Analgésie péridurale thoracique : anatomie, applications cliniques et perspectives

Approach of the epidural space is different at the thoracic level due to a more acute angle of spinous processes that varies from 25° to 45° from T4 to T10. Thoracic epidural volume is less important. Epidural pressure is more negative at the level of upper segments. Thoracic epidural space can be identified by the hanging drop technique or by loss of resistance to saline. The haemodynamic consequences of a thoracic block (bradycardia, hypotension, decrease of left ventricle inotropism) are mild when the extension of the block is limited; a more extended block related to lower thoracic segments injections may induce splanchnic block and venous blood sequestration. Thoracic epidural anaesthesia improves myocardial oxygen balance in patients with myocardial ischaemia. Local anaesthetic administration into the thoracic epidural space improves postoperative respiratory mechanical dysfunction and shortens the duration of postoperative ileus. Continuous administration of a local anaesthetic combined with a lipid soluble opioid guarantees a good quality analgesia.