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Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU)
Ely EW, Inouye SK, Bernard GR, Gordon S, Francis J, May L, Truman B, Speroff T et al.. JAMA, 2001-12-01
Topic: Risk, prevention and care in population studies
Context Delirium is a common problem in the intensive care unit (ICU). Accurate diagnosis is limited by the difficulty of communicating with mechanically ventilated patients and by lack of a validated delirium instrument for use in the ICU. Objectives To validate a delirium assessment instrument that uses standardized nonverbal assessments for mechanically ventilated patients and to determine the occurrence rate of delirium in such patients. Design and setting Prospective cohort study testing the Confusion Assessment Method for ICU Patients (CAM-ICU) in the adult medical and coronary ICUs of a US university-based medical center. Participants A total of 111 consecutive patients who were mechanically ventilated were enrolled from February 1, 2000, to July 15, 2000, of whom 96 (86.5%) were evaluable for the development of delirium and 15 (13.5%) were excluded because they remained comatose throughout the investigation. Main outcome measures Occurrence rate of delirium and sensitivity, specificity, and interrater reliability of delirium assessments using the CAM-ICU, made daily by 2 critical care study nurses, compared with assessments by delirium experts using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria. Results A total of 471 daily paired evaluations were completed. Compared with the reference standard for diagnosing delirium, 2 study nurses using the CAM-ICU had sensitivities of 100% and 93%, specificities of 98% and 100%, and high interrater reliability (kappa = 0.96; 95% confidence interval, 0.92-0.99). Interrater reliability measures across subgroup comparisons showed kappa values of 0.92 for those aged 65 years or older, 0.99 for those with suspected dementia, or 0.94 for those with Acute Physiology and Chronic Health Evaluation II scores at or above the median value of 23 (all P Conclusions Delirium, a complication not currently monitored in the ICU setting, is extremely common in mechanically ventilated patients. The CAM-ICU appears to be rapid, valid, and reliable for diagnosing delirium in the ICU setting and may be a useful instrument for both clinical and research purposes.
Key findings
- Main outcome measures Occurrence rate of delirium and sensitivity, specificity, and interrater reliability of delirium assessments using the CAM-ICU, made daily by 2 critical care study nurses, compared with assessments by delirium experts using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria.
- Results A total of 471 daily paired evaluations were completed.
- Compared with the reference standard for diagnosing delirium, 2 study nurses using the CAM-ICU had sensitivities of 100% and 93%, specificities of 98% and 100%, and high interrater reliability (kappa = 0.96; 95% confidence interval, 0.92-0.99).
Why it matters
This study validated the Confusion Assessment Method for the ICU (CAM-ICU) for detecting delirium in mechanically ventilated patients, finding high sensitivity and specificity compared with delirium experts using DSM-IV criteria. It concerns delirium assessment in intensive care, not the treatment, cure, or prevention of Alzheimer's disease.
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Study details
- Study designcohort study
- Participants111
- Effect size86.5%; 13.5%; or 0.94
- Evidence strengthModerate
How this study scored 72/100
Published in a top-tier journal, and it is a cohort study following people over time. Scored zero for randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 10 / 10 | Tier 1 — top-tier general journal (JAMA) |
| Journal's citation record | 4 / 4 | JAMA: journal h-index 1,011 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A cohort study following people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2001 — older than 20 years, still counted |
| Sample size | 2 / 4 | 111 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 7 / 7 | Cited 3,205 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 118.7 citations a year over 27 year(s) since 2001 |
| Impact for its field and year | 4 / 6 | Cited 17.4× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 24 other studies in this library |
| Still being cited | 4 / 4 | Cited 614 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Robert S. Dittus: h-index 85 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Vanderbilt University: institution h-index 1,199 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 11730446) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 72 / 100 | — |
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Read the original
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Ely, E. W., Inouye, S. K., Bernard, G. R., Gordon, S., Francis, J., May, L., et al. (2001). Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU). JAMA. https://doi.org/10.1001/jama.286.21.2703
Vancouver
Ely EW, Inouye SK, Bernard GR, Gordon S, Francis J, May L, et al. Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU). JAMA. 2001. doi:10.1001/jama.286.21.2703. PMID: 11730446.
BibTeX
@article{ely2001-11730446,
author = {Ely, E. W. and Inouye, S. K. and Bernard, G. R. and Gordon, S. and Francis, J. and May, L. and Truman, B. and Speroff, T. and others},
title = {{Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU)}},
journal = {JAMA},
year = {2001},
doi = {10.1001/jama.286.21.2703},
pmid = {11730446},
url = {https://doi.org/10.1001/jama.286.21.2703}
}
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