A prospective study of agitation in a medical-surgical ICU: incidence, risk factors, and outcomes

Abstract

Study objectives: Although agitation is thought to be common in the ICU, it has been poorly studied. We evaluated the incidence, risks factors, and outcomes of agitation in ICU.

Design: Prospective observational study.

Interventions: None.

Method: All consecutive ICU admissions over an 8-month period were analyzed.

Measurements and results: Two hundred eleven patients were admitted a total of 216 times during the period of the study. Twenty-nine patients were excluded from the study because their pathology findings did not allow an evaluation of their level of consciousness; 182 patients were actually enrolled. Agitation developed in 95 of 182 patients (52%). Agitation began 4.4 +/- 5.6 days (+/- SD) after admission to the ICU and lasted 3.9 +/- 4.1 days. Patients with agitation had a higher Simplified Acute Physiology Score II on ICU admission than those who did not have agitation (40 +/- 16 vs 33 +/- 13, p < 0.01). By stepwise logistic regression, the independent risks factors for development of agitation included psychoactive drug use at the time of ICU admission (odds ratio, 5.63; 95% confidence interval [CI], 1.32 to 23.70), history of alcohol abuse (odds ratio, 3.32; 95% CI, 1.12 to 10.00), dysnatremia (odds ratio, 4.95; 95% CI, 1.95 to 12.54), fever (odds ratio, 4.52; 95% CI, 1.80 to 11.49), use of sedatives in the ICU (odds ratio, 4.03; 95% CI, 1.62 to 10.40), and sepsis (odds ratio, 2.61; 95% CI, 1.03 to 6.58). Agitation was associated with a prolonged ICU stay (16 +/- 19 days vs 6 +/- 6 days, p = 0.0001), nosocomial infections (34% vs 7%, p < 0.0001), unplanned extubations (17% vs 2%, p = 0.003), and unplanned central venous catheter removal (16% vs 1%, p = 0.001), but not with mortality (12% in the agitation group vs 8% in patients without agitation).

Conclusions: Agitation is a common event in a mixed medical-surgical ICU. It is associated with adverse outcomes including prolonged stay, nosocomial infections, and unplanned extubations. A better knowledge of incidence and risk factors should facilitate identification of patients at risk and decrease the incidence of agitation.