Postoperative nausea and vomiting (PONV) are common adverse events following surgery and anaesthesia. The reported incidence is particularly high in patients undergoing laparoscopic surgery, ranging from 40-77%. PONV can be very distressing for patients and can result in unplanned readmission in ambulatory surgery. Antiemetics are only partially effective for both prophylaxis and treatment, can have adverse effects and in the case of the newer medications are expensive. The effectiveness of a number of complementary therapies in reducing the incidence of PONV continues to be investigated, given their relative ease of application, relatively low cost, lack of significant side effects, and patient interest and acceptability.
The objective of this review was to determine from the available evidence the most effective non-invasive complementary therapies for reducing the incidence and/or severity of postoperative nausea and vomiting in women undergoing abdominal laparoscopies.
A literature search was undertaken using: relevant health care databases (eg. AMED, CINAHL, MEDLINE/PubMed, Current Contents, Science Direct); databases of reports, theses, and conference papers (eg Dissertation Abstracts, Conference Papers Index, National Research Register [UK]); and major sources of evidence-based practice information (e.g. Cochrane Library, Agency for Healthcare Research Quality, and clinical trials databases or registers) between the years 1980 and 2007. In addition reference lists of relevant journal articles and selected web sites were checked.
Randomised controlled trials and quasi-experimental studies investigating the effects of non-invasive complementary interventions on postoperative nausea and/or vomiting, and the need for rescue medication following abdominal laparoscopic surgery in women were considered for inclusion in the review. Trials with only a 'no-treatment' control group were not included.
Data collection and analysis
Assessment of the eligibility of studies for inclusion in the review and the methodological quality of eligible studies, and data extraction from included studies were undertaken independently by two reviewers. Odds ratios and relative risks for dichotomous data and a weighted mean difference for continuous data were calculated with 95% confidence intervals. Where pooling of data was inappropriate, studies were considered separately and a narrative summary reported.
Twenty-one studies involving a total of 2286 participants were included in the review. Thirteen studies investigated the effect of four interventions on PONV following gynaecological laparoscopy: ginger, acupressure, guided imagery and music. Eight studies examined the effect of two interventions on PONV following laparoscopic cholecystectomy: stimulation of acupoints by various means and oral carbohydrate rich beverage.
Six trials with a total of 554 participants investigated the effectiveness of varying dosages of ginger powder (Zingiber officinale) following gynaecological laparoscopy. There is some limited evidence to support providing ginger in doses between 1g and 1.5g to prevent or reduce the level of nausea postoperatively and to reduce the need for rescue medication whereas there is currently no evidence to support either a lower or higher dosage, i.e. <1000mg or >1.5g. Ginger in this dosage range (1-1.5g) has not been demonstrated to be effective in preventing vomiting.
Four trials, with a total of 399 participants, investigated the effectiveness of acupressure as prophylactic treatment for PONV in patients undergoing laparoscopic gynaecological procedures; two using the P6 acupoint on the lower arm and two using the Korean K-K9 acupoint on the hand. There is evidence that stimulation of the K-K9 acupoint is effective, however the evidence for stimulating the P6 acupoint in this group of patients is equivocal. Six trials involving 719 participants investigated the effectiveness of stimulation of acupoints in patients undergoing laparoscopic cholecystectomy. There is some evidence to suggest that acupressure or acustimulation at P6 may be somewhat more effective in reducing nausea and vomiting following this surgical procedure for male and female patients. One study with 186 participants (male and female) assessed the application of capsaicin ointment to the Korean hand acupressure point K-D2. The treatment demonstrated efficacy in both the early (0-6h) and later periods (6-24h) for both the reduction of PONV and the need for rescue antiemetics.
In treating established PONV postoperatively there were two trials, with a total of 172 participants, examining one category of intervention - inhalation of isopropyl alcohol (IPA). These two trials focusing on laparoscopic gynaecological procedures produced strong evidence that the administration of IPA is much quicker in achieving a 50% reduction in the level of nausea than the antiemetic ondansetron; however there is no evidence that it reduces the need for rescue antiemetics. The remaining three trials, two investigating oral carbohydrate rich beverage and the other guided imagery and music, did not demonstrate that these interventions were effective.
There is sufficient evidence to suggest that several of the interventions assessed could play a role in a multimodal approach to minimise PONV following abdominal laparoscopic surgery, albeit requiring further research to confirm that promise. The two interventions of note are the use of the Korean Hand acupoints for prophylactic purposes, particularly acupressure applied to the acupoint K-K9, and the use of impregnated pads for the inhalation of 70% isopropyl alcohol to treat established nausea in females. There is also some evidence to suggest that acupressure or acustimulation at P6 may be effective in reducing nausea and vomiting in patients (females and males) having a laparoscopic cholecystectomy.