Ultrasound Assessment of Volume in Patients on Continuous Dialysis
Condition: Volume Overload; Kidney Failure; Respiratory Failure
MeSH terms: Respiratory Insufficiency; Renal Insufficiency
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Share ultrasound measurement of IVC collapsibility to Nephrology Attending; Do not share ultrasound measurement of IVC collapsibility to Nephrology Attending
Intervention type(s): Other; Other
Intervention description(s): Nephrology attending will be provided with the respiratory variability of IVC diameter as a percent, in addition to a predefined cutoff for responsiveness to volume resuscitation of < 12%. The information will be provided before rounds and before the attending sets the fluid removal goals on dialysis for that day.; Respiratory variability of IVC diameter will be measured, but the measurement result will not be shared with the treating team.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Supportive Care