Single Dose Dexamethasone for Postoperative Nausea and Vomiting--a Matched Case-Control Study of Postoperative Infection Risk (Report‪)‬

Postoperative nausea and vomiting (PONV) remains a major challenge to the specialty of anaesthesia. The associated morbidity and healthcare costs are enormous (1). Fifty percent of surgery is now performed on a day-case basis. Nausea is the most important factor determining length of stay after ambulatory surgery (2) and the most common cause of unplanned hospital admission (3). Patients fear PONV more than they fear postoperative pain [4] and it adversely affects patients' satisfaction (5). A clear cut scoring system to determine risk of PONV has been described (6). Despite this, PONV occurs in 30% of post-surgical patients overall and up to 70% of high-risk patients (7,8). Hence, consensus guidelines have been published and recently updated (7,9). Dexamethasone is an anti-emetic that is used as a single dose prophylactically during surgery in patients at high risk of developing PONV10 and is more effective as prophylaxis, particularly against late PONV, rather than as a therapy once PONV is established (10). It is also, however, a glucocorticoid and, in common with other glucocorticoids, has potent immunosuppressive actions. The primary focus of research into these agents concentrates on mechanisms of immunosuppression rather than questioning its existence (11,12). Some studies have examined outcomes but they were not powered to detect a complication of low incidence such as infection (4,13). The impact of postoperative infections on long-term outcomes is becoming better appreciated with the publication of large population studies (15). The effect is not innocuous (16). In order to address this question, we designed a matched case-control study to specifically examine the association between dexamethasone administration and the occurrence of postoperative infection.