• best evidence topic reports
• oxygen
• stroke
• pulmonary embolism
• pancreatitis
• ultrasound
• mandibular fracture

Best evidence topic reports (BETs) summarise the evidence pertaining to particular clinical questions. They are not systematic reviews, but rather contain the best (highest level) evidence that can be practically obtained by busy practising clinicians. The search strategies used to find the best evidence are reported in detail in order to allow clinicians to update searches whenever necessary. The BETs published below were first reported at the Critical Appraisal Journal Club at the Manchester Royal Infirmary¹ or placed on the BestBETs web site. Each BET has been constructed in the four stages that have been described elsewhere. ² The BETs shown here together with those published previously and those currently under construction can be seen at http://www.bestbets.org.³ Six BETs are included in this issue of the journal.

• Oxygen therapy in acute stroke

• CT pulmonary angiogram compared with ventilation-perfusion scan for the diagnosis of pulmonary embolism in patients with cardiorespiratory disease

• Combining clinical probability and ventilation-perfusion scan for diagnosis of pulmonary embolism

• Serum amylase and acute pancreatitis

• Ultrasonic guidance and the complications of central line placement in the emergency department

• The utility of the tongue blade test for the diagnosis of mandibular fracture