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

Abstract

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, FIF_50% and FEF_50%/FIF_50% (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 FIF_50%, FEF_50%/FIF_50% ratio and a graphic plot of the flow volume loop curve before and three, six and 12 months after treatment with ¹³¹I. FIF_50% 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 FEF_50%/FIF_50% ratio decreased from in 1.45 (0.32–2.26) to 1.03 (0.43–2.13) 12 months after treatment (p<0.001). A progressive decrease was seen over time (p=0.001, trend analysis). By visual evaluation 11 had a flow volume loop curve typical for an upper airway obstruction and in 9 patients the FEF_50%/FIF_50% ratio was >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 FEF_50% and FIF_50% are important estimates for upper airway obstruction in these patients.