation monitoring and patient‐centred outcomes after cardiac surgery: a systematic review

Background

Impaired cerebrovascular autoregulation (CVAR) is observed in up to 20% of cardiac surgical patients. This systematic review aims to evaluate the association between impaired CVAR, measured by current monitoring techniques, and patient‐centred outcomes in adults following cardiac surgery.

Methods

MEDLINE, EMBASE, PubMed, MEDLINE In‐Process and Cochrane Library were systematically searched through 8 December 2017. Studies were included if they assessed associations between CVAR and patient‐centred outcomes in the adult cardiac surgical population. The primary outcome of this systematic review was mortality. Secondary outcomes were stroke, delirium and acute kidney injury. Risk of bias was systematically assessed, and the GRADE methodology was used to evaluate the quality of evidence across outcomes.

Results

Eleven observational studies and no randomised controlled trials met the inclusion criteria. Due to methodological heterogeneity, meta‐analysis was not possible. There was a high risk of bias within individual studies and low quality of evidence across outcomes. Of the included studies, one assessed mortality, five assessed stroke, four assessed delirium, and three assessed acute kidney injury. No reliable conclusions can be drawn from the one study assessing mortality. Interpretation of studies investigating CVAR and stroke, delirium and acute kidney injury was complicated by the lack of standardisation of monitoring techniques as well as varying definitions of impaired CVAR.

Conclusions

There is a paucity of high quality evidence for CVAR monitoring and its associations with outcome measures in post‐cardiac surgical patients, highlighting the need for future studies.

     

Association between perioperative hypotension and postoperative delirium and atrial fibrillation after cardiac surgery: A post-hoc analysis of the DECADE trial

Study objectiveTo test the hypotheses that in adults having cardiac surgery with cardio-pulmonary bypass, perioperative hypotension increases the risk of delirium and atrial fibrillation during the initial five postoperative days.DesignSub-analysis of the DECADE multi-center randomized trial.SettingPatients who had cardiac surgery with cardiopulmonary bypass at the Cleveland Clinic.InterventionsIn the underlying trial, patients were randomly assigned 1:1 to dexmedetomidine or normal saline placebo.MeasurementsIntraoperative mean arterial pressures were recorded at 1-min intervals from arterial catheters or at 1–5-min intervals oscillometrically. Postoperative blood pressures were recorded every half-hour or more often. The co-primary outcomes were atrial fibrillation and delirium occurring between intensive care unit admission and the earlier of postoperative day 5 or hospital discharge. Delirium was assessed twice daily during the initial 5 postoperative days while patients remained hospitalized with the Confusion Assessment Method for the intensive care unit. Assessments were made by trained research fellows who were blinded to the dexmedetomidine administration.Main resultsThere was no significant association between intraoperative hypotension and delirium, with an adjusted odds ratio of 0.94 (95% CI: 0.81, 1.09; P = 0.419) for a doubling in AUC of mean arterial pressure (MAP) <60 mmHg. An increase in intraoperative AUC of MAP <60 mmHg was not significantly associated with the odds of atrial fibrillation (adjusted odds ratio = 0.99; 95% CI: 0.87, 1.11; P = 0.819). Postoperative MAP <70 mmHg per hour 1.14 (97.5% CI: 1.04,1.26; P = 0.002) and MAP <80 mmHg per hour 1.05 (97.5%: 1.01, 1.10; P = 0.010) were significantly associated with atrial fibrillation.ConclusionsIn patients having cardiac surgery with cardio-pulmonary bypass, neither intraoperative nor postoperative hypotension were associated with delirium. Postoperative hypotension was associated with atrial fibrillation, although intraoperative hypotension was not.     

Contribution of sedative-hypnotic agents to delirium via modulation of the sleep pathway

Purpose

To review the mechanisms of sedative-hypnotic action with respect to the risk of delirium imparted by drugs that act on γ-amino-butyric-acid type A receptors or α₂ adrenoceptors.

Source

MEDLINE was searched for relevant articles.

Principal findings

Development of the acute confusional state of delirium is associated with longer intensive care unit (ICU) and hospital lengths of stay, significantly higher risk of functional decline, and increased mortality. Disruption of sleep is a modifiable risk factor that may contribute to delirium and cognitive dysfunction in ICU patients. Among the functions of sleep are repair of defective processes and restoration of the brain to a state in which it is ready to acquire new knowledge. It is logical that disruption of these processes may produce acute confusion. Delirium develops through a complex interaction between the patient’s baseline vulnerability (patient’s predisposing risk factors before hospitalization) and precipitating factors or insults (modifiable events that occur during hospitalization). The latter factors include both sleep disruption and sedation. We present a hypothesis that these two factors are causally linked through effects on memory. Our hypothesis explains why patients randomized to receive an α₂ adrenoceptor agonist are less likely to develop delirium (and the attendant cognitive dysfunction) than those randomized to receive benzodiazepines.

Conclusion

Herein we present our hypothesis that alternate mechanisms of hypnotic action may differentiate the deleriogenic properties of the two classes of sedatives. Future studies should focus on whether a causal relationship can be established between sedative administration, sleep disruption, and delirium.     

Pathogenesis of and management strategies for postoperative delirium after hip fracture: a review

BACKGROUND: Postoperative delirium is a frequent and serious complication in elderly patients following operation for hip fracture, leading to an increased risk of complications. The pathophysiological mechanisms are unresolved, but probably multifactorial. The purpose of this review is to summarize current knowledge about the pathogenesis of postoperative delirium with a view to finding strategies for prevention and management. METHOD: We conducted an Internet search through the Medline database (1966-March 2003) and supplemented it with a manual search. We included 12 studies which specifically discussed pathogenic factors or interventions against postoperative delirium following operation for hip fracture. RESULTS: 1,823 patients were included with an average incidence of delirium of 35%. We concentrated on pre-, intra-, and postoperative risk factors. Only advanced age and dementia met our fixed criterion of "strong evidence" for a significant association. Hence, from the studies that we reviewed we were unable to find intraoperative or postoperative factors with "strong evidence" for a significant association with delirium. INTERPRETATION: Postoperative delirium is a serious complication. The pathophysiology leading to delirium after hip fracture surgery still remains to be clarified and no single drug or surgical regimen has proven to be preventive. This calls for more detailed investigations of the differential role of different pathogenic mechanisms, as well as an aggressive multimodal approach to enhance recovery and reduce morbidity, as has proven to be successful in a variety of elective surgical procedures. Such multimodal interventional studies represent a major task for orthopedic departments in collaboration with anesthesiologists, geriatricians, physiotherapists and nursing staff.     

Perioperative use of alpha2-adrenoceptor agonists and the cardiac patient

The centrally acting alpha2-adrenoceptor agonists clonidine and dexmedetomidine have been used with success to provide haemodynamic stability for patients undergoing surgery. Particularly in the case of patients with overt or underlying cardiac disease the actions of alpha2-adrenoceptor agonists, which include maintenance of stable systemic blood pressure and low heart rate and a reduction in overall oxygen consumption, can be expected to reduce the risk of procedure-related cardiac events. This expectation has been corroborated in clinical trials with clonidine, dexmedetomidine and mivazerol and meta-analyses; additional large controlled trials would be instructive in establishing a robust estimate of the scale of the benefit. In addition, alpha2-adrenoceptor agonists used as premedication have been shown to substantially reduce anaesthetic requirements among surgical patients, and the use of these agents has been associated with a reduced risk of postoperative delirium, which may be expected to improve considerably the postoperative course for at-risk patients. Dexmedetomidine is the only alpha2-adrenoceptor agonist currently approved for use in the intensive care unit. A distinctive feature of dexmedetomidine in that setting is that in addition to haemodynamic stability it confers a distinctive and advantageous quality of sedation: patients are tranquil but responsive to requests from attending staff. This review examines the pharmacological principles underlying the use of alpha2-adrenoceptor agonists as adjuncts to surgery and clinical experience in that indication.     

Incidence of preoperative instrumental activities of daily living (IADL) dependence and adverse outcomes in older surgical patients: A systematic review and meta-analysis

Study objectiveInstrumental activities of daily living (IADLs) are essential to patient function and quality of life after surgery. In older surgical patients, the incidence of preoperative IADL dependence has not been well characterized in the literature. This systematic review and meta-analysis aimed to determine the pooled incidence of preoperative IADL dependence and the associated adverse outcomes in the older surgical population.DesignSystematic review and meta-analysis.SettingMEDLINE, MEDLINE Epub Ahead of Print and In-Process, In-Data-Review & Other Non-Indexed Citations, Embase/Embase Classic, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews, ClinicalTrials.Gov, the WHO ICTRP (International Clinical Trials Registry Platform) were searched for relevant articles from 1969 to April 2022.PatientsPatients aged ≥60 years old undergoing surgery with preoperative IADL assessed by the Lawton IADL Scale.InterventionsPreoperative assessment.MeasurementThe primary outcome was the pooled incidence of preoperative IADL dependency. Additional outcomes included post-operative mortality, postoperative delirium [POD], functional status improvement, and discharge disposition.Main resultsTwenty-one studies (n = 5690) were included. In non-cardiac surgeries, the pooled incidence of preoperative IADL dependence was 37% (95% CI: 26.0%, 48.0%) among 2909 patients. Within cardiac surgeries, the pooled incidence of preoperative IADL dependence was 53% (95% CI: 24.0%, 82.0%) among 1074 patients. Preoperative IADL dependence was associated with an increased risk of postoperative delirium than those without IADL dependence (44.9% vs 24.4, OR 2.26; 95% CI: 1.42, 3.59; I²: 0%; P = 0.0005).ConclusionsThere is a high incidence of IADL dependence in older surgical patients undergoing non-cardiac and cardiac surgery. Preoperative IADL dependence was associated with a two-fold risk of postoperative delirium. Further work is needed to determine the feasibility of using the IADL scale preoperatively as a predictive tool for postoperative adverse outcomes.     

Incidence of postoperative delirium is high even in a population without known risk factors

Purpose

Postoperative delirium is a recognized complication in populations at risk. The aim of this study is to assess the prevalence of early postoperative delirium in a population without known risk factors admitted to the ICU for postoperative monitoring after elective major surgery. The secondary outcome investigated is to identify eventual independent risk factors among demographic data and anesthetic drugs used.

Methods

An observational, prospective study was conducted on a consecutive cohort of patients admitted to our ICU within and for at least 24 h after major surgical procedures. Exclusion criteria were any preexisting predisposing factor for delirium or other potentially confounding neurological dysfunctions. Patients were assessed daily using the confusion assessment method for the ICU scale for 3 days after the surgical procedure. Early postoperative delirium incidence risk factors were then assessed through three different multiple regression models.

Results

According to the confusion assessment method for the ICU scale, 28 % of patients were diagnosed with early postoperative delirium. The use of thiopentone was significantly associated with an eight-fold-higher risk for delirium compared to propofol (57.1 % vs. 7.1 %, RR = 8.0, χ ² = 4.256; df = 1; 0.05 < p < 0.02).

Conclusion

In this study early postoperative delirium was found to be a very common complication after major surgery, even in a population without known risk factors. Thiopentone was independently associated with an increase in its relative risk.     

Treatment of Delirium Following Cardiac Surgery

Abstract Postoperative delirium is a common medical complication following cardiac surgery. This paper will outline the treatment options for delirium with a focus on prophylactic use of risperidone before cardiac surgery. (J Card Surg 2012;27:589‐593)