AIRWAY FUNCTION-TESTS AND VOCAL CORD PARALYSIS IN LUNG-TRANSPLANT RECIPIENTS

Maximum expiratory and inspiratory flow-volume (MEFV, MIFV) curves, sp ecific airway conductance (sG(aw)), and flexible fiberoptic laryngosco py were examined in 8 pediatric lung transplant recipients with vocal cord paralysis (VCP). Six were heart-lung (H-L) and 2 double-lung (D-L ) recipients, 7 had left VCP, and 1 had right VCP. Based on the pulmon ary function tests (PFT), 2 subgroups could be distinguished in the 8 recipients with VCP. Group A (5/8 recipients; mean age, 13 +/- 3.4 yea rs; mean height, 144.3 +/- 12.3 cm) had significantly reduced specific airway conductance (sG(aw); < 2 SD from predicted) and normal MEF(25) , MEF(50), peak expiratory flow (PEF), forced expiratory volume in 1 s econd (FEV(1)), and %FEV(1)/forced vital capacity (FVC); this pattern suggested variable extrathoracic airway obstruction. PIF was normal in 4/5 and reduced in 1/5 of these recipients. Group B (3/8 recipients w ith VCP; mean age, 17 +/- 2.4 years; mean height, 156.3 +/- 12.0 cm) h ad significantly reduced sG(aw), MEF(25), MEF(50), PEF, FEV(1), and %F EV(1)/FVC, implying primarily small airway obstruction. These recipien ts had bronchiolitis obliterans. The results suggest that a pattern of reduced sG(aw) and normal MEFs, PEF, FEV(1), and PIF should raise the possibility of VCP in patients after lung transplantation. sG(aw) is more sensitive than PIF and PEF in identifying airway obstruction due to VCP, and should be routinely included in the follow-up evaluation o f lung transplant recipients. (C) 1997 Wiley-Liss, Inc.