Causes of death in intensive care patients with a low APACHE II score

Background: Little is known about the actual causes of death of patients with a low APACHE II score, but iatrogenic reasons may play a role. The aim of this study was to evaluate the demographics, course of disease, and causes of death in this specific group of ICU patients. Methods: For this retrospective observational study, adult patients (>18 years) admitted to the ICU were included. Results: During the 47-month study period, 9279 patients were admitted to our ICU, of which 3753 patients had an APACHE II score <= 15. Of the latter group of patients, 131 (3.5%) died during their hospital stay. Their median (IQR) APACHE II was 12 (11-14) and their main reason for ICU admission was respiratory insufficiency (47%). Both in patients with and without limited therapy, haemodynamic insufficiency was the main cause of death (50 and 69%, respectively). Three patients died directly related to medical interventions. Conclusion: Most patients with an APACHE II score lower than 15 who died were admitted to the ICU because of respiratory insufficiency. The main cause of death was haemodynamic insufficiency following limited therapy because of an unfavourable prognosis. In less than one out of 1000 cases of this low-risk group of patients death was related to iatrogenic injury.