Factors Predisposing to Coma and Delirium: Fentanyl and Midazolam Exposure; CYP3A5, ABCB1, and ABCG2 Genetic Polymorphisms; and Inflammatory Factors*

Systemic inflammation and delirium during critical illness

PURPOSE

The purpose of this study was to determine associations between markers of inflammation and endogenous anticoagulant activity with delirium and coma during critical illness.

METHODS

In this prospective cohort study, we enrolled adults with respiratory failure and/or shock treated in medical or surgical intensive care units (ICUs) at 5 centers. Twice per day in the ICU, and daily thereafter, we assessed mental status using the Richmond Agitation Sedation Scale (RASS) and the Confusion Assessment Method-Intensive Care Unit (CAM-ICU). We collected blood samples on study days 1, 3, and 5, measuring levels of C-reactive protein (CRP), interferon gamma (IFN-γ), interleukin (IL)-1 beta (IL-1β), IL-6, IL-8, IL-10, IL-12, matrix metalloproteinase-9 (MMP-9), tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1), and protein C using validated protocols. We used multinomial logistic regression to analyze associations between biomarkers and the odds of delirium or coma versus normal mental status the following day, adjusting for age, sepsis, Sequential Organ Failure Assessment (SOFA), study day, corticosteroids, and sedatives.

RESULTS

Among 991 participants with a median age (interquartile range, IQR) of 62 [53-72] years and enrollment SOFA of 9 [7-11], higher concentrations of IL-6 (odds ratio [OR] [95% CI]: 1.8 [1.4-2.3]), IL-8 (1.3 [1.1-1.5]), IL-10 (1.5 [1.2-1.8]), TNF-α (1.2 [1.0-1.4]), and TNFR1 (1.3 [1.1-1.6]) and lower concentrations of protein C (0.7 [0.6-0.8])) were associated with delirium the following day. Higher concentrations of CRP (1.4 [1.1-1.7]), IFN-γ (1.3 [1.1-1.5]), IL-6 (2.3 [1.8-3.0]), IL-8 (1.8 [1.4-2.3]), and IL-10 (1.5 [1.2-2.0]) and lower concentrations of protein C (0.6 [0.5-0.8]) were associated with coma the following day. IL-1β, IL-12, and MMP-9 were not associated with mental status.

CONCLUSION

Markers of inflammation and possibly endogenous anticoagulant activity are associated with delirium and coma during critical illness.

A comparation of dexmedetomidine and midazolam for sedation in patients with mechanical ventilation in ICU: A systematic review and meta-analysis

BACKGROUND

The use of dexmedetomidine rather than midazolam may improve ICU outcomes. We summarized the available recent evidence to further verify this conclusion.

METHODS

An electronic search of PubMed, Medline, Embase, Cochrane Library, and Web of Science was conducted. Risk ratios (RR) were used for binary categorical variables, and for continuous variables, weighted mean differences (WMD) were calculated, the effect sizes are expressed as 95% confidence intervals (CI), and trial sequential analysis was performed.

RESULTS

16 randomized controlled trials were enrolled 2035 patients in the study. Dexmedetomidine as opposed to midazolam achieved a shorter length of stay in ICU (MD = -2.25, 95%CI = -2.94, -1.57, p<0.0001), lower risk of delirium (RR = 0.63, 95%CI = 0.50, 0.81, p = 0.0002), and shorter duration of mechanical ventilation (MD = -0.83, 95%CI = -1.24, -0.43, p<0.0001). The association between dexmedetomidine and bradycardia was also found to be significant (RR 2.21, 95%CI 1.31, 3.73, p = 0.003). We found no difference in hypotension (RR = 1.44, 95%CI = 0.87, 2.38, P = 0.16), mortality (RR = 1.02, 95%CI = 0.83, 1.25, P = 0.87), neither in terms of adverse effects requiring intervention, hospital length of stay, or sedation effects.

CONCLUSIONS

Combined with recent evidence, compared with midazolam, dexmedetomidine decreased the risk of delirium, mechanical ventilation, length of stay in the ICU, as well as reduced patient costs. But dexmedetomidine could not reduce mortality and increased the risk of bradycardia.

Blood-brain barrier dysfunction in intensive care unit

The central nervous system is characterized by a peculiar vascularization termed blood-brain barrier (BBB), which regulates the exchange of cells and molecules between the cerebral tissue and the whole body. BBB dysfunction is a life-threatening condition since its presence corresponds to a marker of severity in most diseases encountered in the intensive care unit (ICU). During critical illness, inflammatory response, cytokine release, and other phenomena activating the brain endothelium contribute to alterations in the BBB and increase its permeability to solutes, cells, nutrients, and xenobiotics. Moreover, patients in the ICU are often old, with underlying acute or chronic diseases, and overly medicated due to their critical condition; these factors could also contribute to the development of BBB dysfunction. An accurate diagnostic approach is critical for the identification of the mechanisms underlying BBB alterations, which should be rapidly managed by intensivists. Several methods were developed to investigate the BBB and assess its permeability. Nevertheless, in humans, exploration of the BBB requires the use of indirect methods. Imaging and biochemical methods can be used to study the abnormal passage of molecules through the BBB. In this review, we describe the structural and functional characteristics of the BBB, present tools and methods for probing this interface, and provide examples of the main diseases managed in the ICU that are related to BBB dysfunction.

Association Between Sedative Medication Administration and Delirium Development in a Medical Intensive Care Unit

Background: Delirium develops frequently in intensive care unit (ICU) patients. Societal guidelines have suggested that benzodiazepines may cause delirium. This study investigates if a change in sedation administration use over time is associated with changes in delirium incidence. Methods: This was a retrospective cohort study conducted over a 4 year time period in a medical ICU. All data was abstracted from a local data warehouse. The primary outcome of the study was the association between annual cumulative benzodiazepine use and incidence of delirium during the study period. Data was analyzed using descriptive characteristics and Spearman's correlation coefficient. Additionally, multivariate logistic regression was performed to identify independent risk factors for delirium development. Results: From 2015 to 2018, annual total benzodiazepine administration decreased from 62,215 mg to 18,105 mg lorazepam equivalents (p = <.01). The cumulative dose of dexmedetomidine increased, with 657,262 mcg administered in 2015 and 1,476,951 mcg in 2018 (p < .01). No differences in annual delirium incidence were found. Risk factors that were significantly correlated with delirium following multivariate logistic regression included acute respiratory distress syndrome, renal failure, hepatic failure, septic shock, severe alcohol withdrawal, vasopressor use, corticosteroid use, benzodiazepine use, antipsychotic use, opiate use, and propofol use. Conclusions: A profound change in sedation medication paradigm did not influence delirium rates in a medical ICU.

Recent advances in the in vitro and in vivo methods to assess impact of P-glycoprotein and breast cancer resistance protein transporters in central nervous system drug disposition

One challenge in central nervous system (CNS) drug discovery has been ensuring the blood-brain barrier (BBB) penetration of compounds at an efficacious concentration that provides suitable safety margins for clinical investigation. Research providing for the accurate prediction of brain penetration of compounds during preclinical discovery is important to a CNS program. In the BBB, P-glycoprotein (P-gp) (ABCB1) and breast cancer resistance protein (BCRP) (ABCG2) transporters have been demonstrated to play a major role in the active efflux of endogenous compounds and xenobiotics out of the brain microvessel cells and back to the systemic circulation. In the past 10 years, there has been significant technological improvement in the sensitivity of quantitative proteomics methods, in vivo imaging, in vitro methods of organoid and microphysiological systems, as well as in silico quantitative physiological based pharmacokinetic and systems pharmacology models. Scientists continually leverage these advancements to interrogate the distribution of compounds in the CNS which may also show signals of substrate specificity of P-gp and/or BCRP. These methods have shown promise toward predicting and quantifying the unbound concentration(s) within the brain relevant for efficacy or safety. In this review, the authors have summarized the in vivo, in vitro, and proteomics advancements toward understanding the contribution of P-gp and/or BCRP in restricting the entry of compounds to the CNS of either healthy or special populations. Special emphasis has been provided on recent investigations on the application of a proteomics-informed approach to predict steady-state drug concentrations in the brain. Moreover, future perspectives regarding the role of these transporters in newer modalities are discussed.

Increased postoperative myeloperoxidase concentration associated with low baseline antioxidant capacity as the risk factor of delirium after cardiac surgery

BACKGROUND

Though risk factors of postoperative delirium are well described, its pathophysiology is still undiscovered. The primary objective of the current study is to assess whether increased pre- and postoperative myeloperoxidase (MPO) levels are associated with postoperative delirium in the population of cardiac surgery patients. The secondary objective is to evaluate the correlation between MPO levels and serum antioxidant capacity (AC).

METHODS

The patients' cognitive status was assessed one day preoperatively with the use of the Mini-Mental State Examination Test and the Clock Drawing Test. A diagnosis of major depressive disorder and anxiety disorders was established based on DSM-5 criteria. Blood samples for MPO and AC levels were collected both pre- and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used to screen for a diagnosis of delirium.

RESULTS

Delirium occurred in 34% (61 of 177) of patients. Multivariable logistic regression analysis revealed that increased postoperative MPO concentration was independently associated with postoperative delirium development, and negatively correlated with lower baseline serum AC.

CONCLUSIONS

Cardiac surgery patients with less efficient antioxidative mechanisms experience a higher postoperative peak of serum MPO, which in turn may predispose to postoperative delirium development.KEY MESSAGESMPO is a lysosomal enzyme with strong pro-oxidative and pro-inflammatory properties.Cardiac surgery patients who have increased concentration of postoperative MPO are at significantly higher risk of postoperative delirium development.This higher level of postoperative MPO is negatively correlated with baseline antioxidant capacity (AC).It can be hypothesized that individuals with decreased baseline AC experience a higher peak of MPO post-surgery due to less efficient antioxidative mechanisms, which in turn contributes to postoperative delirium development.

Efficacy and Safety of Remimazolam Besylate versus Dexmedetomidine for Sedation in Non-Intubated Older Patients with Agitated Delirium After Orthopedic Surgery: A Randomized Controlled Trial

Purpose

The purpose of the present study was to investigate the efficacy and safety of remimazolam besylate compared with dexmedetomidine for the relief of agitated delirium in non-intubated older patients after orthopedic surgery.

Patients and methods

Seventy-five patients were randomly divided into two groups. Patients assigned to the remimazolam group received a loading dose of 0.075 mg/kg remimazolam besylate over 1 minute, followed by a continuous infusion of 0.1 to 0.3 mg/kg/h. Subjects randomized to the dexmedetomidine group received a loading infusion of 0.5 μg/kg dexmedetomidine over 10 minutes, followed by a maintenance dose of 0.2 to 0.7 μg/kg/h. Meanwhile, RASS score-guided dose titration was followed. To assess the efficacy of the study drugs in terms of time to resolution of agitation, time to first achievement of target sedation, percentage of time within the target sedation range, and time to delirium resolution. Safety of the sedatives was evaluated by adverse events during hospitalization.

Results

Time to resolution of agitation did not differ between the two groups. The time to first achievement of target sedation was 19.0 (9.5 to 31.0) minutes for remimazolam besylate vs 43.5 (15.0 to 142.5) minutes for dexmedetomidine (P < 0.001). Percentage of time within the target sedation range was 77.8% for remimazolam besylate-treated patients and 67.4% for dexmedetomidine-treated patients (P = 0.001). Patients in the remimazolam group had longer time to delirium resolution (29.5 [21.3 to 32.5] hours) than those in the dexmedetomidine group (22.8 [18.9 to 28.5] hours) (P = 0.042). Patients sedated with remimazolam besylate had more oversedation (P = 0.036) but less hypotension (P = 0.007).

Conclusion

Compared with dexmedetomidine, remimazolam besylate was equally effective in relieving agitation, and resulted in earlier achievement of sedation goal and more controllable sedation. Remimazolam may be an ideal agent for obtaining rapid tranquillisation.

Transfusion-Associated Delirium in Children: No Difference Between Short Storage Versus Standard Issue RBCs

OBJECTIVES

Primary objective is to determine if transfusion of short storage RBCs compared with standard issue RBCs reduced risk of delirium/coma in critically ill children. Secondary objective is to assess if RBC transfusion was independently associated with delirium/coma.

DESIGN

This study was performed in two stages. First, we compared patients receiving either short storage or standard RBCs in a multi-institutional prospective randomized controlled trial. Then, we compared all transfused patients in the randomized controlled trial with a single-center cohort of nontransfused patients matched for confounders of delirium/coma.

SETTING

Twenty academic PICUs who participated in the Age of Transfused Blood in Critically Ill Children trial.

PATIENTS

Children 3 days to 16 years old who were transfused RBCs within the first 7 days of admission.

INTERVENTIONS

Subjects were randomized to either short storage RBC study arm (defined as RBCs stored for up to seven days) or standard issue RBC study arm. In addition, subjects were screened for delirium prior to transfusion and every 12 hours after transfusion for up to 3 days.

MEASUREMENTS AND MAIN RESULTS

Primary outcome measure was development of delirium/coma within 3 days of initial transfusion. Additional outcome measures were dose-response relationship between volume of RBCs transfused and delirium/coma, and comparison of delirium/coma rates between transfused patients and individually matched nontransfused patients. We included 146 subjects in the stage I analysis; 69 were randomized to short storage RBCs and 77 to standard issue. There was no significant difference in delirium/coma development between study arms (79.5% vs 70.1%; p = 0.184). In the stage II analysis, adjusted odds for delirium in the transfused cohort was more than eight-fold higher than in the nontransfused matched cohort, even after controlling for hemoglobin (adjusted odds ratio, 8.9; CI, 2.8-28.4; p < 0.001).

CONCLUSIONS

RBC transfusions (and not anemia) are independently associated with increased odds of subsequent delirium/coma. However, storage age of RBCs does not affect delirium risk.

Toxic-metabolic encephalopathy in adults: Critical discussion and pragmatical diagnostic approach

Toxic-metabolic encephalopathy (TME) results from an acute cerebral dysfunction due to different metabolic disturbances including medications or illicit-drugs. It can lead to altered consciousness, going from delirium to coma, which may require intensive care and invasive mechanical ventilation. Even if it is a life-threatening condition, TME might have an excellent prognosis if its etiology is rapidly identified and treated adequately. This review summarizes the main etiologies, their differential diagnosis, and diagnostic strategy and management of TME with a critical discussion on the definition of TME.

Opioid Use Increases the Risk of Delirium in Critically Ill Adults Independently of Pain

Rationale: It is unclear whether opioid use increases the risk of ICU delirium. Prior studies have not accounted for confounding, including daily severity of illness, pain, and competing events that may preclude delirium detection.Objectives: To evaluate the association between ICU opioid exposure, opioid dose, and delirium occurrence.Methods: In consecutive adults admitted for more than 24 hours to the ICU, daily mental status was classified as awake without delirium, delirium, or unarousable. A first-order Markov model with multinomial logistic regression analysis considered four possible next-day outcomes (i.e., awake without delirium, delirium, unarousable, and ICU discharge or death) and 11 delirium-related covariables (baseline: admission type, age, sex, Acute Physiology and Chronic Health Evaluation IV score, and Charlson comorbidity score; daily: ICU day, modified Sequential Organ Failure Assessment, ventilation use, benzodiazepine use, and severe pain). This model was used to quantify the association between opioid use, opioid dose, and delirium occurrence the next day.Measurements and Main Results: The 4,075 adults had 26,250 ICU days; an opioid was administered on 57.0% (n = 14,975), severe pain occurred on 7.0% (n = 1,829), and delirium occurred on 23.5% (n = 6,176). Severe pain was inversely associated with a transition to delirium (odds ratio [OR] 0.72; 95% confidence interval [CI], 0.53-0.97). Any opioid administration in awake patients without delirium was associated with an increased risk for delirium the next day [OR, 1.45; 95% CI, 1.24-1.69]. Each daily 10-mg intravenous morphine-equivalent dose was associated with a 2.4% increased risk for delirium the next day.Conclusions: The receipt of an opioid in the ICU increases the odds of transitioning to delirium in a dose-dependent fashion.

The complex interaction of genetics and delirium: a systematic review and meta-analysis

The objective is to understand genetic predisposition to delirium. Following PRISMA guidelines, we undertook a systematic review of studies involving delirium and genetics in the databases of Pubmed, Scopus, Cochrane Library and PsycINFO, and performed a meta-analysis when appropriate. We evaluated 111 articles, of which 25 were finally included in the analysis. The studies were assessed by two independent researchers for methodological quality using the Downs and Black Tool and for genetic analysis quality. We performed a meta-analysis of 10 studies of the Apolipoprotein E (APOE) gene, obtaining no association with the presence of delirium (LOR 0.18, 95% CI - 0.10-0.47, p = 0.21). Notably, only 5 out of 25 articles met established criteria for genetic studies (good quality) and 6 were of moderate quality. Seven studies found an association with APOE4, the dopamine transporter gene SCL6A3, dopamine receptor 2 gene, glucocorticoid receptor, melatonin receptor and mitochondrial DNA haplotypes. One genome-wide association study found two suggestive long intergenic non-coding RNA genes. Five studies found no association with catechol-o-methyltransferase, melatonin receptor or several interleukins genes. The studies were heterogenous in establishing the presence of delirium. Future studies with large samples should further specify the delirium phenotype and deepen our understanding of interactions between genes and other biological factors.

The central nervous system during lung injury and mechanical ventilation: a narrative review

Mechanical ventilation induces a number of systemic responses for which the brain plays an essential role. During the last decade, substantial evidence has emerged showing that the brain modifies pulmonary responses to physical and biological stimuli by various mechanisms, including the modulation of neuroinflammatory reflexes and the onset of abnormal breathing patterns. Afferent signals and circulating factors from injured peripheral tissues, including the lung, can induce neuronal reprogramming, potentially contributing to neurocognitive dysfunction and psychological alterations seen in critically ill patients. These impairments are ubiquitous in the presence of positive pressure ventilation. This narrative review summarises current evidence of lung-brain crosstalk in patients receiving mechanical ventilation and describes the clinical implications of this crosstalk. Further, it proposes directions for future research ranging from identifying mechanisms of multiorgan failure to mitigating long-term sequelae after critical illness.

Meta-analysis of ICU Delirium Biomarkers and Their Alignment With the NIA-AA Research Framework

BACKGROUND

Between 30% and 80% of survivors of critical illness experience cognitive impairment, but the underlying mechanisms remain unknown.

OBJECTIVE

To determine whether intensive care unit (ICU) delirium biomarkers align with the National Institute on Aging-Alzheimer's Association (NIA-AA) research framework for diagnostic biomarkers for Alzheimer disease and other related dementias (ADRD).

METHODS

Ovid MEDLINE, PsycInfo, Embase, and the Cochrane Library were systematically searched for articles published between January 1, 2000, and February 20, 2020, on the relationship between delirium and biomarkers listed in the NIA-AA framework. Only studies that addressed delirium in the ICU setting and fluid biomarkers were included in these analyses.

RESULTS

Of 61 256 records screened, 38 studies met inclusion criteria, 8 of which were suitable for meta-analysis. In pooled analysis, significant associations were found between ICU delirium and amyloid β-peptide 1-40 (standard mean difference [SMD], 0.42; 95% CI, 0.09-0.75), interleukin (IL)-1 receptor antagonist (SMD, 0.58; 95% CI, 0.21-0.94), and IL-6 (SMD, 0.31; 95% CI, 0.06-0.56). No significant association was observed in pooled analyses between ICU delirium and the other biomarkers. Few studies have examined ICU delirium and pathologic tau or neurodegeneration biomarkers.

CONCLUSIONS

Inflammatory biomarkers and amyloid β are associated with ICU delirium and point to potential overlapping mechanisms between delirium and ADRD. Critical care providers should consider integrating diagnostic approaches used in ADRD in their assessment of post-ICU cognitive dysfunction.

Disease-Induced Modulation of Drug Transporters at the Blood-Brain Barrier Level

The blood–brain barrier (BBB) is a highly selective and restrictive semipermeable network of cells and blood vessel constituents. All components of the neurovascular unit give to the BBB its crucial and protective function, i.e., to regulate homeostasis in the central nervous system (CNS) by removing substances from the endothelial compartment and supplying the brain with nutrients and other endogenous compounds. Many transporters have been identified that play a role in maintaining BBB integrity and homeostasis. As such, the restrictive nature of the BBB provides an obstacle for drug delivery to the CNS. Nevertheless, according to their physicochemical or pharmacological properties, drugs may reach the CNS by passive diffusion or be subjected to putative influx and/or efflux through BBB membrane transporters, allowing or limiting their distribution to the CNS. Drug transporters functionally expressed on various compartments of the BBB involve numerous proteins from either the ATP-binding cassette (ABC) or the solute carrier (SLC) superfamilies. Pathophysiological stressors, age, and age-associated disorders may alter the expression level and functionality of transporter protein elements that modulate drug distribution and accumulation into the brain, namely, drug efficacy and toxicity. This review focuses and sheds light on the influence of inflammatory conditions and diseases such as Alzheimer’s disease, epilepsy, and stroke on the expression and functionality of the BBB drug transporters, the consequential modulation of drug distribution to the brain, and their impact on drug efficacy and toxicity.

Emerging benefits and drawbacks of α2 -adrenoceptor agonists in the management of sepsis and critical illness

Agonists of α₂ -adrenoceptors are increasingly being used for the provision of comfort, sedation and the management of delirium in critically ill patients, with and without sepsis. In this context, increased sympathetic and inflammatory activity are common pathophysiological features linked to multi-organ dysfunction, particularly in patients with sepsis or those undergoing cardiac surgery requiring cardiopulmonary bypass. Experimental and clinical studies support the notion that the α₂ -adrenoceptor agonists, dexmedetomidine and clonidine, mitigate sympathetic and inflammatory overactivity in sepsis and cardiac surgery requiring cardiopulmonary bypass. These effects can protect vital organs, including the cardiovascular system, kidneys, heart and brain. We review the pharmacodynamic mechanisms by which α₂ -adrenoceptor agonists might mitigate multi-organ dysfunction arising from pathophysiological conditions associated with excessive inflammatory and adrenergic stress in experimental studies. We also outline recent clinical trials that have examined the use of dexmedetomidine in critically ill patients with and without sepsis and in patients undergoing cardiac surgery.

Clinical Pharmacists: An Invaluable Part of the Coronavirus Disease 2019 Frontline Response

Although coronavirus disease 2019 was first identified in December 2019, it rapidly spread and became a global pandemic. The number of patients infected with the novel coronavirus (severe acute respiratory syndrome coronavirus 2) rose rapidly in New York State, placing great stress on healthcare systems. The traditional roles and practices of healthcare providers were dramatically redefined to meet the demand to care for the large number of ill patients. While literature reports on the experiences of many frontline staff, there is a scarcity of reports on the role of clinical pharmacists during this crisis. We report the role of critical care clinical pharmacists at a large academic medical center in New York City during this pandemic. Effective crisis management required clinical pharmacists to employ a wide array of skills and knowledge. Areas included clinical expertise, education, data analysis, health informatics infrastructure, and inventory management in times of surging medication use and manufacturer shortages. Clinical pharmacists fulfilled an essential service during the coronavirus pandemic by working to ensure the best possible outcomes for the patients they served on the frontline.

Pain management protocol implementation and opioid consumption in critical care: an interrupted time series analysis

OBJECTIVE

To evaluate the impact of an opioid-sparing pain management protocol on overall opioid consumption and clinical outcomes.

METHODS

This was a single-center, quasi-experimental, retrospective, before and after cohort study. We used an interrupted time series to analyze changes in the levels and trends of the utilization of different analgesics. We used bivariate comparisons in the before and after cohorts as well as logistic regression and quantile regression for adjusted estimates.

RESULTS

We included 988 patients in the preintervention period and 1,838 in the postintervention period. Fentanyl consumption was slightly increasing before the intervention (β = 16; 95%CI 7 - 25; p = 0.002) but substantially decreased in level with the intervention (β = - 128; 95%CI -195 - -62; p = 0.001) and then progressively decreased (β = - 24; 95%CI -35 - -13; p < 0.001). There was an increasing trend in the utilization of dipyrone. The mechanical ventilation duration was significantly lower (median difference: - 1 day; 95%CI -1 - 0; p < 0.001), especially for patients who were mechanically ventilated for a longer time (50th percentile difference: -0.78; 95%CI -1.51 - -0.05; p = 0.036; 75th percentile difference: -2.23; 95%CI -3.47 - -0.98; p < 0.001).

CONCLUSION

A pain management protocol could reduce the intensive care unit consumption of fentanyl. This strategy was associated with a shorter mechanical ventilation duration.

A systematic review of the overlap of fluid biomarkers in delirium and advanced cancer-related syndromes

BACKGROUND

Delirium is a serious and distressing neurocognitive disorder of physiological aetiology that is common in advanced cancer. Understanding of delirium pathophysiology is largely hypothetical, with some evidence for involvement of inflammatory systems, neurotransmitter alterations and glucose metabolism. To date, there has been limited empirical consideration of the distinction between delirium pathophysiology and that of the underlying disease, for example, cancer where these mechanisms are also common in advanced cancer syndromes such as pain and fatigue. This systematic review explores biomarker overlap in delirium, specific advanced cancer-related syndromes and prediction of cancer prognosis.

METHODS

A systematic review (PROSPERO CRD42017068662) was conducted, using MEDLINE, PubMed, Embase, CINAHL, CENTRAL and Web of Science, to identify body fluid biomarkers in delirium, cancer prognosis and advanced cancer-related syndromes of interest. Studies were excluded if they reported delirium tremens only; did not measure delirium using a validated tool; the sample had less than 75% of participants with advanced cancer; measured tissue, genetic or animal biomarkers, or were conducted post-mortem. Articles were screened for inclusion independently by two authors, and data extraction and an in-depth quality assessment conducted by one author, and checked by two others.

RESULTS

The 151 included studies were conducted in diverse settings in 32 countries between 1985 and 2017, involving 28130 participants with a mean age of 69.3 years. Seventy-one studies investigated delirium biomarkers, and 80 studies investigated biomarkers of an advanced cancer-related syndrome or cancer prognosis. Overall, 41 biomarkers were studied in relation to both delirium and either an advanced cancer-related syndrome or prognosis; and of these, 24 biomarkers were positively associated with either delirium or advanced cancer syndromes/prognosis in at least one study. The quality assessment showed large inconsistency in reporting.

CONCLUSION

There is considerable overlap in the biomarkers in delirium and advanced cancer-related syndromes. Improving the design of delirium biomarker studies and considering appropriate comparator/controls will help to better understanding the discrete pathophysiology of delirium in the context of co-existing illness.

Association of neuronal repair biomarkers with delirium among survivors of critical illness

PURPOSE

Delirium is prevalent but with unclear pathogenesis. Neuronal injury repair pathways may be protective. We hypothesized that higher concentrations of neuronal repair biomarkers would be associated with decreased delirium in critically ill patients.

MATERIALS AND METHODS

We performed a nested study of hospital survivors within a prospective cohort that enrolled patients within 72 h of respiratory failure or shock. We measured plasma concentrations of ubiquitin carboxyl-terminal-esterase-L1 (UCHL1) and brain-derived neurotrophic factor (BDNF) from blood collected at enrollment. Delirium was assessed twice daily using the CAM-ICU. Multivariable regression was used to examine the associations between biomarkers and delirium prevalence/duration, adjusting for covariates and interactions with age and IL-6 plasma concentration.

RESULTS

We included 427 patients with a median age of 59 years (IQR 48-69) and APACHE II score of 25 (IQR 19-30). Higher plasma concentration of UCHL1 on admission was independently associated with lower prevalence of delirium (p = .04) but not associated with duration of delirium (p = .06). BDNF plasma concentration was not associated with prevalence (p = .26) or duration of delirium (p = .36).

CONCLUSIONS

During critical illness, higher UCHL1 plasma concentration is associated with lower prevalence of delirium; BDNF plasma concentration is not associated with delirium. Clinical trial number: NCT00392795; https://clinicaltrials.gov/ct2/show/NCT00392795.

Benzodiazepines and Development of Delirium in Critically Ill Children: Estimating the Causal Effect

OBJECTIVES

Benzodiazepine use may be associated with delirium in critically ill children. However, benzodiazepines remain the first-line sedative choice in PICUs. Objectives were to determine the temporal relationship between administration of benzodiazepines and delirium development, control for time-varying covariates such as mechanical ventilation and opiates, and evaluate the association between dosage of benzodiazepines and subsequent delirium.

DESIGN

Retrospective observational study.

SETTING

Academic tertiary care PICU.

PATIENTS

All consecutive admissions from January 2015 to June 2015.

INTERVENTIONS

Retrospective assessment of benzodiazepine exposure in a population that had been prospectively screened for delirium.

MEASUREMENTS AND MAIN RESULTS

All subjects were prospectively screened for delirium throughout their stay, using the Cornell Assessment for Pediatric Delirium, with daily cognitive status assigned as follows: delirium, coma, or normal. Multivariable mixed effects modeling determined predictors of delirium overall, followed by subgroup analysis to assess effect of benzodiazepines on subsequent development of delirium. Marginal structural modeling was used to create a pseudorandomized sample and control for time-dependent variables, obtaining an unbiased estimate of the relationship between benzodiazepines and next day delirium. The cumulative daily dosage of benzodiazepines was calculated to test for a dose-response relationship. Benzodiazepines were strongly associated with transition from normal cognitive status to delirium, more than quadrupling delirium rates (odds ratio, 4.4; CI, 1.7-11.1; p < 0.002). Marginal structural modeling demonstrated odds ratio 3.3 (CI, 1.4-7.8), after controlling for time-dependent confounding of cognitive status, mechanical ventilation, and opiates. With every one log increase in benzodiazepine dosage administered, there was a 43% increase in risk for delirium development.

CONCLUSIONS

Benzodiazepines are an independent and modifiable risk factor for development of delirium in critically ill children, even after carefully controlling for time-dependent covariates, with a dose-response effect. This temporal relationship suggests causality between benzodiazepine exposure and pediatric delirium and supports limiting the use of benzodiazepines in critically ill children.

[Metabolic encephalopathies]

Metabolic encephalopathies (ME) are a common cause of admission to emergency rooms, to hospitalization wards or to intensive care units. They could account for 10 to 20% of causes of comatose states in ICU and could be associated to a poor outcome especially in older patients. Nevertheless, they are often reversible and are associated with a favorable outcome when diagnosed and rapidly treated. They correspond to an altered brain functioning secondary to the deficiency of a substance that is mandatory for the normal brain functioning or to the accumulation of a substance that can be either endogenous or exogenous. It preferably occurs in co-morbid patients, complicating its diagnosis and its management. Altered brain functioning, going from mild neuropsychological impairment to coma, movement disorders especially myoclonus and the absence of any obvious differential diagnosis are highly suggestive of the diagnosis. Whereas some biological samplings and brain MRI are essential to rule out differential diagnosis, some others, such as electroencephalogram, may be able to propose important clues in favor of the diagnosis. Once simple symptomatic measures are introduced, the treatment consists mainly in the correction of the cause. Specific treatment options are only seldom available for ME; this is the case for hepatic encephalopathy and some drug-induced encephalopathies. We will successively describe in this review the main pathophysiological mechanisms, the main causes, favoring circumstances of ME, the differential diagnosis to rule out and the etiological work-up for the diagnosis. Finally, a diagnostic and therapeutic strategy for the care of patients with ME will be proposed.

Effects of OPRM1 and ABCB1 gene polymorphisms on the analgesic effect and dose of sufentanil after thoracoscopic-assisted radical resection of lung cancer

OBJECTIVE

To study the effects of single-nucleotide polymorphisms of the OPRM1 and ABCB1 genes on the analgesic effect and consumption of sufentanil after thoracoscopic-assisted radical resection of lung cancer.

METHODS

A total of 225 Chinese Han nationality patients undergoing thoracoscopic-assisted radical resection of lung cancer were enrolled in the present study. Among them, 132 were males (58.67%) and 93 (41.33%) were females having American Society of Anesthesiologists statuses classified as grades I or II. The rs1799971, rs563649 and rs1323040 genotypes of the OPRM1 gene and rs2032582, rs1045642 and rs1128503 genotypes of the ABCB1 gene were detected by Sanger sequencing. The state anxiety index and pressure pain threshold were assessed preoperatively. Sufentanil was administered intravenously to maintain anesthesia. The doses and side effects of sufentanil consumed 6 h (T1), 24 h (T2) and 48 h (T3) after surgery were recorded.

RESULTS

The sufentanil doses at T1, T2 and T3 were significantly higher in radical-operation lung cancer patients with mutant homozygous rs1799971 and rs1323040 loci in the OPRM1 gene and rs2032582 and rs1128503 loci in the ABCB1 gene. The doses of sufentanil consumed by mutant heterozygous lung cancer patients at T1, T2 and T3 were significantly higher than those consumed by patients without mutations, and the differences were statistically significant (P<0.05). There was no significant difference in sufentanil doses consumed by lung cancer patients with mutant homozygous, mutant heterozygous and wild-type rs563649 locus of the OPRM1 gene and rs1045642 locus of the ABCB1 gene at T1, T2 and T3 (P>0.05). There was no significant difference in the visual analog scale scores at T1, T2 and T3 for different genotypes of OPRM1 and ABCB1 genes in lung cancer patients (P>0.05). No significant difference was found between the adverse reactions of OPRM1 and ABCB1 genotypes in patients undergoing radical resection of lung cancer (P>0.05).

CONCLUSION

The rs1799971 and rs1323040 polymorphisms of the OPRM1 gene and rs2032582 and rs1128503 polymorphisms of the ABCB1 gene are related to the analgesic effect and consumed dose of sufentanil in Chinese Han patients undergoing radical operation of lung cancer.

Pharmacogenomics in Critical Care

Since the successful completion of the Human Genome Project in 2003, extensive genomic research has continued to alter pathophysiology at the molecular level. This research includes investigation of the specific receptors and metabolizing enzymes in drug pharmacodynamics and pharmacokinetics, specifically the cytochrome P450 system located primarily in the liver. In this article, pharmacogenomics and the role of the cytochrome P450 system in metabolism of various drugs are discussed. Specifically, drugs that are used in the critical care setting and are of clinical significance to the bedside critical care nurse are examined.

Comparison of clinical practice guidelines for the management of pain, agitation, and delirium in critically ill adult patients

Guideline‐based management approaches for pain, agitation, and delirium (PAD) in critically ill adult patients are widely believed to result in good outcomes. However, there are some differences in the recommendations and evidence levels among the management guidelines established for PAD. To identify and compare the current management guidelines, we used the PubMed database. The PAD guidelines and Federación Panamericana e Ibérica de Sociedades de Medicina Crítica y Terapia Intensiva (FEPIMCTI) guidelines were identified from our search. We compared the main aspects of these two guidelines as well as the Japanese guidelines for the management of PAD (J‐PAD guidelines). The PAD, FEPIMCTI, and J‐PAD guidelines contained a total of 4, 12, and 5 sections, having 32, 138, and 37 recommendations, respectively, pertaining to routine monitoring of pain in adult patients in the intensive care unit. Intravenous opioids were recommended as the first‐line drug of choice for treating pain. Sedative titrated to maintain a light, rather than deep, level of sedation can be given unless clinically contraindicated. Although neither the PAD nor J‐PAD guidelines recommend use of a pharmacologic delirium prevention protocol or treatment with any pharmacological agent to reduce the duration of delirium, the FEPIMCTI guidelines provide such recommendations. The FEPIMCTI guidelines provide suggestions on which analgesics to use for several different cases and present algorithms for sedation and analgesia. The outlines of the three guidelines are similar, and all reinforce the management of PAD to improve patient outcomes.

Sedative Plasma Concentrations and Delirium Risk in Critical Illness

BACKGROUND

The relationship between plasma concentration of sedatives and delirium is unknown.

OBJECTIVE

We hypothesized that higher plasma concentrations of lorazepam are associated with increased delirium risk, whereas higher plasma concentrations of dexmedetomidine are associated with reduced delirium risk.

METHODS

This prospective cohort study was embedded in a double-blind randomized clinical trial, where ventilated patients received infusions of lorazepam and dexmedetomidine. Plasma concentrations of these drugs and delirium assessments were measured at least daily. A multivariable logistic regression model accounting for repeated measures was used to analyze associations between same-day plasma concentrations of lorazepam and dexmedetomidine (exposures) and the likelihood of next-day delirium (outcome), adjusting for same-day mental status (delirium, coma, or normal) and same-day fentanyl doses.

RESULTS

This critically ill cohort (n = 103) had a median age of 60 years (IQR: 48-66) with APACHE II score of 28 (interquartile range [IQR] = 24-32), where randomization resulted in assignment to lorazepam (n = 51) or dexmedetomidine (n = 52). After adjusting for same-day fentanyl dose and mental status, higher plasma concentrations of lorazepam were associated with increased probability of next-day delirium (comparing 500 vs 0 ng/mL; odds ratio [OR] = 13.2; 95% CI = 1.4-120.1; P = 0.02). Plasma concentrations of dexmedetomidine were not associated with next-day delirium (comparing 1 vs 0 ng/mL; OR = 1.1; 95% CI = 0.9-1.3; P = 0.45).

CONCLUSIONS

In critically ill patients, higher lorazepam plasma concentrations were associated with delirium, whereas dexmedetomidine plasma concentrations were not. This implies that the reduced delirium risk seen in patients sedated with dexmedetomidine may be a result of avoidance of benzodiazepines, rather than a dose-dependent protective effect of dexmedetomidine.

The pharmacogenomics of severe traumatic brain injury

Pharmacotherapy for traumatic brain injury (TBI) is focused on resuscitation, prevention of secondary injury, rehabilitation and recovery. Pharmacogenomics may play a role in TBI for predicting therapies for sedation, analgesia, seizure prevention, intracranial pressure-directed therapy and neurobehavioral/psychiatric symptoms. Research into genetic predictors of outcomes and susceptibility to complications may also help clinicians to tailor therapeutics for high-risk individuals. Additionally, the expanding use of genomics in the drug development pipeline has provided insight to novel investigational and repurposed medications that may be useful in the treatment of TBI and its complications. Genomics in the context of treatment and prognostication for patients with TBI is a promising area for clinical progress of pharmacogenomics.

Delirium and exposure to psychoactive medications in critically ill adults: A multi-centre observational study

PURPOSE

Investigate the relationship between psychoactive drugs and delirium.

MATERIALS AND METHODS

Prospective observational study of 520 critically ill adult patients admitted ≥24h to 6 intensive care units (ICUs). Data were collected on psychoactive drug exposure, use of sedation administration strategies, and incident delirium (Intensive Care Delirium Screening Checklist score≥4).

RESULTS

Delirium was detected in 260 (50%) patients, median (IQR) duration 2 (1-5) days, and time to onset 3 (2-5) days. Delirious patients received more low-potency anticholinergic (P<0.0001), antipsychotic (P<0.0001), benzodiazepine (P<0.0001) and non-benzodiazepine sedative (P<0.0001), and opioid (P=0.0008) drugs. Primary regression (24-hours preceding drug exposure) revealed no association between any psychoactive drug and delirium. Post-hoc analysis (extended 48-hour exposure) revealed an association between delirium and high-potency anticholinergic (HR 2.45, 95% CI 1.08-5.54) and benzodiazepine (HR 1.08 per 5mg midazolam-equivalent increment, 95% CI 1.04-1.12) drugs. Delirious patients had longer ICU (P<0.0001) and hospital (P<0.0001) length of stay, and higher ICU and hospital mortality (P=0.003 and P=0.007, respectively).

CONCLUSIONS

The identification of psychoactive drugs as modifiable delirium risk factors plays an important role in the management of critically ill patients. This is particularly important given the burden of exposure and combinations of drugs used in this vulnerable patient population.

An observational study examining the effects of a surgically induced inflammatory response on the distribution of morphine and its metabolites into cerebrospinal fluid

PURPOSE

Morphine is administered intravenously for pain management in the perioperative period. The effect of the inflammatory response to surgery on morphine distribution across the blood-brain barrier (BBB) in humans was investigated. We hypothesized that a graded surgically induced, systemic inflammatory response alters cerebrospinal fluid (CSF) levels of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) through a temporary reduction in BBB drug efflux transporter function.

METHODS

We conducted a prospective pharmacokinetic study of the plasma and CSF distribution of the P-glycoprotein (PGP) substrate morphine in 33 patients undergoing open thoracic (n = 18) or endovascular (n = 15) aortic aneurysm repair. Morphine was administered with induction of anesthesia and in the intensive care unit. Plasma and CSF concentrations of interleukin (IL)-6, morphine, M3G, M6G, and albumin were measured prior to surgery (baseline), during surgery, and postoperatively every six hours until removal of the CSF drain. The area under the curve (AUC) was determined for plasma and CSF IL-6, morphine, M3G, and M6G concentrations vs time. The primary endpoint measures were the correlations between the morphine, M6G, and M3G AUC CSF/plasma ratios and systemic inflammation as quantified by the time-normalized IL-6 exposure, which was calculated for each individual by dividing the total exposure (AUC) by time (t). A Bonferroni corrected P < 0.017 indicated a significant correlation.

RESULTS

Plasma and CSF IL-6 concentrations increased postoperatively. The median [interquartile range] IL-6 exposures were significantly higher in the open vs endovascular surgical group for plasma (105 [40-256] pg·mL^-1 vs 29 [16-70] pg·mL^-1, respectively; P = 0.013) and CSF (79 [26-133] pg·mL^-1 vs 16 [9-80] pg·mL^-1, respectively; P = 0.013). For the primary endpoint, the plasma IL-6 AUC/t did not correlate with the CSF accumulation of morphine (r = -0.009; P = 0.96) or M3G (r = 0.37; P = 0.04) when corrected for surgical procedure, age, and sex. There were insufficient data on CSF concentration to complete the primary analysis for M6G.

CONCLUSION

Morphine distribution into the CSF was not significantly altered in patients undergoing thoracic aortic aneurysm repair. This suggests that BBB PGP function may not be affected by the perioperative inflammatory response.

TRIAL REGISTRATION

www.clinicaltrials.gov , NCT 00878371. Registered 7 April 2009.

Direct evidence of central nervous system axonal damage in patients with postoperative delirium: A preliminary study of pNF-H as a promising serum biomarker

INTRODUCTION

Approximately 50-80% patients experience postoperative delirium, an acute cognitive dysfunction associated with prolonged hospitalization, increased mortality, excess healthcare costs, and persistent cognitive impairment. Elucidation of the mechanism of delirium and associated diagnostic and therapeutic measures are urgently required. Here we investigated the role of phosphorylated neurofilament heavy subunit (pNF-H), a major structural protein in axons, as a predictive maker of postoperative delirium.

MATERIAL AND METHODS

Twenty-three patients who underwent surgery for abdominal cancer were screened for postoperative delirium, and they were assessed for its severity using the memorial delirium assessment scale (MDAS) at and 48h after delirium onset. Serum pNF-H levels were also measured at both time points. The patients were divided into two groups according to the presence or absence of pNF-H. Clinical variables were compared between groups using the Mann-Whitney U test, and the relationship between pNF-H levels and delirium severity was analyzed using the exponential curve fitting.

RESULTS

Fifteen of the 23 (65.2%) patients tested positive for pNF-H, and these patients exhibited significantly higher MDAS scores compared with the pNF-H-negative patients only at the onset of delirium. Although the MDAS score significantly improved over time in the positive group, pNF-H positivity persisted. There was a correlation between the maximum pNF-H level and maximum MDAS score (R²=0.31, p=0.013).

CONCLUSIONS

More severe postoperative delirium was directly related to higher serum pNF-H levels, suggesting the potential application of pNF-H as a quantitative biomarker of neural damage in postoperative delirium.

Prognosis of neurologic complications in critical illness

Neurologic complications of critical illness require extensive clinical and neurophysiologic evaluation to establish a reliable prognosis. Many sequelae of intensive care unit (ICU) treatment, such as delirium and ICU-acquired weakness, although highly associated with adverse outcomes, are less suitable for prognostication, but should rather prompt clinicians to seek previously unnoticed persisting underlying illnesses. Prognostication can be confounded by drug administration particularly because its clearance is abnormal in critical illness. Some neurological complications are severe, and can last for months or years after discharge from ICU. The most important ethical aspects regarding neurologic complications in critically ill patients are prevention, recognition, and identification, and prevention of self-fulfilling prophecies. This chapter summarizes the tool of prognostication of major neurological complications of critical illness.

Pharmacogenomics and pharmacogenetics for the intensive care unit: a narrative review

PURPOSE

Knowledge of how alterations in pharmacogenomics and pharmacogenetics may affect drug therapy in the intensive care unit (ICU) has received little study. We review the clinically relevant application of pharmacogenetics and pharmacogenomics to drugs and conditions encountered in the ICU.

SOURCE

We selected relevant literature to illustrate the important concepts contained within.

PRINCIPAL FINDINGS

Two main approaches have been used to identify genetic abnormalities - the candidate gene approach and the genome-wide approach. Genetic variability in response to drugs may occur as a result of alterations of drug-metabolizing (cytochrome P [CYP]) enzymes, receptors, and transport proteins leading to enhancement or delay in the therapeutic response. Of relevance to the ICU, genetic variation in CYP-450 isoenzymes results in altered effects of midazolam, fentanyl, morphine, codeine, phenytoin, clopidogrel, warfarin, carvedilol, metoprolol, HMG-CoA reductase inhibitors, calcineurin inhibitors, non-steroidal anti-inflammatory agents, proton pump inhibitors, and ondansetron. Changes in cholinesterase enzyme function may affect the disposition of succinylcholine, benzylisoquinoline muscle relaxants, remifentanil, and hydralazine. Genetic variation in transport proteins leads to differences in the response to opioids and clopidogrel. Polymorphisms in drug receptors result in altered effects of β-blockers, catecholamines, antipsychotic agents, and opioids. Genetic variation also contributes to the diversity and incidence of diseases and conditions such as sepsis, malignant hyperthermia, drug-induced hypersensitivity reactions, cardiac channelopathies, thromboembolic disease, and congestive heart failure.

CONCLUSION

Application of pharmacogenetics and pharmacogenomics has seen improvements in drug therapy. Ongoing study and incorporation of these concepts into clinical decision making in the ICU has the potential to affect patient outcomes.

Intra-operative events during cardiac surgery are risk factors for the development of delirium in the ICU

BACKGROUND

Risk factors for delirium following cardiac surgery are incompletely understood. The aim of this study was to investigate whether intra-operative pathophysiological alterations and therapeutic interventions influence the risk of post-operative delirium.

METHODS

This retrospective cohort study was performed in a 12-bed cardiosurgical intensive care unit (ICU) of a university hospital and included patients consecutively admitted after cardiac surgery during a 2-month period. The diagnosis of delirium was made clinically using validated scores. Comparisons between patients with and without delirium were performed with non-parametric tests. Logistic regression was applied to identify independent risk factors. Results are given as number (percent) or median (range).

RESULTS

Of the 194 consecutive post-cardiac surgery patients, 50 (26 %) developed delirium during their ICU stay. Univariate analysis revealed that significant differences between patients with and without delirium occurred in the following intra-operative variables: duration of cardiopulmonary bypass (184 [72-299] vs 113 (37-717) minutes, p < 0.001), lowest mean arterial pressure (50 [30-70] vs 55 [30-75] mmHg, p = 0.004), lowest haemoglobin level (85 [56-133] vs 98 [53-150] g/L, p = 0.005), lowest body temperature (34.5 [24.4-37.2] vs 35.1 [23.9-37.2] °C, p = 0.035), highest noradrenaline support (0.11 [0.00-0.69] vs 0.07 [0.00-0.42] μg/kg/minute, p = 0.001), and frequency of red blood cell transfusions (18 [36 %] vs 26 [18 %], p = 0.018) and platelet transfusions (23 [46 %] vs 24 [17 %], p < 0.001). Only platelet transfusions remained an independent risk factor in the multivariate analysis (p < 0.001).

CONCLUSIONS

In patients undergoing cardiac surgery, various intra-operative events, such as transfusion of platelets, were risk factors for the development of a post-operative delirium in the ICU. Further research is needed to unravel the underlying mechanisms.

Evaluation of sedatives, analgesics, and neuromuscular blocking agents in adults receiving extracorporeal membrane oxygenation

PURPOSE

The objective of this study was to evaluate the use of sedative, analgesic, and neuromuscular blocking agents (NMBAs) in patients undergoing extracorporeal membrane oxygenation (ECMO) support.

MATERIALS AND METHODS

This was a 2-year, prospective, observational study of adult intensive care unit patients on ECMO support for more than 48hours.

RESULTS

We analyzed 32 patients, including 15 receiving VA (venoarterial) ECMO and 17 VV (venovenous) ECMO. The median daily dose of benzodiazepines (midazolam equivalents) was 24mg, and the median daily dose of opioids (fentanyl equivalents) was 3875 μg. There was a moderate negative correlation between the day of ECMO and the median daily benzodiazepine dose (r=-0.5515) and a very weak negative correlation for the median daily opioid dose (r=-0.0053). On average, patients were sedated to Richmond Agitation Sedation Scale scores between 0 and -1. Continuous infusions of opioids, benzodiazepines, propofol, dexmedetomidine, and NMBAs were administered on 404 (85.1%), 199 (41.9%), 95 (20%), 32 (6.7%), and 60 (12.6%) ECMO days, respectively. Patients in the VA arm received a continuous infusion opioid (96.4% vs 81.6% days; P<.001) and benzodiazepine (58.2% vs 37.0% days; P<.001) more frequently.

CONCLUSIONS

Patients received relatively low doses of sedatives and analgesics while at a light level of sedation on average. Patients rarely required neuromuscular blockade.

A clinical perspective of sepsis-associated delirium

The term sepsis-associated encephalopathy (SAE) has been applied to animal models, postmortem studies in patients, and severe cases of sepsis. SAE is considered to include all types of brain dysfunction, including delirium, coma, seizure, and focal neurological signs. Clinical data for sepsis-associated delirium (SAD) have been accumulating since the establishment of definitions of coma or delirium and the introduction of validated screening tools. Some preliminary studies have examined the etiology of SAD. Neuroinflammation, abnormal cerebral perfusion, and neurotransmitter imbalances are the main mechanisms underlying the development of SAD. However, there are still no specific diagnostic blood, electrophysiological, or imaging tests or treatments specific for SAD. The duration of delirium in intensive care patients is associated with long-term functional disability and cognitive impairment, although this syndrome usually reverses after the successful treatment of sepsis. Once the respiratory and hemodynamic states are stabilized, patients with severe sepsis or septic shock should receive rehabilitation as soon as possible because early initiation of rehabilitation can reduce the duration of delirium. We expect to see further pathophysiological data and the development of novel treatments for SAD now that reliable and consistent definitions of SAD have been established.

Sedation/drugs used in intensive care sedation

PURPOSE OF REVIEW

There is recognition that the use of sedative drugs in critically ill patients is potentially harmful, particularly in relation to ICU delirium and clinical outcomes. In that context, there is an increasing interest in maintaining light sedation, the use of non-gamma-aminobutyric acid agonist agents and antipsychotics.

RECENT FINDINGS

The sedative drugs currently available have limitations relating to duration of action, cost or variability in response. Recent reviews and meta-analyses comparing sedatives in ICU patients differ in their findings depending on whether trials in elective cardiac surgical patients are included. Dexmedetomidine does appear to reduce the number of ventilator days in the less sick critically ill patient. There is currently no evidence to support the routine use of antipsychotics in ICU patients to prevent or treat delirium, although they will reduce agitation and they appear to be well tolerated when used in the critically ill patient. Sedation protocols and early mobilization reduce the use of sedative drugs and improve some outcomes but are challenging to implement in practice.

SUMMARY

The bedside clinician needs to balance the need to sedate the patient and maintain life-saving support, while keeping their patient responsive, cooperative and pain free.

Benzodiazepine-associated delirium in critically ill adults

PURPOSE

The association between benzodiazepine use and delirium risk in the ICU remains unclear. Prior investigations have failed to account for disease severity prior to delirium onset, competing events that may preclude delirium detection, other important delirium risk factors, and an adequate number of patients receiving continuous midazolam. The aim of this study was to address these limitations and evaluate the association between benzodiazepine exposure and ICU delirium occurrence.

METHODS

In a cohort of consecutive critically ill adults, daily mental status was classified as either awake without delirium, delirium, or coma. In a first-order Markov model, multinomial logistic regression analysis was used, which considered five possible outcomes the next day (i.e., awake without delirium, delirium, coma, ICU discharge, and death) and 16 delirium-related covariables, to quantify the association between benzodiazepine use and delirium occurrence the following day.

RESULTS

Among 1112 patients, 9867 daily transitions occurred. Benzodiazepine administration in an awake patient without delirium was associated with increased risk of delirium the next day [OR 1.04 (per 5 mg of midazolam equivalent administered) 95 % CI 1.02-1.05). When the method of benzodiazepine administration was incorporated in the model, the odds of transitioning to delirium was higher with benzodiazepines given continuously (OR 1.04, 95 % CI 1.03-1.06) compared to benzodiazepines given intermittently (OR 0.97, 95 % CI 0.88-1.05).

CONCLUSIONS

After addressing potential methodological limitations of prior studies, we confirm that benzodiazepine administration increases the risk for delirium in critically ill adults but this association seems to be limited to continuous infusion use only.

Pharmacokinetic considerations for drugs administered in the critically ill

Significant physiological changes are common among critically ill patients. This case-based review describes the consequences of these changes on the selection and dosing of medications.

Major publications in the critical care pharmacotherapy literature: January-December 2013

PURPOSE

Ten recently published articles with important implications for critical care pharmacotherapy are summarized.

SUMMARY

The Critical Care Pharmacotherapy Literature Update (CCPLU) group is a national assembly of experienced intensive care unit (ICU) pharmacists across the United States. Group members monitor 25 peer-reviewed journals on an ongoing basis to identify literature relevant to pharmacy practice in the critical care setting. After evaluation by CCPLU group members, selected articles are chosen for summarization and distribution to group members nationwide based on (1) applicability to critical care practice, (2) relevance to pharmacy practitioners, and (3) quality of evidence or research methodology. Hundreds of relevant articles were evaluated by the group during the period January-December 2013, of which 98 were summarized and disseminated nationally to CCPLU group members. Among those 98 publications, 10 deemed to be of particularly high utility to critical care practitioners were included in this review. The 10 articles address topics such as rapid lowering of blood pressure in patients with intracranial hemorrhage, adjunctive therapy to prevent renal injury due to acute heart failure, triple-drug therapy to improve neurologic outcomes after cardiac arrest, and continuous versus intermittent infusion of β-lactam antibiotics in severe sepsis.

CONCLUSION

There were many important additions to the critical care pharmacotherapy literature in 2013, including an updated guideline on the management of myocardial infarction and reports on advances in research focused on improving outcomes in patients with stroke or cardiac arrest and preventing the spread of drug-resistant pathogens in the ICU.

Transporter-Mediated Disposition of Opioids: Implications for Clinical Drug Interactions

Opioid-related deaths, abuse, and drug interactions are growing epidemic problems that have medical, social, and economic implications. Drug transporters play a major role in the disposition of many drugs, including opioids; hence they can modulate their pharmacokinetics, pharmacodynamics and their associated drug-drug interactions (DDIs). Our understanding of the interaction of transporters with many therapeutic agents is improving; however, investigating such interactions with opioids is progressing relatively slowly despite the alarming number of opioids-mediated DDIs that may be related to transporters. This review presents a comprehensive report of the current literature relating to opioids and their drug transporter interactions. Additionally, it highlights the emergence of transporters that are yet to be fully identified but may play prominent roles in the disposition of opioids, the growing interest in transporter genomics for opioids, and the potential implications of opioid-drug transporter interactions for cancer treatments. A better understanding of drug transporters interactions with opioids will provide greater insight into potential clinical DDIs and could help improve opioids safety and efficacy.

Prevalence, risk factors, and outcomes of delirium in mechanically ventilated adults

OBJECTIVE

Delirium is common during critical illness and associated with adverse outcomes. We compared characteristics and outcomes of delirious and nondelirious patients enrolled in a multicenter trial comparing protocolized sedation with protocolized sedation plus daily sedation interruption.

DESIGN

Randomized trial.

SETTING

Sixteen North American medical and surgical ICUs.

PATIENTS

Four hundred thirty critically ill, mechanically ventilated adults.

INTERVENTIONS

All patients had hourly titration of opioid and benzodiazepine infusions using a validated sedation scale. For patients in the interruption group, infusions were resumed, if indicated, at half of previous doses. Delirium screening occurred daily; positive screening was defined as an Intensive Care Delirium Screening Checklist score of 4 or more at any time.

MEASUREMENTS AND MAIN RESULTS

Delirium was diagnosed in 226 of 420 assessed patients (53.8%). Coma was identified in 32.7% of delirious compared with 22.7% of nondelirious patients (p = 0.03). The median time to onset of delirium was 3.5 days (interquartile range, 2-7), and the median duration of delirium was 2 days (interquartile range, 1-4). Delirious patients were more likely to be male (61.1% vs 46.6%; p = 0.005), have a surgical/trauma diagnosis (21.2% vs 11.0%; p = 0.030), and history of tobacco (31.5% vs 16.2%; p = 0.002) or alcohol use (34.6% vs 20.9%; p = 0.009). Patients with positive delirium screening had longer duration of ventilation (13 vs 7 d; p < 0.001), ICU stay (12 vs 8 d; p < 0.0001), and hospital stay (24 vs 15 d; p < 0.0001). Delirious patients were more likely to be physically restrained (86.3% vs 76.7%; p = 0.014) and undergo tracheostomy (34.6% vs 15.5%; p < 0.0001). Antecedent factors independently associated with delirium onset were restraint use (hazard ratio, 1.87; 95% CI, 1.33-2.63; p = 0.0003), antipsychotic administration (hazard ratio, 1.67; 95% CI, 1.005-2.767; p = 0.047), and midazolam dose (hazard ratio, 0.998; 95% CI, 0.997-1.0; p = 0.049). There was no difference in delirium prevalence or duration between the interruption and control groups.

CONCLUSION

In mechanically ventilated adults, delirium was common and associated with longer duration of ventilation and hospitalization. Physical restraint was most strongly associated with delirium.