The effect of dexamethasone on duration of analgesia from fascia iliaca compartment blocks in emergency department patients with hip fractures

This study aims to assess the duration of analgesia gained from plain ropivacaine ultrasound guided fascia iliaca compartment block (USG-FICB) as compared to ropivacaine USG-FICB augmented by intracompartmental dexamethasone. Enrolled patients will be randomised to receive an USG-FICB with either ropivacaine + dexamethasone OR ropivacaine + placebo. Duration of analgesia will be assessed based on timing of breakthrough opioid following the USG-FICB. An external third party will prepare syringes containing 1 mL of either normal saline or 1 mL of dexamethasaone 4mg/mL. They will be labelled such that blinding can be maintained. e.g. "A" or "B", in identical syringes. 150 mg of ropivacaine will be diluted into 39 mL of 0.9% saline. If randomised to intervention, 1 mL of 4mg/mL dexamethasone (blinded) will be added to this syringe. This will result in a 0.375% ropivacaine and 0.1 mg/mL dexamethasone solution. If a patient weighs less than 60 kg, 30 mL of this solution will be injected into the compartment. If the patient weighs 60-70 kg, 35 mL of this solution will be injected into the compartment. If the patient weighs more than 70 kg, 40 mL of this solution will be injected into the compartment. This intervention will only occur once, close to the time of presentation and randomisation. As noted above, the dexamethasone and ropivacaine will be administered at the same time, in the same syringe. The person performing the intervention will be an emergency department doctor trained in the procedure and study protocol. Administration will be recorded in the electronic medical record, including the random allocation to "A" or "B".