BackgroundAccess to ultrasound has increased significantly in resource-limited settings, including the developing world; however, there remains a lack of sonography education and ultrasound-trained physician support in developing countries. To further investigate this potential knowledge gap, our primary objective was to assess perceived barriers to ultrasound use in resource-limited settings by surveying care providers who practice in low- and middle-income settings.MethodsA 25-question online survey was made available to health care providers who work with an ultrasound machine in low- and middle-income countries (LMICs), including doctors, nurses, technicians, and clinical officers. This was a convenience sample obtained from list-serves of ultrasound and radiologic societies. The survey was analyzed, and descriptive results were obtained.ResultsOne hundred and thirty-eight respondents representing 44 LMICs including countries from the continents of Africa, South America, and Asia completed the survey, with a response rate of 9.6 %. Ninety-one percent of the respondents were doctors, and 9 % were nurses or other providers. Applications for ultrasound were diverse, including obstetrics (75 %), DVT evaluation (51 %), abscess evaluation (54 %), cardiac evaluation (64 %), inferior vena cava (IVC) assessment (49 %), Focused Assessment Sonography for Trauma (FAST) exam (64 %), biliary tree assessment (54 %), and other applications. The respondents identified the following barriers to use of ultrasound: lack of training (60 %), lack of equipment (45 %), ultrasound machine malfunction (37 %), and lack of ultrasound maintenance capability (47 %). Seventy-four percent of the respondents wished to have further training in ultrasound, and 82 % were open to receiving distance learning or telesonography training. Subjects used communication tools including Skype, Dropbox, emailed photos, and picture archiving and communication system (PACS) as ways to communicate and receive feedback on ultrasound images.ConclusionsHealth care providers in the developing world identify lack of training as a primary barrier to regular use of ultrasound in their practice. While equipment requirements including maintenance and cost of machines are also important factors, future research is warranted on best practices for training methods, including telesonography and distance learning to enhance ultrasound use in low-resource settings.

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IntroductionIn low-resource settings it is not always possible to acquire the information required to diagnose acute respiratory distress syndrome (ARDS). Ultrasound and pulse oximetry, however, may be available in these settings. This study was designed to test whether pulmonary ultrasound and pulse oximetry could be used in place of traditional radiographic and oxygenation evaluation for ARDS.MethodsThis study was a prospective, single-center study in the ICU of Harborview Medical Center, a referral hospital in Seattle, Washington, USA. Bedside pulmonary ultrasound was performed on ICU patients receiving invasive mechanical ventilation. Pulse oximetric oxygen saturation (SpO2), partial pressure of oxygen (PaO2), fraction of inspired oxygen (FiO2), provider diagnoses, and chest radiograph closest to time of ultrasound were recorded or interpreted.ResultsOne hundred and twenty three ultrasound assessments were performed on 77 consecutively enrolled patients with respiratory failure. Oxygenation and radiographic criteria for ARDS were met in 35 assessments. Where SpO2 ≤ 97 %, the Spearman rank correlation coefficient between SpO2/FiO2 and PaO2/FiO2 was 0.83, p < 0.0001. The sensitivity and specificity of the previously reported threshold of SpO2/FiO2 ≤ 315 for PaO2/FiO2 ≤ 300 was 83 % (95 % confidence interval (CI) 68–93), and 50 % (95 % CI 1–99), respectively. Sensitivity and specificity of SpO2/FiO2 ≤ 235 for PaO2/FiO2 ≤ 200 was 70 % (95 % CI 47–87), and 90 % (95 % CI 68–99), respectively. For pulmonary ultrasound assessments interpreted by the study physician, the sensitivity and specificity of ultrasound interstitial syndrome bilaterally and involving at least three lung fields were 80 % (95 % CI 63–92) and 62 % (95 % CI 49–74) for radiographic criteria for ARDS. Combining SpO2/FiO2 with ultrasound to determine oxygenation and radiographic criteria for ARDS, the sensitivity was 83 % (95 % CI 52–98) and specificity was 62 % (95 % CI 38–82). For moderate–severe ARDS criteria (PaO2/FiO2 ≤ 200), sensitivity was 64 % (95 % CI 31–89) and specificity was 86 % (95 % CI 65–97). Excluding repeat assessments and independent interpretation of ultrasound images did not significantly alter the sensitivity measures.ConclusionsPulse oximetry and pulmonary ultrasound may be useful tools to screen for, or rule out, impaired oxygenation or lung abnormalities consistent with ARDS in under-resourced settings where arterial blood gas testing and chest radiography are not readily available.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0995-5) contains supplementary material, which is available to authorized users.