Anaesthesia and Stress Response to Surgery
The body reaction to surgery ranges from minor to massive both locally and generally. General response is in the form of widespread endocrinal, metabolic and biochemical reactions throughout the body. Neuro-endocrinal hormone system and inflammation mediators are involved and this process is called "stress response". The response has a compensatory mechanism and provides a maximum chance of survival because of increased cardio-vascular functions, fluid preservation and supply of increased demands for energy generating substrates. If the stress response is prolonged, it may result in exhaustion of essential components of the body, fatigue, decreased resistance, delayed ambulation and increased morbidity and mortality. Suppression of immune defense mechanisms has been demonstrated in the postoperative period. Such immune compromise can affect the postoperative infection rate, healing process, and the rate and size of tumour metastases disseminated during surgery. The mechanism of immunosuppression in the postoperative period is not fully understood. The known mediators of immune depression are neuroendocrine response as well as intravenous opioids and inhalational agents, which have shown to increase the susceptibility to infection through a significant cautions in choosing anaesthetic agents, to minimise harm to the patients. In this paper we review the data about the influence of different anaesthetic agents on neuroendocrine, immune and inflammatory response to surgical stress.