Vaziri Nosratola D, Khazaeli Mahyar, Nunes Ane C F, Harley Kevin T, Said Hyder, Alipour Omeed, Lau Wei Ling, Pahl Madeleine V
Division of Nephrology and Hypertension, University of California, Irvine, Irvine, California, USA.
Hemodial Int. 2017 Jul;21(3):343-347. doi: 10.1111/hdi.12510. Epub 2016 Nov 1.
Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here.
Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured.
No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P < 0.001) which was paradoxically accompanied by a modest but significant (P < 0.05) rise in blood ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P < 0.01). On subgroup analysis of patients who had a rise in blood ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P < 0.01). The nadir intradialytic systolic blood pressure trended lower in the hemodialysis patients who had a rise in blood ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27).
Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure.
尿毒症会导致一种特征性的呼吸气味（尿毒症口臭），这主要归因于其高氨含量。早期研究表明，呼出气体中的氨与血尿素水平之间存在很强的相关性，并且慢性肾病患者在血液透析后呼出气体中的氨含量降低了10倍。呼出气体中氨的潜在来源包括：（i）口腔和呼吸道中的细菌菌群将尿素水解产生局部氨，以及（ii）肺释放循环血液中的氨。虽然尿毒症和血液透析对呼出气体中氨的影响是众所周知的，但它们对血氨的影响尚不清楚，本文对此进行了探讨。
采集了23名血液透析患者（透析前和透析后即刻）、14名腹膜透析患者和10名健康对照者的血样。测量了血液中的氨、肌酐、尿素和电解质水平。
血液透析组、腹膜透析组和对照组的基线血氨水平无显著差异。血液透析过程导致尿素浓度显著降低（P<0.001），但在23名研究患者中的10名患者中，反常地伴随着血氨水平适度但显著（P<0.05）升高。血液透析前后血氨的变化与血清碳酸氢盐水平的变化相关（r = 0.61，P<0.01）。在对透析后血氨水平升高的患者进行亚组分析时，发现与平均动脉压下降有很强的相关性（r = 0.88，P<0.01）。与血氨降低的患者相比，血氨升高的血液透析患者透析期间收缩压最低点的趋势更低（分别为124±8 vs. 136±6 mmHg，P = 0.27）。
在研究的患者中，43%的患者在血液透析后血尿素降低的同时，血氨水平适度升高，这与先前报道的血液透析对呼出气体中氨的影响形成对比。在这一亚组患者中，血液透析期间血氨的变化与血碳酸氢盐升高和平均动脉血压下降相关。
