Regional cerebral blood flow in delirium patients

Predictiveness of preoperative laboratory values for postoperative delirium

Background

Postoperative delirium (POD) is a common postoperative complication, especially in patients over 60 years, with an incidence ranging from 15% to 50%. In most cases, POD manifests in the first 5 days after surgery. Multiple contributing risk factors for POD have been detected. Besides the predisposing factors such as higher age, cognitive impairment, high blood pressure, atrial fibrillation, and past stroke, pathophysiological mechanisms like neuroinflammation are also considered as contributing factors.

Methods

In a subanalysis of the "PRe- Operative  Prediction of postoperative  DElirium by appropriate  SCreening" (PROPDESC) study, the preoperative laboratory values of sodium, potassium, total protein, hemoglobin concentration (Hgb), and white blood cells as well as the biomarkers creatinine, HbA1c, NT-pro-BNP, high sensitive Troponin T (hsTnT), and C-reactive protein (CRP) were assessed to investigate a possible relationship to the occurrence of POD.

Results

After correction for age, physical status classification, surgery risk after Johns Hopkins, and operative discipline (cardiac surgery vs. noncardiac surgery), male patients with a Hgb <13 g/dL had significantly higher odds for POD (p = 0.025). Furthermore, patients with CRP ≥ 10 mg/L, HbA1c value ≥ 8.5% as well as patients with hypernatraemia (>145 mmol/L) presented significantly higher odds to develop POD (p = 0.011, p < 0.001, and p = 0.021, respectively). A raised (>14-52 ng/L) or high (>52 ng/L) hsTnT value was also associated with a significantly higher chance for POD compared to the patient group with hsTnT <14 ng/L (p < 0.001 and p = 0.016, respectively).

Conclusions

Preoperative Hgb, CRP, HbA1c, sodium, and hsTnT could be used to complement and refine the preoperative screening for patients at risk for POD. Further studies should track these correlations to investigate the potential of targeted POD protection and enabling hospital staff to initiate POD-preventing measures in time.

Acute encephalopathy in the ICU: a practical approach

PURPOSE OF REVIEW

Acute encephalopathy (AE) - which frequently develops in critically ill patients with and without primary brain injury - is defined as an acute process that evolves rapidly and leads to changes in baseline cognitive status, ranging from delirium to coma. The diagnosis, monitoring, and management of AE is challenging. Here, we discuss advances in definitions, diagnostic approaches, therapeutic options, and implications to outcomes of the clinical spectrum of AE in ICU patients without primary brain injury.

RECENT FINDINGS

Understanding and definitions of delirium and coma have evolved. Delirium is a neurocognitive disorder involving impairment of attention and cognition, usually fluctuating, and developing over hours to days. Coma is a state of unresponsiveness, with absence of command following, intelligible speech, or visual pursuit, with no imaging or neurophysiological evidence of cognitive motor dissociation. The CAM-ICU(-7) and the ICDSC are validated, guideline-recommended tools for clinical delirium assessment, with identification of clinical subtypes and stratification of severity. In comatose patients, the roles of continuous EEG monitoring and neuroimaging have grown for the early detection of secondary brain injury and treatment of reversible causes.

SUMMARY

Evidence-based pharmacologic treatments for delirium are limited. Dexmedetomidine is effective for mechanically ventilated patients with delirium, while haloperidol has minimal effect of delirium but may have other benefits. Specific treatments for coma in nonprimary brain injury are still lacking.

The Thalamus in Perioperative Neurocognitive Disorders

Thalamus function and structure are known predictors of individual differences in the risk of age-related neurocognitive disorders (NCD), such as dementia. However, to date, little is known about their role in the perioperative setting. Here, we provide a narrative review of brain-imaging studies of preoperative and postoperative thalamus scanning parameters associated with risks of developing perioperative NCD, such as postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) during the postoperative phase. These findings are discussed in light of the concept of reserve capacity.

Prognostic significance of delirium in patients with heart failure: a systematic review and meta-analysis

Background

Delirium is a common symptom of heart failure (HF) and is associated with increased mortality, prolonged hospital stays, and heightened medical costs. The impact of delirium on the prognosis of HF patients is currently controversial. Therefore, we conducted a meta-analysis to evaluate the prognostic significance of delirium in HF.

Methods

Relevant articles were systematically searched in PubMed, Cochrane Library, Web of Science, and Embase based on the PRISMA guidelines. Studies that reported mortality and hospitalization-related outcomes in HF patients with or without delirium using raw or adjusted hazard ratio (HR) and odds ratio (OD) were included. Meta-analysis was then performed to evaluate the effect of delirium in HF patients. Outcomes of interest were all-cause mortality and events of the hospitalization.

Results

Of the 1,501 studies identified, 7 eligible studies involving 12,830,390 HF patients (6,322,846 males and 6,507,544 females) were included in the meta-analysis. There were 91,640 patients with delirium (0.71%) and 12,738,750 patients without delirium (99.28%). HF patients with delirium had higher OR for in-hospital mortality (1.95, 95% CI = 1.30-2.91, P = 0.135), higher pooled HR for 90-day mortality (2.64, 95% CI = 1.06-1.56, P = 0.215), higher pooled HR for 1-year mortality (2.08, 95% CI = 1.34-3.22, P = 0.004), and higher pooled HR for 30-day readmission rate (4.15, 95% CI = 2.85-6.04, P = 0.831) than those without delirium.

Conclusion

Current evidence suggests that combined delirium increases the risk of HF-related mortality and hospitalization-related outcomes in patients with HF. However, more research is needed to assess the impact of delirium on the prognosis of HF patients.

The possible role of gut microbiota dysbiosis in the pathophysiology of delirium in older persons

Delirium is a clinical syndrome characterized by an acute change in attention, awareness and cognition with fluctuating course, frequently observed in older patients during hospitalization for acute medical illness or after surgery. Its pathogenesis is multifactorial and still not completely understood, but there is general consensus on the fact that it results from the interaction between an underlying predisposition, such as neurodegenerative diseases, and an acute stressor acting as a trigger, such as infection or anesthesia. Alterations in brain insulin sensitivity and metabolic function, increased blood-brain barrier permeability, neurotransmitter imbalances, abnormal microglial activation and neuroinflammation have all been involved in the pathophysiology of delirium. Interestingly, all these mechanisms can be regulated by the gut microbiota, as demonstrated in experimental studies investigating the microbiota-gut-brain axis in dementia. Aging is also associated with profound changes in gut microbiota composition and functions, which can influence several aspects of disease pathophysiology in the host. This review provides an overview of the emerging evidence linking age-related gut microbiota dysbiosis with delirium, opening new perspectives for the microbiota as a possible target of interventions aimed at delirium prevention and treatment.

General Anesthesia Versus Regional Anesthesia in the Elderly Patients Undergoing Hip Fracture Surgeries: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Surgery is the preferred treatment option for the elderly patients with hip fractures. However, the choice of general anesthesia (GA) or regional anesthesia (RA) remains controversial. The quality of evidence has further improved with the advent of several high-quality randomized clinical trials (RCTs) in the last two years. The purpose of this study was to compare the clinical outcomes of two anesthetic techniques in elderly patients undergoing hip fracture surgeries.

METHODS

Eligible studies were identified from PubMed/MEDLINE, Web of Science, Scopus, EMBASE and reference lists from January 2000 to June 2022 in this current systematic review and meta-analysis. The outcomes included the surgery-related outcomes (duration of surgery, duration of anesthesia, intraoperative blood loss and number of transfusions) and postoperative outcomes (30-day mortality, postoperative delirium,cardiovascular events and other complications).

RESULTS

A total of 10 RCTs were included, and a total of 3594 patients were analyzed. RA was associated with shorter duration of surgery, shorter length of hospital stays and less intraoperative blood loss compared to GA. There were no significant differences between the two groups in the number of blood transfusions, duration of anesthesia, 30-day mortality or postoperative delirium.

CONCLUSIONS

Our pooled analysis identified no significant differences in terms of the safety between RA and GA, while RA reduces intraoperative blood loss, length of hospital stays and duration of surgery. These results suggest that RA appears to be preferable for the elderly patients with hip fractures.

Regional cerebral hypometabolism on 18F-FDG PET/CT scan in delirium is independent of acute illness and dementia

INTRODUCTION

Delirium is associated with new onset dementia and accelerated cognitive decline; however, its pathophysiology remains unknown. Cerebral glucose metabolism previously seen in delirium may have been attributable to acute illness and/or dementia. We aimed to statistically map cerebral glucose metabolism attributable to delirium.

METHODS

We assessed cerebral glucose metabolism using ¹⁸ F-fluorodeoxyglucose positron emission tomography (FDG-PET) in sick, older patients with and without delirium, all without clinical dementia (N = 20). Strict exclusion criteria were adopted to minimize the effect of established confounders on FDG-PET.

RESULTS

Patients with delirium demonstrated hypometabolism in the bilateral thalami and right superior frontal, right posterior cingulate, right infero-lateral anterior temporal, and left superior parietal cortices. Regional hypometabolism correlated with delirium severity and performance on neuropsychological testing.

DISCUSSION

In patients with acute illness but without clinical dementia, delirium is accompanied by regional cerebral hypometabolism. While some hypometabolic regions may represent preclinical Alzheimer's disease (AD), thalamic hypometabolism is atypical of AD and consistent with the clinical features that are unique to delirium.

External validation and comparison of two delirium prediction models in patients admitted to the cardiac intensive care unit

Background

No data is available on delirium prediction models in the cardiac intensive care unit (CICU), although preexisting delirium prediction models [PREdiction of DELIRium in ICu patients (PRE-DELIRIC) and Early PREdiction of DELIRium in ICu patients (E-PRE-DELIRIC)] were developed and validated based on a population admitted to the general intensive care unit (ICU). Therefore, we externally validated the usefulness of the PRE-DELIRIC and E-PRE-DELIRIC models and compared their predictive performance in patients admitted to the CICU.

Methods

A total of 2,724 patients admitted to the CICU were enrolled between September 2012 and December 2018. Delirium was defined as at least one positive Confusion Assessment Method for the ICU (CAM-ICU) which was screened at least once every 8 h. The PRE-DELIRIC value was calculated within 24 h of CICU admission, and the E-PRE-DELIRIC value was calculated at CICU admission. The predictive performance of the models was evaluated by using the area under the receiver operating characteristic (AUROC) curve, and the calibration slope was assessed graphically by plotting.

Results

Delirium occurred in 677 patients (24.8%) when the patients were assessed thrice daily until 7 days of the CICU stay. The AUROC curve for the prediction of delirium was significantly greater for PRE-DELIRIC values [0.84, 95% confidence interval (CI): 0.82–0.86] than for E-PRE-DELIRIC values (0.79, 95% CI: 0.77–0.80) [z score of −6.24 (p < 0.001)]. Net reclassification improvement for the prediction of delirium increased by 0.27 (95% CI: 0.21–0.32, p < 0.001). Calibration was acceptable in the PRE-DELIRIC model (Hosmer-Lemeshow p = 0.170) but not in the E-PRE-DELIRIC model (Hosmer-Lemeshow p < 0.001).

Conclusion

Although both models have good predictive performance for the development of delirium, even in critically ill cardiac patients, the performance of the PRE-DELIRIC model might be superior to that of the E-PRE-DELIRIC model. Further studies are required to confirm our results and design a specific delirium prediction model for CICU patients.

Delirium and its association with short-term outcomes in younger and older patients with acute heart failure

Younger patients (18 to 65 years old) are often excluded from delirium outcome studies. We sought to determine if delirium was associated with short-term adverse outcomes in a diverse cohort of younger and older patients with acute heart failure (AHF). We conducted a multi-center prospective cohort study that included adult emergency department patients with confirmed AHF. Delirium was ascertained using the Brief Confusion Assessment Method (bCAM). The primary outcome was a composite outcome of 30-day all-cause death, 30-day all-cause rehospitalization, and prolonged index hospital length of stay. Multivariable logistic regression was performed, adjusting for demographics, cognitive impairment without delirium, and HF risk factors. Older age (≥ 65 years old)*delirium interaction was also incorporated into the model. Odds ratios (OR) with their 95% confidence intervals (95%CI) were reported. A total of 1044 patients with AHF were enrolled; 617 AHF patients were < 65 years old and 427 AHF patients were ≥ 65 years old, and 47 (7.6%) and 40 (9.4%) patients were delirious at enrollment, respectively. Delirium was significantly associated with the composite outcome (adjusted OR = 1.64, 95%CI: 1.02 to 2.64). The older age*delirium interaction p-value was 0.47. In conclusion, delirium was common in both younger and older patients with AHF and was associated with poorer short-term outcomes in both cohorts. Younger patients with acute heart failure should be included in future delirium outcome studies.

Sepsis-Associated Encephalopathy: A Mini-Review of Inflammation in the Brain and Body

Sepsis is defined as a life-threatening multi-organ dysfunction triggered by an uncontrolled host response to infectious disease. Systemic inflammation elicited by sepsis can cause acute cerebral dysfunction, characterized by delirium, coma, and cognitive dysfunction, known as septic encephalopathy. Recent evidence has reported the underlying mechanisms of sepsis. However, the reasons for the development of inflammation and degeneration in some brain regions and the persistence of neuroinflammation remain unclear. This mini-review describes the pathophysiology of region-specific inflammation after sepsis-associated encephalopathy (SAE), clinical features, and future prospects for SAE treatment. The hippocampus is highly susceptible to inflammation, and studies that perform treatments with antibodies to cytokine receptors, such as interleukin-1β, are in progress. Future development of clinically applicable therapies is expected.

Delirium in intensive care: violence, loss and humanity

Delirium in intensive care is an altered state that can bring with it persecutory paranoias, and sometimes expressions of violence on the part of the patient; it can be deeply disturbing for the person experiencing it as well as for those around them. Although the impacts of delirium on patients' recovery and long-term mental health are well documented, qualitative research in this area remains rare. This article is derived from a narrative and musical study of the experience of delirium in hospital, undertaken better to understand the perspectives of people who have experienced delirium, as well as the healthcare professionals and family members who care for them. Data were collected in South Africa between 2015 and 2017. The study took the form of interviews and focus groups with a total of 15 participants, as well as periods of observation and audio recording in a hospital intensive care unit. Thematic and narrative analysis of the data were carried out alongside the composition of new music incorporating audio recordings from the study. Analysis suggested three key themes emerging from the data. First, the violence experienced and expressed by patients, both within delirious hallucination and in observable reality. Second, the interconnected losses undergone by patients in spaces of intensive care. Third, healthcare professionals' attempts to bring greater humanity into the potentially dehumanising space of intensive care. The results and discussion point to possible relationships between delirium and the working cultures and physical environment of intensive care, and may reinforce the need for sensitive and committed communication between healthcare professionals and patients.

Rapidly progressive brain atrophy in septic ICU patients: a retrospective descriptive study using semiautomatic CT volumetry

Background

Sepsis is often associated with multiple organ failure; however, changes in brain volume with sepsis are not well understood. We assessed brain atrophy in the acute phase of sepsis using brain computed tomography (CT) scans, and their findings’ relationship to risk factors and outcomes.

Methods

Patients with sepsis admitted to an intensive care unit (ICU) and who underwent at least two head CT scans during hospitalization were included (n = 48). The first brain CT scan was routinely performed on admission, and the second and further brain CT scans were obtained whenever prolonged disturbance of consciousness or abnormal neurological findings were observed. Brain volume was estimated using an automatic segmentation method and any changes in brain volume between the two scans were recorded. Patients with a brain volume change < 0% from the first CT scan to the second CT scan were defined as the “brain atrophy group (n = 42)”, and those with ≥ 0% were defined as the “no brain atrophy group (n = 6).” Use and duration of mechanical ventilation, length of ICU stay, length of hospital stay, and mortality were compared between the groups.

Results

Analysis of all 42 cases in the brain atrophy group showed a significant decrease in brain volume (first CT scan: 1.041 ± 0.123 L vs. second CT scan: 1.002 ± 0.121 L, t (41) = 9.436, p < 0.001). The mean percentage change in brain volume between CT scans in the brain atrophy group was –3.7% over a median of 31 days, which is equivalent to a brain volume of 38.5 cm³. The proportion of cases on mechanical ventilation (95.2% vs. 66.7%; p = 0.02) and median time on mechanical ventilation (28 [IQR 15–57] days vs. 15 [IQR 0–25] days, p = 0.04) were significantly higher in the brain atrophy group than in the no brain atrophy group.

Conclusions

Many ICU patients with severe sepsis who developed prolonged mental status changes and neurological sequelae showed signs of brain atrophy. Patients with rapidly progressive brain atrophy were more likely to have required mechanical ventilation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03828-7.

Predisposing and Precipitating Risk Factors for Delirium in Elderly Patients Admitted to a Cardiology Ward: An Observational Cohort Study in 1,042 Patients

Aim: Although the risk factors for delirium in general medicine are well-established, their significance in cardiac diseases remains to be determined. Therefore, we evaluated the predisposing and precipitating risk factors in patients hospitalized with acute and chronic heart disease.

Methods and Results: In this observational cohort study, 1,042 elderly patients (≥65 years) admitted to cardiology wards, 167 with and 875 without delirium, were included. The relevant sociodemographic and cardiac- and medical-related clusters were assessed by simple and multiple regression analyses and prediction models evaluating their association with delirium. The prevalence of delirium was 16.0%. The delirious patients were older (mean 80 vs. 76 years; p < 0.001) and more often institutionalized prior to admission (3.6 vs. 1.4%, p = 0.05), hospitalized twice as long (12 ± 10 days vs. 7 ± 7 days; p < 0.001), and discharged more often to nursing homes (4.8 vs. 0.6%, p < 0.001) or deceased (OR, 2.99; 95% CI, 1.53–5.85; p = 0.003). The most relevant risk factor was dementia (OR, 18.11; 95% CI, 5.77–56.83; p < 0.001), followed by history of stroke (OR, 6.61; 95% CI 1.35–32.44; p = 0.020), and pressure ulcers (OR, 3.62; 95% CI, 1.06–12.35; p = 0.040). The predicted probability for developing delirium was highest in patients with reduced mobility and institutionalization prior to admission (PP = 31.2%, p = 0.001). Of the cardiac diseases, only valvular heart disease (OR, 1.57; 95% CI, 1.01–2.44; p = 0.044) significantly predicted delirium. The patients undergoing cardiac interventions did not have higher rates of delirium (OR, 1.39; 95% CI 0.91–2.12; p = 0.124).

Conclusion: In patients admitted to a cardiology ward, age-related functional and cognitive impairment, history of stroke, and pressure ulcers were the most relevant risk factors for delirium. With regards to specific cardiological factors, only valvular heart disease was associated with risk for delirium. Knowing these factors can help cardiologists to facilitate the early detection and management of delirium.

Effect of hypertension and medication use regularity on postoperative delirium after maxillofacial tumors radical surgery

The incidence of postoperative delirium (POD) after maxillofacial tumors radical surgery is relatively high. There are a number of evidences showing the relationship between hypertension and decreased cerebral blood flow, as well as the relationship between cerebral ischemia and postoperative cognitive impairment. However, the impact of hypertension in the process of POD and related mechanisms remain unclear.

This study included 98 elderly patients who underwent maxillofacial tumors radical surgery in our hospital, from June 2020 to December 2020. We collected the general condition of patients and related research factors before surgery, and also collected related intraoperative factors. After that, we would follow up the patients for POD evaluation.

The incidence of POD in the hypertension group was 41%, compared with 12% in the nonhypertension group (P < 0.05). The incidence of POD in the irregular medication group was 62%, compared with 26% in the regular medication group (P < 0.05). Both hypertension (OR = 2.45, 95% CI = 1.11–5.72) and irregular medication use (OR = 2.35, 95% CI = 0.87–5.69) were independent risk factors for POD after this type of surgery in elderly patients.

Hypertension and medication use regularity are closely related to POD. This may be related to the delayed postoperative response caused by intraoperative cerebral ischemia.

Delirium, Cerebral Perfusion, and High-Frequency Vital-Sign Monitoring in the Critically Ill. The CONFOCAL-2 Feasibility Study

Rationale: Studies suggest that reduced cerebral perfusion may contribute to delirium development in the intensive care unit (ICU). However, evidence is limited because of factors including small sample size and limited inclusion of covariates.Objectives: To assess the feasibility of a multicenter prospective observational study using a multimodal data collection platform. Feasibility was assessed by enrollment, data-capture, and follow-up rates. The full study will aim to assess the association between noninvasively derived surrogate markers of cerebral perfusion, delirium development, and long-term cognitive outcomes in critically ill patients.Methods: Adult patients in the ICU were enrolled if they had shock and/or respiratory failure requiring invasive mechanical ventilation for >24 hours. For the first 72 hours, a near-infrared spectroscopic sensor was placed on the forehead to continuously monitor regional cerebral oxygenation (rSo₂) and high-frequency (1 Hz) vital signs were concurrently captured via an arterial line. Cerebral perfusion was estimated using three variables, including mean rSo₂, duration of disturbed autoregulation, and time/magnitude away from optimal mean arterial pressure (MAP). Patients were screened for delirium in the ICU and ward daily for up to 30 days. Cognitive function was assessed 3 and 12 months after ICU admission to identify cognitive impairment.Results: Fifty-nine patients were enrolled across four sites in 1 year. Data-capture rates varied across modalities but exceeded 80% for rSo₂, blood gas, and delirium data capture. Vital-sign capture and 3-month follow-up rates were lower at 53% and 55%, respectively. Eighty-three percent (49 of 59) of patients experienced delirium, with a median severity of 0.56 in the ICU. Mean physiological (±standard deviation) values were: rSo₂ (70.4% ± 7.0%), heart rate (83.9 ± 16.45 beats/min), MAP (76.4 ± 12.8 mm Hg), peripheral oxygenation saturation (96.5% ± 2.1%), proportion of recording time spent with disturbed autoregulation (10.1% ± 7.3%) and proportion of area under the curve outside optimal MAP (39.6% ± 22.4%). Thirty-two (54%) individuals had cerebral autoregulation curves where a targeted optimal MAP was identified. Barriers to data collection included missing vital-sign data and low follow-up rates.Conclusions: Given our current protocol, a multicenter study examining the association between cerebral oxygenation, delirium, and long-term cognitive impairment is not feasible. However, by performing an early assessment of feasibility, we identified strategies to increase capture rates to ensure success as the study begins the next phase of study recruitment.Clinical trial registered with clinicaltrials.gov (NCT03141619).

Edaravone attenuates sustained pial arteriolar vasoconstriction independently of the endothelial function after unclamping of an abdominal aorta in rabbits

Background

Cerebral blood flow (CBF) has direct impacts on the neuronal function and neurocognitive disorder. Oxidative stress from abdominal aortic surgery is important in the pathophysiology of CBF impairment. We investigated whether oxidative damage from abdominal aortic surgery is associated with reduced CBF and whether vascular endothelial dysfunction modifies these associations.

Methods

Rabbit closed cranial window preparation was used to measure changes in the pial arteriolar diameter after unclamping following abdominal aortic cross-clamping with an intravenous free radical scavenger, edaravone (control group, n=6; edaravone 10 μg/kg/min, n=6; 100 μg/kg/min, n=6). The pial vasodilatory responses to the topical application of acetylcholine (ACh) into the cranial window were investigated before abdominal aortic cross-clamping and after unclamping with the intravenous administration of edaravone (control group, n=6; edaravone 100 μg/kg/min, n=6).

Results

The aortic unclamping-induced vasoconstriction was significantly attenuated under the continuous infusion of edaravone at 100 μg/kg/min. The topical application of ACh after unclamping did not produce any changes in pial arteriolar responses in comparison to before aortic cross-clamping in the control or edaravone groups. The changes in the response to topical ACh after unclamping in the saline and edaravone groups did not differ to a statistically significant extent.

Conclusions

Free radicals during abdominal aortic surgery might have contracted cerebral blood vessels independently of the endothelial function in rabbits. The suppression of free radicals attenuated sustained pial arteriolar vasoconstriction after aortic unclamping. Thus, the free radical scavenger might have some brain protective effect that maintains the CBF independently of the endothelial function.

Why is delirium more frequent in the elderly?

An aging-related reduction in the brain's functional reserve may explain why delirium is more frequent in the elderly than in younger people insofar as the reserve becomes inadequate to cover the metabolic requirements that are critically increased by stressors. The aim of this paper is to review the normal aging-related changes that theoretically compromise complex mental activities, neuronal and synaptic densities, and the neurocomputational flexibility of the functional reserve. A pivotal factor is diminished connectivity, which is substantially due to the loss of synapses and should specifically affect association systems and cholinergic fibres in delirious patients. However, micro-angiopathy with impaired blood flow autoregulation, increased blood/brain barrier permeability, changes in cerebrospinal fluid dynamics, weakened mitochondrial performance, and a pro-inflammatory involution of the immune system may also jointly affect neurons and their synaptic assets, and even cause the progression of delirium to dementia regardless of the presence of co-existing plaques, tangles, or other pathological markers. On the other hand, the developmental growth in functional reserve during childhood and adolescence makes the brain increasingly resistant to delirium, and residual reserve can allow the elderly to recover. These data support the view that functional reserve is the variable that confronts stressors and governs the risk and intensity of and recovery from delirium. Although people of any age are at risk of delirium, the elderly are at greater risk because aging and age-dependent structural changes inevitably affect the brain's functional reserve.

The Use of Near-Infrared Spectroscopy and/or Transcranial Doppler as Non-Invasive Markers of Cerebral Perfusion in Adult Sepsis Patients With Delirium: A Systematic Review

Background:

Several studies have previously reported the presence of altered cerebral perfusion during sepsis. However, the role of non-invasive neuromonitoring, and the impact of altered cerebral perfusion, in sepsis patients with delirium remains unclear.

Methods:

We performed a systematic review of studies that used near-infrared spectroscopy (NIRS) and/or transcranial Doppler (TCD) to assess adults (≥18 years) with sepsis and delirium. From study inception to July 28, 2020, we searched the following databases: Ovid MedLine, Embase, Cochrane Library, and Web of Science.

Results:

Of 1546 articles identified, 10 met our inclusion criteria. Although NIRS-derived regional cerebral oxygenation was consistently lower, this difference was only statistically significant in one study. TCD-derived cerebral blood flow velocity was inconsistent across studies. Importantly, both impaired cerebral autoregulation during sepsis and increased cerebrovascular resistance were associated with delirium during sepsis. However, the heterogeneity in NIRS and TCD devices, duration of recording (from 10 seconds to 72 hours), and delirium assessment methods (e.g., electronic medical records, confusion assessment method for the intensive care unit), precluded meta-analysis.

Conclusion:

The available literature demonstrates that cerebral perfusion disturbances may be associated with delirium in sepsis. However, future investigations will require consistent definitions of delirium, delirium assessment training, harmonized NIRS and TCD assessments (e.g., consistent measurement site and length of recording), as well as the quantification of secondary and tertiary variables (i.e., Cox, Mxa, MAP_OPT), in order to fully assess the relationship between cerebral perfusion and delirium in patients with sepsis.

Delirium

Delirium, a syndrome characterized by an acute change in attention, awareness and cognition, is caused by a medical condition that cannot be better explained by a pre-existing neurocognitive disorder. Multiple predisposing factors (for example, pre-existing cognitive impairment) and precipitating factors (for example, urinary tract infection) for delirium have been described, with most patients having both types. Because multiple factors are implicated in the aetiology of delirium, there are likely several neurobiological processes that contribute to delirium pathogenesis, including neuroinflammation, brain vascular dysfunction, altered brain metabolism, neurotransmitter imbalance and impaired neuronal network connectivity. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) is the most commonly used diagnostic system upon which a reference standard diagnosis is made, although many other delirium screening tools have been developed given the impracticality of using the DSM-5 in many settings. Pharmacological treatments for delirium (such as antipsychotic drugs) are not effective, reflecting substantial gaps in our understanding of its pathophysiology. Currently, the best management strategies are multidomain interventions that focus on treating precipitating conditions, medication review, managing distress, mitigating complications and maintaining engagement to environmental issues. The effective implementation of delirium detection, treatment and prevention strategies remains a major challenge for health-care organizations globally.

Regional Metabolic Patterns of Abnormal Postoperative Behavioral Performance in Aged Mice Assessed by 1H-NMR Dynamic Mapping Method

Abnormal postoperative neurobehavioral performance (APNP) is a common phenomenon in the early postoperative period. The disturbed homeostatic status of metabolites in the brain after anesthesia and surgery might make a significant contribution to APNP. The dynamic changes of metabolites in different brain regions after anesthesia and surgery, as well as their potential association with APNP are still not well understood. Here, we used a battery of behavioral tests to assess the effects of laparotomy under isoflurane anesthesia in aged mice, and investigated the metabolites in 12 different sub-regions of the brain at different time points using proton nuclear magnetic resonance (1H-NMR) spectroscopy. The abnormal neurobehavioral performance occurred at 6 h and/or 9 h, and recovered at 24 h after anesthesia/surgery. Compared with the control group, the altered metabolite of the model group at 6 h was aspartate (Asp), and the difference was mainly displayed in the cortex; while significant changes at 9 h occurred predominantly in the cortex and hippocampus, and the corresponding metabolites were Asp and glutamate (Glu). All changes returned to baseline at 24 h. The altered metabolic changes could have occurred as a result of the acute APNP, and the metabolites Asp and Glu in the cortex and hippocampus could provide preliminary evidence for understanding the APNP process.

Experimental sepsis-associated encephalopathy is accompanied by altered cerebral blood perfusion and water diffusion and related to changes in cyclooxygenase-2 expression and glial cell morphology but not to blood-brain barrier breakdown

Sepsis-associated encephalopathy (SAE) refers to brain dysfunction, including delirium, occurs during severe infection and is associated with development of post-traumatic stress disorder. SAE has been proposed to be related to reduced cerebral blood flow (CBF), blood-brain barrier breakdown (BBB), white matter edema and disruption and glia cell activation, but their exact relationships remain to be determined. In the present work, we set out to study CBF using Arterial Spin Labeling (ASL) and grey and white matter structure with T2- and diffusion magnetic resonance imaging (dMRI) in rats with cecal ligation and puncture (CLP)-induced encephalopathy. Using immunohistochemistry, the distribution of the vasoactive prostaglandin-synthesizing enzyme cyclooxygenase-2 (COX-2), perivascular immunoglobulins G (IgG), aquaporin-4 (AQP4) and the morphology of glial cell were subsequently assessed in brains of the same animals. CLP induced deficits in the righting reflex and resulted in higher T2-weighted contrast intensities in the cortex, striatum and at the base of the brain, decreased blood perfusion distribution to the cortex and increased water diffusion parallel to the fibers of the corpus callosum compared to sham surgery. In addition, CLP reduced staining for microglia- and astrocytic-specific proteins in the corpus callosum, decreased neuronal COX-2 and AQP4 expression in the cortex while inducing perivascular COX-2 expression, but did not induce widespread perivascular IgG diffusion. In conclusion, our findings indicate that experimental SAE can occur in the absence of BBB breakdown and is accompanied by increased water diffusion anisotropy and altered glia cell morphology in brain white matter.

Association of Duration of Surgery With Postoperative Delirium Among Patients Receiving Hip Fracture Repair

IMPORTANCE

Postoperative delirium in older adults receiving hip fracture surgery is associated with morbidity and increased health care costs, yet little is known of potential modifiable factors that may help limit the risks.

OBJECTIVE

To use population-wide individual-level data on the duration of hip fracture surgery to determine whether prolonged surgical times and type of anesthesia are associated with an increased risk of postoperative delirium.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective population-based cohort study analyzed patients aged 65 years and older receiving hip fracture surgery between April 1, 2009, and March 30, 2017, at 80 hospitals in Ontario, Canada. Generalized estimated equations with logistic regression analysis were used to determine the relationship between procedure duration, type of anesthesia, and the occurrence of postoperative delirium. Restricted cubic splines were also generated to visualize this relationship. Data analysis was conducted from July to October 2018, revision in January 2019.

EXPOSURE

Surgery duration, measured as the total time in the operating room.

MAIN OUTCOMES AND MEASURES

A diagnosis of postoperative delirium during hospitalization.

RESULTS

Among 68 131 patients with surgically managed hip fracture (median [interquartile range] age, 84 [78-89] years; 72% women) identified, 7150 patients experienced postoperative delirium. In total, 26 853 patients (39.4%) received general anesthesia. Receiving general anesthesia was associated with a slightly higher rate of postoperative delirium compared with not receiving general anesthesia (2943 [11.0%] vs 4207 [10.2%]; P = .001). The risk for delirium increased with increased surgical duration-every 30-minute increase in the duration of surgery was associated with a 6% increase in the risk for delirium (adjusted odds ratio, 1.06; 95% CI, 1.03-1.08; P < .001). Prolonged surgical duration was associated with a higher incidence of postoperative delirium, and the risk was higher was in patients who had received general anesthesia (adjusted odds ratio, 1.08; 95% CI, 1.04-1.12; P < .001) than in those patients who did not receive GA (adjusted odds ratio, 1.04; 95% CI, 1.01-1.08; P = .01).

CONCLUSIONS AND RELEVANCE

Among older adults receiving hip fracture surgery, both an increased duration of surgery and receiving a general anesthetic were associated with an increased risk for postoperative delirium.

Relationship Between Near-Infrared Spectroscopy-Derived Cerebral Oxygenation and Delirium in Critically Ill Patients: A Systematic Review

BACKGROUND

A common neurological complication of critical illness is delirium, defined as an acute change in level of consciousness, with impaired attention and disorganized thinking. Patients with delirium have increased risk of long-term cognitive dysfunction and mortality. The cause is unknown, which limits our ability to design therapeutic interventions. In patients undergoing surgery, low regional cerebral oxygenation (rSO2), as measured by near-infrared spectroscopy (NIRS), is associated with postoperative neurological dysfunction (eg delirium and long-term cognitive impairment). However, the relationship between NIRS-derived rSO2 and neurological outcomes in critically ill patients is unclear. The objective of this study was to assess the utilization of NIRS-derived rSO2 in critically ill patients outside the operating theater. We aimed to examine the relationship between rSO2 and neurological outcomes as well as to report rSO2 values in this population.

METHODS

The following databases were searched from inception to August 14, 2017: Ovid MedLine, Embase, Cochrane Library, and Web of Science.

RESULTS

Of 1410 articles identified by the search strategy, 8 were ultimately selected for final review. Most (7 of 8) were published since 2014. These studies included a total of 213 patients primarily with shock or respiratory failure. A variety of devices were used to measure rSO2, including INVOS and FORESIGHT. The duration of recording varied from 5 minutes to 72 hours. Four of the 8 studies reported on neurological outcomes. In all 4 studies, rSO2 was lower in critically ill patients who were delirious compared to controls, but this was only statistically significant in 2 of the studies. The heterogeneity in devices and duration of recording precluded meta-analysis.

CONCLUSIONS

There is limited literature describing rSO2 in critically ill patients outside the operating room. Although there may be a slight signal of an association between low rSO2 and delirium, more study is needed to explore this relationship.

The use of cerebral imaging for investigating delirium aetiology

BACKGROUND

This study aims to investigate the frequency and patterns of use of cerebral imaging in delirium and to describe pathological changes associated with delirium using computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

This retrospective observational study included patients with delirium admitted to a tertiary hospital (The Royal Melbourne Hospital, Australia) between January 2015 and August 2016. Data on cerebral imaging was collected and positive imaging findings were defined as: Acute or subacute infarct, haemorrhage, abscess, neoplasm, vasculitis, posterior reversible encephalopathy syndrome, encephalitis, acute demyelination, or fat embolism.

RESULTS

There were 1653 (5% of 32,725) patients with delirium (median age 80 years, inter-quartile range 71-86, 54% male). Thirty-three percent (N = 538) had cerebral imaging (CT only: N = 457, MRI only: N = 10, both: N = 71). In 11% (N = 57) of patients, CT brain scans were positive. MRI brain was completed in 17 patients with a positive CT (17/57), changing the diagnosis in two cases. Fifty-four patients with negative CT scans also had MRI brain; 33% (N = 18) of these were positive. Younger patients were more likely to have MRI compared to CT brain scan. Patients admitted to a neurology unit were more likely to have cerebral imaging.

CONCLUSION

Use of CT brain was common in delirium patients, with an 11% rate of positive findings. Fewer patients had MRI brain scans, which added diagnostic information in some cases. Future studies are needed to define the significance of cerebral imaging in delirium management and establish guidelines for its use.

Validation and Psychometric Properties of the German Version of the Delirium Motor Subtype Scale (DMSS)

Objective: Delirium has been characterized into its subtypes—hypoactive, hyperactive, mixed, or no motor subtype—along with the use of the Delirium Motor Symptom Scale (DMSS). The German version of this scale (DMSS-G), however, has not yet been validated. Method: We determined internal consistency, reliability, and validity of the DMSS-G in the surgical intensive care unit, using DSM-IV-TR criteria and the Delirium Rating Scale–Revised–98. Results: In total, 289 patients were included, and out of these, 122 were delirious. The DMSS-G showed excellent internal consistency (Cronbach’s α = 0.92) and interrater reliability (Fleiss κ = 0.83). Additionally, the overall concurrent validity was substantial (Cramer’s V = 0.69); within subtypes, hyperactive, hypoactive, or mixed, the concurrent validity remained at least substantial (Cohen’s κ = 0.73-0.82) and the sensitivity ranged from 60% to 97%. In contrast, in those with no motor subtype, we found the concurrent validity (Cohen’s κ = 0.31) and sensitivity to be low (22%). Overall, specificity for all individual subtypes was high (82% to 100%). The DMSS was very sensitive in both rating hyperactive and hypoactive motor symptoms of delirium. Conclusion: The DMSS-G is a highly reliable and valid instrument for detecting motor symptoms in delirium, which provides an accurate instrument to classify the motor subtypes of delirium.

2-18F-fluoro-2-deoxyglucose positron emission tomography in delirium

Delirium is a common, serious, yet poorly understood syndrome. Growing evidence suggests cerebral metabolism is fundamentally disturbed; however, it has not been investigated using 2-¹⁸F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in delirium. This prospective study thus explored FDG PET patterns of cerebral glucose metabolism in older inpatients with delirium. A particular emphasis was on the posterior cingulate cortex (PCC), a key region for attention, which is a central feature of delirium. Delirium scans were compared with post-delirium scans using visual analysis and semi-quantitative analysis with NeuroQ; 13 participants (8 female, median 84 y) were scanned during delirium, and 6 scanned again after resolution. On visual analysis, cortical hypometabolism was evident in all participants during delirium (13/13), and improved with delirium resolution (6/6). Using NeuroQ, glucose metabolism was higher post-delirium in the whole brain and bilateral PCC compared to during delirium ( p < 0.05). Greater metabolism in both PCCs correlated with better performance on a neuropsychological test of attention, the WAIS-IV Digit Span Test forwards, and with shorter delirium duration. This research found widespread, reversible cortical hypometabolism during delirium and PCC hypometabolism was associated with inattention during delirium.

Altered cortical brain activity in end stage liver disease assessed by multi-channel near-infrared spectroscopy: Associations with delirium

Delirium is a common and serious psychiatric syndrome caused by an underlying medical condition. It is associated with significant mortality and increased healthcare resource utilization. There are few biological markers of delirium, perhaps related to the etiologic heterogeneity of the syndrome. Functional near-infrared spectroscopy (fNIRS) is an optical topography system to measure changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the cerebral cortex. We examined whether altered cortical brain activity in delirious patients with end stage liver disease (ESLD) is detected by fNIRS. We found that the [oxy-Hb] change during the verbal fluency task (VFT) was reduced in patients with ESLD compared with healthy controls (HC) in the prefrontal and bi-temporal regions. The [oxy-Hb] change during the sustained attention task (SAT) was elevated in patients with ESLD compared to HC in the prefrontal and left temporal regions. Notably, [oxy-Hb] change in the left dorsolateral prefrontal cortex during SAT showed a positive correlation with the severity of delirium. Our results suggest that [oxy-Hb] change in the prefrontal cortex during the sustained attention task measured with fNIRS might serve as a biological marker associated with delirium in ESLD patients.

A Novel Stress-Diathesis Model to Predict Risk of Post-operative Delirium: Implications for Intra-operative Management

Introduction: Risk assessment for post-operative delirium (POD) is poorly developed. Improved metrics could greatly facilitate peri-operative care as costs associated with POD are staggering. In this preliminary study, we develop a novel stress-diathesis model based on comprehensive pre-operative psychiatric and neuropsychological testing, a blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) carbon dioxide (CO₂) stress test, and high fidelity measures of intra-operative parameters that may interact facilitating POD. Methods: The study was approved by the ethics board at the University of Manitoba and registered at clinicaltrials.gov as NCT02126215. Twelve patients were studied. Pre-operative psychiatric symptom measures and neuropsychological testing preceded MRI featuring a BOLD MRI CO₂ stress test whereby BOLD scans were conducted while exposing participants to a rigorously controlled CO₂ stimulus. During surgery the patient had hemodynamics and end-tidal gases downloaded at 0.5 hz. Post-operatively, the presence of POD and POD severity was comprehensively assessed using the Confusion Assessment Measure -Severity (CAM-S) scoring instrument on days 0 (surgery) through post-operative day 5, and patients were followed up at least 1 month post-operatively. Results: Six of 12 patients had no evidence of POD (non-POD). Three patients had POD and 3 had clinically significant confusional states (referred as subthreshold POD; ST-POD) (score ≥ 5/19 on the CAM-S). Average severity for delirium was 1.3 in the non-POD group, 3.2 in ST-POD, and 6.1 in POD (F-statistic = 15.4, p < 0.001). Depressive symptoms, and cognitive measures of semantic fluency and executive functioning/processing speed were significantly associated with POD. Second level analysis revealed an increased inverse BOLD responsiveness to CO₂ pre-operatively in ST-POD and marked increase in the POD groups when compared to the non-POD group. An association was also noted for the patient population to manifest leucoaraiosis as assessed with advanced neuroimaging techniques. Results provide preliminary support for the interacting of diatheses (vulnerabilities) and intra-operative stressors on the POD phenotype. Conclusions: The stress-diathesis model has the potential to aid in risk assessment for POD. Based on these initial findings, we make some recommendations for intra-operative management for patients at risk of POD.

Low brain tissue oxygenation contributes to the development of delirium in critically ill patients: A prospective observational study

PURPOSE

To test the hypothesis that poor brain tissue oxygenation (BtO₂) during the first 24h of critical illness correlates with the proportion of time spent delirious. We also sought to define the physiological determinants of BtO₂.

MATERIALS AND METHODS

Adult patients admitted to the ICU within the previous 24h were considered eligible for enrollment if they required mechanical ventilation, and/or vasopressor support. BtO₂ was measured using near-infrared spectroscopy, for 24h after enrollment. Hourly vital signs and clinically ordered arterial and central venous blood gases were collected throughout BtO₂ monitoring. Patients were screened daily for delirium with the confusion assessment method for the intensive care unit (CAM-ICU).

RESULTS

BtO₂ and the proportion of time spent delirious did not result in a significant correlation (p=0.168). However, critically ill patients who spent the majority of their ICU stay delirious had significantly lower mean BtO₂ compared to non-delirious patients, (p=0.017). BtO₂ correlated positively with central venous pO₂ (p=0.00003) and hemoglobin concentration (p=0.001). Logistic regression indicated that lower BtO₂, higher narcotic doses and a history of alcohol abuse were independent risk factors for delirium.

CONCLUSIONS

Poor cerebral oxygenation during the first 24 hours of critical illness contributes to the development of delirium.

TRIAL REGISTRATION

This trial is registered on clinicaltrials.gov (Identifier: NCT02344043), retrospectively registered January 8, 2015.

Cerebral blood flow MRI in the nondemented elderly is not predictive of post-operative delirium but is correlated with cognitive performance

Three-dimensional Arterial Spin Labeling (ASL) MRI was performed before surgery in a cohort of 146 prospectively enrolled subjects ≥ 70 years old scheduled to undergo elective surgery. We investigated the prospective association between ASL-derived measures of cerebral blood flow (CBF) before surgery with postoperative delirium incidence and severity using whole-brain and globally normalized voxel-wise analysis. We also investigated the cross-sectional association of CBF with patients' baseline performance on specific neuropsychological tests, and with a composite general cognitive performance measure (GCP). Out of 146 subjects, 32 (22%) developed delirium. We found no significant association between global and voxel-wise CBF with delirium incidence or severity. We found the most significant positive associations between CBF of the posterior cingulate and precuneus and the Hopkins Verbal Learning Test - Revised total score, Visual Search and Attention Test (VSAT) score and the GCP composite. VSAT score was also strongly associated with right parietal lobe CBF. ASL can be employed in a large, well-characterized older cohort to examine associations between CBF and age-related cognitive performance. Although ASL CBF measures in regions previously associated with preclinical Alzheimer's Disease were correlated with cognition, they were not found to be indicators of baseline pathology that may increase risk for delirium.

Delirium in critically ill patients

Delirium is common in critically ill patients and associated with increased length of stay in the intensive care unit (ICU) and long-term cognitive impairment. The pathophysiology of delirium has been explained by neuroinflammation, an aberrant stress response, neurotransmitter imbalances, and neuronal network alterations. Delirium develops mostly in vulnerable patients (e.g., elderly and cognitively impaired) in the throes of a critical illness. Delirium is by definition due to an underlying condition and can be identified at ICU admission using prediction models. Treatment of delirium can be improved with frequent monitoring, as early detection and subsequent treatment of the underlying condition can improve outcome. Cautious use or avoidance of benzodiazepines may reduce the likelihood of developing delirium. Nonpharmacologic strategies with early mobilization, reducing causes for sleep deprivation, and reorientation measures may be effective in the prevention of delirium. Antipsychotics are effective in treating hallucinations and agitation, but do not reduce the duration of delirium. Combined pain, agitation, and delirium protocols seem to improve the outcome of critically ill patients and may reduce delirium incidence.

Cerebral Blood Flow Autoregulation in Sepsis for the Intensivist: Why Its Monitoring May Be the Future of Individualized Care

Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.

Absence of association between whole blood viscosity and delirium after cardiac surgery: a case-controlled study

Background

Delirium after cardiothoracic surgery is common and associated with impaired outcomes. Although several mechanisms have been proposed (including changes in cerebral perfusion), the pathophysiology of postoperative delirium remains unclear. Blood viscosity is related to cerebral perfusion and thereby might contribute to the development of delirium after cardiothoracic surgery. The aim of this study was to investigate whether whole blood viscosity differs between cardiothoracic surgery patients with and without delirium.

Methods

In this observational study postoperative whole blood viscosity of patients that developed delirium (cases) were compared with non-delirious cardiothoracic surgery patients (controls). Cases were matched with the controls, yielding a 1:4 case–control study. Serial hematocrit, fibrinogen, and whole blood viscosity were determined pre-operatively and at each postoperative day. Delirium was assessed using the validated Confusion Assessment Method for the Intensive Care Unit or Delirium Screening Observation scale.

Results

In total 80 cardiothoracic surgery patients were screened of whom 12 delirious and 48 matched non-delirious patients were included. No significant difference was found between both groups in fibrinogen (p = 0.36), hematocrit (p = 0.23) and the area under curve of the whole blood viscosity between shear rates 0.02 and 50 s^-1 (p = 0.80) or between shear rates 0.02 and 5 s^-1 (p = 0.78).

Conclusion

In this case control study in cardiothoracic surgery patients changes in whole blood viscosity were not associated with the development of delirium.

Prevalence, determinants, and prognostic significance of delirium in patients with acute heart failure

BACKGROUND

Delirium is a serious syndrome in critically ill patients. However, the prognostic impact of delirium and its determinants in acute heart failure (AHF) patients have not been fully elucidated.

METHODS

We examined 611 AHF patients who were admitted to our institution. Delirium was diagnosed based on the Intensive Care Delirium Screening Checklist (ICDSC).

RESULTS

Delirium developed in 139 patients (23%) during hospitalization. Patients with delirium had higher incidence of non-cardiovascular death (p=0.046) and worsening heart failure (p<0.001) during hospitalization. Among patients who survived at discharge, the incidence of all-cause death, cardiovascular death and non-cardiovascular death after discharge were significantly higher in patients with delirium than those without (log-rank; p<0.001, p=0.001, p<0.001, respectively) during a median follow-up period of 335days. In multivariable model, the development of delirium was an independent determinant of worsening heart failure during hospitalization (OR: 2.44, 95% CI: 1.27-4.63) and all-cause death after discharge (HR: 2.38, 95% CI: 1.30-4.35). Furthermore, multivariate analysis indicated that history of cerebrovascular disease (OR: 2.13, 95% CI: 1.36-3.35), age (OR: 1.43, 95% CI: 1.15-1.80), log BNP (OR: 1.39, 95% CI: 1.09-1.79), serum albumin (OR: 0.84, 95% CI: 0.76-0.93) and blood glucose levels (OR: 1.03, 95% CI: 1.00-1.06) were independent determinants of delirium.

CONCLUSION

In patients with AHF, the development of delirium was associated with poor clinical outcomes, suggesting the importance of early screening and careful monitoring of delirium in such patients.

Serum S100B protein could help to detect cerebral complications associated with extracorporeal membrane oxygenation (ECMO)

BACKGROUND

To investigate if serum S100B protein levels could early detect cerebral complications under treatment extracorporeal membrane oxygenation (ECMO).

METHODS

Serum S100B levels were measured over 5 days in 32 patients with cardiogenic and septic shock, including 15 patients who treated by ECMO and 17 who did not. Cerebral complications included hemorrhage, stroke, encephalopathy with myoclonus, and brain death. Delirium was identified by the positive Confusion Assessment Method in the ICU.

RESULTS

S100B levels were elevated in 24/32 patients (75 %) at ICU admission. Five patients developed cerebral complications (2 hemorrhages with 1 brain death, 1 encephalopathy with myoclonus in the ECMO group and 2 strokes in the non-ECMO group). At day 5, S100B levels were higher in the 5 patients with cerebral complications than in the 27 without cerebral complications, regardless of ECMO (0.426 [0.421, 0.652] vs. 0.102 [0.085, 0.135] μg/L, p = 0.011). S100B levels were also more elevated in 3 patients with than in 12 without cerebral complications associated with ECMO (0.799 [0.325, 0.965] vs. 0.102 [0.09, 0.607] μg/L, p = 0.033). S100B levels were not associated with delirium after sedation withdrawal.

CONCLUSIONS

Measurement serum S100B could be useful to detect cerebral complications in deeply sedated patients associated with ECMO but not for monitoring delirium after sedation withdrawal.

Delirium and dementia with Lewy bodies: distinct diagnoses or part of the same spectrum?

Dementia with Lewy bodies (DLB) is recognised as the second most common form of dementia in older people. Delirium is a condition of acute brain dysfunction for which a pre-existing diagnosis of dementia is a risk factor. Conversely delirium is associated with an increased risk of developing dementia. The reasons for this bidirectional relationship are not well understood. Our aim was to review possible similarities in the clinical presentation and pathophysiology between delirium and DLB, and explore possible links between these diagnoses. A systematic search using Medline, Embase and Psychinfo was performed. References were scanned for relevant articles, supplemented by articles identified from reference lists and those known to the authors. 94 articles were selected for inclusion in the review. Delirium and DLB share a number of clinical similarities, including global impairment of cognition, fluctuations in attention and perceptual abnormalities. Delirium is a frequent presenting feature of DLB. In terms of pathophysiological mechanisms, cholinergic dysfunction and genetics may provide a common link. Neuroimaging studies suggest a brain vulnerability in delirium which may also occur in dementia. The basal ganglia, which play a key role in DLB, have also been implicated in delirium. The role of Cerebrospinal fluid (CSF) and serum biomarkers for both diagnoses is an interesting area although some results are conflicting and further work in this area is needed. Delirium and DLB share a number of features and we hypothesise that delirium may, in some cases, represent early or 'prodromal' DLB. Further research is needed to test the novel hypothesis that delirium may be an early marker for future DLB, which would aid early diagnosis of DLB and identify those at high risk.