Publications by authors named "Maxine LeSaux"

9 Publications

  • Page 1 of 1

A Discreet Wearable IoT Sensor for Continuous Transdermal Alcohol Monitoring - Challenges and Opportunities.

IEEE Sens J 2021 Feb 12;21(4):5322-5330. Epub 2020 Oct 12.

Department of Biomedical Engineering, George Washington University, Washington, DC, 20052 USA.

Non-invasive continuous alcohol (ethanol) monitoring has potential applications in both population research and in clinical management of acute alcohol intoxication or chronic alcoholism. Current wearable monitors based on transdermal alcohol content (TAC) sensing have limited accessibility and blood alcohol content (BAC) quantification accuracy. Here we describe the development of a self-contained discreet wearable transdermal alcohol (TAC) sensor in the form of a wristband or armband. This sensor can detect vapor-phase alcohol in perspiration from 0.09 ppm (equivalent to 0.09 mg/dL sweat alcohol concentration at 25 °C under Henry's Law equilibrium) to over 500 ppm at one-minute time resolution. Additionally, a digital sensor was employed to monitor the temperature and humidity levels inside the sensing chamber. Two male human subjects were recruited to conduct studies with alcohol consumption using calibrated prototype TAC sensors to validate the performance. Our preliminary data demonstrated that, under well-controlled conditions, this sensor can acquire TAC curves at low doses (1-2 standard drinks). Moreover, TAC data for different doses can be easily distinguished. However, substantial interpersonal and intrapersonal variabilities in measurement data were also observed in experiments with less controlled conditions. Our observations suggest that perspiration rate might be an important contributing factor to these variabilities. Further studies with sufficient sample sizes are required to validate and characterize the impact of different perspiration rates on TAC sensors, which may inform more reproducible and accurate sensor designs in the future.
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http://dx.doi.org/10.1109/jsen.2020.3030254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7978232PMC
February 2021

Optic Nerve Sheath Diameter Measured by Point-of-Care Ultrasound and MRI.

J Neuroimaging 2020 11 8;30(6):793-799. Epub 2020 Sep 8.

Department of Radiology, The George Washington University Medical Center, Washington, DC.

Background And Purpose: Ultrasound (US) measurement of the optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) is a method frequently used to screen for an increased intracranial pressure. The aim of this study was to assess the accuracy of US measurements of ONSD and OND, when compared to magnetic resonance imaging (MRI) measurements as the criterion standard.

Methods: In this prospective, single-institution study, orbital US was performed for those patients requiring an emergent brain MRI. ONSD and OND of both eyes were measured in the axial and coronal planes in straight gaze by US. ONSD and OND from brain and orbital MRI were measured by two neuroradiologists. Correlation and agreement between readings were assessed using Pearson's correlations.

Results: Eighty-two patients met inclusion criteria. The mean axial and coronal ONSD in the MRI examinations was 5.6 and 5.7 mm at 3-5.9 mm behind the globe, respectively. The mean ONSD from the US measurements was 6.22 and 5.52 mm in the axial and coronal planes, respectively. The mean OND in US examinations was 4.31 mm (axial) and 3.68 mm (coronal). Axial versus coronal measurements of ONSD had a modest correlation in US assessment with an r of .385 (P < .001) but there were no correlations between any of the US and MRI measurements.

Conclusions: In measuring ONSD and OND, US measurements showed a modest correlation between axial and coronal measurements, but no concordance was found between US and MRI in our setting.
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http://dx.doi.org/10.1111/jon.12764DOI Listing
November 2020

Diagnostic Accuracy and Time-Saving Effects of Point-of-Care Ultrasonography in Patients With Small Bowel Obstruction: A Prospective Study.

Ann Emerg Med 2020 02 23;75(2):246-256. Epub 2019 Jul 23.

The George Washington University Medical Center, Washington, DC; Massachusetts General Hospital-Harvard Medical School, Boston, MA. Electronic address:

Study Objective: We evaluate the accuracy of point-of-care ultrasonography compared with computed tomographic (CT) scan and assess the potential time-saving effect of point-of-care ultrasonography in diagnosing small bowel obstruction.

Methods: This was a prospective observational study of a convenience sample of patients with suspected small bowel obstruction in an academic emergency department (ED). Physician sonographers were blinded to clinical data, laboratory results, and CT scan findings. Point-of-care ultrasonographic findings of small bowel obstruction was the primary outcome, defined as bowel-loop diameter greater than or equal to 25 mm with abnormal peristalsis. Maximum bowel dilatation, visible peristalsis, interluminal free fluid, and bowel wall thickness were evaluated. Time to completion of imaging results was abstracted from the medical records for each imaging modality.

Results: The study included 125 patients (median age 54.0 years [interquartile range 43 to 63 years]; 46% men), of whom 32 (25.6%) had small bowel obstruction, and 9 (7.2%) underwent surgery for it. Overall, the sensitivity of point-of-care ultrasonography for small bowel obstruction was 87.5% (95% confidence interval 71.0% to 96.5%), and specificity was 75.3% (95% confidence interval 65.2% to 83.6%). The area under the receiver operating characteristic curve to accurately predict small bowel obstruction was 0.74 (95% confidence interval 0.66 to 0.82). Results were similar across evaluated subgroups, including physician training level. The average time to obtain a CT scan report was 3 hours, 42 minutes; obtaining an abdominal radiograph took 1 hour, 38 minutes; and the mean elapsed time to complete point-of-care ultrasonography was 11 minutes.

Conclusion: In ED patients with suspected small bowel obstruction, point-of-care ultrasonography has a reasonably high accuracy in diagnosing small bowel obstruction compared with CT scan, and may substantially decrease the time to diagnosis.
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http://dx.doi.org/10.1016/j.annemergmed.2019.05.031DOI Listing
February 2020

Direct Observation Assessment of Ultrasound Competency Using a Mobile Standardized Direct Observation Tool Application With Comparison to Asynchronous Quality Assurance Evaluation.

AEM Educ Train 2019 Apr 19;3(2):172-178. Epub 2019 Feb 19.

Department of Emergency Medicine The George Washington University Washington DC.

Objectives: Competency assessment is a key component of point-of-care ultrasound (POCUS) training. The purpose of this study was to design a smartphone-based standardized direct observation tool (SDOT) and to compare a faculty-observed competency assessment at the bedside with a blinded reference standard assessment in the quality assurance (QA) review of ultrasound images.

Methods: In this prospective, observational study, an SDOT was created using SurveyMonkey containing specific scoring and evaluation items based on the Council of Emergency Medicine Residency-Academy of Emergency Ultrasound: Consensus Document for the Emergency Ultrasound Milestone Project. Ultrasound faculty used the mobile phone-based data collection tool as an SDOT at the bedside when students, residents, and fellows were performing one of eight core POCUS examinations. Data recorded included demographic data, examination-specific data, and overall quality measures (on a scale of 1-5, with 3 and above being defined as adequate for clinical decision making), as well as interpretation and clinical knowledge. The POCUS examination itself was recorded and uploaded to QPath, a HIPAA-compliant ultrasound archive. Each examination was later reviewed by another faculty blinded to the result of the bedside evaluation. The agreement of examinations scored adequate (3 and above) in the two evaluation methods was the primary outcome.

Results: A total of 163 direct observation evaluations were collected from 23 EM residents (93 SDOTs [57%]), 14 students (51 SDOTs [31%]), and four fellows (19 SDOTs [12%]). The trainees were evaluated on completing cardiac (54 [33%]), focused assessment with sonography for trauma (34 [21%]), biliary (25 [15%]), aorta (18 [11%]), renal (12 [7%]), pelvis (eight [5%]), deep vein thrombosis (seven [4%]), and lung scan (5 [3%]). Overall, the number of observed agreements between bedside and QA assessments was 81 (87.1% of the observations) for evaluating the quality of images (scores 1 and 2 vs. scores 3, 4, and 5). The strength of agreement is considered to be "fair" (κ = 0.251 and 95% confidence interval [CI] = 0.02-0.48). Further agreement assessment demonstrated a fair agreement for images taken by residents and students and a "perfect" agreement in images taken by fellows. Overall, a "moderate" inter-rater agreement was found in 79.1% for the accuracy of interpretation of POCUS scan (e.g., true positive, false negative) during QA and bedside evaluation (κ = 0.48, 95% CI = 0.34-0.63). Faculty at the bedside and QA assessment reached a moderate agreement on interpretations noted by residents and students and a "good" agreement on fellows' scans.

Conclusion: Using a bedside SDOT through a mobile SurveyMonkey platform facilitates assessment of competency in emergency ultrasound learners and correlates well with traditional competency evaluation by asynchronous weekly image review QA.
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http://dx.doi.org/10.1002/aet2.10324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457355PMC
April 2019

Multiplex polymerase chain reaction test to diagnose infectious diarrhea in the emergency department.

Am J Emerg Med 2019 07 12;37(7):1368-1370. Epub 2018 Dec 12.

The George Washington University, School of Medicine & Health Sciences, United States of America. Electronic address:

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http://dx.doi.org/10.1016/j.ajem.2018.12.019DOI Listing
July 2019

Enhanced Point-of-Care Ultrasound Applications by Integrating Automated Feature-Learning Systems Using Deep Learning.

J Ultrasound Med 2019 Jul 13;38(7):1887-1897. Epub 2018 Nov 13.

Department of Emergency Medicine, University of South Carolina School of Medicine, Columbia, South Carolina, USA.

Recent applications of artificial intelligence (AI) and deep learning (DL) in health care include enhanced diagnostic imaging modalities to support clinical decisions and improve patients' outcomes. Focused on using automated DL-based systems to improve point-of-care ultrasound (POCUS), we look at DL-based automation as a key field in expanding and improving POCUS applications in various clinical settings. A promising additional value would be the ability to automate training model selections for teaching POCUS to medical trainees and novice sonologists. The diversity of POCUS applications and ultrasound equipment, each requiring specialized AI models and domain expertise, limits the use of DL as a generic solution. In this article, we highlight the most advanced potential applications of AI in POCUS tailored to high-yield models in automated image interpretations, with the premise of improving the accuracy and efficacy of POCUS scans.
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http://dx.doi.org/10.1002/jum.14860DOI Listing
July 2019

Enhanced Point-of-Care Ultrasound Applications by Integrating Automated Feature-Learning Systems Using Deep Learning.

J Ultrasound Med 2019 Jul 13;38(7):1887-1897. Epub 2018 Nov 13.

Department of Emergency Medicine, University of South Carolina School of Medicine, Columbia, South Carolina, USA.

Recent applications of artificial intelligence (AI) and deep learning (DL) in health care include enhanced diagnostic imaging modalities to support clinical decisions and improve patients' outcomes. Focused on using automated DL-based systems to improve point-of-care ultrasound (POCUS), we look at DL-based automation as a key field in expanding and improving POCUS applications in various clinical settings. A promising additional value would be the ability to automate training model selections for teaching POCUS to medical trainees and novice sonologists. The diversity of POCUS applications and ultrasound equipment, each requiring specialized AI models and domain expertise, limits the use of DL as a generic solution. In this article, we highlight the most advanced potential applications of AI in POCUS tailored to high-yield models in automated image interpretations, with the premise of improving the accuracy and efficacy of POCUS scans.
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http://dx.doi.org/10.1002/jum.14860DOI Listing
July 2019

Ultrasound-guided intravenous access in adults using SonoStik, a novel encapsulated sterile guidewire: A prospective cohort trial.

J Vasc Access 2018 Sep 12;19(5):441-445. Epub 2018 Mar 12.

1 Department of Emergency Medicine, The George Washington University Medical Center, Washington, DC, USA.

Purpose: We evaluated the performance of an encapsulated guidewire designed for single-handed use with ultrasound-guided vascular access (SonoStik) with Seldinger technique, as compared with conventional intravenous catheters placed under ultrasound guidance in healthy subjects.

Methods: This is a prospective cohort trial in healthy subjects in which each subject served as his/her own control by having a SonoStik ultrasound intravenous cannulation placed in one arm and a conventionally placed, standard ultrasound intravenous cannulation placed in the other arm. The basilic vein was used because it is a non-visible and non-palpable vein. Emergency department technicians with extensive experience in ultrasound-guided intravenous access performed the procedures. The first-attempt success rate of intravenous-guided intravenous by using the SonoStik was compared to the standard ultrasound intravenous cannulation in adult healthy subjects. The secondary outcomes including time of procedure, technicians' and subjects' satisfaction, and complications were compared in both arms of the study.

Results: A total of 24 volunteers with a mean age of 22.7 years were enrolled. Four emergency department technicians with extensive prior experience with ultrasound-guided intravenous access but with no prior experience using the SonoStik device performed the procedures. The first-attempt success was 83.3% with the use of SonoStik ultrasound intravenous cannulation compared to 95.8% with the standard ultrasound intravenous cannulation. There was a mean of 1.14 insertions per each successful placement in the SonoStik group compared to 1.04 insertions by using the standard catheters (mean differences = -0.1; 95% confidence interval = -0.6 to 0.4). There were no complications in either SonoStik or the standard ultrasound intravenous cannulation group. The mean time of insertion using SonoStik was slightly longer compared to standard ultrasound intravenous cannulation (143.3 vs 109.7 s).

Conclusion: This study demonstrated that emergency department technicians skilled in ultrasound-guided intravenous access could successfully place SonoStik 83.3% of the time in vessels that were unable to be palpated or visualized. Compared to standard ultrasound intravenous cannulation, the odds ratio of successful cannulation with SonoStik was 0.91 (95% confidence interval = 0.04-17.5). In all cases, the time required to successfully insert SonoStik was less than 4 min from tourniquet application to catheter advancement to hub, with a mean time of less than 2.5 min.
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http://dx.doi.org/10.1177/1129729818758228DOI Listing
September 2018

Caring for VIPs in the emergency department: Are they VIPs or patients?

Am J Emerg Med 2018 May 23;36(5):895-896. Epub 2017 Sep 23.

Department of Emergency Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, United States.

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http://dx.doi.org/10.1016/j.ajem.2017.09.037DOI Listing
May 2018
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