The Immunological Side-Effects of Sedative Agents in the Intensive Care Unit

The immune system is a sophisticated and complex system that is influenced by various exogenous insults such as surgical stress and endogenous factors like the sympathetic nervous system. It has been demonstrated that sedative agents used in clinical practice alter the balance of pro- and anti-inflammatory cytokines. These effects may be reversible following short exposure to anaesthetic agents and sedative drugs. However, many critically ill patients are sedated for prolonged periods of time, which raises concerns about the risks of immunological interference by sedative agents. When one considers that sepsis accounts for significant morbidity in intensive care, it is imperative that anything modifiable which causes immunosuppression is identified. The systemic inflammatory response syndrome is known to feature an increase in pro-inflammatory mediators, something which could be influenced by sedative agents. We propose to outline the details surrounding this area, focusing on sedative agents commonly used in the intensive care setting. A more detailed understanding of this area could lead to improved patient outcomes and have far-reaching influence on clinical practice in critical care.