Assessment of incidence and risk factors for intensive care acquired delirium in mechanically ventilated patients in surgical intensive care unit – National Hospital of Sri Lanka

Background: Delirium is a common, preventable complication of intensive care unit treatment. It is often under-diagnosed and is an independent predictor of mortality and morbidity. Delirium screening is not a routine practice currently at surgical ICU-NHSL.

Methodology: Patients requiring mechanical ventilation for more than 24 hours at surgical ICU- NHSL were screened for delirium using CAM–ICU score. The potential risk factors contributing to delirium were also studied. Data was analysed using SPSS 17.

Results: Delirium was present in 66.6% patients. Importantly, the commonest subtype was hypoactive delirium (50%) while hyperactive and mixed delirium accounted for 30% and 20% respectively. Significantly higher proportion of patients who developed delirium were males (p= 0.02). There was no association between patients’ age and development of delirium.  Patients with delirium had a significantly higher incidence of acute liver impairment (p=0.03), acute malnutrition (p=0.05) and impaired glycaemic control (p= 0.05). There was a statistically significant association between presence of invasive lines (p=0.004), use of propofol (p= 0.006) and use of opioids (0.03) and development of delirium.

Conclusion: The study revealed high incidence of delirium in patients who are mechanically ventilated for more than 24 hours. Majority of them were having hypoactive delirium. The need for early identification using routine delirium screening tools and assessment of risk factors contributing to delirium is highlighted.