Erector Spinae Plane block with fascial plane catheter for the Early Analgesia of Rib fractures in trauma (ESPEAR): a multicentre feasibility randomised trial.

Background: Traumatic rib fractures cause significant acute pain. Patients are at risk of hypoventilation, atelectasis, hypoxia, retained secretions, pneumonia, respiratory failure, and death. Effective analgesia is thought to reduce these adverse outcomes. There is widespread variation in analgesic treatments given to patients including oral, intravenous, and epidural routes of administration. Erector spinae plane (ESP) block, a novel regional analgesic technique, may be effective, but high-quality evidence is lacking. Methods: To determine if a definitive trial of ESP block and catheter in rib fractures is possible, we conducted a multicentre, randomised, controlled pilot study with feasibility assessment. Adults with rib fractures were randomised in a 1:1 ratio to either (i) ESP blockade and catheter, or (ii) placebo ESP blockade and catheter, both for 72 h. In addition, all participants received multimodal analgesia. Participants and outcome assessors were blinded. The primary feasibility outcomes were recruitment rate (target: ≥1.11 participants/site/month), retention rate (target: ≥80%), and trial acceptability assessed by staff interview. Pre-specified red-amber-green criteria were agreed to determine feasibility of a future definitive clinical trial on this topic. Results: Twenty-five participants (mean [standard deviation] age 57 [16] yr, number of rib fractures 5 [3]) were recruited from three UK major trauma centres at a rate of 0.69 participants per site per month. Retention to 6-week follow-up was 80%. Based on our criteria, the current study design is not feasible for adoption into a definitive trial. For future research in this area, we recommend substantial modification to (i) the intervention, (ii) means of bias reduction, and (iii) timing and nature of outcome measure assessments. Conclusions: Based on pre-specified criteria, a definitive examination of the clinical effectiveness of ESP block in the analgesic management of adults after blunt force chest wall injury is only feasible if substantial amendments to trial processes piloted in this study are undertaken. An open-label assessment of single-shot ESP block, applying patient-reported average pain intensity of the first 24 h as the primary outcome, and conducted at sites with established ESP analgesic pathways, may overcome the most significant feasibility barriers identified by the present study. Clinical trial registration: ISRCTN49307616.