Renal sodium excretory function during acute oxygen administration.
To evaluate the effect of O2 administration and O2 removal on renal Na+ excretion, 12 hypoxemic eucapnic patients affected by chronic obstructive pulmonary disease (COPD) and 9 normal subjects were studied. After 1 h in the supine position, O2 was administered for 3 h by a tight-fitting face-mask. Urine and blood samples for renal Na+ excretion evaluation were taken at times 0, 60 and 180 min. After O2 removal both the blood and the urine samples were taken again for a further 3 h. In normal subjects, urinary Na+ excretion did not vary after both O2 administration and removal. On the contrary, in patients affected by COPD renal Na+ excretion significantly increased during O2 administration (from basal values of 0.08 +/- 0.01 to 0.17 +/- 0.02 mEq/min at 180 min, p < 0.05), and returned to baseline levels (0.13 +/- 0.03 mEq/min) after 3 h from O2 removal. The basal fractional excretion of filtered Na+ was significant lower in hypoxemic patients than in normal subjects (0.72 +/- 0.3% in patients with COPD vs. 0.95 +/- 0.7% in normal subjects, p < 0.05), while, at the end of O2 administration, it became higher in patients with COPD than in controls (1.62 +/- 0.4% in patients with COPD vs. 0.89 +/- 0.5 in control subjects, p < 0.001). In conclusion, our findings showed an oxygen-related increase of both the urinary Na+ excretion and the fractional excretion of filtered sodium in patients affected by COPD.
De Siati
L
L
University of Rome La Sapienza, Institute of I Clinica Medica, Andrea Cesalpino Foundation, Italy.
Baldoncini
R
R
Coassin
S
S
De Angelis
C
C
Ferri
C
C
Santucci
A
A
Perrone
A
A
Balsano
F
F
D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008173:Lung Diseases, Obstructive / Q000378:metabolism / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D012964:Sodium / Q000378:metabolism*
D002245:Carbon Dioxide; D012964:Sodium; D010100:Oxygen