Complementary and alternative medicine use by surgical patients

AORN Journal, Dec, 2002 by Carol L. Norred

The purpose of this national multisite study was to investigate surgical outpatient use of complementary and alternative medicine (CAM) during the two weeks before surgery. The study used a descriptive design consisting of a self-report questionnaire. (1)

RESEARCH QUESTIONS

The following research questions were addressed in this study.

* What is the incidence of preoperative CAM (ie, herbs, vitamins, dietary supplements, homeopathic medicines) use by. surgical patients?

* What is the frequency of surgical patient use of CAM that may interact with the anesthetic and subsequently alter hemostasis?

* What are the demographic characteristics of patients who report preoperative use of CAMs that may cause potential anesthetic-drug interactions resulting in excessive surgical bleeding?

SIGNIFICANCE TO NURSING

Considering that more than 28 million surgical procedures are performed annually in the United States, (2) a significant number of surgical patients may be consuming CAM preoperatively. The use of dietary supplements and herbal medicines has a growth rate of more than 10% per year, with herb and dietary supplement sales exceeding $17 billion in 2000. (3) Patients who use CAM preoperatively may be at increased risk for anesthetic-drug interactions. Herbs used for a specific purpose can produce unintended side effects and lead to toxic interactions when combined with other medications. The American Society of Anesthesiologists (ASA) recommends discontinuing use of herbal medicines at least two weeks preoperatively and warns that certain herbs can prolong the effects of anesthesia, increase the risk of bleeding, or raise blood pressure. (4)

LITERATURE REVIEW

Between 1990 and 1997 in the United States, the use of herbal medicines increased 380%, and the use of vitamins increased 130%. (5) Researchers from Harvard Medical School, Boston, report 22% of surgical patients take medicinal herbs, (6) and researchers in Texas found that 32% of preoperative patients consume botanical medicines. (7) A research study conducted at the University of Colorado, Denver, in 1999 found that 51% of surgical patients take up to 22 alternative medicines per patient, and 24% consume herbs. (8)

Anesthetics may interact with particular herbs, vitamins, or dietary supplements and result in increased surgical bleeding. (9) In a retrospective survey of adverse surgical outcomes in hospitals in Colorado and Utah, postoperative bleeding, the third most frequent adverse surgical event, accounted for 10.8% of all surgical adverse events, with an incidence of 47 per 10,000. (10) Excessive postoperative bleeding may be associated with the preoperative consumption of garlic, ginkgo, and multiple herb-drug combinations. Surgical cancellations because of abnormal coagulation laboratory analyses have been caused by the preoperative consumption of ginkgo, kava kava, St John's Wort, and feverfew. (11)

Case reports of herb-drug interactions often are sketchy. In a systemic review, 68.5% of herb-drug interaction case reports were "unable to be evaluated" because reliability was impeded. (12) Herb-drug interactions may be underreported in the literature because "too little is known about the consequences of interactions." (13) Human clinical trials and case reports of herb research may differ from in vitro or in vivo studies. Research on isolated components of herbs may reveal diverse potential for drug interactions. (14)

Consumers may believe that herbs are safe, natural substances. Botanical medicines, however, may have potent pharmacological effects, be of poor quality, be adulterated or contaminated, or vary in potency. (15) The 1994 Dietary Supplement Health and Education Act does not require manufacturers to provide explicit labeling about contraindications, medication interactions, side effects, or toxicities or to prove product safety or efficacy. (16)

Although most individuals who use alternative therapies combine them with conventional medicine, (17) the use of CAM often is not revealed to physicians. (18) Seventy percent of surgical patients who reported preoperative herb use in a survey also revealed that they did not disclose use to anesthesia care providers, (19) Orthodox practitioners often are not educated about alternative or indigenous medicines; therefore, "the consequences of ignorance will lead to adverse interactions in most cases." (20)

One group of researchers estimates that 15 million people in the United States are at risk for adverse interactions between CAM and other medications. Alternative medicine use is not limited to particular regions or demographics, but alternative medicines are used most often by college-educated Caucasian women older than 50 years of age. (21) The national incidence of surgical patient use of alternative medicines has not been reported previously in the United States; therefore, the scope, significance, and patterns of CAM use and its potential to cause anesthetic interactions that may alter hemostasis have not been determined.