Effect of Lavender on Vital Signs and Sleep in Intermediate Care Unit
Effect of Lavender on Vital Signs and Sleep in Intermediate Care Unit
Although aromatherapy has been used in a variety of settings, to our knowledge, no interventional studies of the outcomes have been conducted in patients in an IMCU. Our investigation is the first pilot study on the effects of aromatherapy on blood pressure, heart rate, respiratory rate, and perceived quality of sleep in the IMCU. The primary finding is that aromatherapy with 100% essential oil of lavender resulted in lower blood pressure after 6 hours of therapy. Other vital signs did not seem to be affected. Other researchers have had similar results. According to a systematic literature review, aromatherapy yielded positive improvement in physiological stress in 1 study, as indicated by heart rate, systolic blood pressure, and respiratory rate; caused no change in physiological stress in 2 studies; and had no effect on sleep quality in 1 study. Chien et al found similar results in vital signs and sleep improvement. In their study in 67 middle-aged women on the effect of lavender aromatherapy on the autonomic nervous system, the 34 women in the aromatherapy group had a significant decrease in mean heart rate. Chien et al also found that lavender aromatherapy led to a significant improvement in sleep quality when the women had a 20-minute exposure twice a week during a 12-week period. Using the St Mary's Hospital Sleep Questionnaire to measure sleep in a sample of 64 patients in 2 cardiac care units in Iran, Moeini et al found significant improvement in mean sleep quality scores after lavender aromatherapy. In their study, sleep was measured before and after therapy for 3 nights of lavender aromatherapy.
In our study, patients who had aromatherapy reported higher quality of sleep than did patients in the control group; however, the difference between the 2 groups was not significant. This finding may be related to the small number of patients in the study sample. The size of the study sample is a common limitation in the studies on lavender aromatherapy; most of the samples consist of a small number of patients and have flaws in the methods used. Thus, results should be interpreted with some degree of caution.
Louis and Kowalski measured not only vital signs but also pain, anxiety, depression, and sense of well-being in a group of 17 cancer patients who each received aromatherapy, a humidified-water treatment, and then no treatment during a 3-day period. The aromatherapy and the treatment with humidified water lowered blood pressure and pulse and had a positive effect on the other variables, but the differences were not significant. Perhaps larger sample sizes are needed to detect the subtle changes in vital signs that may occur with aromatherapy. Further testing in larger numbers of patients is needed to determine what strategies will improve sleep and restfulness in hospitalized patients.
Most of the patients in our study were women. Perhaps sleep is affected by sex-related factors, which were not explored. We used the Richard Campbell Sleep Questionnaire, which involves self-reporting by patients, and so our results are subjective. Other methods provide a more accurate measure of sleep. Polysomnography is the gold standard for measuring sleep quality and quantity; however, this method is expensive and requires continuous electroencephalographic monitoring and a specialized trained technician throughout the study. We did not have financial support for polysomnography in the pilot phase. Aromatherapy is typically conducted by using a heat source or a diffuser, which our infectious disease department prohibited in a hospital setting. We recognize that oxygen therapy could disrupt aromatherapy, but oxygen delivered via nasal cannula was allowed during the study because we thought patients would still be able to sense the lavender aroma and because most patients on the IMCU receive some form of oxygen therapy.
Our research was a pilot study; thus the number of patients in our sample might not have been adequate to detect subtle changes in vital signs and perceptions of sleep. Although we did monitor vital signs at baseline and throughout the night, we measured sleep only once, at the end of the intervention, because the Richard Campbell Sleep Questionnaire has not yet been validated as a tool for use before and after treatment. Studies in which a pretest-posttest design was used or sleep was measured more than 1 night were more likely to have significant results.
Research on aromatherapy has several methodological challenges. In this pilot study, the data collectors, care providers, and participants knew the group assignment of each patient because of the lavender odor at the bedside. This situation could introduce both interviewer and participant bias. In addition, determining the purity of the oil and how much a patient actually sensed or perceived the aroma is difficult and could introduce intervention bias. Despite these challenges, patients in the treatment group had higher sleep scores than did the control group for most questions, suggesting that lavender aromatherapy may be a promising intervention to enhance perceived sleep. On the basis of our results, we suggest that future studies be conducted in larger numbers of patients, with a pretestposttest design and use of methods to reduce bias. Because of the adverse effect of poor sleep quality in critically ill patients, research on ways to improve sleep in acute care settings should continue.
Discussion
Although aromatherapy has been used in a variety of settings, to our knowledge, no interventional studies of the outcomes have been conducted in patients in an IMCU. Our investigation is the first pilot study on the effects of aromatherapy on blood pressure, heart rate, respiratory rate, and perceived quality of sleep in the IMCU. The primary finding is that aromatherapy with 100% essential oil of lavender resulted in lower blood pressure after 6 hours of therapy. Other vital signs did not seem to be affected. Other researchers have had similar results. According to a systematic literature review, aromatherapy yielded positive improvement in physiological stress in 1 study, as indicated by heart rate, systolic blood pressure, and respiratory rate; caused no change in physiological stress in 2 studies; and had no effect on sleep quality in 1 study. Chien et al found similar results in vital signs and sleep improvement. In their study in 67 middle-aged women on the effect of lavender aromatherapy on the autonomic nervous system, the 34 women in the aromatherapy group had a significant decrease in mean heart rate. Chien et al also found that lavender aromatherapy led to a significant improvement in sleep quality when the women had a 20-minute exposure twice a week during a 12-week period. Using the St Mary's Hospital Sleep Questionnaire to measure sleep in a sample of 64 patients in 2 cardiac care units in Iran, Moeini et al found significant improvement in mean sleep quality scores after lavender aromatherapy. In their study, sleep was measured before and after therapy for 3 nights of lavender aromatherapy.
In our study, patients who had aromatherapy reported higher quality of sleep than did patients in the control group; however, the difference between the 2 groups was not significant. This finding may be related to the small number of patients in the study sample. The size of the study sample is a common limitation in the studies on lavender aromatherapy; most of the samples consist of a small number of patients and have flaws in the methods used. Thus, results should be interpreted with some degree of caution.
Louis and Kowalski measured not only vital signs but also pain, anxiety, depression, and sense of well-being in a group of 17 cancer patients who each received aromatherapy, a humidified-water treatment, and then no treatment during a 3-day period. The aromatherapy and the treatment with humidified water lowered blood pressure and pulse and had a positive effect on the other variables, but the differences were not significant. Perhaps larger sample sizes are needed to detect the subtle changes in vital signs that may occur with aromatherapy. Further testing in larger numbers of patients is needed to determine what strategies will improve sleep and restfulness in hospitalized patients.
Limitations and Recommendations
Most of the patients in our study were women. Perhaps sleep is affected by sex-related factors, which were not explored. We used the Richard Campbell Sleep Questionnaire, which involves self-reporting by patients, and so our results are subjective. Other methods provide a more accurate measure of sleep. Polysomnography is the gold standard for measuring sleep quality and quantity; however, this method is expensive and requires continuous electroencephalographic monitoring and a specialized trained technician throughout the study. We did not have financial support for polysomnography in the pilot phase. Aromatherapy is typically conducted by using a heat source or a diffuser, which our infectious disease department prohibited in a hospital setting. We recognize that oxygen therapy could disrupt aromatherapy, but oxygen delivered via nasal cannula was allowed during the study because we thought patients would still be able to sense the lavender aroma and because most patients on the IMCU receive some form of oxygen therapy.
Our research was a pilot study; thus the number of patients in our sample might not have been adequate to detect subtle changes in vital signs and perceptions of sleep. Although we did monitor vital signs at baseline and throughout the night, we measured sleep only once, at the end of the intervention, because the Richard Campbell Sleep Questionnaire has not yet been validated as a tool for use before and after treatment. Studies in which a pretest-posttest design was used or sleep was measured more than 1 night were more likely to have significant results.
Research on aromatherapy has several methodological challenges. In this pilot study, the data collectors, care providers, and participants knew the group assignment of each patient because of the lavender odor at the bedside. This situation could introduce both interviewer and participant bias. In addition, determining the purity of the oil and how much a patient actually sensed or perceived the aroma is difficult and could introduce intervention bias. Despite these challenges, patients in the treatment group had higher sleep scores than did the control group for most questions, suggesting that lavender aromatherapy may be a promising intervention to enhance perceived sleep. On the basis of our results, we suggest that future studies be conducted in larger numbers of patients, with a pretestposttest design and use of methods to reduce bias. Because of the adverse effect of poor sleep quality in critically ill patients, research on ways to improve sleep in acute care settings should continue.
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