Carotid Doppler Ultrasound for the Measurement of Intravascular Volume Status

Sepsis Clinical Trial

Official title:

Carotid Doppler Ultrasound for the Measurement of Intravascular Volume Status During Lower Body Negative Pressure Simulation

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02907931
• Other study ID #: 1608018234
• Status: Completed
• Phase: N/A
• Start date: September 2016
• Est. completion date: January 2020

Study information

• Verified date: January 2020
• Source: Yale University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Ultrasound represents an attractive non-invasive method to assess hemodynamic status. Understanding dynamic changes in hemodynamics in situations such as hypovolemia, sepsis, and cardiogenic shock can potentially help improve patient care. However, the inter-rater reliability and accuracy of how various ultrasound measurements reflect dynamic changes in physiology remains incompletely understood. Overall our aims are to investigate the use of ultrasound in a controlled setting, specifically using lower body negative pressure (LBNP), which can simulate hypovolemia at varied levels in human volunteers.

Aim 1: To determine the change in carotid blood flow (measured by velocity time integral, VTI) in subjects undergoing simulated hypovolemia at LBNP levels that precede vital sign changes.

Hypothesis: Carotid VTI will demonstrate significant changes that precede vital sign changes in simulated hypovolemia.

Aim 2: To compare transcranial color Doppler indices of cerebral blood flow with carotid blood flow, as assessed by VTI of the common carotid artery.

Hypothesis: Changes in transcranial color Doppler indices of cerebral blood flow will be mirrored by changes in carotid blood flow, indicating carotid VTI is an adequate surrogate for measuring cerebral blood flow in variable states of central hypovolemia. However, if cerebral blood flow remains more constant than carotid blood flow throughout varying levels of hypovolemia, our assumption is that cerebral autoregulation alters the relationship between carotid and cerebral blood flow. The more complex procedure of Transcranial Doppler ultrasound (TCD) must be performed to obtain valid assessments of cerebral blood flow.

Description:

Study Design: This is a prospective laboratory study using human volunteers.

Study Setting and Subjects: The study will take place in The John B. Pierce Laboratory where volunteers will be subjected to lower body negative pressure using the on-site LBNP chamber.

Protocol: Study subjects will be instructed to refrain from caffeine, alcohol, or cigarettes within 12 hours of the protocol, but will otherwise be allowed their routine oral intake prior to enrollment. The chamber is constructed of a sealed wood and acrylic box that is connected to a vacuum. Subjects will be placed into the chamber, which is sealed to the level of their pelvis by a neoprene skirt. Chamber pressure is transduced to an electronic digital manometer. The pressure in the chamber will reduced rapidly and held for 15-minute intervals at -5, -10, -15, and -20 mm Hg. If the subject becomes lightheaded, nauseated, or does not tolerate the test run in any way; negative pressure will be stopped.

Subjects will be monitored with continuous electrocardiogram monitoring, a standard automated blood pressure cuff, and a noninvasive beat-to-beat hemodynamic monitor (Finometer, Finapres Medical Systems, Amsterdam, The Netherlands). All carotid ultrasound measurements will be performed by specifically trained emergency physicians, using a Philips ultrasound machine (Philips Medical Systems, Andover, MA) equipped with phased and linear array probes programmed with Doppler capability. For transcranial Doppler imaging, we will use a 5- to 1-MHz sector array transducer and an Iu-22 ultrasound system (Philips Healthcare, Best, the Netherlands). Duplex sonography will be performed at the lower end of the frequency range (1-2 MHz) for better sound wave penetration of selected bone windows. For both the common carotid artery and transcranial portion of this study, we will obtain spectral Doppler waveform tracings and record measurements of corresponding vessel diameters. We will use data generated from software analysis of these spectral tracings to calculate hemodynamic parameters of interest to our study. Calculations are based on Bernoulli's principles of fluid dynamics.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 29
• Est. completion date: January 2020
• Est. primary completion date: July 2018
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 60 Years

Eligibility

Inclusion criteria:

1. Generally healthy

2. Able to provide informed consent

3. Over 18 years of age

Exclusion criteria:

1. Non-English speaking or decisionaly impaired

2. Significant medical illness (as determined by the study physician, JC)

3. Taking vasoactive medications

4. Older than 60 years of age

5. Inability to lie flat for prolonged period

6. Severe claustrophobia

7. Pregnant

Related Conditions & MeSH terms

• Hypotension
• Sepsis

Intervention

Other:
• Point of Care Ultrasound

Locations

Country	Name	City	State
United States	John B. Pierce Laboratory	New Haven	Connecticut

Sponsors (1)

Lead Sponsor	Collaborator
Yale University

Country where clinical trial is conducted

United States, 

References & Publications (18)

Bathala L, Mehndiratta MM, Sharma VK. Transcranial doppler: Technique and common findings (Part 1). Ann Indian Acad Neurol. 2013 Apr;16(2):174-9. doi: 10.4103/0972-2327.112460. — View Citation

Blehar DJ, Glazier S, Gaspari RJ. Correlation of corrected flow time in the carotid artery with changes in intravascular volume status. J Crit Care. 2014 Aug;29(4):486-8. doi: 10.1016/j.jcrc.2014.03.025. Epub 2014 Apr 2. — View Citation

Cooke WH, Ryan KL, Convertino VA. Lower body negative pressure as a model to study progression to acute hemorrhagic shock in humans. J Appl Physiol (1985). 2004 Apr;96(4):1249-61. Review. — View Citation

Dellinger RP, Levy MM, Rhodes A, Annane D, Gerlach H, Opal SM, Sevransky JE, Sprung CL, Douglas IS, Jaeschke R, Osborn TM, Nunnally ME, Townsend SR, Reinhart K, Kleinpell RM, Angus DC, Deutschman CS, Machado FR, Rubenfeld GD, Webb S, Beale RJ, Vincent JL, Moreno R; Surviving Sepsis Campaign Guidelines Committee including The Pediatric Subgroup. Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012. Intensive Care Med. 2013 Feb;39(2):165-228. doi: 10.1007/s00134-012-2769-8. Epub 2013 Jan 30. — View Citation

Lamia B, Ochagavia A, Monnet X, Chemla D, Richard C, Teboul JL. Echocardiographic prediction of volume responsiveness in critically ill patients with spontaneously breathing activity. Intensive Care Med. 2007 Jul;33(7):1125-1132. doi: 10.1007/s00134-007-0646-7. Epub 2007 May 17. — View Citation

Levitov A, Marik PE. Echocardiographic assessment of preload responsiveness in critically ill patients. Cardiol Res Pract. 2012;2012:819696. doi: 10.1155/2012/819696. Epub 2011 Sep 12. — View Citation

Mackenzie DC, Khan NA, Blehar D, Glazier S, Chang Y, Stowell CP, Noble VE, Liteplo AS. Carotid Flow Time Changes With Volume Status in Acute Blood Loss. Ann Emerg Med. 2015 Sep;66(3):277-282.e1. doi: 10.1016/j.annemergmed.2015.04.014. Epub 2015 May 21. — View Citation

Mackenzie DC, Noble VE. Assessing volume status and fluid responsiveness in the emergency department. Clin Exp Emerg Med. 2014 Dec 31;1(2):67-77. eCollection 2014 Dec. Review. — View Citation

Maizel J, Airapetian N, Lorne E, Tribouilloy C, Massy Z, Slama M. Diagnosis of central hypovolemia by using passive leg raising. Intensive Care Med. 2007 Jul;33(7):1133-1138. doi: 10.1007/s00134-007-0642-y. Epub 2007 May 17. — View Citation

Marik PE, Cavallazzi R, Vasu T, Hirani A. Dynamic changes in arterial waveform derived variables and fluid responsiveness in mechanically ventilated patients: a systematic review of the literature. Crit Care Med. 2009 Sep;37(9):2642-7. doi: 10.1097/CCM.0b013e3181a590da. Review. — View Citation

Marik PE, Levitov A, Young A, Andrews L. The use of bioreactance and carotid Doppler to determine volume responsiveness and blood flow redistribution following passive leg raising in hemodynamically unstable patients. Chest. 2013 Feb 1;143(2):364-370. doi: 10.1378/chest.12-1274. — View Citation

Marik PE. Iatrogenic salt water drowning and the hazards of a high central venous pressure. Ann Intensive Care. 2014 Jun 21;4:21. doi: 10.1186/s13613-014-0021-0. eCollection 2014. Review. — View Citation

Moore CL, Rose GA, Tayal VS, Sullivan DM, Arrowood JA, Kline JA. Determination of left ventricular function by emergency physician echocardiography of hypotensive patients. Acad Emerg Med. 2002 Mar;9(3):186-93. Erratum in: Acad Emerg Med 2002 Jun;9(6):642. — View Citation

Moore CL, Tham ET, Samuels KJ, McNamara RL, Galante NJ, Stachenfeld N, Shelley K, Dziura J, Silverman DG. Tissue Doppler of early mitral filling correlates with simulated volume loss in healthy subjects. Acad Emerg Med. 2010 Nov;17(11):1162-8. doi: 10.1111/j.1553-2712.2010.00906.x. — View Citation

Rivers E, Nguyen B, Havstad S, Ressler J, Muzzin A, Knoblich B, Peterson E, Tomlanovich M; Early Goal-Directed Therapy Collaborative Group. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med. 2001 Nov 8;345(19):1368-77. — View Citation

Stevens PM, Lamb LE. Effects of lower body negative pressure on the cardiovascular system. Am J Cardiol. 1965 Oct;16(4):506-15. — View Citation

Stolz LA, Mosier JM, Gross AM, Douglas MJ, Blaivas M, Adhikari S. Can emergency physicians perform common carotid Doppler flow measurements to assess volume responsiveness? West J Emerg Med. 2015 Mar;16(2):255-9. doi: 10.5811/westjem.2015.1.24301. Epub 2015 Feb 26. — View Citation

Thomas KN, Lewis NC, Hill BG, Ainslie PN. Technical recommendations for the use of carotid duplex ultrasound for the assessment of extracranial blood flow. Am J Physiol Regul Integr Comp Physiol. 2015 Oct;309(7):R707-20. doi: 10.1152/ajpregu.00211.2015. Epub 2015 Jul 8. Review. — View Citation

* Note: There are 18 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	changes in carotid blood flow (measured by velocity time integral, VTI) in subjects undergoing simulated hypovolemia	We will attach adhesive electrodes to your chest which allow us to monitor and record your vital signs. You will lie on your back on a table with the lower half of your body enclosed in a box. The box has a vacuum that creates suction and causes blood to pool in your legs and feet. Next you will do a Lower Body Negative Pressure test. For this test, you will lie with your lower body in the box while we apply increasing levels of suction, over 4 different intervals, lasting 2 minutes each. We will repeat the suction for longer times at each interval and obtain ultrasound images of blood vessels in your head and neck. Each interval may last up to 20 minutes for a total of up to 80 minutes time spent in the chamber.	over the course of 1-2 hours during which subjects will undergo incremental changes in lower body negative pressure