SCCM Resource Library-Assessment of the Intravascular Fluid Volume in Children by Point-of-Care Ultrasound

Video Transcription

My name is Tara Osman, I am an Advanced Practice Registered Nurse at OSF Children's Hospital of Illinois in the Pediatric Intensive Care Unit.  Dr. Meena Hafsala, Dr. Sandeep Tripathi, and myself conducted a research study involving assessment of intravascular fluid volume in children using point-of-care ultrasound.  Despite significant advancements in medicine, assessment of intravascular volume and fluid responsiveness has remained an art rather than a science.  There have been various objective clinical scoring methods which have failed to adequately predict volume status or fluid responsiveness.  However, with the evolution of portable bedside ultrasound, there has become interest in utilizing this modality for intravascular volume status.  Various ultrasound metrics, such as emphyrovena cavicides and its variation during respirations, have been found to be accurate and reliable in predicting fluid status in adults.  Some of them have become standard of care. However, use of ultrasound for intravascular volume assessment in children has remained unproven.  This particular study was designed to assess the correlation of IBC variability and IBC aortic ratio with clinical hydration assessment.  The secondary objective was to correlate the ultrasound assessment of hydration using central venous pressure, or CBP.  This study was a prospective observational study which occurred in the Pediatric Intensive Care Unit at OSF Children's Hospital of Illinois from August 2019 to January 2021.  Exclusion criteria was children ages 1 day to 17 years. Exclusion criteria included post-op cardiac patients less than 1 week post-op due to the  heterogeneity of the cardiac morphology, as well as the potential for difficulty in obtaining images due to chest stressings or open chest.  These patients also had high potential for hemodynamic instability. ECMO patients were also excluded due to the potential difficulty in viewing their cardiac windows.  The investigators were blinded to the hydration status of the patient. Each patient enrolled was eligible for up to three studies occurring on separate calendar dates.  This slide depicts our ultrasound images of IBC, or inferior vena cava, variability which was assessed at the subcostal and the right lateral region, and therefore, collapsibility  index was calculated. We used the inferior vena cava max minus the inferior vena cava min and divided by the inferior vena cava max.  Here are two images representing the IBC aorta ratio visualized in the subcostal region in transverse view. We performed 145 ultrasounds on 72 patients.  The median age of the patients was 67 months. 41% of our ultrasounds were performed on ventilated patients, and 50% of our ultrasounds  had a central line in place measuring central venous pressure. The majority of the patients, 61%, were euvolemic, 10% were dehydrated, and 28% had fluid overload  as reported by their direct clinical providers. This table represents our demographic distribution including age, sex, body mass index, the clinical  diagnoses, as stated earlier, whether the patient had a central line, was intubated, and what their clinical dehydration status.  In patients on positive pressure, both subcostal and right lateral collapsibility index had a moderate correlation with each other with a correlation coefficient of 0.44.  In patients with central venous pressure measurement, the only significant correlation of minus 0.64 was noted in the right lateral collapsibility index.  On this table, we are showing IBC collapsibility index and IBC aortic ratio based on the clinical hydration status among patients on positive pressure and not on positive pressure.  Among spontaneously breathing patients, there was a significant difference observed in the collapsibility index at the subcostal region based on the patient's hydration status, 43%  for dehydrated, 30% for euvolemic, and 21% for fluid overloaded patients. For patients on positive pressure only, the median IBC aorta ratio had a significant difference  in the three hydration status categories, 0.68 for dehydration, 1.12 for euvolemic, and 1.28 for fluid overloaded patients.  In assessing the sensitivity and specificity of detecting clinical hydration by ultrasound, the subcostal collapsibility index had the highest AUC at 0.82 to detect dehydration  in spontaneously breathing patients with 80% sensitivity and 87% specificity for a cutoff of 40%. Our study had some limitations.  Our initial goal was to enroll 210 patients, each with the possibility of three ultrasounds, giving us a total of around 600 ultrasounds.  However, due to the COVID pandemic, research performed on patients was halted between March of 2020 and November of 2020, limiting the total number of enrolled participants.  We had a low number of spontaneously breathing patients with CVP measurements, making correlation analysis with CVP limited. We had a low number of patients who were dehydrated.  Because of the challenge in obtaining consent from patients being actively resuscitated, most of the patients whom we performed ultrasounds on were euvolemic.  We could not obtain all measures on all patients. A reliable IBC to aorta ratio could not be obtained for 25% of the patients.  Although we excluded fresh post-op cardiac surgery patients, a high proportion of our patients had a cardiac diagnosis.  Cardiac dysfunction can impact IBC variability, and our analysis did not account for cardiac function at the time of the ultrasound.  To conclude, ultrasound assessment of hydration in children remains an investigational tool with potential for further refinement.  Subcostal view performs best for IBC variability in spontaneously breathing patients, while IBC to aortic ratio is the best measure in mechanically ventilated patients.

Video Summary

In this video, Tara Osman, an advanced practice registered nurse, discusses a research study on using point-of-care ultrasound to assess intravascular fluid volume in children. The study aimed to determine the correlation between ultrasound assessments and clinical hydration assessments. They performed ultrasounds on 72 patients and found that the subcostal view was best for assessing hydration in spontaneously breathing patients, while the IBC to aortic ratio was more effective for mechanically ventilated patients. The study had limitations, including a smaller number of patients due to the COVID-19 pandemic. Overall, ultrasound assessment of hydration in children shows promise but requires further refinement.

Asset Subtitle

Pediatrics, Procedures, Cardiovascular, 2022

Asset Caption

INTRODUCTION: Inferior Vena Cava (IVC) variability with respirations to assess dehydration has attained recognition in adults; however, there is inconclusive evidence for various dynamic parameters in predicting fluid responsiveness in children. This study was designed to assess the correlation of IVC variability and IVC/aortic ratio with clinical hydration assessment. The secondary objective was to correlate the ultrasound assessment of hydration with central venous pressure (CVP). METHODS: Prospective observational study in PICU (08/19 to 01/21) and included all children ( < 18 years) recruited after informed consent. IVC variability was assessed at the sub-costal (S.C.), and right lateral (R.L.) region and collapsibility index (C.I) (IVC max-IVC min/IVC Max) was calculated. IVC/Aortic ratio assessed in S.C. region in transverse view. Investigators were blinded to the hydration status of the patient. Up to 3 studies per enrolled patient on separate days. RESULTS: 145 ultrasounds were performed on 72 patients (median age of 67 months). 41% (n= 60) of the ultrasounds were performed on ventilated patients and 50% (n= 72) had central line in place. The majority (61%) were euvolemic, 10% were dehydrated, and 28% had fluid overload. Among spontaneously breathing patients, a significant difference was only observed in the median C.I at the S.C region based on hydration status (43% [IQR 39%, 52%], 30% [IQR 22%, 35%] and 21% [IQR 17%, 30%] for dehydrated, euvolemic and fluid overload patients, p < 0.01). For patients on positive pressure only median IVC/aortic ratio had a significant difference (0.68 [IQR 0.60, 1.3], 1.12 [IQR 0.94, 1.33] and 1.28 [IQR 1.2, 1.5] for the 3-hydration status). SC C.I also had the highest AUC (0.82) to detect dehydration in spontaneously breathing patients, with 80% sensitivity and 87% specificity for a cut-off of 40%. Both SC and R.L. C.I had a moderate correlation with each other (correlation coefficient 0.44 (95% CI 0.17, 0.65). Only significant correlation of CI was noted for R.L. C.I with CVP (-0.64 (95% CI -0.87, -0.20). CONCLUSION: C.I measured at S.C location is a reliable measure to assess hydration status in spontaneously breathing children, while IVC/aortic ratio performs well for patients on positive pressure. C.I measured at R.L. region has a strong negative correlation with CVP.

Meta Tag

Content Type Presentation

Knowledge Area Pediatrics

Knowledge Area Procedures

Knowledge Area Cardiovascular

Knowledge Level Advanced

Membership Level Select

Tag Pediatrics

Tag Ultrasound

Tag Hemodynamic Monitoring

Tag Point of Care

Tag Cardiothoracic Critical Care

Year 2022

Keywords

Tara Osman

advanced practice registered nurse

point-of-care ultrasound

intravascular fluid volume

hydration assessment

	Society of Critical Care Medicine 500 Midway Drive Mount Prospect, IL 60056 USA Phone: +1 847 827-6888 Fax: +1 847 439-7226 Email: support@sccm.org	Contact Us About SCCM Newsroom Advertising & Sponsorship DONATE	MySCCM LearnICU Patients & Families Surviving Sepsis Campaign Critical Care Societies Collaborative	GET OUR NEWSLETTER
© Society of Critical Care Medicine. All rights reserved. \| Privacy Statement \| Terms & Conditions The Society of Critical Care Medicine, SCCM, and Critical Care Congress are registered trademarks of the Society of Critical Care Medicine.