“You mean the screw isn’t supposed to be in the aorta?“: Massive bleeding during spine surgery

The case An other wise healthy 55-year-old woman with degenerative disc disease and chronic intractable low back pain presents for a seemingly straightforward level 3 posterior spinal fusion. You and your attending come up with a reasonable plan for her anesthetic, including general endotracheal anesthesia, maintained with a combination of intravenous and inhaled anesthetic; a second intravenous line; and standard American Society of Anesthesiology monitors. Things are going well, the line placement and flip to prone were flail-free, and the somatosensory evoked potential (SSEP) monitoring tech is happy with his signals. Hours pass uneventfully (with an expected amount of blood loss and fluid administration, given the case). Precipitously, your cuff pressure reads 70/30 (when it was 120/70), and strangely, you haven't heard any extra suctioning or the room go quiet. As you recheck it and open the fluids, you eyeball the suction canisters and peek your head over the curtain. Canisters are the same, and the surgeons don't look nervous. In fact, they are happy as they have finally finished the last screw, which was giving them problems. Your patient's pressure improves somewhat with fluid, so you turn off your remifentanil drip (they are starting to close) and chalk it up to underresuscitation. As surgery finishes up, your patient is weaned to nitrous and is breathing (with some pressure support) on her own, but her pressure is still low, considering that you have turned off the agent.