Changes In Inferior Vena Cava Diameter Research Articles

Changes in the Inferior Vena Cava Are More Sensitive Than Venous Pressure During Fluid Removal: A Proof-of-Concept Study

Congestion is central to the pathophysiology of heart failure (HF); thus, tracking congestion is crucial for the management of patients with HF. In this study we aimed to compare changes in inferior vena cava diameter (IVCD) with venous pressure following manipulation of volume status during ultrafiltration in patients with cardiac dysfunction. Patients with stable hemodialysis and with systolic or diastolic dysfunction were studied. Central venous pressure (CVP) and peripheral venous pressure (PVP) were measured before and after hemodialysis. IVCD and PVP were measured simultaneously just before dialysis, 3 times during dialysis and immediately after dialysis. Changes in IVCD and PVP were compared at each timepoint with ultrafiltration volumes. We analyzed 30 hemodialysis sessions from 20 patients. PVP was validated as a surrogate for CVP. Mean ultrafiltration volume was 2102 ± 667 mL. IVCD discriminated better ultrafiltration volumes ≤ 500 mL or ≤ 750 mL than PVP (AUC 0.80 vs 0.62, and 0.80 vs 0.56, respectively; both P< 0.01). IVCD appeared to track better ultrafiltration volume (P< 0.01) and hemoconcentration (P< 0.05) than PVP. Changes in IVCD were of greater magnitude than those of PVP (average change from predialysis: -58 ± 30% vs -28 ± 21%; P< 0.001). In patients undergoing ultrafiltration, changes in IVCD tracked changes in volume status better than venous pressure.

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

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.

Sensitivity and Reproducibility of Inferior Vena Cava Diameter and Superior Vena Cava Flow Velocity Measurements to Changes in Cardiac Preload in Subjects with Hypertension.

Objectives:We investigated the sensitivity and reproducibility of inferior vena cava (IVC) diameters and superior vena cava (SVC) flow velocities in detecting changes in cardiac preload in clinically euvolemic subjects with hypertension.Methods:Measurements were obtained during passive leg raising (PLR) and lower limb venous occlusion (LVO), interventions which respectively transiently increase and decrease cardiac preload. Measurements were made in 36 subjects and repeated on two separate occasions to examine reproducibility.Results:During PLR, there was no significant change in IVC diameters, but peak flow velocity of the SVC S wave increased by 6.5 (95% confidence interval 1.6–11.3) cm/s (P = 0.01). During LVO, IVC diameter in expiration decreased by 3.2 (1.7–4.7) mm and the SVC S wave decreased by 9.7 (4.4–14.7) cm/s (P < 0.001). Venae cavae-derived indices can be used to assess changes in preload within the physiological range in euvolemia.Conclusions:Despite suboptimal reproducibility of baseline measurements, high agreeability between the changes in IVC diameter and SVC flow after LVO suggests that these indices can be used to monitor changes in cardiac preload.

SUN-081 USE OF HANDHELD ULTRASOUND TO ESTIMATE FLUID STATUS OF HEMODIALYSIS PATIENTS

Accurate assessment of fluid status in hemodialysis patients presents a significant challenge. Nephrologists have long relied on dry weight estimation based solely on clinical parameters to decide the ultrafiltration volume for patients with end-stage kidney disease on dialysis. However, this method is far from accurate and many patients recurrently suffer from signs and symptoms of fluid overload or circulatory collapse from overaggressive ultrafiltration. Invasive methods such as measurement of central venous pressure cannot be used routinely. We evaluated the usefulness of inferior vena cava (IVC) diameter measured by handheld ultrasound in the estimation of fluid status in patients before and after hemodialysis. Clinical assessment included patients’ symptoms, weight, blood pressure, heart rate, and presence of edema before and after dialysis session. Dry weight was assessed based on the above parameters. Each patient underwent measurement of inferior vena cava before and after hemodialysis. The anteroposterior IVC diameter (IVCD) was measured 1.5 cm below the diaphragm in the hepatic segment in supine position during normal inspiration and expiration. Thirty hemodialysis patients (mean age 51.6±18.03 years) were evaluated in outpatient dialysis unit. Following hemodialysis mean IVCe (IVC diameter in expiration) decreased from 1.40±0.38 to 0.91±0.30 cm (p<0.001). Similarly, mean IVCi (IVC diameter in inspiration) decreased from 0.67±0.34 to 0.35±0.19 cm (p<0.001). Changes in IVCD were significantly correlated with alterations in body weight following dialysis (p<0.0001). The IVC collapsibility index (IVC-CI, per cent of change in IVC diameter in expiration vs. inspiration) increased significantly from 0.53±0.18 to 0.68±0.18 after dialysis (p=0.002). IVC diameter and IVC-CI clearly reflected alterations in fluid status. Regarding the clinical parameters of fluid status, following hemodialysis, mean heart rate increased from 81.17±5.21 beats per minute to 86.50±7.99, (p=0.003), systolic blood pressure increased from 148.67±26.36 mmHg to 155.00±28.50, (p=0.05), and diastolic blood pressure increased from 78.62±12.74 mmHg to 84.83±14.55, (p<0.001). Our findings support the applicability of IVCD measurement and IVC-CI in the estimation of fluid status in end stage kidney disease patients on hemodialysis. The clinical parameters of fluid status including heart rate, systolic blood pressure, and diastolic blood pressure suggest that significant numbers of patients underwent excess ultrafiltration based on their traditional dry weight calculation. Thus, using IVC parameters before and during hemodialysis might give a better estimation of fluid status of the patient and guide the amount of ultrafiltration to be done.

Comparison of Superior Vena Cava and Inferior Vena Cava Diameter Changes by Echocardiography in Predicting Fluid Responsiveness in Mechanically Ventilated Patients.

Context:Resuscitation of critically ill patients requires an accurate assessment of the patient's intravascular volume status. Passive leg raise cause auto transfusion of fluid to the thoracic cavity.Aims:This study aims to assess and compare the efficacy of superior vena cava (SVC) and inferior vena cava (IVC) diameter changes in response to passive leg raise (PLR) in predicting fluid responsiveness in mechanically ventilated hemodynamically unstable critically ill patients.Methods:We enrolled 30 patients. Predictive indices were obtained by transesophageal and transthoracic echocardiography and were calculated as follows: (Dmax − Dmin)/Dmax for collapsibility index of SVC (cSVC) and (Dmax − Dmin)/Dmin for distensibility index of IVC (dIVC), where Dmax and Dmin are the maximal and minimal diameters of SVC and IVC. Measurements were performed at baseline and 1 min after PLR. Patients were divided into responders (increase in cardiac index (CI) ≥10%) and nonresponders (NR) (increase in CI <10% or no increase in CI).Results:Among those included, 24 (80%) patients were R and six were NR. There was significant rise in mean arterial pressure, decrease in heart rate, and decrease in mean cSVC from baseline to 1 min after PLR among responders. The best threshold values for discriminating R from NR was 35% for cSVC, with sensitivity and specificity of being 100%, and 25% for dIVC, with 54% sensitivity and 86.7% specificity. The areas under the receiver operating characteristic curves for cSVC and dIVC regarding the assessment of fluid responsiveness were 1.00 and 0.66, respectively.Conclusions:cSVC had better sensitivity and specificity than dIVC in predicting fluid responsiveness.

Comparison of cardiac output, IVC diameters and lactate levels in prediction of mortality in patients in emergency department; An observational study.

Objective:Fluid overload is an independent marker for mortality in critically ill patients. Assessment of fluid status and fluid responsiveness is crucial for the management of these patients. In this study, we compared the lactate level, inferior vena cava (IVC) diameter and non-invasive cardiac output (CO) monitoring in prediction of mortality in emergency department.Methods:This was a cross sectional observational study which comprised of 68 patients and was performed in ED of Tabriz University of Medical Sciences, Iran, from Sept 2016 until Sept 2017. IVC diameter was measured before the P-wave on ECG to avoid interference with a-wave and v-wave on the venous pressure curve, and during maximal inspiration and expiration to avoid Valsalva-like maneuvers. An arterial lactate sample was taken from all patients before performing the initial resuscitation. All patients underwent non-invasive CO monitoring by CO2 rebreathing technique. Mortality was noted on day 28.Results:Deceased patients had a significantly low level of IVC diameters, less CO values and more lactate levels. However, based on ROC curve analysis, the prediction accuracy and validity of both CO values obtained by rebreathing CO2 and IVC diameter was poor and the highest accuracy was obtained by lactate level assessment.Conclusion:Initial lactate value is a reliable parameter for prediction of mortality in non-traumatic critically ill patients. IVC diameter changes during spontaneous ventilation and non-invasive CO monitoring does not possess acceptable accuracy for prediction of mortality in these patients.

Robot Assisted Surgery of the Vena Cava: Perioperative Outcomes, Technique, and Lessons Learned at The Mayo Clinic.

Introduction: This study aims to describe robot assisted surgery of the inferior vena cava (IVC) by assessing techniques utilized, perioperative outcomes, complications, and long-term patency of the IVC. Methods: A retrospective review was performed on all robotic surgeries involving dissection and repair of the IVC at our institution. Patient characteristics, operative reports, and follow-up visits were analyzed. Preoperative and postoperative imaging was independently reviewed by a single radiologist to determine changes in IVC diameter. Complications were analyzed according to early (<30 days) vs late (>30 days). Results: Thirty-four patients underwent robot assisted surgery of the vena cava from 2008 to 2018. Twenty-six cases were performed for urologic malignancy, four were performed for IVC filter explantation, and four renal vein transpositions were performed for nutcracker syndrome. Twenty-four of the 26 patients with urologic malignancy underwent radical nephrectomy with IVC tumor thrombectomy. Three cases were converted to open. Median length of stay was two nights, and mean estimated blood loss (EBL) was 375 mL. There were five complications, ranging from Clavien-Dindo grade II-IIIa, four of which were early complications. No patients required return to the operating room, and there were no perioperative mortalities. IVC diameter was reduced by 41% on axial diameter, with no patients experiencing compromised venous return. Conclusion: Robot assisted surgery offers the advantage of minimally invasive surgery with the ability to apply open surgical principles. In our series, an experienced multidisciplinary team approach yielded low EBL, short length of stay, and low complication rates.

Use of Handheld Ultrasound to Estimate Fluid Status of Hemodialysis Patients

Introduction: Accurate assessment of fluid status in hemodialysis patients presents a significant challenge. Nephrologists have long relied on dry weight estimation based solely on clinical parameters to decide the ultrafiltration volume for patients with end-stage kidney disease on dialysis. However, this method is far from accurate and many patients recurrently suffer from signs and symptoms of fluid overload or circulatory collapse from overaggressive ultrafiltration. Invasive methods such as measurement of central venous pressure cannot be used routinely. We evaluated the usefulness of inferior vena cava (IVC) diameter measured by handheld ultrasound in the estimation of fluid status in patients before and after hemodialysis. Materials and Methods: Clinical assessment included patients’ symptoms, weight, blood pressure, heart rate, and presence of edema before and after dialysis session. Dry weight was assessed based on the above parameters. Each patient underwent measurement of inferior vena cava before and after hemodialysis. The anteroposterior IVC diameter (IVCD) was measured 1.5 cm below the diaphragm in the hepatic segment in supine position during normal inspiration and expiration.Results: Thirty hemodialysis patients (mean age 51.6±18.03 years) were evaluated in outpatient dialysis unit. Following hemodialysis mean IVCe (IVC diameter in expiration) decreased from 1.40±0.38 to 0.91±0.30 cm (p&lt;0.001). Similarly, mean IVCi (IVC diameter in inspiration) decreased from 0.67±0.34 to 0.35±0.19 cm (p&lt;0.001). Changes in IVCD were significantly correlated with alterations in body weight following dialysis (p&lt;0.0001). The IVC collapsibility index (IVC-CI, per cent of change in IVC diameter in expiration vs. inspiration) increased significantly from 0.53±0.18 to 0.68±0.18 after dialysis (p=0.002). IVC diameter and IVC-CI clearly reflected alterations in fluid status. Regarding the clinical parameters of fluid status, following hemodialysis, mean heart rate increased from 81.17±5.21 beats per minute to 86.50±7.99, (p=0.003), systolic blood pressure increased from 148.67±26.36 mmHg to 155.00±28.50, (p=0.05), and diastolic blood pressure increased from 78.62±12.74 mmHg to 84.83±14.55, (p&lt;0.001).Conclusions: Our findings support the applicability of IVCD measurement and IVC-CI in the estimation of fluid status in end stage kidney disease patients on hemodialysis. The clinical parameters of fluid status including heart rate, systolic blood pressure, and diastolic blood pressure suggest that significant numbers of patients underwent excess ultrafiltration based on their traditional dry weight calculation. Thus, using IVC parameters before and during hemodialysis might give a better estimation of fluid status of the patient and guide the amount of ultrafiltration to be done.

Preoperative and Postoperative Assessment of Ultrasonographic Measurement of Inferior Vena Cava: A Prospective, Observational Study.

Background: Ultrasound measurement of dynamic changes in inferior vena cava (IVC) diameter and collapsibility index (CI) are used to estimate the fluid responsiveness and intravascular volume status. We conducted an analysis to quantify the sonographic measurement of IVC diameter changes in adult patients at the preoperative and postoperative periods. Methods: Ultrasonography was performed on 72 patients scheduled for surgery with American Society of Anesthesiologists physical status I to III. Quantitative assessments of the end-expiration (Dmin), end-inspiration (Dmax), and CI at preoperative and postoperative period were compared in a prospective, observational study. The patients received intravenous fluid according to standard protocol regimes peroperatively. Results: Ultrasonography of IVC measurement was unsuccessful in 12.5% of patients and 63 patients remained for analyses. The mean age was 43.29 ± 17.22 (range 18–86) years. The average diameter of the Dmin, Dmax, and dIVC preoperative and postoperative were 1.99 ± 0.31 vs. 2.05 ± 0.29 cm, 1.72 ± 0.33 vs. 1.74 ± 0.32 cm, 14.0 ± 9.60% vs. 15.14 ± 11.18%, respectively (p > 0.05). CI was positively associated preoperatively and postoperatively (regression coefficient = 0.438, p < 0.01). Conclusion: The diameter of the IVC did not change preoperatively and postoperatively in adult patients with standard fluid regimens. The parameters of the IVC diameter increased postoperatively according to the preoperative period.

Evaluation of Subclinical Fluid Overload Using Lung Ultrasound and Estimated Plasma Volume in the Postoperative Period Following Kidney Transplantation

AimB-lines count measured with lung ultrasound (LUS) quantifies extravascular lung water and is validated in the setting of acute cardiac failure or chronic dialysis. Patients are often kept in moderately overhydrated states during the early postoperative period following kidney transplantation (KT). We described congestion changes during the early postoperative period following KT and the feasibility of LUS in this setting. MethodsLUS (28 scanning-points method) and inferior vena cava (IVC) measurements were routinely performed in 36 patients after KT. Estimated plasma volume (ePV) was calculated from hemoglobin and hematocrit levels. ResultsNo patient had >15 B-lines during the hospital stay. B-lines slightly increased until Day 4 after KT (Day 1, 1.7 ± 1.7; Day 4, 2.5 ± 2.5) and decreased up to Day 10 (1.4 ± 2.2; P vs Day 4 <.05). More B-lines were observed in patients aged older than 60 (P = .01 at Day 4) whereas IVC diameter and ePV were similar. In patients older than 60, B-lines had weak correlation with body weight variation (r = 0.64; P < .05), IVC diameters (r = 0.59 at Day 4 and r = 0.58 at Day 10; P < .05) but a strong correlation with ePV (r = 0.93 at Day 14; P < .05). B-line changes from Day 1 to Day 10 correlated with IVC diameter changes (r = 0.62; P < .05). ConclusionLUS identifies subtle congestion changes during the early postoperative period following KT. The hyperhydration strategy usually followed during this period does not result in overt pulmonary congestion as assessed by LUS, even in older recipients.

Hemodynamic effects of noninvasive positive-pressure ventilation assessed using transthoracic echocardiography

Aims:The aim of this study is to measure the effect of positive-pressure ventilation on heart chamber dimensions, left ventricular (LV) systolic function, LV diastolic function, right ventricular (RV) systolic function, and RV pressure using transthoracic echocardiography.Settings and Design:This is a prospective study in a single secondary health-care center.Materials and Methods:A total of 107 patients with obstructive sleep apnea on continuous positive airway pressure (CPAP) therapy were recruited as participants between April and September 2016. Transthoracic echocardiography was performed twice on each participant, before and 15 min after, they used their own CPAP machines, and the echocardiography parameters of both scans were compared.Statistical Analysis Used:The parametric paired t-test was used to compare heart chamber dimensions, left heart diastolic function, left heart systolic function, right heart systolic function, and right heart pressure effect, without and with CPAP. These data were further examined among several subgroups defined by CPAP when the cutoff point was set at 8 cmH2O and 10 cmH2O. The level of significance was set at 0.05. Statistical analyses were performed using IBM SPSS version 22 (IBM, Armonk, NY, USA).Results:There were statistically significant reductions, after the application of CPAP, in the heart dimensions, and LV and RV systolic function. There were no significant changes in diastolic function. Concerning right heart pressure, with CPAP, there was a significant increase in the inferior vena cava (IVC) diameter and there was also a significant decrease in IVC variability from 44.56% ± 14.86% to 36.12% ± 11.42%. The maximum velocity of tricuspid regurgitation (TR) decreased significantly from 180.66 ± 6.95 cm/s to 142.30 ± 52.73 cm/s. Such changes were observed in both low and high CPAP subgroups.Conclusions:When placed on positive pressure, the clinically significant change in IVC diameter and variability and change in trans-TR velocity mean that it would be inaccurate to predict right heart chamber pressure through echocardiogram. Alternative methods for predicting right heart pressure are recommended.

Ultrasound assessment of volume responsiveness in critically ill surgical patients: Two measurements are better than one.

The intended physiologic response to a fluid bolus is an increase in stroke volume (SV). Several ultrasound (US) measures have been shown to be predictive. The best measure(s) in critically ill surgical patients remains unclear. This is a prospective observational study in critically ill surgical patients receiving a bolus of crystalloid, colloid or blood. A transthoracic echocardiogram was performed before (pre-transthoracic echocardiogram) and after. A positive volume response (+VR) was defined as a ≥15% increase in SV. Predictive measures were: left ventricular velocity time integral (VTI), respiratory SV variation (rSVV), passive leg raise SVV (plr SVV), positional internal jugular (IJ) vein change (0-90 degrees) and respiratory variation in the IJ sitting upright (90 degrees IJ). For each measure the area under the receiver operating curve (AUROC) was assessed and the best measure(s) determined. Between November 2013 and November 2015, 199 patients completed the study. After the pilot analyses, plr SVV was abandoned because it could not be reliably assessed. VTI, rv 90 degrees IJ, 0 degree to 90 degrees IJ, were all significantly associated with VR (p < 0.05), rSVV and rv inferior vena cava were not. For VTI AUROC was 0.71 (95% confidence interval [CI], 0.64-0.77). For rv 90 degrees, it was 0.65 (95% CI, 0.57-0.71), and 0.61 (95% CI, 0.54-0.69) for 0 degrees to 90 degrees IJ. When VTI and rv 90 degrees were considered together, the AUROC rose to 0.76 (95% CI, 0.69-0.82) for the population as a whole and 0.78 (95% CI, 0.69-0.85) in mechanically ventilated patients. The positive predictive value for combined assessment was 80% and the negative 70%. In a clinically relevant heterogeneous population, US is moderately predictive of VR. Inferior vena cava diameter change is not predictive. IJ change and VTI are the best measures, especially when used together. Future work should focus on combination metrics and the IJ. Diagnostic test, level II.

Dynamic Limb Bioimpedance and Inferior Vena Cava Ultrasound in Patients Undergoing Hemodialysis.

Assessment of volume status in critically ill patients poses a challenge to clinicians. Measuring changes in the inferior vena cava (IVC) diameter using ultrasound is becoming a standard tool to assess volume status. Ultrasound requires physicians with significant training and specialized expensive equipment. It would be of significant value to be able to obtain this measurement continuously without physician presence. We hypothesize that dynamic changes in limb's bioimpedance in response to respiration could be used to predict changes in IVC. Forty-six subjects were tested a hemodialysis session. Impedance was measured via electrodes placed on the arm. Simultaneously, the IVC diameter was assessed by ultrasound. Subjects were asked to breathe spontaneously and perform respiratory maneuvers using a respiratory training device. Impedance (dz) was determined and compared with change in IVC diameter (dIVC; r = 0.76, p < 0.0001). There was significant relationship between dz and dIVC (p< 0.0001). Receiver-operator curves for dz at thresholds of dIVC (20% to70%) demonstrated high predictive power with areas under the curves (0.87-0.99, p < 0.0001). This evaluation suggests that real-time dynamic changes in limb impedance are capable of tracking a wide range of dynamic dIVC. This technique might be a suitable surrogate for monitoring real-time changes in dIVC to assess intravascular volume status.

Effect of Inhalational Anesthetics and Positive-pressure Ventilation on Ultrasound Assessment of the Great Vessels: A Prospective Study at a Children's Hospital.

Bedside ultrasound has emerged as a rapid, noninvasive tool for assessment and monitoring of fluid status in children. The inferior vena cava (IVC) varies in size with changes in blood volume and intrathoracic pressure, but the magnitude of change to the IVC with inhalational anesthetic and positive-pressure ventilation (PPV) is unknown. Prospective observational study of 24 healthy children aged 1 to 12 yr scheduled for elective surgery. Ultrasound images of the IVC and aorta were recorded at five time points: awake; spontaneous ventilation with sevoflurane by mask; intubated with peak inspiratory pressure/positive end-expiratory pressure of 15/0, 20/5, and 25/10 cm H2O. A blinded investigator measured IVC/aorta ratios (IVC/Ao) and changes in IVC diameter due to respiratory variation (IVC-RV) from the recorded videos. Inhalational anesthetic decreased IVC/Ao (1.1 ± 0.3 vs. 0.6 ± 0.2; P < 0.001) but did not change IVC-RV (median, 43%; interquartile range [IQR], 36 to 58% vs. 46%; IQR, 36 to 66%; P > 0.99). The initiation of PPV increased IVC/Ao (0.64 ± 0.21 vs. 1.16 ± 0.27; P < 0.001) and decreased IVC-RV (median, 46%; IQR, 36 to 66% vs. 9%; IQR, 4 to 14%; P < 0.001). There was no change in either IVC/Ao or IVC-RV with subsequent incremental increases in peak inspiratory pressure/positive end-expiratory pressure (P > 0.99 for both). Addition of inhalational anesthetic affects IVC/Ao but not IVC-RV, and significant changes in IVC/Ao and IVC-RV occur with initiation of PPV in healthy children. Clinicians should be aware of these expected vascular changes when managing patients. Establishing these IVC parameters will enable future studies to better evaluate these measurements as tools for diagnosing hypovolemia or predicting fluid responsiveness.

Prospective analysis of cardiac collapsibility of inferior vena cava using ultrasonography

PurposeThe inferior vena cava (IVC) diameter and its respiratory change (respiratory variation) reportedly correlate well with the central venous pressure and response to fluid. However, changes in the IVC diameter are related to the cardiac rhythm (cardiac variation), which can be useful as an indicator for intravascular volume but can affect respiratory variation. We conducted a prospective analysis of this cardiac variation in adult emergency department patients. MethodsUltrasonographic IVC images from 190 consecutive adult emergency department patients were collected prospectively. The IVC diameters 2 cm caudal from the middle hepatic vein were tracked automatically and measured. The IVC diameter changes were analyzed using a software program that tracks 2-dimensional motion in B-mode images. Cardiac and respiratory variations were calculated and analyzed. ResultsThe average IVC cardiac variation was 11.0% (95% confidence interval, 9.8%-12.3%) in these patients, which affects the respiratory variation resulting in 1.68-fold higher overestimation of respiratory variation. The coefficient of correlation between IVC cardiac variations and respiratory variations was 0.34 (P < .05). ConclusionsThe IVC cardiac variation affects our interpretation of ultrasonography IVC imaging. The IVC cardiac variation provides several advantages over other parameters of intravascular volume. Therefore, it can be a novel tool to assess the intravascular volume of the patients.

The role of inferior vena cava diameter in volume status monitoring; the best sonographic measurement method?

ObjectivesThis study aims to determine the site of and the best sonographic method for measurement of inferior vena cava (IVC) diameter in volume status monitoring. MethodsThis observational before-and-after study was performed at the intensive care unit of the emergency department. It included hypotensive adult patients with suspected sepsis who were recommended to receive at least 20 mg/kg fluid replacement by the emergency physician. The patients were fluid replaced at a rate of 1000 mL/h, and maximum and minimum IVC diameters were measured and the Caval index calculated sonographically via both B-mode and M-mode. Hence, IVC’s volume response was assessed by a total of 6 parameters, 3 each in M-mode and B-mode. Freidman test was used to assess the change in IVC diameter with fluid replacement. Wilcoxon test with Bonferroni correction was used to determine which measurement method more sensitively measured IVC diameter change. ResultsTwenty-eight patients with a mean age of 71.3 were included in the final analysis.The IVC diameter change was significant with all 6 methods (P < .001). The IVC minimum diameter change measured on M-mode during inspiration (M-mode i) was the only measurement method that significantly showed diameter change with each 500-mL fluid replacements. The initial and the subsequent M-mode i values after each 500 mL of fluid were 5.65 ± 3.34; 8.05 ± 3.66; 10.16 ± 3.61, and 11.21 ± 2.94, respectively (P < .001, P < .002, and P < .003, respectively). ConclusionInferior vena cava diameter was changed by fluid administration. The M-mode i method that most sensitively measures that change may be the most successful method in volume status monitoring.

Inferior vena cava diameter change after intravenous furosemide in patients diagnosed with acute decompensated heart failure.

Measurement of the inferior vena cava (IVC) diameters may improve decision-making for patients hospitalized with acute decompensated heart failure. Nevertheless, little is known about how the IVC is affected by loop diuretics. We sought to determine if bolus infusions of intravenous furosemide affect IVC diameters measured by hand-carried ultrasonography. We conducted a prospective cohort study at a public teaching hospital from September 2009 through June 2010. Physician investigators performed IVC ultrasonography on a convenience sample of 70 hospitalized adults who were prescribed intravenous furosemide for the diagnosis of acute decompensated heart failure. Participants' median baseline IVC diameter was 2.38 cm (interquartile range, 1.91-2.55 cm). At 1-2 hours after furosemide, IVC diameters decreased an average of 0.21 cm (95% CI, 0.13-0.29 cm) and remained significantly below baseline at 2-3 hours after furosemide by an average of 0.15 cm (95% CI, 0.07-0.22 cm). IVC diameters of adults diagnosed with acute decompensated heart failure become measurably smaller after single doses of intravenous furosemide. Whether this represents a true change in volume status has not been studied.

Systemic Venous Diameters, Collapsibility Indices, and Right Atrial Measurements in Normal Pediatric Subjects

Compromise of right heart function is an important feature of many forms of congenital heart disease, and right atrial (RA) pressure is clinically relevant. Inferior vena cava (IVC) diameter and inspiratory collapse are indices of RA pressure, but pediatric data are lacking. RA measurements, systemic venous diameters, and Doppler filling fractions were prospectively investigated in healthy volunteer children and adolescents. The IVC was measured in its long axis just above the junction with the hepatic veins in the subxiphoid view and the superior vena cava at its junction with the right atrium in the right parasternal view. The changes in IVC diameter (IVCD) during quiet respiration and with a sniff were recorded. Hepatic venous systolic filling fraction was calculated from Doppler velocities in the first hepatic vein. RA major-axis length, area, and volume were measured from the apical four-chamber view. Three measurements of each parameter were averaged over at least three respiratory cycles. The IVC collapsibility index (IVCCI) was calculated as [(IVCDmax - IVCDmin)/IVCDmax] × 100. Substituting IVCDsniff for IVCDmin in the formula, the IVCCIsniff was calculated. Of 132 subjects enrolled, data in 120 (mean age, 8.3 ± 4.5 years) were analyzed. The maximal (expiratory) and minimal (inspiratory) diameters during free breathing were 12.1 ± 3.8 and 8.9 ± 3.8 mm for the IVC and 11.9 ± 3.4 and 7.9 ± 2.6 mm for the superior vena cava. IVCCImin and IVCCIsniff were 30 ± 13 and 47 ± 18, respectively. The RA major-axis length, area, and indexed maximal volume were 3.7 ± 0.7cm, 10.3 ± 3.6 cm(2), and 22.3 ± 7.0 mL/m(2), respectively. Correlations of maximal superior vena cava and IVC dimensions with bodysurface area were slightly better than with age and much stronger than withRA volume. No significant correlation was found between IVCCIs and age, gender, or indexed RA volume. Measurement of systemic venous diameters, collapsibility indices, and RA volumes is feasible inhealthy children and adolescents. Venous diameters increase predictably with growth and so must be interpreted in light of body surface area. IVCCIs and hepatic venous filling fraction compare closely with those reported in adults. Pediatric nomograms for these parameters are provided, and they should next be evaluated for relation to directly measured RA pressure in this age group.

Echocardiographic Changes During Treatment of Acute Decompensated Heart Failure: Insights From the ESCAPE Trial

BackgroundLong-term heart failure (HF) treatment has been shown to result in reverse chamber remodeling. However, it is unknown whether sizes of cardiac chambers acutely change during HF therapy and whether these changes are associated with favorable clinical outcomes. Methods and ResultsUsing the Evaluation Study of Congestive Heart Failure and Pulsmonary Artery Catheterization Effectiveness (ESCAPE) trial database, echocardiographic parameters at baseline and discharge, changes from baseline to discharge, and their association with the combined endpoint of death or HF rehospitalization (HFH) at 6 months were evaluated in patients admitted with acute decompensated HF (ADHF). Also, the correlation between changes in invasive hemodynamic parameters compared with changes in echocardiographic parameters was analyzed. During the treatment of ADHF, right atrium, right ventricle, and inferior vena cava (IVC) sizes decreased acutely. Mitral regurgitation severity and mitral inflow parameters also improved significantly. However, the majority of acute changes in echocardiographic parameters did not have an impact on clinical outcome, except for the reduction in left ventricular (LV) end-diastolic and end-systolic volumes, which was associated with a reduction in the combined outcome of HFH or death. The change in invasive hemodynamics that best correlated with change in echocardiographic parameters was change in pulmonary capillary wedge pressure with change in IVC diameter and IVC collapsibility. ConclusionsThis is the first study to identify the echocardiographic parameters that change during the treatment of ADHF and the echocardiographic parameters that most reliably correlate with invasive hemodynamic changes. Most changes in echocardiographic parameters were not associated with clinical outcomes, except for the reduction in LV volume, which was associated with a reduction in HFH or death.

Age-Related Decrease in Inferior Vena Cava Diameter Measured with Echocardiography

The diameter of the inferior vena cava (IVC) measured with echocardiography is clinically used as a parameter to estimate right atrial pressure, which reflects dehydration or overhydration. Because elderly patients fall easily into dehydration, normal values for IVC diameters in elderly patients may be helpful for geriatric medicine. However, normal values of IVC diameter in relation to age have not been investigated. The purpose of this study was to elucidate age-related changes in IVC diameter using echocardiography. Enrolled in the study were 200 patients (67 ± 15 yrs: range 17-94 yrs) with cardiovascular risk factors but no overt cardiac diseases. IVC diameters throughout the respiratory cycle were measured as maximum and minimum IVC diameters (IVC(max), IVC(min)) using M-mode echocardiography. To assess IVC collapsibility, the respirophasic variation of IVC diameter was calculated as (IVC(max) - IVC(min))/(IVC(max)) ×100. Maximum IVC diameter was decreased with advancing age (r = -0.221, p = 0.002). The respirophasic variation of the IVC diameter was increased with advancing age (r = 0.244, p = 0.001). Stepwise multiple regression analysis showed that age was an independent determinant for both maximum IVC diameter (ß coefficient = -0.249, p < 0.001) and respirophasic variation of the IVC diameter (ß coefficient = 0.268, p < 0.001). Age-related decrease in maximum IVC diameter and increase in the respirophasic IVC collapsibility may indicate the decrease in right atrial pressure in some elderly patients. Therefore, elderly patients with decreased maximum IVC and increased respirophasic IVC collapsibility may need prevention for dehydration.