Evaluation of pulmonary function in renal transplant recipients and chronic renal failure patients undergoing maintenance hemodialysis

BackgroundImpaired pulmonary function in patients on hemodialysis may be caused by an underlying pulmonary disease, however the effects of hemodialysis treatment and kidney transplantation are not well understood.Aim of the workThe aim of this study was to evaluate pulmonary function among patients with chronic renal failure (CRF) undergoing hemodialysis and patients with kidney transplant.Patients and methodsThis study was conducted on 60 subjects. They were classified into 3 groups: Hemodialysis group (HDG) included 20 patients with end stage renal disease (ESRD) on regular hemodialysis for at least six months and were clinically stable. Transplant group (TG) included 20 patients who had undergone kidney transplant at least six months earlier and were also clinically stable. Control group (CG) included 20 apparently healthy subjects. All subjects underwent pulmonary function testing; including resting spirometry included flow volume loop and Maximal Voluntary Ventilation (MVV), measurement of lung volumes and diffusing capacity for carbon monoxide (DLCO) using single breath technique, Six Minute Walking Test (6MWT) and arterial blood gases (ABG).ResultsThere was a significant difference between HDG, TG and CG regarding FVC% of predicted, FEV1% of predicted, FEF 25–75% of predicted, PEFR% of predicted and MVV% of predicted. Also there was a statistically significant difference between HDG, TG and CG regarding RV% of predicted, TLC% of predicted and RV/TLC%. Although FVC% of predicted and FEV1% of predicted were within the normal range in the 3 studied groups, there was a statistically significant reduction in these spirometric parameters in HDG more than that in the TG and CG, also reduction in TG more than CG. FEF 25–75% of predicted was less than normal in HDG and was within the normal range in TG and CG, also RV% of predicted and TLC% of predicted were increased in HDG more than that in TG and CG. Regarding DLco% of predicted we found significant differences between the 3 studied groups. It was lower in HDG than in TG and CG. Also the same results we found regarding Dlco/VA% of predicted. There were statistically significant differences among the studied groups regarding 6MWT. Regarding ABG although all values were within normal levels, Pao2 in HDG was less than that in TG and CG.ConclusionThere is impairment of lung function in patients with CRF undergoing hemodialysis. The main changes are small airway obstruction, reduction in carbon monoxide transfer and diminished 6MWT that were not completely improved in the kidney transplant patients.