Application of Tele-Ultrasound in Emergency Medical Services

Prehospital Ultrasound: A Narrative Review

Background: Point-of-care ultrasound is rapidly becoming more prevalent in the prehospital environment. Though considered a relatively new intervention in this setting, there is growing literature that aims to explore the use of prehospital ultrasound by EMS personnel.Methods: To better understand and report the state of the science on prehospital ultrasound, we conducted a narrative review of the literature.Results: Following a keyword search of MEDLINE in Ovid from inception to August 2, 2022, 2,564 records were identified and screened. Based on review of abstracts and full texts, with addition of seven articles via bibliography review, 193 records were included. Many included studies detail usage in air medical and other critical care transport environments. Clinicians performing prehospital ultrasound are often physicians or other advanced practice personnel who have previous ultrasound experience, which facilitates implementation in the prehospital setting. Emerging literature details training programs for prehospital personnel who are novices to ultrasound, and implementation for some study types appears feasible without prior experience. Unique use scenarios that show promise include during critical care transport, for triage in austere settings, and for thoracic evaluation of patients at risk of life-threatening pathology.Conclusion: There is a growing mostly observational body of literature describing the use of ultrasound by prehospital personnel. Prehospital ultrasound has demonstrated feasibility for specific conditions, yet interventional studies evaluating benefit to patient outcomes are absent.

Demonstration experiment of telemedicine using ultrasonography and telerehabilitation with 5G communication system in aging and depopulated mountainous area

Objective

The challenges of an aging population worldwide are the increased number of people needing medical and nursing care and inadequate medical resources. Information and communication technologies have progressed remarkably, leading to innovations in various areas. 5G communication systems are capable of high-capacity, high-speed communication with low latency and are expected to transform medicine. We aimed to report a demonstration experiment of telerehabilitation and telemedicine using a mobile ultrasound system in a depopulated area in a mountainous terrain, where 32% of the population are 65 years or older.

Methods

At the core hospital, a physician or physical therapist remotely performed ultrasonography or rehabilitation on a subject in a clinic. Five general residents participated in the telerehabilitation as subjects. The delay time and video quality transmitted with 5G and long-term evolution (LTE) communication systems were compared. The physician or physical therapist subjectively evaluated the quality and delay of the transmitted images and subject acceptability.

Results

Of seven physical therapists, six and three responded that the video quality was "good" for telerehabilitation with 5G/4K resolution and LTE, respectively. Five physical therapists and one physical therapist reported that the delay time was "acceptable" with 5G/4K resolution and LTE, respectively. For telemedicine using a mobile ultrasound system, the responses for 5G were "the delay was acceptable" and "rather acceptable." In contrast, both respondents' responses for LTE were "not acceptable."

Conclusions

Multiple high-definition images can be transmitted with lower latency in telerehabilitation and telemedicine using mobile ultrasound imaging systems with a 5G communication system. These differences affected the subjective evaluation of the doctors and physical therapists.

Tele-ultrasound in the Era of COVID-19: A Practical Guide

Telemedicine has evolved over the past 50 years, with video consultations and telehealth (TH) mobile apps that are now widely used to support care in the management of chronic conditions, but are infrequently used in acute conditions such as emergencies. In the wake of the COVID-19 pandemic, demand is growing for video consultations as they minimize health provider-patient interactions and thereby the risk of infection. Advanced applications such as tele-ultrasound (TUS) have not yet gained a foothold despite their achieving technical maturity and the availability of software from numerous companies for TUS for their respective portable ultrasound devices. However, ultrasound is indispensable for triage in emergencies and also offers distinct advantages in the diagnosis of COVID-19 pneumonia for certain patient populations such as pregnant women, children and immobilized patients. Additionally, recent work suggests lung ultrasound can accurately risk stratify patients for likely infection when immediate polymerase chain reaction (PCR) testing is not available and has prognostic utility for positive patients with respect to the need for admission and intensive care unit (ICU) treatment. Though currently underutilized, a wider implementation of TUS in TH applications and processes may be an important stepping-stone for telemedicine. The addition of ultrasound to TH may allow it to cross the barrier from being an application used mainly for primary care and chronic conditions to an indispensable tool used in emergency care, disaster situations, remote areas and low-income countries where it is difficult to obtain high-quality diagnostic imaging. The objective of this review was to provide an overview of the current state of telemedicine, insights into current and future use scenarios, its practical application as well as current TUS uses and their potential value with an overview of currently available portable and handheld ultrasound devices. In the wake of the COVID-19 pandemic we point out an unmet need and use case of TUS as a supportive tool for health care providers and organizations in the management of affected patients.

Remote real-time supervision of prehospital point-of-care ultrasound: a feasibility study

Background

Although prehospital point-of-care ultrasound (POCUS) is gaining in importance, its rapid interpretation remains challenging in prehospital emergency situations. The technical development of remote real-time supervision potentially offers the possibility to support emergency medicine providers during prehospital emergency ultrasound. The aim of this study was to assess the feasibility of live data transmission and supervision of prehospital POCUS in an urban environment and so to improve patients’ safety.

Methods

Emergency doctors with moderate ultrasound experience performed prehospital POCUS in emergency cases (n = 24) such as trauma, acute dyspnea or cardiac shock using the portable ultrasound device Lumify™. The ultrasound examination was remotely transmitted to an emergency ultrasound expert in the clinic for real-time supervision via a secure video and audio connection. Technical feasibility as well as quality of communication and live stream were analysed.

Results

Prehospital POCUS with remote real-time supervision was successfully performed in 17 patients (71%). In 3 cases, the expert was not available on time and in 1 case remote data transmission was not possible due to connection problems. In 3 cases tele-supervision was restricted to video only and no verbal communication was possible via the device itself due to power saving mode of the tablet.

Conclusion

Remote real-time supervision of prehospital POCUS in an urban environment is feasible most of the time with excellent image and communication quality.

Trial registration: ClinicalTrials Number NCT04612816.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00985-0.

5G enabled emergency telemedicine application mobile ultrasound: Development and Usability Study (Preprint)

Background

Digitalization affects almost every aspect of modern daily life, including a growing number of health care services along with telemedicine applications. Fifth-generation (5G) mobile communication technology has the potential to meet the requirements for this digitalized future with high bandwidths (10 GB/s), low latency (<1 ms), and high quality of service, enabling wireless real-time data transmission in telemedical emergency health care applications.

Objective

The aim of this study is the development and clinical evaluation of a 5G usability test framework enabling preclinical diagnostics with mobile ultrasound using 5G network technology.

Methods

A bidirectional audio-video data transmission between the ambulance car and hospital was established, combining both 5G-radio and -core network parts. Besides technical performance evaluations, a medical assessment of transferred ultrasound image quality and transmission latency was examined.

Results

Telemedical and clinical application properties of the ultrasound probe were rated 1 (very good) to 2 (good; on a 6 -point Likert scale rated by 20 survey participants). The 5G field test revealed an average end-to-end round trip latency of 10 milliseconds. The measured average throughput for the ultrasound image traffic was 4 Mbps and for the video stream 12 Mbps. Traffic saturation revealed a lower video quality and a slower video stream. Without core slicing, the throughput for the video application was reduced to 8 Mbps. The deployment of core network slicing facilitated quality and latency recovery.

Conclusions

Bidirectional data transmission between ambulance car and remote hospital site was successfully established through the 5G network, facilitating sending/receiving data and measurements from both applications (ultrasound unit and video streaming). Core slicing was implemented for a better user experience. Clinical evaluation of the telemedical transmission and applicability of the ultrasound probe was consistently positive.

Ultrasound in Telemedicine: A Brief Overview

The delivery of healthcare from a distance, also known as telemedicine, has evolved over the past 50 years, changing the way healthcare is delivered globally. Its integration into numerous domains has permitted high-quality care that transcends the obstacles of geographic distance, lack of access to health care providers, and cost. Ultrasound is an effective diagnostic tool and its application within telemedicine has advanced substantially in recent years, particularly in high-income settings and low-resource areas. The literature in Pubmed from 1960–2020 was assessed with the keywords “ultrasound”, “telemedicine”, “ultrasound remote”, and “tele-ultrasound” to conduct a SWOT analysis (strengths, weaknesses, opportunities, and threats). In addressing strengths and opportunities, we emphasized practical aspects, such as the usefulness of tele-ultrasound and the cost efficiency of it. Furthermore, aspects of medical education in tele-ultrasound were considered. When it came to weaknesses and threats, we focused on issues that may not be solved immediately, and that require careful consideration or further development, such as new software that is not yet available commercially.

Required Data Elements and Requirements of a Teleoncology System to Provide Treatment Plans for Patients with Breast Cancer

Background: Teleoncology refers to the use of telemedicine for remotely providing multiple specialized services in clinical oncology processes, including screening, diagnosis, treatment planning, consultation, supportive care, pathology, surgery, and follow-up services. Objectives: The aim of this study was to identify the required data elements and elicitation of requirements for developing a telemedicine system that aims at providing treatment plans for patients with breast cancer. Methods: In this study, the required data elements for the teleoncology system were identified through both the investigation of clinical guidelines and review of patients’ medical records. Identified data elements were determined by breast cancer specialists through the questionnaire. Besides, an interview method was applied to elicit the requirements of this system. Results: The identified data elements were categorized into 20 groups (e.g., clinical data, breast physical examinations, pathological results, tests, imaging results, etc.). From the 182 data elements included within the questionnaire, 125 were recognized to be necessary (n = 32, 100%). The lowest mean percentage were observed in magnesium blood test (Mg) (n = 21, 65.63%) and protein test (Pr) (n = 21, 65.63%). Other data elements with a minimum mean of 71.87% and a maximum mean of 100% were recognized necessary. In general, 2 major themes, 9 categories, and 45 related sub-categories were extracted from analyzing the findings of the interviews related to the system requirements. Conclusions: The findings of the present study can be used as a basis for developing teleoncology systems that aim at providing treatment plans for patients with breast cancer.

Development of Public Key Cryptographic Algorithm Using Matrix Pattern for Tele-Ultrasound Applications

A novel public key cryptographic algorithm using a matrix pattern is developed to improve encrypting strength. Compared to the Rivest–Sharmir–Adleman (RSA) and Elliptic Curve Cryptography (ECC) algorithms, our proposed algorithm has superior encrypting strength due to several unknown quantities and one additional sub-equation during the encrypting process. Our proposed algorithm also provides a faster encoding/decoding speed when the patient’s images for tele-ultrasound applications are transmitted/received, compared to the RSA and ECC encrypting algorithms, because it encodes/decodes the plain memory block by simple addition and multiplication operations of n terms. However, the RSA and ECC algorithms encode/decode each memory block using complex mathematical exponentiation and congruence. To implement encrypting algorithms for tele-ultrasound applications, a streaming server was constructed to transmit the images to the systems using ultrasound machines. Using the obtained ultrasound images from a breast phantom, we compared our developed algorithm, utilizing a matrix pattern, with the RSA and ECC algorithms. The elapsed average time for our proposed algorithm is much faster than that for the RSA and ECC algorithms.

Real-Time Tele-Mentored Low Cost "Point-of-Care US" in the Hands of Paediatricians in the Emergency Department: Diagnostic Accuracy Compared to Expert Radiologists

BACKGROUND

The use of point-of-care ultrasonography (POC US) in paediatrics is increasing. This study investigated the diagnostic accuracy of POC US in children accessing the emergency department (ED) when performed by paediatricians under the remote guidance of radiologists (TELE POC).

METHODS

Children aged 0 to 18 years accessing the ED of a third level research hospital with eight possible clinical scenarios and without emergency/severity signs at the triage underwent three subsequent US tests: by a paediatrician guided remotely by a radiologist (TELE POC); by the same radiologist (UNBLIND RAD); by an independent blinded radiologist (BLIND RAD). Tele-radiology was implemented using low cost "commercial off-the-shelf" (COTS) equipment and open-source software. Data were prospectively collected on predefined templates.

RESULTS

Fifty-two children were enrolled, for a total of 170 ultrasound findings. Sensitivity, specificity, positive and negative predictive values of TELE POC were: 93.8, 99.7, 96.8, 99.4 when compared to UNBLIND RAD and 88.2, 99.7, 96.8, 98.7 when compared to BLIND RAD. The inter-observers agreement between the paediatricians and either the unblind or blind radiologist was excellent (k = 0.93). The mean duration of TELE POC was 6.3 minutes (95% CI 4.1 to 8.5). Technical difficulties occurred in two (3.8%) cases. Quality of the transmission was rated as fair, good, very good and excellent in 7.7%, 15.4%, 42.3% and 34.6% of cases respectively, while in no case was it rated as poor.

CONCLUSIONS

POC US performed by paediatricians in ED guided via tele-radiology by an expert radiologist (TELE POC) produced reliable and timely diagnoses. Findings of this study, especially for the rarer conditions under evaluation, need further confirmation. Future research should investigate the overall benefits and the cost savings of using tele-ultrasound to perform US "at children's bedsides", under remote guidance of expert radiologists.

Point-of-Care Cardiac Ultrasound: Feasibility of Performance by Noncardiologists

Cardiac ultrasound has been used for decades to assess a wide variety of structural and functional pathology, as well as to monitor response to therapy. It offers the advantages of noninvasive, real-time dynamic functional assessment without the risk of radiation. Cardiologists have traditionally employed this modality and have established robust guidelines on the use of echocardiography. However, other specialties such as emergency medicine and critical care have realized the benefit of cardiac ultrasound and have established specialty guidelines in its use. There is growing evidence for the benefit of cardiac ultrasound at the point of care on hospital wards, clinics, and even pre-hospital environments as well. The pervasive use of focused ultrasound is perhaps most evident in the advent of ultrasound training in undergraduate medical curricula. This paper reviews some of the key literature on the use of focused, point-of-care ultrasound by noncardiologists. Feasibility, clinical utility, and emerging trends are reviewed.

Teleultrasound: historical perspective and clinical application

The health care of patients in rural or isolated areas is challenged by the scarcity of local resources, limited patient access to doctors and hospitals, and the lack of specialized professionals. This has led to a new concept in telemedicine: teleultrasonography (or teleultrasound), which permits ultrasonographic diagnoses to be performed remotely. Telemedicine and teleultrasonography are effective in providing diagnostic imaging services to these populations and reduce health care costs by decreasing the number and duration of hospitalizations and reducing unnecessary surgical procedures. This is a narrative review to present the potential clinical applications of teleultrasonography in clinical practice. The results indicate that although barriers persist for implementing teleultrasonography in a more universal and routine way, advances in telecommunications, Internet bandwidth, and the high resolution currently available for portable ultrasonography suggest teleultrasonography applications will continue to expand. Teleultrasound appears to be a valuable addition to remote medical care for isolated populations with limited access to tertiary healthcare facilities and also a useful tool for education and training.

Out of hospital point of care ultrasound: current use models and future directions

INTRODUCTION

Ultrasound has evolved from a modality that was once exclusively reserved to certain specialities of its current state, in which its portability and durability lend to its broadly increasing applications.

OBJECTIVES

This review describes portable ultrasound in the hospital setting and its comparison to gold standard imaging modalities. Also, this review summarizes current literature describing portable ultrasound use in prehospital, austere and remote environments, highlighting successes and barriers to use in these environments.

DISCUSSION

Prehospital ultrasound has the ability to increase diagnostic ability and allow for therapeutic intervention in the field. In austere environments, ultrasound may be the only available imaging modality and thus can guide diagnosis, therapeutics and determine which patients may need emergent transfer to a healthcare facility. The most cutting edge applications of portable ultrasound employ telemedicine to obtain and transmit ultrasound images. This technology and ability to transmit images via satellite and cellular transmission can allow for even novice users to obtain interpretable images in austere environments. Portable ultrasound uses have steadily grown and will continue to do so with the introduction of more portable and durable technologies. As applications continue to grow, certain technologic considerations and future directions are explored.

Help is in your pocket: the potential accuracy of smartphone- and laptop-based remotely guided resuscitative telesonography

BACKGROUND

Ultrasound (US) examination has many uses in resuscitation, but to use it to its full effectiveness typically requires a trained and proficient user. We sought to use information technology advances to remotely guide US-naive examiners (UNEs) using a portable battery-powered tele-US system mentored using either a smartphone or laptop computer.

MATERIALS AND METHODS

A cohort of UNEs (5 tactical emergency medicine technicians, 10 ski-patrollers, and 4 nurses) was guided to perform partial or complete Extended Focused Assessment with Sonography of Trauma (EFAST) examinations on both a healthy volunteer and on a US phantom, while being mentored by a remote examiner who viewed the US images over either an iPhone(®) (Apple, Cupertino, CA) or a laptop computer with an inlaid depiction of the US probe and the "patient," derived from a videocamera mounted on the UNE's head. Examinations were recorded as still images and over-read from a Web site by seven expert reviewers (ERs) (three surgeons, two emergentologists, and two radiologists). Examination goals were to identify lung sliding (LS) documented by color power Doppler (CPD) in the human and to identify intraperitoneal (IP) fluid in the phantom.

RESULTS

All UNEs were successfully mentored to easily and clearly identify both LS (19 determinations) and IP fluid (14 determinations), as assessed in real time by the remote mentor. ERs confirmed IP fluid in 95 of 98 determinations (97%), with 100% of ERs perceiving clinical utility for the abdominal Focused Assessment with Sonography of Trauma. Based on single still CPD images, 70% of ERs agreed on the presence or absence of LS. In 16 out of 19 cases, over 70% of the ERs felt the EFAST exam was clinically useful.

CONCLUSIONS

UNEs can confidently be guided to obtain critical findings using simple information technology resources, based on the receiving/transmitting device found in most trauma surgeons' pocket or briefcase. Global US mentoring requires only Internet connectivity and initiative.

Image quality in real-time teleultrasound of infant hip exam over low-bandwidth internet links: a transatlantic feasibility study

Evolution of communication systems, especially internet-based technologies, has probably affected Radiology more than any other medical specialty. Tremendous increase in internet bandwidth has enabled a true revolution in image transmission and easy remote viewing of the static images and real-time video stream. Previous reports of real-time telesonography, such as the ones developed for emergency situations and humanitarian work, rely on high compressions of images utilized by remote sonologist to guide and supervise the unexperienced examiner. We believe that remote sonology could be also utilized in teleultrasound exam of infant hip. We tested feasibility of a low-cost teleultrasound system for infant hip and performed data analysis on the transmitted and original images. Transmission of data was accomplished with Remote Ultrasound (RU), a software package specifically designed for teleultrasound transmission through limited internet bandwidth. While image analysis of image pairs revealed statistically significant loss of information, panel evaluation failed to recognize any clinical difference between the original saved and transmitted still images.

Evaluation of tele-ultrasound as a tool in remote diagnosis and clinical management at the Amundsen-Scott South Pole Station and the McMurdo Research Station

Abstract Background: A large number of Antarctic stations do not utilize ultrasound for medical care. Regular use of ultrasound imaging at South Pole and McMurdo Stations first began in October 2002. To date, there has been no evaluation of medical events requiring ultrasound examination from this remote environment. Additionally, the importance of tele-ultrasound for clinical management in Antarctica has not yet been assessed. We therefore conducted a retrospective analysis of all ultrasound exams performed at South Pole and McMurdo Stations between October 2002 and October 2003.

SUBJECTS AND METHODS

Radiology reports and patient charts were reviewed for pre- and post-ultrasound diagnosis and treatment.

RESULTS

Sixty-six ultrasound exams were conducted on 49 patients. Of the exams, 94.0% were interpreted by the store-and-forward method, whereas 6.0% were interpreted in "real-time" format. Abdominal, genitourinary, and gynecology ultrasound exams accounted for 63.6% of exams. Ultrasound examination prevented an intercontinental aeromedical evacuation in 25.8% of cases, and had a significant effect on the diagnosis and management of illness in patients at South Pole and McMurdo research stations.

CONCLUSIONS

These findings indicate that diagnostic ultrasound has significant benefits for medical care at Antarctic stations and that tele-ultrasound is a valuable addition to remote medical care for isolated populations with limited access to tertiary-healthcare facilities.

Development and evaluation of a novel, real time mobile telesonography system in management of patients with abdominal trauma: study protocol

BACKGROUND

Despite the use of e-FAST in management of patients with abdominal trauma, its utility in prehospital setting is not widely adopted. The goal of this study is to develop a novel portable telesonography (TS) system and evaluate the comparability of the quality of images obtained via this system among healthy volunteers who undergo e-FAST abdominal examination in a moving ambulance and at the ED. We hypothesize that: (1) real-time ultrasound images of acute trauma patients in the pre-hospital setting can be obtained and transmitted to the ED via the novel TS system; and (2) Ultrasound images transmitted to the hospital from the real-time TS system will be comparable in quality to those obtained in the ED.

METHODS

Study participants are three healthy volunteers (one each with normal, overweight and obese BMI category). The ultrasound images will be obtained by two ultrasound-trained physicians The TS is a portable sonogram (by Sonosite) interfaced with a portable broadcast unit (by Live-U). Two UTPs will conduct e-FAST examinations on healthy volunteers in moving ambulances and transmit the images via cellular network to the hospital server, where they are stored. Upon arrival in the ED, the same UTPs will obtain another set of images from the volunteers, which are then compared to those obtained in the moving ambulances by another set of blinded UTPs (evaluators) using a validated image quality scale, the Questionnaire for User Interaction Satisfaction (QUIS).

DISCUSSION

Findings from this study will provide needed data on the validity of the novel TS in transmitting live images from moving ambulances to images obtained in the ED thus providing opportunity to facilitate medical care of a patient located in a remote or austere setting.

Pocket mobile smartphone system for the point-of-care submandibular ultrasonography

BACKGROUND

Focused ultrasonography of the airway may be useful in the prediction of difficult intubation. The wider use of sonography in quantitative airway assessment may depend on the availability of highly portable, inexpensive, and accurate ultrasound systems. Pocket-sized ultrasound devices are emerging as a useful tool for point-of-care ultrasonography. The aim of this study was to evaluate the suprahyoid airway of healthy volunteers using a smartphone-based ultrasound imaging system in comparison with a platform-based machine.

METHODS

Mobisante MobiUS SP1 system with 2 mechanical sector (3.5 and 7.5 MHz) probes was used to acquire images of the tongue and measure the diameter of the hyomental muscle in the mouth floor. In the same group of subjects, imaging and measurements were repeated using BK Medical Flex Focus 400 ultrasound system with linear (18 MHz ) and curved 5 (MHz) transducers. The MobiUS system was also used to image plastic cylinders and procedure needles embedded in tofu bars. Outside diameters of cylinders were measured using digital calipers and sonography.

RESULTS

The mean diameter of the hyomental muscle in 10 healthy volunteers was 7.22 ± 1.6 mm using BK 18 MHz probe, 7.11 ± 1.7 mm using MobiUS 7.5 MHz probe, and 7.84 ± 2 mm using MobiUS 3.5 MHz probe. These means were not statistically different (BK vs Mo 7.5, P = .74, and BK vs Mo 3.5, P = .13). The mean outside diameter of plastic cylinders measured with digital calipers was 10.1 ± 0.2 mm (n = 5) vs 9.8 ± 0.3 mm and 10.2 ± 0.2 mm using 3.5 and 7.5 MHz probes, respectively. These means were not statistically different (calipers vs Mo 3.5, P = .16 and calipers vs Mo 7.5, P = .39).

CONCLUSION

Mobisante MobiUS system was able to acquire clinically useful images of the suprahyoid airway and muscular architecture in the mouth floor and allowed accurate measurements of linear distances.

Legal Bases for Medical Supervision via Mobile Telecommunications in Japan

This paper discusses the legal basis for mobile telecommunications-based medical supervision in Japan and bulletin from the Ministry of Health, Labour and Welfare. According to Article 44 of the Emergency Life-Saving Technician’s Act, an emergency technician shall not perform certain emergency medical procedures unless specifically authorized to do so by a medical practitioner. Actual conditions make these requirements unwieldy to put into practice. When requested to provide medical control in response to an ambulance call, a licensed physician has no choice but to allow the emergency technician to administer medical care. These circumstances expose medical practitioners to significant legal risks and societal ramifications. Is a mobile telecommunications environment characterized by insufficient information satisfactory for the medical care needed in ambulances? This paper discusses such medical care and its legal ramifications, including: how to implement such medical care under Article 21 of the Basic Act on Establishing a Networked Society Based on Advanced Information and Telecommunications. The Japanese government is obligated to provide citizens with broadband telecommunication lines in the near future to enable the smooth implementation of medical control over medical supervision provided in ambulances.

Wireless image streaming in mobile ultrasound

This work evaluates the feasibility of using 802.11 g ad hoc and 3G cellular broadband networks to wirelessly stream ultrasound video in real-time. Telemedicine ultrasound applications in events such as disaster relief and first-response triage can incorporate these technologies, enabling onsite medical personnel to receive assistance with diagnostic decisions by remote medical experts. The H.264 scalable video codec was used to encode echocardiographic video streams at various image resolutions (video graphics array [VGA] and quarter video graphics array [QVGA]) and frame rates (10, 15, 20, and 30 frames/s). The video stream was transmitted using 802.11 g and 3G cellular technologies, and pertinent transmission parameters such as data rate, packet loss, delay jitter, and latency were measured. 802.11 g permits high frame rate and VGA resolution and has low latency and jitter, but it is suitable only for short communication ranges, whereas the 3G cellular network allows medium to low frame rate streaming at QVGA image resolution with medium latency. However, video streaming can take place from any location with 3G service to any other site with Internet connectivity. The transmitted ultrasound video streams were subsequently recorded and evaluated by physicians with expertise in medical ultrasonography who evaluated the diagnostic value of the received video streams relative to the original videos. They expressed the opinion that image quality in the case of both 802.11 g and 3G was fully to adequately preserved, but missed frames could momentarily decrease the diagnostic value. This research demonstrates that 3G and 802.11 g wireless networks combined with efficient video compression make diagnostically valuable wireless streaming of ultrasound video feasible.

Tele-ultrasound and paramedics: real-time remote physician guidance of the Focused Assessment With Sonography for Trauma examination

OBJECTIVES

The aim of this study was to examine the capability of ultrasound-naïve paramedics to obtain interpretable Focused Assessment With Sonography for Trauma (FAST) images under the remote direction of emergency physicians (EPs).

METHODS

Paramedics without experience using ultrasound participated in a 20-minute lecture covering orientation to the ultrasound machine and the FAST examination. The paramedics subsequently performed FAST examinations on a model patient, whereas the EP remained in another room, out of visual contact. The EP communicated with the paramedic via radio, viewing video from the ultrasound machine on a monitor and directing the probe movements to obtain the views of the FAST examination. We examined the success rate, time to complete the examinations, and adequacy of images from the paramedics' first FAST examination.

RESULTS

Fifty-one paramedics performed their first FAST examinations and were able to successfully complete 100% of the views of the FAST. The median time from probe placement to examination completion was 262 seconds (interquartile range, 206-343 seconds). The median time to complete right upper quadrant (RUQ) versus left upper quadrant (LUQ) views was 39 and 50 seconds, respectively. The time to complete the LUQ scan took significantly longer than the RUQ (P < .01). Paramedics completed cardiac and pelvic view in a median time of 42 and 25 seconds, respectively.

CONCLUSIONS

The study demonstrated that paramedics with no prior ultrasound experience could obtain FAST images under remote guidance from experienced EPs in less than 5 minutes. Given rapidly evolving data transmission technology, this has applicability in battlefield, remote, and rural prehospital settings.

Pulseless electrical activity, focused abdominal sonography for trauma, and cardiac contractile activity as predictors of survival after trauma

BACKGROUND

Pulseless electrical activity (PEA) secondary to both blunt and penetrating trauma is associated with minimal survival. The pericardial view of the focused abdominal sonography for trauma (p-FAST) can differentiate between patients with and without organized cardiac activity and may assist in the decision to terminate ongoing resuscitation.

METHODS

A retrospective review was performed for all patients presenting to a level I trauma center from January 2006 through January/2009 who had PEA on arrival or developed PEA in the emergency department. Additional data abstracted included outcome, the p-FAST findings, and mechanism of injury. Recorded FAST examinations were reviewed by a blinded ultrasound trained physician.

RESULTS

During the study period 25 patients presented with PEA and three developed PEA during initial resuscitation. Contractile cardiac activity was present in nine patients with PEA on presentation and immediately after deterioration to PEA in the three patients developing PEA. Four patients had a penetrating mechanism and 24 were blunt. Two pericardial effusions were present on examination, both after blunt trauma. Three patients survived beyond the emergency department (89% early mortality). The survivors had presented in PEA with organized cardiac contractile activity on ultrasound and had tension pneumothorax, tension hemothorax, and hypovolemia treated. Two patients died in the operating room of uncontrolled hemorrhage and one patient died 6 days after admission because of closed head injury.

CONCLUSIONS

The presence of PEA at any time during initial resuscitation is a grave prognostic indicator. p-FAST is a useful test to identify contractile cardiac activity. p-FAST may identify those patients with potential for survival.