Background and Aims The erector spinae plane (ESP) block is safe and effective following traumatic rib fracture¹. The optimal regimen for local anaesthetic (LA) administration remains unknown. At our institution patients receive either a continuous infusion of 0.125% bupivacaine (up to 10 ml/h, 20 ml boluses 6 hourly as required), or a patient controlled regional anaesthesia (PCRA) regimen (4 ml/h background rate, 30 ml boluses, lockout time 4h). We aimed to identify and standardise best practice.

Methods Following approval by local audit department, a retrospective case note review was performed between 1/6/21 to 30/11/21. Numerical rating pain score (0 = nil, 3 = severe) at rest and on movement, spirometry values, rescue oral opioid administration were assessed for the first 72h, and mean LA usage per day across the entire catheter duration. The impact of associated pulmonary injury on total catheter duration was also assessed.

Results 21 patient received ESP catheters. Mean catheter duration was 4.8 days (SD 1.6). The 12 patients with an associated pneumothorax, haemothorax or pulmonary contusion had a longer catheter duration (5.4 days, 95% CI 4.6 – 6.3) compared to those without (4.7 days, 95% CI 2.9 – 5.3), although this did not reach statistical significance (p = 0.06). No significant difference was found in any of the parameters studied (table 1).

Conclusions Our local data demonstrates that both regimens provide equivalent analgesic and respiratory effect, without affecting LA consumption. This provides flexibility, allowing an individualised approach to managing these patients, taking in to account patient preference, ability to comply with a PCRA regimen, and local resources.