A growing number of very sick and hospital-dependent patients in an ageing population, together with a chronic lack of intensive care beds, has resulted in a significant impairment in hospital care. Acute, life-threatening symptoms are frequently missed, leading to increased mortality and morbidity. Many projects have been introduced to improve the situation; among them, the creation of early warning scoring and trigger systems, and organisation of in-hospital medical response and critical care teams. The aim of this review is to discuss the development and implementation of such systems in different countries. Organisational aspects as well as the main differences between medical emergency teams and intensive care outreach services, are presented. During the development and organisation phase, all plans have to be assessed against specific local needs and requirements. The effects of the introduction of outreach systems and medical emergency teams on hospital morbidity, mortality and treatment outcome, are briefly analyzed.