Regional ventilation of patients with hemidiaphragm paralysis by electrical impedance tomography

INTRODUCTION: Pulmonary ventilation is decreased in patients with hemidiaphragmatic paralysis (HDP) and changes in regional ventilation and breathlessness caused by different body positions is not clear. OBJECTIVE: Describe the ventilation distribution and breathlessness in HDP at different positions and compare to controls. METHODS: 9 patients with left HDP (7 male, 55,7±11,6 y) and 8 male healthy volunteers (27.6±3.7 y) underwent to electrical impedance tomography (EIT) to measure left (LV) and right (RV) ventilation during quiet breathing on diferent positions: seated, left (LLD) and right (RLD) lateral decubitus and supine. EIT belt was between 6th and 7th intercostal space. RESULTS: Volunteers showed more symmetric ventilation distribution when seated and supine. On both lateral decubitus there was an increase of ventilation in dependent lung. Patients had less ventilation in left lung in all positions with significant differences compared with volunteers when seated, in LLD and supine. Dyspnea was present on LLD. CONCLUSION: In healthy people, lateral decubitus increases the regional ventilation. Patients with left HDP, however, have disproportionate ventilation on all positions and are not able to compensate the dependent lung ventilation on left decubitus, with more dyspnea.