US-CAB protocol for ultrasonographic evaluation during cardiopulmonary resuscitation: Validation and potential impact

Abstract

Background: We previously developed a US-CAB protocol for evaluation of circulatory-airway-breathing status during cardiopulmonary resuscitation (CPR). This study aimed at validating its application in real CPR scenarios and the potential impact on CPR outcomes.

Methods: The US-CAB protocol was implemented at the emergency department of National Taiwan University Hospital since January 2016. The US images, initiation time and operation duration of each US-CAB procedure, and relevant CPR information were recorded for analysis.

Results: From January 2016 to March 2017, 177 cardiac arrest patients receiving US-CAB were included. The durations of US-C-A-B procedure were 9.0 ± 1.4, 7.5 ± 1.5, and 16.0 ± 1.9 s, respectively. Cardiac activity was identified in 47 cases (26.6%), with higher rates of return of spontaneous circulation (ROSC) (95.7% vs. 21.5%, p < .0001) and survival to hospital discharge (25.5% vs. 10.0%, p < .01). Detection of cardiac activity after 10 min of CPR exhibited 100% sensitivity, specificity, positive and negative predictive value for ROSC. Cardiac tamponade was noted in eight patients. ROSC was achieved in two (25.0%) after pericardiocentesis, and aortic dissection was diagnosed in one (12.5%). Confirmation of correct intubation was significantly faster by US than by capnography (7.4 ± 1.4 vs. 38.3 ± 110.2 s, p < .001). US detected 21 (11.9%) esophageal intubations and 3 (1.7%) one-lung intubations. All were promptly corrected.

Conclusion: The US-CAB protocol is feasible in real CPR scenarios. It confers diagnostic value and prognostic implications which potentially impact the efficacy and outcomes of CPR. However, a future prospective multi-center study to validate its feasibility and indicate the need of structured training is mandated.

Keywords: Cardiac arrest; Cardiopulmonary resuscitation; Outcome; Ultrasound.