Utility of ultrasound in managing acute medical conditions in space: a scoping review.

BACKGROUND: In long-distance spaceflight, the challenges of communication delays and the impracticality of rapid evacuation necessitate the management of medical emergencies by onboard physicians. Consequently, these physicians must be proficient in tools, such as ultrasound, which has proven itself a strong diagnostic imaging tool in space. Yet, there remains a notable gap in the discourse surrounding its efficacy in handling acute medical scenarios. This scoping review aims to present an updated analysis of the evidence supporting the role of ultrasound in diagnosing acute conditions within microgravity environments. METHODS: A systematic search was executed across three bibliographic databases: PubMed, EMBASE (Embase.com), and the Web of Science Core Collection. We considered articles published up to February 25, 2023, that highlighted the application of ultrasound in diagnosing acute medical conditions in either microgravity or microgravity-simulated settings. Exclusions were made for review papers, abstracts, and in-vitro studies. RESULTS: After removing duplicates, and filtering papers by pre-determined criteria, a total of 15 articles were identified that discuss the potential use of ultrasound in managing acute medical conditions in space. The publication date of these studies ranged from 1999 to 2020. A relatively similar proportion of these studies were conducted either on the International Space Station or in parabolic flight, with one performed in supine positioning to simulate weightlessness. The included studies discuss acute pathologies, such as abdominal emergencies, decompression sickness, deep venous thrombosis, acute lung pathologies, sinusitis, musculoskeletal trauma, genitourinary emergencies, and ocular emergencies. CONCLUSIONS: While ultrasound has shown promise in addressing various acute conditions, significant knowledge gaps remain, especially in gastrointestinal, cardiac, vascular, and reproductive emergencies. As we venture further into space, expanding our medical expertise becomes vital to ensure astronaut safety and mission success.

Ultrasound detected increase in optic disk height to identify elevated intracranial pressure: a systematic review.

BACKGROUND: Elevated intracranial pressure (eICP) is a serious medical emergency that requires prompt identification and monitoring. The current gold standards of eICP detection require patient transportation, radiation, and can be invasive. Ocular ultrasound has emerged as a rapid, non-invasive, bedside tool to measure correlates of eICP. This systematic review seeks to explore the utility of ultrasound detected optic disc elevation (ODE) as an ultrasonographic finding of eICP and to study its sensitivity and specificity as a marker of eICP. METHODS: This systematic review followed the preferred reporting items for systematic reviews and meta-analyses guidelines. We systematically searched PubMed, EMBASE, and Cochrane Central for English articles published before April 2023; yielding 1,919 total citations. After eliminating duplicates, and screening the records, we identified 29 articles that addressed ultrasonographically detected ODE. RESULTS: The 29 articles included a total of 1249 adult and pediatric participants. In patients with papilledema, the mean ODE ranged between 0.6 mm and 1.2 mm. Proposed cutoff values for ODE ranged between 0.3 mm and 1 mm. The majority of studies reported a sensitivity between 70 and 90%, and specificity ranged from 69 to 100%, with a majority of studies reporting a specificity of 100%. CONCLUSIONS: ODE and ultrasonographic characteristics of the optic disc may aid in differentiating papilledema from other conditions. Further research on ODE elevation and its correlation with other ultrasonographic signs is warranted as a means to increase the diagnostic accuracy of ultrasound in the setting of eICP.

Using tele-ultrasound to teach medical students: A randomised control equivalence study.

Objectives: Undergraduate ultrasound education is becoming increasingly important, but its expansion is limited by time, space and the availability of trained faculty. In order to validate an alternative and more accessible teaching model, our aim was to assess whether combining teleguidance and peer-assisted learning to teach ultrasound is as effective as traditional in-person methods. Methods: Peer instructors taught 47 second-year medical students ocular ultrasound via either teleguidance or traditional in-person methods. Proficiency was assessed using a multiple-choice knowledge test and objective structured clinical examination (OSCE). Confidence, overall experience, and experience with a peer instructor were measured using a 5-point Likert scale. Two one-sided t-tests were used to measure equivalency between the two groups. The null hypothesis that the two groups were not different was rejected when P < 0.05. Results: The teleguidance group performed as well as the traditional in-person group in terms of knowledge change, confidence change, OSCE time and OSCE score (p = 0.011, p = 0.006, p = 0.005 and  = 0.004, respectively, indicating the two groups are statistically equivalent). The teleguidance group rated the experience highly overall (4.06/5), but less than the traditional group (4.47/5; P = 0.448, indicating statistical difference). Peer instruction was rated 4.35/5 overall. Conclusion: Peer-instructed teleguidance was equivalent to in-person instruction with respect to knowledge change, confidence gain and OSCE performance in basic ocular ultrasound.

Feasibility of patient-performed lung ultrasound self-exams (Patient-PLUS) as a potential approach to telemedicine in heart failure.

AIMS: Patient-performed lung ultrasound (LUS) in a heart failure (HF) telemedicine model may be used to monitor worsening pulmonary oedema and to titrate therapy, potentially reducing HF admission. The aim of the study was to assess the feasibility of training HF patients to perform a LUS self-exam in a telemedicine model. METHODS AND RESULTS: A pilot study was conducted at a public hospital involving subjects with a history of HF. After a 15 min training session involving a tutorial video, subjects performed a four-zone LUS using a handheld ultrasound. Exams were saved on a remote server and independently reviewed by two LUS experts. Studies were determined interpretable according to a strict definition: the presence of an intercostal space, and the presence of A-lines, B-lines, or both. Subjects also answered a questionnaire to gather feedback and assess self-efficacy. The median age of 44 subjects was 53 years (range, 36-64). Thirty (68%) were male. Last educational level attained was high school or below for 31 subjects (70%), and one-third used Spanish as their preferred language. One hundred fifty of 175 lung zones (85%) were interpretable, with expert agreement of 87% and a kappa of 0.49. 98% of subjects reported that they could perform this LUS self-exam at home. CONCLUSIONS: This pilot study reports that training HF patients to perform a LUS self-exam is feasible, with reported high self-efficacy. This supports further investigation into a telemedicine model using LUS to reduce emergency department visits and hospitalizations associated with HF.

A Novel Three-Dimensional-Printed Ultrasound-Guided Hip Arthrocentesis Model.

When evaluating patients with hip pain, clinicians may be trained to both evaluate for a hip effusion and perform ultrasound-guided arthrocentesis to evaluate the etiology of the effusion. We present a novel 3-dimensional-printed hip arthrocentesis model, which can be used to train clinicians to perform both tasks under ultrasound guidance. Our model uses a combination of a 3-dimensional-printed hip joint, as well as readily available materials such as an infant Ambu (Ballerup, Denmark) bag, syringe, intravenous line kit, and silicone. We present our experience so that others may use and adapt our model for their training purposes.

Pseudoaneurysm of the Dorsalis Pedis Artery Diagnosed on Point-of-Care Ultrasound.

A 46-year-old man presented with a painless mass on his dorsal right foot one week after striking it on a door. A traumatic hematoma was suspected, and needle aspiration of the mass is considered. However, point-of-care ultrasound performed by the emergency physician identified a pseudoaneurysm of the dorsalis pedis artery, a rare condition that can occur after minor trauma or iatrogenic intervention. This report demonstrates how point-of-care ultrasound can be used to identify a pseudoaneurysm of the lower extremity, thereby expediting emergency department workup and preventing potentially dangerous diagnostic procedures.

Passive Leg Raise: Feasibility and Safety of the Maneuver in Patients With Undifferentiated Shock.

PURPOSE: Passive leg raise (PLR), in combination with technologies capable of capturing stroke volume changes, has been widely adopted in the management of shock. However, dedicated evaluation of safety, feasibility, and receptiveness of patients and nursing staff to PLR maneuver is missing. METHODS: A noninterventional, prospective trial recruited adult patients with onset of undifferentiated shock within 24 hours with persistent vasopressor requirements despite fluid resuscitation. A standardized PLR maneuver was used to compare two noninvasive hemodynamic monitoring systems, each without significant impact on the performance of the maneuver. Safety and efficacy of the PLR were evaluated via subjective and objective measures. Objective measures of patient comfort and tolerance were evaluated through changes in vital signs, sedation, and analgesia requirements. Nurses and awake patients completed surveys on their experience. RESULTS: Seventy-nine patients were enrolled. Testing was aborted in 2 cases for medical reasons (one patient developed rapid atrial fibrillation, second had profound desaturation). Of all, 5.4% of patients required additional vasopressor support after completion of the PLR maneuver due to persistent hypotension and 4.1% of patients required additional sedation. Among awake patients (N = 35), 6% reported pain and 29% reported discomfort. A total of 11% of nurses reported minor technical difficulties with the maneuver. CONCLUSION: Passive leg raise maneuver leads to a few serious but reversible complications in a selected population of hemodynamically unstable patients. Although it provides relevant diagnostic information, it may impact patient care. Treating physician should be aware of infrequent but possible complications and appreciate the impact of the maneuver on patients' comfort and nursing workload.

Effect of insonation angle on peak systolic velocity variation.

OBJECTIVES: As point of care ultrasound (POCUS) has become more integrated into emergency and critical care medicine, there has been increased interest in utilizing ultrasound to assess volume status. However, recent studies of carotid POCUS on volume status and fluid responsiveness fail to recognize the effect insonation angle has on their results. To address this, we studied the effect of insonation angle on peak systolic velocity (PSV) change associated with respiratory variation (RV) and passive leg raise (PLR). METHODS: Doppler measurements were obtained from 51 subjects presenting to the ED. Minimal and maximal PSV were obtained using insonation angles of 46°, 60°, and 90°. ∆PSV was calculated using PLR and RV as trial methods. Results were categorized into two groups, those with a ∆PSV > 10% and those with a ∆PSV ≤ 10%. ∆PSV mean and standard error, as well as measures of agreement were calculated. RESULTS: Mean ∆PSV associated with PLR test was 9% in the 46° and 60° groups, and 18% in the 90° group, with standard errors of 6, 7, and 14%, respectively. Using 46° as our relative gold standard, Kappa was 0.23 at 60° and 0.11 at 90° with RV as the trial method, and 0.23 at 60° and 0.01 at 90° with a PLR as the trial method. CONCLUSIONS: Variation in PSV is heavily dependent on insonation angle. There was only slight to fair agreement in ∆PSV among the various insonation angles. Further investigation of the optimal insonation angle to assess ∆PSV should be undertaken.

Point-of-Care Ultrasonography in the Diagnosis of Retinal Detachment, Vitreous Hemorrhage, and Vitreous Detachment in the Emergency Department.

Importance: Ocular symptoms represent approximately 2% to 3% of all emergency department (ED) visits. These disease processes may progress to permanent vision loss if not diagnosed and treated quickly. Use of ocular point-of-care ultrasonography (POCUS) may be effective for early and accurate detection of ocular disease. Objective: To perform a large-scale, multicenter study to determine the utility of POCUS for diagnosing retinal detachment, vitreous hemorrhage, and vitreous detachment in the ED. Design, Setting, and Participants: A prospective diagnostic study was conducted at 2 academic EDs and 2 county hospital EDs from February 3, 2016, to April 30, 2018. Patients who were eligible for inclusion were older than 18 years; were English- or Spanish-speaking; presented to the ED with ocular symptoms with concern for retinal detachment, vitreous hemorrhage, or vitreous detachment; and underwent an ophthalmologic consultation that included POCUS. Patients with ocular trauma or suspicion for globe rupture were excluded. The accuracy of the ultrasonographic diagnosis was compared with the criterion standard of the final diagnosis of an ophthalmologist who was masked to the POCUS findings. Seventy-five unique emergency medicine attending physicians, resident physicians, and physician assistants performed ocular ultrasonography. Exposure: Point-of-care ultrasonography performed by an emergency medicine attending physician, resident physician, or physician assistant. Main Outcomes and Measures: Sensitivity and specificity of POCUS in identifying retinal detachment, vitreous hemorrhage, and vitreous detachment in patients presenting to the ED with ocular symptoms. Results: Two hundred twenty-five patients were enrolled. Of these, the mean age was 51 years (range, 18-91 years) and 135 (60.0%) were men; ophthalmologists diagnosed 47 (20.8%) with retinal detachment, 54 (24.0%) with vitreous hemorrhage, and 34 (15.1%) with vitreous detachment. Point-of-care ultrasonography had an overall sensitivity of 96.9% (95% CI, 80.6%-99.6%) and specificity of 88.1% (95% CI, 81.8%-92.4%) for diagnosis of retinal detachment. For diagnosis of vitreous hemorrhage, the sensitivity of POCUS was 81.9% (95% CI, 63.0%-92.4%) and specificity was 82.3% (95% CI, 75.4%-87.5%). For vitreous detachment, the sensitivity was 42.5% (95% CI, 24.7%-62.4%) and specificity was 96.0% (95% CI, 91.2%-98.2%). Conclusions and Relevance: These findings suggest that emergency medicine practitioners can use POCUS to accurately identify retinal detachment, vitreous hemorrhage, and vitreous detachment. Point-of-care ultrasonography is not intended to replace the role of the ophthalmologist for definitive diagnosis of these conditions, but it may serve as an adjunct to help emergency medicine practitioners improve care for patients with ocular symptoms.

Time to correct the flow of corrected flow time.

Recently published study of Ma et al. evaluates two relatively novel measures of fluid responsiveness, carotid blood flow and corrected carotid flow time (ccFT). Both measures have been recently quoted as possibly useful, technically simple, and noninvasive dynamic tools in predicting fluid responsiveness. Recently, more research interest has been focused on ccFT and, intrigued by the data presented in this study, we discuss here the impact of the data presented in the paper of Ma et al. to the significance of this metric as a potential tool in the assessment of fluid responsiveness.

Simplified point-of-care ultrasound protocol to confirm central venous catheter placement: A prospective study.

BACKGROUND: The current standard for confirmation of correct supra-diaphragmatic central venous catheter (CVC) placement is with plain film chest radiography (CXR). We hypothesized that a simple point-of-care ultrasound (POCUS) protocol could effectively confirm placement and reduce time to confirmation. METHODS: We prospectively enrolled a convenience sample of patients in the emergency department and intensive care unit who required CVC placement. Correct positioning was considered if turbulent flow was visualized in the right atrium on sub-xiphoid, parasternal or apical cardiac ultrasound after injecting 5 cc of sterile, non-agitated, normal saline through the CVC. RESULTS: Seventy-eight patients were enrolled. POCUS had a sensitivity of 86.8% (95%CI 77.1%-93.5%) and specificity of 100% (95%CI 15.8%-100.0%) for identifying correct central venous catheter placement. Median POCUS and CXR completion were 16 minutes (IQR 10-29) and 32 minutes (IQR 19-45), respectively. CONCLUSION: Ultrasound may be an effective tool to confirm central venous catheter placement in instances where there is a delay in obtaining a confirmatory CXR.

Simplified point-of-care ultrasound protocol to confirm central venous catheter placement:A prospective study / 世界急诊医学杂志（英文）

@#BACKGROUND: The current standard for confirmation of correct supra-diaphragmatic central venous catheter (CVC) placement is with plain film chest radiography (CXR). We hypothesized that a simple point-of-care ultrasound (POCUS) protocol could effectively confirm placement and reduce time to confirmation. METHODS: We prospectively enrolled a convenience sample of patients in the emergency department and intensive care unit who required CVC placement. Correct positioning was considered if turbulent flow was visualized in the right atrium on sub-xiphoid, parasternal or apical cardiac ultrasound after injecting 5 cc of sterile, non-agitated, normal saline through the CVC. RESULTS: Seventy-eight patients were enrolled. POCUS had a sensitivity of 86.8% (95%CI 77.1%–93.5%) and specificity of 100% (95%CI 15.8%–100.0%) for identifying correct central venous catheter placement. Median POCUS and CXR completion were 16 minutes (IQR 10–29) and 32 minutes (IQR 19–45), respectively. CONCLUSION: Ultrasound may be an effective tool to confirm central venous catheter placement in instances where there is a delay in obtaining a confirmatory CXR.

Role of Ultrasound in the Identification of Longitudinal Axis in Soft-Tissue Foreign Body Extraction.

Identification and retrieval of soft-tissue foreign bodies (STFB) poses significant challenges in the emergency department. Prior studies have demonstrated the utility of ultrasound (US) in identification and retrieval of STFBs, including radiolucent objects such as wood. We present a case of STFB extraction that uses US to identify the longitudinal axis of the object. With the longitudinal axis identified, the foreign body can be excised by making an incision where the foreign body is closest to the skin. The importance of this technique as it pertains to minimizing surrounding tissue destruction and discomfort for patients has not been previously reported.

Point-of-care ultrasound versus radiology department pelvic ultrasound on emergency department length of stay.

BACKGROUND: The study aimed to compare the time to overall length of stay (LOS) for patients who underwent point-of-care ultrasound (POCUS) versus radiology department ultrasound (RDUS). METHODS: This was a prospective study on a convenience sample of patients who required pelvic ultrasound imaging as part of their emergency department (ED) assessment. RESULTS: We enrolled a total of 194 patients who were on average 32 years-old. Ninety-eight (51%) patients were pregnant (<20 weeks). Time to completion of RDUS was 66 minutes longer than POCUS (95%CI 60-73, P<0.01). Patients randomized to the RDUS arm experienced a 120 minute longer ED length of stay (LOS) (95%CI 66-173, P<0.01). CONCLUSION: In patients who require pelvic ultrasound as part of their diagnostic evaluation, POCUS resulted in a significant decrease in time to ultrasound and ED LOS.

Pilot Study to Determine Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation by Novice Sonographers.

INTRODUCTION: The goal of this study was to investigate the efficacy of diagnosing shoulder dislocation using a single-view, posterior approach point-of-care ultrasound (POCUS) performed by undergraduate research students, and to establish the range of measured distance that discriminates dislocated shoulder from normal. METHODS: We enrolled a prospective, convenience sample of adult patients presenting to the emergency department with acute shoulder pain following injury. Patients underwent ultrasonographic evaluation of possible shoulder dislocation comprising a single transverse view of the posterior shoulder and assessment of the relative positioning of the glenoid fossa and the humeral head. The sonographic measurement of the distance between these two anatomic structures was termed the Glenohumeral Separation Distance (GhSD). A positive GhSD represented a posterior position of the glenoid rim relative to the humeral head and a negative GhSD value represented an anterior position of the glenoid rim relative to the humeral head. We compared ultrasound (US) findings to conventional radiography to determine the optimum GhSD cutoff for the diagnosis of shoulder dislocation. Sensitivity, specificity, positive predictive value, and negative predictive value of the derived US method were calculated. RESULTS: A total of 84 patients were enrolled and 19 (22.6%) demonstrated shoulder dislocation on conventional radiography, all of which were anterior. All confirmed dislocations had a negative measurement of the GhSD, while all patients with normal anatomic position had GhSD>0. This value represents an optimum GhSD cutoff of 0 for the diagnosis of (anterior) shoulder dislocation. This method demonstrated a sensitivity of 100% (95% CI [82.4-100]), specificity of 100% (95% CI [94.5-100]), positive predictive value of 100% (95% CI [82.4-100]), and negative predictive value of 100% (95% CI [94.5-100]). CONCLUSION: Our study suggests that a single, posterior-approach POCUS can diagnose anterior shoulder dislocation, and that this method can be employed by novice ultrasonographers, such as non-medical trainees, after a brief educational session. Further validation studies are necessary to confirm these findings.