Velocity-Time Integral: A Bedside Echocardiography Technique Finding a Place in the Emergency Department



      Point-of-care ultrasound is a fundamental tool in the emergency department when managing the critically ill patient. Determining a patient's hemodynamic status at the bedside can better guide resuscitation efforts. The left ventricular outflow tract velocity–time integral (VTI) is a validated, noninvasive, and rapidly acquired echocardiographic measurement that is analogous to stroke volume.


      VTI can be used to determine fluid responsiveness and to risk stratify patients, particularly in pulmonary embolism, heart failure, and sepsis. Emergency physicians with limited experience can successfully measure VTI in a timely and accurate manner. However, VTI measurement is not commonly taught in emergency medicine residency and, as a result, it is an underused tool.


      VTI is an objective tool for clinicians to assess the hemodynamic status of critically ill patients. Understanding the acquisition of VTI and proper application in the context of the patient's history, clinical examination, and other bedside ultrasound findings, should be reviewed within the emergency medicine residency ultrasound curriculum. This article provides a simple four-step protocol, as well as bedside applications and potential limitations for VTI in the ED.


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      1. Ultrasound guidelines: emergency, point of care, and clinical ultrasound guidelines in medicine.
        Ann Emerg Med. 2017; 69: e27-e54
        • Mowat DH
        • Haites NE
        • Rawles JM.
        Aortic blood velocity measurement in healthy adults using a simple ultrasound technique.
        Cardiovasc Res. 1983; 17: 75-80
        • Goldman JH
        • Schiller NB
        • Lim DC
        • Redberg RF
        • Foster E.
        Usefulness of stroke distance by echocardiography as a surrogate marker of cardiac output that is independent of gender and size in a normal population.
        Am J Cardiol. 2001; 87: 499-502
        • Porter TR
        • Shillcutt SK
        • Adams MS
        • et al.
        Guidelines for the use of echocardiography as a monitor for therapeutic intervention in adults: a report from the American Society of Echocardiography.
        J Am Soc Echocardiogr. 2015; 28: 40-56
        • Tchorz KM
        • Chandra MS
        • Markert RJ
        • et al.
        Comparison of hemodynamic measurements from invasive and noninvasive monitoring during early resuscitation.
        J Trauma Acute Care Surg. 2012; 72: 852-860
        • Cecconi M
        • De Backer D
        • Antonelli M
        • et al.
        Consensus on circulatory shock and hemodynamic monitoring. Task Force of the European Society of Intensive Care Medicine.
        Intensive Care Med. 2014; 40: 1795-1815
        • Malbrain MLNG
        • De Tavernier B
        • Haverals S
        • et al.
        Executive summary on the use of ultrasound in the critically ill: consensus report from the 3rd Course on Acute Care Ultrasound (CACU).
        Anaesthesiol Intensive Ther. 2017; 49: 393-411
        • Mercado P
        • Maizel J
        • Beyls C
        • et al.
        Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient.
        Crit Care. 2017; 21: 136
        • Villavicencio C
        • Leache J
        • Marin J
        • et al.
        Basic critical care echocardiography training of intensivists allows reproducible and reliable measurements of cardiac output.
        Ultrasound J. 2019; 11: 5
        • Zhang Y
        • Wang Y
        • Shi J
        • Hua Z
        • Xu J.
        Cardiac output measurements via echocardiography versus thermodilution: a systematic review and meta-analysis.
        PLoS One. 2019; 14e0222105
        • Blanco P.
        Rationale for using the velocity-time integral and the minute distance for assessing the stroke volume and cardiac output in point-of-care settings.
        Ultrasound J. 2020; 12: 21
        • Betcher J
        • Majkrzak A
        • Cranford J
        • et al.
        Feasibility study of advanced focused cardiac measurements within the emergency department.
        Crit Ultrasound J. 2018; 10: 10
        • Porter TR
        • Shillcutt SK
        • Adams MS
        • et al.
        Guidelines for the Use of Echocardiography as a Monitor for Therapeutic Intervention in Adults: A Report from the American Society of Echocardiography.
        J Indian Acad Echocardiogr Cardiovasc Imaging. 2020; 4: 122-136
        • McGregor D
        • Sharma S
        • Gupta S
        • Ahmad S
        • Godec T
        • Harris T.
        Emergency department non-invasive cardiac output study (EDNICO): a feasibility and repeatability study.
        Scand J Trauma Resusc Emerg Med. 2019; 27: 30
        • Am Dinh V
        • Ko HS
        • Rao R
        • et al.
        Measuring cardiac index with a focused cardiac ultrasound examination in the ED.
        Am J Emerg Med. 2012; 30: 1845-1851
        • Dittmann H
        • Voelker W
        • Karsch KR
        • Seipel L.
        Influence of sampling site and flow area on cardiac output measurements by Doppler echocardiography.
        J Am Coll Cardiol. 1987; 10: 818-823
        • Mitchell C
        • Rahko PS
        • Blauwet LA
        • et al.
        Guidelines for performing a comprehensive transthoracic echocardiographic examination in adults: recommendations from the American Society of Echocardiography.
        J Am Soc Echocardiogr. 2019; 32: 1-64
        • Quiñones MA
        • Otto CM
        • Stoddard M
        • Waggoner A
        • Zoghbi WA
        Doppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography Recommendations for quantification of Doppler echocardiography: a report from the Doppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography.
        J Am Soc Echocardiogr. 2002; 15: 167-184
        • Blanco P
        • Aguiar FM
        • Blaivas M.
        Rapid ultrasound in shock (RUSH) velocity-time integral: a proposal to expand the RUSH protocol.
        J Ultrasound Med. 2015; 34: 1691-1700
        • Mitchell D
        • Leng S
        • Gardiner S
        • Jones S
        • Thompson D.
        Using point-of-care bedside ultrasound for volume assessment in early shock: an outcome study.
        Chest. 2016; 149: A148
        • Cherpanath TG
        • Hirsch A
        • Geerts BF
        • et al.
        Predicting fluid responsiveness by passive leg raising: a systematic review and meta-analysis of 23 clinical trials.
        Crit Care Med. 2016; 44: 981-991
        • Monnet X
        • Marik P
        • Teboul JL.
        Passive leg raising for predicting fluid responsiveness: a systematic review and meta-analysis.
        Intensive Care Med. 2016; 42: 1935-1947
        • Ansari BM
        • Zochios V
        • Falter F
        • Klein AA.
        Physiological controversies and methods used to determine fluid responsiveness: a qualitative systematic review.
        Anaesthesia. 2016; 71: 94-105
        • Stetz CW
        • Miller RG
        • Kelly GE
        • Raffin TA.
        Reliability of the thermodilution method in the determination of cardiac output in clinical practice.
        Am Rev Respir Dis. 1982; 126: 1001-1004
        • Douglas IS
        • Alapat PM
        • Corl KA
        • et al.
        Fluid response evaluation in sepsis hypotension and shock: a randomized clinical trial.
        Chest. 2020; 158: 1431-1445
        • Yuriditsky E
        • Mitchell OJI
        • Sibley RA
        • et al.
        Low left ventricular outflow tract velocity time integral is associated with poor outcomes in acute pulmonary embolism.
        Vasc Med. 2020; 25: 133-140
        • Tan C
        • Rubenson D
        • Srivastava A
        • et al.
        Left ventricular outflow tract velocity time integral outperforms ejection fraction and Doppler-derived cardiac output for predicting outcomes in a select advanced heart failure cohort.
        Cardiovasc Ultrasound. 2017; 15: 18
        • Omote K
        • Nagai T
        • Iwano H
        • et al.
        Left ventricular outflow tract velocity time integral in hospitalized heart failure with preserved ejection fraction.
        ESC Heart Fail. 2020; 7: 167-175
        • Prosperi-Porta G
        • Solverson K
        • Fine N
        • Humphreys CJ
        • Ferland A
        • Weatherald J.
        Echocardiography-derived stroke volume index is associated with adverse in-hospital outcomes in intermediate-risk acute pulmonary embolism: a retrospective cohort study.
        Chest. 2020; 158: 1132-1142
        • Ristow B
        • Na B
        • Ali S
        • Whooley MA
        • Schiller NB.
        Left ventricular outflow tract and pulmonary artery stroke distances independently predict heart failure hospitalization and mortality: the Heart and Soul Study.
        J Am Soc Echocardiogr. 2011; 24: 565-572