Fluid Balance and Body Weight Changes in Critically Ill Adult Patients

Study Overview
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Brief Summary
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Positive fluid status has been consistently associated with worse prognosis in critically ill adult patients.However, observational studies showed poor agreement between fluid balance and body weight changes. The objective of the study is to compare the measurements of FB and BW over time and to assess correlation with ICU mortality.

Detailed Description
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Positive fluid status has been consistently associated with worse prognosis in critically ill adult patients. Daily and cumulative fluid balance (FB) is a routine nursing activity in intensive care unit (ICU). In view of the potential for errors in the calculation of FB totals and the problem of accounting for insensible fluid losses, measurement of body weight (BW) changes is an alternative non-invasive method commonly used for estimating body fluid status. Its accuracy over FB assumes a one kilogram change in BW equates to a one liter gain or loss in body fluid volume. However, observational studies showed poor agreement between those measurements, particularly among individuals staying more than a week in ICU possibly due to muscle and fat loss as well as bone demineralization. The objective of the study is to compare the measurements of FB and BW over time and to assess correlation with ICU mortality.

Official Title
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Fluid Balance and Body Weight Changes in Critically Ill Adult Patients

Conditions
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Critical Illness, Fluid Overload

Intervention / Treatment
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* Other: Regular critical care


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals aged >18 years-old admitted to ICU; Expected length of ICU stay superior to 24 hours. Exclusion Criteria: Individuals receiving oral diet; Actual body weight superior to 227kgs or 501lb.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Included individuals<br>Adult patients consecutively admitted to the ICU from June to October 2018 are eligible if expected length of stay is superior to 24 hours and no oral nutritional has been offered. | Other: Regular critical care<br>* Clinical demographic data, daily and cumulative FB (input minus output) with and without insensible fluid losses, and daily and total BW changes are recorded, as well as survival outcome.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between daily fluid balance (difference between fluid input and output during 24 hours) and the change on daily weight | Correlation between daily fluid balance and weight change (Bland-Altman agreement test) | At midnight every 24 hours up to patient's ICU discharge or up to 6 months, whichever comes first. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between cumulative fluid balance and total weight change | Correlation between cumulative fluid balance and total weight change (Bland-Altman) | Last day of each patient's ICU hospitalization, up to 6 months | 
| Discriminative power of fluid balance in predicting ICU mortality | Area under ROC curve for fluid balance (L). ICU mortality as reference variable. | Through study completion, up to 6 months | 
| Discriminative power of body weight changes in predicting ICU mortality | Area under ROC curve for body weight change (kg). ICU mortality as reference variable. | Through study completion, up to 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fluid Balance, Body Weight Change, Critical Illness