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Orthopnea and tidal expiratory flow limitation in patients with euthyroid goiter
Roberto Torchio1, Carlo Gulotta, Alberto Perboni
1Fisiopatologia Respiratoria, Ospedale San Luigi Gonzaga, Orbassano, Turin, Italy. r.torchio@inrete.it
Background:
Nontoxic goiters can cause extrathoracic upper airway obstruction and, if large, may extend into the thorax, causing intrathoracic airway obstruction. Although patients with goiter often report orthopnea, there are few studies on postural changes in respiratory function in these subjects.
Purpose:
The aim of this study was to investigate the postural changes in respiratory function and the presence of flow limitation (FL) and orthopnea in patients with nontoxic goiter.
Methods:
In 32 patients with nontoxic goiter, respiratory function was studied in seated and supine position. Expiratory FL was assessed with the negative expiratory pressure method. Goiter-trachea radiologic relationships were arbitrarily classified as follows: grade 1, no evidence of tracheal deviation; grade 2, tracheal deviation present in lateral and/or anteroposterior plane but with tracheal compression < 20%; and grade 3, tracheal deviation present with compression > 20%. Subgroups were considered according to this classification and occurrence of orthopnea and FL.
Results:
In all three groups of patients, the average maximal expiratory flow at 50% of FVC/maximal inspiratory flow at 50% of FVC ratios were > 1.1, suggesting the presence of upper airway obstruction. Grade 3 patients had a significantly lower expiratory reserve volume and maximal expiratory flow at 25% of FVC and higher airway resistance and 3-point FL score than patients with grade 1 and grade 2. The prevalence of orthopnea was highest in patients with grade 3 (75%, as compared to 18% in the grade 1 group). In patients with orthopnea, the prevalence of intrathoracic goiter was also higher (78%, vs 21% in patients without orthopnea).
Conclusion:
There is a high prevalence of orthopnea in patients with goiter, especially when the location is intrathoracic and causes a reduction of end-expiratory lung volume and flow reserve in the tidal volume range, promoting FL especially in supine position. Obesity is a factor that increases the risk of orthopnea in patients with goiter.