Norepinephrine May Increase Chances Of Survival In Hemorrhagic Shock

Main Category: Blood / Hematology
Also Included In: Aid / Disasters;  Clinical Trials / Drug Trials
Article Date: 25 Sep 2007 - 0:00 PDT

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For trauma patients with shock caused by severe bleeding, giving the drug norepinephrine along with initial fluid replacement might help to improve the chances of survival.

The October issue of the journal Anesthesiology features a study in rats suggesting that fluid resuscitation plus norepinephrine could offer a new approach to reducing the risk of death for trauma victims with uncontrolled bleeding and shock. "We have demonstrated that using norepinephrine in the early phase of an animal model of uncontrolled hemorrhagic shock allowed us to improve survival, reducing the amount of fluid infusion and reducing bleeding volumes," comments Dr. Frederic Adnet of Avicenne Hospital, Bobigny, France. Norepinephrine is a natural substance released into the bloodstream during periods of stress, such as hemorrhage.

The researchers designed a study in rats to simulate the situation in which a person suffers head injury combined with uncontrolled bleeding (hemorrhage). The study followed a model that is very commonly used in animal research for studying resuscitation in trauma patients, before the techniques are tried in clinical studies. The animals were under anesthesia (asleep) during the procedure.

Resuscitation was performed using fluid replacement alone or with different doses of norepinephrine. The study also evaluated the effects of resuscitation at normal versus lower-than-normal blood pressure. Norepinephrine is a vasopressor, or vasoconstrictor, which means that it causes the blood vessels to narrow. Under current guidelines, norepinephrine is used for patients in shock only when they don't respond to initial fluid resuscitation.

At the proper dose, using norepinephrine with resuscitation fluids significantly improved the chances of survival. Norepinephrine also reduced the amount of fluid needed for resuscitation, as well as the amount of blood lost.

"We also demonstrated that using norepinephrine allowed us to restore a normal blood pressure without altering survival, which is one of the most important aims in head-injured trauma patients," adds Dr. Adnet.

Many patients especially young people die every day from bleeding caused by multiple trauma. Recent studies have challenged current guidelines for early resuscitation of trauma patients with uncontrolled hemorrhagic shock.

Adding norepinephrine to fluid resuscitation for uncontrolled bleeding and shock appears to be a promising approach to reducing the risk of death, and possibly for improving final outcomes in trauma survivors, the researchers believe. Dr. Adnet adds, "It would be interesting to evaluate the benefits of this new type of resuscitation through a clinical research study of patients with the common problem of profound hemorrhagic shock."

With further study, the use of fluid resuscitation with norepinephrine might be an attractive alternative to treatment of trauma patients with uncontrolled hemorrhagic shock, writes Dr. Philippe Van der Linden of Centre Hospitalier Universitaire Brugmann-HUDERF in Brussels, Belgium, in an accompanying editorial. "Indeed, the combined use of fluids and vasoconstrictors in order to restore and maintain a predefined target perfusion [blood] pressure might be the more efficient approach, while reducing the risks of side effects associated with the use of each treatment alone."

While a number of studies of anesthetic drugs in animals have provided useful direction for further research, it is important to note that animal studies are considered basic science and their findings do not always translate to the complex physiological system of human beings.

For additional information on this study, go to http://www.anesthesiology.org.

Founded in 1905, the American Society of Anesthesiologists is an educational, research and scientific association with 41,000 members organized to raise and maintain the standards of the medical practice of anesthesiology and improve the care of the patient.

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