Elsevier

Respiratory Medicine

Volume 97, Issue 4, April 2003, Pages 308-316
Respiratory Medicine

Regular Article
Renal function in hypoxaemic chronic obstructive pulmonary disease: effects of long-term oxygen treatment

https://doi.org/10.1053/rmed.2002.1401Get rights and content
Under an Elsevier user license
open archive

Abstract

Impaired renal function is an important cause for the oedema formation, which often occurs in severe chronic obstructive pulmonary disease (COPD).

In the present study, the importance of nocturnal hypoxaemia (measured by a nocturnal pulse oximetry) for the renal function was determined in 19 COPD patients, with normal levels of serum creatinine. The effects on kidney function of alleviating the nocturnal hypoxaemia [using 6 months of long-term oxygen treatment (LTOT)], was assessed in 12 patients. Renal function was assessed by determining the clearances of intravenously administered inulin (CIn) and para-amino-hippurate (CPAH) and orally supplemented lithium (CLi) and of circulating sodium (CNa). The 19 patients had a mean P aO2 of 7.63±1.08 kPa, a P aCO2 of 5.98±0.85kPa, a mean nocturnal oxygen saturation (Mn S aO2) of 87.7±2.8% and an FEV1 in %P of 25.6±14.6%. CIn and CPAH were 35 and 45% lower than normal, respectively, whereasCIn /CPAH=filtration fraction (FF) was 31% higher than normal. Six months of LTOT in 12 of the patients was not followed by any significant change in renal function in the entire study group. However, low pretreatment Mn S aO2 correlated with reductions in post-treatment (FF) (r=0.73,P <0.05). Post-treatment P aCO2 did not change significantly in patients treated with oral diuretics, but increased (P<0.05) in patients without diuretics. CNa decreased after LTOT in six patients with an increase in P aCO2 >6%, but CNa increased in four patients with unchanged or decreased P aCO2 following LTOT. Conclusions: Renal function (including filtration fraction) is impaired in hypoxaemic COPD. Filtration fraction is decreased following 6 months of LTOT solely in patients with severe pretreatment hypoxaemia and sodium clearance seems to be increased if improved oxygenation is not accompanied by increasedP aCO2.

Keywords

renal function
inuline clearance
para-amino-hippurate clearance
lithium clearance
sodium clearance
filtration fraction
nocturnal hypoxaemia
long-term oxygen treatment
chronic obstructive pulmonary disease
hypercapnia.

Cited by (0)

f1

Correspondence should be addressed to: Dr Tomas Bratel, MD, Division of Respiratory Medicine, Department of Medicine, Karolinska Hospital, S-171 76 Stockholm, Sweden. Fax: +46 8 33 29 98; E-mail: [email protected]