Significant cognitive dysfunction in non-delirious patients identified during and persisting following critical illness

Recent studies have shown significant cognitive problems some months after critical illness. However there has been no research examining cognitive function within the intensive care unit (ICU) in non-delirious patients. A prospective study in an ICU. Using the Cambridge Neuropsychological Test Automated Battery (CANTAB), 30 long-stay, tracheal-intubated ICU patients were tested. Prior to testing on ICU the Confusion Assessment Measure (CAM-ICU) was administered and only those patients clearly not delirious and off sedation for several days were tested. The CANTAB tests were repeated a week after ICU discharge on the general ward and then again at 2 months. Sixteen patients completed the follow-up. While on ICU all 30 patients showed significant problems with strategic thinking and problem solving; 20 patients had some problems with memory. The degree of difficulty with problem solving on ICU was correlated with length of ICU stay (p=0.011), age (p=0.036) and length of hospital stay post ICU (p=0.044). Problems with memory in ICU and on the general ward were correlated with admission APACHE II score (p=0.004 and p=0.005 respectively). At the 2-month follow-up 5 of 16 patients (31%) scored below the 25 percentile for memory and 8 of 16 (50%) below the 25 percentile for problem solving (Slater TA, Jones C, Griffiths RD, Wilson S, Benjamin K (2004) Cognitive impairment during and after intensive care: a pilot study. Intensive Care Med 30 [Suppl 1]:S199). Difficulties with problem solving and poor memory remained a significant issue for 2 months after ICU discharge.