Introduction

With advances in surgical and anaesthetic practice, the majority of patients undergoing cardiac surgery spend less than 24 hours in critical care. However, a proportion (between 4.8% and 16%) are admitted for longer than 5 days. This is more likely in the increasingly prevalent older patient population, who often have comorbidities. In addition, the development of less invasive surgery has permitted higher risk patients to be accepted for surgery.

For patients with a complicated critical care stay, surgical mortality in terms of 30-day or in-hospital mortality only partially reflects the overall outcome. Longer term mortality and morbidity provide a better analysis of the benefit of surgery.

Mortality

In the mid 1990s, authors began to examine the long-term mortality of cardiac surgical patients requiring prolonged critical care treatment. A number of studies have been published. In these studies, long-stay patients represented around 5% of those who underwent cardiac surgery, but accounted for 50% of the hospital critical care days and consumed 48% of the total critical care resources and 23% of the hospital direct costs. Early mortality (within 10 days) appears related to the patient risk profile and to the type of operation performed. A late increase in mortality is noted for those patients remaining in critical care, which is due to complications such as ventilator-associated pneumonia and sepsis.