Rule of 4's: Safe and effective pleural decompression and chest drain insertion in severely injured children.

The intersecting scenarios of multi-trauma, thoracic injury and traumatic cardiac arrest present some of the most demanding moments in paediatric trauma. For these reasons, decision support through teamwork, checklists, technology and guidelines are central to ensuring quality paediatric trauma care. The 'Rule of 4's' is a simple aide-memoire, which guides clinicians of all grades, expertise and distractedness in a reliable approach to injured children who require safe and effective emergency pleural decompression and timely insertion of a chest drain. The Rule of 4's enables these important therapeutic goals to be met through: (i) four steps in a 'good plan'; (ii) fourth (or fifth) intercostal space as the basis for siting a 'good hole'; (iii) 4× uncuffed endotracheal tube size (4× [age/4 + 4]) to guide selection of a 'good tube'; and (iv) 4 cm mark for a 'good stop' to ensure the drain is in far enough but not too far.