Sachita Shah

Correlation of Optic Nerve Sheath Diameter with Direct Measurement of Intracranial Pressure

BACKGROUND Measurements of the optic nerve sheath diameter (ONSD) using bedside ultrasound (US) have been shown to correlate with clinical and radiologic signs and symptoms of increased intracranial pressure (ICP). OBJECTIVES Previous literature has identified 5 mm as the ONSD measurement above which patients exhibit either clinical or radiologic signs of elevated ICP. The goals of this study were to evaluate the association between ONSD and ICP and to validate the commonly used ONSD threshold of 5 mm using direct measurements of ICP as measured by ventriculostomy. METHODS A prospective blinded observational study was performed using a convenience sample of adult patients in both the emergency department (ED) and the neurologic intensive care unit (ICU) who had invasive intracranial monitors placed as part of their clinical care. Ocular USs were performed with a 10(-5) MHz linear probe. Emergency physicians (EPs) with previous ocular US experience performed ONSD measurements while blinded to the contemporaneous ICP reading obtained directly from invasive monitoring. The association between ONSD and ICP was assessed with the Spearman rank correlation coefficient, and a receiver operator characteristic (ROC) curve was created to determine the optimal ONSD cutoff to detect ICP > 20 cm H2O. RESULTS Thirty-eight ocular USs were performed on 15 individual patients. Spearman rank correlation coefficient of ONSD and ICP was 0.59 (p < 0.0005) demonstrating a significant positive correlation. An ROC curve was created to assess the ability of ONSD to distinguish an abnormal ICP greater than 20 cm H2O. The area under the ROC curve was 0.93 (95% confidence interval [CI] = 0.84 to 0.99). Based on inspection of the ROC curve, ONSD > 5 mm performed well to detect ICP > 20 cm H(2)O with a sensitivity of 88% (95% CI = 47% to 99%) and specificity of 93% (95% CI = 78% to 99%). CONCLUSIONS Using an ROC curve the authors systematically confirmed the commonly used threshold of ONSD > 5 mm to detect ICP > 20 cm H2O. This study directly correlates ventriculostomy measurements of ICP with US ONSD measurements and provides further support for the use of ONSD measurements as a noninvasive test for elevated ICP.

Review article: Use of ultrasound in the developing world

As portability and durability improve, bedside, clinician-performed ultrasound is seeing increasing use in rural, underdeveloped parts of the world. Physicians, nurses and medical officers have demonstrated the ability to perform and interpret a large variety of ultrasound exams, and a growing body of literature supports the use of point-of-care ultrasound in developing nations. We review, by region, the existing literature in support of ultrasound use in the developing world and training guidelines currently in use, and highlight indications for emergency ultrasound in the developing world. We suggest future directions for bedside ultrasound use and research to improve diagnostic capacity and patient care in the most remote areas of the globe.

Development of an ultrasound training curriculum in a limited resource international setting: successes and challenges of ultrasound training in rural Rwanda

BackgroundOver the last decade, the diffusion of ultrasound technology to nontraditional users has been rapid and far-reaching. Much research and effort has been focused on developing an ultrasound curriculum and training and practice guidelines for these users. The potential for this diagnostic tool is not limited to the developed world and in many respects ultrasound is adaptable to limited resource international settings. However, needs-based curriculum development, training guidelines, impact on resource utilization, and sustainability are not well studied in the developing world setting.AimsWe review one method of introducing applicable curriculum, training local providers, and sustaining a comprehensive ultrasound program.MethodsTwo rural Rwandan hospitals affiliated with a US nongovernmental organization participated in a pilot ultrasound training program. Prior to introduction of ultrasound, local physicians completed a survey to determine the perceived importance of various ultrasound scan types. Hospital records were also reviewed to determine disease and presenting complaint prevalence as part of an initial needs assessment and to define our curriculum. We hypothesized certain studies would be more utilized and have a greater impact given available treatment resources.ResultsWe review here the choice of curriculum, the training plan, helpful equipment specifications, and implementation of ongoing measures of quality assessment and sustainability. Our 9-week lecture and practice-based ultrasound curriculum included obstetrics, abdominal, renal, hepatobiliary, cardiac, pleural, vascular, and procedural ultrasound.ConclusionsWhile ultrasound as a diagnostic modality for resource-poor parts of the world has generated interest for years, recent advances in technology have brought ultrasound again to the forefront as a sustainable and high impact technology for resource-poor developing world nations. From our experience in rural Rwanda, we conclude that ultrasound remains helpful in patient care and the diagnostic impact is enhanced by choosing the correct applications to implement. We also conclude that ultrasound is a teachable skill, with a several week intensive training period involving hands-on practice skills and plans for long-term learning and have begun a second phase of evaluating knowledge retention for this introductory program.

Impact of the introduction of ultrasound services in a limited resource setting: rural Rwanda 2008

BackgroundOver the last decade, utilization of ultrasound technology by non-radiologist physicians has grown. Recent advances in affordability, durability, and portability have brought ultrasound to the forefront as a sustainable and high impact technology for use in developing world clinical settings as well. However, ultrasounds impact on patient management plans, program sustainability, and which ultrasound applications are useful in this setting has not been well studied.MethodsUltrasound services were introduced at two rural Rwandan district hospitals affiliated with Partners in Health, a US nongovernmental organization. Data sheets for each ultrasound scan performed during routine clinical care were collected and analyzed to determine patient demographics, which ultrasound applications were most frequently used, and whether the use of the ultrasound changed patient management plans. Ultrasound scans performed by the local physicians during the post-training period were reviewed for accuracy of interpretation and image quality by an ultrasound fellowship trained emergency medicine physician from the United States who was blinded to the original interpretation.ResultsAdult women appeared to benefit most from the presence of ultrasound services. Of the 345 scans performed during the study period, obstetrical scanning was the most frequently used application. Evaluation of gestational age, fetal head position, and placental positioning were the most common findings. However, other applications used included abdominal, cardiac, renal, pleural, procedural guidance, and vascular ultrasounds.Ultrasound changed patient management plans in 43% of total patients scanned. The most common change was to plan a surgical procedure. The ultrasound program appears sustainable; local staff performed 245 ultrasound scans in the 11 weeks after the departure of the ultrasound instructor. Post-training scan review showed the concordance rate of interpretation between the Rwandese physicians and the ultrasound-trained quality review physicians was 96%.ConclusionWe suggest ultrasound is a useful modality that particularly benefits womens health and obstetrical care in the developing world. Ultrasound services significantly impact patient management plans especially with regards to potential surgical interventions. After an initial training period, it appears that an ultrasound program led by local health care providers is sustainable and lead to accurate diagnoses in a rural international setting.

Ultrasound Assessment of Severe Dehydration in Children With Diarrhea and Vomiting

OBJECTIVES The objective of this study was to determine the test characteristics for two different ultrasound (US) measures of severe dehydration in children (aorta to inferior vena cava [IVC] ratio and IVC inspiratory collapse) and one clinical measure of severe dehydration (the World Health Organization [WHO] dehydration scale). METHODS The authors enrolled a prospective cohort of children presenting with diarrhea and/or vomiting to three rural Rwandan hospitals. Children were assessed clinically using the WHO scale and then underwent US of the IVC by a second clinician. All children were weighed on admission and then fluid-resuscitated according to standard hospital protocols. A percent weight change between admission and discharge of greater than 10% was considered the criterion standard for severe dehydration. Receiver operating characteristic (ROC) curves were created for each of the three tests of severe dehydration compared to the criterion standard. RESULTS Children ranged in age from 1 month to 10 years; 29% of the children had severe dehydration according to the criterion standard. Of the three different measures of dehydration tested, only US assessment of the aorta/IVC ratio had an area under the ROC curve statistically different from the reference line. At its best cut-point, the aorta/IVC ratio had a sensitivity of 93% and specificity of 59%, compared with 93% and 35% for IVC inspiratory collapse and 73% and 43% for the WHO scale. CONCLUSIONS Ultrasound of the aorta/IVC ratio can be used to identify severe dehydration in children presenting with acute diarrhea and may be helpful in guiding clinical management.

Comparing the accuracy of the three popular clinical dehydration scales in children with diarrhea

BackgroundDehydration due to acute gastroenteritis is one of the leading causes of mortality in children worldwide. The World Health Organization (WHO) scale, the Gorelick scale, and the Clinical Dehydration Scale (CDS) were created to estimate percentage dehydration in children with gastroenteritis based on clinical signs. Of these, only the CDS has been prospectively validated against a valid gold standard, though never in low- and middle-income countries. The purpose of this study is to determine whether these clinical scales can accurately assess dehydration status in children when performed by nurses or general physicians in a low-income country.MethodsWe prospectively enrolled a non-consecutive sample of children presenting to three Rwandan hospitals with diarrhea and/or vomiting. A health care provider documented clinical signs on arrival and weighed the patient using a standard scale. Once admitted, the patient received rehydration according to standard hospital protocol and was weighed again at hospital discharge. Receiver operating characteristic (ROC) curves were created for each of the three scales compared to the gold standard, percent weight change with rehydration. Sensitivity, specificity, and likelihood ratios were calculated based on the best cutoff points of the ROC curves.ResultsWe enrolled 73 children, and 49 children met eligibility criteria. Based on our gold standard, the children had a mean percent dehydration of 5% on arrival. The WHO scale, Gorelick scale, and CDS did not have an area under the ROC curve statistically different from the reference line. The WHO scale had sensitivities of 79% and 50% and specificities of 43% and 61% for severe and moderate dehydration, respectively; the 4- and 10-point Gorelick scale had sensitivities of 64% and 21% and specificities of 69% and 89%, respectively, for severe dehydration, while the same scales had sensitivities of 68% and 82% and specificities of 41% and 35% for moderate dehydration; the CDS had a sensitivity of 68% and specificity of 45% for moderate dehydration.ConclusionIn this sample of children, the WHO scale, Gorelick scale, and CDS did not provide an accurate assessment of dehydration status when used by general physicians and nurses in a developing world setting.

Individual patient data systematic review and meta-analysis of optic nerve sheath diameter ultrasonography for detecting raised intracranial pressure: protocol of the ONSD research group

BackgroundThe purpose of the optic nerve sheath diameter (ONSD) research group project is to establish an individual patient-level database from high quality studies of ONSD ultrasonography for the detection of raised intracranial pressure (ICP), and to perform a systematic review and an individual patient data meta-analysis (IPDMA), which will provide a cutoff value to help physicians making decisions and encourage further research. Previous meta-analyses were able to assess the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP but failed to determine a precise cutoff value. Thus, the ONSD research group was founded to synthesize data from several recent studies on the subject and to provide evidence on the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP.MethodsThis IPDMA will be conducted in different phases. First, we will systematically search for eligible studies. To be eligible, studies must have compared ONSD ultrasonography to invasive intracranial devices, the current reference standard for diagnosing raised ICP. Subsequently, we will assess the quality of studies included based on the QUADAS-2 tool, and then collect and validate individual patient data. The objectives of the primary analyses will be to assess the diagnostic accuracy of ONSD ultrasonography and to determine a precise cutoff value for detecting raised ICP. Secondly, we will construct a logistic regression model to assess whether patient and study characteristics influence diagnostic accuracy.DiscussionWe believe that this IPD MA will provide the most reliable basis for the assessment of diagnostic accuracy of ONSD ultrasonography for detecting raised ICP and to provide a cutoff value. We also hope that the creation of the ONSD research group will encourage further study.Systematic review registrationPROSPERO registration number: CRD42012003072

Point‐of‐care ultrasound education for non‐physician clinicians in a resource‐limited emergency department

To describe the outcomes and curriculum components of an educational programme to train non‐physician clinicians working in a rural, Ugandan emergency department in the use of POC ultrasound.

Impact of point-of-care ultrasound training on surgical residents' confidence.

OBJECTIVE Point-of-care ultrasound (POCUS) is a vital tool for diagnosis and management of critically ill patients, particularly in resource-limited settings where access to diagnostic imaging may be constrained. We aimed to develop a novel POCUS training curriculum for surgical practice in the United States and in resource-limited settings in low- and middle-income countries and to determine its effect on surgical resident self-assessments of efficacy and confidence. DESIGN We conducted an observational cohort study evaluating a POCUS training course that comprised 7 sessions of 2 hours each with didactics and proctored skills stations covering ultrasound applications for trauma (Focused Assessement with Sonography for Trauma (FAST) examination), obstetrics, vascular, soft tissue, regional anesthesia, focused echocardiography, and ultrasound guidance for procedures. Surveys on attitudes, prior experience, and confidence in point-of-care ultrasound applications were conducted before and after the course. SETTING General Surgery Training Program in Seattle, Washington. PARTICIPANTS A total of 16 residents participated in the course; 15 and 10 residents completed the precourse and postcourse surveys, respectively. RESULTS The mean composite confidence score from pretest compared with posttest improved from 23.3 (±10.2) to 37.8 (±6.7). Median confidence scores (1-6 scale) improved from 1.5 to 5.0 in performance of FAST (p < 0.001). Residents reported greater confidence in their ability to identify pericardial (2 to 4, p = 0.009) and peritoneal fluid (2 to 4.5, p < 0.001), to use ultrasound to guide procedures (3.5 to 4.0, p = 0.008), and to estimate ejection fraction (1 to 4, p = 0.004). Both before and after training, surgical residents overwhelmingly agreed with statements that ultrasound would improve their US-based practice, make them a better surgical resident, and improve their practice in resource-limited settings. CONCLUSIONS After a POCUS course designed specifically for surgeons, surgical residents had improved self-efficacy and confidence levels across a broad range of skills.

The BUDDY (Bedside Ultrasound to Detect Dehydration in Youth) study

BackgroundPrior research suggests that the ratio of the ultrasound-measured diameter of the inferior vena cava to the aorta correlates with the level of dehydration in children. This study was designed to externally validate this and to access the accuracy of the ultrasound measured inspiratory IVC collapse and physician gestalt to predict significant dehydration in children in the emergency department.MethodsWe prospectively enrolled a non-consecutive cohort of children ≤18 years old. Patient weight, ultrasound measurements of the IVC and Ao, and physician gestalt were recorded. The percent weight change from presentation to discharge was used to calculate the degree of dehydration. A weight change of ≥5% was considered clinically significant dehydration. Receiver operating characteristic (ROC) curves were constructed for each of the ultrasound measurements and physician gestalt. Sensitivity (SN) and specificity (SP) were calculated based on previously established cutoff points of the IVC/Ao ratio (0.8), the IVC collapsibility index of 50%, and a new cut off point of IVC collapsibility index of 80% or greater. Intra-class correlation coefficients were calculated to assess the degree of inter-rater reliability between ultrasound observers.ResultsOf 113 patients, 10.6% had significant dehydration. The IVC/Ao ratio had an area under the ROC curve (AUC) of 0.72 (95% CI 0.53 to 0.91) and, with a cutoff of 0.8, produced a SN of 67% and a SP of 71% for the diagnosis of significant dehydration. The IVC collapsibility index of 50% had an AUC of 0.58 (95% CI 0.44 to 0.72) and, with a cutoff of 80% collapsibility, produced a SN of 83% and a SP of 42%. The intra-class correlation coefficient was 0.83 for the IVC/Ao ratio and 0.70 for the IVC collapsibility. Physician gestalt had an AUC of 0.61 (95% CI 0.44 to 0.78) and, with a cutoff point of 5, produced a SN of 42% and a SP of 65%.ConclusionsThe ultrasound-measured IVC/Ao ratio is a modest predictor of significant dehydration in children. The inspiratory IVC collapse and physician gestalt were poor predictors of the actual level of dehydration in this study.