The presence of rib fractures in deceased infants is generally considered to be highly specific of non-accidental injury, with some pathologists considering them to be evidence of abuse. Although rib fractures may occur during resuscitative efforts in adults, the general consensus is that such injuries are exceptional in infants owing to inherent plasticity within the thoracic region. The recommendation for cardiopulmonary resuscitation (CPR) of infants since the year 2000 has been for the use of the “two-thumb” technique. However, there has been limited biomechanical investigation to what injuries may occur subsequent to this specific form of CPR. The overall aim of this thesis was to determine if two-thumb CPR can cause similar rib injuries to those seen in abusive squeezing cases. In particular, whether or not this CPR technique allows for over excessive levering of the posterior rib over the transverse process of the spine. To this end, physical experimentation simulating both two-thumb CPR and abusive squeezing was performed on an immature swine model of the infant thorax. The results of these tests did not show any significant difference in the force required to compress the thorax by one third its original anterior-posterior diameter in the two scenarios. One third being the recommended depth for CPR compressions. Fractures resultant from the testing were assessed with radiography and computed tomography, techniques commonly used by post-mortem pathologists. The type and nature of the injuries observed were remarkably similar in both scenarios. Rib injuries were primarily seen in the anterior part of the thoracic cage in both CPR and abusive specimens. The specific site of rib fracture was typically close to or within the costochondral joints. There was however an apparent absence of posterior rib fractures in the abusively tested cohort. This is in part due to the slight difference in profile of the neck and head areas within the ribs of the surrogate model. This acts to reduce the mechanical advantage offered by levering over the transverse processes of the spine. This study has shown anterior fractures of the ribs result from two-thumb CPR, challenging the long held belief that CPR cannot produce rib fractures. X-ray CT offered a significant improvement on the ability to detect costochondral junction injuries. This would offer further support to the routine use of X-ray CT in post-mortem examinations of infants where the cause of death is unknown. This has the potential to offer differential interpretation to the cause of rib injuries, especially in cases of sudden unexpected deaths in infancy, where otherwise child abuse may be diagnosed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:618005 |
| Date | January 2014 |
| Creators | Johnson, Mark Richard |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/an-investigation-of-immature-rib-fractures-resultant-from-both-cpr-and-abusive-scenarios(56eb58b0-76ff-4c5c-8720-52415b37945c).html |
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