domingo, agosto 19, 2007

Delirium

Falando um pouco sobre delirium, este é um comentário sobre o artigo publicado na edição de 13 de agosto do Archives of Internal Medicine.

"Older patients admitted to an intensive care unit (ICU) who had dementia, acidemia, or elevated serum creatinine or were receiving benzodiazepines were at high risk of developing delirium within 48 hours, according to a recent study.
The study, led by Margaret A. Pisani, MD, from Yale University School of Medicine, in New Haven, Connecticut, is published in the August 13 issue of the Archives of Internal Medicine.
"Our results include previously identified risk factors for delirium, including dementia and benzodiazepine use, but also identify new factors such as elevated creatinine level and low pH," the group writes, adding that by knowing about these ICU admission risk factors for delirium, clinicians can take prompt action to identify and treat those at greatest risk for delirium.
The group explains that prevalence of delirium, an acute disorder of attention and cognition, is reported to be as high as 78% to 87% among ICU patients, and it is associated with a longer hospital stay and increased morbidity and mortality. To date, only a few studies prospectively looked at risk factors for delirium in the ICU. The team aimed to extend this earlier work, to identify which patient characteristics were most strongly associated with the occurrence of delirium within the first 48 hours of ICU admission.
They performed a prospective study of 304 consecutive patients age 60 years and older who were admitted to a 14-bed ICU in an urban teaching hospital. The patients had a mean age of 75 years, and 47% were men. A total of 214 (70.4%) developed delirium within 48 hours of ICU admission.
Using a multivariate logistic regression model, the researchers identified 4 risk factors for developing delirium within 48 hours of admission to the ICU.
ICU Admission Risk Factors Associated with Delirium Within 48 Hours
Risk factor
Odds ratio (95% CI)
P
Dementia*
6.3 (2.9 – 13.8)
< .001
Receipt of benzodiazepines immediately before ICU admission
3.4 (1.6 – 7.0)
.001
Serum creatinine > 2 mg/dL
2.1 (1.1 – 4.0)
.02
Arterial pH < 7.35
2.1 (1.1 – 3.9)
.02*Informant Questionnaire on Cognitive Decline in the Elderly > 3.3.
Dementia, present in 30.9% of the cohort, was the strongest factor for delirium, which agrees with previous studies. "Despite its importance, dementia is not screened for on ICU admission, and ICU physicians are often unaware of their patient's preexisting dementia," the researchers write. Dr. Pisani told Medscape that although dementia is not a modifiable risk factor, it is important to screen for and identify dementia, so as to then, when possible, avoid using restraints and prescribing anticholinergic drugs, which are factors that are known to contribute to delirium.
"Importantly, at least 3 of the identified risk factors are amenable to intervention," the group writes. Dr. Pisani explained that physicians need to carefully assess a patient's need for benzodiazepines, which might allow for the reduction of the use of these drugs or of their dosages. She added that, in addition, clinicians need to "pay close attention to" and treat underlying causes of acidemia (arterial pH of less than 7.35) and high serum creatinine (a marker of renal dysfunction).
The group concludes that the "high prevalence and significant health impact of these admission risk factors make their identification of critical importance in ICU care," and future clinical trials are needed to assess the effects of intervention strategies.
Arch Intern Med. 2007;167:1629-1634."

Cássia Righy