Ultrasound Measurement of Reactive Hyperemia in Critical Care

The investigators hypothesize that doctors and nurses can undergo a brief period of training and then use ultrasound to accurately measure blood flow in a forearm artery after a brief period when this flow is interrupted with a blood pressure cuff, a measurement the investigators call reactive hyperemia. Reactive hyperemia indicates whether the small blood vessels in the body are healthy -- lower reactive hyperemia indicates worse small blood vessel function. When measured by experienced ultrasound experts, low reactive hyperemia strongly predicts death in critically ill patients with infection (severe sepsis).

The investigators are conducting this study to determine if doctors and nurses, without specific pre-existing expertise in ultrasound, can be trained to make these measurements accurately. If so, the investigators will prove that these measurements can be applied reliably in real-world practice.

The investigators also hypothesize that reactive hyperemia predict the outcomes of illness not just in patients with severe infection, but in other critically ill patients as well.

Finally, the investigators hypothesize that reduced blood flow after blood pressure cuff occlusion is linked with other abnormalities of blood, previously identified in critically ill patients. For example, red blood cells from patients with severe sepsis have been shown to be stiffer than normal, so they are less able to flow along the small blood vessel passages of the body. Red blood cells become stiffer when there is a certain type of stress in the body known as "oxidative stress."

If the investigators show that low reactive hyperemia, stiff red blood cells, and oxidative stress are linked, the investigators hope to develop new treatments that reduce oxidative stress, reduce the stiffness of red blood cells, and in turn improve reactive hyperemia. Improvements in reactive hyperemia indicate improvements in small blood vessel function. Better small blood vessel function means better delivery of oxygen throughout the body. The investigators believe that this will improve outcomes for critically ill patients.

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Key information

Conditions

Severe Sepsis Critical Illness Disease Attributes Infections Inflammation Pathologic Processes Pathological Conditions, Signs and Symptoms Sepsis Systemic Inflammatory Response Syndrome

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Rochester Medical Center

Rochester, New York, 14642, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Patients admitted to University of Rochester Medical Center ICU services with 2 of the 4 systemic inflammatory response syndrome (SIRS) criteria and acute organ dysfunction will be considered for enrollment.
Healthy control subjects >= 18 years of age will be recruited from the University and Rochester region at large.

Exclusion criteria

Critically ill patients:

Refusal of patient or designated surrogate decision-maker to provide written informed consent, or inability to obtain consent within 48 hours of diagnosis
Attending physician refusal
Hematocrit (Hct) < 21%
Acute bleeding requiring PRBC transfusion
History of chronic, dialysis dependent renal failure
End-stage liver disease and Child-Pugh Grade C
History of organ, bone marrow, or stem cell transplant
Pregnancy
Cardiac surgery (including ventricular assist device prior to first sample collection)
Do not resuscitate at screening or plans for withdrawal of life support imminent
Suicide attempt or intentional drug overdose;
Jehovah's witness
Healthy Control subjects:

Absent doppler signal in brachial or radial arteries.
Asymmetric cyanosis, poor capillary refill or cold temperature
Known venous thrombosis or there is asymmetric swelling (arm circumference > 2 inches larger than opposite side).
Evidence of inflammation or impaired skin integrity of the involved limb.
History of surgery involving the blood or lymphatic vessels of this limb, including axillary lymph node dissection, will preclude this testing.
History of Anemia or G6PD deficiency

Treatment and study plan

Primary outcomes

hospital mortality

Time frame: vital status at hospital discharge, an expected average of 3 weeks

Sponsors and collaborators

Lead sponsor

University of Rochester

Other

Registry information

Official study title

Ultrasound Measurement of Reactive Hyperemia in Critical Care: Prognostic and Pathophysiologic Significance

Acronym: URHC

Important dates

Study start: 2013
Primary completion: 2019
Study completion: 2019
First posted: Nov 15, 2012
Registry last updated: Feb 12, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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