It can further affect patient satisfaction and leads  to hematoma ,dehydration, electrolyte imbalance, bleeding, complications of surgical sites, wounds, aspiration in postoperative patients

Commonly used older, traditional antiemetics for PONV include the anticholinergics (scopolamine), phenothiazines (promethazine), antihistamines (diphenhydramine), butyrophenones (droperidol) and benzamides (metoclopramide). These antiemetics have adverse effects such as dry mouth, sedation, hypotension, extrapyramidal symptoms, dystonic effects and restlessness.

The newest class of antiemetics used for the prevention and treatment of PONV are the serotonin receptor antagonists (ondansetron, granisetron). These antiemetics do not have the adverse effects of the older, traditional antiemetics. Headache and dizziness are the main adverse effects of the serotonin receptor antagonists in the dosages used for PONV.

This has lead to the emergence of interest in therapies which have advantage of low cost, limited side-effects and patient acceptability . The above beign pharmacological/ non-pharmacological therapies like hypnosis , relaxation imagery, music therapy aromatherapy, acupressure (Apr) , P6 point stimulation with acupuncture(Apu) /acupressure, ginger, chewing gum and others. 

Among the above mentioned therapies chewing gum and acupressure have been attracting attention,  because of patient acceptability and lower side effects   but still there are very less studies done on them and no comparison has been done between the two.

Chewing gum, p6 point acupressure is   believed to have a  potential as a novel , drug free alternative treatment for PONV, therefore we aim to conduct a randomised comparative study to evaluate the safety and efficacy of preoperative chewing gum , pericardial p6 point acupressure as an adjuvant  for attenuation of post op nausea and vomiting. 

If it is noted that chewing gum or pericardial p6 point is effective and its efficacy is comparable to the other pharmacological drugs, this study will be of benefit to millions of patients around world.

Sample size

Primary Outcome = Comparison of Post-Operative Incidence of Nausea and Vomiting 

 For estimation of sample size, the following formula has been used

n =     [z1-α/2.√2P(1-P) + z1-β.√{P1(1-P1) + P2(1-P2)}]2

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                                 (P1-P2)2                                                                       

where

Zα/2 is the critical value of the Normal distribution at α/2 (for a confidence level of 95%, α is 0.05 and the critical value is 1.96)

Zβ is the critical value of the Normal distribution at β (for a power of 80%, β is 0.2 and the critical value is 0.842)

p1 and p2 are the expected sample proportions of the two groups.

Assumptions:

The sample size calculated was 62 patients per group depending upon 20% reduction in postoperative nausea and vomiting as clinically significant difference and α error of 5%.