Improvement of upper airway obstruction after 131I-treatment of multinodular nontoxic goiter evaluated by flow volume loop curves

Symptoms of tracheal-esophageal compression are often related to a large nontoxic goiter. The aim of the present study was to evaluate to what degree upper airway obstruction, as measured by flow volume loops, FIF50% and FEF50%/FIF50% (Forced Expiratory Flow at 50% of the vital capacity/ Forced Inspiratory Flow at 50% of the vital capacity) exists in nontoxic multinodular goiter, and whether changes occur after 131I-treatment. Thirteen patients with large multinodular non-toxic goiters were evaluated by estimation of FIF50%, FEF50%/FIF50% ratio and a graphic plot of the flow volume loop curve before and three, six and 12 months after treatment with 131I. FIF50% increased over 12 months from median 1.79 I/sec (range 1.46–3.02) to 2.84 I/sec (1.13–5.69) (p=0.01). A progressive increase was seen over time (p=0.001, trend analysis). The FEF50%/FIF50% ratio decreased from in 1.45 (0.32–2.26) to 1.03 (0.43–2.13) 12 months after treatment (p 1.2. In conclusion we found that upper airway obstruction is present in patients with multinodular nontoxic goiter, and seems to be reduced after 131I-treatment. Flow volume loop curves and measurement of FEF50% and FIF50% are important estimates for upper airway obstruction in these patients.