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The American
Association of Nurse Anesthetists (AANA) recently published a study
reporting that patients who use complementary and alternative medicines within
two weeks of surgery may experience adverse side effects.
The study, titled Use of
Complementary and Alternative Medicines by Surgical Patients,
appears in the February 2000 issue of the AANA Journal and evaluates the
interaction of vitamins, herbs, dietary supplements and homeopathic medicines
with anesthetics. Based on a survey of 500 elective surgical outpatients from
the University of Colorado Health Sciences Center (UCHSC) in Denver, the study
categorizes complementary and alternative medicines (CAM) according to their
potential to cause "adverse effects" with drugs used during surgery.
The study, which underscores the relationship between conventional and
unconventional medicines, profiles patient use of CAM.
Of the 500 patients
surveyed, more than half consumed one or more types of alternative medicines
during a two-week period before surgery. Garlic and cranberry represented the
most common herbal substances consumed followed by echinacea, gingko and ginseng,
respectively. The vitamins most frequently taken included vitamin C,
multivitamins and vitamin E. The survey also indicates that 220 patients took 31
types of dietary supplements including calcium, fish oil, magnesium or zinc.
More popular
with women than men, the study found that some alternative medicines can
increase bleeding and prolong coagulation during surgery. Twenty-seven percent
of patients surveyed consumed vitamins, herbs and supplements that could
increase the time it takes for blood to clot. Alternative medicines that may
prolong coagulation include alfalfa, chamomile, some Chinese herbs, garlic,
ginko, kava, licorice, vitamin E and fish oil.
Fifty-eight patients
or 12 percent of survey respondents took herbs that could adversely impact blood
pressure levels during surgery. Black cohosh, used to treat menopause, menstrual
cramps and osteoporosis, can lower a patient’s blood pressure. St. John’s
Wort, used to control depression, can raise blood pressure as well as cause
confusion, agitation and drowsiness in surgical patients.
The study also links
some herbs to heart irregularities and others to electrolyte imbalance. Ephedra,
an herb used to treat coughing, asthma and weight loss, can trigger arrhythmia
and high blood pressure while licorice, used to control coughing and soothe sore
throats, can raise the risk of hypokalemia, a potassium deficiency that can
cause arrhythmia. Herbal diuretics, which increase urine output, also can deplete potassium levels and cause electrolyte imbalance. Sedative herbs, like
kava, can cause severe drowsiness when combined with the hypnotic drugs used
during surgery.
Carol Norred, a
Certified Registered Nurse Anesthetist (CRNA), researcher and PhD student at
the UCHSC Department of Anesthesiology and School of Nursing, believes that more
scientific research is needed to safely integrate CAM into the management of
surgical patients. Norred, who spearheaded Use of Complementary and
Alternative Medicines by Surgical Patients, believes an open dialogue
between patients and providers can prevent complications related to the use of
unconventional medicines.
"Most patients
who take alternative medicines never tell their providers about it. This can
compromise a patient’s safety if these medicines aggravate a health condition
or interact poorly with the drugs used during surgery. As advocates of patient
safety, we at the AANA advise patients to disclose information about CAM use
prior to surgery," she says.
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