The replacement of Roy Nothnagel's defective heart valve had reached a key point; silence filled the operating room at Abbott Northwestern Hospital as Dr. Paul Sorajja and his team prepared to implant a new valve — and react if their patient faltered.

Then came the wisecrack. "God," a baritone voice said, "I feel like I'm in Houston and there's a rocket launch."

It was Nothnagel.

Until recently, patients in his place would have been unconscious by this point. But now, Abbott and other hospitals are keeping them awake as part of a broader effort to limit the use of general anesthesia due to growing evidence that it can hinder a patient's recovery and leave long-term effects on the body.

Research also suggests that minimal, or conscious, sedation during valve implants improves outcomes and shortens hospital stays. And, occasionally, it generates comic relief in the OR.

"It used to take weeks in the hospital to recover from this procedure," Sorajja said. "Now it is essentially becoming an outpatient procedure."

Abbott joined a growing list of hospitals this month when it started using conscious sedation for transcatheter aortic valve replacements, or TAVRs, which involve threading a replacement valve inside an artery so it can regulate blood flow out of the heart. The University of Minnesota Medical Center also prefers conscious sedation for the procedure.

General anesthesia remains critical for many lifesaving surgeries, but studies are showing that it can result in health problems, said Dr. J.P. Abenstein, a Mayo Clinic physician and past president of the American Society of Anesthesiologists.

"When I was in training in the 80s, if patients were alive and kicking 24 hours after [procedures] then anesthesia was off the hook," he said. "Today, we realize there is long-term consequence to the heart, to the kidney, to the brain."

It doesn't always work: Abenstein said most doctors switched back to general anesthesia for certain gastrointestinal procedures because it was better for patients.

And even with TAVRs, one in 10 patients receiving conscious sedation nationwide are switched to general anesthesia because they can't sit still or complications occur.

"That is the downside," said Dr. Ganesh Raveendran, an interventional cardiologist at the U. "If there is a disaster or an emergent need, then there would be an emergency intubation and placement of the patient on a ventilator. People like to do those things in a controlled fashion rather than on an emergency basis."

Still, the benefit of keeping patients awake is enticing. A 2014 Emory University study compared 140 TAVR patients, primarily by the anesthesia they received, and found that those with conscious sedation were less likely to die and spent two fewer days in hospital care on average.

Doctors have long used conscious sedation for implanting stents, pacemakers and defibrillators, and now some are trying it in procedures to treat atrial septal defects — holes in the walls separating the heart's upper chambers.

'Shout if you feel anything'

Nothnagel, who became Abbott's second case of TAVR conscious sedation, had developed a condition called aortic stenosis, which occurs when the aortic valve sticks and inhibits blood flow. Stenosis grows more common with age and can lead to chest pain and heart attacks. He agreed to the approach when Sorajja first asked him. The Plymouth retiree took pride in sizing people up during his sales and marketing career, and he liked his doctor's confidence.

As the procedure began on a recent Wednesday, on the other side of the drape from where Sorajja was operating, Nothnagel's bushy eyebrows betrayed moments when he could feel the pokes and prods of the procedure. When Sorajja injected dye so he could see his patient's blood vessels on a monitor, Nothnagel said it felt hot and tasted bitter.

"Walter," Sorajja said, using his patient's formal name, "you are going to feel your heart beat getting a little faster. You may even feel lightheaded. The most important thing is we don't want you to move. Just shout if you feel anything."

A puff of dye illuminated Nothnagel's aorta on a screen, and the valve implant that had been threaded through a 5 millimeter incision in his chest.

Sorajja could expand the artificial valve just once, so he had to make sure it was in a spot that would push the failing natural valve aside and take over its role.

"I like the position there," he said to his team. "You guys like it?"

Feeling alert

Conscious sedation was unthinkable for the first generation of TAVRs, because the replacement valves were larger and inserted through wider incisions. The latest valves by companies such as Edwards Lifesciences and Medtronic are easier to implant.

Less anesthesia also appears to save money; the Emory study found TAVR patients cost $10,000 less when receiving conscious sedation, primarily due to shorter hospital stays.

For now, TAVRs have been reserved for patients too frail for open surgery. Risks of death and stroke during TAVRs are as high as 2 percent and 3 percent, respectively. But better results with less anesthesia could result in the approach becoming more common.

Minimal sedation was the right choice, Nothnagel said after the procedure, because he felt strong and alert. And he avoided having a breathing tube down his throat.

Any pressure or pinches during the procedure were worth the trade-off, though after a lifetime of other medical procedures, he considers himself a pretty tough guy.

"There's a red S on my chest," he said.

Jeremy Olson • 612-673-7744