Point-of-care ultrasound for FAST and AAA in rural New Zealand: quality and impact on patient care

Objective: Point-of-care ultrasound (POCUS) has the potential to improve access to diagnostic imaging for rural communities. This paper evaluates the sensitivity and specificity, impact on patient care, quality, and safety, of two common POCUS examinations, FAST (focused assessment with sonography in trauma) and AAA (aortic aneurysm), in the rural context.

Methods: This study is a subgroup analysis of a larger study into POCUS in rural NZ. Twenty-eight physicians in 6 New Zealand rural hospitals, with limited access to formal diagnostic imaging, completed a questionnaire before and after POCUS scans to assess the extent to which it altered diagnostic certainty and patient disposition (discharge vs. admit to rural hospital vs. transfer to urban hospital). The investigators and a specialist panel reviewed images for technical quality and accuracy of interpretation; and patient clinical records to determine accuracy of the POCUS findings and their impact on patient care.

Results: For FAST and AAA scans respectively:  Sensitivity 75% and 100%. Specificity 100% and 93%;  rural doctors correctly interpreted their POCUS images for 97% and 91% of scans; the proportion of scans that had either a ‘significant’ or ‘major’ impact on patient care was 17% and 31%; POCUS resulted in the disposition being deescalated for 15% and 10%, and escalated for 5% and 3%, of patients.

Conclusions: In the rural context POCUS AAA is a reliable ‘rule out’ test for ruptured abdominal aortic aneurysm and FAST scan has a role as a ‘rule in’ test for solid organ injury.   These findings are consistent with larger studies in the emergency medicine literature.