Emergency Medicine, Westmead Hospital, Westmead, New South Wales, Australia
Discipline of Emergency Medicine, The University of Sydney Westmead Clinical School, Sydney, New South Wales, Australia.
Emerg Med J. 2021 Sep;38(9):711-717. doi: 10.1136/emermed-2020-209751. Epub 2021 Mar 31.
ABG samples are often obtained in trauma patients to assess shock severity. Venous blood gas (VBG) sampling, which is less invasive, has been widely used to assess other forms of shock. The study aim was to determine the agreement between VBG and ABG measurements in trauma.
Patients were enrolled at an Australian trauma centre between October 2016 and October 2018. Bland-Altman limits of agreement (LOA) between paired blood gas samples taken <30 min apart were used to quantify the extent of agreement. The impact of using only VBG measurements was considered using an a priori plan. Cases where venous sampling failed to detect 'concerning levels' were flagged using evidence-based cut-offs: pH ≤7.2, base deficit (BD) ≤-6, bicarbonate <21 and lactate ≥4. Case summaries of these patients were assessed by independent trauma clinicians as to whether an ABG would change expected management.
During the study period 176 major trauma patients had valid paired blood gas samples available for analysis. The median time difference between paired measurements was 11 min (IQR 6-17). There was a predominance of men (81.8%) and blunt trauma (92.0%). Median Injury Severity Score was 13 (range 1-75) and inpatient mortality was 6.3%. Mean difference (ABG-VBG) and LOA between paired arterial and venous measurements were 0.036 (LOA -0.048 to 0.120) for pH, -1.27 mmol/L (LOA -4.35 to 1.81) for BD, -0.64 mmol/L (LOA -1.86 to 0.57) for lactate and -1.97 mmol/L (LOA -5.49 to 1.55) for bicarbonate. Independent assessment of the VBG 'false negative' cases (n=20) suggested an ABG would change circulatory management in two cases.
In trauma patients VBG and ABG parameters displayed suboptimal agreement. However, in cases flagged as VBG 'false negative' independent review indicated that the availability of an ABG was unlikely to change management.
ABG 样本常用于评估创伤患者的休克严重程度。静脉血气（VBG）采样具有侵袭性较小的特点，已广泛用于评估其他类型的休克。本研究旨在确定创伤患者中 VBG 和 ABG 测量之间的一致性。
2016 年 10 月至 2018 年 10 月期间，在澳大利亚创伤中心招募患者。采用 Bland-Altman 界限（LOA）分析 30 分钟内采集的配对血气样本，以量化一致性程度。根据预先计划，考虑仅使用 VBG 测量的影响。使用基于证据的截断值标记静脉采样未能检测到“关注水平”的情况：pH 值≤7.2、碱剩余（BD）≤-6、碳酸氢盐＜21 和乳酸≥4。由独立的创伤临床医生评估这些患者的病例摘要，以确定 ABG 是否会改变预期的治疗方案。
研究期间，176 例严重创伤患者有可用的配对血气样本进行分析。配对测量的中位时间差为 11 分钟（IQR 6-17）。患者以男性为主（81.8%），钝器伤为主（92.0%）。中位损伤严重程度评分 13 分（范围 1-75 分），住院死亡率 6.3%。动脉与静脉测量的平均差值（ABG-VBG）和 LOA 分别为 pH 值 0.036（LOA -0.048 至 0.120）、BD-1.27mmol/L（LOA -4.35 至 1.81）、乳酸-0.64mmol/L（LOA -1.86 至 0.57）和碳酸氢盐-1.97mmol/L（LOA -5.49 至 1.55）。对 20 例 VBG“假阴性”病例的独立评估表明，在两种情况下 ABG 可能会改变循环管理。
在创伤患者中，VBG 和 ABG 参数显示出较差的一致性。然而，在标记为 VBG“假阴性”的病例中，独立评估表明 ABG 的可用性不太可能改变治疗方案。
