Risk factors for intensive care delirium

Introduction

Delirium is a common complication in the ICU. The attention of researchers has shifted from the treatment to the prevention of the syndrome, necessitating the study of associated risk factors.

Methods

In a multicenter study of one university hospital, two community hospitals and one private hospital, newly admitted adult patients were included when reaching a Glasgow coma scale greater than 10. Nurse researchers assessed the patients for delirium using the NEECHAM confusion scale. Risk factors were split into four groups: patient characteristics, chronic pathology, acute illness and environmental factors. Odds ratios were calculated using univariate binary logistic regression.

Results

A total population of 508 patients was screened for delirium. The 36 studied factors showed some variability according to the participating hospitals. The overall delirium incidence was 29%. For patient characteristics, age was not a significant factor. Intensive smoking (OR = 2.04) and living singly at home (OR = 1.94), however, contributed to the development of delirium. In the group of chronic pathology, a pre-existing cognitive impairment seemed important as a risk factor (OR = 2.41). In the group of factors related to acute illness, the use of drains, tubes and catheters, acute illness scores, the use of psychoactive medication, a complete sedation or coma and a preceding period of mechanical ventilation showed significant ORs ranging from 1.04 to 13.66. Environmental risk factors were noise, induced by a high number of alarms (OR = 5.37), isolation (OR = 3.81), the absence of visit (OR = 2.83), the absence of visible daylight (OR = 1.80), a bed in a shared ICU room (OR = 1.70), a transfer from another ward or hospital (OR = 3.01) and admittance through the emergency room (OR = 2.19).

Conclusion

The present multicenter study indicated four groups of risk factors for delirium in the ICU. Particularly among those related to the acute illness and the environment, several factors are suitable for preventive action.