|Year : 2020 | Volume
| Issue : 2 | Page : 113-117
Incidence, prevalence, risk factors and outcome of delirium in the intensive care unit of a tertiary care hospital
Samta Goyal1, Anupam Shrivastva1, Gurpreet Singh1, Sandeep Kumar Goyal2, Deepshikha Kamra3, Sandeep Kaur1, Maninder Kaur1, Lovepreet Kaur1
1 Department of Critical Care, SPS Hospitals, Ludhiana, Punjab, India
2 Department of Psychiatry and Behavioural Sciences, SPS Hospitals, Ludhiana, Punjab, India
3 Department of Community Medicine, CMCH, Ludhiana, Punjab, India
|Date of Submission||05-Jun-2020|
|Date of Decision||14-Jun-2020|
|Date of Acceptance||29-Aug-2020|
|Date of Web Publication||23-Feb-2021|
Sandeep Kumar Goyal
Department of Psychiatry and Behavioural Sciences, SPS Hospitals, Ludhiana, Punjab
Source of Support: None, Conflict of Interest: None
Context: Delirium is an acute fluctuating disorder. Impairment in attention and awareness is considered a core symptom. Data from the west suggests that up to 80% of ventilated patients have delirium. Aims: The aim of this study was to evaluate the incidence, prevalence, risk factors, and outcome of delirium in the intensive care unit (ICU) of a tertiary care hospital. Settings and Design: The study was carried out in various ICUs of a multidisciplinary tertiary care hospital after approval from the Institutional Ethics Committee. Written informed consent was obtained from the patients or family members of the patients before enrolling in the study. Subjects and Methods: Consecutive patients aged 16 years or more admitted to the ICUs were recruited for the study. Patients with bilateral deafness and blindness, neurosurgical and neurological cases, and patients or relatives refusing consent were excluded. All the patients were assessed between 9 am and 5 pm daily on the Richmond Agitation and Sedation Scale (RASS) to assess the level of sedation and agitation. The patients found to be arousable (−3 to + 4) were screened using the Confusion Assessment Method for ICU (CAM-ICU) for the presence of delirium. Those patients who screened positive for delirium on CAM-ICU were further assessed by the psychiatrist for the diagnosis of delirium as per the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision ( DSM-IV-TR) diagnostic criteria. All the enrolled patients were administered an etiological checklist specifically designed for the study. The patients were followed until the point of discharge from ICU or death. Statistical Analysis Used: Data analysis was performed using Epidata Analysis version 2.2.2 and Epilnfo 3.5.4 software. Results: Out of 109 patients, 18 (16.5%) patients had delirium within 24 h of admission in ICU, and 36 (33%) developed delirium after 24 h of ICU stay. Conclusions: Thus a total of 49.5% of patients developed delirium during ICU stay. History of delirium in the past, the use of invasive ventilation, and hypocalcemia were significantly more in delirious patients as compared to nondelirious patients. The mean stay of delirious patients in ICU was significantly more. Restraints were used more in delirious patients, and the difference was statistically significant.
Keywords: Delirium, intensive care unit, incidence, outcome, prevalence, risk factors
|How to cite this article:|
Goyal S, Shrivastva A, Singh G, Goyal SK, Kamra D, Kaur S, Kaur M, Kaur L. Incidence, prevalence, risk factors and outcome of delirium in the intensive care unit of a tertiary care hospital. J Mental Health Hum Behav 2020;25:113-7
|How to cite this URL:|
Goyal S, Shrivastva A, Singh G, Goyal SK, Kamra D, Kaur S, Kaur M, Kaur L. Incidence, prevalence, risk factors and outcome of delirium in the intensive care unit of a tertiary care hospital. J Mental Health Hum Behav [serial online] 2020 [cited 2022 May 20];25:113-7. Available from: https://www.jmhhb.org/text.asp?2020/25/2/113/309971
| Introduction|| |
Delirium has an acute onset of symptoms, with a fluctuating course. It is characterized by disturbances in attention, memory, orientation, comprehension, disturbances in the sleep-wake cycle, speech and language disturbances, affective lability, perceptual abnormalities (hallucinations, illusions, etc.), and delusions. Based on the psychomotor activity, delirium is subtyped as hyperactive, hypoactive, and mixed.
Admission to ICU, indwelling catheter, malnutrition, treatment with more than three medications, prolonged sleep deprivation, and use of physical restraints are precipitating factors whereas male gender, age more than 65, visual and hearing impairment, dementia, comorbid renal or hepatic disease are predisposing factors for delirium. Sepsis, urinary tract infection, pneumonia, metabolic disturbances, nutritional deficiencies, substance withdrawal, and treatment with anticholinergic medications are common etiological factors.
Incidence of delirium in ICU has wide variation ranging from 11% to 87%,, whereas prevalence ranges from 32.3% to 77%., However, delirium goes undetected in 75% of the cases in the absence of the use of a structured diagnostic instrument.
Delirium is known to be associated with varied negative outcomes like a prolonged hospital stay, need for institutional care, poor functionality, and high treatment costs.
The presence of delirium increases the ICU stay and due to this, the ICU facilities are consumed by these patients for a long duration and resultantly, many other needy patients suffer too. Hence, it was thought that the timely identification of delirium can lead to the early treatment of these subjects and reduction in ICU stay and appropriate use of existing infrastructure and workforce. The first step in this direction was to understand the incidence, prevalence, risk factors, and outcome of delirium in ICU. Previously, routine screening for delirium was not done and the psychiatrist used to be called only if the primary consultant or ICU consultant felt that the patient was delirious. Understanding the incidence, prevalence, risk factors, and outcome can sensitize the clinicians attending these subjects and lead to early and proper identification, adequate treatment, and reduction in overall ICU stay. The current study was an attempt in the same direction.
| Subjects and Methods|| |
The study aimed to evaluate the incidence, prevalence, risk factors, and outcome of delirium in the intensive care unit (ICU) of a tertiary care hospital.
This was a prospective study done at the ICU of a multidisciplinary tertiary care hospital which has various medical and surgical specialties. The ICU in which this study was done is managed by the Department of critical care. This 23-bedded facility provides ICU care to patients from the medical and surgical departments. A patient admitted to the ICU is cared for by the critical care specialists in liaison with the primary treating team. On stabilization of clinical status, the patient is shifted out of the ICU, and care is provided by the primary treating team alone. Approval from the Institutional Ethics Committee was taken.
Consecutive patients admitted to the medical ICU from October 15 to December 15, 2018 were recruited for the study. Written informed consent was obtained from the family members of the patients before enrolling in the study.
- Bilateral deafness and blindness
- Neurosurgical and neurological cases
- Patient and relatives refusing consent.
All the eligible patients were assessed between 9 am and 5 pm daily on Richmond Agitation Sedation Scale (RASS) to assess the level of sedation and agitation. Those patients who were arousable (−3 through 4) on RASS were evaluated on confusion assessment method for ICU (CAM-ICU) to screen for delirium. If a patient was not having delirium on a particular day or was not assessable, he was again evaluated on RASS on a subsequent day and if found assessable further evaluations were carried out.
Those patients who screened positive for delirium on CAM-ICU were further assessed by the psychiatrist for the diagnosis of delirium as per the diagnostic and statistical manual of mental disorders, 4th edition, text revision (TR) diagnostic criteria. All the enrolled patients were administered an etiological checklist specifically designed for the study, acute physiology and chronic health evaluation II (APACHE-II), and sequential organ failure assessment (SOFA) score. All the variables included in the etiological checklist were rated as “present” or “absent” based on the history, investigation reports, and continuous monitoring of patients.
The patients were followed until the point of discharge from ICU or death. The patient was managed appropriately, as advised by the psychiatrist involved in the study.
Richmond agitation and sedation scale
It is a 10-point scale with four levels to assess the anxiety or agitation (+1 to + 4), one level to denote a calm and alert state (0), and five levels to assess the level of sedation (−1 to − 5). A score of − 4 indicates that the patient is unresponsive to verbal stimulation and finally, culminating in unarousable states (−5). It has good inter-rater reliability and validity.
Confusion assessment method for intensive care unit
It can be used in patient arousable to voice without the need for physical stimulation. It has a minimum of 93% sensitivity and 89% specificity for detecting delirium in comparison to the full Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) assessment. When administered by a trained health-care professional, the CAM-ICU takes only 1–2 min.
DSM-IV-TR Criteria for Delirium:
DSM-IVTR criteria for delirium are considered to be standard criteria for making the diagnosis of delirium APACHE-II score:
APACHE II is a measure of severity of disease for adult patients admitted to ICUs. Only one score is calculated based on the physiological parameters in admission and no new score can be determined during the hospital stay. However, a new score can be assigned if the patient is readmitted.
SOFA, developed by the European Society of Critical Care Medicine, is a scoring system to determine the extent of a person's organ function or rate of failure. It is used to assess organ dysfunction or failure over time and is useful in the evaluation of morbidity. The sequential assessment of organ dysfunction during the first few days of ICU admission is considered to be a good indicator of prognosis. Independent of the initial score, an increase in SOFA score during the first 48 h in the ICU predicts a mortality rate of at least 50%.
Data were entered using classical EpiData entry software. Data analysis was performed using Epidata Analysis version 2.2.2 and Epilnfo 3.5.4 software. Data were analyzed using the mean, standard deviation, frequency, and percentages. Comparisons were made using the Chi-square test.
| Results|| |
During the study period, 109 patients were enrolled in the study. The mean age of the study sample was 33.00 years (range 16–91 years). The sample comprised 65 males (59.6%) and 44 females (40.4%).
The mean of APACHE score of the whole sample was 14.72 (standard deviation [SD] = 6.59; range-6–35) and that of the SOFA score was 6.79 (SD = 2.88; range 1–18).
Out of 109 patients, 18 (16.5%) patients had delirium at the first assessment (i.e., within 24 h of admission in ICU) and were classified as “prevalence cases” of delirium. Of the 91 patients who were nondelirious at first assessment, 36 (33%) developed delirium after 24 h of ICU stay and were considered as “incidence cases” of delirium. Thus a total of 49.5% of patients developed delirium during ICU stay [Table 1].
The prevalence cases accounted for 33.3% of all delirium cases and incidence cases accounted for 66.7% of all delirium cases.
Risk factors and delirium
History of delirium in the past, the use of invasive ventilation, and hypocalcemia were significantly more in delirious patients as compared to nondelirious patients. The mean stay of delirious patients in ICU was significantly more. Restraints were used more in delirious patients and the difference was statistically significant [Table 2].
|Table 2: Comparison of risk factors between delirious and nondelirious patients|
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Outcome of delirium
All the study participants were followed up until they were discharged from the hospital or their death. Of the patients who developed delirium (n = 54), six patients (11.1%) died during their hospital stay, this was in contrast to 4 patients (7.3%) in the nondelirium group (n = 55) and the difference was statistically not significant (Chi-square test value-2.288; P = 0.3186) [Table 3].
|Table 3: Comparison of outcome of delirium between delirious and nondelirious patients|
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| Discussion|| |
Incidence and prevalence of delirium
Out of 109 patients, 18 (16.5%) patients were “prevalence cases”, while 36 (33%) were the “incidence cases” of delirium. Thus a total of 49.5% of patients developed delirium during ICU stay.
Studies from the developed countries, which have evaluated the prevalence of delirium in ICU patients, have reported a range of 20%–80%. The prevalence figures vary between 20%–50% in patients with physical illnesses of lower severity and 50%–80% in severely ill mechanically ventilated patients during ICU stay.
Koster et al. reported that the incidence of delirium after cardiac surgery was 17.3%,in comparison to 33% in our study, and the difference can be due to the different profiles of the patients.
A previous study which evaluated 151 patients admitted to the Respiratory ICU of PGI Chandigarh, reported an incidence rate of delirium 24.4% and prevalence rate of delirium 53.6% respectively, thus total 78% of the patients had delirium which is more as compared to our study (49.5%). The difference possibly could be due to differences in the severity of illness in both studies, which is reflected by the fact that the mean APACHE-II score of patients who developed delirium in the previous study was 19.52 in contrast to 15.76 in the present study. Similarly, the mean APACHE-II score of nondelirium patients in the patient was also lower in the present study compared to that reported by Sharma et al.
In another study by Grover et al. 68% of patients developed delirium during their ICU stay as compared to 49.5% in the present study, and the difference can be due to different profiles of the patients.
Risk factors for delirium
Predictors of delirium in the present study are a history of delirium in the past, the use of invasive ventilation, and hypocalcemia. The mean stay of delirious patients in ICU was significantly more. Restraints were used more in delirious patients and the difference was statistically significant.
Earlier studies have reported infections, hypertension, hypocalcemia, hyponatremia, and use of steroids, etc., with the development of delirium in ICU patients;,,, however, only hypocalcemia out of these variables emerged as important predictors of delirium in the present study. These differences possibly reflect the differences in various types of ICU setups studied (medical versus surgical) and patient selection practices.
The outcome of subjects with delirium
The mean duration of stay of patients who developed delirium was 8.43 days and those who did not develop delirium was 4.27 days and this difference between the two groups was statistically significant (P = 0.0008). The present study supports the findings from other studies that delirium is associated with a longer duration of ICU stay.,
In the present study, 11% of patients with delirium died during their ICU/hospital stay; this was in contrast to 7.3% patients in the nondelirium group and the difference between the two groups was not statistically significant whereas in the study by Sharma et al. no patient died in the nondelirious group as compared to 30.7% deaths in delirium group. As discussed earlier the difference possibly could be due to differences in the severity of illness in both studies.
The present study has many limitations like small sample size and a single assessment of delirium per day (from 9 am to 5 pm). Our study was done in an ICU that caters patients from multiple specialties. Furthermore, the present study represents findings from a single center. Hence, the results may not be generalizable to specialty ICU setting or general medico-surgical wards.
To conclude, this prospective study with daily assessment was able to identify cases of delirium in patients admitted to ICU. This study shows that about one-half of patients admitted to ICU develop delirium. Further, this study shows that some of the predictors of delirium can be easily modified. This study also shows that delirium is associated with high mortality although the difference was not statistically significant.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]