Is point-of-care ultrasound a reliable predictor of outcome during traumatic cardiac arrest? A systematic review and meta-analysis from the SHoC investigators.

Aim: Point-of-care ultrasound (POCUS) has been shown to assist in predicting outcomes in cardiac arrest. We evaluated the test characteristics of POCUS in predicting poor outcomes: failure of return of spontaneous circulation (ROSC), survival to hospital admission (SHA), survival to hospital discharge (SHD) and neurologically intact survival to hospital discharge (NISHD) in adult and paediatric patients with blunt and penetrating traumatic cardiac arrest (TCA) in out-of-hospital or emergency department settings.

Methods: We conducted a systematic review and meta-analysis using the PRISMA guidelines. We searched Clinicaltrials.gov, CINAHL, Cochrane library, EMBASE, Medline and the World Health Organization-International Clinical Trials Registry from 1974 to November 9, 2020. Risk of bias was assessed using QUADAS-2 tool. We used a random-effects meta-analysis model with 95% confidence intervals with I statistics for heterogeneity.

Results: We included 8 studies involving 710 cases of TCA. For all blunt and penetrating TCA patients who failed to achieve ROSC, the specificity (proportion of patients with cardiac activity on POCUS who achieved ROSC) was 98% (95% CI 0.13 to 1.0). The sensitivity (proportion of patients with cardiac standstill on POCUS who failed to achieve ROSC) was 91% (95% CI 0.67 to 0.98). No patient with cardiac standstill survived. Substantial level of heterogeneity was noted.

Conclusions: Patients in TCA without cardiac activity on POCUS have a high likelihood of death and negligible chance of SHD. The numbers of patients included in published studies remains too low for practice recommendations for termination of resuscitation based solely upon the absence of cardiac activity on POCUS.