effect of topical and systemic tranexemic acid on bleeding during ear exploration surgery

Conditions: Intraoperative Bleeding

Summary: the effect of tranexamic acid (txa) on bleeding and improvement of surgical field during ear exploration surgery is not clear yet. this study will conducted to answer this question.

bleeding during ear surgery is still a challenge for surgeons and anesthesiologists . although extensive blood loss is rare during ear surgery, however, establishing a favorite surgical field is often difficult. the reason is that even slight bleeding may distort the view of the field and increase the occurrence of complications, including deafness, the longer duration of surgery, or even inconclusive surgery . many techniques have been proposed to improve the field of ear exploration surgery. bipolar diathermy, packing, local vasoconstrictors, and induced hypotension are the most commonly used techniques . diathermy can lead to local damage and delayed bleeding . using topical vasoconstrictions can lead to hemodynamic instability especially in patients with a history of hypertension or ischemic heart disease. induction hypotension exposes the patients to more anesthetic drugs and hence a higher risk of potential side effects. however, neither of these methods guarantees a desirable surgical field with no bleeding. therefore, investigators are working on more effective and safer methods to reduce bleeding and hence to improve the field of surgery . activation of fibrinolysis during and after surgery is a well-known phenomenon. many mechanisms associated with coagulation disorders, such as surgical trauma, blood loss and consumption of coagulation factors and platelets, using crystalloid and colloid given during and after surgery, hypothermia, acidosis, foreign materials, and etc. in recent studies, systemic infusion of anti-fibrinolytic drugs have been used to reduce bleeding in various forms of surgery such as major orthopedic surgery,and adeno-tonsillectomy. tranexamic acid (txa) is a synthetic antifibrinolytic agent that binds to the lysine binding sites of plasmin and plasminogen. saturation of the binding sites causes separation of plasminogen from superficial fibrin and hence prevents fibrinolysis. any surgical procedure can cause a considerable tissue damage and hence trigger the release of enzymes, such as 'tissue plasminogen activator' that converts plasminogen to plasmin and activates fibrinolysis process. txa can prevent fibrinolysis activity by inhibiting the activity of this enzyme. systemic infusion of txa associated with several potential side effects such as nausea, vomiting, diarrhea, allergic dermatitis, dizziness, hypotension, seizures, impaired vision, achromatopsia (impaired color vision), and particularly thromboembolic events. several studies have been conducted on topical txa in different types of surgery but no systemic absorption or side effects have been reported. to date, the effect of txa on reduction of bleeding in ear surgery is unclear . there is no consensus on the efficacy of txa and its effective dose in reducing bleeding. this trial will aim to assess the effect of topical txa on bleeding and improvement of surgical field during ear surgery in patients with chronic ear disease.

Eligibility criteria:
inclusion criteria: 1. being candidate for ear exploration surgery. 2. asa i-ii 3. willing to participate in the study 4. hb level \> 10 mg/dl. 5. normal coagulation profile (inr and ptt ) exclusion criteria: 1. patient refusal 2. allergy totxa 3. bleeding disorder 4. psychiatric illness 5. acute and chronic renal failure 6. using heparin during 48 hr before surgery 7. pregnancy 8. cirrhosis 9. colour blindness 10. cardiac stent