**3. Preoperative evaluation**

Adequate history and physical examination are essential in the preoperative diagnosis and evaluation of the patient being worked up for tonsillectomy. History alone is the most common method for diagnosing obstructive sleep apnea.10 When the diagnosis is at all in question, the child is younger than 2 years, or there is concern about the severity of the sleep apnea, a polysomnogram should be recommended.11Preoperative electrocardiogram and chest x-ray are not necessary unless there is a history of heart disease.12 Other preoperative evaluation needs to be decided based on the medical conditions of each individual patient. For example, a child with von Willebrand disease should have the input of a hematologist regarding the use of desmopressin to minimize the risk of bleeding during the intraoperative and post-operative periods.
