To the Editor
We read with great interest the article by Huang et al,1 which describes the application of thoracic epidural block for the postoperative paralytic ileus. In the Introduction, there was an error in the sentence, “…sympathetic blockers cause decreased splanchnic hypoperfusion….” As the abstract of Reference 4 depicted,2 thoracic epidural analgesia “induced an increase in GMBF (gastric mucosal blood flow) compared with baseline and the control group.”
Although Huang et al,1 using the low thoracic epidural block, which dramatically decreased daily drainage from the nasogastric tube, there were complaints of numbness of the lower limbs and urinary incontinence. Because the celiac ganglia, which are located in front of the T12 and L1 vertebral bodies, are innervated by the branches of the sixth to the 11th ganglia of the thoracic cord, the ideal tip of the epidural catheter for the effect of celiac plexus blockade might be better around the midpoint between the T6 and T11 spinal cord.3 If the tip of the epidural catheter was anchored around the T8–T9 spinal cord rather than the T11, the infusion rate of the epidural block might be less and there might have been no cause for complaints.
The hypotension during thoracic epidural block most often occurs as a result of hypovolemia. Patients who are euvolemic will not become hypotensive. Hypotension resulting from sympathectomy and a loss of vascular tone will be pronounced in hypovolemic patients. We should not reduce the rate or concentration of the epidural infusion to overcome the hypotension during thoracic epidural block. The correct method way would be to correct hypovolemia, especially in patients with a nasogastric tube for decompression.
In order to hasten the resolution of postoperative ileus, we totally agree with the administration of local anesthetics into the thoracic epidural space to block the inhibitory spinal reflexes by Huang et al.1 We also advocate that the location of the epidural catheter is important for the blockade.