Today you are scheduled to anesthetize a 28-year-old female to remove an ectopic pregnancy from the right fallopian tube. She is healthy, and you give her an ASA 1 classification. She weighs 72 kg and is 5 feet 10 inches tall. Routine general anesthesia is induced and maintained with 1–2% sevoflurane and 70% nitrous oxide in oxygen. Further, the surgeon places a transurethral bladder catheter and attaches it to a soft plastic collection bag.
Pneumoperitoneum is created with the insufflation of 100% carbon dioxide to a pressure of 16 mmHg. Fifteen minutes later, you notice that the urinary collection bag has become very distended. You diagnose a ruptured bladder and inform the surgeon. He is not happy and asks, “How do you know?” How can you quickly determine the type of gas responsible for this condition and thereby convince the surgeon? (Answer is posted in the comment section below!)…
