Prehospital portable ultrasound for safe and accurate prehospital needle thoracostomy: a pilot educational study

A total of 30 EMS practitioners participated. Seven were female (23.3%). Twenty-five were certified at the Emergency Medical Technician Paramedic (EMT-P) level, and five were registered at the Prehospital Registered Nurse (PHRN) level. Mean years of ALS EMS experience was 15 years (range 0–44) (see Table 1).

The mean time to complete the simulated task using the landmark technique was shorter than that of the ultrasound technique at 10.7 s (range 3.35–45 s) vs. 19.9 s (range 7.850 s), respectively (p < 0.001). There was a lower proportion of correct placements for the landmark technique, 40/60 (66.7%), when compared to the ultrasound technique, 51/60 (85%) (p = 0.019) (see Table 2).

Critical anatomic structures were more frequently in the path of the needle with the landmark technique 9/60 (15%) when compared to the ultrasound technique 1/60 (1.7%) (p = 0.008). The most commonly encountered underlying structure was the liver in 6/120 total skill attempts (5%), followed by the heart or mediastinal structures in 3/120 skill attempts (2.5%) (see Table 2 and Fig. 1).

Following the educational intervention and ultrasound data collection station, participants were able to identify pneumothorax correctly on multimedia stimulus using ultrasound video clips and still images 94.7% of the time (range 70–100%).

This study was designed to be a pilot study. Thus, it was limited to one group of EMS professionals, which was heterogeneous with respect to their previous experience level and exposure to NT. NT is a low-frequency event in our rural EMS practice. Therefore, our findings do not necessarily translate to high-volume urban EMS agencies. Importantly, in a high-volume urban environment that may perform more needle decompressions, the number of paramedics may be higher, resulting in the same low-volume skill per paramedic regardless of the paramedic’s environment. This limit to generalizability is compounded when we factor in the differences in EMS system design between the North American model, predominately staffed by paramedical practitioners, and the European model, where staffing is predominately physician-based [20]. We note the potential for an educational effect given participants reviewed anatomy during the educational session, irrespective of its focus on ultrasound. This effect was not accounted for within our study design. Furthermore, our study took place with a small group of EMS professionals using one handheld ultrasound. There is significant variability between the handheld devices currently deployed in the field. Additionally, our ultrasound models were homogenous with respect to weight, and all had BMI < 35 kg/m². Finally, we were unable to include a control group that had received teaching on pneumothorax and proper placement of NT without an ultrasound component to delineate the effect of the educational intervention on the outcomes measured.

Our data demonstrate that a brief lecture followed by hands-on ultrasound training in an ultrasound-naive cohort of EMS providers was effective in allowing for rapid identification of appropriate needle thoracostomy position in the immediate post-education period during a simulated session in a non-clinical environment. It appeared feasible to deliver the training, and all participants were able to successfully complete the session as delivered. Ultrasound guidance resulted in fewer critical anatomic structures potentially injured by the procedure and required less than 10 s of additional time compared to the landmark technique.

Additionally, with the utilization of POCUS, there was less variation in the distance between the pleural space estimated and the actual distance that would need to be traversed to place a needle to reach the pleural space. The acquisition of the depth to the pleural space is hypothesized to allow for a higher rate of procedural success, given a location that is most appropriate for the available NT catheter would be chosen.

Similar to previous studies in other environments, non-ultrasound trained participants, the prehospital ALS providers in our example, quickly learned to apply ultrasound in the detection and diagnosis of pneumothorax in both cinematic and M-mode scenarios when tested with visual stimulus following the session.

These results add to the growing body of evidence that compact, handheld ultrasound devices can be utilized by prehospital personnel to potentially improve safety and effectiveness during high-risk, low-volume skills when compared to traditional techniques. These devices have been previously shown to be accurate in the acquisition of images compared to traditional non-handheld devices [21], which demonstrates the potential feasibility of implementing an EMS agency deploying such a device in the field to assist in procedures such as needle thoracostomy.

Future studies should focus on utilizing handheld ultrasound devices within a clinical setting, either in a prospective cohort or randomized control setting to determine if the use of such devices enhances safety and patient care in various EMS environments, including rural, suburban, urban, and helicopter settings. We would also encourage the expansion of the research setting to include both North American and European model EMS systems. This would build on the current study to allow for more generalizability from the non-clinical simulation environment seen here and the often austere environment encountered by prehospital paramedics and nurses when performing this skill in real-time. Further research would also benefit from a focus on the addition of comparison arms to validate the intervention, including in-service sessions on the treatment of tension pneumothorax with needle thoracostomy without ultrasound teaching or ultrasound devices. Additionally, our study was focused on process and disease-oriented outcomes. The addition of patient-oriented outcomes would help strengthen future studies.

In summary, within this cohort of rural North American EMS paramedics and nurses, a brief educational intervention involving teaching-focused thoracic ultrasound was feasible to deliver. Ultrasound guidance required an average of ten seconds longer, but increased safe and accurate simulated needle thoracostomy placement with fewer identified potential iatrogenic injuries. Further research is necessary to confirm these findings in a clinical setting. Our study adds to a growing body of evidence suggesting that prehospital ultrasound for needle thoracostomy may be safe and effective.