The use of ultrasound in the out-of-hospital environment is increasingly feasible. The potential uses for point-of-care ultrasound (POCUS) by paramedics are many, but have historically been limited to traumatic indications. This study utilized a scoping review methodology to map the evidence for the use of POCUS by paramedics to assess respiratory distress and to gain a broader understanding of the topic.

Databases Ovid MEDLINE, EMBASE, CINAHL Plus, and PUBMED were searched from January 1, 1990 through April 14, 2021. Google Scholar was searched, and reference lists of relevant papers were examined to identify additional studies. Articles were included if they reported on out-of-hospital POCUS performed by non-physicians for non-traumatic respiratory distress.

A total of 591 unique articles were identified, of which seven articles met the inclusion criteria. The articles reported various different scan protocols and, with one exception, suffered from low enrolments and low participation. Most articles reported that non-physician-performed ultrasound was feasible. Articles reported moderate to high levels of agreement between paramedics and expert reviewers for scan interpretation in most studies.

Paramedics and emergency medical technicians (EMTs) have demonstrated the feasibility of lung ultrasound in the out-of-hospital environment. Further research should investigate the utility of standardized education and scanning protocols in paramedic-performed lung ultrasound for the differentiation of respiratory distress and the implications for patient outcomes.

Prehospital use of lung ultrasound (LUS) by paramedics to guide the diagnoses and treatment of patients has expanded over the past several years. However, almost all of this education has occurred in a classroom or hospital setting. No published prehospital use of LUS simulation software within an ambulance currently exists.

The objective of this study was to determine if various ambulance driving conditions (stationary, constant acceleration, serpentine, and start-stop) would impact paramedics’ abilities to perform LUS on a standardized patient (SP) using breath-holding to simulate lung pathology, or to perform LUS using ultrasound (US) simulation software. Primary endpoints included the participating paramedics’: (1) time to acquiring a satisfactory simulated LUS image; and (2) accuracy of image recognition and interpretation. Secondary endpoints for the breath-holding portion included: (1) the agreement between image interpretation by paramedic versus blinded expert reviewers; and (2) the quality of captured LUS image as determined by two blinded expert reviewers. Finally, a paramedic LUS training session was evaluated by comparing pre-test to post-test scores on a 25-item assessment requiring the recognition of a clinical interpretation of prerecorded LUS images.

Seventeen paramedics received a 45-minute LUS lecture. They then performed 25 LUS exams on both SPs and using simulation software, in each case looking for lung sliding, A and B lines, and seashore or barcode signs. Pre- and post-training, they completed a 25-question test consisting of still images and videos requiring pathology recognition and formulation of a clinical diagnosis. Sixteen paramedics performed the same exams in an ambulance during different driving conditions (stationary, constant acceleration, serpentines, and abrupt start-stops). Lung pathology was block randomized based on driving condition.

Paramedics demonstrated improved post-test scores compared to pre-test scores (P <.001). No significant difference existed across driving conditions for: time needed to obtain a simulated image; clinical interpretation of simulated LUS images; quality of saved images; or agreement of image interpretation between paramedics and blinded emergency physicians (EPs). Image acquisition time while parked was significantly greater than while the ambulance was driving in serpentines (Z = -2.898; P = .008). Technical challenges for both simulation techniques were noted.

Paramedics can correctly acquire and interpret simulated LUS images during different ambulance driving conditions. However, simulation techniques better adapted to this unique work environment are needed.

Dyspnea is a common presenting problem that creates a diagnostic challenge for physicians in the emergency department (ED). While the differential diagnosis is broad, acute decompensated heart failure (ADHF) is a frequent cause that can be challenging to differentiate from other etiologies. Recent studies have suggested a potential diagnostic role for emergency lung ultrasound (US). The objective of this systematic review was to assess the accuracy of early bedside lung US in patients presenting to the ED with dyspnea.

A systematic search of EMBASE, PubMed, and the Cochrane Library was performed in addition to a grey literature search. We selected prospective studies that reported on the sensitivity and specificity of B-lines from early lung ultrasound in dyspneic patients presenting to the ED. Selected studies underwent quality assessment using the Critical Appraisal and Skills Program (CASP) questionnaire.

The search yielded 3674 articles; seven studies met inclusion criteria and fulfilled CASP requirements for a total of 1861 patients. Summary statistics from the meta-analysis showed that as a diagnostic test for ADHF, bedside lung US had a pooled sensitivity of 82.5% (95% confidence interval [CI]=66.4% to 91.8%) and a pooled specificity of 83.6% (95% CI=72.4% to 90.8%).

Our results suggest that in patients presenting to the ED with undifferentiated dyspnea, B-lines from early bedside lung US may be reliably used as an adjunct to current diagnostic methods. The incorporation of lung US may lead to more appropriate and timely diagnosis of patients with undifferentiated ADHF.