Perioperative Care; Fluid and Electrolyte

Nausea and Vomiting

Post-operative nausea and vomiting (PONV) may cause an unplanned hospital admission. The risk factors are multifactorial Strategies to prevent PONV include considering regional anaesthesia, reducing the use of opioids, adequate hydration and a combination of anti-emetic drugs. Classes of anti-emetics include anti-histamines (cyclizine), 5HT3 antagonists (ondansetron), anticholinergics (hyoscine hydrobromide), steroids (dexamethasone) and D2 antagonists (metoclopramide). They act on receptors that have sensory afferents to either the vomiting centre (in the medulla) or the chemoreceptor trigger zone outside the blood brain barrier.