Perioperative acupuncture modulation: more than anaesthesia

This review article presents a comprehensive analysis of the role of acupuncture in perioperative medicine, demonstrating that its benefits extend far beyond the traditional scope of anesthesia. The authors propose the term "Perioperative Acupuncture Modulation" to better describe this broad range of therapeutic effects. The history of perioperative acupuncture dates back to 1958, when the first tonsillectomy was performed under acupuncture at the Shanghai People's Hospital. Initially called "Acupuncture Anesthesia," it was soon realized that the technique did not provide adequate anesthesia by itself but rather significantly reduced the need for conventional anesthetics and analgesics.

The review examines three main categories of benefit: reduction of anesthetic and analgesic consumption, reduction of anesthesia-related complications, and organ protection in the perioperative period. Regarding inhaled anesthetics, studies have shown reductions of 8.5%-11% in desflurane consumption in healthy volunteers. For opioids, acupuncture has shown the ability to reduce remifentanil consumption by up to 39% in minor surgeries. In major cardiac procedures, only 13% of the total fentanyl dose was needed in the acupuncture group compared with the control group.

The sedative effect of acupuncture also allows reduction in the use of hypnotics, with decreases of up to 27% in propofol consumption. Regarding postoperative complications, the P-6 (Neiguan) point emerged as the most studied for prevention of postoperative nausea and vomiting (PONV). Meta-analyses have confirmed its efficacy for both prevention and treatment, being more effective against nausea than vomiting. Acupuncture has also demonstrated modulatory effects on hemodynamic stability, both preventing hypotension and hypertension depending on the technique used.

Other complications such as post-intubation sore throat have also shown a significant reduction (14% versus 29.8% in the control group). The organ-protective effect represents one of the most promising aspects of perioperative acupuncture. For the heart, studies have shown reduced troponin I levels and shorter ICU stay after cardiac valve surgery. Pulmonary protection includes improvement in forced vital capacity after thoracic surgery.

In the brain, acupuncture has reduced biomarkers of neuronal injury (NSE and S100β) and accelerated recovery of consciousness by up to 35.86%. Liver and kidneys have also benefited through increased blood flow and reduced oxidative stress. Optimization of the technique involves appropriate selection of acupoints, with ST-36, SP-6, LI-4, and P-6 being the most commonly used. Point specificity is crucial — inappropriate points can lead to negative or opposite results.

Stimulation techniques vary between invasive and non-invasive, with electroacupuncture offering greater standardization. Different frequencies produce distinct effects: low frequency (2-4 Hz) for long-lasting analgesia, high frequency (50 Hz) for rapid but brief effects. The timing of stimulation is critical, with evidence suggesting that initiation before anesthetic induction is essential for maximum efficacy. Studies that initiated acupuncture after induction showed reduced or absent efficacy.

Future perspectives include application in special populations such as older adults and "triple-low" patients (low MAC, low blood pressure, low BIS), groups at higher risk of perioperative morbidity. Perioperative acupuncture aligns perfectly with enhanced recovery after surgery (ERAS) programs, offering opioid reduction, lower incidence of adverse effects, and reduced costs. Limitations include the need for trained professionals and standardization of protocols. Technological developments such as automated devices may facilitate clinical implementation.

Understanding of the mechanisms through functional neuroimaging (fMRI, PET) continues to evolve, revealing different patterns of brain activation depending on the stimulation technique used.