The diagnostic accuracy of a point-of-care ultrasound protocol for shock etiology: A systematic review and meta-analysis.

Objective: The aim of this study was to perform a systematic review and meta-analysis of the diagnostic accuracy of a point-of-care ultrasound exam for undifferentiated shock in patients presenting to the emergency department.
Methods: Ovid MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, and research meeting abstracts were searched from 1966 to June 2018 for relevant studies. QUADAS-2 was used to assess study quality, and meta-analysis was conducted to pool performance data of individual categories of shock.
Results: A total of 5,097 non-duplicated studies were identified, of which 58 underwent full-text review; 4 were included for analysis. Study quality by QUADAS-2 was considered overall a low risk of bias. Pooled positive likelihood ratio values ranged from 8.25 (95% CI 3.29 to 20.69) for hypovolemic shock to 40.54 (95% CI 12.06 to 136.28) for obstructive shock. Pooled negative likelihood ratio values ranged from 0.13 (95% CI 0.04 to 0.48) for obstructive shock to 0.32 (95% CI 0.16 to 0.62) for mixed-etiology shock.
Conclusion: The rapid ultrasound for shock and hypotension (RUSH) exam performs better when used to rule in causes of shock, rather than to definitively exclude specific etiologies. The negative likelihood ratios of the exam by subtype suggest that it most accurately rules out obstructive shock.