Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale Multi-Sites (LBMMS), Hospices Civils de Lyon (HCL), Lyon, France.
Grand Rounds Software, LLC, Bryn Mawr, Pennsylvania.
Am J Perinatol. 2024 Aug;41(11):1521-1531. doi: 10.1055/s-0043-1772228. Epub 2023 Aug 14.
In studies of concomitant arterial-venous umbilical cord blood gases (CAV-UBGs), approximately 10% of technically valid samples have very similar pH and/or pCO values and were probably drawn from the same type of blood vessel. Without a way to objectively determine the source in these cases, it has been argued that most of these same-source CAV-UBGs are venous because the vein is larger and more easily sampled than the artery. This study aimed to calculate the probability of an arterial (ProbAS) or venous source (ProbVS) of same-source CAV-UBGs in the clinically and medicolegally important pH range of 6.70 to 7.25 using a statistical predictive model based on the cord blood gas values.
Starting with a dataset of 56,703 CAV-UBGs, the ProbAS, ProbVS, and respective 95% confidence intervals (CIs) were calculated for the 241 sample pairs with near-identical pH, pCO, and pO values and a pH of 6.70 to 7.25. Using a previously validated generalized additive model, the source was categorized as: Probable Arterial or Highly Probable Arterial if the ProbAS and CIs were >0.5 or >0.8, respectively; Probable Venous or Highly Probable Venous if the ProbVS and CIs were >0.5 or >0.8, respectively; or Indeterminant if the CIs encompassed ProbAS/VS = 0.5.
A total of 39% of the same-source CAV-UBGs were Probable Arterial, 56% were Probable Venous, and 5% were Indeterminant. However, considering samples with a pH ≤7.19, 80% were Probable Arterial and 16% were Probable Venous. Considering the Highly Probable categories, the more acidemic specimens were 9 times more likely to be arterial than venous. Similarly, CAV-UBGs with pCO > 8.2 kPa (62 mm Hg) or pO ≤ 1.9 kPa (14 mm Hg) were more likely to be in the arterial rather than the venous categories.
Same-source CAV-UBGs in the more acidemic, hypercarbic, or hypoxemic ranges are more likely to be arterial than venous.
· Umbilical cord arterial/venous gases (CAV-UBGs) with similar values are thought to be mainly venous.. · A validated statistical model was used to predict the probability an arterial or venous source.. · CAV-UBGs with very similar values and pH > 7.19 are likely venous; however, those with pH ≤ 7.19 and/or pCO2 > 8.2 kPa and/or pO2 ≤1.9 kPa are more likely arterial..
在研究同时存在的动脉-静脉脐带血气（CAV-UBG）时，约有 10%的技术上有效的样本具有非常相似的 pH 值和/或 pCO 值，并且可能来自同一类型的血管。在这些情况下，由于静脉较大且更容易取样，因此没有一种客观的方法来确定其来源，因此有人认为，这些相同来源的 CAV-UBG 大多数是静脉的。本研究旨在使用基于脐带血气值的统计预测模型，计算在临床上和医学法律上重要的 pH 值为 6.70 至 7.25 的相同来源的 CAV-UBG 的动脉（ProbAS）或静脉来源（ProbVS）的概率。
从 56703 例 CAV-UBG 数据集中，计算了 pH 值为 6.70 至 7.25 的 241 对具有相近 pH 值、pCO 和 pO 值且 pH 值相近的样本对的 ProbAS、ProbVS 及其各自的 95%置信区间（CI）。使用先前验证的广义加性模型，将来源分类为：如果 ProbAS 和 CIs 分别大于 0.5 或大于 0.8，则为“可能动脉”或“高度可能动脉”；如果 ProbVS 和 CIs 分别大于 0.5 或大于 0.8，则为“可能静脉”或“高度可能静脉”；如果 CIs 包含 ProbAS/VS = 0.5，则为“不确定”。
共有 39%的相同来源的 CAV-UBG 为“可能动脉”，56%为“可能静脉”，5%为“不确定”。然而，如果考虑 pH 值≤7.19 的样本，80%为“可能动脉”，16%为“可能静脉”。如果考虑“高度可能”类别，酸性更强的样本成为动脉的可能性是静脉的 9 倍。同样，pCO 值>8.2 kPa（62 mmHg）或 pO 值≤1.9 kPa（14 mmHg）的 CAV-UBG 更可能位于动脉类别而不是静脉类别。
在更酸性、高碳酸血症或低氧血症范围内的相同来源的 CAV-UBG 更可能是动脉而不是静脉。
·具有相似值的脐带动脉/静脉血气（CAV-UBG）被认为主要是静脉的。·使用经过验证的统计模型来预测动脉或静脉来源的概率。·具有非常相似的值和 pH 值>7.19 的 CAV-UBG 可能是静脉的；然而，那些 pH 值≤7.19 且/或 pCO2>8.2 kPa 和/或 pO2≤1.9 kPa 的 CAV-UBG 更可能是动脉的。
