New approaches to the effectiveness of inhalation aromatherapy in controlling painful conditions: A systematic review with meta-analysis.

OBJECTIVE: Gather scientific evidence on the application of inhalation aromatherapy for pain relief and estimate the effect measure of this practice on pain reduction. METHODS: Searches were performed in 2021 in the Pubmed, Scopus, Web of Science, Cochrane, Science direct, Lilacs, Scielo databases. We selected 44 articles demonstrating the effect of aromatherapy on different painful conditions, of which 17 were inserted in the meta-analysis. The risk of bias was assessed according to Cochrane methodology. RESULTS: In 35 (79.55%) studies was observed a significant reduction in pain, especially pain labor and postoperative pain. Through the meta-analysis, it was found that inhalation aromatherapy reduces by up to -1.73 points of the visual analog scale (VAS), indicating that this practice contributes to the reduction of pain perception in different painful conditions. In addition, the meta-analysis indicated that the time after inhalation, the type of oil used and the type of pain treated are important variables that interfere with the magnitude of the effect. These effects are attributed to the ability of essential oils to modulate nerve control centers and neurotransmission systems involved in pain control. CONCLUSION: From the gathering of articles on aromatherapy, it can be noted that aromatherapy appears to be helpful in alleviating acute pain, however there is an imminent need to improve aromatherapy studies to reduce the risk of bias and increase the power of its clinical evidence. PROSPERO: CRD42019121665.

Trait anxiety affects the orofacial nociceptive response in rats.

The aims of the present study were to assess the influence of: a) trait anxiety on orofacial pain; and b) orofacial pain on state anxiety. Forty-four rats were initially exposed to the free-exploratory paradigm for the evaluation of their anxiety profiles. In accordance to the parameter "Percentage of time in the novel side", the animals were considered as presenting high or low levels of trait anxiety when presenting values below the 1st quartile, or above the 3rd quartile, respectively. A week later, formalin-1.5% was injected into the upper lip of each animal. The behavioural nociceptive response, characterized by increased orofacial rubbing (OR), was quantified for 30 minutes, as follows: Total time OR (0-30 minutes: total pain), 1st phase OR (0-6 minutes: neurogenic pain), and 2nd phase OR (12-30 minutes: inflammatory pain). Immediately after this test, but still under the effect of formalin, the rats were submitted to the Elevated Plus-maze test (EPM). The results showed that the high trait anxiety individuals presented higher frequency of OR than the low trait anxiety ones, except during the neurogenic pain period. However, no correlation was found between OR frequency and levels of state anxiety presented on the EPM. In conclusion, the animals presenting higher anxiety profiles were the most susceptible to orofacial pain, nevertheless, orofacial pain did not influence state anxiety.

Trait anxiety affects the orofacial nociceptive response in rats

The aims of the present study were to assess the influence of: a) trait anxiety on orofacial pain; and b) orofacial pain on state anxiety. Forty-four rats were initially exposed to the free-exploratory paradigm for the evaluation of their anxiety profiles. In accordance to the parameter "Percentage of time in the novel side", the animals were considered as presenting high or low levels of trait anxiety when presenting values below the 1st quartile, or above the 3rd quartile, respectively. A week later, formalin-1.5% was injected into the upper lip of each animal. The behavioural nociceptive response, characterized by increased orofacial rubbing (OR), was quantified for 30 minutes, as follows: Total time OR (0-30 minutes: total pain), 1st phase OR (0-6 minutes: neurogenic pain), and 2nd phase OR (12-30 minutes: inflammatory pain). Immediately after this test, but still under the effect of formalin, the rats were submitted to the Elevated Plus-maze test (EPM). The results showed that the high trait anxiety individuals presented higher frequency of OR than the low trait anxiety ones, except during the neurogenic pain period. However, no correlation was found between OR frequency and levels of state anxiety presented on the EPM. In conclusion, the animals presenting higher anxiety profiles were the most susceptible to orofacial pain, nevertheless, orofacial pain did not influence state anxiety.