Increased Association of Liver Laceration with Subxiphoid Transthoracic Echocardiography During CPR in a Preclinical Swine Model
British Columbia Emergency Health Services, Vancouver, BC
Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK
Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC
Emergency Medicine, University of Saskatchewan, Saskatoon, SK
Introduction: Point of care ultrasound in cardiac arrest and cardiopulmonary resuscitation (CPR) can be used to identify reversable causes and has aided chest compression optimization in select cases. Both the subcostal and parasternal views can be used during pulse checks, though a subcostal approach may be more feasible during compressions. However, ongoing pressure from external probe placement has been hypothesized to increase risk of injury. We aimed to assess for the association between constant subxiphoid transthoracic echocardiography (TTEsub) during active CPR and liver laceration.
Methods: Injury data from female landrace swine (N=39, 35±2kg) who, following anesthetization, instrumentation, and stabilization, underwent CPR with (n=20) or without (n=19) TTEsub were analyzed retrospectively to investigate the effect of TTEsub during CPR and liver laceration. Chest compressions were performed in the conventional chest compression (CCC; centre of the chest, midline at the level of the aortic root) location and/or modified chest compression (MCC; intersection of the long & short axes of the left ventricle) location. Twenty swine received 12 minutes of CPR (n=10, CCC-only; n=10 MCC-only). Nineteen swine received 18 minutes of CPR (n=9, CCC-then-MCC; n=10, MCC-then-CCC). Liver lacerations were identified during post-mortem dissection. Fischer’s exact tests were used to assess for associations between liver injury and experimental condition. Significance was considered at P<0.05.
Results: No liver lacerations occurred during CCC-only or MCC-only CPR without TTEsub. There was no association between CCC-then-MCC or MCC-then-CCC CPR with TTEsub and liver laceration (11% [1/9] versus 30% [3/10]; P=0.58). There was an association between TTEsub and liver laceration (TTEsub 21% [4/19] versus no-TTEsub 0% [0/20]; P=0.04).
Conclusion: In the present study, we found an association between the use of TTEsub during CPR and liver laceration in a preclinical swine model. Irrespective of chest compression location (CCC-only versus MCC-only) or initial crossover location (CCC-MCC versus MCC-CCC), TTEsub was the only factor associated with liver laceration. TTEsub during CPR should be used cautiously, and these findings should be further explored in the clinical setting.