Criteria for intensive care unit admission and the assessment of illness severity

Critical care expansion in the UK has increased in recent years, reflecting increased demand, yet bed occupancy remains high and there are significant difficulties in matching supply and demand. Expansion of ICU services outside the walls of critical care has involved the development of complex multidisciplinary outreach services who exist to support ward teams in caring for individuals who are critically unwell or have recently been stepped down from higher levels of care; there is increased evidence of their effectiveness in reducing mortality and preventing unexpected deterioration. Discharge of patients from critical care is also an area of controversy with conflicting evidence of increased mortality rates for those discharged prematurely or out-of-hours. Careful planning is involved with appropriate post-ICU care is critical to avoiding poor outcomes. ICU scoring systems allow comparison of outcomes between individual units and facilitate research but are unhelpful in predicting outcome for individual patients. Deciding which patients not to admit to ICU are frequently the most difficult decisions facing critical care staff. Many patients previously considered inappropriate for organ support may now be admitted pre-determined limits of treatment or to facilitate complex palliative care needs.