Dr Burt has raised a valid point. I aim to place epidurals in the awake sitting patient, but sometimes circumstances dictate that the epidural can only be done in the anaesthetised patient. Due to the nature of the proposed surgery, patients are intubated and ventilated and placed in the lateral position. I use a loss of resistance to saline technique for identifying the epidural space in this situation as the epidural space pressure is likely to be positive. I have no experience of using the hanging drop technique in the spontaneously breathing, laterally positioned, anaesthetised patient and I am not aware of what the epidural pressure would be in this circumstance, although I would expect it to be negative.