ACUPUNCTURE
Mechanism and General Practice
Increasing evidence supports the use of acupuncture, particularly
in areas of relevance to anesthesia. In 1998, a National Institutes of Health (NIH)
Consensus Panel reported that acupuncture showed promise in reducing postoperative
and chemotherapy-related nausea and postoperative dental pain.[122]
Acupuncture is the stimulation of anatomic locations on the skin
by a variety of techniques that can be classified as invasive (e.g., needles, injections)
or noninvasive (e.g., transcutaneous electrical stimulation, pressure, laser). Needles
inserted into the skin can be stimulated by manual manipulation, moxibustion (i.e.,
burning a substance to produce heat), pressure, laser, and electricity. There are
Chinese, Japanese, Korean, French, and other acupuncture systems for identifying
acupuncture points, but there is little research comparing these different systems.
As a result, there are no standard or optimal acupuncture points. Practitioners
consider acupuncture an art as much as a science.
The traditional theory of acupuncture is that it corrects disruptions
in the flow of energy (i.e., qi) and restores the balance of dual forces (i.e., ying-yang)
in the body. Data suggest that there is a scientific basis for acupuncture. Acupuncture
stimulates high-threshold, small-diameter nerves leading to activation of spinal
cord, brainstem (i.e., periaqueductal gray area), and hypothalamic (i.e., arcuate)
neurons, which trigger endogenous opioid mechanisms.[123]
The effect of acupuncture analgesia can be reversed by naloxone.[124]
Functional magnetic resonance imaging[125]
[126]
and positron emission tomography[127]
[128]
have demonstrated that acupuncture stimulation produces identifiable effects in the
human brain. Other mechanisms such as modulation of immune function,[129]
inhibition of the inflammatory response,[130]
regulation
of neuropeptide gene expression,[131]
and alterations
in hormonal levels[132]
have been proposed.
Although many clinical acupuncture studies have been published,
many are of poor quality, suffering from insufficient sample sizes, high dropout
rates, inadequate follow-up, and poorly defined illnesses, enrollment criteria, and
outcome measures.[123]
Acupuncture studies suffer
from inherent methodologic difficulties that include difficulties blinding patients
and acupuncturists, using placebo or sham acupuncture, and choosing between different
acupuncture techniques. One of the most promising indications for acupuncture is
to prevent postoperative nausea and vomiting (PONV).
