Choosing the right pressor at the time it's needed most by William Lee Thompson MD

I remember a case years ago in which I was the anesthesiologist for an Aortobifem bypass surgery. The patient was the usual vasculopath with a threatened limb, and surprisingly  had a normal appearing echo/electrocardiogram. The surgery was emergent and I warned the patient and his family that despite normal findings on ekg/echo, he was still very much at risk for intraoperative cardiovascular complications. Unfortunately, I was not in the postion to delay the surgery for a pharmacologic or exercise stress test. So the surgery proceeded.

That prophetic suspicion was realized 30 minutes after aortic cross clamp.  It was perplexing to me as to why it was not at the time of cross clamp, as that is the usual moment the heart experiences a sudden demand for oxygen as it pulsates against a more resistant aorta. The ekg and blood pressure suddenly changed, indicating all was not well.  At that time, the patient became extremely bradycardic and hypotensive. Obviously I wanted to decrease oxygen demand and increase oxygen supply, but I knew it was going to be challenging. We could not simply abort the case, as the surgeon was knee deep in the surgery. I was left with one option: Maintain perfusion at all costs with little options I had. How was I going to do that with the available drugs I had is the question. Which drug would best accomplish my goal?

As a board certified anesthesiologist, this scenario would be an excellent oral board exam question. Would you adminster a vasopressor, vasodilator, or both? Would you consult a colleague with experience in intraoperative transesophageal echo use and intrepretation? This is more a thought provoking question and not meant to guide you through a decision tree on managing the case. You are more than welcome to add your own thoughts regarding management if you like.

The patient was bradycardic with a heart rate in the low 30's and a systolic blood pressure around 40-50. EKG indicated st depression in several leads. He had an arterial line and central line placed at the start of the case.  How would you manage, and what pressor would be your drug of choice?