A waiting time of 7 min is sufficient to reduce bleeding in oculoplastic surgery following the administration of epinephrine together with local anaesthesia.

OBJECTIVE: The time taken to reach maximal haemostatic effect following local anaesthesia with epinephrine is generally believed to be <10 min. This is based on clinical experience and indirect measurements of perfusion using methods such as laser Doppler flowmetry and oxygen spectroscopy. However, the only study in which bleeding has been measured quantitatively in an intra-operative setting in humans showed that the full haemostatic effect was not achieved until 30 min after anaesthesia. The aim of this study was to determine the time taken to reach maximum haemostatic effect when using epinephrine for local anaesthesia in oculoplastic surgery. METHODS: Intra-operative bleeding following infiltration anaesthesia with either lidocaine 20 mg/ml (2%) or lidocaine + epinephrine 12.5 µg/ml (1:80 000) was measured after 7, 15 and 30 min in the eyelids of 16 patients undergoing upper eyelid blepharoplasty. RESULTS: Bleeding was decreased by 74.6% (with 95% CI, 6.16-87.6%) 7 min after the injection of lidocaine + epinephrine (p = 0.0048) compared with lidocaine without epinephrine. There was no further decrease in bleeding after 15 or 30 min (p = n.s.). CONCLUSION: The optimal time for skin incision in eyelid surgery is within 7 min of injection of lidocaine with epinephrine. Waiting longer does not lead to a further decrease in bleeding.