A prospective cohort study evaluating associations among delirium, postoperative cognitive dysfunction, and apolipoprotein E genotype following open aortic repair

Background

Patients undergoing major vascular surgery are at high risk of postoperative delirium and postoperative cognitive dysfunction (POCD). Apolipoprotein E (APOE) is involved in central acetylcholine synthesis, and patients bearing the ε4 genotype (APOE-ε4) are at increased risk of both vascular dementia and peripheral vascular disease. The purpose of this study was to evaluate the associations among delirium, POCD, and APOE-ε4 in patients undergoing open aortic repair.

Methods

Following Research Ethics Board approval and written informed consent, we recruited a cohort of patients ≥ 60 yr of age undergoing open aortic repair. Apolipoprotein E genotyping and a battery of nine neuropsychometric (NP) tests were performed prior to surgery. Delirium was assessed on postoperative days two, four, and discharge using the Confusion Assessment Method. Neuropsychometric testing was repeated at discharge and again three months following surgery. A group of non-surgical patients was used to adjust NP scores using reliable change index methodology. Logistic regression was used to evaluate independent predictors of both delirium and POCD.

Results

Eighty-eight patients underwent surgery, 78 completed NP testing on discharge, and sixty-nine completed NP testing at three months. Delirium was noted in 36% of patients after surgery, while POCD was noted in 62% at discharge and 6% at three months. Delirium predicted POCD at discharge (odds ratio 2.86; 95% confidence intervals 0.99 to 8.27) but not at three months. Apolipoprotein E-ε4 genotype was not associated with either delirium or POCD following adjustment for covariates.

Conclusion

Both delirium and POCD are common following open aortic repair; however, the APOE genotype did not predict either condition. This trial has been registered with ClinicalTrials.gov (NCT00911677).     

A Comparison of Three Scores to Screen for Delirium on the Surgical Ward

Background

Postoperative delirium is associated with adverse outcome. The aim of this study was to find a valid and easy-to-use tool to screen for postoperative delirium on the surgical ward.

Methods

Data were collected from 88 patients who underwent elective surgery. Delirium screening was performed daily until the sixth postoperative day using the Confusion Assessment Method (CAM), the Nursing Delirium Screening Scale (Nu-DESC), and the Delirium Detection Score (DDS), and the DSM-IV criteria as the gold standard.

Results

Seventeen of 88 patients (19%) developed delirium on at least one of the postoperative days according to the gold standard. The DDS scored positive for 40 (45%) patients, the CAM for 15 (17%), and the Nu-DESC for 28 (32%) patients. Sensitivity and specificity were 0.71 and 0.87 for the DDS, 0.75 and 1.00 for the CAM, and 0.98 and 0.92 for the Nu-DESC. The interrater reliability was 0.83 for the Nu-DESC, 0.77 for the DDS, and 1.00 for the CAM.

Conclusions

All scores showed high specificity but differed in their sensitivity. The Nu-DESC proved to be the most sensitive test for screening for a postoperative delirium on the surgical ward followed by the CAM and DDS when compared to the gold standard.     

Intraoperative ketamine administration to prevent delirium or postoperative cognitive dysfunction: A systematic review and meta‐analysis

Background

Postoperative cognitive complications are associated with substantial morbidity and mortality. Ketamine has been suggested to have neuroprotective effects in various settings. This systematic review evaluates the effects of intraoperative ketamine administration on postoperative delirium and postoperative cognitive dysfunction (POCD).

Methods

Medline, Embase and Central were searched to 4 March 2018 without date or language restrictions. We considered randomised controlled trials (RCTs) comparing intraoperative ketamine administration versus no intervention in adults undergoing surgery under general anaesthesia. Primary outcomes were postoperative delirium and POCD. Non‐cognitive adverse events, mortality and length of stay were considered as secondary outcomes. Data were independently extracted. The quality of the evidence (GRADE approach) was assessed following recommendations from the Cochrane collaboration. Risk ratios were calculated for binary outcomes, mean differences for continuous outcomes. We planned to explore the effects of age, specific anaesthesia regimen, depth of anaesthesia and intraoperative haemodynamic events through subgroup analyses.

Results

Six RCTs were included. The incidence of postoperative delirium did not differ between groups (4 trials, 557 patients, RR 0.83, 95% CI [0.25, 2.80]), but patients receiving ketamine seemed at lower risk of POCD (3 trials, 163 patients, RR 0.34, 95% CI [0.15, 0.73]). However, both analyses presented limitations. Therefore, the quality of the evidence (GRADE) was deemed low (postoperative delirium) and very low (POCD).

Conclusion

The effect of ketamine on postoperative delirium remains unclear but its administration may offer some protection towards POCD. Large, well‐designed randomised trials are urgently needed to further clarify the efficacy of ketamine on neurocognitive outcomes.

     

Early benefit of preserved cognitive function is not sustained at one-year after cardiac surgery: a longitudinal follow-up of the randomized controlled trial

Purpose

Recently, we showed that processing of shed blood with a continuous-flow cell saver during cardiopulmonary bypass resulted in a clinically significant reduction in postoperative cognitive decline (POCD) six weeks after coronary artery bypass graft (CABG) surgery. The current study examined if the early benefit of reduced POCD was sustained in the same patient population at one-year follow-up.

Methods

One hundred seventy patients (cell saver group, n?=?84; controls, n?=?86) underwent neuropsychological testing at baseline and one year after surgery. The raw scores for each test were converted to Z-scores, and a combined Z-score of ten main variables was then calculated for each study group.

Results

Postoperative cognitive decline was present in 16 of 84 (19%) patients in the cell saver group (95% confidence interval [CI], 10.8 to 27.2) vs 15 of 86 (17.4%) patients in the control group (95% CI, 9.6 to 25.2) (P?=?0.786). Six of the 15 patients in the control group with POCD at six weeks had the impairment at one year and five did not; four were lost to follow-up. Three of the six cell saver patients with POCD at six weeks still had impairment at one year, two did not, and one was not tested. Thirteen (15.4%) and nine (10.5%) patients in the cell saver and control groups, respectively, developed new POCD which was not evident at the six-week follow-up.

Conclusions

The short-term preservation of cognitive function in elderly patients using the cell saver management strategy did not translate into a long-term benefit one year after CABG surgery. The presence of progressing cerebrovascular disease may be responsible for the long-term cognitive decline. (ClinicalTrials.gov number, NCT00193999).     

Apolipoprotein E e4 allele does not increase the risk of early postoperative delirium after major surgery

Background

A relationship between patients with a genetic predisposition to and those who develop postoperative delirium has not been yet determined. The aim of this study was to determine whether there is an association between apolipoprotein E epsilon 4 allele (APOE4) and delirium after major surgery.

Methods

Of 230 intensive care patients admitted to the post anesthesia care unit (PACU) over a period of 3?months, 173 were enrolled in the study. Patients?? demographics and intra- and postoperative data were collected. Patients were followed for the development of delirium using the Intensive Care Delirium Screening Checklist, and DNA was obtained at PACU admission to determine apolipoprotein E genotype.

Results

Fifteen percent of patients developed delirium after surgery. Twenty-four patients had one copy of APOE4. The presence of APOE4 was not associated with an increased risk of early postoperative delirium (4% vs. 17%; P?=?0.088). The presence of APOE4 was not associated with differences in any studied variables. Multivariate analysis identified age [odds ratio (OR) 9.3, 95% confidence interval (CI) 2.0?C43.0, P?=?0.004 for age ??65?years), congestive heart disease (OR 6.2, 95% CI 2.0?C19.3, P?=?0.002), and emergency surgery (OR 59.7, 95% CI 6.7?C530.5, P?<?0.001) as independent predictors for development of delirium. The Simplified Acute Physiology Score II (SAPS II) and The Acute Physiology and Chronic Health Evaluation II (APACHE II) were significantly higher in patients with delirium (P?<?0.001 and 0.008, respectively). Hospital mortality rates of these patients was higher and they had a longer median PACU stay.

Conclusions

Apolipoprotein e4 carrier status was not associated with an increased risk for early postoperative delirium. Age, congestive heart failure, and emergency surgery were independent risk factors for the development of delirium after major surgery.     

Delirium following vascular surgery: increased incidence with preoperative β-blocker administration

Purpose

To determine if there is an association between perioperative administration of beta-blockers and postoperative delirium in patients undergoing vascular surgery.

Methods

After Institutional Review Board approval, data were retrospectively collected on patients who underwent vascular surgery in an academic hospital during the period January 2006 to January 2007. Patients with preoperative altered level of consciousness, carotid endarterectomy, or discharge within 24 h of surgery were excluded from the study. Identification of delirium was based on evaluation of the level of consciousness with the NEECHAM Confusion Scale and/or a chart-based instrument for delirium. Multivariable logistic regression analysis was used to identify independent perioperative predictors of postoperative delirium. Beta-blockers were tested for a potential effect.

Results

The incidence of postoperative delirium was 128/582 (22%). Independent predictors included age (OR 1.04, 95% CI [1.02–1.07]), history of cerebrovascular accident/transient ischemic attack (OR 2.64, 95% CI [1.57–4.55]), and depression (OR 3.56, 95% CI [1.53–8.28]). Open aortic reconstruction was associated with an OR of 5.34, 95% CI (2.54–11.2) and amputation with an OR of 4.66, 95% CI (1.96–11.09). Preoperative beta-blocker administration increased the odds of postoperative delirium 2.06 times (95% CI [1.18–3.6]). Statin administration reduced the odds of delirium by 44% (95% CI [0.37–0.88]). The model was reliable (Hosmer–Lemeshow test, P = 0.72) and discriminative (area under the receiver operating characteristic [ROC] curve = 0.729).

Conclusions

Preoperative administration of beta-blockers is associated with an increased risk of postoperative delirium after vascular surgery. Conversely, preoperative statin administration is associated with a lower risk of postoperative delirium. A randomized prospective controlled trial is required to validate these findings.     

Incidence and Risk Factors of Postoperative Delirium in Patients with Esophageal Cancer

Background

Postoperative delirium is a common complication after major surgery and is characterized by acute confusion with fluctuating consciousness. The aim of this study was to investigate the incidence and risk factors of postoperative delirium in patients with esophageal cancer.

Methods

We conducted a retrospective cohort analysis of 306 consecutive patients who had undergone an esophagectomy at Keio University Hospital from January 1998 to December 2009. All data were assessed by psychiatrists, and delirium was diagnosed according to criteria of the Diagnostic and Statistical Manual Disorder, fourth edition. Univariate and multivariate analyses were performed.

Results

Postoperative delirium developed in 153 (50.0?%) of 306 patients. One hundred fourteen (37.3?%) of the 306 patients required psychoactive medication for symptoms associated with delirium. Univariate analyses showed that older age, male gender, additional flunitrazepam for sedation in intensive care unit (ICU) after surgery, longer periods of time under mechanical ventilation after surgery, longer ICU stays, occurrence of postoperative complications, and longer hospital stays were significantly associated with postoperative delirium. Multivariate analysis revealed that development of delirium was linked to older age, additional flunitrazepam in ICU, and occurrence of postoperative complication.

Conclusions

The development of postoperative delirium in patients with esophageal cancer is a problem that cannot be ignored. Our results suggest that the risk of developing delirium is associated with older age, use of flunitrazepam in ICU, and postoperative complications.     

Haloperidol prophylaxis does not prevent postoperative delirium in elderly patients: a randomized,open-label prospective trial

Purpose

Postoperative delirium is the most common postoperative complication in the elderly. The purpose of this study was to evaluate the safety and effectiveness of the preventive administration of low-dose haloperidol on the development of postoperative delirium after abdominal or orthopedic surgery in elderly patients.

Subjects

A total of 119 patients aged 75 years or older who underwent elective surgery for digestive or orthopedic disease were included in this study.

Methods

Patients were divided into those who did (intervention group, n = 59) and did not (control group, n = 60) receive 2.5 mg of haloperidol at 18:00 daily for 3 days after surgery; a randomized, open-label prospective study was performed on these groups. The primary endpoint was the incidence of postoperative delirium during the first 7 days after the operation.

Results

The incidence of postoperative delirium in all patients was 37.8 %. No side effects involving haloperidol were noted; however, the incidences of postoperative delirium were 42.4 and 33.3 % in the intervention and control groups, respectively, which were not significantly different (p = 0.309). No significant effect of the treatment was observed on the severity or persistence of postoperative delirium.

Conclusions

The preventive administration of low-dose haloperidol did not induce any adverse events, but also did not significantly decrease the incidence or severity of postoperative delirium or shorten its persistence.     

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.     

Hippocampal volume reduction in elderly patients at risk for postoperative cognitive dysfunction

Purpose

Postoperative cognitive dysfunction (POCD) is a formidable public health issue, which would not only affect the quality of life among elderly patients but also lead to pulmonary infection and increased mortality. While, there is a lack of an effective indicator in predicting POCD. As one pivotal part of the limbic system in brain, hippocampus is associated with cognitive function. Hippocampal atrophy could indicate the degree of changes in cognitive function.

Methods

Forty-one ASA II or III patients (23 male, 18 female) aged ≥65 years undergoing open gastrointestinal tract surgery were enrolled in this study. MRI was performed to measure the volume of hippocampal formation before surgery and the results were standardized according to individual intracranial volume. All patients underwent a battery of neuropsychological tests including sensitive tests on the Wechsler adult memory scale and Wechsler adult intelligence scale, trail making test and the grooved pegboard test. We used the Z score to identify POCD as recommended by ISPOCD. All patients were then divided into POCD group and non-POCD group according to the results of the neuropsychological tests. The results of the tests were correlated with the volume of hippocampal formation measured by MRI. The value of MRI measurement of hippocampal volume in predicting POCD was analyzed. Multivariate linear correlation analyses of compositive Z score using potential contributing factors such as age, duration of anesthesia, education and hippocampal volume was carried out.

Results

Thirty-six patients completed the whole battery of neuropsychological tests after surgery. Thirteen of the 36 patients were found to have POCD (36 %) on the postoperative 4th day. The hippocampal volume was significantly smaller in POCD group (4.75 ± 0.23) than in non-POCD group (5.06 ± 0.31). Hippocampal volume had great influence on Z score, and had negative correlation with Z score.

Conclusion

The MRI measurement of hippocampal volume is suggested to be valuable as a predictor of POCD in the elderly.     

Changes in plasma and cerebrospinal fluid biomarkers in aged patients with early postoperative cognitive dysfunction following total hip-replacement surgery

Purpose

We hypothesized that different patterns of biomarkers of brain injury and inflammation exist in aged patients with postoperative cognitive dysfunction (POCD) after total hip-replacement with spinal anesthesia.

Methods

Eighty-three patients older than 65 years undergoing elective total hip-replacement surgery were enrolled in this prospective observational study. The CSF levels of Tau, phosphorylated-tau (pTau), amyloidβ1–42 (Aβ1–42), Tau/Aβ1–42, pTau/Aβ1–42, BDNF, IL-6, and IL-1β were measured preoperatively. Perioperative plasma levels of IL-1β, IL-6, brain-derived neurotrophic factor (BDNF), C-reactive protein (CRP), and malonaldehyde (MDA) as well as neurocognitive tests were determined preoperatively and seven days postoperatively.

Results

Sixty-one patients completed both the CSF and blood samples collection and the neurocognitive tests. POCD occurred in 24.6 % of patients at seven days after surgery. Patients with POCD had significantly higher IL-1β, Tau/Aβ1–42, pTau/Aβ1–42, and a lower level of Aβ1–42 in CSF when compared with the Non-POCD group (P < 0.05). Furthermore, POCD patients displayed significantly higher plasma levels of MDA when compared with Non-POCD patients at seven days after surgery (P < 0.05). There was no difference in preoperative CSF levels of Tau, IL-6, and pTau as well as plasma levels of IL-1β, IL-6, BDNF and CRP between POCD and Non-POCD groups (P > 0.05).

Conclusion

The POCD patients were associated with higher postoperative plasma levels of MDA, and higher IL-1β and lower Aβ1–42 levels in preoperative CSF that might predispose the development of POCD in aged patients following total hip-replacement surgery with spinal anesthesia.     

Intraoperative cerebral oximetry-based management for optimizing perioperative outcomes: a meta-analysis of randomized controlled trials

Purpose

Although evidence from observational studies in a variety of clinical settings supports the utility of cerebral oximetry as a predictor of outcomes, prospective clinical trials thus far have reported conflicting results. This systematic review and meta-analysis was designed to evaluate the influence of management associated with intraoperative cerebral oximetry on postoperative outcomes. The primary outcome was postoperative cognitive dysfunction (POCD), with secondary outcomes that included postoperative delirium, length of intensive care unit (ICU) stay, and hospital length of stay (LOS).

Source

After searching the PubMed, EMBASE, Cochrane Library, Scopus, and Google Scholar databases, all randomized controlled trials (RCTs) assessing the impact of intraoperative cerebral oximetry-guided management on clinical outcomes following surgery were identified.

Principal findings

Fifteen RCTs comprising 2,057 patients (1,018 in the intervention group and 1,039 in control group) were included. Intraoperative management guided by the use of cerebral oximetry was associated with a reduction in the incidence of POCD (risk ratio [RR] 0.54; 95% confidence interval [CI], 0.33 to 0.90; P = 0.02; I² = 85%) and a significantly shorter length of ICU stay (standardized mean difference [SMD], ?0.21 hr; 95% CI, ?0.37 to ?0.05; P = 0.009; I² = 48%). In addition, overall hospital LOS (SMD, ?0.06 days; 95% CI, ?0.18 to 0.06; P = 0.29; I² = 0%) and incidence of postoperative delirium (RR, 0.69; 95% CI, 0.36 to 1.32; P = 0.27; I² = 0%) were not impacted by the use of intraoperative cerebral oximetry.

Conclusions

Intraoperative cerebral oximetry appears to be associated with a reduction in POCD, although this result should be interpreted with caution given the significant heterogeneity in the studies examined. Further large (ideally multicentre) RCTs are needed to clarify whether POCD can be favourably impacted by the use of cerebral oximetry-guided management.

     

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.     

Methohexital zur Analgosedierung bei beatmeten Intensivpatienten

Background

Delirium is defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR) as a potentially reversible disturbance of consciousness and a change of cognition caused by a medical condition, drug intoxication, or medication side effect. Delirium affects up to 80?% of intensive care unit (ICU) patients and is associated with increased morbidity and mortality. One risk factor for development of delirium in ventilated intensive care unit patients is sedation. The German S3 guidelines on “Analgesie, Sedierung und Delirmanagement in der Intensivmedizin” (analgesia, sedation and delirium management in intensive care medicine) of the DGAI (German Society for Anesthesiology and Intensive Care Medicine) and the DIVI (German Interdisciplinary Association for Intensive Care and Emergency Medicine) recommend midazolam and propofol for sedation, although both drugs are associated with a high incidence of delirium.

Aim

Within the framework of this study the question arose whether the barbiturate methohexital could be associated with a lower incidence of delirium in comparison to midazolam or propofol in analgosedated and ventilated ICU patients.

Material and methods

This was a prospective nonrandomized observational cohort study in a mixed medical surgical intensive care unit. Patients ventilated within 72 h after admittance were consecutively allocated to either propofol/remifentanil versus methohexital/remifentanil (expected ventilation duration ≤?7 days) or midazolam/fentanyl versus methohexital/fentanyl (expected ventilation duration >?7 days) by the attending senior consultant anesthetist at the time of admission and/or intubation. Primary endpoint was delirium at any time during the ICU stay. Delirium was checked every 8 h by ICU nurses using the intensive care delirium screening checklist (ICDSC), with delirium defined as ICDSC ≥?4 points. Before evaluation of the ICDSC the Richmond agitation sedation scale (RASS) score and the visual analogue scale for pain (VAS target ≤?4) were measured. To assure reliable evaluation of the ICDSC, the RASS score of the patient at the time of evaluation had to be ≥???2. Assuming an incidence of delirium in the midazolam group of 70?% and in the methohexital group of 35?%, 16 patients were needed each in the midazolam/fentanyl and the methohexital/fentanyl cohorts (p?=?0.05, β =?0.1). Assuming an incidence of delirium in the propofol group of 50?% and in the methohexital group again of 35?%, 94 patients were needed in the propofol/remifentanil and methohexital/remifentanil groups, respectively (p?=?0.05, β =?0.1).

Results

A total of 222 patients were evaluated, 34 in the methohexital vs. midazolam group and 188 in the methohexital vs. propofol group. Out of 16 patients sedated with midazolam, 15 developed delirium (94?%) in contrast to only 5 out of 18 patients sedated with methohexital (28?%). Thus compared to midazolam the sedation with methohexital reduced the incidence of delirium by 66?% (p?<?0.001) corresponding to a number needed to treat (NNT) of 1.5. Out of 94 patients in the propofol/remifentanil group, 64 developed delirium (68?%) in contrast to only 23 out of 94 in the methohexital/remifentanil group (24?%). Thus compared to propofol the sedation with methohexital reduced the incidence of delirium by 44?% (p?<?0.001), corresponding to an NNT of 2.5.

Conclusion

Sedation with methohexital compared to midazolam or propofol reduced the incidence of delirium by more than 50?% in ventilated ICU patients.     

Postoperative delirium: risk factors and management: Continuing Professional Development

Purpose

Postoperative delirium often remains undiagnosed and therefore untreated. The purpose of this continuing professional development module is to identify patients at high risk of developing delirium following non-cardiac surgery and to provide tools to aid in the diagnosis of delirium at the bedside. Optimal prevention and treatment strategies are recommended.

Principal findings

Delirium is characterized by an acute onset and a fluctuating course, inattention, disorganized thinking and an altered level of consciousness, and occurs in up to 40% of patients in the perioperative period. The pathophysiology of delirium is multifactorial, but it is believed to be related to inflammation, altered neurotransmission, and stress in the patient who has had surgery. Acetylcholine and dopamine appear to play a significant role. There is an increased risk of a poor outcome in patients who develop delirium, including a longer hospital stay and death. Surgical and patient factors play a significant role in predicting who will subsequently develop delirium. Prevention is much more effective than treatment in the management of delirium. The most effective prevention strategies include proactive geriatric assessment and care of the patient on a geriatrics surgical ward as well as prophylactic low-dose antipsychotic agents. From an anesthetic perspective, evidence in some surgical populations would support the use of regional techniques and minimal sedation. If delirium develops, treatment with low-dose oral antipsychotics appears to be most effective.

Conclusions

Delirium is a serious condition that must be recognized early and treated promptly to minimize deleterious outcomes. In order to institute prevention strategies and treat the condition effectively when it occurs, the anesthesiologist must be vigilant in identifying patients at risk and in screening for this condition.     

A brief review of practical preoperative cognitive screening tools

Purpose

Preoperative cognitive impairment is associated with the development of postoperative delirium, a common and consequential complication of major surgery in older patients. Screening for cognitive impairment should become a routine part of the preoperative evaluation of older patients; however, its implementation is hampered by limited clinical time and resources. The objective of this review was to identify cognitive screening tools that could be easily incorporated into the evaluation of older patients before major surgery.

Search strategy

Using strict inclusion and exclusion criteria, we searched PubMed over a 15-year period for short and simple cognitive screening tools. In addition, we reviewed studies that examined these cognitive screening tools in a perioperative environment.

Search results

We identified six cognitive screening tools that could each be administered in 2.5 min or less. Among the tools, sensitivity for cognitive impairment ranged from 79-99%, while specificity ranged from 70-98%. Only one (Mini-Cog) of the six tools we identified had been tested in a perioperative environment.

Conclusions

Incorporating a cognitive screening assessment into the preoperative evaluation of older patients is feasible. More research is needed to validate cognitive screening tools in the perioperative setting.     

Risk factors for delirium after cardiac surgery: a historical cohort study outlining the influence of cardiopulmonary bypass

Purpose

Cardiopulmonary bypass (CPB) induces a significant inflammatory response that may increase the risk for delirium. We hypothesized that exposure to CPB during coronary artery bypass grafting (CABG) surgery would correlate with an increased risk of delirium.

Methods

We reviewed clinical data from two databases at our medical centre - the Cardiac Surgery Perioperative Outcomes Database and the Society of Thoracic Surgeons Database. Patients undergoing elective CABG surgery (on-pump and off-pump) from November 1, 2009 to September 30, 2015 were included in the study. Delirium was defined as any postoperative positive Confusion Assessment Method for the Intensive Care Unit exam during the intensive care unit stay. We performed logistic regression to isolate the association between CPB exposure and delirium adjusted for predetermined risk factors and potential confounders.

Results

During the study period, 2,280 patients underwent elective CABG surgery, with 384 patients (16.9%) exposed to CPB. Delirium was diagnosed in 451 patients (19.8%). Exposure to CPB showed a significant independent association with delirium. Patients exposed to CPB for 142 min (90^th percentile of CPB duration) vs those exposed for 54 min (10^th percentile) had an adjusted relative risk (RR) of delirium of 2.18 (95% confidence interval [CI], 1.39 to 3.07; P = 0.002) vs a RR of 1.51 (95% CI, 0.92 to 2.29; P = 0.10), respectively.

Conclusions

The use and duration of cardiopulmonary bypass were associated with an increased risk of delirium in patients undergoing CABG surgery.

Trial registration

www.clinicaltrials.gov, NCT02548975. Registered 4 September 2015.

     

Fast-track surgery decreases the incidence of postoperative delirium and other complications in elderly patients with colorectal carcinoma

Objective

This study aims to investigate the role of fast-track surgery in preventing the development of postoperative delirium and other complications in elderly patients with colorectal carcinoma.

Methods

A total of 240 elderly patients with colorectal carcinoma (aged ≥70 years) undergoing open colorectal surgery was randomly assigned into two groups, in which the patients were managed perioperatively either with traditional or fast-track approaches. The length of hospital stay (LOS) and time to pass flatus were compared. The incidence of postoperative delirium and other complications were evaluated. Serum interleukin-6 (IL-6) levels were determined before and after surgery.

Results

The LOS was significantly shorter in the fast-track surgery (FTS) group than that in the traditional group. The recovery of bowel movement (as indicated by the time to pass flatus) was faster in the FTS group. The postoperative complications including pulmonary infection, urinary infection and heart failure were significantly less frequent in the FTS group. Notably, the incidence of postoperative delirium was significantly lower in patients with the fast track therapy (4/117, 3.4 %) than with the traditional therapy (15/116, 12.9 %; p?=?0.008). The serum IL-6 levels on postoperative days 1, 2, and 3 in patients with the fast-track therapy were significantly lower than those with the traditional therapy (p?<?0.001).

Conclusions

Compared to traditional perioperative management, fast-track surgery decreases the LOS, facilitates the recovery of bowel movement, and reduces occurrence of postoperative delirium and other complications in elderly patients with colorectal carcinoma. The lower incidence of delirium is at least partly attributable to the reduced systemic inflammatory response mediated by IL-6.     

Delirium in older people after proximal femoral fracture repair: Role of a preoperative screening cognitive test

Objective

Preoperative cognitive impairment has been identified as a major risk factor for postoperative delirium in older people. The aim of this study was to evaluate whether a validated and rapid screening cognitive test — COgnitive Disorder EXamination (CODEX) — performed preoperatively before proximal femoral fracture repair, was associated with a risk of postoperative delirium.

Study design

We performed an observational prospective cohort study in orthopedic surgery department of a French hospital.

Patients

We included patients aged 70 years or older undergoing proximal femoral fracture repair and who were free of known dementia and delirium at the preoperative phase.

Methods

Before surgery, the anesthesiologist realized the CODEX based on three-word recall test, simplified clock drawing and if one of these tasks was abnormal, spatial orientation was assessed. Delirium was routinely sought on postoperative day 3 (D3) using the Confusion Assessment Method by the geriatrician.

Results

Among the 52 included patients, seven (13.5%) had delirium on D3. All seven patients were among the 25 patients with abnormal CODEX results. None of the 27 patients with normal CODEX results had postoperative delirium. Abnormal CODEX was significantly associated with the risk of postoperative delirium in univariate analysis and after adjustment for age (odds ratio [OR]: 13.33; 95% confidence interval, [95%CI]: 1.85 ± ∞; P < 0.003).

Conclusion

Abnormal preoperative rapid screening test CODEX is independently associated with postoperative delirium in older people undergoing hip fracture surgery and free of known dementia.     

Hospital administrative database underestimates delirium rate after cardiac surgery

Purpose

Administrative electronic databases are highly specific for postoperative complications, but they lack sensitivity. The objective of this study was to determine the incidence of delirium after cardiac surgery using a targeted prospectively collected dataset and to compare the findings with the incidence of delirium in the same cohort of patients identified in a hospital administrative database.

Methods

Following Research Ethics Board approval, we compared delirium rates in a prospectively collected data research database with delirium rates in the same cohort of patients in an administrative hospital database where delirium was identified from codes entered by coding and abstracting staff. Every 12 hr postoperatively, delirium was assessed with a Confusion Assessment Method in the Intensive Care Unit. The administrative database contained the International Classification of Diseases version 10 (ICD-10) codes for patient diagnoses. The ICD-10 codes were extracted from the administrative database for each patient in the research database and were checked for the presence of the ICD-10 code for delirium.

Results

Data from a cohort of 1,528 patients were analyzed. Postoperative delirium was identified in 182 (11.9%) patients (95% confidence interval [CI], 10.3-13.5%) in the research dataset and 46 (3%) patients (95% CI, 2.2-3.8%) in the administrative dataset (P < 0.001). Thirteen (0.85%) patients who were coded for delirium in the administrative database were not identified in the research dataset. The median onset of postoperative delirium in these patients was significantly delayed (4 [3-9] days) compared with patients identified by both datasets (2 [1-9] days) and compared with patients from the research database only (1 [1-14] days) (P = 0.007).

Conclusion

Postoperative delirium rates after cardiac surgery are underestimated by the hospital administrative database.