心肺转流心脏手术术后谵妄的预防

术后谵妄是手术后常见的神经系统并发症,表现为急性发作的注意力不集中、思维混乱和意识水平的改变等。心肺转流心脏手术患者的术后谵妄发生率明显高于其他类型手术,严重影响患者术后恢复和生存质量。尽管不能完全避免术后谵妄的发生,但有效的预防措施可以明显降低心肺转流心脏手术患者术后谵妄的发生率。本文章回顾近年来国内外术后谵妄的相关研究,简要总结术后谵妄的发生机制,以时间轴为导向,分别以术前、术中、术后三个时段展开,从药物和非药物两方面对心肺转流心脏手术术后谵妄的预防策略进行综述,为临床上更好地预防术后谵妄的发生提供参考。     

Efficacy of risperidone for prevention of postoperative delirium in cardiac surgery

This randomised, double-blinded, placebo-controlled study was primarily aimed to evaluate the potential of risperidone to prevent postoperative delirium following cardiac surgery with cardiopulmonary bypass and the secondary objective was to explore clinical factors associated with postoperative delirium. One-hundred-and-twenty-six adult patients undergoing elective cardiac surgery with cardiopulmonary bypass were randomly assigned to receive either 1 mg of risperidone or placebo sublingually when they regained consciousness. Delirium and other outcomes were assessed. The confusion assessment method for intensive care unit was used to assess postoperative delirium. The incidence of postoperative delirium in the risperidone group was lower than the placebo group (11.1% vs. 31.7% respectively, P=0.009, relative risk = 0.35, 95% confidence interval [CI] = 0.16-0.77). Other postoperative outcomes were not statistically different between the groups. In exploring the factors associated with delirium, univariate analysis showed many factors were associated with postoperative delirium. However multiple logistic regression analysis showed a lapse of 70 minutes from the time of opening eyes to following commands and postoperative respiratory failure were independent risk factors (P=0.003, odds ratio [OR] = 4.57, 95% CI = 1.66-12.59 and P=0.038, OR = 13.78, 95% CI = 1.15-165.18 respectively). A single dose of risperidone administered soon after cardiac surgery with cardiopulmonary bypass reduces the incidence of postoperative delirium. Multiple factors tended to be associated with postoperative delirium, but only the time from opening eyes to following commands and postoperative respiratory failure were independent risk factors in this study.     

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy

BACKGROUND: Despite refinements in perioperative patient management postoperative renal failure requiring hemofiltration or dialysis is still a common complication after coronary artery bypass grafting associated with impaired patient outcome. METHODS: Prospective data on 9,631 patients receiving myocardial revascularization with (coronary artery bypass grafting [n = 8,870]) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting [n = 761]) between April 1996 and August 2001 were evaluated by univariate and multivariate logistic regression analysis. RESULTS: Overall prevalence of postoperative continuous renal replacement therapy was 4.1% (coronary artery bypass grafting, 4.3%; off-pump coronary artery bypass grafting, 1.8%; p = 0.001). Thirty of 40 selected preoperative and intraoperative patient and treatment related variables had a high association with the requirement for postoperative renal replacement therapy; fifteen of these variables were independent predictors in the whole study population. Off-pump coronary artery bypass surgery was identified as having a significantly lower predictive value for postoperative continuous renal placement therapy. In the subgroup of patients undergoing off-pump coronary artery bypass grafting surgery, a second multivariate logistic regression model revealed preoperative cardiogenic shock, urgent operation, intraoperative low cardiac output, and high transfusion requirement as independent predictors for postoperative renal replacement therapy. CONCLUSIONS: Patients with preoperative nondialysis dependent renal insufficiency are at a high risk for further decline in renal function requiring postoperative continuous renal replacement therapy. Off-pump coronary artery bypass surgery is associated with a lower prevalence of postoperative renal replacement therapy after coronary artery bypass grafting.     

Stroke after cardiac surgery: a risk factor analysis of 16,184 consecutive adult patients

BACKGROUND: Stroke remains a devastating complication after cardiac surgical procedures despite advances in perioperative monitoring and management. The purpose of this study was to determine the predictors of stroke in a large, contemporary cardiac surgery population. METHODS: Prospective data on 16,184 consecutive patients undergoing cardiac surgery (coronary artery bypass grafting [CABG], n = 8,917; beating heart CABG, n = 1,842; aortic valve surgery, n = 1,830; mitral valve surgery, n = 708; double or triple valve surgery, n = 381; CABG and valve surgery, n = 2,506) between April 1996 and August 2001 were subjected to univariate and multivariate analysis. Stroke was defined as any new permanent (manifest stroke) or temporary neurologic deficit or deterioration (transient ischemic attack or prolonged reversible ischemic neurologic deficit) and was confirmed by computed tomography or magnetic resonance imaging whenever possible. RESULTS: Overall incidence of stroke was 4.6% and varied between surgical procedures (CABG 3.8%; beating-heart CABG 1.9%; aortic valve surgery 4.8%; mitral valve surgery 8.8%; double or triple valve surgery 9.7%; CABG and valve surgery 7.4%). Of 63 patient-specific and treatment variables, 54 were found to have a significant univariate association with postoperative stroke. Multivariable analysis revealed 10 variables that were independent predictors of stroke: history of cerebrovascular disease, peripheral vascular disease, diabetes, hypertension, previous cardiac surgery, preoperative infection, urgent operation, CPB time more than 2 hours, need for intraoperative hemofiltration, and high transfusion requirement. Beating heart CABG was associated with a lower incidence of stroke in this multivariable analysis. CONCLUSIONS: Identification of predictors for stroke is important for understanding the pathogenesis of this devastating complication as well as for developing preventative strategies. Although retrospective analyses can be subject to selection bias we believe beating heart CABG is associated with a lower incidence of stroke and may therefore improve patient outcomes.     

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.     

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.     

Atrial fibrillation after coronary artery bypass grafting without cardiopulmonary bypass.

OBJECTIVE: Atrial fibrillation is the most common complication after heart surgery. It rarely has a fatal outcome but causes patient instability, prolongs hospital stay, or even is the reason for perioperative infarction. Although conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass has excellent short-term and long-term results, the number of coronary operations on a beating heart without cardiopulmonary bypass is still growing. To reduce surgical trauma, off-pump coronary artery bypass grafting via sternotomy (OPCABG) or minimally invasive direct vision coronary artery bypass grafting (MIDCABG) via small thoracotomy are performed. The aim of this study was to estimate the frequency of atrial fibrillation in patients after myocardial revascularization without cardiopulmonary bypass. METHODS: A retrospective analysis of 48 patients undergoing myocardial revascularization without cardiopulmonary bypass was performed. Twenty-four patients underwent OPCABG and 24 were operated using the MIDCABG technique. The incidence of cardiac arrhythmias was analyzed since operation to the fourth postoperative day. Each patient had continuous ECG monitoring with option of arrhythmia analysis during ICU stay. After discharge from ICU 24-h ECG monitor studies were carried out. Surface 12-lead ECG was accomplished once a day, and additionally each time symptoms of cardiac arrhythmia occurred. Risk factors of atrial fibrillation were estimated. RESULTS: Atrial fibrillation occurred in 25% of patients after MIDCABG, in 29% after OPCABG, and in 18% after CABG with cardiopulmonary bypass. This difference has no statistical significance. Risk factors and incidence of postoperative complications were comparable in all groups. CONCLUSIONS: Atrial fibrillation is a common complication after procedures of myocardial revascularization, performed with or without cardiopulmonary bypass. The occurrence is not dependent on the type of operation.     

Cerebral oximetry and postoperative delirium after cardiac surgery: a randomised,controlled trial

Postoperative delirium is associated with increased morbidity and mortality. We hypothesised that restoration of regional cerebral oxygen desaturation would reduce the incidence of postoperative delirium in elderly patients after cardiac surgery. After institutional ethics review board approval and informed consent, a double‐blinded, prospective, randomised, controlled trial was conducted in patients ≥ 60 years of age undergoing cardiac surgery with cardiopulmonary bypass. In the intervention group, an algorithm was commenced if regional cerebral oxygen saturation decreased below 75% of baseline value for 1 min or longer. In the control group, the cerebral oximetry monitor screen was electronically blinded. Assessment of delirium was performed with confusion assessment method for intensive care unit or confusion assessment method after discharge from intensive care unit at 12‐h intervals for seven postoperative days. Postoperative delirium was present in 30 out of 123 (24.4%) and 31 out of 126 (24.6%) patients in the intervention and control groups, respectively, odds ratio 0.98 (95%CI 0.55–1.76), p = 0.97. Postoperative delirium was present in 20 (71%) out of 28 and in 41 (18%) out of 221 patients with baseline regional cerebral oxygen saturation ≤ 50, or > 50%, respectively, p = 0.0001. Higher baseline regional cerebral oxygen saturation and body mass index were protective against postoperative delirium. Restoration of regional cerebral oxygen desaturation did not result in lower postoperative delirium after cardiac surgery. Pre‐operative regional cerebral oxygen saturation ≤ 50% was associated with increased postoperative delirium rates in elderly patients following cardiac surgery.     

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。     

Neuropsychologic impairment after coronary bypass surgery: effect of gaseous microemboli during perfusionist interventions

OBJECTIVE: Neuropsychologic impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass are the principal cause of cognitive deficits after coronary bypass grafting. We have previously demonstrated that the majority of cerebral emboli occur during perfusionist interventions (ie, during the injection of air into the venous side of the cardiopulmonary bypass circuit). The purpose of this study was to determine whether an increase in perfusionist interventions is associated with an increased risk of postoperative cognitive impairment. METHODS: Patients undergoing elective coronary artery bypass grafting (n = 83) underwent a battery of neuropsychologic tests preoperatively and 3 months postoperatively. Patients were divided into 2 groups according to the median value of perfusionist interventions during cardiopulmonary bypass. Group 1 patients (n = 42) had fewer than 10 perfusionist interventions, and group 2 patients (n = 41) had 10 or more interventions. RESULTS: The 2 groups of patients were similar for all preoperative, intraoperative, and postoperative variables, with the exception of longer cardiopulmonary bypass times in group 2 patients (P <.001). Group 2 patients had lower mean scores on 9 of 10 neuropsychologic tests, with 3 (Rey Auditory Verbal Learning, Digit Span, and Visual Span) being statistically significant. Group 2 patients had worse cognitive test scores, even when controlling for increased bypass times. Group 2 patients had a nonsignificant trend toward an increased prevalence of neuropsychologic impairment 3 months postoperatively. CONCLUSIONS: Introduction of air into the cardiopulmonary bypass circuit by perfusionists, resulting in cerebral microembolization, may contribute to postoperative cognitive impairment.     

Renal dysfunction after cardiac surgery with normothermic cardiopulmonary bypass: incidence,risk factors,and effect on clinical outcome

Renal dysfunction is a frequent and severe complication after conventional hypothermic cardiac surgery. Little is known about this complication when cardiopulmonary bypass (CPB) is performed under normothermic conditions (e.g., more than 36 degrees C). Thus, we prospectively studied 649 consecutive patients undergoing coronary artery bypass surgery or valve surgery with normothermic CPB. The association between renal dysfunction (defined as a > or =30% preoperative-to-maximum postoperative increase in serum creatinine level) and perioperative variables was studied by univariate and multivariate analysis. Renal dysfunction occurred in 17% of the patients. Twenty-one (3.2%) patients required dialysis. Independent preoperative predictors of this complication were: advanced age, ASA class >3, active infective endocarditis, radiocontrast agent administration <48 h before surgery, and combined surgery. When all the variables were entered, active infective endocarditis, radiocontrast agent administration, postoperative low cardiac output, and postoperative bleeding were independently associated with renal dysfunction. The in-hospital mortality rate was 27.5% when this complication occurred (versus 1.6%; P < 0.0001). Furthermore, postoperative renal dysfunction was independently associated with in-hospital mortality (odds ratio, 4.1 [95% confidence interval, 1.3-12.8]). We conclude that advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration, as well as postoperative hemodynamic dysfunction, are more consistently predictive of postoperative renal dysfunction than CPB factors. IMPLICATIONS: We found that postoperative renal dysfunction was a frequent and severe complication after normothermic cardiac surgery, independently associated with poor outcome. Independent predictors of this complication were advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration (the only preoperative modifiable factor), as well as postoperative hemodynamic dysfunction.     

Predictive value of S-100beta and neuron-specific enolase serum levels for adverse neurologic outcome after cardiac surgery

OBJECTIVES: The aim of this study was to evaluate the time course of S-100beta and neuron-specific enolase serum levels after cardiac surgery and their clinical relevance in predicting postoperative adverse neurologic outcomes; the 2 proteins are only released in peripheral blood in association with nervous system lesions. METHODS: We neurologically assessed 190 consecutive patients undergoing elective cardiac operations for coronary artery bypass (n = 147), valve replacement (n = 29), or both (n = 14), before as well as after the operation. Postoperative outcome was classified as type I (uncomplicated), type II (confusion, agitation, disorientation, or epileptic seizures), or type III (stroke, stupor, or coma). Levels of S-100beta and neuron-specific enolase were evaluated in venous blood samples drawn preoperatively and then daily in the first 5 postoperative days. RESULTS: Levels of S-100beta and neuron-specific enolase differed significantly among the 3 groups (type III > type II > type I) throughout the postoperative period and had a diagnostic specificity and specificity of 89% and 79%, respectively, in identifying patients with type III outcome. S-100beta (but not neuron-specific enolase) levels were identified as significant independent predictors for type II and III outcomes (odds ratio 16.2, P <.0004). The same was true for duration of cardiopulmonary bypass (odds ratio 1.02, P <.006). CONCLUSIONS: Serum levels of S-100beta are reliable markers for adverse neurologic outcomes after cardiac surgery.     

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.     

冠状动脉旁路移植术后患者谵妄独立预测因子的现况分析

目的找出能引起谵妄的独立危险因素,为建立一套适合我国国情的冠状动脉旁路移植术后患者谵妄风险预测模型提供依据。方法通过文献检索,收集现有的冠状动脉旁路移植术后谵妄风险预测模型中纳入的独立预测因子并进行分析。结果收集18个模型,共44个独立预测因子。年龄、简易精神状态评分是引起冠状动脉旁路移植术后谵妄发生的前2位独立预测因子,分别累计出现6次和4次。第3位的独立预测因子有6个,分别为血浆皮质醇浓度、手术时间、欧洲心血管手术危险因素评分、房颤、体外循环时间、糖尿病,分别累计出现3次。结论围术期冠状动脉旁路移植术谵妄预测因子众多,谵妄的临床表现复杂,如何在现有众多预测因子中筛查出特异性强、敏感度高的独立预测因子,是建立冠状动脉旁路移植术后谵妄风险预测理想模型的关键。     

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.     

Report of a substudy on warm versus cold cardiopulmonary bypass: changes in creatinine clearance.

BACKGROUND: Renal dysfunction remains a major complication of cardiac operations. There is concern regarding the possibility of increased renal injury during warm cardiopulmonary bypass (CPB). Therefore, we tested the hypothesis that warm CPB is associated with a greater reduction in creatinine clearance after cardiac surgery than hypothermic CPB. METHODS: We randomly assigned 300 patients who had elective coronary artery bypass grafting to warm (35.5 to 36.5 degrees C) or cold (28 degrees C to 30 degrees C) CPB. Preoperative and peak postoperative serum creatinine values were recorded. Creatinine clearance was estimated using the Cockroft Gault equation. Univariate and multivariable analyses were performed to test the association of CPB temperature and perioperative change in creatinine clearance. RESULTS: Demographic variables were similar between groups. Multivariable analysis did not confirm an association between temperature and change in creatinine clearance (p = 0.87). CONCLUSIONS: We did not confirm an association between warm CPB and increased renal dysfunction after cardiac operations compared with hypothermic CPB.     

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.     

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.     

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.     

Adult respiratory distress syndrome after cardiac surgery

Adult respiratory distress syndrome, characterized by high permeability pulmonary oedema caused by endothelial cell damage, resulting in refractory hypoxemia, has a very high mortality. Cardiopulmonary bypass is said to be responsible for the development of adult respiratory distress syndrome after cardiac surgery. The present study was performed in order to identify predicting and aetiological factors of adult respiratory distress syndrome and multiple organ failure after cardiac surgery. Between January 1984 and December 1993, 3848 patients underwent cardiac surgery with cardiopulmonary bypass in the authors' institution, and were analysed in a retrospective manner. The operations performed were 3444 coronary artery bypass grafts (CABG), 267 valve and 137 combined (CABG + valve) procedures. The incidence of adult respiratory distress syndrome was 1.0% (38 of 3848) with an overall mortality rate of 68.4% (26 patients); 24 of these died from multiple organ failure. Multivariate regression analysis identified hypertension, current smoking, emergency surgery, preoperative New York Heart Association (NYHA) class 3 and 4, low postoperative cardiac output and left ventricular ejection fraction < 40% as significant, independent predictors for adult respiratory distress syndrome. Combined cardiac surgery and diffuse coronary disease were also significant predictors; cardiopulmonary bypass time was not. Thirty-six of the 38 patients that later developed adult respiratory distress syndrome had low postoperative cardiac output, 12 requiring intra-aortic balloon pump support. The remaining two had severe hypotension caused by postoperative bleeding. Twenty-six adult respiratory distress syndrome patients (68%) had confirmed gastrointestinal complications (e.g. intestinal ischaemia). Adult repiratory distress syndrome is a rare complication after cardiac surgery but is associated with a very high mortality. Preoperative predictors were identified. Cardiopulmonary bypass alone was not found to be an important factor. Postoperative low cardiac output leading to splanchnic hypoperfusion may be the most important single factor in developing adult respiratory distress syndrome after cardiac surgery.