Comparison of Non-Invasive Methods of Assessing Fluid Responsiveness in ED and ICU Patients

This is a diagnostic accuracy study comparing selected ultrasound techniques to a well
validated standard for predicting fluid responsiveness in septic patients (NICOM). The
primary outcomes will be reported in sensitivity, specificity, positive predictive value,
negative predictive value, likelihood ratios, and receiver operating characteristic curves.

The timeframe for measurement is within 72 hours of the subjects' admission. Determination
of the outcome (i.e., whether a subject is fluid responsive) is based upon the data
generated by the NICOM device. The NICOM generates data within 5 minutes of assessment. The
ultrasound modalities to be studied will generate data within 5 minutes of assessment as
well. The US data will be compared to the NICOM data to generate the statistics listed in
this protocol. There is no further planned follow-up for the subjects.

1. The investigators will compare the ability of dynamic changes in inferior vena caval
diameter (IVC-CI), dynamic changes in peripheral arterial waveform derived variables
(PA Doppler), and dynamic changes in left ventricular outflow tract waveform derived
variables (LVOT Doppler) to detect fluid responsiveness (FRes) relative to FRes as
assessed by bioreactance cardiac output monitoring before and after passive leg raise
(PLR).

Hypothesis: PA Doppler and LVOT Doppler will have superior sensitivity and specificity
to predict FRes in comparison to IVC-CI.

2. The investigators will evaluate data acquisition duration and data acquisition failure
rate of IVC-CI, PA Doppler, and LVOT Doppler. Hypothesis: PA Doppler will have shorter
data acquisition durations in comparison to LVOT velocity variation and IVC-CI.

Hypothesis: PA Doppler will have lower data acquisition failure rates in comparison to
LVOT velocity variation and IVC-CI.

3. The investigators will compare the ability of IVC-CI, PA Doppler, and LVOT Doppler to
predict FRes in comparison to FRes as predicted by clinical judgment.

Hypothesis: PA Doppler and LVOT Doppler will have superior sensitivity and specificity
to predict FRes in comparison to clinical judgment.

4. The investigators will evaluate the ability of dynamic changes in PA corrected flow
times (cFT) to detect FRes relative to FRes as assessed by bioreactance cardiac output
monitoring before and after PLR. Hypothesis: cFT will have greatest sensitivity and
specificity to predict FRes at a Δflow time threshold of ≥15% after PLR.

Hypothesis: At a Δflow time threshold of ≥15%, cFT will have superior sensitivity and
specificity to detect FRes in comparison to IVC-CI.

Inclusion Criteria:

- Subjects presenting to the ED will be screened in accordance with the Olive View
Medical Center Sepsis Waiver, and subjects meeting two of the following four criteria
will be eligible for inclusion in the study: Temperature >38/100.4 or <36/96.8, heart
rate >90, respiratory rate >20 or PaCO2<32, and WBC >12K or <4K or > 10% bands
(neutrophils). The clinical team will be contacted regarding patients identified
based on this initial screening, and if the patient is determined to have a suspected
infection and a fluid bolus is planned, the patient will be enrolled in the study if
they meet the following criteria:

- Adult between the age of 18 to 90 years old;

- Not pregnant;

- Not using non-invasive positive pressure ventilation (CPAP or BiPAP);

- No history of heart, lung, and/or liver transplant;

- Not determined by the clinical team to be acutely unstable requiring immediate
intervention at the time of data collection, and;

- No contraindications to a passive leg raise test (known or suspected cranio-cerebral
or C-spine injury, venous thrombosis, orthopedic injury requiring immobilization or
traction, or other contraindications as per clinical team).

Exclusion Criteria:

- Pregnant;

- Using non-invasive positive pressure ventilation (CPAP or BiPAP);

- Presence of or suspected elevated intracranial pressure;

- Presence of central venous catheters or other medical devices that prevent the use of
bedside ultrasound;

- History of heart, lung, and/or liver transplant;

- History of critical aortic stenosis or severe aortic insufficiency;

- Determined by the clinical team to be acutely unstable and requiring immediate
intervention at the time of study enrollment or data collection or;

- Has a contraindication to passive leg raise maneuver, e.g. known cervical spinal
injury, deep venous thrombosis, orthopedic injury requiring immobilization or
traction.