Postoperative nausea and vomiting (PONV) affect 20% to 30% of patients undergoing general surgery and up to 70% in risk groups — women, nonsmokers, patients with prior history of PONV or motion sickness, and surgeries with volatile anesthetics or opioids. Among non-pharmacologic interventions, stimulation of point PC6 is one of the longest investigated and the one with the largest body of evidence, synthesized and updated periodically in a Cochrane review.
PONV RISK \U2014 APFEL SCORE (FOUR CLASSICAL FACTORS)
PROPHYLACTIC ANTIEMETICS — GENERAL COMPARISON AMONG OPTIONS
| INTERVENTION | MECHANISM | TYPICAL SETTING |
|---|---|---|
| Ondansetron | 5-HT3 antagonist | first line in moderate/high risk |
| Dexamethasone | Glucocorticoid (central anti-inflammatory) | monotherapy or combined prophylaxis |
| Droperidol | Dopamine antagonist | prophylaxis (monitor QT) |
| Aprepitant | NK1 antagonist | prophylaxis in high risk / prolonged surgery |
| PC-6 (Neiguan) | Non-pharmacologic stimulation | adjuvant prophylaxis; refractory PONV |
What the Cochrane Says
The Cochrane systematic review on PC-6 stimulation for PONV prevention pooled dozens of randomized clinical trials and consistently identifies a reduction in the relative risk of postoperative nausea, postoperative vomiting, and need for rescue antiemetic compared with placebo (sham). The magnitude of effect is comparable to that of first-line antiemetics such as ondansetron in some head-to-head comparisons, and an additive effect is described when PC-6 stimulation is combined with standard pharmacologic prophylaxis.
NETWORK META-ANALYSIS — LEE ET AL., 2025 COCHRANE UPDATE
Plausible Mechanism
The PC6 point is located in territory innervated by the median nerve, with cutaneous and deep branches that ascend via spinothalamic pathways to the brainstem. Stimulation modulates the área postrema and the nucleus of the solitary tract — centers of the vomiting reflex — and appears to act via release of β-endorphins and activation of central serotonergic and dopaminergic antiemetic pathways. This mechanism explains the dose-dependent effect observed with different stimulation intensities.
Immediate preoperative
Apply acupressure (wristband) or TEAS over PC6 before induction; maintain through immediate recovery.
Multimodal combination
Additive effect with ondansetron/dexamethasone; useful in patients Apfel ≥ 3.
No anesthetic contraindication
Compatible with general anesthesia, regional anesthesia, and blocks; no pharmacologic interaction.
Acknowledged Limitations
Heterogeneity across studies is relevant: the timing of initiation of stimulation (pré-, intra-, or postoperative), duration, modality (needle vs. acupressure vs. TEAS), and type of anesthesia all vary. Some trials present moderate to high risk of bias, and patient blinding is particularly challenging for acupressure. Even só, the magnitude and consistency of the effect support the current recommendation.
Fonte Original
Cochrane Database of Systematic Reviews(em inglês)Founded in 1989 by physicians trained at the University of São Paulo (USP) and specialized in China, CEIMEC is a Brazilian national reference in the teaching and practice of medical acupuncture. With more than 3,000 physicians trained over 35 years, it collaborates with HC-FMUSP and is recognized by the Brazilian Medical College of Acupuncture (CMBA/AMB).
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