David Hoyt, MD, Predicts a New World of Fluid Resuscitation

As a youngster, trauma surgeon David Hoyt, MD, FACS, dreamed of becoming a famous playwright on Broadway. He spent two years in the Big Apple writing plays and even enrolled in film school. But then adulthood hit, or, as Hoyt puts it, “At age 21, I finally got serious.”

The son of an orthopedic surgeon, Hoyt soon found that his true passion lay much closer to home. Today, Hoyt is the Burn and Surgical Intensive Care Chief at University of California San Diego (UCSD) Medical Center and a professor and interim chair of UCSD’s surgery department. In October, Hoyt will present the Scott B. Frame Memorial Lecture on the topic of trauma and fluid resuscitation at the EMS EXPO and NAEMT Annual Meeting in Atlanta, GA.

Advances in Trauma Care

Hoyt, a veteran clinician, has served in leadership roles with numerous prestigious surgical associations, including the American Association for Surgery and Trauma and the American College of Surgeons Committee on Trauma. Hoyt constantly advocates for medical advances in both surgery and trauma as a means to improve patient outcome.

While in high school, Hoyt volunteered in the emergency department at Children’s Hospital in Akron, OH, treating wounded children.-“During that time, I was exposed to some of the original paramedic programs, which developed in northeastern Ohio, including Akron,” he says.

Hoyt earned his medical degree from Case Western Reserve University in 1976 and completed his surgical residency and research fellowship at UCSD and Scripps Immunology Institute in 1984.

Trauma care has changed a lot since Hoyt first began work as a trauma surgeon nearly two decades ago. Physicians are better trained today, he says, and patients benefit from effective prevention programs, paramedic services and designated trauma centers. Automobile makers are building safer cars, and societal violence has declined in recent years, which has helped reduce posttraumatic mortality. Despite these advances, trauma care still can be improved, says Hoyt.

One of the most critical issues in trauma care is the debate over fluid resuscitation, or how to best replace blood volume in the absence of blood transfusion. Hoyt hopes to find a solution in his own backyard as San Diego embarks on the first prehospital study comparing the current standard treatment of saline and lactated Ringer’s to an experimental oxygen-carrying blood substitute called Polyheme.

Polyheme clinical trials have begun in San Diego on aeromedical services and are expected to begin with San Diego-based ground crews later this summer. Polyheme is also being tested in Denver, CO. Hoyt says he is confident that oxygen-carrying therapeutics could be a viable substitute to saline, but field testing is the only way to be sure. If Hoyt had his way, there would also be field studies addressing the current controversy over low-volume vs. high-volume fluid resuscitation.

According to Hoyt, fluid requirements differ depending on the point at which care is administered. “Early on, prior to getting surgical control of bleeding, giving too much fluid is bad,” he says. “After surgical control has been established, then the challenge is to decide on what is the appropriate end-point to give fluid.”

Until more is known, Hoyt recommends restricting fluids—especially during long transports—to offset the risk of increased bleeding.

“When there is a long transport time, it’s important to be careful about giving too much fluid,” he says. “You have to trade off the risk of giving fluid and increasing bleeding vs. not giving so much fluid and creating hypoperfusion, which can result in organ damage.”

Blood Substitutes

Polyheme and other oxygen-carrying products are specifically designed to duplicate a key function of the blood: to transport oxygen to the cells and waste gases away from them. Hoyt, who has been working with Polyheme’s manufacturer, Northfield Laboratories, for years, admits there are potential risks with Polyheme, including rash, increased blood pressure, kidney or liver damage and viral infections, but, he says, the risks are low.

“Polyheme only lasts for about 24 hours; it is cleared through the urine,” Hoyt explains. “The study is designed to give six units in the first 12 hours. Once the patient has survived and gone through surgery, the next day you need to decide whether to give a blood transfusion.”

Hoyt says that it is only a matter of time before the FDA approves blood substitutes for field use. In his view, in addition to Polyheme, there are several products in late-stage clinical trials that hold promise, including Biopure Corp.’s Hemopure and Hemosol Inc.’s Hemolink.

Hoyt says he intentionally has no financial interest in any of these companies; he just wants to identify a solution that is best for patients.

A Vision for the Future

If Hoyt is correct, field providers can expect many more changes in prehospital trauma care in the coming decade.

Fluid resuscitation using oxygen-carrying substances is just the beginning. Hoyt anticipates other substances, possibly antioxidant therapies and multivitamins, to be added to the mix, too.

“It sounds funny, but when a patient is extremely injured, providing a way to bind up some of the oxidant stress that is created by injuries may be an advantage,” Hoyt says.

Better ventilation techniques are also important, he adds. “Doing studies and then teaching people how to do it correctly is the challenge.”

Field studies evaluating new cooling techniques to preserve tissue function and new agents to stop bleeding are also on the horizon, according to Hoyt. He also proposes that forming clinical trial networks joining paramedics and trauma hospitals from various nationwide centers could positively impact trauma care in the same way that in-patient hospital trials have successfully led to new cancer therapies.

Learn More

Hoyt will speak on The History and Current Study of Prehospital Fluid Therapy on Thursday, October 21 at 7 p.m. at the Georgia World Congress Center in Atlanta, GA, as part of EMS EXPO and the NAEMT Annual Meeting. He will review the history of prehospital fluid resuscitation, current questions to be answered, and how participation in prospective randomized clinical trials in the prehospital arena will represent a partnership with EMS personnel in the future.