Hunt 2013.
| Methods | 4‐group RCT comparing an aromatherapy blend (n = 74), ginger aromatherapy (n = 76), and IPA (n = 78), with a saline placebo (n = 73) | |
| Participants | 301 adult patients having surgical procedures. Inclusion criteria: "age 18 years or older, being cognitively able to give informed consent, having surgery that day, not receiving warfarin (Coumadin), heparin, full dose 325 mg aspirin, or clopidogrel (Plavix), and not having a history or diagnosis of bleeding diatheses or any known allergies to ginger, spearmint, peppermint, or cardamom. The exclusion of patients with clotting disorders was based on studies finding antiplatelet and cyclooxygenase‐ 1 enzymes inhibitors from constitutions of ginger." Setting: ambulatory surgical centre, USA |
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| Interventions | Comparison of normal saline, 70% IPA, essential oil of ginger, and a blend of the essential oils of ginger, spearmint, peppermint, and cardamom. "Each aromatherapy was stored in a plain white bottle labelled 1 to 4 and kept in a locked cart labelled “For Research Purposes Only.” "One millilitre of the randomly selected, designated aromatherapy was placed on a 2‐inch by 2‐inch [5 cm x 5 cm] impermeable, backed gauze pad. On complaint of nausea, participants were instructed to inhale the scent through the nose 3 times." | |
| Outcomes | Nausea severity at first complaint and 5 min as measured on a 4‐point Likert scale (0 = no nausea, 3 = severe) reported as percentage improvement in nausea scores, percentage requiring rescue antiemetics | |
| Notes | Additional information requested and promised but not yet supplied. No funding received | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Participants who responded with a [nausea] score of 1 to 3 were randomly assigned to 1 of the 4 treatment groups using a computerized listing for random assignments generated by Assumption College." Comment: likely done |
| Allocation concealment (selection bias) | High risk | "The research nurse checked off the study number of the participant and aromatherapy on the list and then prepared the gauze pad." Comment: probably not done. Allocator reported as preparing the intervention treatments |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | "Despite the lack of any identifying label, the study treatment arms could not be blinded because of the specificity of odours." Comment: probably not done |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | "Despite the lack of any identifying label, the study treatment arms could not be blinded because of the specificity of odours." Comment: probably not done |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | "...2 subjects were excluded from the protocol analysis because of what was believed to be a degradation of the blend of the aromatherapy
oils". "The ITT analysis population differed only for the blend group, and the ITT blend comparisons were virtually identical to those for the PP analysis for saline and alcohol (P < 0.001 for all 3 outcomes)." Comment: low attrition |
| Selective reporting (reporting bias) | Low risk | Comment: small range of outcomes, all reported. No protocol available |
| Other bias | Low risk | Comment: no other sources of bias apparent |