Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Buenos Aires, Argentina.
Crit Care Resusc. 2010 Dec;12(4):248-54.
The correct renal response to metabolic acidosis should be a negative shift in the urinary strong ion difference (SID = Na(+) + K(+) - Cl(-)). Our hypothesis was that the failure to decrease the SID is frequently present and leads to a more severe metabolic acidosis.
DESIGN, SETTING AND PARTICIPANTS: Prospective observational study conducted in the medical/surgical intensive care unit of a teaching hospital between 1 January 2006 and 30 April 2007. Participants were 98 patients with metabolic acidosis on ICU admission and 10 healthy volunteers.
None.
Severity of metabolic acidosis; behaviour of acid-base variables according to positive or negative SID.
Twelve patients (12%) had negative SID and 86 (88%) had positive SID. Compared with patients with positive SID, those with negative SID had higher [HCO(3) (-)] (20 ±2 v 18 ±3 mmol/L), base excess ([BE]) (-5 ±2 v -7 ±2 mmol/L), anion gap ([AG]) (21 ±5 v 17 ±4 mmol/L), Δ[AG] - Δ[HCO(3)(-)] (1 ±5 v -3 ±3 mmol/L) and lower [Cl(-)] (105 ±5 v 111 ±3 mmol/L).
Most of the critically ill patients with metabolic acidosis showed inappropriate renal compensation, as evidenced by positive SID and higher plasma [Cl(-)]. These patients had more severe metabolic acidosis. On the other hand, patients with adequate renal response and negative SID had positive Δ[AG] - Δ[HCO(3)(-)]. These findings, usually considered as a diagnosis of associated metabolic alkalosis, might be interpreted as the proper renal response to metabolic acidosis.
代谢性酸中毒时正确的肾脏反应应该是尿强离子差（SID = Na(+) + K(+) - Cl(-)）的负向偏移。我们的假设是，尿强离子差（SID）不降低的情况经常出现，并导致更严重的代谢性酸中毒。
设计、地点和参与者：前瞻性观察性研究，于 2006 年 1 月 1 日至 2007 年 4 月 30 日在教学医院的内科/外科重症监护病房进行。参与者为入院时患有代谢性酸中毒的 98 名 ICU 患者和 10 名健康志愿者。
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代谢性酸中毒的严重程度；根据尿强离子差（SID）的正负情况，观察酸碱变量的变化。
12 名患者（12%）的尿强离子差（SID）为负，86 名患者（88%）为正。与尿强离子差（SID为正的患者相比，尿强离子差（SID为负的患者）的[HCO3(-)]（20 ±2 v 18 ±3 mmol/L）、碱剩余（[BE]）（-5 ±2 v -7 ±2 mmol/L）、阴离子间隙（[AG]）（21 ±5 v 17 ±4 mmol/L）、Δ[AG] - Δ[HCO3(-)]（1 ±5 v -3 ±3 mmol/L）和[Cl(-)]（105 ±5 v 111 ±3 mmol/L）更低。
大多数患有代谢性酸中毒的重症患者表现出不适当的肾脏代偿，这表现在尿强离子差（SID为正）和更高的血浆[Cl(-)]上。这些患者的代谢性酸中毒更严重。另一方面，有适当肾脏反应和尿强离子差（SID为负的患者）有阳性的Δ[AG] - Δ[HCO3(-)]。这些发现通常被认为是合并代谢性碱中毒的诊断，但也可能被解释为代谢性酸中毒的适当肾脏反应。
