Aim: To examine the effectiveness and safety of the sedative agents used in the emergency department following the introduction of ketamine as an agent for procedural sedation Methods: A 2-year prospective audit of sedation practice was undertaken. This specifically examined the rationale behind a doctor's choice of sedative agent, the depth of sedation achieved, adverse events and the time taken to regain full orientation. Results: 210 patients were included of whom 85 (40%) were given ketamine, 107 (51%) midazolam and 18 (9%) propofol. The median time to full orientation was 25 min for ketamine, 30 min for midazolam and 10 min for propofol. Complications occurred in 15.9% of sedations overall (14.6% of those given ketamine, 15.8% given midazolam and 22.2% given propofol). Apnoea and hypoxia most often occurred with midazolam and propofol, while hypertension and hypertonicity were encountered more frequently with ketamine. In addition, 19.5% of patients given ketamine suffered the reemergence phenomenon. The association between deep sedation with no response to pain and adverse events encountered with midazolam does not occur with ketamine. Conclusions: Ketamine is both safe and effective and compares favourably with midazolam as an agent for procedural sedation in the emergency department. Although the re-emergence phenomenon occurred, no psychological sequelae were encountered after return to full orientation. Ketamine may be particularly useful in groups of patients at high risk of adverse effects with midazolam.Ketamine produces a dissociative state and provides good analgesia at a subanaesthetic dosage.

Our results show that almost half of our colleagues would have carried out tube thoracostomy when no pneumothorax was actually present. In a situation where a pneumothorax is a clinical possibility we would recommend either temporarily removing the oxygen mask if clinically stable, or fixing the reservoir bag outwith the field of the CXR by means of adhesive tape to avoid any misinterpretation of this 'mask sign'.