Postoperative nausea and vomiting. 1: Physiology and aetiology

There is a vast amount of research available relating to postoperative nausea and vomiting (PONV). This research has been analyzed and summarized in a series of two articles which draw out the main factors influencing the incidence and affecting the treatment of the condition. This, the first article, will describe the physiological processes that result in PONV. An analysis will then follow of the many factors that contribute to the complex multifactorial aetiology of PONV. These factors include personal, preoperative, intraoperative and postoperative variables which affect differing neurotransmitter centres in the chemoreceptor trigger zone (CTZ) which is situated in the brainstem. These variables will then be related to the appropriate neurotransmitter centre allowing a greater understanding of the most likely physiological pathways involved in specific cases of PONV. The second article will explore the management and treatment of PONV.