title: Aromatherapy for treatment of postoperative nausea and vomiting.
abstract: BACKGROUND
  Postoperative nausea and vomiting is a common and unpleasant phenomenon and current therapies are not always effective for all patients. Aromatherapy has been suggested as a possible addition to the available treatment strategies.
  
  
  OBJECTIVE
  This review sought to establish what effect the use of aromatherapy has on the severity and duration of established postoperative nausea and vomiting and whether aromatherapy can be used with safety and clinical effectiveness comparable to standard pharmacological treatments.
  
  
  METHODS
  We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3); MEDLINE; EMBASE; CINAHL; CAM on PubMed; Meditext; LILACS; and ISI Web of Science as well as grey literature sources and the reference lists of retrieved articles. We conducted database searches up to August 2011.
  
  
  METHODS
  We included all randomized controlled trials (RCTs) and controlled clinical trials (CCTs) where aromatherapy was used to treat postoperative nausea and vomiting. Interventions were all types of aromatherapy. Aromatherapy was defined as the inhalation of the vapours of any substance for the purposes of a therapeutic benefit. Primary outcomes were the severity and duration of postoperative nausea and vomiting. Secondary outcomes were adverse reactions, use of rescue anti-emetics and patient satisfaction with treatment.
  
  
  METHODS
  Two review authors assessed risk of bias in the included studies and extracted data. As all outcomes analysed were dichotomous, we used a fixed-effect model and calculated relative risk (RR) with associated 95% confidence interval (95% CI).
  
  
  RESULTS
  The nine included studies comprised six RCTs and three CCTs with a total of 402 participants. The mean age and range data for all participants were not reported for all studies. The method of randomization in four of the six included RCTs was explicitly stated and was adequate. Incomplete reporting of data affected the completeness of the analysis. Compared with placebo, isopropyl alcohol vapour inhalation was effective in reducing the proportion of participants requiring rescue anti-emetics (RR 0.30, 95% CI 0.09 to 1.00, P = 0.05). However, compared with standard anti-emetic treatment, isopropyl alcohol was not effective in reducing the proportion of participants requiring rescue anti-emetics (RR 0.66, 95% CI 0.39 to 1.13, P = 0.13) except when the data from a possibly confounded study were included (RR 0.66, 95% CI 0.45 to 0.98, P = 0.04). Where studies reported data on patient satisfaction with aromatherapy, there were no statistically significant differences between the groups (RR 1.12, 95% CI 0.62 to 2.03, P = 0.71).
  
  
  CONCLUSIONS
  Isopropyl alcohol was more effective than saline placebo for reducing postoperative nausea and vomiting but less effective than standard anti-emetic drugs. There is currently no reliable evidence for the use of peppermint oil.
authors.affiliation: Mater Nursing Research Centre, Queensland Centre for Evidence-Based Nursing &Midwifery, A Collaborating Centre of the JoannaBriggs Institute, South Brisbane, Australia. sonia.hines@mater.org.au.
authors.forename: Sonia
authors.initials: S
authors.lastname: Hines
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Steels
authors.forename: Anne
authors.initials: A
authors.lastname: Chang
authors.forename: Kristen
authors.initials: K
authors.lastname: Gibbons
mesh_terms: D019840:2-Propanol / Q000008:administration & dosage*; D000280:Administration, Inhalation; D000932:Antiemetics / Q000008:administration & dosage*; D019341:Aromatherapy / Q000379:methods*; D018849:Controlled Clinical Trials as Topic; D006801:Humans; D036142:Mentha piperita; D010938:Plant Oils / Q000008:administration & dosage*; D020250:Postoperative Nausea and Vomiting / Q000628:therapy*; D016879:Salvage Therapy / Q000379:methods
chemical_list: D000932:Antiemetics; D010938:Plant Oils; C015424:peppermint oil; D019840:2-Propanol