Australian and New Zealand Intensive Care-Research Centre, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital Campus, 75 Commercial Road, Prahran, VIC 31821, Australia.
Crit Care. 2010;14(1):R25. doi: 10.1186/cc8888. Epub 2010 Feb 24.
Higher lactate concentrations within the normal reference range (relative hyperlactatemia) are not considered clinically significant. We tested the hypothesis that relative hyperlactatemia is independently associated with an increased risk of hospital death.
This observational study examined a prospectively obtained intensive care database of 7,155 consecutive critically ill patients admitted to the Intensive Care Units (ICUs) of four Australian university hospitals. We assessed the relationship between ICU admission lactate, maximal lactate and time-weighted lactate levels and hospital outcome in all patients and also in those patients whose lactate concentrations (admission n = 3,964, maximal n = 2,511, and time-weighted n = 4,584) were under 2 mmol.L-1 (i.e. relative hyperlactatemia).
We obtained 172,723 lactate measurements. Higher admission and time-weightedlactate concentration within the reference range was independently associated with increased hospital mortality (admission odds ratio (OR) 2.1, 95% confidence interval (CI) 1.3 to 3.5, P = 0.01; time-weighted OR 3.7, 95% CI 1.9 to 7.00, P < 0.0001). This significant association was first detectable at lactate concentrations > 0.75 mmol.L-1. Furthermore, in patients whose lactate ever exceeded 2 mmol.L-1, higher time-weighted lactate remained strongly associated with higher hospital mortality (OR 4.8, 95% CI 1.8 to 12.4, P < 0.001).
In critically ill patients, relative hyperlactataemia is independently associated with increased hospital mortality. Blood lactate concentrations > 0.75 mmol.L-1 can be used by clinicians to identify patients at higher risk of death. The current reference range for lactate in the critically ill may need to be re-assessed.
正常参考范围内的较高乳酸浓度（相对高乳酸血症）不被认为具有临床意义。我们检验了一个假设，即相对高乳酸血症与住院死亡风险增加独立相关。
这项观察性研究检查了来自澳大利亚四所大学医院的四个重症监护病房（ICU）中连续收治的 7155 例危重症患者的前瞻性获得的 ICU 数据库。我们评估了所有患者入院时、最大时和时间加权时的乳酸浓度与医院结局之间的关系，还评估了那些乳酸浓度（入院时 n=3964，最大时 n=2511，时间加权时 n=4584）低于 2mmol/L（即相对高乳酸血症）的患者的关系。
我们获得了 172723 次乳酸测量值。在参考范围内，较高的入院时和时间加权的乳酸浓度与住院死亡率增加独立相关（入院时比值比（OR）2.1，95%置信区间（CI）1.3 至 3.5，P=0.01；时间加权 OR 3.7，95%CI 1.9 至 7.0，P<0.0001）。这种显著相关性在乳酸浓度>0.75mmol/L 时首次可检测到。此外，在那些乳酸浓度曾经超过 2mmol/L 的患者中，较高的时间加权乳酸浓度仍然与较高的住院死亡率密切相关（OR 4.8，95%CI 1.8 至 12.4，P<0.001）。
在危重症患者中，相对高乳酸血症与住院死亡率增加独立相关。临床医生可以使用血液乳酸浓度>0.75mmol/L 来识别死亡风险较高的患者。目前对危重症患者乳酸的参考范围可能需要重新评估。
