Delirium in the Intensive Care Unit: Incidence, risk factors, and impact on outcome

IntRoductIonDelirium is a disturbance of consciousness, cognition, attention, and perception.These symptoms usually have an acute onset and a transient fluctuation along the day.[1] Hyperactive delirium which is a state of great agitation has often been described as the most common subtype observed in clinical practice and can Wbe misdiagnosed as psychotic disorder or an agitated dementia.Hypoactive delirium occurs frequently but has a bad prognosis because of lack of recognition by clinicians.[2] Previous studies reported an incidence of delirium in Intensive Care Unit (ICU) between 11% and 87%.[3,4] The risk of delirium is particularly high in elderly people, those with preexisting cognitive impairments, [5,6] terminal illnesses, [7] patients undergoing major surgery, [8] and those who are admitted to an ICU.[10][11][12] Comorbidities, severity of illness, drugs and tobacco withdrawal, ICU conditions, and several treatments are common risk factors for delirium in ICU.[5,[9][10][11][12] Delirium can result in bad outcome including prolonged mechanical ventilation, longer ICU and hospital length of stay (LOS), higher mortality, long-term cognitive impairment, [13][14][15] and higher cost of care.[16] We believe that incidence and risk factors for delirium may be different in a Tunisian ICU given the type of patients less frequently alcoholic because of religious beliefs; additionally, COPD, known as a risk factor for delirium, represents >30% of admissions in our unit.Our practices may also be different from those observed in other ICUs since we do not use a protocol of sedation and we do not allow visits in the patient's bedside.Background: The incidence and risk factors for delirium vary among studies.Objective: We aimed to determine the incidence, risk factors, and impact on outcome of delirium in a medical Intensive Care Unit (ICU) in Tunisia using a prospective observational study.Patients: All consecutive patients admitted to the ICU between May 2012 and April 2013 were included if they were aged more than 18 years and had an ICU stay of more than 24 h.Patients who had a cardiac arrest or have a history of dementia or psychosis were excluded.Patients eligible for the study were evaluated by the medical staff to detect delirium using the CAM-ICU.Results: A total of 206 patients were included, 167 did not present delirium and 39 (19%) were analyzed for delirium.Delirious patients had a significantly longer duration of mechanical ventilation (10 days[6-20] vs. 2 days[0-7]) respectively and length of stay in ICU (21.5 days [10.5-32.5] vs. 8 days [5-13]), with no impact on mortality.Delirium was associated with high incidence of unintentional removal of catheters (39% vs. 9%; P < 0.0001), endotracheal tubes (18% vs. 1%; P < 0.0001), and urinary catheters (28% vs. 2%, P < 0.0001).In multivariable risk regression analysis, age (odds ratio [OR] = 4.1, 95% confidence interval [CI]: 1.39-12.21;P = 0.01), hypertension (OR = 3.3, 95% CI: 1.31-8.13;P = 0.011), COPD (OR = 3.5, 95% CI: 1.47-8.59;P = 0.005), steroids (OR = 2.8, 95% CI: 1.05-7.28;P = 0.038), and sedation (OR = 5.4, 95% CI: 2.08-13.9;P < 0.0001) were independent risk factors for delirium.We did not find a relationship between delirium and mortality.Conclusion: Delirium is frequent in the ICU and is associated with poor outcome.Several risk factors for delirium are linked to intensive care environment.