Acupuncture anaesthesia is a recent and purely Chinese invention. The Thoughts of Chairman Mao state that ‘Chinese medicine and pharmacology are a great treasure house and efforts should be made to explore them and raise them to a higher level.’ This was a very important impetus to the development of this application of acupuncture.
The Chinese look upon acupuncture anaesthesia as a useful working method for local or regional anaesthesia. They do not consider their methods of acupuncture anaesthesia to be perfect, but they look upon it as a subject that is being evaluated and developed all the time. The majority of operative procedures in Chinese hospitals are done with local or regional anaesthetics, and acupuncture anaesthesia is probably the commonest form of regional anaesthetic in use. Most hospitals that we visited seemed to be using acupuncture anaesthesia for between 40 % and 60 % of their surgical procedures.
The use of acupuncture anaesthesia is not confined to minor operations but includes major abdominal and cardio-thoracic surgery. During our visit to China we saw more than forty operations with acupuncture as the anaesthetic. There is no doubt that it was effective in a wide variety of operations. The Chinese often give figures of about 90% success rate, but our impression was that it was an acceptable form of anaesthesia for nearly all the operations we saw.
The clinical advantages of acupuncture anaesthesia are obvious. It is a safe and considerably less dangerous procedure than general anaesthesia, it is safer for the old and disabled, postoperative recovery is far swifter, it is a very cheap and simple form of anaesthesia, and the physiological functions of the body, such as the pulse rate and blood pressure, remain consistently stable during anaesthesia. The main disadvantage is that very occasionally the anaesthetic does not work and an alternative form of anaesthesia may be required fairly swiftly.
The possibility that a small number of patients might experience some pain is probably unacceptable in the context of a Western medical system. Furthermore, there is no muscle relaxation in acupuncture anaesthesia so it can be quite hard work to retract the abdominal muscles. Also, the Chinese have not found a solution to the discomfort that is occasionally caused by traction on the visceral contents.
Before acupuncture anaesthesia the Chinese explain to the patients what is going to happen. Most people, including the Chinese, are very frightened before going into an operating theatre, especially if they are going to be awake. It is therefore important to have the confidence of the patient before embarking on any type of surgery involving local anaesthesia. A premedication of barbiturates is usually given and the patient is wheeled to theatre. Body and ear points are selected on the same basis as for therapy and these are then stimulated electrically. In general low frequencies are used on the ear points and on distal body points (5-300Hz), and high frequencies are used on local points (3,000-l0,000Hz). When using the body points deqi is obtained first. When using ear points the Chinese insert the needle obliquely to be sure of hitting the point, and tape the needle in. Ear points will not be painful because there is not usually any local pain pre-operatively.
A period of induction is required whether ear or body points are used, and this is usually about twenty minutes. After inserting the needles the electrical stimulator is connected, set at the required frequency and maximum tolerable intensity, and left on throughout the operation. After the induction period anaesthesia should be adequate for the operation. For particularly painful operative procedures, such as separating the periosteum from the bone, small amounts of local anaesthetic are sometimes used. Very occasionally intravenous narcotics may be given if the operation is prolonged or the procedure is painful.
Point selection for acupuncture anaesthesia follows exactly the same rules as acupuncture therapy. When selecting body points for a thyroidectomy use Hegu (LI 4) and Neiguan (P 6) as distal points, and Neck-Futu (LI 18) as a local point. The ear points for this operation would be Throat, Neck, Shenmen and Subcortex; Throat and Neck are local points and Shenmen and Subcortex are sedative points. It is obvious, therefore, that the principles of point selection follow the principles of point selection for therapy, i.e., when using body acupuncture select local and distal points and when using ear acupuncture select local representative points and add in sedative points.
Acupuncture anaesthesia is a fascinating application of acupuncture; perhaps, in the West, it could be used for postoperative analgesia rather than anaesthesia.
At present there is no unified theory that explains the complex mechanism of acupuncture, but there are many well substantiated physiological changes that do occur when this technique is applied. The Chinese are investing a large amount of research resources in the investigation of the physiology of acupuncture; they are not limited to the traditional approach but they do see that this is empirically useful and gives better results than simply needling tender areas. Contradictions can co-exist easily in the Chinese mind and so there is no real conflict between the traditional and the more scientific approach to acupuncture, and furthermore they see this combined approach as mutually beneficial.
Acupuncture points are well known to us in the West, studies by Melzack show that acupuncture points correlate very closely with trigger points1 and that the use of these trigger points, particularly for injection therapy, is a well recognized technique within Western medicine. These tender areas (acupuncture points) are frequently to be found on or near neuromuscular junctions. Further work by Becker also strongly suggests that acupuncture points have special electrical properties, and that the skin over acupuncture points is able to pass electrical current more easily than the surrounding areas of normal skin.2 As yet, however, there is no good anatomical or physiological basis for the theory of the channels; although a considerable amount of physiological investigation has been directed at attempting to prove the existence of channels.3
The fact that acupuncture works as an analgesic is quite clear; surgical analgesia in animals and in man follows the needling of specific acupuncture points, and sham needling of non-specific points does not produce analgesia.4 Furthermore, using the human model of dental pain, acupuncture can also be shown to be a specific and relatively powerful analgesic.5 However, there has been a distinct lack of good clinical trials on the effect of acupuncture as a therapy for chronic pain problems; the author has reviewed the studies that are available and suggested models that can be used for the clinical evaluation of acupuncture.6 Such clinical trials are essential if acupuncture is to progress as a therapeutic technique within the context of Western medicine.
When an acupuncture point is stimulated various neurological and neurohumoral changes occur in the body. In decerebrate cats, stimulation of the skin inhibits the passage of painful stimuli.7 Work on small animals also shows that stimulating a specific acupuncture point changes the nerve transmission in the painful area, the spinal cord and the thalamus.8 Furthermore, some of the detailed neurophysiological studies completed at the Shanghai Institute of Physiology suggests that there is a supraspinal centre that inhibits viscerosomatic reflexes and that this is stimulated via acupuncture points; there is considerable evidence which would support the mediation of painful stimuli at a thalamic level as being one of the important mechanisms through which acupuncture can have an effect.9
The gate theory of pain10 also goes some way to explain the mechanism of acupuncture in pain. All pain input enters the spinal cord via the substantia gelatinosa, pain impulses travelling along the small nerve fibres. The large myelenated nerve fibres have an inhibitory effect on pain, by closing the gate to pain at cordal level, within the substantia gelatinosa. If pain is not transmitted to the brain, no pain is perceived. Melzack has suggested that acupuncture stimulates large myelenated nerve fibres, thereby closing the gate to pain.11 However, there are a large number of problems with the gate theory of pain, particularly as it is used to explain the mechanism of acupuncture. It is probable that acupuncture does work partially through the gate control theory, although this cannot be seen as a complete explanation of its mechanism.
Endorphins, or naturally occurring morphine-like substances, have recently been found in a wide variety of body tissues. In people suffering from chronic pain the endorphin level in the fluid around the brain, the cerebrospinal fluid, is low. Acupuncture increases the endorphin level in various parts of the central nervous system and beta-endorphin can be shown to attenuate chronic pain.12 This analgesic effect can sometimes be blocked by naloxone, a morphine antagonist13 although other studies suggest that the analgesic effect of acupuncture cannot be reversed by naloxone. Therefore, although the endorphin theory is another very useful idea through which acupuncture can be shown to have an effect, it does not seem to explain the complete physiological mechanism of this therapeutic technique.
These two ideas, the gate control theory of pain and endorphins, are not mutually exclusive. They go some way towards explaining the possible mechanism of acupuncture in pain, but the clinical application of acupuncture is much wider than its use in pain, so these ideas leave a great deal unexplained.
During our course we had a considerable number of lectures on the physiological basis of acupuncture, and some interesting ideas were discussed. As well as having an analgesic effect acupuncture seems to have a sedative effect. Puncturing Zusanli (St 36) bilaterally causes the alpha rhythm in the brain to predominate, and its amplitude to increase. Acupuncture also has a regulatory and anti-shock effect, which has been clearly demonstrated by creating massive blood loss in dogs; the dogs receiving acupuncture show a significantly increased survival rate.14 Acupuncture also affects the immune system; needling increases the white cell count, raises the titres of all groups of immunoglobulins, increases the activity of the reticulo-endothelial system and raises the level of serum complement. The claims that acupuncture can affect the immune system have been made primarily by the Chinese, but the author has also conducted some preliminary research which would seem to confirm this hypothesis. Furthermore, acupuncture has been shown, quite clearly, to cause changes in many of the chemical messengers (neurotransmitters) within many different areas of the brain.15
This short summary of the available evidence strongly suggests that acupuncture is having a fundamental physiological effect on the human body. The reason for including this section is that the scientific investigation of acupuncture is an integral part of the modern Chinese approach to acupuncture; this brief review just summarizes some of the current ideas in this field and more detailed information, dealing with these and other concepts, is available in many Western scientific journals (particularly the journal Pain). The effect of acupuncture on the body is attracting a great deal of scientific interest, both in China and the West. The field is changing fast and progressively more of the empirical findings of the ancient Chinese are being scientifically validated.
1 Melzack et al, 1977, Pain, 3 (1977), page 3.
2 Becker et al, Transactions on Biomedical Engineering, (1975) page 533.
3 National Symposia of Acupuncture Moxibustion and Acupuncture Anaesthesia, Peking, 1979.
4 Teral (Doctoral thesis), Faculty of Medicine, Montpellier, (1975).
5 Chapman et al, Pain, 9 (1980), page 183.
6 Lewith et al, Pain, 16 (1983), page 111.
7 Hill et al, Experimental Brain Research, 9 (1969), page 284.
8 Niboyet et al, L’Anaesthesic par l’Acupuncture, Moulins-les Metz, France, (1973).
9 Eh Shen et al, Chinese Medical Journal, 1 (1975), page 431.
10 Melzack et al, Science, 150 (1965), page 197.
11 Melzack et al, Pain, 1 (1975), page 357.
12 Akil et al, Science, 201 (1978), page 463.
13 Pomeranz, Advances in Biomedical Psychopharmacology, 18, page 351.
14 Anon, 1974, Journal of Chinese Medicine, 2 (1974), page 261.
15 Han Jisheng, National Symposia of Acupuncture, Moxibustion and Acupuncture Anaesthesia. Peking, 1979, page 27.