Bratel T, Ljungman S, Runold M, Stenvinkel P
Division of Respiratory Medicine, Department of Medicine, Karolinska Hospital, Stockholm, Sweden.
Respir Med. 2003 Apr;97(4):308-16. doi: 10.1053/rmed.2002.1401.
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 (C(In)) and para-amino-hippurate (C(PAH)) and orally supplemented lithium (C(Li)) and of circulating sodium (C(Na)). The 19 patients had a mean PaO2 of 7.63 +/- 1.08 kPa, a PaCO2 of 5.98 +/- 0.85 kPa, a mean nocturnal oxygen saturation (MnSaO2) of 87.7 +/- 2.8% and an FEV1 in %P of 25.6 +/- 14.6%. C(In) and C(PAH) were 35 and 45% lower than normal, respectively, whereas C(In)/C(PAH)=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 MnSaO2 correlated with reductions in post-treatment (FF) (r=0.73, P<0.05). Post-treatment PaCO2 did not change significantly in patients treated with oral diuretics, but increased (P<0.05) in patients without diuretics. C(Na) decreased after LTOT in six patients with an increase in PaCO2>6%, but C(Na) increased in four patients with unchanged or decreased PaCO2 following LTOT.
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 increased PaCO2.
肾功能受损是水肿形成的重要原因，水肿常发生于重度慢性阻塞性肺疾病（COPD）患者。在本研究中，对19例血清肌酐水平正常的COPD患者测定了夜间低氧血症（通过夜间脉搏血氧饱和度测定）对肾功能的影响。对12例患者评估了缓解夜间低氧血症[采用6个月的长期氧疗（LTOT）]对肾功能的影响。通过测定静脉注射菊粉（C(In)）、对氨基马尿酸（C(PAH)）、口服补充锂（C(Li)）以及循环钠（C(Na)）的清除率来评估肾功能。19例患者的平均动脉血氧分压（PaO2）为7.63±1.08 kPa，动脉血二氧化碳分压（PaCO2）为5.98±0.85 kPa，平均夜间血氧饱和度（MnSaO2）为87.7±2.8%，第1秒用力呼气容积占预计值百分比（FEV1%P）为25.6±14.6%。C(In)和C(PAH)分别比正常水平低35%和45%，而C(In)/C(PAH)=滤过分数（FF）比正常水平高31%。12例患者进行6个月的LTOT后，整个研究组的肾功能未出现任何显著变化。然而，治疗前低MnSaO2与治疗后（FF）降低相关（r=0.73，P<0.05）。口服利尿剂治疗的患者治疗后PaCO2无显著变化，但未使用利尿剂的患者PaCO2升高（P<0.05）。6例PaCO2升高>6%的患者LTOT后C(Na)降低，但4例LTOT后PaCO2未改变或降低的患者C(Na)升高。
低氧血症性COPD患者的肾功能（包括滤过分数）受损。仅在治疗前严重低氧血症的患者中，6个月的LTOT后滤过分数降低，且如果氧合改善未伴随PaCO2升高，钠清除率似乎会增加。
