Rectus sheath block a retrospective review of a novel adjunct for treatment of the injection site pain associated with treprostinil subcutaneous infusion in pulmonary hypertension case series.

Introduction: Subcutaneous (SC) treprostinil is an effective treatment for severe pulmonary arterial hypertension (PAH). 85% of the treated patients experience challenging infusion site pain with limited effective options.

Patient and methods: We retrospectively reviewed 11 patients who underwent 23 RSB before treprostinil SC infusion. The collected data included the type of PAH, demographics, treprostinil infusion rate, pain scores, pain therapies, block details, and the patients' perspective. Paired within-patient analyses assessed the effect of RSB on pain scores and opioid requirement during the first week.

Results: Pain reduction was most notable during Days 1-5, with significantly lower visual analogue scale (VAS) scores on Day 1 (p = 0.007), Day 3 (p = 0.011), and day 5 (p = 0.014) compared with sites managed without block. Peak pain occurred on Day 5 with the median highest VAS significantly lower with RSB (3.5 [IQR 1-5] vs 5.5 [IQR 4-9.25]). A transient reduction in opioid requirement was observed on Day 1, but it was not sustained afterwards.

Conclusion: RSB may be a useful adjuvant on the initial days of treprostinil SC infusion. Given the small sample size and retrospective, within-patient observational design, these findings are exploratory and require confirmation in prospective controlled studies.