Phrenic nerve stimulation (PNS) to elicit diaphragm contraction was first described over 200 years ago in the management of a case of neonatal asphyxia [1]. Since then the technique has developed significantly with established therapeutic indications for patients with high cervical cord injury or central sleep apnoea syndromes. Temporary PNS may offer potential physiological benefits for multiple organ systems and may prevent or treat diaphragm weakness in critically ill patients (Fig. 1). PNS can be delivered by multiple routes including direct surgical implantation of electrodes[2], or via transvenous[3], percutaneous[4] or transcutaneous[5] routes.