Local anaesthetic delivery regimens for peripheral nerve catheters: a systematic review and network meta-analysis

There are numerous possible techniques for delivering local anaesthetic through peripheral nerve catheters. These include continuous infusions, patient-controlled boluses and programmed intermittent boluses. The optimal delivery regimen of local anaesthetic is yet to be conclusively established. In this review, we identified prospective trials of delivery regimens through peripheral nerve catheters. Our primary outcome was visual analogue scale scores for pain at 48 h. Secondary outcomes were: visual analogue scores at 24 h; patient satisfaction scores; rescue opioid use; local anaesthetic consumption; and nausea and vomiting. Network meta-analysis was used to compare these outcomes. Predefined sub-group analyses were performed. Thirty-three studies enrolling 1934 participants were included. In comparison with continuous infusion, programmed intermittent boluses improved visual analogue pain scores at both 48 and 24 h, the weighted mean difference (95%CI) being -0.63 (-1.12 to -0.14), p = 0.012 and -0.48 (-0.92 to -0.03), p = 0.034, respectively. Programmed intermittent boluses also improved satisfaction scores, the weighted mean difference (95%CI) being 0.70 (0.10-1.31), p = 0.023, and reduced rescue opioid use, the weighted mean difference (95%CI) in oral morphine equivalent at 24 h being -23.84 mg (-43.90 mg to -3.77 mg), p = 0.020. Sub-group analysis revealed that these findings were mostly confined to lower limb and truncal catheter studies; there were few studies of programmed intermittent boluses for upper limb catheters. Programmed intermittent boluses may provide optimal delivery of a local anaesthetic through peripheral nerve catheters. Further research is warranted, particularly to delineate the differences between upper and lower limb catheter locations, which will help clarify the clinical relevance of these findings.