Effects of Haemodialysis on Pulmonary Clearance of Tc-99m Diethylene Triamine Pentaacetate (DTPA)

Abstract

Objectives: Hypoxaemia occurring during haemodialysis has long been known. Several mechanisms in the pathogenesis have been proposed. The present study was conducted to test whether changes in pulmonary alveolar permeability were among the operating mechanisms. Materials and methods: Twenty haemodialysis patients (12 male, 8 female) were included in the study. The mean age was 49 years (age range: 18-85 years). Patients with known pulmonary disease, current smokers and those gaining more than 1 kg weight during the interdialytic period were excluded. Complete blood count, arterial blood gas analysis, pulmonary function tests and Tc-99m diethylene triamine pentaacetate (DTPA) inhalation scintiscan were carried out before and after haemodialysis. A bronchial provocation test was carried out after each session. A postero-anterior chest radiogram was taken for each patient. Results: When the results before and after haemodialysis were compared, it was observed that the pH and serum bicarbonate levels, haemoglobin and haematocrit values were significantly higher after haemodialysis. However, the platelet count was found to be decreased significantly. Bronchial hyperreactivity, tested by metacholine, was positive in 5 of 19 patients (26%). No correlation between bronchial hyperreactivity and other factors could be identified. No significant difference was observed in pulmonary Tc-99m DTPA clearance after haemodialysis. All chest radiograms were interpreted to be within normal limits. Conclusions: Since we observed no hypoxaemia following haemodialysis, we cannot comment as to whether the changes in pulmonary clearance play a role in the pathogenesis of haemodialysis-associated hypoxaemia. In order to reach reliable conclusions, additional studies are needed.