BEST EVIDENCE TOPIC REPORTS Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary

A short cut review was carried out to establish whether transthoracic ultrasound can be used to diagnose pneumothoraces in trauma patients. A total of 46 papers were found using the reported search, of which four represented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated. Clinical scenario A 35 year old male is brought into the emergency department after falling from a height. He is tachypnoeic and tachycardic and has tenderness in the left anterior chest and left upper abdomen. Your department has an ultrasound scanner and this is used to assess the patient’s abdomen. You wonder whether it could also be used to diagnose a pneumothorax. Three part question In a [patient with chest trauma] can [transthoracic ultrasonography] accurately diagnose [a traumatic pneumothorax]. Search strategy Medline 1951 to December 2004 using the Dialog Datastar interface. [(pneumothorax#.W.DE OR pneumothorax) AND (ultrason$12) AND (wounds.and.injuries#.DE. OR trauma)] Editor’s note: In OVID Medline an equivalent search strategy would be: [exp pneumothorax/OR pneumothorax. mp] AND [ultras$12.mp] AND [exp wounds and injuries/OR trauma.mp] Search outcome Altogether 46 papers were found of which four were relevant to the three part question (table 1). Comments These studies were relatively small and only two were obviously blinded. Sensitivity for pneumothorax reported varied between 58.9% and 100% and specificity varied between 94% and 100%. It is interesting to note that the study with the lowest sensitivity used CT as part of the gold standard. In such cases CT may be able to find small pneumothoraces not visible on CXR. The clinical relevance of such small pneumothoraces in the resuscitation room is debatable (unless intermittent positive pressure ventilator (IPPV) is being considered). All ultrasound examinations are known to be operator dependent. There is some variation in the ultrasonographic signs used to confirm pneumothorax. c CLINICAL BOTTOM LINE Rapid and accurate bedside ultrasound performed by emergency physicians can be used to diagnose pneumothorax after chest trauma. The clinical role of this in the resuscitation of trauma patients is not clear. Dulchavsky SA, Schwarz KL, Kirkpatrick AW, et al. Prospective evaluation of thoracic ultrasound in the detection of pneumothorax. J Trauma 2001;50:201–5. Knudtson JL, Dort JM, Helmer SD, et al. Surgeon-performed ultrasound for pneumothorax in the trauma suite. J Trauma 2004;56:527–30. 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. Each BET is based on a clinical scenario and ends with a clinical bottom line which indicates, in the light of the evidence found, what the reporting clinician would do if faced with the same scenario again. The BETs published below were first reported at the Critical Appraisal Journal Club at the Manchester Royal Infirmary or placed on the BestBETs website. Each BET has been constructed in the four stages that have been described elsewhere. The BETs shown here together with those published previously and those currently under construction can be seen at http://www.bestbets.org. Four BETs are included in this issue of the journal. c Transthoracic ultrasonography to diagnose pneumothorax in trauma c Early mobilisation for volar plate avulsion fractures c Do we need to give steroids in children with Bell’s palsy? c Topical anaesthetic versus lidocaine infiltration to allow closure of skin wounds in children S D Carley, Department of Emergency Medicine, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK; [email protected] 1 Carley SD, Mackway-Jones K, Jones A, et al. Moving towards evidence based emergency medicine: use of a structured critical appraisal journal club. J Accid Emerg Med 1998;15:220–2. 2 Mackway-Jones K, Carley SD, Morton RJ, et al. The best evidence topic report: a modified CAT for summarising the available evidence in emergency medicine. J Accid Emerg Med 1998;15:222–6. 3 Mackway-Jones K, Carley SD. bestbets.org: odds on favourite for evidence in emergency medicine reaches the worldwide web. J Accid Emerg Med 2000;17:235–6. 504 www.emjonline.com group.bmj.com on September 6, 2017 Published by http://emj.bmj.com/ Downloaded from