eISSN: 1731-2531
ISSN: 1642-5758
Anaesthesiology Intensive Therapy
Current issue Archive Manuscripts accepted About the journal Supplements Editorial board Reviewers Abstracting and indexing Subscription Contact Instructions for authors Ethical standards and procedures
SCImago Journal & Country Rank

vol. 54
Original paper

Ultrasound imaging and central venous pressure in spontaneously breathing patients: a comparison of ultrasound-based measures of internal jugular vein and inferior vena cava

Nicola Parenti
Luca Bastiani
Cesare Tripolino
Igor Bacchilega

Department of Internal Medicine, Ospedale Maggiore “Carlo Alberto Pizzardi”, Bologna, Italy
Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy
Department of Internal Medicine, “San Giovanni di Dio” Hospital, Crotone, Italy
Department of Anesthesia, “Santa Maria della Scaletta” Hospital, Imola, Italy
Anaesthesiol Intensive Ther 2022; 54, 2: 150–155
Online publish date: 2022/04/13
Article file
- Ultrasound.pdf  [0.16 MB]
Get citation
JabRef, Mendeley
Papers, Reference Manager, RefWorks, Zotero
Central venous pressure (CVP) represents a parameter indicating the mean right atrial pressure. In daily practice, it is measured using a central venous catheter advanced via the internal jugular or subclavian (but also femoral or axillary) veins and placed in the superior vena cava near the right atrium. Normal values range from 3 to 6 mmHg [1]. CVP is usually employed to evaluate the volume status of critical patients [2]. However, invasive CVP measurement is often time-consuming, requires special monitoring equipment and trained personnel, and is burdened by some complications such as local haematoma, accidental arterial puncture, pneumothorax, infection, and venous thrombosis [3].
Point-of-care ultrasound provides a non-invasive, safe, quick, and cheap tool for the evaluation of the volume status in critically ill patients [4]. Ultrasound (US)-measured inferior vena cava (IVC) and internal jugular vein (IJV) diameters have been demonstrated to predict the volume status in venti­lated patients [5–7], but few data are available in spontaneously breathing patients [8–11]. CVP values might be subjected to the influence of heart function and intra-abdominal pressure (IAP) [12]. However, in the studies analysing the association between CVP and US measures of venous filling, information about heart function or IAP values are often lacking.
The present study was designed to investigate the relationship among US indicators of venous filling and invasive CVP in spontaneously breathing patients. IVC diameters, IJV diameters, IVC collapsi­bility index, and IJV ratio were used as ultrasonographic measures of venous filling. At the same time, all subjects underwent echocardiography and intra- abdominal pressure measurement.


Study design

This is an observational cross-sectional study conducted in adult patients attending the Intensive Care Unit of the “Santa Maria della Scaletta” Hospital of Imola (Italy).
Inclusion criteria were as follows: age ≥ 18 years; spontaneously breathing patients; and supine position. Exclusion criteria were as follows: cerebral ischaemia, carotid artery stenosis, or bradycardia.
Written informed consent was obtained from patients or their legal guardians. The hospital’s insti­tutional ethical committee approved the study (Prot. N. 124 CE; Cod. CE: 14111).
Among 56 patients screened for inclusion, 41 were recruited. The main cause of exclusion was the ina­bility to perform all US measures.

Ultrasound examination

The ultrasound study was performed using an echo-Doppler Philips HD 11 XE (Royal Philips Electronics, Netherlands) equipped with a 12–3-MHz linear array, steerable pulsed-wave Doppler, and simultaneous ECG recording. A cardiac probe (1–5 MHz, phased array) was used for IVC imaging and transthoracic echocardiography. A single experienced sonographer, blinded to the CVP measurement, performed the ultrasound examinations. Bedside ultrasound images were obtained with the patient in the supine position.
Vascular ultrasound examinations were performed as previously reported [8–10] (Figure 1). Briefly, IJV was imaged in a transverse plane, 2 cm above the clavicle, at the end of expiration. The anteroposterior diameter (AP-IJV) and transverse dia­meter (T-IJV) were recorded, and then the IJV ratio was calculated as AP-IJV/T-IJV [8]. IVC measurements were registered in a longitudinal plane with a cardiac transducer in the subxiphoid position. The IVC diameter was measured at 3–4 cm from the junction of the IVC and right atrium. B-mode was used to register a cine loop of the IVC over 2 respiratory cycles. Two IVC diameters were measured: the maximum anterior-posterior dimension at the end-expiration (IVCD-max) and the minimum anterior-posterior dimension at the end-inspiration (IVCD-min). These measures allowed us to calculate the IVC collapsibility index as IVCD-max – IVCD-min/IVCD-max × 100.
Echocardiographic imaging was performed by another experienced examiner, blinded to the vascular and CVP measurements. Left ventricular systolic function was calculated as the ejection fraction using volumetric measurements following the biplane method of disks (modified Simpson’s rule) in 2- and 4-chamber views [13]. Right ventricular (RV) systolic function was evaluated as tricuspid annular plane systolic excursion (TAPSE). TAPSE was measured using M-mode in the apical 4-chamber view. The M-mode cursor was positioned parallel to the RV free wall as it meets the tricuspid annulus. A TAPSE measurement < 17 mm is highly specific for RV dysfunction [13].
The CVP waveform from the central venous catheter and a single-lead electrocardiogram rhythm strip was registered a few minutes after the ultrasound examination. The CVP was measured at the end-expiration with the patient in a supine position. At the same time, the intra-abdominal pressure (IAP) was measured using a Foley cathe­ter filled with 250 mL of normal saline in the patient’s bladder. The normal IAP value is 5–10 mmHg. The Simplified Acute Physiology Score II (SAPS II) was also calculated for every individual [14].

Statistical analyses

All the analyses were performed using Stata/SE Statistical Software 13.1 (StataCorp, College Station, Texas, USA). Categorical variables were reported as percentages and all the continuous variables as mean ± standard deviation. The Mann-Whitney test was used to compare variables among the patient groups.
The Pearson or Spearman’s rank correlation coefficients were used, as appropriate, to assess the correlation among IVC diameters, IJV diameters, collapsibility index, and IJV ratio, and CVP.
The receiver operating characteristic (ROC) curves were plotted to compare the specificity and sensitivity of each ultrasound measurement as predictors of a “low” CVP (≤ 8 mmHg). The ROC curves for predicting “high” CVP (> 8 mmHg) were not performed due to the low number of subjects (n = 12). Multivariable linear regression analysis was used to test the independent association between ultrasound-derived indexes and CVP. A P-value < 0.05 was considered statistically significant.


Overall, we collected data from 41 spontaneously breathing patients. The mean age was 75 years (56% male). The median SAPS II score was 38. Sepsis was the most frequent diagnosis at admission.
Median CVP, intra-abdominal pressure, and TAPSE values were 7 mmHg (range 2–20 mmHg), 8 mmHg (range 5–18), and 25 mm (range 15–30 mm), respectively.
The mean intra-abdominal pressure and TAPSE were 9.7 mmHg and 25 mm. A low CVP (< 8 mmHg) was found in 71% (29/41) of cases.
Figures 2 and 3 illustrate the bivariate correlation analyses of each ultrasound measurement with CVP. The results demonstrated a significant correlation between the following: CVP and AP-IJV (r = 0.58, P = 0.0001); CVP and IJV ratio (r = 0.35, P = 0.03); and CVP and IVCD-max (r = 0.35, P = 0.02). Conversely, the IVC collapsibility index was not related with CVP (r = –0.24, P = 0.13).
Differences in clinical and ultrasound parameters between subjects with “low” and “high” CVP are shown in Table 1. The “high” CVP group had significantly lower LVEF, and significantly higher values of AP-IJV and IJV aspect ratio.
The AUROC values of each tested variable for predicting “low” CVP (≤ 8 mmHg) are shown in Table 2. The AP-IJV had an AUC value of 0.79 (95% CI: 0.63–0.91), whereas the IJV ratio (0.68 [95% CI: 0.51–0.82]), IVCD-max (0.66 [95% CI: 0.49–0.80]), and IVC collapsibility index (0.62 [95% CI: 0.45–0.77]) showed lower AUC values.
Furthermore, an AP-IJV value ≤ 7 mm showed the best performance in predicting a CVP < 8 mmHg, with 88% sensitivity and 60% specificity. Collapsi­bility index value > 17, IVCD-max ≤ 2.1 cm, and IJV ratio ≤ 0.63 had moderate sensitivity and specificity in predicting low CVP.
Finally, in multivariable linear regression analysis, only the AP-IJV showed a significant association with CVP: β coefficient = 0.63 (95% CI: 0.30–0.96) with P < 0.001.


The results of the present study demonstrated that AP-IJV, the IJV ratio, and IVCD-max significantly correlated with the invasive CVP, whereas IVC collapsibility index did not show any association. Among them, AP-IJV showed the best correlation with CVP (r = 0.58, P = 0.0001) and good accuracy in predicting low CVP (≤ 8 mmHg), with a sensitivity of 88%, a specificity of 60%, and an AUROC of 0.8.
In the last decades, point-of-care ultrasound has gained increasing popularity because it represents a non-invasive, safe, quick, and cheap tool for the evaluation of volume status in critical patients [5–11]. In particular, some guidelines have proposed the evaluation of intravascular volume status based on sonographic examination of the IVC [4]. In a recent systematic review, it was found that US measurement of IVC diameter and collapsibility represent a valid method for estimating CVP and right atrial pressure [11]. Furthermore, point-of-care ultrasound has proven useful also in paediatric intensive care units because it is radiation free, non-invasive, quick, and can be done at the patient’s bedside [15, 16]. However, the IVC ultrasound assessment is not feasible in the case of obesity, abdominal air interposition, or surgical wounds. For this reason, seve­ral investigations focussed on ultrasound evaluation of the IJV as a surrogate indicator of CVP [17–19].
The first study investigating the application of IJV-US-derived measures in the estimation of volume status date back to 2000. In these pioneering observations, Lipton described the sonographic patterns of IJV in patients with low, normal, and elevated CVP [20]. Later, Donahue et al. [9] explored the correlation between IJV-US measures and CVP in a cohort of 34 non-ventilated ICU patients. The results of this pilot study demonstrated that patients with CVP ≤ 10 cm H2O showed a mean IJV diameter of 7.0 mm, whereas patients with CVP > 10 cm H2O had a mean diameter of 12.5 mm. Furthermore, a strong intra- and interobserver agreement was found, with a correlation coefficient of 0.92 [9]. Similar results were obtained by Keller et al. [10] in a sample of 44 spontaneously breathing patients. The authors demonstrated that the IJV aspect ratio strongly predicted a CVP of 8 mmHg, with an area under the receiver operating characteristic curve of 0.84.
The predictive power of US measurement of IJV was also validated against the right heart catheterization. Indeed, an increase in IJV cross-sectional area > 17% during Valsalva excludes elevated right atrial pressure [21] and predicts 30-day re-hospitalization in patients with acute decompensated heart failure [22].
Of note, few studies have compared the accuracy of US-IJV and US-IVC in predicting CVP [8, 23, 24]. The results of these investigations are varied and often conflicting. In detail, a cross-sectional study comparing 3 point-of-care ultrasounds found that IVC diameter is a stronger predictor of CVP than the IVC collapsibility index or the IJV aspect ratio [8]. On the other hand, Avcil et al. [24] demonstrated that IJV had the best diagnostic performance in estimating CVP when compared with US-IVC measures (IVC-max, IVC-min, IVC collapsibility).
The present study demonstrates that AP-IJV strongly correlated with CVP (r = 0.58, P = 0.0001) in both simple and multivariable linear regression analysis. It also shows sensitivity and specificity comparable with those of previous studies [9, 24]. The original purpose of our investigation was the assessment of right and left systolic cardiac function and intra-abdominal pressure. As is known, all these variables might alter the CVP values. In the present study, patients had normal right ventricular function and normal intra-abdominal pressure. Therefore, the values of tested variables (CVP, IJV, and IVC diameters) were due to the intravascular volume status and not the cardiac dysfunction or elevated intra-abdominal pressure.
The present study has some shortcomings that need to be discussed. First, the small sample of subjects prevents a definite conclusion being drawn about this topic. Second, ultrasound examination is a highly operator-dependent tool, and this makes it difficult to compare the results of different studies. Finally, we employed CVP as a reference method to estimate the volume status of patients. However, it has been demonstrated that dynamic parameters (such as pulse pressure variation, stroke volume variation, passive leg raising, etc.) are better predictors of fluid responsiveness than static parameters (such as CVP and others).


Based on our data, IJV-US might be useful for identifying patients with a low CVP who are likely to benefit from a fluid challenge; conversely, its usefulness for identifying patients with a very high CVP warrants additional investigation.


1. Assistance with the article: Professor Vincenzo Stanghellini, Dr. Gianni Rossi, Dr. Roberto Biscione, Dr. Maria Giovanna Vespignani.
2. Financial support and sponsorship: none.
3. Conflicts of interest: none.


1. Marik PE, Baram M, Vahid B. Does central venous pressure predict fluid responsiveness? A systematic review of the literature and the tale of seven mares. Chest 2008; 134: 172-178. doi: 10.1378/chest.07-2331.
2. Rhodes A, Evans LE, Alhazzani W, et al. surviving sepsis campaign: international guidelines for management of sepsis and septic shock: 2016. Intensive Care Med 2017; 43: 304-377. doi: 10.1007/s00134-017-4683-6.
3. Akmal AH, Hasan M, Mariam A. The incidence of complications of central venous catheters at an intensive care unit. Ann Thorac Med 2007; 2: 61-63. doi: 10.4103/1817-1737.32232.
4. American College of Emergency Physician. Emergency ultrasound guidelines. Ann Emerg Med 2009; 53: 550-570. doi: 10.1016/j.annemergmed. 2008.12.013.
5. Bendjelid K, Romand JA. Fluid responsiveness in mechanically ventilated patients: a review of indices used in intensive care. Intensive Care Med 2003; 29: 352-360. doi: doi.org/10.1007/s00134-002-1615-9.
6. Barbier C, Loubieres Y, Schmit C, et al. Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med 2004; 30: 1740-1746. doi: 10.1007/s00134-004-2259-8.
7. Feissel M, Michard F, Faller JP, et al. The respiratory variation in inferior vena cava diameter as a guide to fluid therapy. Intensive Care Med 2004; 30: 1834-1837. doi: 10.1007/s00134-004-2233-5.
8. Prekker ME, Scott NL, Hart D, et al. Point-of-care ultrasound to estimate central venous pressure: a comparison of three techniques. Crit Care Med 2013; 41: 833-841. doi: 10.1097/CCM.0b013e31827466b7.
9. Donahue SP, Wood JP, Patel BM, et al. Correlation of sonographic measurements of the internal jugular vein with central venous pressure. Am J Emerg Med 2009; 27: 851-855. doi: 10.1016/j.ajem.2008. 06.005.
10. Keller AS, Melamed R, Malinchoc M, et al. Diagnostic accuracy of a simple ultrasound measurement to estimate central venous pressure in spontaneously breathing critically ill patients. J Hospital Med 2009; 4: 350-355. doi: 10.1002/jhm.503.
11. Ciozda W, Kedan I, Kehl DW, et al. The efficacy of sonographic measurement of inferior vena cava diameter as an estimate of central venous pressure. Cardiovasc Ultrasound 2016; 14: 33. doi: 10.1186/s12947-016-0076-1.
12. Yang C, Yang Z, Chen X, et al. Inverted U-shaped relationship between central venous pressure and intra-abdominal pressure in the early phase of severe acute pancreatitis: a retrospective study. PLoS One 2015; 10: e0128493.
13. Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr 2015; 28: 1-39.e14. doi: 10.1016/j.echo.2014.10.003.
14. Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA 1993; 270: 2957-2963. doi: 10.1001/jama.270.24.2957.
15. Yildizdas D, Aslan N. Ultrasonographic inferior vena cava collapsibility and distensibility indices for detecting the volume status of critically ill pediatric patients. J Ultrason 2020; 20: e205-e209. doi: 10.15557/JoU.2020.0034.
16. Aslan N, Yildizdas D, Horoz OO, Coban Y, Arslan D, Sertdemir Y. Central venous pressure, global end-diastolic index, and the inferior vena cava collapsibility/distensibility indices to estimate intravascular volume status in critically ill children: A pilot study. Aust Crit Care 2021; 34: 241-245. doi: 10.1016/j.aucc.2020.08.005.
17. Parenti N, Scalese M, Palazzi C, et al. Role of internal jugular vein ultrasound measurements in the assessment of central venous pressure in spontaneously breathing patients: a systematic review. J Acute Med 2019; 9: 39-48. doi: 10.6705/j.jacme.201906_9(2).0001.
18. Siva B, Hunt A, Boudville N. The sensitivity and specificity of ultrasound estimation of central venous pressure using the internal jugular vein. J Crit Care 2012; 27: 315.e7-11. doi: 10.1016/j.jcrc.2011.09.008.
19. Xing CY, Liu YL, Zhao ML, et al. New method for noninvasive quantification of central venous pressure by ultrasound. Circ Cardiovasc Imaging 2015; 8: e003085. doi: 10.1161/CIRCIMAGING.114.003085.
20. Lipton B. Estimation of central venous pressure by ultrasound of the internal jugular vein. Am J Emerg Med 2000; 18: 432-434. doi: doi.org/10.1053/ajem.2000.7335.
21. Simon MA, Kliner DE, Girod JP, et al. Detection of elevated right atrial pressure using a simple bedside ultrasound measure. Am Heart J 2010; 159: 421-427. doi: 10.1016/j.ahj.2010.01.004.
22. Simon MA, Schnatz RG, Romeo JD, et al. Bedside ultrasound assessment of jugular venous compliance as a potential point-of-care method to predict acute decompensated heart failure 30-day readmission. J Am Heart Assoc 2018; 7: e008184. doi: doi.org/10.1161/JAHA.117.008184.
23. Uthoff H, Siegemund M, Aschwanden M, et al. Prospective comparison of noninvasive, bedside ultrasound methods for assessing central venous pressure. Ultraschall Med 2012; 33: E256-E262. doi: 10.1055/s-0031-1299506.
24. Avcil M, Kapci M, Dagli B, et al. Comparison of ultrasound-based methods of jugular vein and inferior vena cava for estimating central venous pressure. Int J Clin Exp Med 2015; 8: 10586-10594.
This is an Open Access journal, all articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0). License (http://creativecommons.org/licenses/by-nc-sa/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material, provided the original work is properly cited and states its license.
Quick links
© 2022 Termedia Sp. z o.o. All rights reserved.
Developed by Bentus.