Interpreting Blood Pressure Readings by Eight-Principle Diagnostic Standards
By Tina Chen and Wei-Yen (Jimmy) Chang, LAc, Dipl. Ac.
Whether approached by a seasoned long-term practitioner or someone just setting up practice, there are cases in which it is difficult to differentiate a patient's condition according to classic Eight-Principle theory.
When a patient presents with complex symptoms, it is not always easy to come up with a confident, simple diagnosis and herbal prescription. The patient may be taking one or more pharmaceuticals that complicate the clinical presentation, which makes it difficult to know which symptoms are true and which are side-effects of the drug(s). The patient also may not tell his or her entire history or list of complaints for one reason or another.
Conversely, the difficulty in reaching a diagnosis may occur because the patient describes too many symptoms, whether they are related to the chief complaint or not. In other cases, contradictory elements are in play, such as when a patient exhibits all excess signs but states that he or she suffers from chronic fatigue syndrome. The patient may feel cold, but have a pulse that is forceful and rapid, and a tongue that is extremely red, with a definite yellow coating. One way or another, subjective complaints from patients may not always point to an immediate correct diagnosis.
One objective way to find out exactly whether the patient is truly suffering from deficiency, excess, heat or cold is to take the blood pressure and note the heart rate. Master Chang uses this method daily on all of his patients and has confirmed its practical usefulness through thousands of cases in 20 years of practice. Below is a brief summary of the patterns representing the most commonly seen complex types in the clinic.
Patients with both high blood pressure and a fast heart rate are, without exception, suffering from an excess heat condition. Please note that these patients may complain that they are tired and depressed. However, if they have high blood pressure and a fast heart rate, tonic herbs should never be used, despite the fact that the patient complains of tiredness. The diagnosis is excess fire. This should be addressed with heat-clearing herbs.
Type 2: Systolic pressure (low) + Diastolic pressure (low) + Heart rate (slow) = Yang Deficiency
Patients who have low blood pressure and a slow heart rate are experiencing deficiency, mostly qi or yang deficiency. These deficiencies are best helped by tonic herbs; never give these patients sedating herbs.
Patients who belong to this category usually suffer from blood stasis, which may be the result of an old injury or surgery. The heart rate is slow because of blood stasis/obstruction of the blood flow. In turn, systolic pressure is increased, as the body attempts to maintain balance. The increased pressure and lack of flow result in heat from deficiency. Carefully selecting appropriate blood-moving and stasis-resolving herbs with herbs to clear deficiency heat will be the most helpful strategy for treating these patients.
The last group might appear to reflect heat because of the rapid rate, but the low blood pressure tells a different story: the insufficient quantities of blood and yin in circulation require a rapid heart rate to maintain positive circulation. This is similar to a car engine running with insufficient oil: eventually, heat begins to build up from the deficiency of lubricating yin. These patients are suffering from yin deficiency heat, and must be treated with herbs that tonify yin and sedate the deficiency heat.
Summary: Using Blood Pressure + Heart Rate for Eight-Principle Differentiation
This approach can provide a guideline to follow when confronted with a confusing presentation in the patient. Tongue and pulse diagnoses should be combined with this approach to reach an accurate diagnostic conclusion. Here is an example of a recent case that was addressed using this method.
A 45-year-old female stated that she suffered from chronic fatigue syndrome, was extremely tired, and had no energy even for driving or simple activities. She complained of how stressful life is, how depressed she feels, and that everything in life is "just not right."
Tonic herbs might be the first approach that comes to mind, but the objective findings of her blood pressure (170/120) and heart rate (110 beats per minute) recommend otherwise. It is important to look at the tongue and take the pulse to arrive at an accurate diagnosis. If the tongue is red and the pulse rapid, then the patient's complaint of tiredness and fatigue can be ruled out. In this particular case, it would be important to avoid using a warming, drying tonic formula like bu zhong yi qi tang. Heat-clearing formulas like chai hu shu gan tang or long dan xie gan tang would appropriately provide sedation for this patient. Although it seems wrong on the surface of things to use a sedating formula for someone identifying herself as having chronic fatigue syndrome, this would be the correct and effective approach.
For further details on this approach, please contact the authors.
Tina Chen is the sister of John Chen, the regular "Herbs and Herbalism" columnist for Acupuncture Today. Tina graduated from South Baylo University and the University of California at Irvine, and received extensive postgraduate training at Anhui Hospital, First Tienjin Hospital and Guananmen Hospital in the People's Republic of China. She is a licensed acupuncturist and is certified by the World Health Organization in traditional Chinese medicine, with specialties in herbology and internal medicine. She is currently a professor of Chinese herbology at South Baylo.