Efficacy and safety of different Adrenaline concentrations in endoscopic dacryocystorhinostomy: A systematic review and meta-analysis

Purpose This systematic review evaluates the efficacy and safety of different nasal adrenaline concentrations for bleeding control in endoscopic dacryocystorhinostomy (eDCR). Methods Following PRISMA guidelines, we searched PubMed for studies reporting bleeding and cardiovascular events in adult eDCR. Outcomes were analysed using random-effects models. Statistical analyses employed random-effects models and I 2 statistic. The protocol was registered with the Open Science Framework (OSF) (DOI: https://doi.org/10.17605/OSF.IO/EZDWG ). Results Among 103 screened articles, seven studies (comprising 856 patients) were included for meta-analysis. The 1:200,000 infiltrative adrenaline had significantly higher bleeding risk (15.3%, 95% CI: 11.1–20.5%) than 1:100,000 (3.8%, 95% CI: 2.0–6.5%) and 1:80,000 (2.0%, 95% CI: 0.7–4.3%), with an absolute risk difference of +13.3% (95% CI: + 9.8–16.8%, p < 0.0001) between 1:200,000 and 1:80,000. No significant difference existed between 1:100,000 and 1:80,000 (RD=+1.8%, 95% CI: −1.2–4.7%, p = 0.23). Each 100,000-fold dilution increased absolute bleeding risk by 12.1% ( p < 0.001), with a number needed to treat (NNT) of 8 favouring 1:80,000 or 1:100,000 over 1:200,000. The most common infiltrative concentrations (n = 8,648) were 1:100,000 (57%), 1:200,000 (23%), and 1:80,000 (18%). For topical applications ( n = 6,343), 1:1,000 (48%) and 1:100,000 (22%) predominated. While no particular topical concentration showed superior haemostasis (p > 0.05), 30-min 1:1,000 adrenaline application reduced bleeding vs. 5-min use (p < 0.05). Rare complications included ocular and cardiovascular events. Conclusions 1:100,000 or 1:80,000 infiltrative adrenaline is preferred over 1:200,000 for lower bleeding risks, while topical adrenaline benefits from prolonged 30-min application. Surgeons should remain vigilant for rare systemic complications.