Letter to the Editor Regarding ‘Effect of Inhaled Aromatherapy on Sleep Quality in Critically Ill Patients: A Systematic Review and Network Meta‐Analysis’

In recent years, inhaled aromatherapy has gained increasing attention in critical care medicine as a complementary treatment approach, due to its potential benefits in improving sleep quality and alleviating anxiety and stress in critically ill patients (Yap et al. 2019). We read with great interest the recent article published in the Journal of Clinical Nursing, which quantitatively assessed the effects of different essential oils on sleep quality in critically ill patients (Fang et al. 2024). We believe this study is of great significance in exploring nonpharmacological interventions in critical care settings. The study demonstrated for the first time that a combination of lavender, Matricaria recutita and neroli essential oils significantly improved sleep quality, outperforming the use of individual essential oils. The findings suggest that inhaled aromatherapy is a cost-effective, non-invasive and relatively safe intervention, offering considerable clinical value. It provides a novel nonpharmacological approach to critical care that may enhance overall prognosis and quality of life for critically ill patients. Additionally, this research establishes foundational data for future high-quality, large-scale randomised controlled trials to further validate the efficacy and safety of inhaled aromatherapy. Therefore, this study makes a significant contribution to critical care medicine and nonpharmacological interventions, expanding the scope of sleep management for critically ill patients and providing new therapeutic options. While this article provides a comprehensive evaluation of the potential benefits of inhaled aromatherapy for improving sleep quality in critically ill patients, there are significant limitations. First, the overall quality of the evidence is low, largely due to the limited number of included studies, small sample sizes and differences in study design and methodology. Additionally, most of the interventions were conducted over short periods (only 1 to 3 nights), which is insufficient to assess the long-term effects of aromatherapy. The article references Kang's work, but we noted that, in that study, inhaled aromatherapy was not found to be the best approach for improving sleep—massage was equally effective (Kang et al. 2023). This raises questions about the relative advantages of aromatherapy as suggested in this study. In terms of the mechanisms of inhalation aromatherapy, recent research has made some progress. For instance, the essential oil of Scutellaria nuristanica (SNEO) has been shown to have various biomedical applications, including anti-inflammatory, antioxidant, antimicrobial and analgesic properties, which may be mediated by the synergistic actions of multiple active components. The study revealed that the main constituents of SNEO, such as 24-norursa-3,12-diene, 3-oxomanoyl oxide, and β-eudesmol, exhibit significant activity in inflammation inhibition and pain relief, suggesting that aromatherapy may influence sleep quality through the modulation of neurotransmitters and inflammatory mediators (Shah et al. 2024). These mechanistic studies provide new insights into the role of aromatherapy in critical care and lay a theoretical foundation for future basic research. Moreover, the study lacks sufficient discussion on the potential side effects and safety of aromatherapy. While aromatherapy is generally considered non-invasive and relatively safe, potential risks such as allergic reactions, headaches and nausea need to be more thoroughly assessed. Furthermore, the study population was mainly limited to specific types of critically ill patients (e.g., those with coronary heart disease or postsurgical patients), limiting the generalisability of the results. Additionally, variations in the types of essential oils used, their concentrations, methods of inhalation and intervention durations across different trials contribute to the heterogeneity of the findings. To better validate the efficacy and safety of aromatherapy, future research should involve more high-quality, rigorously designed, large-scale randomised controlled trials, and explore the optimal methods and contexts for its use. He Sui: writing – original draft preparation. Dan Wang: writing – reviewing and editing. Zhi-Qi Zhang: conceptualisation. Yi-Xuan Guo: conceptualisation. Hai-Yan Zhang: supervision. The authors declare no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.