Ultrasonography should be used in the evaluation of the critically ill patient in cardiac arrest to establish the likely cause of arrest and prioritise life-saving treatments. In the hands of a skilled clinician, a haemo-peritoneum, a haemo or pneumothorax and cardiac tamponade can be reliably diagnosed within minutes. Appropriate interventions post diagnosis can then be established.
Cardiac tamponade is the underlying cause of approximately 10% of cardiac arrest in trauma. Penetrating injury to the chest or epigastric region is the most common cause of pericardial tamponade and treatment with immediate RT can be life-saving. Where the option to surgically manage the patient is not immediately available then pericardiocentesis can be attempted in the patient who is peri-arrest or in cardiac arrest with a high suspicion of tamponade until definitive care can be arranged. Needle aspiration of tamponade is unreliable, as the pericardium is usually full of clotted blood. However if immediate surgical option is not available then needle aspiration should be conducted under ultrasound guidance, where available.
The success of resuscitative thoracotomy (RT) is time critical. Penetrating trauma is more likely to respond to Resuscitative Thoracotomy than blunt trauma, where survival is poor. RT is unlikely to be successful if performed more than 10 minutes after the onset of cardiac arrest. A RT can:
Release tension pneumothorax and cardiac tamponade.
Allow direct control of intrathoracic haemorrhage.
Allow cross clamping of the descending aorta which will stop blood loss below the diaphragm, thereby improving brain and cardiac perfusion.
Permit open cardiac compression and defibrillation.
The decision to proceed with a RT will be based on the mechanism of injury, whether there is likely to be a surgically correctable problem and the duration since the onset of cardiac arrest. In order to give the patient the best chance of survival, the following needs to be in place prior to consideration of RT:
A highly skilled and trained team led by a competent medical practitioner who are operating under a robust governance framework.
Adequate equipment to carry out the procedure and deal with the findings.
Ideally RT should be carried out in an operating theatre environment but may be considered in other suitably resourced environments.
The time from loss of vital signs to commencing RT should be no longer than 10 minutes.
If any of the four criteria is not met, then RT should not be attempted.