Massalha M, Faranish R, Romano S, Salim R
Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
Ultrasound Unit, Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
Ultrasound Obstet Gynecol. 2022 Feb;59(2):234-240. doi: 10.1002/uog.23695. Epub 2022 Jan 18.
To examine the association between inferior vena cava (IVC) diameter and postpartum blood loss and assess whether IVC diameter is a useful marker in the evaluation of intravascular volume status in women with postpartum hemorrhage (PPH).
This was a prospective case-control study conducted in a university medical teaching center in Afula, Israel, between November 2018 and March 2020. The study cohort consisted of women with a singleton pregnancy who delivered vaginally at term. The PPH group included women diagnosed with PPH based on visually estimated blood loss of 1000 mL or more at the time of enrolment. Hemodynamically unstable women or women with major bleeding at the time of diagnosis were not included. The control group consisted of women with an uneventful fourth stage of labor. IVC diameter was measured using transabdominal ultrasonography during inspiration (IVCi diameter) and expiration (IVCe diameter), and the collapsibility index was calculated ((IVCe - IVCi)/IVCe × 100). The primary outcome was the percentage difference in IVC diameter and collapsibility index between the PPH group and controls. The performance of the IVC collapsibility index in the prediction of the need for blood transfusion in women with PPH was assessed. In order to demonstrate a difference of 20% with a power of 80% and alpha of 0.05, 108 women, at a ratio of 1:2 in the study and control groups, respectively, were needed.
Overall, 36 and 72 women were included in the final analysis in the PPH and control groups, respectively. IVCi and IVCe diameters were significantly smaller in the PPH group (0.93 ± 0.30 cm and 1.26 ± 0.32 cm, respectively) than in controls (1.42 ± 0.31 cm and 1.75 ± 0.28 cm, respectively) (P = 0.001 for both). The percentage reductions in IVCi and IVCe diameters in the PPH group compared with controls were 35.0% and 28.0%, respectively. IVC collapsibility index was increased significantly, by 42.9% (26.04 ± 8.67% vs 18.15 ± 5.07%; P = 0.001) in the PPH group compared with controls. IVC collapsibility index was a significant predictor of the need for blood transfusion and correctly predicted 81% of cases. Logistic regression analysis demonstrated that IVC collapsibility index was also a significant predictor of a drop in hemoglobin level of ≥ 2 g/dL (P = 0.001).
IVC diameter changes in response to postpartum blood loss. Measurement of IVC diameter using transabdominal ultrasonography is an objective and useful non-invasive method for the early evaluation of intravascular volume status in women with PPH and for the prediction of cases that might require blood transfusion. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.
探讨下腔静脉（IVC）直径与产后出血之间的关联，并评估IVC直径是否为评估产后出血（PPH）女性血管内容量状态的有用指标。
这是一项前瞻性病例对照研究，于2018年11月至2020年3月在以色列阿富拉的一所大学医学教学中心进行。研究队列包括足月阴道分娩的单胎妊娠女性。PPH组包括根据入组时目测估计失血量为1000 mL或更多而诊断为PPH的女性。血流动力学不稳定的女性或诊断时大出血的女性未纳入。对照组由产程第四阶段无异常的女性组成。使用经腹超声在吸气时（IVCi直径）和呼气时（IVCe直径）测量IVC直径，并计算塌陷指数（(IVCe - IVCi)/IVCe×100）。主要结局是PPH组与对照组之间IVC直径和塌陷指数的百分比差异。评估IVC塌陷指数在预测PPH女性输血需求方面的表现。为了在80%的检验效能和0.05的α水平下显示20%的差异，研究组和对照组分别需要108名女性，比例为1:2。
总体而言，PPH组和对照组分别有36名和72名女性纳入最终分析。PPH组的IVCi和IVCe直径（分别为0.93±0.30 cm和1.26±0.32 cm）显著小于对照组（分别为1.42±0.31 cm和1.75±0.28 cm）（两者P均=0.001）。与对照组相比，PPH组IVCi和IVCe直径的百分比降低分别为35.0%和28.0%。与对照组相比，PPH组的IVC塌陷指数显著增加，增加了42.9%（26.04±8.67%对18.15±5.07%；P=0.001）。IVC塌陷指数是输血需求的显著预测指标，正确预测了81%的病例。逻辑回归分析表明，IVC塌陷指数也是血红蛋白水平下降≥2 g/dL的显著预测指标（P=0.001）。
IVC直径会因产后出血而发生变化。使用经腹超声测量IVC直径是一种客观且有用的非侵入性方法，可用于早期评估PPH女性的血管内容量状态以及预测可能需要输血的病例。©2021国际妇产科超声学会。
