Robin Emmanuel, Futier Emmanuel, Pires Oscar, Fleyfel Maher, Tavernier Benoit, Lebuffe Gilles, Vallet Benoit
Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Lille, Lille, France.
Department of Anaesthesiology and Intensive Care Medicine, Hospital Estaing, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France.
Crit Care. 2015 May 13;19(1):227. doi: 10.1186/s13054-015-0917-6.
The purpose of this study was to evaluate the clinical relevance of high values of central venous-to-arterial carbon dioxide difference (PCO2 gap) in high-risk surgical patients admitted to a postoperative ICU. We hypothesized that PCO2 gap could serve as a useful tool to identify patients still requiring hemodynamic optimization at ICU admission.
One hundred and fifteen patients were included in this prospective single-center observational study during a 1-year period. High-risk surgical inclusion criteria were adapted from Schoemaker and colleagues. Demographic and biological data, PCO2 gap, central venous oxygen saturation, lactate level and postoperative complications were recorded for all patients at ICU admission, and 6 hours and 12 hours after admission.
A total of 78 (68%) patients developed postoperative complications, of whom 54 (47%) developed organ failure. From admission to 12 hours after admission, there was a significant difference in mean PCO2 gap (8.7 ± 2.8 mmHg versus 5.1 ± 2.6 mmHg; P = 0.001) and median lactate values (1.54 (1.1-3.2) mmol/l versus 1.06 (0.8-1.8) mmol/l; P = 0.003) between patients who developed postoperative complications and those who did not. These differences were maximal at admission to the ICU. At ICU admission, the area under the receiver operating characteristic curve for occurrence of postoperative complications was 0.86 for the PCO2 gap compared to Sequential Organ Failure Assessment score (0.82), Simplified Acute Physiology Score II score (0.67), and lactate level (0.67). The threshold value for PCO2 gap was 5.8 mmHg. Multivariate analysis showed that only a high PCO2 gap and a high Sequential Organ Failure Assessment score were independently associated with the occurrence of postoperative complications. A high PCO2 gap (≥6 mmHg) was associated with more organ failure, an increase in duration of mechanical ventilation and length of hospital stay.
A high PCO2 gap at admission in the postoperative ICU was significantly associated with increased postoperative complications in high-risk surgical patients. If the increase in PCO2 gap is secondary to tissue hypoperfusion then the PCO2 gap might be a useful tool complementary to central venous oxygen saturation as a therapeutic target.
本研究旨在评估入住术后重症监护病房（ICU）的高危手术患者中心静脉血与动脉血二氧化碳分压差（PCO2差值）升高的临床意义。我们假设PCO2差值可作为一种有用的工具，用于识别入住ICU时仍需进行血流动力学优化的患者。
在1年期间，本前瞻性单中心观察性研究纳入了115例患者。高危手术纳入标准参照了舒梅克及其同事的标准。记录所有患者入住ICU时、入住后6小时和12小时的人口统计学和生物学数据、PCO2差值、中心静脉血氧饱和度、乳酸水平及术后并发症情况。
共有78例（68%）患者发生术后并发症，其中54例（47%）发生器官功能衰竭。从入住到入住后12小时，发生术后并发症的患者与未发生并发症的患者相比，平均PCO2差值（8.7±2.8 mmHg对5.1±2.6 mmHg；P=0.001）和乳酸中位数（1.54（1.1 - 3.2）mmol/L对1.06（0.8 - 1.8）mmol/L；P=0.003）存在显著差异。这些差异在入住ICU时最大。入住ICU时，PCO2差值预测术后并发症发生的受试者工作特征曲线下面积为0.86，而序贯器官衰竭评估评分（0.82）、简化急性生理学评分II（0.67）和乳酸水平（0.67）。PCO2差值的阈值为5.8 mmHg。多因素分析显示，只有高PCO2差值和高序贯器官衰竭评估评分与术后并发症的发生独立相关。高PCO2差值（≥6 mmHg）与更多器官功能衰竭、机械通气时间延长和住院时间延长相关。
术后ICU入住时PCO2差值升高与高危手术患者术后并发症增加显著相关。如果PCO2差值升高继发于组织灌注不足，那么PCO2差值可能是一种有用的工具，可作为中心静脉血氧饱和度的补充治疗靶点。
