Investigating the Effect of Inhalation Aromatherapy with Lemon Essence on Nausea, Vomiting, Pain, and Delirium in Patients Undergoing Coronary Artery Bypass Graft Surgery

Determining the Effect of Inhalation Aromatherapy with Lemon Essence on Nausea, Vomiting, Pain, and Delirium in Patients Undergoing Coronary Artery Bypass Graft Surgery.

A randomized, controlled clinical trial with two parallel groups, triple-blind, phase 3, and a sample size of 104 participants. Block randomization with blocks of four will be performed using Excel software.

This phase III randomized triple-blind trial with 104 participants will be conducted at Baghiatallah medical centers to evaluate lemon aromatherapy’s effect on nausea, pain, and delirium after coronary bypass surgery. The intervention runs from the night before surgery to 24 hours after. Data will be collected via standard tools. Block randomization (blocks of four) and blinding of participants, researchers, assessors, and analysts will be used. Oils are coded by a third party.

Inclusion Criteria: Age 40–80 years, ASA class II or III, alert, without history of delirium or psychiatric disorders, no prior participation in similar studies, and scheduled for coronary artery bypass graft surgery. Exclusion Criteria: History of allergy to herbal products, presence of olfactory dysfunction

Intervention group: Five drops of 100% lemon essential oil (produced by Barij Essence Company) on cotton, placed 10 cm from the nose, administered every 4 hours from the night before surgery until 24 hours after, by a trained nurse blinded to group allocation. Control group: Five drops of odorless bitter almond essential oil (Barij Essence), with identical packaging, method of administration, intervals, and frequency, applied every 4 hours.

Nausea and Vomiting, Pain, and Delirium after Coronary Artery Bypass Graft Surgery

In this study, block randomization with blocks of four will be used. Random sequences will be generated using Microsoft Excel and its random function. Each allocation within the randomization sequence will receive a unique numerical code, and participants will be randomly assigned to either the intervention or control group. The treatment regimen corresponding to each random sequence will be placed in sealed envelopes labeled with the assigned code. These envelopes will then be placed in a box in random order. The assigned codes and corresponding treatment types will be recorded and maintained by the study epidemiologist, who will retain access to the randomization list.

In this study, triple-blinding will be implemented, meaning that the participants, the study investigator, the outcome assessor, and the data analyst will all remain unaware of the assigned intervention (aromatherapy with lemon essential oil or placebo). Given the distinctive scent of lemon essential oil, specific measures will be taken to maintain participant blinding. Upon enrollment, participants will be informed that they are taking part in a study investigating the effects of a plant-based aroma, without any reference to the specific type of essential oil (lemon or bitter almond). This information will be clearly stated in the informed consent form. In the control group, a scentless bitter almond essential oil will be used, matched identically with the lemon oil in terms of bottle appearance, volume, color, and method of administration. Both types of essential oils will be prepared in sealed, coded envelopes by an individual not involved in the research team and assigned based on a randomization table. Participants will be aware that they are receiving one of two plant-based aromas, but they will not know whether they belong to the intervention or control group. Furthermore, no notable or perceivable difference in olfactory experience is expected, as the placebo will be presented as a "herbal extract" without drawing attention to the study design, thereby preserving participant blinding. The investigator and outcome assessor will also be blinded to the type of intervention through the use of anonymous codes and a randomization schedule generated by an independent third party. Similarly, the data analyst will analyze encrypted files without access to group allocation details.

Only part of the data, such as information related to the main outcome or the like, can be shared.

Access period 6 months after results are published.

It will only be available to researchers working in academic and scientific institutions.

No special conditions are considered.

The person responsible for the study is Siavash Sangi. siavashsangi@gmail.com

After receiving the qualified applicant's email, the documents will be sent within a short period of time.