A research team headed by Dr. Patricia Molina and colleagues from Louisiana State University Health Sciences Center found that laboratory rats given enough alcohol to mimic a binge-drinking episode undergo a greater drop in blood pressure following even a small blood loss than do rats not exposed to alcohol. The intoxicated rats also take longer to return to normal blood pressure after adequate fluid is returned to the body through the equivalent of an IV drip.
Both these findings have enormous implications for trauma patients and the physicians who treat them, says Dr. Molina. Delayed normalization of blood pressure prolongs the period of time tissues have inadequate oxygen supply, a particularly disastrous situation for heavy oxygen-using organs like the brain, liver and kidney. Abnormally low blood pressure — and the body’s altered neural and hormonal signaling to restore normal blood pressure —negatively impact trauma victims’ response to surgery, anesthesia and mechanical ventilation, including increasing the risk of infection.
The LSU study is the first to isolate and explain the mechanism through which alcohol intoxication causes these negative effects. When animals, rats or humans, lose even a relatively small amount of blood, the brain immediately attempts to restore blood pressure to pre-blood loss levels by activating neurons and releasing chemical mediators into the circulation. Dr. Molina’s team found that alcohol intoxication severely impairs this sequence of events, causing lower amounts of the chemicals to be released into the circulation, thereby delaying rapid recovery of the circulatory system.
Much research has been done in institutions across the nation on how to decrease the incidence of injury in alcohol abusing individuals, but Dr. Molina says very little research has focused on understanding how the bodies of intoxicated patients cope with injury. Understanding the mechanism of impaired compensatory responses to blood loss in intoxicated but otherwise healthy individuals opens the way to finding clinical approaches to decrease the severity of outcome and care-related costs for these patients.