Discussion
blood loss, bleeding, intraoperative bleeding, platelet aggregation
BLEEDING, CLOT, BLOOD LOSS, BLOOD CLOTS, INTRAOPERATIVE BLEEDING
Minimizing bleeding during external DCR is an important goal as bleeding can obscure the operative field especially the lacrimal sac and the nasal mucosa; and subsequently increase the DCR failure rate. Epinephrine has been widely used to reduce the per operative bleeding in many surgeries via its vasoconstrictor effect. Epinephrine also has a procoagulant effect by increasing the platelet aggregation via its alpha-adrenergic effect [Local application of TXA has been investigated in many surgical interventions to reduce intraoperative bleeding and maintain a dry surgical field with subsequently less surgical time. This addition proved its efficacy in facelift surgery [In this study, we investigated the efficacy of adding TXA to epinephrine-soaked gauze in reducing the total amount of bleeding in external DCR, aiming for the best bloodless intraoperative field during the procedure and reducing the total operative time. To our knowledge, this is the first study to investigate the use of topical TXA in external DCR.Agrwalla and Dora in 2016 assessed the efficacy of systemic administration of either oral TXA 500 mg tablets, ethamsylate tablets or botropase injection preoperatively versus placebo (Vitamin B complex) in reducing the amount of intraoperative bleeding and shortening the surgical time during lacrimal sac surgery. The authors found a significant difference in the mean operating time between the TXA group and the placebo group (30 min and 56 min, respectively). Also, the number of gauge pellets soaked with blood postoperatively was calculated and was significantly lower in the TXA group (22 pellets) versus the placebo group (38 pellets). [Our results nearly matched those of Caesar and McNab, who reported a mean time of 36 min after use of a mixture of local anaesthetic composed of a 1:1 mixture of 2% lidocaine with 1:100,000 epinephrine and bupivacaine with 1:100,000 epinephrine. Caesar and McNab also reported a mean blood loss of 4.5 mL, while in our study we reported a mean blood loss of 29.4 ± 17.1 ml in group A and 49.1 ± 18.1 ml in group B. The authors themselves stated that the reported blood losses in various studies have varied from a mean of 6.3 to 250 ml due to variable techniques used in measuring blood loss [In our study surgeon satisfaction regarding the clarity of the surgical field and the ease of surgery was compared between the two groups and graded into four grades. Although a clearer surgical field and more surgeon satisfaction were observed in group A compared to group B, statistical analysis showed no significant difference between the two groups. This may be attributed to low number in each group in relation to high number of grades of satisfaction. However, no difference in final clinical outcome over the follow-up visits was noticed.The results of this study suggest that the roles of epinephrine and TXA are complementary and the short time of action of the epinephrine could be avoided with the clot stabilization effect of TXA. This effect is supported by the laboratory work done by Zilinsky et al. in which lidocaine and adrenaline did not alter the effects of TXA on the stability and fibrinolysis of blood clots (