Inferior vena cava diameter and central venous pressure correlation during cardiac surgery

The Flatness Index of Inferior Vena Cava can be an Accurate Predictor for Hypovolemia in Multi-Trauma Patients

INTRODUCTION

Shock is the leading cause of death in multi-trauma patients and must be detected at an early stage to improve prognosis. Many parameters are used to predict clinical condition and outcome in trauma. Computed tomography (CT) signs of hypovolemic shock in trauma patients are not clear yet, requiring further research. The flatness index of inferior vena cava (IVC) is a helpful method for this purpose.

METHODS

This is a prospective, cross-sectional study which included adult multi-trauma patients (>18 years) who were admitted to the emergency department (ED) and underwent a thoraco-abdominal CT from 2017 through 2018. The main objective of this study was to investigate whether the flatness index of IVC can be used to determine the hypovolemic shock at an early stage in multi-trauma patients, and to establish its relations with shock parameters. The patients' demographic features, trauma mechanisms, vitals, laboratory values, shock parameters, and clinical outcome within 24 hours of admission were recorded.

RESULTS

Total of 327 (229 males with an average age of 40.9 [SD = 7.93]) patients were included in the study. There was no significant difference in the flatness index of IVC within genders (P = .134) and trauma mechanisms (P = .701); however, the flatness index of IVC was significantly higher in hypotensive (systolic blood pressure [SBP] ≤90 mmHg and/or diastolic blood pressure [DBP] ≤60 mmHg; P = .015 and P = .019), tachycardic (P = .049), and hypoxic (SpO2 ≤%94; P <.001) patients. The flatness index of IVC was also higher in patients with lactate ≥ 2mmol/l (P = .043) and patients with Class III hemorrhage (P = .003). A positive correlation was determined between lactate level and the flatness index of IVC; a negative correlation was found between Glasgow Coma Scale (GCS) and Revised Trauma Score (RTS) with the flatness index of IVC (for each of them, P <.05).

CONCLUSION

The flatness index of IVC may be a useful method to determine the hypovolemic shock at an early stage in multi-trauma patients.

Goal-directed fluid therapy using transoesophageal echocardiographic inferior venacaval index in patients with low left ventricular ejection fraction undergoing major cytoreductive surgery: A clinical trial

Background and Aims:

This study aims to trans oesophageal echo cardiographically (TOE) measure inferior venacava diameter (IVCD) during inspiration and expiration in poor left ventricular ejection fraction (LVEF) patients undergoing cytoreductive oncosurgery, to ascertain if any correlation exists between, caval index (DeltaIVCD), and stroke volume variation (SVV), and to compare DeltaIVCD-guided versus SVV-guided fluid therapy.

Methods:

In this prospective, parallel group, interventional study, seventy American Society of Anesthesiologists-III patients, aged 30-75 years, weighing 40-90 kg, with LVEF ≤40% undergoing cytoreductive surgery were included and randomised to group-D (DeltaIVCD-guided fluid therapy) and group-S (SVV-guided fluid therapy). Patients with oesophageal lesions were excluded. After standard endotracheal anaesthesia, arterial and internal jugular vein catheters were placed. A TOE probe was inserted in the interventional group-D. Quantification of IVCD respiratory variations was done. Heart rate (HR), arterial oxygen saturation (SPO₂), mean arterial pressure, end tidal carbondioxide (EtCO₂), central venous pressure, SVV, IVCD, and urine output (UO) were recorded every 30 min. Post-operative arterial blood gas analysis, lung-ultrasound, chest-radiograph, and serum creatinine were done.

Statistical Analysis:

Pearson's correlation coefficient as measure of strength of linear relationship, calculation of regression equation, and unpaired t-test for normally distributed continuous variables were used.

Results:

A positive correlation between DeltaIVCD and SVV (r = 0.751) was observed. A regression equation was obtained for SVV (SVV = [0.317 × DeltaIVCD] + 5.877). Serum lactate, estimated glomerular filtration rate, HR, and UO were within normal limits in group-D. There was no pulmonary oedema.

Conclusion:

DeltaIVCD-guided intravenous fluid therapy is valuable in low LVEF patients where tight fluid control is essential and any fluid overload may precipitate cardiac failure.

Quantitative Time-Harmonic Ultrasound Elastography of the Abdominal Aorta and Inferior Vena Cava

The purpose of this study was to evaluate the sensitivity of quantitative time-harmonic ultrasound elastography (THE) of the inferior vena cava (IVC) and abdominal aorta (AA) to changes in central volume status. THE of the IVC and AA was performed in 20 healthy volunteers before and after oral intake of 1 L of water and before or during passive leg raising to augment venous filling. Compound maps of shear wave speed (SWS) as surrogate measures of vessel wall stiffness were generated within the full field of view from multifrequency harmonic wave fields. SWS was measured in regions of the IVC and AA. Blood pressure, stroke volume, cardiac output and pulse wave velocity were recorded. Statistical significance of SWS changes was tested using one-way repeated-measures analysis of variance. SWS measured in the IVC increased from 1.71 ± 0.1 m/s before water intake to 1.82 ± 0.1 m/s during passive leg raising and, further, to 1.87 ± 0.1 m/s after hydration and to 1.95 ± 0.1 m/s with hydration plus passive leg raising (p < 0.001). SWS in the AA did not change significantly after hydration (2.14 ± 0.13 m/s vs. 2.15 ± 0.16 m/s; p = 0.792). SWS was significantly higher in the AA than in the IVC across all experiments (p < 0.001). Water drinking did not significantly influence blood pressure, pulse wave velocity and cardiac output (all p values >0.1), whereas stroke volume increased significantly (p = 0.031). Time-harmonic ultrasound elastography enables quantification of the wall stiffness of the large abdominal vessels and is sensitive to different volume and pressure states in the IVC.

Tricuspid annular plane systolic excursion and central venous pressure in mechanically ventilated critically ill patients

Background

The tricuspid annular plane systolic excursion (TAPSE) is commonly recommended for estimating the right ventricular systolic function. The central venous pressure (CVP), which is determined by venous return and right heart function, was found to be associated with right ventricular outflow fractional shortening. This study thus aimed to investigate the relationship between the TAPSE and CVP in mechanically ventilated critically ill patients.

Methods

This is a prospective observational study. From October 1 to December 31, 2017, patients admitted to the intensive care unit with CVP monitoring and controlled mechanical ventilation were screened for enrolment. Echocardiographic parameters, including the TAPSE, mitral annular plane systolic excursion (MAPSE), left ventricular ejection fraction (LVEF), and internal diameter of inferior vena cava (dIVC), and haemodynamic parameters, including the CVP, were collected.

Results

Seventy-four patients were included. Thirty-one were included in the low LVEF (< 55%) group, and 43 were included in the high LVEF (≥55%) group. In the high LVEF group, the TAPSE and CVP were not correlated (r = − 0.234, P = 0.151). In the low LVEF group, partial correlation analysis indicated that the TAPSE and CVP were correlated (r = − 0.516, P = 0.006), and multivariable linear regression analysis indicated that the TAPSE was independently associated with the CVP (standard coefficient: − 0.601, p < 0.001). Additionally, in the low LVEF group, a ROC analysis showed that the area under the curve of the TAPSE for the detection of CVP greater than 8 mmHg was 0.860 (95% confidence interval: 0.730–0.991; P = 0.001). The optimum cut-off value was 1.52 cm, which resulted in a sensitivity of 75.0%, a specificity of 86.7%, a positive predictive value of 84.6% and a negative predictive value of 77.8%.

Conclusions

The TAPSE is inversely correlated with the CVP in mechanically ventilated critically ill patients who have a LVEF less than 55%.

A Non-invasive Method for Assessment of Intravascular Fluid Status: Inferior Vena Cava Diameters and Collapsibility Index

Objective:

To evaluate the correlation between central venous pressure (CVP) and inferior vena cava (IVC) diameters measured by ultrasonography (Ultrasound) in critically ill patients.

Methods:

Intubated critically ill patients were enrolled. The CVP values were measured using a U-tube manometer and were compared to the IVC diameters and collapsibility index, which were measured by bedside Ultrasound. Patients younger than 18 years old, who were not intubated, who had an abdominal pressure greater than 12 mmHg, and/or who were admitted for trauma were excluded from the study.

Results:

Eighty three patients with a mean age of 73.6±11.2 years were enrolled. The most common diagnosis was sepsis (21 patients, 25.30%). IVC inspiration measurements were statistically significantly correlated with CVP measurements (p0.05, r: 0.1). IVC collapsibility measurements showed a negative correlation with CVP measurements (p<0.01, r: 0.68).

Conclusions:

There is a strong correlation between CVP and IVC diameters and the collapsibility index. This is a new formula for evaluating CVP, based on our statistical analyses.

The efficacy of sonographic measurement of inferior vena cava diameter as an estimate of central venous pressure

BACKGROUND

Central venous pressure (CVP) and right atrial pressure (RAP) are important parameters in the complete hemodynamic assessment of a patient. Sonographic measurement of the inferior vena cava (IVC) diameter is a non-invasive method of estimating these parameters, but there are limited data summarizing its diagnostic accuracy across multiple studies. We performed a comprehensive review of the existing literature to examine the diagnostic accuracy and clinical utility of sonographic measurement of IVC diameter as a method for assessing CVP and RAP.

METHODS

We performed a systematic search using PubMed of clinical studies comparing sonographic evaluation of IVC diameter and collapsibility against gold standard measurements of CVP and RAP. We included clinical studies that were performed in adults, used current imaging techniques, and were published in English.

RESULTS

Twenty one clinical studies were identified that compared sonographic assessment of IVC diameter with CVP and RAP and met all inclusion criteria. Despite substantial heterogeneity in measurement techniques and patient populations, most studies demonstrated moderate strength correlations between measurements of IVC diameter and collapsibility and CVP or RAP, but more favorable diagnostic accuracy using pre-specified cut points. Findings were inconsistent among mechanically ventilated patients, except in the absence of positive end-expiratory pressure.

CONCLUSION

Sonographic measurement of IVC diameter and collapsibility is a valid method of estimating CVP and RAP. Given the ease, safety, and availability of this non-invasive technique, broader adoption and application of this method in clinical settings is warranted.

The evaluation of cardiac tamponade risk in patients with pericardial effusion detected by non-gated chest CT

BACKGROUND

Although pericardial effusion is often identified using non-gated chest computed tomography (CT), findings predictive of cardiac tamponade have not been adequately established.

PURPOSE

To determine the findings predictive of clinical cardiac tamponade in patients with moderate to large pericardial effusion using non-gated chest CT.

MATERIAL AND METHODS

We performed a retrospective analysis of 134 patients with moderate to large pericardial effusion who were identified from among 4581 patients who underwent non-gated chest CT. Cardiac structural changes, including right ventricular outflow tract (RVOT), were qualitatively evaluated. The inferior vena cava ratio with hepatic (IVCupp) and renal portions (IVClow) and effusion size were measured. The diagnostic performance of each structural change was calculated, and multivariate analysis was used to determine the predictors of cardiac tamponade.

RESULTS

Of the 134 patients (mean age, 70.3 years; 64 men), 37 (28%) had cardiac tamponade. The sensitivity and specificity were 76% and 74% for RVOT compression; 87% and 84% for an IVClow ratio ≥0.77; and 60% and 77% for an effusion size ≥25.5 mm, respectively. Multivariate logistic regression analysis demonstrated that RVOT compression, an IVClow ratio ≥0.77, and an effusion size ≥25.5 mm were independent predictors of cardiac tamponade. The combination of these three CT findings had a sensitivity, specificity, and accuracy of 81%, 95%, and 91%, respectively.

CONCLUSION

In patients with moderate to large pericardial effusion, non-gated chest CT provides additional information for predicting cardiac tamponade.

Echocardiographic characteristics of patients with acute heart failure requiring tolvaptan: a retrospective study

BACKGROUND

No study has investigated the admission echocardiographic characteristics of acute heart failure (AHF) patients who are resistant to conventional diuretics and require tolvaptan.

METHODS

We retrospectively analyzed the echocardiographic characteristics of AHF patients who were resistant to conventional diuretics and took tolvaptan (tolvaptan group: 26 patients), and compared them to those who were sensitive to conventional diuretics (conventional group: 180 patients).

RESULTS

The tolvaptan group had a higher left atrial volume index (96.0 ± 85.0 mL/m2 vs. 45.8 ± 25.9 mL/m2, p < 0.0001), maximum inferior vena cava diameter (20.7 ± 6.9 mm vs. 18.1 ± 4.2 mm, p < 0.01), and higher tricuspid regurgitation grade (1.1 ± 0.8 vs. 0.8 ± 0.6, p < 0.05) than the conventional group. However, the left ventricular ejection fraction and end diastolic diameter were similar between the groups. Responders of tolvaptan had no significant echocardiographic differences compared to the non-responders.

CONCLUSIONS

The admission echocardiographic characteristics of AHF patients requiring tolvaptan included a larger left atrium, inferior vena cava, and more severe tricuspid regurgitation. Echocardiography may provide useful information for the early and appropriate initiation of tolvaptan.

The relationship between inferior vena cava diameter measured by bedside ultrasonography and central venous pressure value

Objective: We aimed to present inferior vena cava (IVC) diameter as a guiding method for detection of relationship between IVC diameter measured noninvasively with the help of ultrasonography (USG) and central venous pressure (CVP) and evaluation of patient's intravascular volume status.

Methods: Patients over the age of 18, to whom a central venous catheter was inserted to their subclavian vein or internal jugular vein were included in our study. IVC diameter measurements were recorded in millimeters following measurement by the same clinician with the help of USG both at the end-inspiratory and end-expiratory phase. CVP measurements were viewed on the monitor by means of piezoelectric transducer and recorded in mmHg. SPSS 18.0 package program was used for statistical analysis of data.

Results: Forty five patients were included in the study. The patients had the diagnosis of malignancy (35.6%), sepsis (13.3%), pneumonia, asthma, chronic obstructive pulmonary disease (11.1%). 11 patients (24.4%) required mechanical ventilation while 34 (75.6%) patients had spontaneous respiration. In patients with spontaneous respiration, a significant relationship was found between IVC diameters measured by ultrasonography at the end of expiratory and inspiratory phases and measured CVP values at the same phases (for expiratory p = 0.002, for inspiratory p= 0.001). There was no statistically significant association between IVC diameters measured by ultrasonography at the end of expiration and inspiration and measured CVP values at the same phases in mechanically ventilated patients.

Conclusions: IVC diameter measured by bedside ultrasonography can be used for determination of the intravascular volume status of the patients with spontaneous respiration.

Alternative methods to central venous pressure for assessing volume status in critically ill patients

INTRODUCTION

Early goal-directed therapy increases survival in persons with sepsis but requires placement of a central line. We evaluate alternative methods to measuring central venous pressure (CVP) to assess volume status, including peripheral venous pressure (PVP) and stroke volume variation (SVV), which may facilitate nurse-driven resuscitation protocols.

METHODS

Patients were enrolled in the emergency department or ICU of an academic medical center. Measurements of CVP, PVP, SVV, shoulder and elbow position, and dichotomous variables Awake, Movement, and Vented were measured and recorded 7 times during a 1-hour period. Regression analysis was used to predict CVP from PVP and/or SVV, shoulder/elbow position, and dichotomous variables.

RESULTS

Twenty patients were enrolled, of which 20 had PVP measurements and 11 also had SVV measurements. Multiple regression analysis demonstrated significant predictive relationships for CVP using PVP (CVP = 6.7701 + 0.2312 × PVP - 0.1288 × Shoulder + 12.127 × Movement - 4.4805 × Neck line), SVV (CVP = 14.578 - 0.3951 × SVV + 18.113 × Movement), and SVV and PVP (CVP = 4.2997 - 1.1675 × SVV + 0.3866 × PVP + 18.246 × Awake + 0.1467 × Shoulder = 0.4525 × Elbow + 15.472 × Foot line + 10.202 × Arm line).

DISCUSSION

PVP and SVV are moderately good predictors of CVP. Combining PVP and SVV and adding variables related to body position, movement, ventilation, and sleep/wake state further improves the predictive value of the model. The models illustrate the importance of standardizing patient position, minimizing movement, and placing intravenous lines proximally in the upper extremity or neck.

Demonstration of inferior vena cava compression by probe pressure during subxiphoid echocardiography

We sought to compare the inferior vena cava diameter measured by transthoracic echocardiography and by transesophageal echocardiography in human and animals. Transthoracic echocardiography yielded lower inferior vena cava diameter values than transesophageal echocardiography. Adult and pediatric intensivists should pay attention to the risk of false measurement of the inferior vena cava anterior-posterior diameter that may be due to compression of the inferior vena cava by the sonographic probe when the subxiphoid view is used.

Histological basis of the liver hanging maneuver

BACKGROUND

Liver hanging maneuver (LHM) consists in passing a tape between the retrohepatic inferior vena cava (RHIVC) and the liver to perform various kinds of hepatectomies. LHM is a well-known procedure but its histological basis remains poorly documented.

METHODS

Ten anatomical specimens comprising RHIVC, and surrounding hepatic parenchyma were studied after conventional staining and immunohistochemistry with specific antibody for alpha smooth muscle actin.

RESULTS

RHIVC wall structure consists of a thick muscular layer of longitudinal smooth muscle fibers and a peripheral loose connective tissue without smooth muscle fibers adherent to the liver parenchyma. This loose connective tissue between the liver and the RHIVC is the avascular plane for the passage of the clamp during LHM.

CONCLUSION

The histological structure of the RHIVC does not seem to have any special hemostatic property. The low bleeding rate during LHM can be only explained by the very low density of RHIVC afferent veins.