Debra Morrison, MD, anesthesiologist at UCI gave a talk on anesthesia and robotic prostatectomy. While many of the points she reviewed have been covered elsewhere, there were a couple of suggestions that she had that I had not heard of before. She mentioned that with the extreme Trendelenburg position not only is the diaphragm pushed up into the chest but the trachea can be displaced towards the head. This can result in the ET tube migrating into the right mainstem bronchus and an abrupt increase in difficulty ventilating the patient. She is a pediatric anesthesiologist so perhaps she has seen this in that age group but I have not seen or heard of it happening in an adult. Still, it is worth keeping in mind in case you ever experience a sudden deterioration in the patient's status. The problem may be corrected by simply withdrawing the tube a cm or two until ventilation is returned to normal. At least try that before aborting the procedure and breaking everything down.