ORTHOSTATIC HYPOXEMIA IN DIALYZED ADULT POLYCYSTIC KIDNEY-DISEASE PATIENTS

Background. Recently we observed a unique clinical phenomenon, namely, orthostatic or postural hyperaemia in a 72-year-old female adult poly cystic kidney disease (APKD) patient, maintained on CAPD. Extensive in vestigations failed to yield a satisfactory explanation for her ambula tory hypoxaemia. Methods. To validate our observation, 15 dialysed pat ients underwent blood gases analyses in both the supine and ambulatory positions (SpO(2) and ApO(2) respectively). Patients were divided int o two groups: group 1 (n-7) whose end-stage renal failure (ESRF) was d ue to APKD and group 2 (n-8) in whom ESRF was due to other causes. Bot h haemodialysed (HD) and CAPD patients were included. ApO(2) was deter mined as the pO(2) immediately upon standing up. Readings in HD patien ts were taken at the end of the dialysis session, that is, at the pati ents' dry weight. Results, Respective SpO(2) and ApO(2) of the two gro ups were 85 +/- 17.1 and 78 +/- 20.5 vs 85.8 +/- 19 and 91 +/- 21 mmHg . Delta change in pO(2) defined as the mean decrease (negative value) or mean increase (positive value) of ApO(2) in relation to SpO(2) was -7.85 (group 1) vs + 5.2mmHg (group 2), P<0.005. In group 1, six of se ven patients demonstrated a negative delta. In group 2, four of eight showed a positive delta whilst the remaining four had no change in the delta value. Conclusion. Orthostatic hypoxaemia may occur in dialysed patients whose ESRF is due to APKD.