The preoperative use of iodine solution in thyrotoxic patients prepared with propranolol. Is it necessary?

Despite the numerous reports documenting the safety and efficacy of the use of propranolol, a selective beta-adrenergic blocker, as the sole agent for preoperative preparation of a hyperthyroid patient, many surgeons continue to add a solution containing iodine to the treatment regimen. The rationale for the concomitant use of iodine solution and propranolol is that the iodine solution reduces the amount of propranolol required to make the patient symptomatically euthyroid and that iodine administration reduces the vascularity of the gland, thereby minimizing intraoperative blood loss. To ascertain the validity of these beliefs, we retrospectively reviewed our experience with 42 consecutive hyperthyroid patients who underwent subtotal thyroidectomy. These patients either received propranolol alone (20 patients) or propranolol with iodine solution (22 patients) for preoperative preparation. Comparison of the medication doses, estimated blood loss, and postoperative changes in hemoglobin and hemocrit using the Student's t-test, failed to demonstrate any significant difference between the two treatment protocols (P greater than 0.1). We conclude that the addition of iodine to propranolol for preoperative preparation of hyperthyroid patients does not result in any significant advantage over the use of propranolol alone.