August 3, 2003
People with natural red hair need about 20 perecent more anesthesia than people with other hair colors, U of L anesthesiologists report.
The startling discovery not only suggests that redheads are more sensative to pain but offers insight into how anesthesia works, says U of L anesthesiologists Edwin Liem (picture above).
“Red hair is the first visible human trait, or phenotype, that is linked to anesthestic requirement,” he says. “In a nutshell redheads are more likely to experience more pain and therefore require more anesthesia to alleviate that pain.”
Liem, who reported the finding at a meeting of the American Society of Anesthesiologists in Orlando, Fla., says it is important news for specialists who monitor patients during surgery.
“The art and science of anesthesiology is choosing the right dose,” he says. “there is very little difference between the effective dose and the toxic dose of most anesthetics. Patients can awaken during surgery if they are given insufficient anesthesia or suffer cardiac and pulmonary complications when they are given too much.”
Liem says scientists do not fully understand how anesthesia works, but the finding offers clues, as people with red hair have a certian genetic variant.
Liem says redheads may have a “dysfuntional melanocortin 1 receptor” on the pigment cells for skin and hair. The receptor may trigger a feedback mechanism that releases a hormone needed by these cells. Yet the same hormone also stimulates a brain receptor that increases pain sensitivity.
Liems’s team looked at a group of white women, aged 19 to 40, who had either dark or natural bright red hair. They found it significantly more anesthesia (inhaled desflurane was used) to keep the redheads comfortable during surgery.
The research was conducted at U of L’s Outcomes Research Institute, which studies the results of particular healthcare practices and interventions.
Liem says more research is needed before anesthesiologists can develop new guidelines for red-headed patients. In the meantime, he advises them to talk with their anesthesiologists about this link prior to surgery.