Department of Intensive Care Medicine, Jeroen Bosch Hospital, 's-Hertogenbosch, 5223HH, The Netherlands.
J Crit Care. 2012 Jun;27(3):255-60. doi: 10.1016/j.jcrc.2011.05.028. Epub 2011 Jul 27.
Urinary excretion of chloride corrects metabolic acidosis, but this may be hampered in patients with impaired renal function. We explored the effects of renal function on acid-base characteristics and urinary strong ion excretion using the Stewart approach in critically ill patients with metabolic acidosis.
We examined the plasma and urine chemistry in 65 critically ill (mixed medical and surgical) patients with metabolic acidosis. The apparent strong ion difference, effective strong ion difference, strong ion gap, and urinary simplified strong ion difference (urinary SID) were calculated. Linear regression analyses were used (1) to assess whether plasma creatinine concentrations were related to urinary SIDs values, adjusted for blood pH levels, and (2) to determine whether urinary SID values were associated with blood pH levels.
Creatinine concentrations were positively and significantly (P < .001) associated with urinary SIDs values, adjusted for pH levels. Urinary simplified strong ion difference values were inversely and significantly (P < .001) related to pH levels.
In critically ill patients with metabolic acidosis, impaired renal function was associated with greater urinary SIDs. Subsequently, the higher urinary SIDs values were related to lower pH levels, illustrating the importance of renal chloride excretion to correct for acidosis.
尿氯排泄可纠正代谢性酸中毒，但在肾功能受损的患者中可能会受到阻碍。我们使用 Stewart 方法探讨了肾功能对代谢性酸中毒危重症患者酸碱特性和尿强离子排泄的影响。
我们检测了 65 例代谢性酸中毒（混合内科和外科）危重症患者的血浆和尿液化学。计算了表观强离子差、有效强离子差、强离子隙和尿简化强离子差（尿 SID）。使用线性回归分析（1）评估血肌酐浓度是否与尿 SID 值相关，校正 pH 值；（2）确定尿 SID 值是否与 pH 值相关。
肌酐浓度与 pH 值校正后的尿 SID 值呈正相关（P <.001）。尿简化强离子差与 pH 值呈负相关（P <.001）。
在代谢性酸中毒的危重症患者中，肾功能受损与更高的尿 SID 相关。随后，更高的尿 SID 值与更低的 pH 值相关，表明肾脏氯排泄对纠正酸中毒的重要性。
