In Reply

摘要

I thank Drs. Edsail, Dr. Lambert, and Drs. Moen, Dahl-gren, and Irestedt for their interest on this controversial topic, and for their insightful comments and questions. Their remarks clearly show the hurdles to overcome in developing evidence-based guidelines for strict aseptic technique during neuraxial instrumentation in anesthesia practice. Dr. Edsail raises a question that is often debated and quite controversial: Is the loss of resistance to saline superior to that to air? Although many complications, including pneumocephalus, nerve root compression, subcutaneous emphysema, venous air embolism, incomplete analgesia, and paresthesias, have been attributed to the loss of resistance to air, there is no mention in the anesthesia literature regarding air as a source of contamination in the epidural space. I would argue that there is a significantly higher chance of contamination from the large volume of air over the tray than the small amount injected with the syringe. The only way to prevent the epidural tray from being exposed to air is to do the procedure in a vacuum. Furthermore, epidural abscess has only been demonstrated to occur as a result of skin bacteria passing through a needle track, contaminated syringes, or local anesthetics, or hematogenous spread from another source.