Intraoperative anesthesia requirements increase when a patient has high baseline anxiety and stress. These patients also have a more difficult recovery from anesthesia. Accordingly, patients are given anxiolytic and sedative drugs before surgery, but these may delay discharge from the hospital. Aromatherapy may be able to reduce anxiety before a procedure. The purpose of this randomized, blinded, controlled study was to evaluate whether lavender (Lavandula angustifolia, Lamiaceae) oil aromatherapy could decrease stress, bispectral index values (using electroencephalogram to determine level of consciousness during sedation), and pain of needle insertion in a surgical setting.
Healthy subjects (n = 30, mean age 21 years) participated in this study conducted at Kyungpook National University Hospital in Daegu, South Korea. Subjects were randomly assigned into lavender treatment or control groups. Subjects arrived at the preoperative area, rested on a bed for 5 minutes, and then baseline bispectral index (BIS) values were calculated via electrodes placed on the scalp. Next, the subjects were asked to score their stress and tension on a visual analogue scale (VAS; 0 = no stress to 10 = maximum stress). One minute later, a 25-gauge needle was inserted 3 mm into the skin of the non-dominant forearm and kept there for 30 seconds. The subject rated pain intensity on a VAS (0 = no pain to 10 = worst pain imaginable).
Next, subjects in the lavender group received oxygen for 5 minutes via a face mask coated with 2 drops of 2% lavender oil, which was applied with a cotton swab to the inside of the mask. The lavender oil (100% pure lavender oil; Plant Life Natural Body Care; San Clemente, California) was diluted to 2% lavender oil with jojoba (Simmondsia chinensis, Simmondsiaceae) oil. The subjects in the control group received oxygen for 5 minutes through a face mask with no lavender oil. Immediately after receiving treatment, the subjects were transported to the operating room, and then BIS values were measured at 5, 10, 15, 20, and 25 minutes after inhalation therapy. The subjects scored their stress level 6 minutes after inhalation treatment, and 1 minute later, a needle was inserted similar to baseline. The subjects rated pain intensity from 0 to 10. Adverse effects were recorded.
At baseline, both groups had similar levels of stress, pain intensity at needle insertion, and BIS values. Lavender oil significantly reduced the stress level (P < 0.001) and pain intensity (P < 0.001) compared with the control. BIS levels at 5, 10, 15, and 20 minutes after aromatherapy inhalation were significantly lower than after control inhalation (P < 0.001 for all). There was no between-group difference in BIS 25 minutes after therapy. No adverse effects were reported.
The authors conclude that lavender inhalation significantly reduced BIS values, stress levels, and pain intensity of needle insertion. The exact mechanism of action is unknown. The advantages of aromatherapy with lavender oil is that it can be easily applied, is safe, has a low cost, would not prolong sedation after surgery or increase the incidence of vomiting, and can improve patient satisfaction. Aromatherapy may be helpful in controlling preoperative stress and fear. Although not assessed here, the findings may extend to the outpatient setting where patients need to give blood. The appropriate dose and efficacy would need to be assessed.—Heather S. Oliff, PhD