ABSTRACT

An anaesthetic approach and surgery are important treatment strategies in patients with thyroid dysfunction due to potential complications. We investigated the prevalence of thyroid disorders, the significance of thyroid function tests (TFTs) with respect to anaesthesia in the preoperative period and the need for routine examinations.

A total of 10,600 patients who were admitted to the anaesthesiology outpatient clinic for surgery were retrospectively screened and enrolled between 2011 and 2013. Evident hypothyroidism was defined as free tetra-iodothyronine (fT4) <0.7 ng dL−1 and thyroid-stimulating hormone (TSH) >4 mIU mL−1, and subclinical hypothyroidism was defined as TSH >4 mIU mL−1 with normal free hormone levels. Evident hyperthyroidism was defined as fT4 >1.7 ng dL−1 and TSH <0.1 mIU mL−1, and subclinical hyperthyroidism was defined as TSH <0.1 mIU mL−1 with normal free hormone levels. Statistical analysis was conducted using the Statistical Package for the Social Sciences (SPSS) version 17.0. Independent samples t-test and one-way analysis of variance were used to compare the difference between groups.

Of the participants, 8.5% were found to have hypothyroidism, 2.5% had hyperthyroidism, 3.5% received treatment and 2.5% had their treatment postponed. The likelihood of hypothyroidism was greater among females, and no difference was found between genders with respect to hyperthyroidism.

We believe that TFTs are important because of regional factors. However, given the high cost of TFTs and because thyroid dysfunction risk increases with age, we concluded that routine TFTs in young patients with normal physical examination findings are not mandatory.

Keywords: Thyroid function tests, hypothyroidism, hyperthyroidism, iodine