Prehospital delays are a major obstacle to timely reperfusion therapy in acute ischemic stroke. Stroke sign recognition, however, remains poor in the community. We present an analysis of repeated surveys to assess the impact of Face, Arm, Speech, Time (FAST) public awareness campaigns on stroke knowledge.

Four cross-sectional surveys were conducted between July 2016 and January 2019 in the province of Quebec, Canada (n = 2,451). Knowledge of FAST stroke signs (face drooping, arm weakness and speech difficulties) was assessed with open-ended questions. A bilingual English/French FAST public awareness campaign preceded survey waves 1–3 and two campaigns preceded wave 4. We used multivariable ordinal regression models weighted for age and sex to assess FAST stroke sign knowledge.

We observed an overall significant improvement of 26% in FAST stroke sign knowledge between survey waves 1 and 4 (odds ratio [OR] = 1.26; 95% CI: 1.02, 1.55; p = 0.035). After the last campaign, however, 30.5% (95% CI: 27.5, 33.6) of people were still unable to name a single FAST sign. Factors associated with worse performance were male sex (OR = 0.68; 95% CI: 0.53, 0.86; p = 0.002) and retirement (OR = 0.54; 95% CI: 0.35, 0.83; p = 0.005). People with lower household income and education had a tendency towards worse stroke sign knowledge and were significantly less aware of the FAST campaigns.

Knowledge of FAST stroke signs in the general population improved after multiple public awareness campaigns, although it remained low overall. Future FAST campaigns should especially target men, retired people and individuals with a lower socioeconomic status.

The Focused Assessment with Sonography in Trauma (FAST) exam is a rapid ultrasound test to identify evidence of hemorrhage within the abdomen. Few studies examine the accuracy of paramedic performed FAST examinations. The duration of an ultrasound training program remains controversial. This study's purpose was to assess the accuracy of paramedic FAST exam interpretation following a one hour didactic training session.

The interpretation of paramedic performed FAST exams was compared to the interpretation of physician performed FAST examinations on a mannequin model containing 300ml of free fluid following a one hour didactic training course. Results were compared using the Chi-square test. Differences in accuracy rate were deemed significant if p < 0.05.

Fourteen critical care flight paramedics and four emergency physicians were voluntarily recruited. The critical care paramedics were mostly ultrasound-naive whereas the emergency physicians all had ultrasound training. The correct interpretation of FAST scans was comparable between the two groups with accuracy of 85.6% and 87.5% (∆1.79 95%CI -33.85 to 21.82, p = 0.90) for paramedics and emergency physicians respectively.

This study determined that critical care paramedics were able to use ultrasound to detect free fluid on a simulated mannequin model and interpret the FAST exam with a similar accuracy as experienced emergency physicians following a one hour training course. This suggests the potential use of prehospital ultrasound to aid in the triage and transport decisions of trauma patients while limiting the financial and logistical burden of ultrasound training.

On-scene prehospital conditions and patient instability may warrant a during-transport ultrasound (US) exam. The objective of this study was to assess the effect of ambulance turbulence on the performance of the Focused Assessment with Sonography in Trauma (FAST) with a handheld US device.

This was a randomized controlled trial in which participants were randomized to perform a FAST in either a stationary or an in-motion military ambulance. Participants were physicians and physician assistants (PAs) with previous FAST training. All exams were performed on an US phantom model. The primary outcome was FAST completion time, reported as a mean, in seconds. Secondary outcomes included image acquisition score (range of 0-24, reported as a mean), diagnostic accuracy (reported as sensitivity and specificity), and a post-participation survey with five-item Likert-type scales.

Twenty-seven participants performed 27 FASTs, 14 in the stationary ambulance and 13 in the in-motion ambulance. All participants obtained the four requisite views of the FAST. A significant difference was detected in image acquisition scores in favor of the stationary ambulance group (19.4 versus 16.7 [95% CI for difference, 0.9-4.4]; P <.01). Significant differences in survey items between groups were related to obtaining and maintaining US images and the exam conditions. There was not a difference in FAST completion time between groups (98.5 seconds versus 78.7 seconds [95% CI for difference, -13.5 seconds to 53.1 seconds]; P = .23). Sensitivity and specificity of FAST in the stationary ambulance was 85.7% (95% CI, 67.3%-96.0%) and 96.4% (95% CI, 81.7%-99.9%) versus 96.2% (95% CI, 80.4%-99.9%) and 100.0% (95% CI, 86.8%-100.0%) in the in-motion ambulance group (P = .21).

Vehicular motion did not affect FAST completion time and diagnostic accuracy; however, it did reduce FAST image acquisition scores. The results suggest timely and diagnostically accurate FASTs may be completed by experienced sonographers during moderate levels of ambulance turbulence. Further investigation assessing the utility and limitations of newer handheld US devices in various prehospital conditions is warranted.

Prehospital ultrasound (PHUS) assessments by physicians and non-physicians are performed on medical and trauma patients with increasing frequency. Prehospital ultrasound has been shown to be of benefit by supporting interventions.

Which patients may benefit from PHUS has not been clearly identified.

A multi-variable logistic regression analysis was performed on a previously created retrospective dataset of five years of physician- and non-physician-performed ultrasound scans in a Canadian critical care Helicopter Emergency Medical Service (HEMS). For separate medical and trauma patient groups, the a-priori outcome assessed was patient characteristics associated with the outcome variable of “PHUS-supported intervention.”

Both models were assessed (Likelihood Ratio, Score, and Wald) as a good fit. For medical patients, the characteristics of heart rate (HR) and shock index (SI) were found to be most significant for an intervention being supported by PHUS. An extremely low HR was found to be the most significant (OR=15.86 [95% confidence interval (CI), 1.46-171.73]; P=.02). The higher the SI, the more likely that an intervention was supported by PHUS (SI 0.9 to<1.3: OR=9.15 [95% CI, 1.36-61.69]; P=.02; and SI 1.3+: OR=8.37 [95% CI, 0.69-101.66]; P=.09). For trauma patients, the characteristics of Prehospital Index (PHI) and SI were found to be most significant for PHUS support. The greatest effect was PHI, where increasing ORs were seen with increasing PHI (PHI 14-19: OR=13.36 [95% CI, 1.92-92.81]; P=.008; and PHI 20-24: OR=53.10 [95% CI, 4.83-583.86]; P=.001). Shock index was found to be similar, though, with lower impact and significance (SI 0.9 to<1.3: OR=9.11 [95% CI, 1.31-63.32]; P=.025; and SI 1.3+: OR=35.75 [95% CI, 2.51-509.81]; P=.008).

In a critical care HEMS, markers of higher patient acuity in both medical and trauma patients were associated with occurrences when an intervention was supported by PHUS. Prospective study with in-hospital follow-up is required to confirm these hypothesis-generating results.

O’DochartaighD, DoumaM, AlexiuC, RyanS, MacKenzieM. Utilization Criteria for Prehospital Ultrasound in a Canadian Critical Care Helicopter Emergency Medical Service: Determining Who Might Benefit. Prehosp Disaster Med. 2017;32(5):536–540.