The Utilization of Handheld Ultrasound Devices in a Prehospital Setting

Diagnostic accuracy of prehospital lung ultrasound for acute decompensated heart failure: A systematic review and Meta-analysis

BACKGROUND

Lung ultrasound (LUS) reduces time to diagnosis and treatment of acute decompensated heart failure (ADHF) in emergency department (ED) patients with undifferentiated dyspnea. We conducted a systematic review to evaluate the diagnostic accuracy and clinical impact of LUS for ADHF in the prehospital setting.

METHODS

We performed a keyword search of multiple databases from inception through June 1, 2023. Included studies were those enrolling prehospital patients with undifferentiated dyspnea or suspected ADHF, and specifically diagnostic studies comparing prehospital LUS to a gold standard and intervention studies with a non-US comparator group. Title and abstract screening, full text review, risk of bias (ROB) assessments, and data extraction were performed by multiple authors. and adjudicated. The primary outcome was pooled sensitivity, specificity, and diagnostic likelihood ratios (LR) for prehospital LUS. A test-treatment threshold of 0.7 was applied based on prior ADHF literature in the ED. Intervention outcomes included mortality, mechanical ventilation, and time to HF specific treatment.

RESULTS

Eight diagnostic studies (n = 691) and two intervention studies (n = 70) met inclusion criteria. No diagnostic studies were low-ROB. Both intervention studies were critical-ROB, and not pooled. Pooled sensitivity and specificity of prehospital LUS for ADHF were 86.7% (95%CI:70.8%-94.6%) and 87.5% (78.2%-93.2%), respectively, with similar performance by physician vs. paramedic LUS and number of lung zones evaluated. Pooled LR+ and LR- were 7.27 (95% CI: 3.69-13.10) and 0.17 (95% CI: 0.06-0.34), respectively. Area under the summary receiver operating characteristic curve was 0.922. At the observed 42.4% ADHF prevalence (pre-test probability), positive pre-hospital LUS exceeded the 70% threshold to initiate treatment (post-test probability 84%, 80-88%).

CONCLUSIONS

LUS had similar diagnostic test characteristics for ADHF diagnosis in the prehospital setting as in the ED. A positive prehospital LUS may be sufficient to initiate early ADHF treatment based on published test-treatment thresholds. More studies are needed to determine the clinical impact of prehospital LUS.

The Performance Characteristics of Handheld, Non-Piezoelectric Point-of-Care Ultrasound (POCUS) in the Emergency Department

The use of handheld point-of-care ultrasound (HH-POCUS) platforms is rapidly increasing, but the diagnostic performance of HH-POCUS in the emergency department (ED) has not been well-studied. For a period of one year, only a HH-POCUS system that uses a non-piezoelectric array (Butterfly iQ+™) was available for clinical POCUS examinations in our ED. We performed a retrospective observational study of patients who underwent cardiac, thoracic, renal, biliary, or lower extremity venous (DVT) examinations from November 2021-November 2022 and calculated performance characteristics of HH-POCUS relative to radiology imaging. A total of 381 HH-POCUS studies were evaluated. Cardiac image quality was significantly lower than lung (p = 0.002). Over half of the studies (213/381) had imaging available for comparison, and HH-POCUS identified 86.5% (32/37, (95%CI) 70.4-94.9) of prespecified emergent diagnoses, including acute cholecystitis, severely reduced left ventricular ejection fraction, pericardial effusion or tamponade, moderate or larger pleural effusion, pneumothorax, moderate or larger hydronephrosis, and DVT. For less emergent diagnoses, 84.3% (43/51, (95%CI) 70.9-92.5) were identified. Overall, HH-POCUS using a non-piezoelectric array showed modest real-world performance in the ED for cardiac, thoracic, renal, biliary, and DVT examinations. HH-POCUS may be inadequate to rule out some common ED diagnoses, but had good specificity for certain conditions such as pericardial effusion.

Prehospital blood gas analyses in acute patients treated by a ground-based physician-manned emergency unit: a cohort study

BACKGROUND

The prehospital patients treated by ambulances and mobile emergency care units (MECU) are potentially critically ill or injured. Knowing the risks of serious outcomes in these patients is important for guiding their treatment. Some settings allow for prehospital arterial blood gas analyses. This study aimed to assess the outcomes of prehospital patients in relation to their prehospitally measured lactate, pH, and CO2 levels. The primary outcome was 7-day mortality.

METHODS

This register-based cohort study included patients with one or more prehospital blood gas analyses during their prehospital treatment by a physician-manned MECU, from January 2015 to December 2018. The blood samples were analyzed on an ABL90 Flex analyzer. Absolute values with percentages and odds ratios (OR) with 95% confidence intervals (CI) were calculated for the primary and secondary outcomes within prespecified subgroups.

RESULTS

The study included 745 patients, with an overall 7-day mortality rate of 20.0%.

LACTATE LEVEL

The 7-day mortality rates were 11.5% in patients with normal lactate levels (< 2.0 mmol/L), 14.4% with intermediate lactate levels (2.0-3.9 mmol/L), and 33.0% with high lactate levels (≥ 4.0 mmol/L). This corresponded to an OR of 1.30 (95% CI: 0.75-2.24) in the intermediate lactate group (2.0-3.9 mmol/L) and an OR of 3.77 (95% CI: 2.44-5.85) in the high lactate group (≥ 4.0 mmol/L), compared to the reference group with normal lactate.

PH LEVEL

The ORs of 7-day mortality rates were 4.82 (95% CI: 3.00-7.75) in patients with blood pH of < 7.35 and 1.33 (95% CI: 0.65-2.72) in patients with blood pH > 7.45, compared to the reference group with normal pH (7.35-7.45). CO2 LEVEL : The ORs of 7-day mortality rates were 2.54 (95% CI: 1.45-4.46) in patients with blood CO2 of < 4.3 kPa and 2.62 (95% CI: 1.70-4.03) in patients with blood CO2 > 6.0 kPa, compared to the reference group with normal CO2 (4.3-6.0 kPa).

CONCLUSIONS

This study found a strong correlation between increasing 7-day mortality rates and high blood lactate levels, low levels of pH, and abnormal CO2 blood levels, in prehospital patients undergoing prehospital blood analysis.

Impact of Smart Glasses on Patient Care Time in Emergency Medical Services Ambulance

INTRODUCTION

The smart glasses were implemented as an innovative communication tool to enhance effectiveness in the field. The traditional mode of communication for Emergency Medical Services (EMS) was radio, which had significant restrictions, primarily that they were unable to transmit any visual data. To enhance efficiency, the smart glasses were used for a more accurate assessment of the condition of patients during transportation. At this time, however, no prior study has shown significant benefits of employing smart glasses into EMS.

STUDY OBJECTIVE

The primary objective of this study is to compare the duration of patient care in an ambulance between the use and non-use of smart glasses. The secondary objective is to identify the characteristics of data communication between the ambulance and the hospital.

METHODS

This retrospective study utilized data gathered from closed-circuit television (CCTV) in ambulances at Srinagarind Hospital, Thailand. The data were collected over a six-month period, specifically from July through December 2021. The study included two groups: the smart glasses group and no smart glasses groups, both used during EMS operations. The primary data collected focused on the duration of patient care in the ambulance. Additionally, the type and characteristics of data transfers via smart glasses during EMS operations were also recorded.

RESULTS

Out of the 256 EMS operations included in this study, 53.1% (N = 68) of the participants in the smart glasses group were male. The majority of operations were performed during the afternoon shift in both groups. The average patient care time in the smart glasses group was 10.07 minutes, while it was 5.10 minutes in the no smart glasses group (P <.001), indicating a significant difference. Visual data communication between the ambulance and the hospital via smart glasses predominantly involved vital signs (100.0%), physical examination (56.3%), and neurological examination (42.2%). The use of audio data from the hospital to the ambulance primarily included taking additional patient history (26.6%) and performing physical examinations (19.5%).

CONCLUSION

The implementation of smart glasses in EMS operations resulted in an increase in patient care time in the ambulance. Furthermore, the use of smart glasses facilitated an effective channel of real-time two-way communication between the ambulance and the hospital.

Characteristics and Outcomes of Patient Transport to the Hospital by Emergency Medical Services (EMS); a Cross-sectional Study

Introduction

To enhance the efficiency, it is essential to understand the patterns of service users and develop policies that facilitate effective personnel and resource management. This study aimed to compare the characteristic and outcomes of patients who were transferred to emergency department (ED) by emergency medical services (EMS) and patients transported by other means.

Methods

This retrospective cross-sectional study was conducted at Srinagarind Hospital, Thailand, over a 5-year period from 2017-2021. The baseline characteristics, treatment modalities, and outcomes of patients who were transported to ED using EMS and Non-EMS were gathered and compared using STATA software.

Results

The study included 15,501 patients with the median age of 51 (interquartile range (IQR): 23-71) years who were referred by EMS over the five-year period (51.72% male). EMS patients had significantly higher median age (51 (23 - 71) vs. 37 (21 - 60); p < 0.001) with male preference (p < 0.001). In the EMS group, the triage level 1 (need for resuscitation) was higher than the non-EMS group (p < 0.001), most of the patients referred following trauma (p < 0.001), and the frequency of cardiac arrest was considerably higher than non-EMS group (2.54% vs 0.05%; p < 0.001). Patients in the EMS group received a higher number of blood tests (p < 0.001), plain radiographic exams (p < 0.001), computerized tomography (CT) scans (p < 0.001), and complex procedures (p < 0.001) than the non-EMS group. The EMS group had a greater number of hospital admissions (p < 0.001) and intensive care unit (ICU) admissions (p < 0.001) compared to the non-EMS group. The EMS group exhibited a significantly higher mortality rate compared to the non-EMS group (p < 0.001).

Conclusion

The population utilizing EMS services had higher median age, higher frequency of emergency cases and trauma related complaint, higher need for treatment interventions and imaging procedures, higher rate of hospital and ICU admissions, as well as higher rate of mortality compared to the non-EMS group.

The Impact of Prehospital Point of Care Ultrasounds on Emergency Patients Length of Stay in Thailand

Purpose

Globally, emergency departments (ED) are faced with an overcrowding problem. This issue is further compounded due to the multitude of contributing factors. Point of Care ultrasound (POCUS), especially when performed in prehospital care, that is before the patient is admitted to the ED has a high potential to reduce time of diagnosis and time of investigation which leads to shorter ED length of stay (LOS). The primary focus was on variances in ED LOS between the prehospital POCUS group and the standard care group.

Patients and Methods

A cross-sectional study was conducted on prehospital patients who were admitted to the ED at Srinagarind Hospital, Thailand, from January to December 2021. We divided patients into two groups including patients who obtained prehospital POCUS (the prehospital POCUS group) and patients who received standard care treatment in which there was no prehospital POCUS performed (the standard care group). POCUS and ED medical records were documented and submitted for analysis.

Results

Of 1348 prehospital patients, 840 were enrolled in this study: 169 with prehospital POCUS and 671 with standard care. Median LOS in the prehospital POCUS group was 159 min (IQR 89,289) versus 165 (IQR 102,330) in the standard care group (p = 0.125). Further imaging diagnostic test which affected ED LOS more than four hours was lower in the prehospital POCUS group (adjusted odds ratio [OR], 0.92; 95% confidence intervals [CI], 0.729-1.666) than in the standard care group. The factor associated with increased odds of ED LOS more than four hour in the prehospital POCUS group was admission to hospital (adjusted OR 1.88; 95% CI, 1.230-2.239).

Conclusion

Patients evaluated with prehospital POCUS had a shorter LOS than the only standard care treatment without statistical significance.

Optimizing Operation Time and Travel Distance for Motorcycle Ambulances in Emergency Medical Services

Introduction:

The motorcycle ambulance is used for quick access to patients. The response time to reach the patient takes less time than with a van ambulance. Moreover, accidents involving ambulances tend to be higher. However, at present, there is no study regarding the appropriate situation used of motorcycle ambulances in Emergency Medical Services (EMS) in Thailand.

Study Objective:

This study aims to optimize the travel distance and the operation time of motorcycle ambulances used.

Methods:

This study was a prospective, randomized controlled study at the EMS unit of Srinagarind Hospital, Thailand. The data collection period was from November 2021 through May 2022. All data involving dispatch of both ambulances in need were collected.

Results:

A total of 2,398 cases of EMS operation were examined. The mean age of the patients in the motorcycle ambulance group was 42.5 (SD = 6.5) years, and 51.3% (n = 616) were male. The response time for motorcycle ambulances and van ambulances during the operation time between 6:00am-9:00am was 6.2 minutes and 9.1 minutes, respectively. The response times for motorcycle ambulances and van ambulances regarding distance traveled from 0-5km were 4.2 minutes and 7.5 minutes, respectively (P <.001); distance traveled from 5-10km were 6.3 minutes and 8.2 minutes, respectively (P = .010).

Conclusion:

The motorcycle ambulance can reach patients faster than the ambulance at the operation time from 6:00am-9:00am and 3:00pm-6:00pm. This study focused on the distance less than 10 kilometers.

Handheld Ultrasound (HHUS): Potential for Home Palliative Care

Due to the severity of their disease, palliative care patients often present complex clinical symptoms and complaints like pain, shortness of breath, nausea, loss of appetite, and fatigue. Solely relying on the information available from the history and physical examination often causes uncertainty among palliative care physicians regarding treatment decisions during home visits, potentially leading to unnecessary hospitalizations or transfer to cross-sectional imaging in radiological practices. A rational approach is essential to avoid diagnostic aggressiveness while still providing the imaging information required for optimal palliative care. Bedside use of handheld ultrasound (HHUS) has the potential to expand the diagnostic and therapeutic spectrum in the case of symptom exacerbation but is still underutilized. In this review, we evaluate the potential uses of HHUS in home care settings to provide a more accurate diagnosis of the most common symptoms in palliative patients and to guide bedside interventions such as bladder catheterization, thoracentesis, paracentesis, venous access, and regional anesthesia. Specific training programs for ultrasound in palliative care are currently not available. Adequate documentation is warranted but fraught with technological and privacy issues. Expert supervision and quality assurance are necessary. Despite its limitation and challenges, we suggest that HHUS leads to improved clinical decision-making, expedited symptom relief, and reduced complications without burdening of the patient and costly transfer to hospital or specialty consultations.

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.

Prehospital Ultrasound Diagnosis of Massive Pulmonary Embolism by Non-Physicians: A Case Series

Massive pulmonary embolism (hemodynamically unstable, defined as systolic BP <90 mmHg) has significant morbidity and mortality. Point of care ultrasound (POCUS) has allowed clinicians to detect evidence of massive pulmonary embolism much earlier in the patient's clinical course, especially when patient instability precludes computerized tomography confirmation. POCUS detection of massive pulmonary embolism has traditionally been performed by physicians. This case series demonstrates four cases of massive pulmonary embolism diagnosed with POCUS performed by non-physician prehospital personnel.