June 24, 1998
Some anesthesiologists may be accidentally inhaling too much of the potent anesthetic gas halothane when they tend to their patients, possibly putting themselves at high risk for liver injury, according to a study by researchers at Johns Hopkins and the National Institutes of Health.
The investigators found that 23 percent of pediatric anesthesiologists and 9 percent of general anesthesiologists showed higher than normal levels of antibodies to p-58, a liver protein generally found in people with hepatitis caused by exposure to halothane. The antibody level in the doctors was similar to that of one in five patients tested who had halothane hepatitis. However, none of the anesthesiologists showed signs of outright liver disease.
"It's still too early to tell whether the antibodies mean the anesthesiologists will get liver disease, or if the antibodies may be protecting them," says Dolores B. Njoku, M.D., lead author of the study and an instructor of anesthesiology and critical care medicine at Hopkins. "But there are safety precautions that anesthesiologists should take, such as making sure their masks fit tightly and not leaving the gas on during operating room preparation."
Results of the study were presented at a recent meeting of the Society for Pediatric Anesthesia in Phoenix.
Researchers collected blood samples from 53 general anesthesiologists, 13 pediatric anesthesiologists, 21 patients who had developed hepatitis as a result of exposure to halothane, and 21 patients who had no exposure to anesthetic gases. They then measured autoantibodies to p-58 and P4502EI, another protein linked to halothane hepatitis.
When testing for P4502E1, the researchers found that 8 percent of the pediatric anesthesiologists, 4 percent of the general anesthesiologists and 62 percent of the halothane hepatitis patients had significant levels of antibodies.
"The findings of this study indicate that some anesthesiologists are sensitized to the same liver proteins that have been associated with halothane hepatitis," Njoku says. "It remains to be determined why these individuals have not developed liver injury."
The study's other authors were Robert S. Greenberg, M.D., and Jackie Lee Martin Jr., M.D., of Hopkins; and Mohammed Bourdi, Ph.D., and Lance Pohl, Pharm.D., Ph.D., of the National Heart, Lung and Blood Institute.