Review question/objective

Is inhalation aromatherapy effective in reducing patients' anxiety before colonoscopy?

The objective of this review is to examine the effectiveness of inhalation aromatherapy in reducing patients' anxiety before colonoscopy.

Background

In 2012, colorectal cancer was the fourth most common cancer in the world for both sexes, and the number of deaths due to colon cancer was 694,000 that year.1 Colonoscopy is frequently used as the first investigation when there is any suspicion of lower gastrointestinal tract symptoms2 and is currently considered the gold standard for detection of colonic neoplasia.3 The demand for colonoscopy is increasing in importance worldwide.4 The approximate number of colonoscopies performed per year in the USA is 14 million.3 However, colonoscopy is often viewed as an invasive procedure with the potential for embarrassment, discomfort and worry related to potential findings.5 Additionally, colonoscopy may induce a physiological response, such as a metabolic or endocrine stress response.6 These concerns can result in anxiety that unfavorably decreases the patient's cooperation and satisfaction with the procedure.7

Up to one-third of outpatients experience alarmingly high anxiety levels as assessed by the State-Trait Anxiety Score Inventory before gastroscopy or colonoscopy.8 Furthermore, a higher State-Trait Anxiety Score Inventory score prior to colonoscopy is associated with increased pain and nausea during colonoscopy.9,10

To reduce anxiety before colonoscopy and pain during colonoscopy, sedation is commonly used in Western countries.11 A previous study showed that patients who had undergone colonoscopy with sedation felt lower anxiety and fear compared with those who had undergone colonoscopy without sedation and those who had never had a colonoscopy before.12 Furthermore, patients who were sedated during colonoscopy felt more satisfied with the procedure and expressed more acceptability of future colonoscopy than non-sedated patients.

However, the use of sedation is risky and costly.13 Sedation may also contribute to the occurrence of cardiovascular events and is associated with the risk of cardio-respiratory complications.14 In sedated patients, cardiopulmonary problems account for approximately 50% of complications. An increased amount of sedation may result not only in an increase in the likelihood of sedative-related complications and use of more medications,10,15,16 but also a delay in postoperative recovery.17 These negative experiences for patients will lead to potential anxiety about colonoscopy and noncompliance with future examinations, potentially creating a vicious circle.18 Therefore, physicians need to try any approach to reduce anxiety without increasing the amount of sedation during colonoscopy.

Non-pharmacological approaches can be used without increasing the amount of sedation to reduce patients' anxiety before invasive procedures. A systematic review was conducted to identify the effects of various non-pharmacological interventions on reducing anxiety in women undergoing colposcopy.19 This review concluded that interventions by music or information videos significantly reduced anxiety compared with non-intervention. However, information leaflets or counselling had no significant effect on reducing anxiety.

A meta-analysis by Bechtold et al. evaluated the effect of music therapy on the overall experience during colonoscopy in eight studies.20 The review concluded that the intervention was effective for significantly improving the overall experience in relation to anxiety, discomfort and satisfaction. However the control groups of these retrieved studies were not blinded. Therefore, the evidence for the effect of music therapy on "anxiety" during colonoscopy remains weak.

The music therapy during colonoscopy was effective for significantly reducing procedure time and the amount of sedation during colonoscopy in a meta-analysis of eight studies.21 The reason for the reduction in sedation and the colonoscopy duration may be that patients in the music group were more relaxed and felt less anxious, and the surgeons could therefore complete the procedure in a shorter period of time than with the non-intervention group. However, surgeons were blinded in only two studies where the patients in the placebo group used personal headphones without listening to music. Subgroup analysis by blinding status was not conducted. Further, the reduction in the mean procedure time was approximately two minutes, which did not appear to be clinically meaningful. However, no harmful effects from listening to music were reported in any study, and the authors concluded that music should be recommended during colonoscopy.

Sensuous intervention, such as music, may be effective during colonoscopy; however, the evidence was poor, and the effect of non-pharmacological approaches needs to be more critically examined.

As a sensuous intervention similar to music, aromatherapy has received attention in recent years and has been compared with music for reducing anxiety.22,23 Aromatherapy is defined as the therapeutic use of essential oils from plants for improvement of physical, emotional and spiritual well-being.24 Aromatherapy is currently recognized as a tool of holistic nursing care in many countries, and the positive effect most consistently found from aromatherapy is reduced psychological distress, such as anxiety.25

Aromatherapy is administered through a cutaneous, oral or nasal route. The cutaneous route is often via a massage, which is the main method in aromatherapy.26 However, aromatherapy massage requires more human and financial resources than other interventions. Therefore, aromatherapy massage is not cost effective to use before colonoscopy. An alternative therapy is inhalation aromatherapy. The essential oils used in inhalation aromatherapy are delivered through an electric diffuser or vaporizer. The aroma of the essential oil evaporates and stimulates the olfactory senses.26 The molecules of inhaled essential oils transmit their signals via olfaction and stimulate the brain to produce 5-hydroxytryptamine, which is important in the regulation of moods.27

Several clinical trials of inhalation aromatherapy to reduce patients' anxiety before colonoscopy have been published.28,29 However, systematic reviews on the anxiolytic effects of inhalation aromatherapy have not been conducted. Therefore, the present systematic review will synthesize the available evidence to consider the effectiveness of inhalation aromatherapy in reducing patients' anxiety before a colonoscopy.

Inclusion criteria

Types of participants

This review will consider studies that include participants of all ages, sexes and with any indication for colonoscopy. A sub-group analysis by sedation status, if it can be identified, will be conducted. There are no exclusion criteria. However, the reviewers will consider conducting sub-group analyses according to the types of participants if the participants' characteristics include potential confounders, such as disease type.

Types of intervention(s)/phenomena of interest

This review will consider studies that evaluate inhalation aromatherapy before a colonoscopy. The review will exclude studies that do not use essential oils in the intervention, even if aroma is mentioned. The control group using placebo scent without essential oils will be considered for inclusion as the comparison with the intervention group.

Types of outcomes

This review will consider studies that include any anxiety scale as subjective outcome measures, such as the State-Trait Anxiety Inventory, Hospital Anxiety and Depression Scale, Beck Anxiety Inventory and Visceral Sensitivity Index. The objective outcomes that are considered to influence anxiety will also be examined as secondary objectives, such as pulse, blood pressure and cortisol blood levels.

Types of studies

This review will consider experimental study designs, including randomized controlled trials, non-randomized controlled trials, and quasi-experimental, before and after studies for inclusion.

Search strategy

The search strategy aims to identify published and unpublished studies. A three-step search strategy will be used in this review. An initial limited search of MEDLINE and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases. Finally, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English and Japanese will be considered for inclusion in this review. Studies published from 1993 to 2015 will be considered for inclusion in this review. The reason for this date limit was that the earliest use of the word "aromatherapy" to the knowledge of the reviewers, was found in an English language book published in 1993.30 The initial search was conducted by two reviewers independently.

The databases to be searched include:

MEDLINE, CINAHL, EMBASE, PsycINFO, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi.

The search for unpublished studies will include:

Controlled Trials. gov.

Initial keywords to be used are as follows:

aromatherapy, anxiety, complementary and alternative therapy, colonoscopy, endoscopy, and essential oil.

Assessment of methodological quality

Titles, abstracts and full texts (if necessary) will be independently reviewed by the primary and secondary reviewers to determine if the studies fit the inclusion criteria of this systematic review. Thereafter, papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer.

Data extraction

Data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The extracted data will include specific details regarding the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Authors of primary studies will be contacted for missing information or for clarification of information.

Data synthesis

Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All of the results will be subject to double data entry. Effect sizes expressed as odds ratios (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be statistically assessed using the standard chi-square test. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate. We will also consider sub-group analysis if potential confounders, such as age or use of sedation, can be stratified.

Conflicts of interest

The authors have no conflict of interest to declare.

Acknowledgements

None.

References