Effect of insonation angle on peak systolic velocity variation

Radparvar, Joshua R; Lim, George; Chiem, Alan

doi:10.1016/j.ajem.2019.01.050

Cited by 10 publications

(5 citation statements)

References 17 publications

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“…A 2019 study by Radparvar et al, highlights the importance of the angle of insonation when measuring carotid DVpeak. 26 They demonstrated that a more oblique probe position on a participant's neck produced more precise results. Specifically, as the angle of insonation was increased from 46 to 90 the standard error of the carotid DVpeak increased from 6% to 14%.…”

Section: Discussionmentioning

confidence: 99%

Respiratory Variation in Carotid Artery Peak Systolic Velocity Is Unable to Predict Fluid Responsiveness in Spontaneously Breathing Critically Ill Patients When Assessed by Novice Physician Sonologists

Abbasi

Nayeemuddin

Azab

et al. 2020

J Intensive Care Med

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Background: Respiratory variation in carotid artery peak systolic velocity (ΔVpeak) assessed by point-of-care ultrasound (POCUS) has been proposed as a noninvasive means to predict fluid responsiveness. We aimed to evaluate the ability of carotid ΔVpeak as assessed by novice physician sonologists to predict fluid responsiveness. Methods: This study was conducted in 2 intensive care units. Spontaneously breathing, nonintubated patients with signs of volume depletion were included. Patients with atrial fibrillation/flutter, cardiogenic, obstructive or neurogenic shock, or those for whom further intravenous (IV) fluid administration would be harmful were excluded. Three novice physician sonologists were trained in POCUS assessment of carotid ΔVpeak. They assessed the carotid ΔVpeak in study participants prior to the administration of a 500 mL IV fluid bolus. Fluid responsiveness was defined as a ≥10% increase in cardiac index as measured using bioreactance. Results: Eighty-six participants were enrolled, 50 (58.1%) were fluid responders. Carotid ΔVpeak performed poorly at predicting fluid responsiveness. Test characteristics for the optimum carotid ΔVpeak of 8.0% were: area under the receiver operating curve = 0.61 (95% CI: 0.48-0.73), sensitivity = 72.0% (95% CI: 58.3-82.56), specificity = 50.0% (95% CI: 34.5-65.5). Conclusions: Novice physician sonologists using POCUS are unable to predict fluid responsiveness using carotid ΔVpeak. Until further research identifies key limiting factors, clinicians should use caution directing IV fluid resuscitation using carotid ΔVpeak.

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Section: Discussionmentioning

confidence: 99%

Respiratory Variation in Carotid Artery Peak Systolic Velocity Is Unable to Predict Fluid Responsiveness in Spontaneously Breathing Critically Ill Patients When Assessed by Novice Physician Sonologists

Abbasi

Nayeemuddin

Azab

et al. 2020

J Intensive Care Med

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“…As a result, both manual and automatic cardiac output measurements had poor accuracy compared to the standardized control. Measurement variation likely has multiple sources, including human factors [ 16 , 17 ], ultrasound factors [ 18 ], and intrinsic fluctuation secondary to patient physiology (e.g., respiratory variation). However, ultrasound and patient factors were less likely to contribute to measurement variability in our study since trainees and expert echocardiographers used the same machines and obtained measurements from only one patient.…”

Section: Discussionmentioning

confidence: 99%

Measuring the accuracy of cardiac output using POCUS: the introduction of artificial intelligence into routine care

et al. 2022

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Background Shock management requires quick and reliable means to monitor the hemodynamic effects of fluid resuscitation. Point-of-care ultrasound (POCUS) is a relatively quick and non-invasive imaging technique capable of capturing cardiac output (CO) variations in acute settings. However, POCUS is plagued by variable operator skill and interpretation. Artificial intelligence may assist healthcare professionals obtain more objective and precise measurements during ultrasound imaging, thus increasing usability among users with varying experience. In this feasibility study, we compared the performance of novice POCUS users in measuring CO with manual techniques to a novel automation-assisted technique that provides real-time feedback to correct image acquisition for optimal aortic outflow velocity measurement. Methods 28 junior critical care trainees with limited experience in POCUS performed manual and automation-assisted CO measurements on a single healthy volunteer. CO measurements were obtained using left ventricular outflow tract (LVOT) velocity time integral (VTI) and LVOT diameter. Measurements obtained by study subjects were compared to those taken by board-certified echocardiographers. Comparative analyses were performed using Spearman’s rank correlation and Bland–Altman matched-pairs analysis. Results Adequate image acquisition was 100% feasible. The correlation between manual and automated VTI values was not significant (p = 0.11) and means from both groups underestimated the mean values obtained by board-certified echocardiographers. Automated measurements of VTI in the trainee cohort were found to have more reproducibility, narrower measurement range (6.2 vs. 10.3 cm), and reduced standard deviation (1.98 vs. 2.33 cm) compared to manual measurements. The coefficient of variation across raters was 11.5%, 13.6% and 15.4% for board-certified echocardiographers, automated, and manual VTI tracing, respectively. Conclusions Our study demonstrates that novel automation-assisted VTI is feasible and can decrease variability while increasing precision in CO measurement. These results support the use of artificial intelligence-augmented image acquisition in routine critical care ultrasound and may have a role for evaluating the response of CO to hemodynamic interventions. Further investigations into artificial intelligence-assisted ultrasound systems in clinical settings are warranted.

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“…Future algorithms could guide the sonographer towards correct placing and setting of the US probe, improving reliability and repeatability of measurements. Furthermore, the development of wearable devices will likely mitigate the effect of insonation angle (Radparvar et al 2020), minimize positioning errors and allow continuous measurement. Lui et al (Lui et al 2005) found no significant difference between manual velocity measurements and those obtained with an automatic peak velocity tracker.…”

Section: Automating Cdumentioning

confidence: 99%

Carotid Doppler ultrasound for non-invasive haemodynamic monitoring: a narrative review

et al. 2022

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Accurate haemodynamic monitoring is the cornerstone in the management of critically ill patients. It guides the optimization of tissue and organ perfusion in order to prevent multiple organ failure. In the past decades, carotid Doppler ultrasound (CDU) has been explored as a non-invasive alternative for long-established invasive haemodynamic monitoring techniques. Considering the large heterogeneity in reported studies, we conducted a review of the literature to clarify the current status of CDU as a haemodynamic monitoring tool. In this article, firstly an overview is given of the equipment and workflow required to perform a CDU exam in clinical practice, the limitations and technical challenges potentially faced by the CDU sonographer, and the cerebrovascular mechanisms that may influence CDU measurement outcomes. The following chapter describes alternative techniques for non-invasive haemodynamic monitoring, detailing advantages and limitations compared to CDU. Next, a comprehensive review of the literature regarding the use of CDU for haemodynamic monitoring is presented. Based on the outcomes of these studies, we assess the applicability of CDU-derived parameters within three clinical domains (cardiac output, volume status, and fluid responsiveness), and amongst different patient groups. Furthermore, feasibility aspects, training requirements and technical developments of CDU are addressed. Finally, recommendations are provided to improve the quality and standardization of future research and clinical practice in this field. Although CDU is not yet interchangeable with invasive “gold standard” cardiac output monitoring, the present work shows that certain CDU-derived parameters prove promising in the context of functional haemodynamic monitoring.

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Effect of insonation angle on peak systolic velocity variation

Cited by 10 publications

References 17 publications

Respiratory Variation in Carotid Artery Peak Systolic Velocity Is Unable to Predict Fluid Responsiveness in Spontaneously Breathing Critically Ill Patients When Assessed by Novice Physician Sonologists

Respiratory Variation in Carotid Artery Peak Systolic Velocity Is Unable to Predict Fluid Responsiveness in Spontaneously Breathing Critically Ill Patients When Assessed by Novice Physician Sonologists

Measuring the accuracy of cardiac output using POCUS: the introduction of artificial intelligence into routine care

Carotid Doppler ultrasound for non-invasive haemodynamic monitoring: a narrative review

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