Delirium is independently associated with increased mortality, short and long term morbidity, and greater health care costs.
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The prevalence of delirium in patients admitted to an intensive care unit (ICU) varies widely, with reports of between 16% and 89% depending on how the diagnosis is made, the type of ICU and the geographical region studied.
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Girard TD, Exline MC, Carson SS, et al. Haloperidol and ziprasidone for treatment of delirium in critical illness. N Engl J Med 2018; 379: 2506-16.
Mitchell ML, Shum DHK, Mihala G, et al. Long-term cognitive impairment and delirium in intensive care: A prospective cohort study. Aust Crit Care 2018; 31: 204-11.
Girard TD, Thompson JL, Pandharipande PP, et al. Clinical phenotypes of delirium during critical illness and severity of subsequent long-term cognitive impairment: a prospective cohort study. Lancet Respir Med 2018; 6: 213-22.
Reade MC, Finfer S. Sedation and delirium in the intensive care unit. N Engl J Med 2014; 370: 444-54.
Holmes NE, Amjad S, Young M, et al. Using language descriptors to recognise delirium: a survey of clinicians and medical coders to identify delirium-suggestive words. Crit Care Resusc 2019; 21: 299-302.
Patel MB, Bednarik J, Lee P, et al. Delirium monitoring in neurocritically ill patients: a systematic review. Crit Care Med 2018; 46: 1832-41.
Australian and New Zealand data from a 2009 point prevalence study reported that routine delirium assessment occurred in only 3% of patients, with 9% of all patients identified as delirious and 7% of all patients requiring physical restraints.
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Since this study was published, international clinical practice guidelines have recommended that all critically ill adults should be regularly assessed for delirium using a validated tool.
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Moreover, preventing delirium and managing cognitive impairment is now a component of the Australian Commission on Safety and Quality in Health Care hospital accreditation.
Elliott D, Aitken LM, Bucknall TK, et al. Patient comfort in the intensive care unit: a multicentre, binational point prevalence study of analgesia, sedation and delirium management. Crit Care Resusc 2013; 15: 213-9.
Devlin JW, Skrobik Y, Gelinas C, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU. Crit Care Med 2018; 46: e825-73.
There is limited evidence to guide treatment of delirious critically ill patients.
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Despite the lack of evidence to support the administration of drugs, international data suggest that antipsychotics are frequently administered; for example, in the United States, one in ten patients in the ICU is reported to receive an antipsychotic drug for either prevention or treatment of delirium.
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Use of physical restraint is controversial, with almost no evidence supporting or refuting its safety and effectiveness, and widespread variations in practice worldwide.
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Burry L, Hutton B, Williamson DR, et al. Pharmacological interventions for the treatment of delirium in critically ill adults. Cochrane Database Syst Rev 2019; (9): CD011749.
Burry L, Hutton B, Williamson DR, et al. Pharmacological interventions for the treatment of delirium in critically ill adults. Cochrane Database Syst Rev 2019; (9): CD011749.
Swan JT, Fitousis K, Hall JB, et al. Antipsychotic use and diagnosis of delirium in the intensive care unit. Crit Care 2012; 16: R84.
Devlin JW, Skrobik Y, Gelinas C, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU. Crit Care Med 2018; 46: e825-73.
Given the paucity of recent local data, changes to hospital accreditation, and international data suggesting widespread use of antipsychotic drugs in the critically ill, we collected data in the 2019 Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS-CTG) Point Prevalence Program
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to provide up-to-date clinical practice evidence. We hypothesised that the majority of patients in the ICU would receive at least one formal assessment for delirium per day and the use of antipsychotic drugs and physical restraints would be limited to those patients with established hyperactive delirium.
Thompson K, Hammond N, Eastwood G, et al. The Australian and New Zealand Intensive Care Society Clinical Trials Group Point Prevalence Program, 2009–2016. Crit Care Resusc 2017; 19: 88-93.
Methods
We conducted a multicentre observational point prevalence study across 44 Australian and New Zealand adult ICUs as part of the Point Prevalence Program coordinated by the George Institute for Global Health and ANZICS-CTG.
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Human research ethics committee or institutional approval for a waiver of individual patient consent was obtained for all participating sites.
Thompson K, Hammond N, Eastwood G, et al. The Australian and New Zealand Intensive Care Society Clinical Trials Group Point Prevalence Program, 2009–2016. Crit Care Resusc 2017; 19: 88-93.
The point prevalence data were recorded for all adult patients in a bed at participating ICUs at 10:00 hours on one of three assigned study days in June 2019. Study data were collected at each site and entered into an electronic data capture system (REDCap)
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hosted at the George Institute for Global Health. In addition to clinical and demographic information at ICU admission, data collected for the study day included whether the patient was assessed as delirious at any point during the study day, the type of delirium and the method of delirium assessment used for the first delirium status, the highest and lowest Richmond Agitation Sedation Scale (RASS) score recorded, administration of antipsychotic or specific α-2 agonist drugs (dexmedetomidine or clonidine), and whether the patient was physically restrained at any time during the study day. Data collectors were not asked to speculate as to why any particular drug was administered. In addition, patient outcome data were reported at day 28 (counting the study day as day 1). Questions from the case report form are available in the Online Appendix. At an institutional level, sites also recorded if their ICU had a documented protocol, policy or guideline for the daily assessment of delirium in patients and, additionally, if their site had a document for delirium management.
Harris PA, Taylor R, Thielke R, et al. Research electronic data capture (REDCap) — a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform 2009; 42: 377-81.
Statistical analysis
Group comparison were performed using χ2 tests for equal proportion, Student t test for normally distributed data, and Wilcoxon rank sum tests otherwise, with results reported as count (percentage), mean (standard deviation) and median (interquartile range) respectively. No imputation has been used for missing data, with missingness indicated using a denominator to designate availability. Analysis was conducted using SAS version 9.4 (SAS Institute, Cary, NC, USA), and a two-sided P ≤ 0.05 was used to indicate statistical significance.
Results
A total of 44 ICUs in Australia (82%, 36/44) and New Zealand (18%, 8/44) participated in the study day. The majority of the sites were public hospitals, with private hospitals representing just 11% (5/44) of participating ICUs.
Data from 629 patients (Table 1) were collected as part of the Point Prevalence Program, with two patients excluded from our analysis due to lack of data in the delirium domain.
Delirium assessment
On the study day, 54% (336/627) of patients had at least one screening assessment for delirium performed. Of these 336 patients, 32% (109) had an assessment for delirium conducted once, 32% (108) of patients were assessed twice, and 35% (118) of patients had an assessment recorded three or more times on the study day. One patient was recorded as having an assessment for delirium conducted but the number of assessments was not provided.
The most frequent tool methodology to identify delirium was the Confusion Assessment Method for the ICU (CAM-ICU), with 88% (296/336) of the screened patients being evaluated using this method. “Clinical opinion” was the most commonly used method after CAM-ICU, with 6% (20/336) of patients assessed using this method. “Other” assessment was recorded for 5% (16/336) of patients. Four patients who had a delirium assessment had no response recorded as to the assessment method used. The Intensive Care Delirium Screening Checklist was not used to complete any assessments.
Of the patients who had at least one delirium assessment performed on the study day, delirium was present in 20% (68/336), representing 11% of all patients from the study day. For most patients diagnosed as delirious, the type of delirium was not specified, but when specified, hyperactive delirium was the most frequent manifestation recorded (Table 2).
Of the patients who had at least one delirium assessment performed on the study day, delirium was present in 20% (68/336), representing 11% of all patients from the study day. For most patients diagnosed as delirious, the type of delirium was not specified, but when specified, hyperactive delirium was the most frequent manifestation recorded (Table 2).
Sedation assessment
During the study day, depth of sedation was quantified at least once in 89% (556/627) of patients. Depth of sedation was categorised using the RASS for 80% (500/627), the Riker Sedation Agitation Scale for 8% (50/627), the Ramsay Sedation Scale and “sedation assessed by other methods” for less than 1% each (4/627 and 2/627 respectively).
When limiting data to those patients who had the RASS performed, about one-quarter were at least deeply sedated or unarousable at one time point (Table 3). Forty-nine patients had a highest RASS score of -4 or less, with none of these patients having a CAM-ICU assessment performed.
Drug administration
During the study day, 18% (111/627) of patients were administered at least one drug commonly prescribed to treat delirium, with 23% (25/111) of these patients receiving more than one of the listed drugs. Of the 111 patients who received at least one of these drugs, 41% (46) did not have any assessment for delirium recorded on the study day.
Of the drugs used to treat delirium, quetiapine was the most frequently administered (Table 4) and 12% (74/627) of all patients on the study day received an antipsychotic drug. On review of these 74 patients who received at least one antipsychotic drug, 36% (27) did not have any assessment for delirium recorded on the study day.
For the patients deemed to have hyperactive or mixed hyperactive/hypoactive delirium, 85% (17/20) received a listed antipsychotic or α-2 agonist drug. For patients deemed to have hypoactive delirium, 30% (3/10) received a listed drug.
Physical restraints
Data on the presence of a physical restraint were recorded for 626 patients, with 8% (48/626) of patients being restrained at some time point during the study day. Of the patients physically restrained, only 17% (8/48) were diagnosed with delirium, with 31% (15/48) screened as not having delirium and 52% (25/48) having no formal assessment recorded. Of the 8 patients who were physically restrained and diagnosed with delirium, 63% (5/8) were considered to have either hyperactive delirium or a combination of both hyperactive and hypoactive delirium. Of those restrained, 35% (17/48) also had a drug administered likely to have been used to treat delirium.
Patient outcomes
At day 28, 23% (143/627) of patients had not yet been discharged from ICU or hospital. For those patients who had been discharged, 83% (403/484) of patients were alive at hospital discharge.