Surgery as a remedy for body ailments dates back to ancient times. But it has only been within the past 150 years that general anesthesia has been on the scene.¹ The use of anesthesia has become a double-edged sword for the medical profession, contributing to a perplexing problem known as PONV, or post-operative nausea and vomiting. Although several factors may contribute to PONV, anesthesia is a major player and its effects on the patient continue to thwart attempts for a pharmacologic panacea. Aside from the unpleasant experience for the patient, PONV can complicate post-surgery recovery and further compromise the patient’s health.

The failure of antiemetic drugs to eradicate this problem, along with their unpleasant side effects, has led to a search for alternative therapies as a non-pharmacologic remedy. According to the results of recent studies, the time-honored practice of acupressure may just be the “miracle” cure. Acupressure is safe and economical, has none of the side effects of antiemetic drugs and is rapidly gaining acceptance as a scientifically proven inhibitor of PONV.

PONV Factors

That queasy feeling and the urge to purge are defensive maneuvers on the part of the body to rid itself of toxins or to find its balance. The degree to which one is susceptible to PONV depends on several variables, pre- and post-operative, as well as related to the surgery procedure itself.

Pre-operative factors:

• Age – Adults 55 years of age and older and children are less likely to experience PONV.
• Gender – Females are more susceptible, especially between puberty and menopause.
• Weight – Obesity prolongs the time needed to clear the body of toxins.
• Hormones – In the menstrual cycle, women close to their menses are at increased risk.
• Gastric contents – Food in the stomach increases the risk of anesthesia-related PONV.
• Previous PONV – Predisposition is set, and related anxiety may lead to excessive air swallowing and a resultant distended gastrointestinal tract.
• Motion sickness – Especially with the use of analgesia and opioids, vestibular sensitivity is affected.

Intra-operative factors:

• Type – Increased PONV is seen with laparoscopic, middle ear, ophthalmic and otolaryngology procedures.
• Duration – Longer operations require more anesthesia, increasing the time it takes for the body to clear the toxins.
• Anesthesia – General anesthesia has a 53 percent rate of PONV as compared to face-mask at 15 percent and regional blocks at 7 percent. Pre-medication with opioids also increases risk.

Post-operative Factors:

• Pain – A high association has been noted, with nausea subsiding as pain is relieved.
• Analgesia – Opioids are known to have an emetic effect.
• Movement – Movement may induce PONV, especially in patients prone to motion sickness.
• Hypotension – Blood loss, fluid restriction and the use of anesthesia and analgesics may lead to hypotension which can trigger nausea.²

While the personal experience of PONV is uncomfortable and annoying, the medical implications can be quite serious. The patient is at risk of complications such as “aspiration, dehydration, electrolyte disturbances and disruption of the incision site.”³ Additionally, a longer hospital stay may be required, increasing expenses and demands on hospital staff, and contributing to the patient’s anxiety over future procedures.⁴ With the ever-increasing costs of developing newer and better drugs to combat this problem and the added burden of dealing with subsequent side effects, acupressure has presented itself as a much simpler and more economical solution.

Proving the Point

In a systematic review of literature dating from 1980 to 1997, anesthesia researchers in Australia identified 19 randomized trials of non-pharmacologic techniques considered to be sound, scientific research and submitted them to meta-analysis. These studies were carefully screened for reliability, validity, randomization and blinding. All used treatment of the P6 acupuncture point (inner arm near the wrist), either by acupuncture, acupressure, electroacupuncture, transcutaneous electrical nerve stimulation or acupoint stimulation. Authors noted that these “diverse techniques stimulated the P6 acupuncture point and were considered as one entity, consistent with the concept that stimulating the right acupuncture point is more important than the nature of the stimulus.”⁵

In general, the authors concluded that in comparison to placebo, the non-pharmacologic techniques proved superior in preventing post-operative vomiting in adults, and were equal in comparison to antiemetic drugs. For those patients who shun the administration of drugs or may have an adverse reaction, the authors suggested that non-pharmacologic techniques may be beneficial, preventing PONV in 20 percent to 25 percent of adult cases.⁶

Acupressure has continued to hold its own as a viable alternative to drugs, as noted in more recent studies from Sweden and Ireland, published in 1999. These studies focused solely on the use of acupressure vs. placebo, utilizing the P6 point. Researchers determined that acupressure significantly decreased the incidence of PONV and that the response was not a placebo effect itself.^7,8

The incidence of PONV in laparoscopy procedures may be as high as 60 percent. In the Irish study, 104 laparoscopy patients undergoing investigation for infertility were randomly assigned to acupressure or placebo groups. Patients with obesity, diabetes mellitus and previous PONV – all high risk factors – had been excluded from the study. The women ranged in age from 19 to 43 years. Acupressure bands with beads placed at the P6 site were used for the treatment group. Bands were placed with pressure at a non-acupoint site in the placebo group, with neither patients nor nursing staff being aware of the allocation of treatment. An anesthetist, blinded to the treatment, rated the women for nausea, retching and vomiting at three designated points in time during a 24-hour, post-operative period. With risk factors being similar for the study subjects, the acupressure group scored significantly lower for nausea and vomiting than the placebo group (19 percent as compared to 42 percent.)⁹

The Swedish study was conducted on women receiving minor gynecological procedures in day surgery. In the double-blind study, 60 subjects were randomly assigned to one of three groups. “One group received acupressure with bilateral stimulation of P6, a second group received bilateral placebo stimulation and a third group received no acupressure wrist band and served as a reference group.”¹⁰ The subjects ranged in age from 18 to 62 years. Although this group was not carefully screened for risk factors as was the Irish group, there was a low incidence of previous PONV and motion sickness history. As in the previous study, authors were especially interested in evaluating, and had expected, a major placebo effect. Despite personal reports by patients in the placebo group of a decrease in nausea after 24 hours, there was no effect observed in the immediate 24-hour post-operative period. Only acupressure reduced the vomiting and need for antiemetic drugs within the initial 24-hour period and in comparison to the reference group, the reduction was significant.¹¹

Sham Sites

The use of placebo or sham sites has been considered a standard control in acupuncture research and often a point of contention. As regards analgesia, stimulation from the insertion of a needle “may have a counter-irritation effect which may have an effect on the gate control theory of pain.”¹² According to the authors of the Irish study, this does not apply to nausea and vomiting. And as corroboration, in their placebo acupressure group there was no evidence of immediate effect from the sham treatment.¹³

Another consideration in placebo effect is previous acupuncture or acupressure experience. Those patients accustomed to the procedure may be more predisposed to sensing the flow of chi and may also have expectations regarding the treatment. No mention was made in either acupressure study as to the study subjects’ previous experience. However, attempts were made to neutralize this possibility through various methods, such as bands being applied simultaneously with anesthesia administration and removed prior to emergence from the anesthesia.¹⁴

Why Not With Children?

The results of studies using acupressure to prevent PONV in adults have been impressive. But the same non-pharmacologic approach with children has been overwhelmingly inconclusive. In five major studies conducted between 1991 and 1999, acupressure and/or acupuncture was not effective in preventing PONV in pediatric cases.^15,16

A 1999 study conducted at Children’s Hospital in Boston involved children ages 2 to 12 undergoing tonsillectomy (known PONV risk incidence of 40 percent to 70 percent.)¹⁷ Two acupressure bands were applied prior to administration of drugs, one at the P6 site and another at a sham site. In the study group of 47 patients, a bead was used at the P6 site and removed from the site after administration of anesthesia. Acupuncture needles were then substituted for the bead prior to the administration of pain medication. In the control group of 53 patients, the same procedure was administered, but without the beads or needles. There was no significant difference in response between the two groups. “Retching occurred in 26 percent of the study patients and 28 percent of the placebo patients; 51 percent and 55 percent, respectively, vomited; and 60 percent and 59 percent, respectively, did either.”¹⁸

In conclusion, the authors of the study suggested modifications of this approach in future research with the hope of improved results. But the question is, if the P6 site worked so well for adults, why did it not work as readily for children? Jeff Silver, a holistic health practitioner in California who specializes in pediatrics, emphasized the need to consider the root of the nausea. “I would be inclined to look at the liver and digestive system because anesthesia is a toxin in the liver. In this situation, you may need to use more liver points. And there are a number of points we use in children that we don’t use in adults. I wouldn’t do just one point.”

There is also the question of the child’s energy system development. According to Silver, it is known in Traditional Chinese Medicine that a child’s meridian channels are not fully developed until age 7 to 8. “But (in) the big points, the chi is there,” said Silver. He has used P6 to effectively treat nausea in children, but has also made use of other points and techniques. “This is the difficulty with Western research,” he said. “Chinese medicine is holistic.” In other words, in identifying just one point to validate acupressure’s use in PONV, the holistic entity is removed from the treatment. It no longer encompasses all, including the individuality of the patient’s own energy system.

This concept is reinforced by Carol Elliott, an instructor at Pacific College of Oriental Medicine. “Chinese medicine is dynamic and you can’t make everything fit everybody. You have to find out where it will work. You have to juggle and work with it and assemble it to fit the patient,” said Elliott. “If P6 doesn’t work, it doesn’t mean nothing will,” she added.

In the general population, and specifically with gynecological surgery and laparoscopy procedure patients, acupressure at P6 has been shown to be a viable alternative or supplement to antiemetic drugs. Clearly it doesn’t work for everyone in every age group, but the research conducted during this past decade serves as a firm springboard for further investigation. It’s a starting point.