The effect of point-of-care ultrasound on family physicians’ diagnostic certainty and clinical decision making: a prospective cohort study from rural Canada

Early Abstract:

Introduction: By providing additional clinical information at the bedside, point of care ultrasound (PoCUS) has the potential to improve patient care, especially in rural settings where local consultative imaging and specialist services are limited or absent. PoCUS can safely facilitate de-escalation or escalation of care, which, in a rural context, can include a change in the decision to refer or transport out of town to a higher level of care. This study aimed to understand the utility of PoCUS for rural family physicians (FPs) by assessing how PoCUS affects their diagnostic certainty and clinical decision making.
Methods: Convenience sampling was used to recruit five FPs from different rural communities in British Columbia, Canada, a geographically large province that experiences inclement weather. FPs collected data on their PoCUS exams over two to ten weeks. They recorded their pre and post PoCUS diagnostic probabilities on a 0-100% scale, with 0% representing complete confidence that a patient does not have a working diagnosis and 100% complete confidence that a patient does. Each diagnostic probability was assigned to one of three diagnostic certainty categories according to the following scheme: 25-74% corresponds to low, 6-24% or 75-89% corresponds to intermediate, and ≤5% or ≥90% corresponds to high. FPs also recorded their patient care plans at pre and post PoCUS. Each plan was assigned to one of six levels of care, ranging from discharge without referral or follow-up to transport out of town to a higher-level facility. The Wilcoxon signed rank test for clustered data was used to assess the statistical significance of changes in diagnostic certainty and the planned level of patient care following PoCUS use. Scans were grouped/clustered by FP during analysis.
Results: Altogether, FPs collected data on 68 PoCUS exams. All nine PoCUS organ systems, as defined by BC PoCUS, were scanned. Overall, PoCUS led to an increase in diagnostic certainty and a shift to less specialized patient care plans. Diagnostic certainty increased in 68% of cases (p-value=0.01). The planned level of care for patients changed in 36% of cases (decreased in 32% and increased in 4%), but this change was not statistically significant (p-value=0.08). For 13 patients, there was a change in planned out-of-town transport to a higher level of care (high urgency) or referral to a specialist (low urgency). Overall, transport was removed for four patients and added for two other patients.  
Conclusion: Consistent with the few other studies from high-income countries on this topic, our findings indicate that PoCUS positively impacts patient care by usually increasing rural FPs’ diagnostic certainty, which can influence their clinical decision making. The most important PoCUS facilitated change observed was whether to transport out of town, which can result in major cost savings if appropriately avoided or greatly improve patient outcomes if the need for transport is recognized sooner. Our findings, if validated by larger studies, will likely help to drive PoCUS policy and practice decisions in Canada.
Keywords: Canada, clinical decision making, diagnostic certainty, family physician, patient management, point of care ultrasound, PoCUS.