Postoperative nausea and vomiting (PONV) is encountered in 20-30% of patients undergoing
surgery. PONV is a costly medical condition in financial and emotional aspects by causing
serious complications like elongation of hospital stay, postoperative bleeding, aspiration
pneumonia and electrolyte imbalances. In high risk individuals and operations, it can be
encountered in up to 80% of patients. The risk factors for PONV development in adults are
female gender, previous PONV and/or motion sickness, non-smoking and younger age.
Additionally, it has been reported that some surgery types, especially, laparoscopic
cholecystectomy and gynecologic surgeries along with the anesthetic agent, the duration of
anesthesia and postoperative opioid use also have direct effects on PONV development.
According to the 4th consensus guidelines for the management of PONV updated in 2020, in
patients with one or more risk factors, a multimodal prophylaxis using a combination of at
least 2 of the following methods; 5-HT3 receptor antagonists, corticosteroids,
anti-histaminics, dopamine antagonists, propofol anesthesia, NK-1 receptor antagonists,
anti-cholinergics and acupuncture.
Following the declaration of acupuncture as an effective treatment option for PONV in 1999
NIH Consensus Conference, studies about this topic gained speed and many high quality
randomized controlled clinic studies were performed. In one of the most comprehensive reviews
published in 2015, it is stated that stimulation of P6 acupuncture point remarkably reduce
the risk of PONV development, significantly decrease the amount of postoperative anti-emetic
requirement, provide similar PONV prophylaxis with different pharmacoprophylactic agents
(metoclopramide, cyclizine, prochlorperazine, droperidol, ondansetron and dexamethasone) and
have similar post-operative anti-emetic requirement with pharmacologic agents. In the same
Cochrane analysis, it is clearly stated that studies enrolling groups of sham acupuncture for
P6 are redundant and would not go any further than duplicating the available well-established
information. In this aspect, the proposed study design is comparison between treatment
groups.
PONV has a multifactorial ethology. It has been postulated that it occurs as a result of
activation of emetic center in the brain stem by stimulation of various peripheral receptors
as well as central receptors including the chemoreceptor trigger zone in the postrema region.
Following activation, the response of emetic center for anti-emetic agents is rather weak and
consequently this complicates PONV treatment. Acupuncture is a kind of periphery sensory
stimulus and has modulatory effects on the emetic center in the brain stem via neuronal
pathways. This neural modulation is thought to be the result of communication between
cerebellum and insula. As a result of these mechanisms of action, performing acupuncture
before the induction of anesthesia provides more effective PONV prophylaxis.
Pharmacologic anti-emetic agents increase treatment costs as well as bear some adverse
effects. The clinical condition created by PONV and increasing dissatisfaction due to the
adverse effects of the pharmacologic agents urge both patients and clinicians pursuing
non-pharmacologic modalities with proven efficiency, like acupuncture.
Therefore, it is essential to develop a standard, simple, effective prophylaxis protocol with
high patient compliance and without ad verse effects, especially in patients with high risk
for PONV. In the literature various different technique and materials were used for
acupuncture stimulation. Unfortunately, a standard is not present for the metal of the
needle, the length of the needle, the depth of immersion, the technique of stimulation and in
most of the studies these features are not specified at all. Meanwhile, although P6 is the
most studied point for PONV, there are encouraging evidence that some other points, like ST36
or LI4, might be incorporated into the PONV protocol. ST36 have potential effects in
balancing gastrointestinal motility by modulating gastric motility via vagovagal and
sympathetic reflex arches. Moreover, P6 in combination with ST36 has been successful in
treatment of hiccups, recently.
