Validity and reliability of the DDS for severity of delirium in the ICU.
BACKGROUND
Until now, there has been no gold standard for monitoring delirium in intensive care unit (ICU) patients. In this prospective cohort study, a new score, the Delirium Detection Score (DDS), for severity of delirium in the ICU was evaluated.


METHODS
After ethical approval and written informed consent, intensive care doctors and nurses assessed 1073 consecutive patients in surgical ICUs using the DDS together with the Ramsay Sedation Scale (RSS). The DDS is composed of eight criteria (orientation, hallucination, agitation, anxiety, seizures, tremor, paroxysmal sweating, and altered sleep- wake rhythm). Additionally, intensive care doctors had to document the Sedation-Agitation Scale (SAS) combined with a defined clinical assessment. For interrater reliability, pair of evaluators assessed patients in a blinded fashion at the same time.


RESULTS
RSS1 (9%) was associated with a significantly (p < 0.001) higher DDS than RSS levels 2-6. The DDS increased with the severity of delirium (p < 0.001). The receiver operating characteristics (ROC) for the differentiation between no delirium (SAS < 4) and symptoms of delirium at all (SAS 5-7) showed an area under the curve (AUC) of 0.802 (95% confidential interval (CI): 0.719-0.898; p < 0.001) and 69% sensitivity and 75% specificity was determined. For reliability, a Cronbach's alpha of 0.667 was calculated. The paired comparisons revealed an intraclass correlation between 0.642 and 0.758.


CONCLUSIONS
The DDS demonstrated good validity with excellent sensitivity and specificity for delirium. The severity of delirium can be more accurately estimated by the DDS. By its composition of several items, the DDS might help to start a symptom-guided therapy immediately.
Otter
Hilke
H
Department of Anesthesiology, Charité-Universitary Medicine Berlin, Campus Mitte, Germany.
Martin
Jörg
J
Bäsell
Katrin
K
von Heymann
Christian
C
Hein
Ortrud Vargas
OV
Böllert
Patricia
P
Jänsch
Pattariya
P
Behnisch
Ina
I
Wernecke
Klaus-Dieter
KD
Konertz
Wolfgang
W
Loening
Stefan
S
Blohmer
Jens-Uwe
JU
Spies
Claudia
C
D000368:Aged; D016638:Critical Illness / Q000523:psychology / Q000628:therapy; D003693:Delirium / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome