Background: We have performed a prospective qualitative investigation of the ICU syndrome/delirium; the main parts of which have recently been published. The aim of the present study was to explore the relationship between the ICU syndrome/delirium and age, gender, length of ventilator treatment, length of stay and severity of disease, as well as factors related to arterial oxygenation and the amount of drugs used for sedation/analgesia.
Methods: Nineteen mechanically ventilated patients who had stayed in the ICU for more than 36 h were closely observed during their stay, and interviewed in depth twice after discharge. Demographic, administrative and medical data were collected as a part of the observation study.
Results: Patients with severe delirium had significantly lower hemoglobin concentrations than those with moderate or no delirium (P=0.033). Patients suffering from severe delirium spent significantly longer time on the ventilator and at the ICU, and were treated with significantly higher daily doses of both fentanyl (P=0.011) and midazolam (P=0.011) in comparison with those reporting only moderate or no symptoms of delirium. There were no significant differences in the Therapeutic Intervention Scoring System scores, reflecting the degree of illness, between patients with and without delirium.
Conclusion: The development of the ICU syndrome/delirium seems to be associated with decreased hemoglobin concentrations and extended times on the ventilator. Prolonged ICU stays and treatment with higher doses of sedatives and opioids in patients with delirium appear to be secondary phenomena rather than causes.