Delirium Among Adults Undergoing Solid Organ Transplantation

Abstract

Purpose of Review:

To summarize the research on post-operative delirium among patients undergoing solid organ transplantation in efforts to improve recognition, evaluation, and management, as well as highlight areas for future research.

Recent Findings:

Delirium is a common complication in patients with organ failure before and after undergoing solid organ transplant (range: 4.7–47%). However, it is frequently unrecognized and underdiagnosed—even among those closely monitored after major surgery—given that its manifestation is often variable and inconsistent. Delirium has multifactorial etiologies comprising of a complex mix of predisposing recipient, donor, and transplant factors, as well as intraoperative and perioperative factors. Evidence suggests that delirium risk increases with presence of a greater number of such risk factors, and can lead to adverse outcomes such as increased hospital length of stay, time in the ICU, time on mechanical ventilators, graft dysfunction, graft loss, and mortality. Though no trials have been conducted among transplant populations specifically, delirium has been shown to be preventable among hospitalized older adults generally. Multicomponent, primary prevention strategies designed to target multiple risk factors of delirium, such as cognitive impairment, sleep deprivation, immobility, visual impairment, hearing impairment, and dehydration, have been identified as most effective. Whether these approaches translate to improvements in quality of life and long-term health outcomes among patients with organ failure before and after transplantation is yet to be determined.

Summary:

Delirium is an important, common, yet potentially preventable complication among patients with organ failure. Future studies are needed to test the efficacy of multicomponent, primary prevention strategies on long-term health outcomes among these vulnerable populations.

INTRODUCTION

Delirium Among Older Adults

Delirium is an important, common complication that has been described since the era of Hippocrates in the 5^th century BC; yet, to this day, it is still frequently misunderstood, under- and mis-diagnosed, as well as mismanaged.¹ Modern characterization of delirium defines it as an acute decline in cognitive function and attention as a consequence of a noxious insult, such as drug toxicity, metabolic imbalances (e.g., low sodium or low calcium), medical conditions (e.g., stroke, heart attack, worsening lung or liver disease, and injurious falls), or surgery.^1–6 Despite underreporting, identified delirium occurrence rates among older adults have ranged from 14–56%,^7,8 contributing to mounting economic and societal costs. Delirium occurrence increases with the risk of the procedure or surgery, such that incidence is typically higher among patients undergoing more invasive, high-risk surgeries compared to patients seeking other medical needs or undergoing less invasive procedures.⁹ Ultimately, delirium can lead to death, with post-delirium mortality rates ranging from 25–33%.^7,8

Though delirium has been extensively studied among hospitalized older adults generally,⁹ delirium manifestation specifically among patients of all ages undergoing solid organ transplantation is likely to be unique given history of chronic disease, difficult treatments (e.g., dialysis), and the event of undergoing major surgery, which requires heavy anesthetics and high-doses of neurotoxic immunosuppressive agents post-transplantation. Below we summarize: 1) the tools used to screen for delirium and their applicability to patients undergoing organ transplantation, 2) the epidemiology of delirium among organ transplant patients across sub-specialties, and 3) what interventions may apply to organ transplant candidates and recipients for prevention and/or treatment.

Diagnostic Tools for Delirium Assessment

Delirium is a clinical diagnosis recognized through brief cognitive screenings in combination with perceptive clinical observation. The official definition of delirium based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders requires a disturbance in attention and awareness that develops acutely and tends to fluctuate (Table 1).¹⁰ Among the available diagnostic instruments, the Confusion Assessment Method (CAM)⁶ is identified as the most widely used tool,⁹ with up to 95% sensitivity when paired with the mini-mental state exam (MMSE), a brief screening assessment for global cognitive function. It is considered to be most useful not only for its accuracy, but also for its succinctness and ease of use among clinicians and lay interviewers.¹¹ This attribute distinguishes the CAM from other popular instruments, like the Delirium Rating Scale-Revised-98 (DRS-R-98).¹² Although the DRS-R-98 is a more comprehensive instrument useful for diagnosis, severity rating, and sensitivity to change—making it particularly useful for monitoring patients over a period of time—it was designed to be used only by trained and experienced experts.¹¹ While the DRS-R-98 can take 20–30 minutes for scoring in addition to 1–2 hours for gathering information needed to rate items (such as family, staff interviews, and medical records reviews) by a trained psychiatrist,¹² the CAM can be administered in just 5 minutes by non-psychiatric physicians, nurses, or staff interviewers.

Table 1.

Diagnostic criteria for delirium.

DSM V a

Presence of delirium requires all criteria to be met.

• Disturbance in attention and awareness

• Disturbance develops acutely and tends to fluctuate in severity

• At least one additional disturbance in cognition

• Disturbances are not better explained by a pre-existing dementia

• Disturbances do not occur in the context of a severely reduced level of arousal or coma

• Evidence of an underlying organic cause or causes

Confusion Assessment Method (CAM) b

Presence of delirium requires features 1 and 2 and either 3 or 4).

• Acute onset of change in mental status and fluctuating course (feature 1)

• Inattention (feature 2)

• Disorganized thinking (feature 3)

• Altered level of consciousness (feature 4)

Delirium Rating Scale – Revised 98 (DRS-R-98) c

16-item clinician (3 diagnostic items plus 13 severity items for maximum rating of 46 points) symptoms rating scale administered by trained expert.

• Sleep-wake disturbance

• Perceptual disturbance and hallucination

• Delusions

• Lability of affect

• Language

• Thought process abnormalities

• Motor agitation

• Motor retardation

• Orientation

• Attention

• Short-term memory

• Long-term memory

• Visuospatial ability

• Temporal onset of symptoms

• Fluctuation of symptom severity

• Physical disorder

^aAdapted from the Diagnostic and statistical Manual of Mental Disorders, fifth edition (DSM-V).¹⁰

^bAdapted from Inouye et al. 1990.⁶

^cAdapted from Trzepacz et al. 2001.¹²

Even with its brevity, the CAM measures delirium presence, severity, and fluctuation, capturing nine key delirium characteristics, including acute onset, inattention, disorganized thinking, altered level of consciousness, disorientation, memory impairment, perceptual disturbances, psychomotor agitation or retardation, and altered sleep-wake cycle (Figure 1).⁶ Its diagnostic algorithm is based on four cardinal features including: 1) acute onset of mental status change and fluctuating course, 2) inattention, 3) disorganized thinking, and 4) altered level of consciousness; diagnosis requires both features (1) and (2) as well as either (3) or (4). The CAM can be used to capture subtypes, including hypoactive, hyperactive, or mixed-type delirium.

Figure 1.

Nine key characteristics of delirium captured by the Confusion Assessment Method.

Given the risk of ICU-related morbidities post-transplantation among solid organ recipients, including risk of complications related to surgical procedures, immunosuppressive therapy, and infections,^13–15 delirium screening instruments for ICU settings should be considered. CAM for ICU assessment (CAM-ICU) was specifically developed for use in non-verbal (mechanically ventilated) patients in ICU settings,^16,17 and takes up to 2 minutes to administer.¹¹ CAM-ICU has a higher sensitivity (95%−100%) and specificity (93–98%) compared to other popular scales developed for ICU settings, like the Nursing delirium Screening Scale (sensitivity: 85.7%; specificity: 86.8%).¹⁸ Though non-verbal ratings have lower sensitivity (73%) compared to verbal ratings using the CAM-ICU, high specificity is maintained (100%).¹⁹ Nonetheless, when feasible, verbal responses for the CAM-ICU are encouraged in order to avoid under-recognition of delirium cases.

Delirium Occurrence Among Populations with Organ Failure Pre-Transplantation

Comparing rates of delirium occurrence across different organ failure subspecialties is particularly challenging given the wide variety of tools used to identify delirium within and across these populations. Nevertheless, delirium is strikingly common among patients of all ages with organ failure across each of the subspecialties. Reported occurrence ranges from 15% among patients with end-stage kidney disease (ESKD) undergoing hemodialysis (diagnosed by psychiatrists using the DSM-IV-TR criteria),²⁰ to 21% among patients with end-stage liver disease using the CAM and DRS-R-98 assessments,²¹ 23% among patients with acute heart failure using the Intensive Care Delirium Screening Checklist,²² and 23% among patients with chronic obstructive pulmonary disease using the CAM-ICU assessment.²³

Prevalence of Post-Operative Delirium Among Solid Organ Transplant Recipients

Despite major advances in the detection, diagnosis, and etiologies of delirium among hospitalized older adults,⁹ it still remains heavily underdiagnosed, even among those monitored closely after having undergone major surgery like solid organ transplantation. Among 125,304 identified kidney transplant recipients between 1999 and 2014, for instance, only 0.8% had a delirium claim; this is a dramatic underestimation from the identified 4.7% in a cohort study of 893 kidney transplant recipients from the Johns Hopkins Hospital between 2009 and 2017 using a validated, chart-based method of detection.²⁴ Underdiagnosis is often attributable to inconsistent screening, as well as difficulty in diagnosis given the varying and inconsistent manifestations of delirium. Although, conceptually, delirium is thought to be manifested as a state of agitation, hallucination, and delusion, hyperactive delirium represents only about 25% of cases.^1,9 Patients with hypoactive delirium, manifested as a state of reduced motor activity, lethargy, and withdrawal, affects approximately 50% of cases, and is often associated with poorer outcomes, likely because it is often overlooked or is less frequently recognized.^25,26

Despite underdiagnosis, delirium is common among the different solid organ transplant subspecialities, ranging from 4.7% to 47% (Table 2). Notably, a majority of studies have been conducted among patients undergoing liver transplant, and a majority used retrospective chart-based methods for identifying delirium as opposed to direct measures captured prospectively. Among recently published studies in solid organ transplantation, liver transplant recipients had the highest prevalence of delirium, likely due to the higher prevalence of studies conducted in ICU settings, though it is important to note that differences may also be attributable to distinct risk factor profiles (e.g., ascites), and tools used to define delirium cases with varying sensitivities and specificities (Table 2).

Table 2.

Select cohort studies of post-transplant delirium in solid organ transplantation published within the past two decades (2000–2020).

Organ	Reference	Demographics	% with and Measures of Delirium	Findings Associated with Post-Transplant Delirium
				Pre-Transplant Risk Factors	Post-Transplant Outcomes
Liver	Yoon et al. (2009)	N=368 Mean Age: % female	40% developed delirium (chart review)	History of alcohol consumption (OR=2.04; 95% CI: 1.12,3.72) History of hepatic encephalopathy (OR=2.54; 95% CI: 1.46,4.41) MELD score (OR= 1.03; 95% CI: 1.00,1.06)	n/a
	Lescot et al. (2013)	N=281 Mean Age: 58 29.5% female	10% physician diagnosis based on DSM IV criteria	Intraoperative transfusion (packed RBC) (OR=1.15, 95%CI: 1.01, 1.18) Pretransplant renal replacement therapy (OR=13.12, 95%CI: 2.82, 72.12) APACHE II score (OR per unit increase=1.10, 95%CI: 1.03, 1.29)	Longer hospital LOS (HR=2.37, 95%CI: 1.54, 3.85) In-hospital mortality (HR=4.30 95%CI: 1.62, 10.34) One-year mortality (HR=2.90, 95%CI: 1.29, 5.91)
	Wang et al. (2014)	N=78 Mean Age: 53.4 25.6% female	47% Richmond Agitation-Sedation Scale (RASS) and CAM-ICU	History of alcohol abuse (OR=6.40, 95%CI: 1.85, 22.06) Preoperative hepatic encephalopathy (OR = 4.45, 95% CI: 1.36,14.51) APACHE II score ≥16 (OR= 1.73, 95% CI: 1.71,2.56) Intubation duration ≥5 days (OR= 1.81, 95% CI: 1.52,2.23)	Longer LOS in ICU (39.8 vs. 29.3; p=0.03)
	Beckmann et al. (2016)	N=42 Mean Age: 55 31% female	45% developed delirium with median duration of 5 days (Care Delirium Screening Checklist and Delirium Observation Screening Scale	n/a	Longer ICU stay (8 vs. 2 days, p<0.001) Longer hospital stays (32 vs. 14 days, p<0.001) Shorter survival (585 vs. 742 days, Breslow test p=0.046)
	Oliver et al. (2017)	N= 181 Mean Age: 57–58 66.9% female	21% developed delirium (EMR chart-abstractions)	Antidepressant use (OR=3.34, 95%CI: 1.29,8.70) Hospital admission for encephalopathy (OR=4.39, 95%CI: 1.77,10.9)	Longer time on mechanical ventilation (2.0 vs. 1.3 days, p=0.01) Longer LOS in ICU (4.6 vs. 2.7 days, p=0.01) Longer hospital LOS (27.6 vs. 11.2 days, p=0.003). Higher 6-month mortality (13.2% vs. 1.4%, p=0.003)
	Bhattacharya et al. (2017)	N=144 Mean Age: 51.8 33.3% female	25% developed delirium, average duration 4.65 days (screened retrospectively using Delirium Observation Screening scale 8)	Older age (56.7 vs. 50.1; p=0.01) Increased MELD score (26.8 vs. 20.8; p=0.02) Longer pretransplant hospital LOS (20.9 vs. 6.4; p=0.003) Alcohol ingestion as cause of liver failure (33.3% vs. 16.7%; p=0.03)	Longer hospital LOS (27.6 vs. 14.4 days; p=0.001) Longer ICU LOS (9.5 vs. 4.5 days; p=0.001)
	Lee et al. (2018)	N=253 Median Age: 54 29.6% female	17% developed delirium (CAM-ICU)	Higher preoperative MELD group (15–24vs.<15: OR=4.10, 95%CI: 1.67,10.09, ≥25vs.<15: OR=5.59, 95%CI: 2.06, 15.19) Higher APACHE II scores (OR=5.59, 95%CI: 2.06, 15.19) Reintubation (OR=6.46, 95%CI: 2.10, 19.88)	Mechanical ventilation duration (10 vs. 5 hours; p=0.04) ICU LOS (5.8 vs. 4.1 days; p=0.004) Hospital LOS (38 vs. 21 days; p=0.004) No difference in 1-year mortality (p=0.06)
	Chen et al. (2020)	N=159 Mean Age: 48 15.7% female	26% developed delirium (CAM-ICU)	Preoperative ammonia (≥46 vs <46 μmol/L: OR=3.51, 95%CI:1.31,9.46) MELD score (≥15 vs.<15; OR=3.33, 95%CI: 1.27, 8.79) Presence of hepatic encephalopathy (OR=3.30, 95% CI: 1.20, 9.07) AST on day 1 postoperatively (OR=1.33, 95%CI: 1.06, 1.68) Anhepatic period (OR=1.04, 95%CI: 1.02, 1.06)	Longer intubation time (2925.0 vs 1410.0 min, P<0.01), ICU LOS (6 vs 4 days, P<0.01) Increased medical costs (43.96 vs 33.74 ten thousand yuan, p<0.01)
	Park et al. (2020)	N=325 Mean age: 53.4 72.3% female	21% developed delirium (retrospective chart review)	Preoperative bilirubin<3.5 (OR=2.86, 95%CI: 1.38, 5.94) Body mass index (OR=0.85, 0.77, 0.94) Alcoholic Liver Disease (OR=1.63, 0.85, 3.13) Diuretic use (OR=2.18, 95%CI: 1.11, 4.30) Preoperative Creatinine (OR=1.50, 95%CI: 1.10, 2.06)	n/a
Kidney	Haugen et al. (2018)	N=893 Mean Age: 52.5 39.0% female	4.7% developed delirium; 19% hypoactive, 16.7% hyperactive; 27% mixed type (chart abstraction)	Older age (OR=2.65, 95%CI: 1.36, 5.18) Multimorbidity (OR=1.93, 95%CI: 1.01, 3.71) Frailty (OR=2.05, 95%CI: 1.02, 4.13)	≥2 week LOS (OR=5.42, 95%CI: 2.76, 10.66) Institutional discharge (OR=22.41, 95%CI: 7.85, 63.98) Graft loss (HR=2.73, 95%CI: 1.14, 6.53) Mortality (HR=3.12, 95%CI: 1.76, 5.54)
Lung	Smith et al. (2015)	N=63 Mean Age: 52.7 65% female	37% developed delirium (CAM and DRS-R-98)	Better pre-transplant cognitive performance associated with reduced delirium incidence (OR=0.69, 95%CI: 0.48, 0.99)	Longer hospital LOS (p=0.01)
	Smith et al. (2016)	N=63 Mean Age: 52.7 65% female	37% developed delirium (CAM and DRS-R-98)	Lower cerebral perfusion pressure associated with: 1) developing delirium:  (OR=2.08 per 10mmHG decrease, 95%CI: 1.02, 4.24) 2) delirium duration:  (OR=1.7 days longer per 10mmHG decrease, 95%CI: 1.1–2.7); and 3) greater delirium severity  (difference=−0.81, 95%CI: −1.47, −0.15)	Primary graft dysfunction grade 0/1, 2 or 3 associated with delirium development (OR=3.38, 95%CI: 1.34, 8.56) Longer time in ICU associated with delirium duration (difference=0.51 days, 95%CI: 0.06, 0.95) & delirium severity (difference=0.90, 95%CI: 0.31, 1.49)
	Sher et al. (2017)	N=163 Mean Age: 50.8 41.7% female	44% developed delirium within 30 days post-transplant (EMR chart-abstractions)	Obesity (OR=6.35, 95%CI: 1.61–24.98)	Early-onset delirium was associated with: longer mechanical ventilation duration (p=0.001); ICU LOS (p<0.001), and hospital LOS (p=0.005). Ever-onset delirium was associated with longer ICU (p<0.001) and hospital LOS (p<0.001). Delirium was not associated with one-year mortality (early-onset HR 1.65, 95% CI 0.67–4.03; ever-onset HR 1.70, 95% CI 0.63–4.55).
Heart	Diederik van de Beek et al. (2008)	N=313 Median Age: 52 % female n/a	9% (retrospective chart-review)	n/a	Delirium not related to 1-year mortality (p>0.79)

Abbreviations: 95%CI, 95% confidence interval; APACHE, Acute Physiology and Chronic Health Evaluation; AST, Aspartate aminotransferase; CAM, Confusion Assessment Method; DRS, Delirium Rating Scale; ICU, intensive care unit; LOS, length of stay; OR, odds ratio; HR, hazard ratio;

Pre-Transplant Risk Factors of Delirium

Delirium is rarely caused by a single factor; rather, it is recognized as having multifactorial etiologies, resulting from a combination of predisposing risk factors, as well as intraoperative and perioperative insults.^27,28 Though fewer studies have been conducted specifically among patients with organ failure and/or solid organ transplant recipients, findings point to similar patterns among those vulnerable populations (Figure 2). Older age was a common risk factor for delirium occurrence prior to transplantation among patients with acute heart failure and end-stage kidney disease,^20,22 as well as for delirium occurrence post-transplantation among organ recipients (Table 2). Other identified risk factors among patients with acute heart failure include history of cerebrovascular disease (OR: 2.13, 95% CI: 1.36–3.35), log transformed B-type natriuretic peptide (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).²²

Figure 2. Multifactorial model of delirium among patients undergoing solid organ transplantation.

Adapted from Inouye et al. 2014.¹

Notably, for solid organ recipients, medication use, history of alcohol consumption, history of hepatic encephalopathy, disease severity, and comorbidities were associated with greater risk of delirium (Table 2). However, potentially modifiable, delirium-associated risk factors identified among hospitalized older adults generally, including cognitive impairment, sleep deprivation, immobility, visual impairment, hearing impairment, and dehydration,^28–32 have not been thoroughly examined among solid organ recipients, but should be considered for future study. Importantly, among hospitalized older adults generally, delirium risk increases with the number of risk factors present, which is critical to consider in parallel with the distinctly vulnerable health risk profiles of organ failure patients. This stresses the need to identify multicomponent strategies aimed at reducing the number of risk factors among organ failure patients and solid organ recipients³² with the goal of preventing delirium among these uniquely vulnerable populations.

Consequences of Pre- and Post-Solid Organ Transplant Delirium

Older surgical patients with delirium experience greater functional decline, longer length of stay, mortality, and higher health care costs.^{1–5,33–41} These findings are consistent for patients with organ failure, as well as patients who undergo solid organ transplant (Table 2). Delirium among patients with acute heart failure (n=611, mean age=75.2, 39% female), for example, was associated with worsening heart failure during pre-transplant hospitalization (OR=2.44, 95%CI: 1.27–4.63).²² Delirium was also associated with approximately a 2-fold risk of mortality for patients with acute heart failure (HR=2.38, 95%CI: 1.30–4.35)²² as well as patients with ESKD undergoing hemodialysis (HR=1.96, 95%CI: 1.32, 2.90).²⁰

Risk of adverse outcomes among those who develop delirium is especially high for solid organ recipients, particularly for abdominal organ transplant recipients. Liver transplant recipients who developed delirium were reported to have nearly a 3-fold increase (HR=2.90, 95%CI: 1.29, 5.91) in one-year mortality risk and over a 4-fold increase in in-hospital mortality risk (HR=4.30, 95%CI: 1.62, 10.24) compared to those without delirium.⁴² These findings were consistent for kidney transplant recipients (mortality risk HR=3.12, 95%CI: 1.76, 5.54),²⁴ but not for lung transplant³⁹ nor heart transplant recipients⁴³ (Table 2); however, non-significant findings may be a result of lack of power in the latter populations. Additionally, among lung and kidney transplant recipients, delirium was associated with over a 3-fold likelihood of primary graft dysfunction (OR=3.38, 95%CI: 1.34, 8.56)⁴⁴ and over a 2-fold risk of graft loss (HR=2.75, 95%CI: 1.14, 6.53),²⁴ respectively. For liver, kidney, and lung recipients, delirium was also associated with greater length of stay in the hospital, ICU, and/or time on mechanical ventilation, leading to increased medical costs (Table 2).

Interventions to Prevent and Treat Delirium

Among older adults generally, delirium is often preventable.⁴⁵ Notably, current evidence does not support the use of antipsychotics for prevention or treatment of delirium.⁴⁶ Rather, multicomponent, non-pharmacologic approaches aimed at targeting known delirium risk factors have been identified as most effective for preventing delirium among older adults generally. Multicomponent, non-pharmacologic approaches for delirium prevention may include and target: feeding assistance, fluid repletion, vision and hearing, sleep enhancement, early mobilization, infection prevention, pain management, hypoxia protocol, cognitive stimulation, and psychoactive medication protocol (Table 3).⁴⁷

Table 3.

Multicomponent, nonpharmacologic approaches for delirium prevention. Adapted from Oh et al. 2017.⁴⁷

Approach	Description
Feeding assistance	Follow general nutrition guidelines throughout the day. Ensure proper fit of dentures if applicable. Promote eating with others if possible.
Fluid repletion	Ensure plenty of fluids are taken throughout the day to avoid dehydration. Seek advice regarding fluid balance for patients with comorbidities such as heart failure and renal disease.
Vision and hearing	Ensure hearing aids and glasses are available if needed.
Sleep enhancement	Use techniques to promote relaxation and sufficient sleep such as avoiding medical/nursing procedures during sleep, scheduling medications to avoid disturbed sleep, and reducing noise at night.
Early mobilization	Promote early postoperative mobilization, and encourage regular ambulation. Keep walking aides nearby (such as canes or walkers). Encourage patient activity and range-of-motion exercises.
Infection prevention	Look for and treat infections. Avoid unnecessary catheterization. Implement infection-control procedures.
Pain management	Assess for pain, especially inpatients with communication difficulties. Monitor pain management in those with known or suspected pain.
Hypoxia protocol	Assess for hypoxia and oxygen saturation.
Cognitive stimulation	Stimulate the mind by promoting daily socialization from family and friends, reading, listening to music, engaging in challenging activities/games. Providing calendars, signs, and clocks that help orient patients to the time, day, month, and year.
Psychoactive medication protocol	Review medication lists for both types and number of medications.

The Hospital Elder Life Program (HELP) is one such multicomponent intervention strategy designed to target six risk factors for delirium, including cognitive impairment, sleep deprivation, immobility, visual impairment, hearing impairment, and dehydration.⁴⁸ By targeting these key risk factors, the program aims to 1) maintain physical and cognitive function throughout hospitalization, 2) maximize independence at discharge, 3) assist with transition from hospital to home, and 4) prevent unplanned readmission.⁴⁸ HELP was found to reduce odds of developing delirium (matched OR=0.60, 95%CI: 0.39, 0.92), as well as reduce the number of days with delirium (105 vs. 161; p=0.02) and total number of delirium episodes (62 vs. 90; p=0.03), but had no effect on delirium severity or recurrence rates,³² emphasizing the importance of primary prevention.

FUTURE RESEARCH

It remains uncertain whether systematic identification of delirium improves outcomes among patients undergoing organ transplantation, and whether classification of delirium subtypes, severity, and duration can enhance risk stratification. While guidelines for the prevention and management of delirium in hospitalized older adults have been developed by the United Kingdom National Institute for Health and Care Excellence (NICE)⁴⁹ and the American Geriatrics Society,⁵⁰ little data exists from randomized controlled trials among patients undergoing organ transplantation. Such studies specifically designed to test whether early diagnosis of delirium, treatment of potential contributing factors, and optimized management can improve post-transplant outcomes are needed. Potential interventions specific for transplant patients, such as changes to immunosuppression regimens, should also be considered.

CONCLUSIONS

The presence of delirium is common among solid organ transplant recipients and is associated with high morbidity and mortality post-transplantation. Careful evaluation of potential reversible causes and assessment of proactive prevention strategies aimed at reducing delirium severity and duration are needed to ensure patient safety and potentially improve outcomes among patients undergoing organ transplantation.