Comparison of sonographic inferior vena cava and aorta indexes during fluid administered in children

Accuracy of Respiratory Variation in Inferior Vena Cava Diameter to Predict Fluid Responsiveness in Children Under Mechanical Ventilation

Proper assessment of fluid responsiveness using accurate predictors is crucial to guide fluid therapy and avoid the serious adverse effects of fluid overload. The main objective of this study was to investigate the accuracy of respiratory variations in inferior vena cava diameter (∆IVC) to predict fluid responsiveness in mechanically ventilated children. This prospective single-center study included 32 children (median age and weight of 17 months and 10 kg, respectively) who received a fluid infusion of 10 ml kg-1 of crystalloid solutions over 10 min. ∆IVC and respiratory variation in aortic blood flow peak velocity (∆Vpeak) were determined over one controlled respiratory cycle before and after fluid loading. Thirteen (41%) participants were fluid-responders. ∆IVC, ∆Vpeak, stroke volume index, and cardiac index were found to be predictors of fluid responsiveness. However, the area under the ROC curve of ∆IVC was smaller when compared to ∆Vpeak (0.709 vs. 0.935, p < 0.012). The best cut-off values were 7.7% for ∆IVC (sensitivity, 69.2%; specificity 78.9%, positive predictive value, 69.2%; and negative predictive value, 78.9%) and 18.2% for ∆Vpeak (sensitivity, 84.6%; specificity, 89.5%; positive predictive value, 84.6%; negative predictive value, 89.5%). Changes in stroke volume were positively correlated with ∆IVC (ρ = 0.566, p < 0.001) and ∆Vpeak (ρ = 0.603, p < 0.001). A significant correlation was also found between changes in MAP and ∆Vpeak (ρ = 0.382; p = 0.031), but the same was not observed with ∆IVC (ρ = 0.011; p = 0.951). In conclusion, ∆IVC was found to have a moderate accuracy in predicting fluid responsiveness in mechanically ventilated children and is an inferior predictor when compared to ∆Vpeak.

Evaluation of the Caval aortic index in fetal growth restriction: A case-control study in a tertiary center

OBJECTIVE

To examine the inferior vena cava (IVC) diameter, aortic diameter, and caval aortic index in fetuses with growth restriction and to compare the findings with fetuses from uncomplicated pregnancies at similar gestational weeks.

METHODS

This prospective study was conducted with a total of 176 pregnant women. According to the diagnostic criteria, 84 pregnancies diagnosed with fetal growth restriction (FGR) were compared with a control group of 92 uncomplicated pregnancies at similar gestational weeks.

RESULTS

The aortic and IVC diameter values were significantly lower in the FGR group (P < 0.001), whereas the caval aortic index was similar between the two groups. The examination of the ultrasound parameters of the cases with FGR according to the neonatal intensive care requirement revealed similar aortic diameter and caval aortic index values but a significantly smaller IVC diameter in the cases requiring neonatal intensive care (P = 0.022).

CONCLUSION

We determined that the aortic and IVC diameter values were smaller in the fetuses with growth restriction, but the caval aortic index was similar in the two groups. The measurement of the IVC diameter in FGR may be useful in predicting the neonatal intensive care requirements of these fetuses.

The Evolution of Cardiovascular Ultrasound: A Review of Cardiac Point-of-Care Ultrasound (POCUS) Across Specialties

The use of cardiac point-of-care ultrasound (POCUS) is now widespread in clinics, emergency departments, and all areas of the hospital. Users include medical trainees, advanced practice practitioners, and attending physicians in many specialties and sub-specialties. Opportunities to learn cardiac POCUS and requirements for training vary across specialties as does the scope of the cardiac POCUS examination. In this review, we describe both a brief history of how cardiac POCUS emerged from echocardiography and the state of the art across a variety of medical fields.

Point-of-Care Noninvasive Technology for Pediatric Dehydration Assessment

OBJECTIVE

Dehydration is a commonly encountered problem worldwide. Current clinical assessment is limited by subjectivity and limited provider training with children. The objective of this study is to investigate a new noninvasive, point-of-care technology that measures capillary refill combined with patient factors to accurately diagnose dehydration.

METHODS

This is a prospective observational study at a tertiary care children's hospital in Buenos Aires, Argentina. Patients were eligible if younger than 10 years who presented to the emergency department with vomiting and/or diarrhea whom the triage nurse deems to be potentially dehydrated. Patients had the digital capillary refill device done on presentation in addition to standard of care vital signs and weight. Patients had serial weights measured on hospital scales throughout their stay. The primary outcome was dehydration, which was calculated as a percent change in weight from admission to discharge.

RESULTS

Seventy-six children were enrolled in the study with 56 included in the final analysis. A stepwise forward method selection chose malnutrition, temperature, and systolic blood pressure for the multivariable model. The area under the curve for the final model was fair (0.7431). To further look into the utility of such a device in the home setting where blood pressure is not available often, we reran the model without systolic blood pressure. The area under the curve for the final model was 0.7269.

CONCLUSIONS

The digital capillary refill point-of-care device combined with readily available patient-specific factors may improve the ability to detect pediatric dehydration and facilitate earlier treatment or transfer to higher levels of care.

Ultrasonographical Assessment of Caudal Vena Cava Size through Different Views in Healthy Calves: A Pilot Study

Ultrasonographic measurements of the caudal vena cava (CVC) and aorta (Ao) are known as reliable tools to assess intravascular volume status in humans. The aim of this study was to evaluate the feasibility of obtaining ultrasonographical measurements of CVC and Ao in two different views, assess intra- and interobserver variability, and study the effect of sex, age, body weight, and breed on measurements in healthy calves. The diameter and area of CVC and Ao were measured by a single investigator in two anatomic sites (subxiphoid and paralumbar window) in 48 calves aged less than 60 days and then repeated 2.5 months after the first assessment. For intra- and interobserver variability assessment, CVC and Ao measurements were repeated by three observers on five randomly selected calves. CVC and Ao measurements were easily obtained in PV and more difficult to obtain in SV. CVC and Ao area in PV showed high repeatability and reproducibility. A positive correlation was highlighted between age and CVC and Ao measurements in both sites. In conclusion, CVC size assessment by point of care ultrasound can be easily performed at a paralumbar site in calves under 4 months of age and could be used to assess intravascular volume status.

Interobserver Agreement of Inferior Vena Cava Ultrasound Collapse Duration and Correlated Outcomes in Children With Dehydration

OBJECTIVE

Dehydration is a common concern in children presenting to pediatric emergency departments and other acute care settings. Ultrasound (US) of the inferior vena cava (IVC) may be a fast, noninvasive tool to gauge volume status, but its utility is unclear. Our objectives were to determine the interobserver agreement of IVC collapse and collapse duration, then correlate IVC collapse with the outcome of intravenous (IV) versus oral (PO) rehydration.

METHODS

We conducted a prospective study by enrolling patients 0 to 21 years old with emesis requiring ondansetron or diarrhea requiring IV hydration. Clinical operators interpreted US examinations in real time to determine whether the IVC was collapsed. Two blinded reviewers interpreted the US videos to determine IVC collapse and collapse duration. Cohen's kappa(κ) was calculated for reviewer-reviewer and reviewer-operator agreement. Primary outcomes were PO versus IV rehydration, and admitted versus discharged.

RESULTS

One hundred twelve patients were enrolled, and 102 had complete data for analysis. The mean age was 7.2 years with 51% female. Twenty-nine patients received IV hydration. The reviewer-operator agreement for IVC collapse was κ = 0.57 (95% confidence interval [CI], 0.38-0.75) and interreviewer agreement was κ = 0.93 (95% CI, 0.83-1.0). The interreviewer agreement for collapse duration was κ = 0.66 (95% CI, 0.51-0.82). All patients with noncollapsed IVCs tolerated PO hydration. The likelihood of receiving IV hydration was correlated with the duration of IVC collapse (P = 0.034).

CONCLUSIONS

Based on a novel dynamic measure of IVC collapse duration, children with increasing duration of IVC collapse correlated positively with the need for IV rehydration. Noncollapsing IVCs on US were associated with successful PO rehydration without need for IV fluids or emergency department revisits.

Sonographic Estimation Rather Than Quantification of Fluid Status Using Inferior Vena Cava and Other Major Vessel Parameters in a Non-Bleeding Fluid Loss and Centralization Model

Objective

A well-accepted step in emergency sonography is the estimation of a fluid deficit through Inferior Vena Cava (IVC) diameter variability with known cut-offs especially in bleeding. We sought to answer, whether a non-bleeding fluid deficit can be quantified through sonographic assessment of IVC diameter variability and related aortic parameters. Sport divers were used as human hypovolemic vasoconstriction models since immersion is known to cause relevant volume depletion through vasoconstriction and induced diuresis.

Materials and Methods

Forty-one sport divers performed 342 single and repetitive dives to account for intra- and interindividual variability and were assessed for inferior Vena Cava and neighboring aortic diameters as well as their cardiac/respiratory variations. Dive-related weight loss was measured together with sonographic vessel diameter changes inferior to the right atrium.

Results

Highest correlation with dive-related weight loss of max. 2.9 kg per an average 47 minutes dive was found with r=0.34 for the difference of IVC maximum diameter related to minimum Aortic diameter. Single or combined parameters, as well as Collapsibility Index, showed lower or no correlations. Vascular parameters were able to explain 7.5% of the variance of fluid losses, whereas interindividual effects explained 10%. The remaining 82.5% is of mixed intraindividual counterregulatory effects.

Conclusion

IVC diameter changes in immersion-induced hypovolemic centralization provides qualitative information on relevant fluid loss only. Confounding factors like inter and intraindividual variability prevent a sufficient correlation for useful quantification of the experienced non-bleeding fluid deficit in the clinical setting.

[Index from Diameter of Inferior Vena Cava and Abdominal Aorta of Newborns - A Relevant Method for Evaluation of Hypovolemia]

Hypovolemia is one of the important problems in sick neonates. Ultrasound is a safe, noninvasive diagnostic tool for the assessment of volume status. For that reason, the aim of the study was to determine normal values of the diameter of inferior vena cava (IVC), abdominal aorta (Ao) and the index IVC/Ao.

PATIENTS AND METHODS

97 healthy, term neonates were included in the study and investigated at first and third day of life. The diameter of IVC, Ao was measured and the index from IVC/Ao was estimated. Using statistics mean and median values of the parameters and correlations to birth weight were determined.

RESULTS

Diameter of Ao at first day was 6.1 (+/-0.6) mm and at third day 6.2 (+/-0.6) mm, of IVC at first day was 2.5 (+/-0.5) and at third day 2.61 (+/-0.5). The Index from diameters of IVC/Ao was evaluated at day 1 as 0.4 (+/-0.1) and day 3 as 0.4 (+/-0.1). We found a positive correlation to the birth weight. We identified a significant difference of the index in SGA and LGA - neonates (0.36 vs 0.47). Despite a significant reduced weight from first to third day in the neonates, we determined no influence on the diameter of IVC, Ao and the index IVC/Ao.

CONCLUSION

We determined normal values of diameter of IVC and Ao and the Index of IVC/Ao. It is our opinion, that it is possible to assess the intravascular volume using the index. The importance of the index can be underlined by the results in SGA-neonates. More research is needed to understand some points of the pathophysiology in SGA.

Caval Aortic Index: A Novel Tool for Fluid Assessment in Obstetric Emergencies

Background:

Uncorrected maternal hypotension occurring during obstetric emergencies may result in maternal and fetal morbidity. Fluid status of the pregnant mother is a major variable which affects the maternal hemodynamics during patient management, and there is no objective assessment tool for the same. A relatively new sonographic parameter, the inferior vena cava aorta (IVC/Ao) diameter index or caval aortic index, showed promise in this regard, and its application was studied in obstetric patients.

Methodology:

A prospective analytical study was conducted involving 50 pregnant and 50 nonpregnant women of reproductive age group. Using both subxiphoid and transhepatic views, their normal fasting caval aortic indices were determined from the ratio of mean IVC diameter to the mean aortic diameter. Descriptive and inferential statistical analyses were carried out accordingly.

Results:

Normal IVC/Ao diameter index for nonpregnant healthy women of reproductive age was 1.11 ± 0.29 in the subxiphoid view and 1.21 ± 0.33 in the transhepatic view. The difference between the two views was not statistically significant. IVC/Ao diameter index for a normal term pregnant woman was 1.03 ± 0.26, and term pregnancy does not significantly cause variation in the index.

Conclusions:

Caval aortic index is a useful noninvasive tool to assess volume status and guide fluid management in pregnant women presenting to the emergency department, and the transhepatic view is comparable to the traditional subxiphoid view for the measurement of the same.