Sustained ventilation: perfusion imbalance during hemodialysis.
Five children between the ages of 6 and 15 years, who required chronic hemodialysis (HD) for renal failure, were studied to evaluate the central and pulmonary effects of HD on gas exchange. Acetate dialysate was used, and dialysate pO2 and pCO2, arterial pO2 and pCO2, endtidal CO2 and minute ventilation were measured pre-HD and 15, 30, 60, 120 and 240 minutes after commencement of HD. Arterial-alveolar CO2 gradient (aADCO2) was calculated to determine the ventilation: perfusion (V/Q) status. Minute ventilation did not change significantly from the pre-HD value of 8.9 +/- 1.1 l/min (mean +/- SD). The aADCO2 increased significantly from 3.2 +/- 3.7 mmHg to 8.4 +/- 2.4 mmHg at 15 mins (p less than .01) and was still elevated at 120 mins. (9.1 +/- 3.4 mmHg, p less than .02). There was a weak but significant inverse relationship between aADCO2 and arterial pO2 (r -0.42, p less than 0.05). The results suggest that, in these children, dialysed at altitude, dialysis-related hypoxemia appears to be the result of a sustained V/Q mismatch, possibly related to a decrease in pulmonary perfusion.
D000293:Adolescent; D000531:Altitude; D002245:Carbon Dioxide / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology*; D008168:Lung / Q000503:physiopathology*; D008297:Male; D010100:Oxygen / Q000097:blood*; D006435:Renal Dialysis; D012121:Respiration, Artificial
D002245:Carbon Dioxide; D010100:Oxygen