Effect oflungtransplantation on diaphragmatic function inpatients withchronic obstructive pulmonary disease

Background -Todatetherearenodata ontheeffects oflungtransplantation on diaphragmatic function inpatients with endstagechronic obstructive pulmonary disease (COPD).Itisnotknownwhether the relationbetweenthe transdiaphragmaticpressure(PDI)and lung volumeisalteredin recipients after transplantation asa result ofchanges indiaphragmatic structure causedby chronichyperinflation. The effect of lungtransplantation on diaphragmatic strength wasdetermined inpatients with COPD andtherelation betweenpostoperative PDIandlungvolumeanalysed. Methods- Diaphragmatic strength was assessed ineightdoublelungtransplant recipients, sixsinglelungtransplant recipients, andin14patients withCOPD whoselungfunctionwas similarto thoseofthetransplant recipients preoperatively. PDIobtained duringunilateral andbilateral phrenic nervestimulation at1Hz (twitch PDI)atfunctional residual capacity (FRC)andduring maximalsniff manoeuvres(sniff PDI)atvariouslevels ofinspiratory vital capacity (VCin)servedas parametersfordiaphragmatic strength. Sniff PDIassessed atthevarious VCinlevels wereusedto analyse thePDI/lung volumerelation. Results -Lungtransplantation causeda reduction inlungvolume,especially in thedoublelungtransplant recipients. As aconsequence sniff PDIwashigher inthe doublelungtransplant recipients thanin thepatients withCOPD atalllevels of VCinanalysed. However, sniff PDIvalues analysed at comparableintrathoracic gasvolumeswerenotreducedinthe patients withCOPD when compared withthosewho underwentlungtransplantation. Bilateral twitchPDIvalues weresimilar inthepatients withCOPD andinthelungtransplant recipients. In thesinglelungtransplant recipients unilateral twitchPDIvalues weresimilar on thetransplanted andthenon-transplanted side.The relation betweenPDI and lungvolumewas similarin the patients withCOPD and in thelung transplant recipients.