An abridged version of this article was published in the May 2019 issue of Medical Observer.
Printed edition:
Tam M. Does it pass the sniff test? Medical Observer. 2019 May 9. pp. 40-41. (PDF)
Online version on AusDoc.Plus platform:
“Can inhaling ‘alco-wipes’ ease acute nausea?”
Clinical scenario
In a discussion of GP tips and tricks on an online GP discussion board, a several members enthusiastically supported the use of nasal inhalation of “alcowipes” (sterile isopropyl alcohol pads) for the relief of acute nausea. If effective, this seems a novel and practical intervention in general practice. So, what is the evidence, especially for conditions presenting with acute nausea and vomiting commonly seen in general practice (e.g., acute gastroenteritis)?
Clinical question
What is the effectiveness of nasal inhalation of isopropyl alcohol as treatment of acute nausea in otherwise well ambulatory adults?
What does the research evidence say?
Step 1: The Cochrane Library
There is a Cochrane systematic review on aromatherapy for the treatment of postoperative nausea and vomiting (PONV), and this included studies of isopropyl alcohol [1]. Isopropyl alcohol did seem effective in this context. However, it could be argued that therapies for PONV shouldn’t be assumed generalisable to community GP settings.
Step 2: TripDatabase
I conducted a search using the TripDatabase PICO search tool (Participant: “nausea”, Intervention: “isopropyl alcohol”, Comparator: “placebo”, Outcomes: blank). Along with a rather useful evidence synopsis from the Alberta College of Family Physicians, there were two important clinical trials undertaken in the emergency department (ED) setting. April et al. (2018) compared isopropyl alcohol with ondansetron [2], and Beadle et al. (2016) compared isopropyl alcohol to placebo [3].
I’ll examine Beadle et al. (2016) published in the Annals of Emergency Medicine in detail and will discuss some of the findings in April et al. (2018) in context.
Critical appraisal
I will use the randomised controlled trial appraisal sheet from the Centre for Evidence Based Medicine [4].
PICO
Participants: who was studied?
84 adults (aged 18 to 65 years) presenting to the ED of the San Antonio Military Medical Center (an urban tertiary hospital serving active-duty military personnel, retirees, and beneficiaries) in the United States, presenting with a chief complaint of nausea or vomiting, rated at a level of at least 3 out of 10 on a verbally. The mean age was 34 years, 70% were female, the median nausea was 6 out of 10, with about a third of participants also having abdominal pain, a third with vomiting, and a sixth with diarrhoea.
Important exclusions: use of an antiemetic in the past 24 hours (including while in ED triage)
Intervention: what was the exposure?
intervention group: isopropyl alcohol medical preparation pad, held 2.5 cm from the nose, deep inhalations nasally for no more than 60 seconds, at 0 min, 2 min, and 4 min
If nausea was completely relieved, participants took no further inhalations. Rescue drugs could be used after 10 min from the start of the intervention.
Comparator: what was the control/alternative?
placebo group: sterile saline wipe, used in the same manner as the intervention
Outcomes: what was measured?
Primary outcome: self-rated nausea, by a verbal rating scale from 0 (labelled “no nausea”) to 10 (labelled “worst nausea imaginable”), at 10 minutes post-intervention
Secondary outcomes included: self-rated pain and satisfaction at 10 minutes, and subsequent rescue antiemetics use
Internal validity: are the trial results valid?
Randomised patient assignment?
Yes. The randomisation sequence was generated by computer and successive patients allocated by a “nonstudy individual”.
Groups similar at the start?
Yes. There were slightly more women in the placebo group (77% vs 62%) but they otherwise seemed very similar.
Groups treated equally apart from assigned treatment?
Probably, yes. This was a relatively short and simple intervention.
All patients accounted for?
Yes. Of the 84 patients screen and eligible, 80 were randomised and results from all 80 participants were analysed.
Measures objective? Or patients and clinicians kept blinded?
Probably, not. Self-reported nausea is likely a subjective measure. The study attempted to blind participants and investigators by obscuring the packaging of the commercial alcohol and saline pads with opaque brown tape. However, it is likely that participants would have noticed the difference in scent, and conceivable that the clinicians providing care will have as well. Adequacy of blinding was not measured in this study.
What were the results?
Primary outcomes – median (see Stat Facts) self-reported nausea scores (numerical score out of 10) at 10 min:
- isopropyl alcohol (3/10) vs placebo (6/10)
- effect size: -3, 95% confidence interval -4 to -2
- interpretation: substantial improvement in the isopropyl alcohol group compared to the placebo group
Secondary outcomes – receipt of antiemetic dose:
- isopropyl alcohol (89.2%) vs placebo (72.1%)
- effect size: 17.1%, 95% CI -0.5% to 34.8%
- interpretation: the isopropyl group received more rescue antiemetics than the placebo group, though this is in the context that most participants received rescue medication
Discussion and conclusion
Participants who used nasal inhalation of isopropyl alcohol seemed had a large and rapid improvement in nausea. However, this study does have significant limitations. The final measure is only 10 minutes after the intervention. As almost nine out of 10 participants took rescue antiemetics during the ED stay, the effectiveness of the intervention is unclear. It is doubtful that patients were blinded to the intervention and this can bias subjective outcomes.
April et al. (2018), which was by the same research group, provides some illumination [2]. They compared isopropyl alcohol to oral ondansetron 4 mg in the ED, with nausea measures up to 60 minutes. In this study, there was no indication that nausea returned in the isopropyl alcohol group. Rescue antiemetic use was much lower study-wide, which might have indicated a shift in prescribing culture. Of interest, the inhaled isopropyl alcohol group seemed to have more rapid and greater nausea reduction with less rescue antiemetic use than the ondansetron group.
My interpretation is that there is data from two reasonable randomised trials, albeit from the same researchers, that nasal inhalation of isopropyl alcohol provides clinically important relief from acute nausea, of at least a short duration, in community ambulatory patients. Considering the supportive evidence of the intervention in post-operative nausea and vomiting studies, it seems plausible, if not probable, that there is a real effect [1].
In the Australian general practice setting, isopropyl alcohol pads are plentiful and inexpensive. Nausea typically requires no specific treatment. However, where immediate antiemetics are indicated, inhalation of isopropyl alcohol in clinic appears to be an appropriate initial intervention.
Stat Facts
Measure of central tendency: means and medians
The arithmetic “mean” or average is the measure of central tendency that is most commonly used. However, means are poor or invalid description of central tendency when the variable is not smoothly continuous (e.g., the 0 to 10 nausea numerical rating scale) or the distribution of values is skewed. The “median” requires only that the variable can be ordered in ranks so requires less assumptions to be valid.
References
- Hines S, Steels E, Chang A, Gibbons K. Aromatherapy for treatment of postoperative nausea and vomiting. Cochrane database of systematic reviews 2018 Mar 10;3:CD007598.
- April MD, Oliver JJ, Davis WT, et al. Aromatherapy Versus Oral Ondansetron for Antiemetic Therapy Among Adult Emergency Department Patients: A Randomized Controlled Trial. Ann Emerg Med 2018 Aug;72(2):184-93.
- Beadle KL, Helbling AR, Love SL, April MD, Hunter CJ. Isopropyl Alcohol Nasal Inhalation for Nausea in the Emergency Department: A Randomized Controlled Trial. Ann Emerg Med 2016 Jul;68(1):1-9 e1.
- Centre for Evidence-Based Medicine. Critical Appraisal tools. 2014 [cited 2015 2015 Dec 1]; Available from: http://www.cebm.net/critical-appraisal/
