Decreased inferior vena cava diameter as an early marker in postpartum hemorrhage

Abstract

Objectives 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). Methods 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. Results 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). Conclusions 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.

The Role of Ultrasonographic Inferior Vena Cava Measurement in the Volume‐Based Classification of Patients With Hyponatremia

“…The absence of methods that directly measure body volume status, with the paramount importance to accurately assess volume status in patients presenting to ED, necessitated the development of indirect measurement methods; such as the dilution techniques for the body fluids assessment, energy X‐ray absorptiometry, underwater weighing, air displacement plethysmography, bioelectrical impedance analysis, magnetic resonance, and computed tomography 19,20 . Although there is a growing need of a noninvasive tool to accomplish correct fluid management, the available methods are still nonoptimal, expensive and require long procedures and highly specialized personnel, so less invasive techniques such as respiratory CI of IVC with its' prompt identification of intravascular volume in critically ill patient especially in ED has been implemented in clinical use 10,21–26 …”

Correlation between pleth variability index and ultrasonic inferior vena cava-collapsibility index in parturients with twin pregnancies undergoing cesarean section under spinal anesthesia

“…It has been shown that the IVC collapse index decreases with increasing weeks of gestation [(40.8 ± 15.2)% at < 14 weeks of gestation, (32.6 ± 19.9)% at 20-28 weeks, and (26.5 ± 11.8%) at 28-34 weeks], with a rebound [(32.2 ± 19.9)%] by full term (> 27 weeks), with a significant difference (F = 3.557, P = 0.017), with < 14 weeks of gestation significantly higher than 28-34 weeks (P = 0.009) [11,12]. PVI is effective in determining changes in blood volume after general anesthesia combined with epidural block and has recently been used successfully in some studies to assess volume status in spontaneously breathing women [11,12]. The limitations of this study may lie in the fact that intraoperative PVI does not reflect maternal volume status because of the unstable tidal volume and surgical maneuvers during spontaneous breathing.…”

“…The Masimo ® Radical 7 (SET ® sensor) used in this study is more stable than the Masimo ® Radical 5 used in other studies, minimizing interference from autonomic respiratory variability. We believe that the combination of the PVI with the US measurement of the IVC-CI provides better sensitivity and enhanced specificity as a clinically valuable predictor of maternal volume in twin pregnancies [11,12]. Previous editions of the relevant guidelines recommended maternal measurement in the left lateral position and at end-expiration, with the latest version recommending the supine position, but due to the greater impact of the enlarged uterus on IVC reflux compression in the supine position in women with twin pregnancies, we have adopted a 15° left lateral position to reduce the impact on IVC [13].…”

New acoustic window for assessing the inferior vena cava collapsibility in humans in the prone position

“…Hypovolemia is detected if the IVC IC is more than 50%. Traditionally, to visualize IVC, ultrasound probe is placed over the subxiphoid area (2)(3)(4)(5). Changes in the anterior-posterior IVC dimension is used to calculate the IC.…”

“…Ultrasound assessment of inferior vena cava (IVC) collapsibility is performed to determine the volume status of spontaneously breathing and not mechanically ventilated critically ill patients. Conventional assessment is performed in patients in the supine position (1)(2)(3)(4)(5). In this case, a low-frequency ultrasound probe is placed over the subxiphoid area to visualize IVC where it enters the right atrium in a longitudinal section in B-mode.…”