Friday, July 4, 2014

Deliberate Hypotension. The Last Refuge Of A Weak Surgeon

For those who don't know, deliberate hypotension, as the name implies, means to drop a patient's blood pressure on purpose during an operation. The idea is that by lowering the BP, the patient will experience less blood loss and lessen the need for a transfusion. While there are a few scenarios that have a legitimate need for deliberate hypotension, such as a cerebral aneurysm clipping or a patient who is a Jehovah's Witness, I have found that most surgeons who request it usually are just not very good at their jobs.

I'll never forget the first few months after my residency when I was assigned to a particular ambulatory surgery center that our group covered. Many of the orthopedic procedures that were performed there were done by the biggest prick of a surgeon. His specialty was doing half assed arthroscopic operations on shoulders and knees, rarely taking more than fifteen minutes per case. His patients were rarely properly worked up preop. Many had multiple comorbidities like obesity, hypertension, and diabetes but I was lucky to get an ECG in the chart. Worst of all, this surgeon demanded that his patients' pressures be dropped to dangerously low levels.

This was particularly risky for his shoulder scopes. He wanted the patients positioned bolt upright, at ninety degrees. Even though there was hardly any history in the chart on the patient's cardiovascular status, he required systolic pressures down to the 90's. Eighties were even better. He had a tendency of constantly looking at the anesthesia monitor to make sure he was getting the blood pressure he needed. When he began shaving the bone and it started bleeding, he would inevitably scream at the anesthesiologist to drop the BP. During those cases I prayed that the patient was receiving adequate cerebral perfusion and would wake up at the end of the case.

His knee scopes were even more outrageous. Even though the patient had a tourniquet on the leg, once he started shaving the bone and cartilages and the patient bled, he would yell at the anesthesiologist to lower the BP. This despite the fact that the tourniquet was set at a much higher pressure than the patient's systolic pressure. Of course a regional anesthesia was out of the question for this guy since he didn't have time to let any anesthesiologist set up the necessary equipment to perform a proper block.

As a newly graduated anesthesiologist, I felt a strong obligation to comply with his demands no matter my misgivings. It got so bad that at one point I drew up syringes of nitroglycerin and gave tiny boluses of it to the patient right before the blood pressure cuff went up. Of course this played havoc with the patient's pressures and heart rate but at least every time he looked up the BP was in the proper range and I could keep my sanity for another day. Eventually I got sick of these games and asked my boss to move me somewhere else. He sighed and transferred me to a different facility, one of countless other colleagues in our group who have asked to never work at that place again. It was no problem really. He just put the next junior attending into that hellhole.

I didn't realize that what that surgeon requested was not only dangerous for the patient, it was also not necessary. That is until I worked with a different surgeon. Doing the same procedures, I reflexively lowered the patient's blood pressure. When he looked up, he asked me why the BP was so low. I replied that isn't that what surgeons like for arthroscopic cases? He said no. Just keep it near the patient's baseline pressure. BP's that low can be risky for patients. What? An orthopedic surgeon that actually thinks and cares about his patients? I then knew that some surgeons use deliberate hypotension to mask their incompetence.

It's not just arthroscopies that surgeons frequently request hypotension. Some spine surgeons I know always ask that the BP be lowered to prevent blood loss. This sounded reasonable on big spine cases until I started working with one spine surgeon who I highly respected. He told me to just keep the pressures near preop baseline and it shouldn't be a problem. As long as the BP doesn't shoot up to 180's/110's the patient will be fine. And you know what, he was right. His cases did not have any greater EBL's than the surgeons who wanted hypotension.

So now when a surgeon asks me for deliberate hypotension, I'm always extra alert to the possibility that he may not have the best surgical technique. Whether it is spine surgery or hip replacements, good surgeons can make their operations look effortless and remarkably free of blood loss. It is the bad surgeons who will be screaming at the anesthesiologist to drop the BP while the suction cannister fills up with heme.

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