Perspectives on Implementation of Point of Care Ultrasound in Prehospital Patient Care

doi:10.21203/rs.3.rs-4940433/v1

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Perspectives on Implementation of Point of Care Ultrasound in Prehospital Patient Care

https://doi.org/10.21203/rs.3.rs-4940433/v1

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Background:

Handheld point-of-care ultrasound (POCUS) devices offer potential benefits for enhancing patient care without causing delays in transporting patients to definitive care. This current study aims to assess the safety and effectiveness of POCUS used by paramedics in the prehospital setting alongside their standard assessment tools.

Methods:

This is a prospective longitudinal study from January 2022 and March of 2023. Eligible patients 18 years and older were categorized into two main groups: trauma or cardiac arrest. Trauma patients included those suspected of tension pneumothorax or intra-abdominal bleeding, while cardiac arrest patients were included regardless of etiology. Paramedics assessed and performed ultrasound exams based on their clinical judgment. Images were subsequently reviewed by an emergency physician trained in ultrasound interpretation, who evaluated the image quality and provided agreement or disagreement with the paramedics' interpretations.

Results:

In total, 92 patients were evaluated, and 41 patients with complete records were included for analysis. There are 24 cardiac arrest cases, which included 10 were noted to have cardiac activity on POCUS and the other 14 patients did not have cardiac activities on POCUS, and 17 were trauma. The agreement between paramedics’ interpretation and reviewing physicians’ interpretation ranged from 60% for those cardiac arrests with cardiac activities on POCUS, 78.6% for cardiac arrests without cardiac activities on POCUS, and 70.6% for trauma cases.

Conclusions:

These findings underscore the potential for paramedics, with appropriate training, to utilize ultrasound effectively in improving patient care for individuals suffering from traumatic injuries or in cardiac arrest.

Clinical trial number:

Not applicable. This is a prospective observational study. No intervention was applied to human subjects. This study was approved by the Institutional Review Board at Arrowhead Regional Medical Center (ARMC) with approval number 20-35.

emergency medicine

paramedics

prehospital

ultrasound

trauma

emergency cardiac care

Advances in technology present the opportunity for Emergency Medical Services (EMS) professionals to improve the quality of patient care.¹ Historically, most tools for assessing the patient’s condition in the prehospital setting have been based on the clinical impression obtained through the history of present illness and a focus physical examination.¹ In recent years, technology has evolved and presented opportunities for tools that were once restricted to the emergency department to make their way to the prehospital field of care.^2,3

One of the diagnostic modalities that has become a standard in the Emergency Departments (ED) and regional trauma centers is the point-of-care ultrasound (POCUS). A few examples of its utility include but are not limited to: Focused Assessment with Sonography for Trauma (FAST) exam, cardiac echo, soft tissue evaluations, central or peripheral venous cannulation, and arterial catheter placement. ^4–6 Many tools once restricted to the ED have become accessible to EMS personnel as they become portable and affordable. ⁷ It is therefore logical to evaluate the effectiveness and feasibility of using POCUS in real-world situations. ^6,8

A recent study found that 19% of needle decompressions performed by paramedics in prehospital settings were clinically inappropriate, and less than 28% of the needles successfully reached the thoracic cavity. ⁹ To decrease the failure rates of critical procedures in prehospital settings, an enhanced diagnostic capability would be beneficial. ¹⁰ Ultrasound can augment a paramedic’s diagnostic capabilities and potentially reduce the risk of iatrogenic complications.^11,12

In the last decade, the ultrasound device has evolved into a smaller, more portable, and less expensive technology.⁷ This evolution has prompted considerations within EMS systems where providers on scene can utilize POCUS findings to help determine destination to medical centers with the relevant specialties.¹³ This also presents the opportunity for on-scene personnel to provide life-saving interventions based on objective findings.^11,14

This study seeks to evaluate the safety and feasibility of portable ultrasound used by paramedics in the prehospital clinical environment to improve the quality of care in select critical care scenarios. It also seeks to evaluate the assessment skills, treatment options, and destination decisions made based on those skills without delaying patient care or transport.

This is a prospective observational study between January 2022 and March of 2023. This study included three fire departments located within the Southern California region consisting of Rialto, Redlands, and Corona Fire Departments. According to the latest census, the City of Rialto covers 22 square miles with a population of 103,545 residents; the City of Redlands is 36 square miles with a population of 73,849; the City of Corona is 40 square miles with a population of 159,46.^15–17 The Rialto Fire Department (FD) has an approximate annual volume of 7,400 medical responses; Redlands FD has an annual volume of 12,000; and Corona FD has an annual volume of 16,000.

One of the main receiving hospitals is Arrowhead Regional Medical Center (ARMC). ARMC is a 456-bed acute care teaching facility. It is an American College of Surgeons verified level I trauma center located in San Bernardino County (SBC), California. The ARMC emergency department (ED) is one of the busiest in the state of California with more than 100,000 visits and over 3000 adult trauma cases annually.⁹ This study was approved by the Institutional Review Board at Arrowhead Regional Medical Center (ARMC) with approval number 20–35.

All adult patients with suspected blunt abdominal/thoracic trauma and cardiac arrest were eligible for inclusion in the study. Prehospital Extended Focused Assessment with Sonography for Trauma (eFAST) was performed on scene or during transport by the paramedics. The primary focus was the detection of a tension pneumothorax or hemothorax, hemoperitoneum, pericardial effusion, and cardiac activity. The images recorded by portable ultrasound devices in this study were subsequently reviewed by two board-certified emergency medicine physicians, one of whom has completed an ultrasound fellowship.

Paramedics from participating fire departments underwent sessions of training focused on the theoretical and hands-on use of a modified eFAST in a two-hour course. Each training session included a pre-test, a PowerPoint presentation, a hands-on practical session, and a post-test evaluation. Instructors assessed participants on their image acquisition and skill competency. All instructors were either emergency medicine residents or attending physicians. The handheld ultrasound device was the iQ model handheld ultrasound manufactured by Butterfly Inc. This is a linear probe with operating frequency from 1 to 10 MHz with connection to an iPad tablet.

Paramedics received training on performing a POCUS evaluation within specific anatomical regions, including the right upper quadrant (RUQ), cardiac window (subxiphoid and parasternal), as well as assessment of anterior lung sliding. The RUQ was chosen as it offers the most sensitive view for finding free fluid in the abdomen.¹⁸ Participants were taught to identify the anatomic region between the liver and kidney (Morison’s pouch) to assess for the presence of free fluid. POCUS was used to view cardiac activity via the cardiac window to help guide additional treatment and transport decisions of patients in cardiac arrest. Bilateral lung sliding evaluations were to be used for patients who met the American College of Surgeons and regional EMS trauma criteria in patients with clinical suspicion of a tension pneumothorax. The left upper quadrant and suprapubic windows of the traditional FAST exam were excluded to simplify the initial training and to maximize skill retention.

During training, emphasis was placed on initially stabilizing patients at the trauma scene in accordance with Prehospital Trauma Life Support guidelines and local EMS agency protocol before incorporating ultrasound as an adjunct to patient evaluation. POCUS was used in cases of cardiac arrest with the goal of assessing cardiac activity during prehospital resuscitation efforts to assist with the decision to terminate resuscitation in accordance with established regional EMS protocols. The treating paramedics were required to complete a survey which collected information about their interpretation of the POCUS assessment. The surveys were linked to the images obtained and archived for physician reviews. The reviewing physicians indicated whether they agree with the interpretation made by the paramedics.

All statistical analyses were conducted using the SAS software for Windows version 9.4 (Cary, North Carolina, USA). Descriptive statistics were presented as means and standard deviations for continuous variables, along with frequencies and proportions for categorical variables. Independent t-test analyses were conducted to assess the difference in continuous variables between cardiac arrest and trauma. Crosstab Chi-square analyses were conducted to assess the association between categorical variables and nature of incident (cardiac arrest vs. trauma). All statistical analyses were two-sided. P-value < 0.05 was considered to be statistically significant.

In total, 92 patients were evaluated, and 41 were validated and able to be included for analysis within the framework of this study. Cases excluded from analysis were removed because of insufficient documentation, which limited the evaluator's ability to conduct the necessary assessment of both the quality of the images and the paramedic’s impressions. Figure 1 presented the detailed patient flow chart.

Among these 41 cases, 24 were cardiac arrests (10 were noted to have cardiac activity on POCUS and the other 14 patients did not have cardiac activities on POCUS), and 17 were trauma. The average age was 62.69 (standard deviation = 18.37) years and 65.9% (n = 27) were males. There was no statistically significant difference in gender among the three groups (57.1%, 60%, and 76.5% of participants being males for cardiac arrest with cardiac activities on POCUS, cardiac arrest without cardiac activities on POCUS, and trauma respectively, p = 0.4969, Table 1). However, patients in the cardiac arrest with cardiac activities on POCUS group were significantly older than the trauma group (average age 72.18 vs. 64.44 vs 54.67 for cardiac arrest with cardiac activities on POCUS, cardiac arrest without cardiac activities on POCUS, and trauma respectively, p = 0.0229). The agreement between paramedics’ interpretation and reviewing physicians’ interpretation ranged from 60% for those with cardiac activities on POCUS, 78.6% for those without cardiac activities on POCUS, and 70.6% for trauma cases.

Table 1

Comparison of variable among the three groups, which include cardiac arrest with cardiac arrest on POCUS, cardiac arrest without cardiac arrest on POCUS, and trauma group; POCUS = point-of-care ultrasound.
	Cardiac arrest with cardiac activities on POCUS (n = 14)	Cardiac arrest without cardiac activities on POCUS (n = 10)	Traumatic Injury (n = 17)	P-value
Gender				0.4969
Female	6 (42.9%)	4 (40%)	4 (23.5%)
Male	8 (57.1%)	6 (60%)	13 (76.5%)
Did you perform a FAST exam				N/A
Not applicable (not trauma)	14 (100%)	10 (100%)	0 (0%)
Yes	0 (0%)	0 (0%)	17 (100%)
Did you observe internal bleeding				N/A
No	0 (0%)	0 (0%)	16 (94.1%)
Not applicable (cardiac arrest)	14 (100%)	10 (100%)	0 (0%)
Yes	0 (0%)	0 (0%)	1 (5.9%)
Did you perform a lung scan				N/A
No	0 (0%)	0 (0%)	7 (41.2%)
Not applicable (cardiac arrest)	14 (100%)	10 (100%)	0 (0%)
Yes	0 (0%)	0 (0%)	10 (58.8%)
Did you observe a pneumothorax				N/A
No	0 (0%)	0 (0%)	16 (94.1%)
Not applicable (cardiac arrest)	14 (100%)	10 (100%)	0 (0%)
Yes	0 (0%)	0 (0%)	1 (5.9%)
Did you perform a needle decompression				N/A
No	0 (0%)	0 (0%)	16 (94.1%)
Not applicable (cardiac arrest)	14 (100%)	10 (100%)	0 (0%)
Yes	0 (0%)	0 (0%)	1 (5.9%)
In your review do you agree with the paramedic's interpretation				0.5606
Poor quality study	3 (21.4%)	4 (40%)	5 (29.4%)
Yes	11 (78.6%)	6 (60%)	12 (70.6%)
Age	72.18 ± 11.29	64.44 ± 12.13	54.67 ± 22.41	0.0479

Prior literature has reported that with approximately two hours of training, paramedics without any prior significant exposure to POCUS were able to produce an approximately 70% success rate in obtaining appropriate and adequate views utilizing the available POCUS devices.¹⁹ The current study findings support that paramedics can perform the modified eFAST exams in the selected conditions in the prehospital setting to improve patient care decisions.²⁰ The findings from this study also underscore the promising abilities of paramedics in retaining their ultrasound techniques.¹⁹

A prehospital POCUS program may be able to transmit ultrasound images from the field to receiving facilities via direct or a cloud-based application.⁷ This would facilitate online medical direction and provide feedback to EMS crews. Additionally, emergency medicine and trauma team members can better plan and allocate appropriate resources for each critical patient before arrival ⁷. Positive abdominal FAST findings in the prehospital setting may help EMS providers redirect patients to more appropriate treatment facilities such as trauma centers or trigger those facilities to begin preparing blood products ahead of time.^21–24 Improving communication between the prehospital and hospital team may help enhance the quality of care and resource allocation for each critical patient.

A major concern with POCUS utilization in the field is a possible increase in time between patient contact by the paramedics, inadvertently affecting the scene and transport times.^20,25 However, POCUS utilization in trauma is often done during patient transport rather than on scene. In cases of cardiac arrest, POCUS can help providers avoid unnecessary transport to the hospital if no cardiac activity was present.²¹ Though not specifically analyzed in the current study, subjective documentation by the prehospital providers indicated that it did not impact scene times significantly. This would be a critical area to analyze in future studies with an expectation of providers improving their scan times as proficiency increases.

In this study, investigators recruited emergency medicine residents and attending physicians at the local trauma center to provide the initial training on the specific device to be utilized in the field. The availability of local physicians to teach POCUS may be limited, medical sonographers may be used to augment the available personnel as trainers. Other obstacles include funding, training staff, allocated time to training, quality assessment and improvement, and medical director commitment. Agencies looking to adopt a prehospital POCUS program should develop their own training program and proficiency criteria.

The generalizability of our findings may be limited by several factors. Firstly, our study is a relatively small sample size study involving three fire departments in Southern California. Different geographic locations may have different experiences even if they implemented the same protocol as the current study. A larger scale prospective cohort study involving multiple geographic locations may be needed to confirm our findings. Secondly, more than half of the cases were excluded from the analysis due to missing documentation or network reliability issues. Any improvement on these two issues may help the study quality. Lastly, we tested the short-term ultrasound skills retention among paramedics, but we are unsure of the long-term retention of these newly acquired skills. It might be worthwhile to conduct a follow-up study to explore long-term ultrasound skills retention and how it can improve patient’s outcome in the pre-hospital field.

This study noted that paramedics can safely utilize ultrasound in the prehospital setting for trauma or cardiac arrest patients. However, there is still room for improvement on the proficiency of utilizing POCUS to obtain quality image. Frequent training, close oversight by the EMS medical directors, base hospitals and robust quality improvement programs needs to be in place to assure patient safety and the retention of the skills.

POCUS=Handheld point-of-care ultrasound; EMS=Emergency Medical Services; ED= Emergency Departments; FAST=Focused Assessment with Sonography for Trauma; FD=Fire Department; ARMC=Arrowhead Regional Medical Center; SBC=San Bernardino County; eFAST=Extended Focused Assessment with Sonography for Trauma; RUQ=right upper quadrant.

Ethical approval and Consent to participate:

Ethical approval to report this study was obtained from Arrowhead Regional Medical Center Institutional Review Board with the approval number 20-35. The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Written informed consent was waived from all participants and from a parent and/or legal guardian due to the emergency nature of the patient care. This study was also approved by the State of California Emergency Medical Authorities for the use of portable ultrasound in the field.

Consent for publication:

All authors have read and approved the final manuscript and consent to its publication.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

No funding was used to support this study.

Authorship contributions:

AT, DD, SM, RP: education, quality improvement, data collection, manuscript writing

RV, TP, BA, SP, FD, MMN: quality improvement, study design, manuscript writing and editing, data analysis.

Acknowledgements:

The authors would like to thank all of our collaborators, in particular Inland Counties Emergency Medical Authorities and the paramedics from Rialto Fire, Corona Fire, and Redlands Fire and their EMS coordinators (Kevin Deardon, Steven Wells, Carly Crews) for being instrumental in the training process, implementation, and data collection. We also want to acknowledge Dr. Deepak Chandwani and Dr. Louis Tran for implementation of the study protocol and editing the manuscript.

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No competing interests reported.

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You are reading this latest preprint version

Perspectives on Implementation of Point of Care Ultrasound in Prehospital Patient Care

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Abstract

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Background

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Discussion

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