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Year : 2020  |  Volume : 33  |  Issue : 4  |  Page : 1304-1308

Correlation of inferior vena cava diameter and collapsibility index with central venous pressure in shocked patients

1 Department of General Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Radiology, Department of General Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Department of Emergency Medicine Unit, Department of General Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt

Date of Submission13-Mar-2020
Date of Decision12-Jun-2020
Date of Acceptance15-Jun-2020
Date of Web Publication24-Dec-2020

Correspondence Address:
Mahmoud T. A. H. Toulan
Sheimyates, El Shohadaa 32843
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mmj.mmj_65_20

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The aim was to determine the correlation of the caval index, inferior vena cava (IVC) diameter, and central venous pressure (CVP) in shocked patients in the emergency room.
Assessment of intravascular volume is important in shocked patients. It can be measured through many techniques, among those include CVP, collapsibility index, and diameter of IVC.
Patients and methods
This was a prospective and cross-sectional study and included 100 patients treated at the Emergency Department of Menoufia University Hospital. They were selected according to certain inclusion and exclusion criteria with already inserted central venous catheter and were measured for CVP, and concomitantly the IVC diameter was measured with ultrasound using M-mode to measure the expiratory and inspiratory diameter and collapsibility index of the IVC, and then the patients were divided into three groups according to the CVP, with CVP less than 10, CVP 10–15 and CVP more than 15.
Among the 100 patients enrolled, the median age was 56.01 ± 20.92 years. The correlation of the CVP measurement with the ultrasound IVC caval index was r= −0.911 (P < 0.001), with the expiratory IVC diameter was r = 0.703 (P < 0.001), and with the inspiratory IVC diameter was r = 0.875 (P < 0.001). The sensitivity and specificity of the caval index showed that the cutoff points were 50, 40, and 20 at CVP levels 10, 10–15, and 15 cm H2 O, respectively.
This study found that in shocked patients there is a good correlation between CVP and collapsibility index, as well as with inspiratory and expiratory diameter of IVC.

Keywords: central venous pressure, collapsibility index, inferior vena cava diameter, shock

How to cite this article:
Mohammed MA, Hagag MG, Mousa WA, Toulan MT. Correlation of inferior vena cava diameter and collapsibility index with central venous pressure in shocked patients. Menoufia Med J 2020;33:1304-8

How to cite this URL:
Mohammed MA, Hagag MG, Mousa WA, Toulan MT. Correlation of inferior vena cava diameter and collapsibility index with central venous pressure in shocked patients. Menoufia Med J [serial online] 2020 [cited 2021 Apr 19];33:1304-8. Available from: http://www.mmj.eg.net/text.asp?2020/33/4/1304/304512

  Introduction Top

Shock is a popular emergency problem, and right fluid resuscitation in the emergency room is crucial in shocked patients[1]. Early assessment of a critical patient's volume status is very important in the emergency department for management. Various methods of assessment have been described, but still no single gold standard measure has been proven to exist[2]. Although central venous pressure (CVP) has been proven to be nondependable, it is still used in the emergency departments around the world[3]. There are many complications related to central venous catheter (CVC) insertion, including failure to place the catheter, subcutaneous hematoma, CVC-associated infection, arterial puncture, pneumothorax, and hemothorax[4]. The evaluation of the inferior vena cava (IVC) diameter and its changes with respiratory cycle by ultrasound has been used to assess the volume status of a patient, and it can be used as a substitute to CVC. It is a dynamic measurement of volume status, as it shows the volume changes that happen with expiration and inspiration[5]. The IVC diameter changes depending on the phase of respiration. During inspiration, the IVC diameter decreases and vice versa during expiration. The measure of this is called the IVC collapsibility index (IVC-CI) given by (IVC expiratory diameter − IVC inspiratory diameter)/IVC expiratory diameter[6].

The aim of this study was to determine the correlation between both IVC diameter and IVC collapsibility index and central venous pressure in shocked patients.

  Patients and Methods Top

This was a prospective, cross-sectional study. It included 100 patients in the Emergency Department of Menoufia University Hospital after approval of the Local Ethics Committee, and it was carried out during the period from January 2018 to September 2019. The study used a one-time assessment of the IVC diameter and IVC collapsibility index to determine any correlation with CVP measured by central venous catheter. All the patients were evaluated according to the following criteria: inclusion criteria were adult patients (18 years or older), patients who have signs of shock, both sexes, spontaneously breathing patients, and patients who have CVC (subclavian or internal jugular vein) in place, and exclusion criteria were patients younger than 18 years, patients with severe orthopnea or who are unable to lie supine, mechanically ventilated patients, any patient who was not suitable for bedside ultrasonography, which was used to measure the IVC, such as morbidly obese patients or when ultrasonography was limited by dilated bowel loops, patients who refused to participate, patients with increased intra-abdominal pressure like in pregnancy, or patients with moderate to massive amount of ascites or abdominal compartmental syndrome.

All patients in the emergency department and medical intensive care unit who had already been fitted with a CVC for CVP monitoring according to their clinical indications were assessed for eligibility. Their demographic and basic clinical data including primary illness; vital data like blood pressure, heart rate, respiratory rate, Glasgow coma scale, and urine output; and laboratory data, including arterial blood gases, ScvO2, base excess, and lactate level were recorded. All the ultrasonographic examinations were performed with the patients in supine position by the same physician throughout the present study using a portable ultrasonography unit, and anteroposterior diameter of inferior vena cava (IVCD) was measured in duplicate, using frozen images which were obtained by M mode of ultrasound at end of inspiration (iIVCD) and end of expiration (eIVCD) in a subxiphoid location in the longitudinal axis 2 cm distal to the IVC-hepatic vein junction where the anterior and posterior wall of the IVC are easily visualized and lie parallel to each other using ultrasound machine (Aloka SSD-1200CV Ultrasound Machine; Aloka, Tokyo, Japan) with convex (3.5–5 MHz) transducer. The IVC collapsibility index (IVC-CI), which is a widely used parameter in IVC assessment of intravascular volume, was determined as the percentage of the difference between eIVCD and iIVCD divided by the eIVCD as expressed by the following equation: IVC-CI = [(eIVCD−iIVCD)/eIVCD] × 100. The CVP was also measured in the supine position and was measured manually using a manometer at midaxillary level with patient lying supine. The IVC diameter assessment and CVP measurements were recorded concomitantly.Then the patients were divided into three groups according to their CVP into group A (CVP <10)[NO = 40], group B (CVP10–15)[No = 15], and group C (CVP >15)[No = 45].

Statistical analysis

The data were collected, tabulated, and analyzed by SPSS (Statistical Package for the Social Sciences) version 17.0 (SPSS Inc., IBM, Chicago, Illinois, USA) on IBM compatible computer (IBM). Two types of statistics were done: descriptive statistics (e.g., percentage, mean, and SD) and analytic statistics, which included the following tests: χ2 test, Kruskal–Wallis test, and analysis of variance test. Pearson correlation coefficient was used to assess the correlation. A P value less than 0.05 was considered to be significant.

  Results Top

This study involved 100 patients. Among them, 34 patients were diagnosed with septic shock, 25 with hypovolemic shock, 27 with cardiogenic shock, six with neurogenic shock, six with obstructive shock, and six with anaphylactic shock.

The mean ± SD age (of the study group was 56.01 ± 20.92 years, with the age ranged from 18 to 90 years. Overall, 54% (n = 54) were male and 46% (n = 46) were female, with the mean ± SD body mass index of 26.44 ± 4.65. Regarding past medical history, 75% of the patients had a past medical history, whereas 25% did have not [Table 1]. Regarding clinical data of the study group, mean ± SD respiratory rate was 30.42 ± 5.30, mean ± SD heart rate was 109.60 ± 21.17, mean ± SD systolic blood pressure mean was 76 ± 8.96, whereas mean ± SD diastolic blood pressure was 47.65 ± 7.60, and the mean ± SD arterial pressure was 56.75 ± 7.43. Regarding Glasgow coma scale, the mean ± SD was 14.22 ± 1.07. Mean ± SD urine output was 0.418 ± 0.203 ml/kg/h. Regarding laboratory data, mean ± SD PH was 7.25 ± 0.104, mean ± SD HCO3 (mmol/l) was 14.01 ± 3, mean ± SD base excess (mmol/l) was − 11.49 ± 5.700, mean ± SD ScVO2(%) was 64.79 ± 11, and mean ± SD lactate (mmol/l) was 7.62 ± 2 [Table 2]. The mean ± SD central venous pressure was 13.70 ± 9.55, which ranged from − 2 to 30 cmH2 O, whereas the mean ± SD IVC expiratory diameter, inspiratory diameter, and collapsibility index were 18.58 ± 5.50, 12.31 ± 7.29, and 38.27 ± 24.93, respectively, and both diameters showed high correlation with CVP, with P value less than 0.001 [Table 3]. Moreover, there was a high correlation between the CVP and collapsibility index [Figure 1]. Then the patients were divided into 3 groups according to the CVP as follows: group A (CVP <10), group B (CVP10–15), and group C (CVP >15), which showed a statistically significant correlation between CVP and IVC expiratory diameter, inspiratory diameter, and collapsibility index, with P value less than 0.001, and between the CVP and the type of shock, with P value less than 0.001 [Table 4]. The sensitivity and specificity of the caval index were calculated to predict the CVP. The results showed that the cutoff points of the caval index at CVP of less than 10 cm H2 O correlated with a caval index of 50 (sensitivity 30 and specificity 91) and at CVP of 10–15 cm H2 O correlated with a caval index of 40 (sensitivity 53 and specificity 90) whereas at CVP of more than 15 cm H2 O correlated with a caval index of 20 (sensitivity 40, specificity 96) [Table 5].
Figure 1: The correlation between central venous pressure and inferior vena cava collapsibility index.

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Table 1: Illustrating the demographic data and medical history of the studied patients

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Table 2: Clinical and laboratory data of the studied patients

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Table 3: Inferior vena cava diameters and collapsibility index and their correlation with the central venous pressure in the studied patients

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Table 4: Demographic, clinical, and laboratory data and their comparison among group A (CVP<10), group B (CVP 10-15), and group C (CVP>15)

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Table 5: Sensitivity and specificity of the caval index in group A (CVP<10), group B (CVP 10-15), and group C (CVP>15)

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  Discussion Top

Assessing intravascular volume is crucial for the improvement of the patients, especially the shocked ones during hospital care. There are many techniques in measuring volume status, such as ultrasound assessment of IVC diameter and collapsibility index and measuring CVP; each method has its own pros and cons[7]. However, CVP is not a true reflection of preload, and there are limitations regarding using CVP as it is invasive, expensive, and time consuming[8]. Ultrasound has many applications in the emergency departments nowadays, as it is used in several aspects in the EDs especially in shocked and traumatized patients, like focused assessment with sonography for trauma, as it can facilitate a timely diagnosis for patients with blunt abdominal trauma[9] as a detection method for hemorrhage, which is the most common preventable cause of early death after trauma[10], and the RUSH (Rapid Ultrasound in Shock) protocol, which is used for early detection and treatment of shock in EDs. The RUSH protocol is evaluated at three important steps: the pump (heart), the tank (IVC), and the pipes (aorta)[11]. So assessment of intravascular volume by measuring the IVC-CI and Diameter using bedside ultrasonography has many advantages, as it is safe, noninvasive, portable, and faster assessment than inserting CVC in measuring fluid status[12]. We found that CVP strongly correlated with IVC-CI. Thanakitcharu et al.[8] also found a significant correlation between the CVP and IVC-CI. This result is also in accordance with study performed by Stawicki et al.[13], as they found that measurements of IVC-CI best correlated with CVP in the setting of low (≤20%) and high (≥60%) collapsibility ranges. On the contrary, Govender et al.[14] found that there is no association between CVP and IVC-CI, and there was a weak negative correlation between CVP and IVC-CI. In our study, there was a significant correlation of the IVC expiratory and inspiratory diameter with the CVP. Khalil et al.[15] found that CVP correlated well with expiratory IVC diameter and with inspiratory IVC diameter, and Ilyas et al.[16] found a strong positive correlation between the CVP and the expiratory IVC diameter and the inspiratory IVC diameter. However, Wiryana et al.[17] found that there was a weak correlation between CVP and maximum IVC diameter. In our study, the cutoff points of the caval index were 50, 40, and 20 at CVP levels of less than 10 cm H2 O, 10–15 H2 O, and more than 15 cm H2 O, respectively, which is higher in relation to a study by Worapratya et al.[1], and it was similar to the studies by Muhammad et al.[18] and Rudski et al.[19].

  Conclusion Top

In shocked patients, we found that central venous pressure correlates well with inferior vena cava expiratory, inspiratory diameter, and collapsibility index.


The study was not a double-blinded study and was conducted in a single center.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Thanakitcharu P, Charoenwut M, Siriwiwatanakul N. Inferior vena cava diameter and collapsibility index: a practical non-invasive evaluation of intravascular fluid volume in critically-ill patients. J Med Assoc Thai 2013; 96(Suppl 3):S14–S22.  Back to cited text no. 8
Zieneldin A, Rageh T, Azab S, Elgndy N. Positive focused assessment sonography as an indication for laparotomy in hemodynamically unstable blunt traumatized patient. Menoufia Med J 2017; 30:400–404.  Back to cited text no. 9
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Seif D, Perera P, Mailhot T, Rileyand D, Mandavia D. Bedside ultrasound in resuscitation and the rapid ultrasound in shock protocol. Crit Care Res Pract 2012; 2012:503254.  Back to cited text no. 11
Maecken T, Grau T. Ultrasound imaging in vascular access. Crit Care Med 2007; 35 (5 Suppl):S178–S185.  Back to cited text no. 12
Stawicki SP, Braslow BM, Panebianco NL, Kirkpatrick JN, Gracias VH, Hayden GE, et al. Intensivist use of hand-carried ultrasonography to measure IVC collapsibility in estimating intravascular volume status: correlations with CVP. J Am Coll Surg 2009; 209:55–61.  Back to cited text no. 13
Govender J, Postma I, Wood D, Sibanda W. Is there an association between central venous pressure measurement and ultrasound assessment of the inferior vena cava? Afr J Emerg Med 2018; 8:106–109.  Back to cited text no. 14
Khalil A, Khan A, Hayat A. Correlation of inferior vena cava (IVC) diameter and central venous pressure (CVP) for fluid monitoring in ICU. Pak Armed Forces Med J 2015; 65:235–238.  Back to cited text no. 15
Ilyas A, Ishtiaq W, Assad S, Ghazanfar H, Mansoor S, Haris M, et al. Correlation of IVC diameter and collapsibility index with central venous pressure in the assessment of intravascular volume in critically ill patients. Cureus 2017; 9:e1025.  Back to cited text no. 16
Wiryana M, Sinardja K, Aryabiantara W, Senapathi T, Widnyana M, Aribawa G, et al. Central venous pressure correlates with inferior vena cava collapsibility index in patients treated in intensive care unit. Bali J Anesthesiol 2017; 1:7–9.  Back to cited text no. 17
Muhammad N, Azlan N, Safferi R, Robertson C. Internal jugular vein height and inferior vena cava diameter measurement using ultrasound to determine central venous pressure: a correlation study. Med J Malaysia 2015; 70:63–66.  Back to cited text no. 18
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher M, Chandrasekaran K, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr 2010; 23:685–713. quiz 786  Back to cited text no. 19


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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