Persistent critical illness: baseline characteristics, intensive care course, and cause of death.

OBJECTIVES: Persistent critical illness (PerCI) is associated with high mortality and discharge to institutional care. Little is known about factors involved in its progression, complications and cause of death. We aimed to identify such factors and the time when the original illness was no longer the reason for intensive care unit (ICU) stay.

DESIGN: Retrospective matched case-control study using an accepted PerCI definition (> 10 days in ICU).

SETTING: Single-centre tertiary metropolitan ICU.

PARTICIPANTS: All adult patients admitted during a 2-year period were eligible, matched on diagnostic code, gender, age and risk of death.

MAIN RESULTS: Seventy-two patients staying > 10 days (PerCI cases) were matched to 72 control patients. The original illness was no longer a cause for continued ICU stay after a median of 10 days (interquartile range [IQR], 7-16) versus 2 days (IQR, 0-3); P < 0.001. Patients with PerCI were more likely to develop new sepsis (52.8% v 23.6%; P < 0.001), delirium (37.5% v 9.7%; P < 0.001), ICU-acquired weakness (15.3% v 0%, P = 0.001), and to be discharged to chronic care or rehabilitation (37.5% v 16.7%; P < 0.005). Death resulting from sepsis with multi-organ failure occurred in 16.7% v 8.3% of control patients ( P = 0.13), and one-third of patients with PerCI were not mechanically ventilated on Day 10.

CONCLUSION: PerCI likely results from complications acquired after ICU admission and mostly unrelated to the original illness; by Day 10, the original illness does not appear to be its cause, and new sepsis appears an important association.