lood is thicker than water. Four times thicker to be precise. Still, controlling blood flow can pose many problems. Conserving blood in the preoperative and perioperative setting is vital to positive patient outcomes. To help reach those positive outcomes, various hemostatic agents may be used to conserve patient blood levels.
"Effective blood management keeps patients from having to receive a blood transfusion. Not only does this keep the patient from potentially compromising his or her immune system, it avoids a costly and unnecessary [procedure]," said Vangie Dennis BSN, RN, CNOR, CMLSO, administrative director, Spivey Station Surgery Center, Jonesboro, GA.
Many different items fall under the umbrella of hemostatic agents. Ranging from gauze all the way to fibrin-based surgical sealants, many different hemostatic agents are available to nurses. The key is picking the right one for the right application.
"The biggest thing people need to know about hemostatic agents is that there are different types that are used for different purposes," Dennis said.
Broadly speaking, there are three different types of hemostatic agents: absorbable hemostatic agents, surgical sealants and surgical adhesives. A fourth tool, hemostatic thermal tools such as ultrasonic scalpels and lasers, may be added to any hemostatic repertoire.
Testing & Evolution
The various hemostatic agents currently available have been rigorously tested in both laboratory and clinical settings. Yet, many of these hemostatic agents have received their most rigorous testing on the battlefield.
"Our research primarily deals with battlefield trauma. Getting the patient stabilized and into the perioperative setting is our end goal in studying these hemostatic agents," said James Burgert, MSNA, CRNA. Burgert serves as staff nurse anesthetist at Brooke Army Medical Center (BAMC) in San Antonio, TX.
Burgert and other researchers at BAMC have been studying the safety and effectiveness of hemostatic agents. According to Burgert, a very clear evolution has occurred within the types of hemostatic agents available.
"Early hemostatic agents used granular, porous, mineral-based substances to absorb plasma and concentrate platelets and clotting factors at the hemorrhage site," he said. "However, this first generation of hemostatic agents generated an exothermic reaction in excess of 140° F. This reaction caused increased potential tissue damage to the patient and could potentially cause injury to the provider if the substance came in contact with their mucous membranes."
Though plagued by unintended side effects, these early hemostatic agents showed promise. The next step was to find an absorbable hemostatic agent that did not induce an exothermic reaction.
"Soon thereafter a second generation of hemostatic agents arose made of chitin - ground up crustaceans - that acted as a natural hemostatic agent," Burgert said. "By pouring these into the wound, bleeding would cease and there was no adverse heat generation. Some plant-based polysaccharides were also developed for the same purpose," Burgert said.
Although the heat issue had been overcome, early hemostatic agents posed other significant problems when it came to application. "All of the early hemostatic agents used in a combat setting were a particulate poured into the wound," Burgert said. "The problem was that high velocity hemorrhage would eject the particulate before it could work. Even worse was that there was the possibility some of the particulate could enter into the patient's circulation, causing an embolic event," he explained.
A new generation of absorbable hemostatic agents aims to correct these problems. "Recently, a third generation of hemostatic agents has been developed that consists of gauze-like dressings impregnated with the hemostatic agent. With these you have the benefits of the hemostatic agent combined with the benefits of traditional wound management. The mass of the dressing fills the wound cavity, increasing direct pressure on the wound, while the hemostatic agent concentrates platelets and clotting factors," Burgert said.
Many Agents Available
The rigors of combat call for unique hemostatic agents. Even though the operating room is dramatically different than the battlefield, a large degree of hemostatic agent crossover occurs.
"Historically, things that are developed by the military will eventually trickle down into civilian care," said Burgert, noting the use of penicillin began in the military. "What the military is doing with hemostatic agents will certainly become incorporated into civilian care."
Absorbable hemostatic agents are currently being used in the perioperative setting. Some may be composed of cellulose, collagen, plant-based polysaccharide or gelatin-based materials, while some use bovine thrombin to promote clotting.
"While thrombin is a naturally occurring mechanism of hemostasis, bovine thrombin is an animal-derived, cheaper alternative to human thrombin," Dennis said. "More and more we are seeing adverse reactions and patient hypersensitivity. The bottom line is that nurses need to know the products they are using."
Along with the absorbable hemostatic agents, sealants and adhesives are available. Surgical adhesives may be used as adjunctive therapy alongside sutures or staples. Likewise, surgical sealants may be used as adjunctive therapy when bleeding is uncontrolled by standard suture, ligature or electrosurgical methods.
"Surface agents can be used to create a seal at the bleeding site. These are essentially adhesives that hold two tissue surfaces together. However, it is important to note that there are some types of arterial bleeding that these will simply not work on," Dennis said.
Another option for intraoperative blood management comes in the form of electrosurgical hemostatic agents, such as ultrasonic scalpels, lasers and vessel sealing technology, but can result in adverse side effects. "Many of these can lead to tissue death within 2 seconds of use," Dennis warned. "Nurses must consider the complications related to the device."
Of all the hemostatic agents available, the most effective method has to occur before the patient enters the operating room. "Before relying on hemostatic agents, nurses need to rely on a preoperative assessment," Dennis said. "This is a clinical fundamental that provides early intervention for high-risk patients. Preoperative anemia can be addressed ahead of time by increasing red blood cell mass, for instance, while an assessment of current medications can go a long way in saving blood in the intraoperative setting."
In some form or another, nurses are involved in hemostatic agents. That interaction may occur in the OR with the nurse applying sealant to a leakage of blood. Or, nurses may come into contact with hemostatic agents when they least expect it.
"If you look at any major disaster such as the tornado in Joplin or Hurricane Katrina, it stretches the limits of normal medical response," Burgert said. "It is an all-hands-on-deck situation; it is like little league where everyone gets to play. Nurses will be applying hemostatic agents right next to other first-responders."
Even when nurses are not interacting with sealants or absorbable hemostatic agents, they are still assisting in blood management. Preventing unnecessary blood loss through pre- and postop assessment is perhaps the most effective means of blood management.
"Preoperative and postoperative assessments are crucial to blood management," Dennis said. "Attending to those will prevent excessive bleeding better than any hemostatic agent."
A. Trevor Sutton is a frequent contributor to ADVANCE.