Inferior Vena Cava Measurements Research Articles

Assessment of volume status of pediatric hemodialysis patients.

Accurate volume status assessment and dry weight achievement are the most challenging goals for a nephrologist. We aimed to evaluate the role of ultrasonographic parameters including lung ultrasound and inferior vena cava (IVC) measurements as practical methods of volume status assessment in children on hemodialysis by comparing them with established techniques, such as clinical evaluation and bioimpedance spectroscopy. A prospective cross-sectional study compared pre- and post-dialysis volume status using bioimpedance spectroscopy (BIS) parameters and clinical data with ultrasonographic lung B-lines and IVC parameters in children on regular hemodialysis. A total 60 children (mean age 9.4 ± 2.8years) were enrolled. Twenty patients (33.3%) were clinically overloaded to varying degrees (17 patients had mild to moderate signs of fluid overload and 3 patients had moderate to severe signs of fluid overload). All other patients (66.7%) were clinically euvolemic. Sonographic parameters were significantly lower post-dialysis than pre-dialysis, including lung B-line count and IVC diameter. IVC collapsibility index mean was significantly higher post-dialysis than pre-dialysis. There was a significant correlation between the lung B-line count, IVC parameters, and BIS-measured overhydration both before and after hemodialysis. Nine patients had ≥ 8 B-lines post-dialysis, only three of them were hypertensive. Clinical criteria alone are not specific for determining accurate fluid status in pediatric hemodialysis patients. Lung B-line score, IVC parameters, and BIS may be complementary to each other and to clinical data. Lung B-lines outperform IVC measurements and BIS in subclinical volume overload detection in pediatric hemodialysis patients.

#2058 IVC diameter and collapsibility via point-of-care ultrasound among clinically euvolemic Filipinos in Victoriano Luna Medical Center, Philippines

Abstract Background and Aims History, physical findings, and laboratory tests have limited sensitivity and specificity to assess relative intravascular volume or volume responsiveness. Inferior vena cava (IVC) ultrasound provides a direct assessment of relative intravascular volume status. The Journal of the American Society of Echocardiography (2010), recommended that an IVC diameter of <2.1 cm and collapsibility of >50% with a sniff indicates normal right atrial pressure of 3 mmHg (0-5 mmHg), while an IVC diameter of >2.1 cm with <50% inspiratory collapse indicates high right atrial pressure of 15 mmHg (10-20 mmHg). However, there have been occasions in the hospital setting wherein clinically hypervolemic Filipino patients were observed to have inferior vena cava diameters of less than 2.0 cm. This study aims to determine the average IVC diameter among clinically euvolemic Filipinos and to evaluate the applicability of standardized ultrasonographic IVC measurements in the Filipino population. Method This is a prospective observational study that included 45 clinically euvolemic patients and staff of Victoriano Luna Medical Center from 01 September 2023 to 01 November 2023. The demographic profile and anthropometric measurements of the volunteers were obtained. Ultrasound assessment was performed bedside and the IVC diameter was measured during passive respiration without sniff test 1 to 2 cm distal to the hepatic vein or 3 to 4 cm distal to the junction of the right atrium and inferior vena cava. The maximum and minimum diameters of the inferior vena cava was also measured using M-mode, and its collapsibility index was computed using the following formula: collapsibility index (CI) = (IVC max – IVC min) / IVC max. Categorical variables such as sex and comorbidities will be presented as frequencies and percentages while continuous variables such as age, body mass index, and inferior vena cava diameter and collapsibility will be presented as mean and standard deviation or median and interquartile range. Results The study group mainly consisted of males aged 65 years and below with normal body mass index for Asians. Cut-off values for the maximum inferior vena cava diameter were based on the venous excess ultrasound grading system, or VEXUS score, by Beaubien-Souligny et al. (2020) wherein congestion was considered at IVC diameters more than or equal to 2.0 cm. Of the 45 participants, 33 had maximum inferior vena cava diameter of less than 2.0 cm. Twenty-eight (28) out of 45 participants had a collapsibility index of more than 50%, which is indicative of normal right atrial pressure. Of the 33 with a maximum inferior vena cava diameter of less than 2.0 cm, 11 of which had a collapsibility index between 20 and 50%, and 22 with more than 50%. The remaining 12 participants had a maximum IVC diameter of more than or equal to 2.0 cm, with five having a collapsibility index between 20 and 50% and six with more than 50%. The mean maximum IVC diameter in the 45 volunteers on quiet respiration was 1.79 cm (+0.47), with an average computed collapsibility index of 54.43% (+19.78). Conclusion Thirty-three participants (73.33%) had a maximum inferior vena cava diameter of less than 2.0 cm, 22 of which have a collapsibility index of more than 50%. Among the 45 volunteers, the mean IVC maximum diameter on quiet respiration was 1.79 cm (+0.47), with an average computed collapsibility index of 54.43% (+19.78). Based on the results, standardized ultrasonographic IVC measurements can be applied on the Filipino population. Considering the Filipinos’ petite stature, the average IVC diameter among Filipinos is smaller and further investigation is warranted to establish clear cut-off values to identify plethoric IVCs in the Filipino setting.

Role of inferior vena cava assessment in volume management in acute kidney injury patients

BackgroundIntravascular volume assessment is critical to guiding volume management in patients with acute kidney injury (AKI). This study aimed to compare the impact of using inferior vena cava (IVC) diameter and collapsibility index (IVC-CI) measurements versus clinical assessment on the management of volume status and improvement of renal function in patients with AKI.MethodsThis prospective comparative study included 88 patients with AKI or AKI on top of chronic kidney disease (CKD) who were randomly allocated into two groups: In group 1, volume status was managed according to IVC assessment, while in group 2, volume status was managed according to clinical assessment. In addition, group 1 patients were assessed clinically and compared with IVC measurements in the same group.ResultsThere was moderate agreement between the IVC and clinical methods in diagnosing 86.4% of patients (P < 0.001) within group 1. The percentage of patients with edema increased post-treatment in group 2. There was no statistically significant difference between the two groups regarding renal recovery and survival.ConclusionBedside ultrasonographic IVC assessment is a non-invasive method that can facilitate volume management in AKI patients, helping to administer fluids more wisely without unintended excess fluid administration.

Point of Care Ultrasound for Diagnosis and Management in Heart Failure: A Targeted Literature Review.

Cardiac point of care ultrasound (POCUS) has shown increasing utility as a tool for diagnosing and managing heart failure (HF). Within cardiology, intravascular volume assessment leveraging visualization of the inferior vena cava (IVC) is a central aspect of care, as IVC size correlates with central venous pressure. This targeted literature review aimed to examine the existing literature assessing the use of POCUS in diagnosis and management of HF patients utilizing POCUS-based IVC measurement either alone or in combination with secondary methods. A targeted PubMed and Ovid database search up until August 28, 2023 using a keyword search was completed. Studies that did not include IVC assessment with POCUS in HF were excluded. The initial search using both PubMed and Ovid resulted in 370 journal publications. After exclusion criteria were used 15 studies were included in the review.Studies were grouped into three categories: 1) how well POCUS was able to identify HF, 2) whether POCUS-based findings correlated with other measures evaluating HF and was able to predict the effect of diuretic administration, and 3) whether POCUS-based findings served as a good prognostic indicator. The 5 studies that evaluated HF identification with POCUS found that both diagnostic sensitivity and specificity may reach 90%-100% when IVC measurement was coupled with a lung ultrasound assessing the presence of B-lines or pleural effusion. Five studies assessing POCUS findings correlating with other HF measures and diuretic effect found that IVC diameter changed significantly with diuretic administration (p<0.05). All 6 studies assessing POCUS as a predictor of long-term mortality or hospital readmission found measures that achieved statistical significance with p<0.05. Including POCUS as standard-of-care - both as a diagnostic tool in the emergency department and a management tool in in-patient and out-patient facilities - may improve the treatment of HF.

Accuracy of Pocket-sized Ultrasound Devices to Evaluate Inferior Vena Cava Diameter and Variability in Critically Ill Patients.

By using inferior vena cava (IVC) measurements, clinicians can detect fluid status and responsiveness and find out the etiology of hypotension, acute heart failure, and sepsis easier. Pocket-sized ultrasound devices (PSUD) may take this advantage a few steps further by their lower costs, user-friendly interface, and easily applicable structure.In this study, we aimed to determine the diagnostic value of a PSUD compared with a standard ultrasound device (SD) for the measurement of IVC diameter (IVCD) and its respiratory variability. We measured the inspiratory, expiratory diameters of IVC, and calculated the inferior vena cava collapsibility index (IVCCI). We investigated 42 intensive care unit (ICU) patients. There was no difference in inspiratory (PSUD: 1.34 ± 0.67 cm; SD: 1.35 ± 0.68 cm) and expiratory (PSUD: 1.98 ± 0.53 cm; SD: 2.01 ± 0.49 cm) IVCD among measurements with PSUD and SD (p > 0.05). There was also no difference between IVCCI's measured with PSUD (39 ± 20%) and SD (39 ± 20%) (p > 0.05). The Bland-Altman analysis revealed that the width of 95% limits of agreement were similar for both devices. There was a good inter-device agreement among PSUD and SD for measurements of IVCD, and there was no difference between IVCCI's measured using both ultrasound devices. We support that the idea of a PSUD is as reliable as a SD for IVC measurements. Inci K, Gürsel G. Accuracy of Pocket-sized Ultrasound Devices to Evaluate Inferior Vena Cava Diameter and Variability in Critically Ill Patients. Indian J Crit Care Med 2024;28(4):369-374.

Adrenal Vein Sampling: Does the Location of the Non-adrenal Venous Sample Matter?

PurposeAdrenal vein sampling (AVS) is used to lateralise and differentiate unilateral from bilateral aldosterone production in primary aldosteronism. The adrenal venous samples are standardised to a peripheral or low inferior vena cava (IVC) sample and compared. It is unknown whether the location of the non-adrenal sample affects the results. This study compares AVS results standardised to the low IVC and right external iliac vein (REIV).MethodsPatients who underwent AVS between March 2021 and May 2023 were included. All procedures were undertaken by a single operator (AA). Demographic data and AVS results were collected from patients’ electronic records. Catheterisation success and lateralisation were assessed using both low IVC and REIV samples. Equivalence test was used to compare the cortisol and aldosterone levels.ResultsEighty-one patients, (M: F = 38:43), aged between 29 and 74 were included. Bilateral successful adrenal vein cannulation was achieved in 79/81 (97.5%) cases. The mean cortisol levels from the REIV were statistically equivalent although there was a small and not biologically significant difference from the low IVC (respective geometric means 183 nmol/l vs. 185 nmol/l, p = 0.015). This small difference in cortisol may be due to accessory adrenal venous drainage into the IVC. The aldosterone and aldosterone/cortisol ratios were statistically equivalent. There was no discordance in selectivity or lateralisation when the IVC or REIV measurements were used.ConclusionThe IVC and REIV samples may be used interchangeably during AVS.Graphical

Abstract 13612: Association Between B-Type Natriuretic Peptide and Inferior Vena Cava Diameter as a Measure of Hypovolemia in Cancer Patients

Introduction: Hypovolemia is frequently seen in cancer patients due to catabolism, cachexia, and decreased oral intake. However, volume status assessment in this population is often difficult due to competing comorbid conditions such as edema. Elevated B-type natriuretic peptide (BNP) is an established biomarker of myocardial wall stress in patients with hypervolemia. We sought to determine if very low BNP could be an objective marker of hypovolemia in cancer patients Hypothesis: In cancer patients undergoing treatment, is low BNP level (&lt;10 pg/mL) associated with small inferior vena cava (IVC) diameter (&lt; 1.4 cm) - an established marker of hypovolemia on transthoracic echocardiography (TTE)?We hypothesize that BNP &lt;10 pg/mL is associated with small IVC as a marker of hypovolemia in cancer patients. Methods: We conducted a retrospective study (N=91) with solid malignancies, undergoing chemo- and/or radiation therapy (RT), divided into 3 groups based on BNP values in pg/mL: low (BNP &lt;10), normal (BNP 10-100) and high (BNP&gt;100). Retrospective data were obtained between 2016-2023 from Rush University Medical Center Cardio-Oncology Registry. IVC measurements by 2 medial trainees (Cohen’s intraclass correlation coefficient = 0.87, p &lt; 0.01) were acquired from formal TTEs obtained within 1 week of BNP measurements. Linear regression was used to calculate the adjusted means (for age, sex, BMI, blood pressure, creatinine, RT, TSH) of the 2 measured IVC diameters per datapoint. Mean difference in IVC diameters was compared between the 3 BNP groups. Results: The population mean age was 59.99 ± 12.19, 67% women. Adjusted mean IVC measurements were 1.89cm, 1.55cm, and 1.26cm for the high, normal, and low BNP groups respectively. The mean difference in IVC diameters between high and low BNP groups was 0.628 ±0.164 cm (p&lt;0.01). Conclusions: In cancer patients undergoing treatment, very low BNP (&lt;10pg/mL) was associated with small IVC as a marker of hypovolemia. In this group of patients, BNP measured with routine lab data is a readily available tool to identify individuals with hypovolemia where other measures of volume status such as physical exams might be uncertain.

The ultrasound assessment of the inferior vena cava collapsibility in the prone volunteers through a new acoustic window: a prospective observational study

INTRODUCTION: Ultrasound assessment of inferior vena cava (IVC) collapsibility is used in clinical practice to assess patients' volume status. Finding the subject in the prone position limits the ability to assess IVC collapse by the traditional method, which requires the use of alternative methods. OBJECTIVE: Conducting a comparative assessment of the IVC collapse index in healthy volunteers in the back position and in the pro position using a new acoustic window. MATERIALS AND METHODS: Ultrasound observation was performed in 25 adult healthy volunteers of both sexes. Ultrasound measurement of IVC was carried out sequentially in the position of volunteers on the back and abdomen. The mean (M) and standard deviation (SD) of the maximum and minimum IVC size. The values of the collapsing index (CI) obtained during the study are presented as a median (Me) and quartiles (Q1–Q3). Wilcoxon's nonparametric test was selected for comparative analysis (significance level accepted 0.05). RESULTS: Measurements of the diameter of the inferior vena cava obtained the following results: the average maximum and minimum vein size in volunteers in the supine position were 1.58 ± 0.37 cm and 1.30 ± 0.36 cm, respectively; in prone — 1.51 ± 0.37 cm and 1.24 ± 0.36 cm, respectively. Me (Q1–Q3) IVC-CI values (%) in volunteers in the supine and in the prone position of the voice were 16.84 (8.86–24.39) and 15.63 (10.23–24.77), respectively. Statistical analysis of the obtained results did not reveal a significant difference between CI values (p = 0.861). CONCLUSIONS: The absence of a statistically significant difference in IVC-CI values in the supine and abdominal volunteers demonstrates the possibility of using a new acoustic window to assess volume status in the clinical setting in patients in the prone position.

Association of infraclavicular axillary vein diameter and collapsibility index with general anesthesia-induced hypotension in elderly patients undergoing gastrointestinal surgery: an observational study

BackgroundThe collapse index of inferior Vena Cava (IVC) and its diameter are important predictive tools for fluid responsiveness in patients, especially critically ones. The collapsibility of infraclavicular axillary vein (AXV) can be used as an alternative to the collapsibility of IVC (IVC-CI) to assess the patient’s blood volume.MethodsA total of 188 elderly patients aged between 65 and 85 years were recruited for gastrointestinal surgery under general anesthesia. Ultrasound measurements AXV and IVC were performed before induction of general anesthesia. Patients were grouped in accordance to the hypotension after induction. ROC curves were used to analyze the predictive value of ultrasound measurements of AXV and IVC for hypotension after induction of anesthesia. Pearson linear correlation was used to assess the correlation of ultrasound measurements and decrease in mean arterial blood pressure (MAP).ResultsThe maximum diameter of AXV(dAXVmax) and the maximum diameter of IVC (dIVCmax) were not related to the percentage decrease in MAP; the collapsibility of AXV (AXV-CI) and IVC-CI were positively correlated with MAP changes (correlation coefficients:0.475, 0.577, respectively, p < 0.001). The areas under the curve (AUC) was 0.824 (0.759–0.889) for AXV-CI, and 0.874 (0.820–0.928) for IVC-CI. The optimal threshold for AXV-CI was 31.25% (sensitivity 71.7%, specificity 90.1%), while for IVC-CI was 36.60% (sensitivity 85.9%, specificity 79.0%). Hypotension and down-regulation of MAP during induction can be accurately predicted by AXV-Cl after correction for confounding variables.ConclusionInfraclavicular axillary vein diameter has no significant correlation with postanesthesia hypotension, whereas AXV-CI may predict postanesthesia hypotension during gastrointestinal surgery of the elderly.Trial registrationThis study was registered in the Clinical Trial Registry of China on 05/06/2022 (ChiCTR2200060596).

Evaluation of an artificial intelligence-based system for echocardiographic estimation of right atrial pressure

Current noninvasive estimation of right atrial pressure (RAP) by inferior vena cava (IVC) measurement during echocardiography may have significant inter-rater variability due to different levels of observers’ experience. Therefore, there is a need to develop new approaches to decrease the variability of IVC analysis and RAP estimation. This study aims to develop a fully automated artificial intelligence (AI)-based system for automated IVC analysis and RAP estimation. We presented a multi-stage AI system to identify the IVC view, select good quality images, delineate the IVC region and quantify its thickness, enabling temporal tracking of its diameter and collapsibility changes. The automated system was trained and tested on expert manual IVC and RAP reference measurements obtained from 255 patients during routine clinical workflow. The performance was evaluated using Pearson correlation and Bland-Altman analysis for IVC values, as well as macro accuracy and chi-square test for RAP values. Our results show an excellent agreement (r=0.96) between automatically computed versus manually measured IVC values, and Bland-Altman analysis showed a small bias of -\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document}0.33 mm. Further, there is an excellent agreement ((p<0.01\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(p<0.01$$\\end{document}) between automatically estimated versus manually derived RAP values with a macro accuracy of 0.85. The proposed AI-based system accurately quantified IVC diameter, collapsibility index, both are used for RAP estimation. This automated system could serve as a paradigm to perform IVC analysis in routine echocardiography and support various cardiac diagnostic applications.

Noninvasive Hemodynamic Profiling of Patients Undergoing Hemodialysis Using a Handheld Ultrasound Device

INTRODUCTION: Accurate determination of volume status for patients with end-stage renal disease is essential in determining ultrafiltration rate during hemodialysis (HD). To complement the current dry weight method, inferior vena cava (IVC) collapsibility, made accessible by point of-care ultrasonography, is considered. This study determined the utility of IVC measurement in estimating the volume status of patients during HD in comparison to clinical parameters. METHODS: A single-center cross-sectional design including 53 HD patients was conducted, with IVC measurements done through the Butterfly iQ ultrasound (Butterfly Network, Burlington, Massachusetts). RESULTS: Most patients were hypervolemic before HD based on weight (94.3%) and IVC collapsibility index (IVC-CI; 75.5%), but only 30% had clinical symptoms. Body weight, maximum IVC diameter, minimum IVC diameter, and indexed IVC size significantly decreased after HD, whereas IVC-CI, blood pressure, and heart rate were unchanged. For the subset of patients with symptoms, absolute values of IVC measures were higher, but did not significantly change after HD, unlike in those without symptoms. For volume classification, there are discrepancies in the classifications based on the different measures, with most improvement seen when weight was used, but which was not reflected in IVC-CI. Change in weight and IVC measures were not significantly correlated. DISCUSSION: This pilot study showed that the current dry weight method provides ultrafiltration rate estimation without causing intradialytic events. However, IVC can be a supplemental parameter to set higher targets and increase volume removal enough to cause intravascular change, especially in symptomatic patients. The incongruencies in classifying volume status suggest that there is no single measure to determine hemodynamic status and that using multiple parameters may provide a more reliable estimate. KEYWORDS: inferior vena cava measurement, volume status in hemodialysis, point-of-care ultrasonography

Assessment of the inferior vena cava collapsibility from subcostal and trans-hepatic imaging using both M-mode or artificial intelligence: a prospective study on healthy volunteers

PurposeAssessment of the inferior vena cava (IVC) respiratory variation may be clinically useful for the estimation of fluid-responsiveness and venous congestion; however, imaging from subcostal (SC, sagittal) region is not always feasible. It is unclear if coronal trans-hepatic (TH) IVC imaging provides interchangeable results. The use of artificial intelligence (AI) with automated border tracking may be helpful as part of point-of-care ultrasound but it needs validation.MethodsProspective observational study conducted in spontaneously breathing healthy volunteers with assessment of IVC collapsibility (IVCc) in SC and TH imaging, with measures taken in M-mode or with AI software. We calculated mean bias and limits of agreement (LoA), and the intra-class correlation (ICC) coefficient with their 95% confidence intervals.ResultsSixty volunteers were included; IVC was not visualized in five of them (n = 2, both SC and TH windows, 3.3%; n = 3 in TH approach, 5%). Compared with M-mode, AI showed good accuracy both for SC (IVCc: bias − 0.7%, LoA [− 24.9; 23.6]) and TH approach (IVCc: bias 3.7%, LoA [− 14.9; 22.3]). The ICC coefficients showed moderate reliability: 0.57 [0.36; 0.73] in SC, and 0.72 [0.55; 0.83] in TH. Comparing anatomical sites (SC vs TH), results produced by M-mode were not interchangeable (IVCc: bias 13.9%, LoA [− 18.1; 45.8]). When this evaluation was performed with AI, such difference became smaller: IVCc bias 7.7%, LoA [− 19.2; 34.6]. The correlation between SC and TH assessments was poor for M-mode (ICC = 0.08 [− 0.18; 0.34]) while moderate for AI (ICC = 0.69 [0.52; 0.81]).ConclusionsThe use of AI shows good accuracy when compared with the traditional M-mode IVC assessment, both for SC and TH imaging. Although AI reduces differences between sagittal and coronal IVC measurements, results from these sites are not interchangeable.

ROLE OF ULTRASONOGRAPHIC INFERIOR VENACAVAL ASSESSMENT IN SURGERIES CONDUCTED UNDER GENERAL ANAESTHESIA-A PROSPECTIVE OBSERVATIONAL STUDY

Background: One of the most frequent side effects following the induction of general anaesthesia during surgery is hypotension. The goal of our study was to determine if there was a connection between the maximum inferior vena cava (IVC) diameter prior to induction, the collapsibility index (CI), and the post-induction decrease in mean arterial blood pressure in patients undergoing operations under general anaesthesia. Materials and Methods: Eighty patients who underwent procedures under general anaesthesia at Gandhi Medical College Bhopal and associated tertiary care hospital were included in a prospective observational research. Prior to starting general anaesthesia, the IVC was evaluated. For each surgical patient, the maximum and minimum IVC diameters (IVCD max and IVCD min) as well as the CI were assessed. Results: According to the criteria of hypotension as defined, 31(38.75%) of the patients developed post-induction hypotension. Four patients had MAP &lt;60 mmHg after induction of anesthesia. Post-induction hypotension was seen in patients with increased age. Patients with smaller IVCD max (P = 0.02), smaller IVCD min (P = 0.003), and higher CI% (P = 0.004) developed hypotension after induction of anesthesia. Percentage drop in MAP was 33.7 ± 4.48% (P = 0.002) in patients who developed post-induction hypotension. Conclusion: Predicting post-induction hypotension caused by hypovolemia in surgical patients with IVC measurement using ultrasound is a reliable strategy.

Sonographic measurements of Inferior Vena Cava, Aorta, anda IVC/aorta ratio in healthy children.

Assessment of intravascular volume status is important in pediatric patients admitted to the emergency departments and pediatric intensive care units. Inferior vena cava (IVC) diameter and collapsibility index are used to evaluate the intravascular volume status in adults. The normal range of IVC diameter is available for adults and the normal range considered for adults is between 1.7 to 2.1 cm, but such normative data is limited for children of all ages. Our aim in this study was to obtain the IVC and the aorta diameter reference values and the mean vena cava collapsibility index in healthy and normovolemic children. Vena cava inferior and aorta images in B mode were obtained. IVC diameter in the inspiratory and the largest IVC diameter in the expiratory were recorded, and the vena cava collapsibility index was calculated. Ultrasonographic measurements were performed in total on 1938 children. A significant positive correlation was found between IVC and aorta diameters with age. The collapsibility index was found as 37.2% (SD 11.8) in the overall study population. In addition, the reference values for the IVC and aorta diameters obtained from the measurements were also acquired. We believe that our IVC and aorta diameter measurements obtained from a large number of participants may be used as reference values in emergency departments and intensive care units.

IVC measurement for the noninvasive evaluation of central venous pressure.

Central venous pressure (CVP) is one of only a handful of variables that can be used to assess a patient's volume status to attempt to optimize stroke volume. The gold standard method for assessing CVP is though pulmonary artery catheterization, which is invasive and risks severe complications such as pneumothorax and cardiac conduction abnormalities. Current noninvasive methods for estimating CVP such as jugular venous pressure assessment are imperfect with wide inter-examiner variability. The inferior vena cava (IVC) is a highly compliant vessel that uniquely does not constrict in response to hypovolemia, making it an ideal, noninvasive surrogate for the estimation of CVP. A range of IVC indices including minimum and maximum IVC diameter and fraction of IVC collapse with inspiration (known as collapsibility index) have been studied with highly variable results that range from excellent to poor correlation between these values and CVP. Despite this inconsistency in findings, multiple schemes have been proposed to attempt to estimate CVP from IVC measurements, but when prospectively tested, none has been shown to be accurate. Since the most recent 2015 American Society of Echocardiography guidelines, multiple studies have identified unique ways of improving the accuracy of IVC measurement, which could translate into better CVP estimation. The goal of this review is to summarize the many, often conflicting studies that exist in this area, and provide recommendations for future studies based on our findings.

Inferior vena cava ultrasonography before general anesthesia cannot predict arterial hypotension in patients undergoing vascular surgery.

Intraoperative hypotension (IH) is an independent predictor of mortality. Some experts have suggested that ultrasound measurement of the inferior vena cava (IVC) in spontaneous ventilation can predict IH. To evaluate the capacity of ultrasound measures of IVC in spontaneous ventilation to predict episodes of IH after anaesthesia induction. We studied 55 high-risk cardiac patients undergoing vascular surgery. The maximum (dIVCmax) and minimum (dIVCmin) diameter of the IVC were measured and the collapsibility index CI = (dIVCmax-dIVCmin)/dIVCmax was calculated prior to anaesthesia induction. Three definitions of IH were used: systolic blood pressure (SBP) less than 100 mmHg, mean arterial pressure (MAP) less than 60 mmHg, and a decrease in MAP greater than or equal to 30% compared to baseline. There were no significant differences in dIVCmax or in CI between patients presenting IH after anaesthesia induction and those who did not. ROC curves for dIVCmax showed an area under the curve of 0.55 (0.39-0.70), 0.69 (0.48-0.90), and 0.57 (0.42-0.73) and ROC curves for the CI were 0.62 (0.47-0.78), 0.60 (0.41-0.78) and 0.62 (0.47-0.78) for the 3 definitions of IH (<100 mmHg, MAP < 60 mmHg, and MAP ≥30% baseline), respectively. Ultrasound measurements of IVC in spontaneous ventilation are not good predictors of IH after anaesthesia induction in these patients. The optimal cut-off points show low specificity and moderate sensitivity for predicting IH.

Is Inferior Vena Cava Diameter, a Reliable Indicator for Fluid Status in End-Stage Renal Disease Patients? - A Prospective Observational Study

Introduction: Adequate allograft perfusion is the key component of renal-transplant surgeries. This requires meticulous management of volume status in end-stage renal disease (ESRD) patients on maintenance hemodialysis (MHD). Various methods have been tried to unveil the most dependable parameter. So far, central venous pressure (CVP) has been a reliable parameter for guiding fluid therapy. Recently, in the past decade, inferior vena cava (IVC) diameter (IVCD) has emerged as a promising indicator for volume assessment in critically ill patients. However, very limited data are available regarding use of IVC diameter in ESRD patients. This study is an attempt to determine the efficacy of IVC diameter in predicting the volume status of renal-transplant recipients by comparing it with conventional method, CVP. Methods: Enrolling 60 live donor renal-transplant recipients from a single center, the mean IVCD and IVC collapsibility index (IVC-CI) were measured and compared with CVP. IVC measurements were recorded using bedside ultrasonography. CVP was measured using central venous catheter placed in superior vena cava, through a water column on a standardized scale. The data were analyzed using SPSS Version 20. Results: The mean age of the participants was 38.92 ± 10.46 years. The mean CVP was 6.78 ± 2.86 cmH2O, the mean IVCD was 1.30 ± 0.43 cm, the mean IVC-CI was 24.27% ± 15.45%. Based on Pearson's correlation test, there was no linear correlation between CVP and IVCD as well as CVP and IVC-CI. Conclusion: For the assessment of fluid status and fluid responsiveness in ESRD patients with MHD, ultrasound assessment of IVCD and IVC-CI is not routinely helpful.

Inferior Vena Cava Diameter Measurement Provides Distinct and Complementary Information to Right Atrial Pressure in Acute Decompensated Heart Failure

Inferior vena cava (IVC) measurements correlate only modestly with right atrial pressure (RAP). Part of this inaccuracy is due to the high compliance of the venous system, where a large change in blood volume may result in only a small change in pressure. As such, the information provided by the IVC may be different rather than redundant. We analyzed patients in the ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) trial who had both pulmonary artery catheter and IVC measurements at baseline (n = 108). There was only a modest correlation between baseline RAP and IVC diameter (r = 0.41; P < 0.001). Hemoconcentration, defined as an increase in hemoglobin levels between admission and discharge, was correlated with decrease in IVC diameter (r = 0.35; P = 0.02) but not with a decrease in RAP (r = 0.01; P = 0.95). When patients had both IVC and RAP measurements that were below the median, survival rates were superior to the rates of those who had only 1 measurement below the median, and when both rates were above the median, patients fared the worst (P = 0.002). IVC and RAP have limited correlation with each another, and changes in intravascular volume appear to correlate better with IVC diameter rather than with RAP. Furthermore, complementary information is provided by pressure and volume assessments in acute decompensated heart failure.

Inferior Vena Cava Edge Tracking Echocardiography: A Promising Tool with Applications in Multiple Clinical Settings.

Ultrasound (US)-based measurements of the inferior vena cava (IVC) diameter are widely used to estimate right atrial pressure (RAP) in a variety of clinical settings. However, the correlation with invasively measured RAP along with the reproducibility of US-based IVC measurements is modest at best. In the present manuscript, we discuss the limitations of the current technique to estimate RAP through IVC US assessment and present a new promising tool developed by our research group, the automated IVC edge-to-edge tracking system, which has the potential to improve RAP assessment by transforming the current categorical classification (low, normal, high RAP) in a continuous and precise RAP estimation technique. Finally, we critically evaluate all the clinical settings in which this new tool could improve current practice.

Preoperative Ultrasonographic Evaluation of Subclavian Vein and Inferior Vena Cava for Predicting Hypotension Associated with Induction of General Anesthesia.

Introduction:Induction of general anesthesia is often associated with hypotension and is a common scenario faced by anesthesiologists. Intraoperative hypotension can have detrimental effects and cause various adverse effects leading to an extended hospital stay. Patients' preinduction volume status can have an effect on postinduction blood pressure. Ultrasonography is a useful tool for measuring intravascular volume status. We studied the ability of ultrasonographic measurement of subclavian vein (SCV) and inferior vena cava (IVC) diameter, collapsibility index (CI) to predict hypotension after induction of general anesthesia.Materials and Methods:We included 120 patients in our study. SCV measurements during spontaneous and deep inspiration and IVC measurements were taken before induction and postinduction blood pressure was monitored. Patients with mean arterial blood pressure <60 mmHg or with a 30% decrease from baseline were considered to be having hypotension.Results:The CI of IVC with a cutoff 37% showed sensitivity of 94% and specificity of 84% which was statistically significant. The CI of 36% of SCV during deep breathing was found to have high sensitivity and specificity of 90% and 87%.Conclusion:Our study in spontaneously breathing preoperative patients shows that SCV CI in deep breathing and IVC CI is very sensitive and reliable in predicting postinduction hypotension. Bedside ultrasound measurements can be easily done to obtain valuable information to recognize patients who could be at risk from postinduction hypotension.