Causes of shock in the trauma patient

Question 20 from the second paper of 2011 asked about the causes of shock in trauma, what distinguishing features they have, and what echocardiographic features are associated with them. Question 2 from the second paper of 2017 instead presented the candidates with a hypotensive burns patient who was pulled out of a garage explosion. The causes of shock in trauma are numerous, and the attempt to go through them systematically has led me to a tabulated form of answer, which is found in this chapter.

Here is a table of the possible causes of shock in trauma, with their clinical and echocardiographic features.

Echocardiographic investigation of shock in trauma

A certain James Lai (FRCA, FANZCA) has published a brilliant set of slides for public delectation, which does this topic justice.

A 2011 study has also demonstrated that fluid assessment can be carried out quickly and effectively using IVC diameter and IVC respiratory variation, although in this study a surgical intensivist or an ultrasonographer (rather than an ED registrar) were performing the study. To address this concern, the same group later demonstrated that even a shaved ape could be trained to perform a limited goal-directed TTE.

Interestingly, there are also many studies of transoesophageal echo in trauma. One is tempted to salute the bravery of the man who would jam a TOE probe down into a trauma patient. However, it certainly seems to be helpful. A study comparing transthoracic and trasoesophageal assessment has demonstrated that TOE is significantly more accurate, and that TTE in severe chest trauma usually gives unsatisfactory images.