|24/10/2005 - Anesthesia May Weaken Acupuncture's Effectiveness |
new study using functional magnetic resonance imaging (fMRI) to
measure patients' pain levels, shows that anesthetics may diminish
the positive effects of acupuncture when used during surgery.
Results of the study
were presented here on October 22nd at the annual meeting of the
American Society of Anesthesiologists (ASA) Annual Meeting.
Acupuncture is an
ancient Chinese medical practice, which involves the insertion of
very fine needles into the skin to stimulate specific anatomic points
in the body called acupoints for therapeutic purposes by triggering
the releases of neurotransmitters that constrict blood vessels and
ultimately reduce pain.
also use heat, pressure, friction, suction, or impulses of electromagnetic
energy to stimulate the points.
Despite a lack of
scientific knowledge supporting acupuncture use, the technique is
often used as an alternative or adjunct treatment for a variety
of medical conditions.
According to lead
researcher Shu-Ming Wang, MD, Director, Pediatric Preadmission Program,
Associate Director, Pediatric Pain Mainagement, Department of Anesthesiology,
Yale School of Medicine, New Haven, Connecticut, acupuncture has
been shown to help relieve preoperative anxiety and postoperative
pain, nausea and vomiting, although there is a lack of consistency
in the technique's effectiveness.
Dr. Wang presented
the findings of a cross-over study, which used fMRI to measure central
nervous system changes in 10 patients with an average age of 28
years of age and no prior experience with acupuncture.
All subjects underwent
two experimental sessions that included 12 repetitive cycles of
manual acupuncture stimulation with each cycle consisting of 20
seconds on and 20 seconds off. The total stimulation process lasted
10 minutes while volunteers were awake and under propofol general
anesthesia. The acupuncture intervention was performed in just below
the head of the tibia, lateral to the tibia. General anesthesia
was induced and maintained to keep the Bispectral Index (BIS) at
30, using 2 mg/kg of IV propofol and continuous propofol infusion
The BIS value is
obtained using a modern neurophysiologic monitoring device that
to determines the patient's level of anaesthesia by continually
analyzes the patient's electroencephalogram (EEG) during general
anaesthesia. The BIS value ranges from 0 to 100. A BIS value of
0 equals EEG silence, 100 is the expected value in a fully awake
Dr. Wang said the
researchers found a significant difference between the awake and
general anesthesia states in activation patterns in the central
nervous system during acupuncture stimulation. They suggest that
this finding may explain some of the conflicting data regarding
the efficiency of acupuncture in the perioperative clinical setting.
studies are needed to determine whether these changes are caused
by anesthesia agents or by a change in consciousness, and how these
factors alter the effectiveness of acupuncture in the operative
setting," Dr. Wang said.
Usichenko TI, et al. Evid Based Complement Alternat Med. 2005 Jun;2(2):185-189.
Epub 2005 May 11.