Ultrasound Assessment of Volume in Patients on Continuous Dialysis
Ultrasound Assessment of Volume in Patients on Continuous Dialysis
Renal failure and resuscitation measures in critically ill patients can result in fluid
 overload. Fluid overload in renal failure patients can cause harmful effects like pulmonary
 edema, anasarca and congestive cardiac failure exacerbations among other complications. These
 have been associated with increased time on the ventilator, increased length of stay in the
 ICU, and higher overall mortality for patients requiring dialysis in the ICU.

 The current standard of care for adjusting fluid removal rates in patients on continuous
 renal replacement therapy relies on clinical judgement. Clinicians take into account factors
 like the patient's condition, vasopressor requirements, kidney function, total intake and
 outputs, vital signs, and physical examination findings when making daily changes to fluid
 removal rates on dialysis machines. Such assessment is highly subjective and can be
 imprecise/inaccurate leading to hypotension and hemodynamic instability in a critically ill
 patient.

 Use of conventional ultrasound by physicians to assess volume status using compressibility of
 the inferior vena cava has been shown to be a reliable predictor of volume status and can
 help guide therapy. Such use makes bedside volume assessment a non-invasive, rapid,
 repeatable point of care tool that can provide objective data to guide fluid removal
 determine velocity of fluid removal and help identify patients at risk of hypotension and
 hemodynamic instability during the process of fluid removal. Apart from rare possible local
 allergic reactions to ultrasound jelly and transient local discomfort, the disadvantages are
 minimal. Ultrasonography has been considered a safe imaging modality. This protocol will
 measure inferior vena cava compressibility using the General Electric VScan with Dual Probe,
 which has FDA approval for abdominal and vascular imaging in humans.
The study consists of gathering patient data from the chart and performing ultrasound
 measurements of inferior vena cava compressibility at the start of continuous renal
 replacement therapy (CRRT) in patients on the mechanical ventilator in the ICU. Ultrasound
 measurements on the abdomen, as well as recording of clinical data like intake/output,
 weight, pulse pressure variability, vasopressor requirement, nutrition requirement,
 ventilator settings, CRRT settings, and certain laboratory data will be performed at the
 start of the study and then daily for the next 3 days. On the 3rd day, 50 mL of dialysis
 waste fluid will be collected and stored for future analysis.

 At the start of the study, participants will be randomized to two groups. Study activities
 are identical between the two groups and both groups receive ultrasound measurements on the
 abdomen. However, in one group the attending nephrologist on the Acute Consult service will
 be provided with inferior vena cava compressibility measurement information each day before
 the start of rounds. Randomization will follow a predefined schedule, known only to the
 research coordinator, Laura Latta. At no time will the attending physicians receive the
 ultrasound measurements for the group randomized to not have their data shared.

 In addition, the resident, fellow, and attending on the Acute Consult service will be asked
 to assess the volume status of each participant at the start of the study and then daily for
 next 3 days. The volume assessment will consist of answering the following question, "Would
 you recommend fluid removal in this patient today (Yes/No/Unsure)?" The question will be
 asked verbally by Dr. Narasimha Krishna. Each individual's level of training (post-graduation
 year) and the response will be recorded. Individual names will not be recorded and responses
 will not be shared with the attending. Responses to this question are not anticipated to
 affect management of the participant.

 During the follow up phase, the electronic medical records will be checked at day 7 and day
 30 to determine if the participant is still in the intensive care unit, is still on the
 ventilator, or is still alive, or still in the hospital. Both groups will have the same
 follow up time.

 Primary outcome measures include: 1) Time to extubation; 2) Length of ICU stay; 3) Length of
 hospital stay; and 4) 30 day mortality.

 Secondary outcome measures include: 1) Difference in net fluid removal by CRRT at day 3
 between the 2 groups; 2) Agreement between volume assessment and inferior vena cava
 compressibility by level of training.
Inclusion Criteria:

 -  Acute kidney injury requiring initiation of continuous renal replacement therapy

 -  Respiratory failure requiring mechanical ventilation

 Exclusion Criteria:

 -  cirrhosis of liver

 -  pregnant woman

 -  abdominal surgery interfering with placement of ultrasound probe

 -  end-stage kidney disease