RESPIRO trial: Rib fracture analgesia with Erector Spinae Plane Catheter comparing efficacy of continuous Infusion versus intermittent bolus regimen

Programmed intermittent bolus regimen of local anaesthetic via a erector spinae catheter for posterior rib fracture analgesia 1. ESP catheter would be inserted by an experienced regional anaesthetist aided by a trained assistant. 2. Monitoring - 3 electrode ECG, pulse oximeter and non-invasive blood pressure 3. Vertebral level selected to correspond to the approximate mid-point of the extent of fractured ribs 4. Sitting or lateral position based on the preference of the patient and the proceduralist 5. A linear array high frequency ultrasound transducer would be used in the parasagittal plane to identify the transverse process and erector spinae muscle 6. Strict aseptic precautions and local skin infiltration with 1% Lignocaine. 7. A catheter would be inserted in the plane to contact the transverse process, and a myofascial plane deep to the erector spinae muscle identified. 8. After the erector spinae plane (ESP) is identified using 5-10ml of 0.9% normal saline the catheter would then be secured with at least 1-2 centimetres of the catheter left in the ESP 9. 24 ml of 0.2% ropivacaine would then be injected under ultrasound guidance. If spread is not visualised, the ESP catheter would be reinserted. 10. Adequacy of catheter location will be confirmed by another researcher not associated with patient recruitment or clinical performance, who will adjudicate if the catheter was placed in the correct plane using saved ultrasonographic images showing at least one of the following features: • Hydro dissection • Colour doppler cranio-caudal spread • Catheter visualisation 11. Histoacryl glue (TBA) would be used to seal the skin puncture site to prevent LA leak. 12. The catheter would be secured using Steri-StripTM (3M Nexcare, USA) and transparent adhesive dressing (TegadermTM, 3M, Maplewood, MN, USA). Catheter will be non tunnelled. 13. Monitoring would be continued for 30 minutes after the procedure. 14. All participants would be initiated on patient-controlled analgesia (PCA)Choice of opioid and bolus dosage at initiation is as below, and usage would be converted using oMEDD. A lockout period of 5 minutes and no background infusion will be programmed. Drugs used in PCA: Fentanyl (dosages administered 10mcg, 15 mcg and 20 mcg), Oxycodone (dosages administered 1mg, 1.5mg, 2mg), Hydromorphone (dosages administered 200mcg, 300 mcg, 400mcg) as lowest dose, first increment and second increments respectively. 1. Inadequate analgesia defined by an NRS score = 7, or less than a 2-point fall in NRS will be managed by APS as per protocol. 1 hour after the rescue measure, the adequacy of analgesia will be reassessed. Each use of rescue analgesia and timing will be recorded. The dosage will be PCA will be continued for 48 hours and then as per the discretion of acute pain service. 15. Both groups would receive paracetamol 1g 6 hourly orally or intravenously and celecoxib 100 to 200mg mg twice a day if not contraindicated. These will be continued for 48 hours and then as per the discretion of acute pain service. 16. All other analgesics including tramadol, pregabalin, ketamine, tapentadol and tricyclic antidepressants would not be initiated. Analgesics for chronic pain conditions in those who did not meet the exclusion threshold will be continued. 17. If the participant has been allocated to Group PIB (Programmed intermittent bolus): After a delay of 1 hour following catheter insertion, 24 ml of 0.2% ropivacaine would be administered as programmed intermittent bolus every 3 hours. No background infusion would be used. This will be continued for 48 hours and then as per the discretion of acute pain service.