Treating PEOPLE, Not Symptoms!
Bio-Impedance
Montanaro Chiropractic
Treating PEOPLE, Not Symptoms
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Treating PEOPLE, Not Symptoms!
Bio-Impedance Treating PEOPLE, Not Symptoms
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BIA Doctor’s Interpretation Guide
What is Bio-Impedance Analysis?
As a clinician, would it be valuable for you to quantify your patient’s health, or, in the case of the critically ill, his/her survivability? Would it be helpful for you to be able to accurately measure the effectiveness of the Therapeutic Lifestyle Changes (TLC) that you have prescribed? Would you like to know if your patients’ recent weight loss is the result of the reduction of body fat, water, or lean tissue? Would you like to be able to do this in your office at a cost of less than one dollar per test?
Does this sound too good to be true? The answer is no, not if you are familiar with the science of bio-impedance analysis (BIA). BIA is a simple in-office test that converts easily obtained electrical measurements into information about the patient’s body composition (lean tissue, fat tissue and body water), fluid distribution (intracellular water versus extra cellular water) and a quantifiable value for tissue health or survivability.
Electrical measurements have been used as a gauge of hydration status since 1940. Over the last several decades, this science has evolved to a level of cost-effectiveness and reproducibility that BIA can be effectively used in any health care office. In 1996, the American Journal of Clinical Nutrition (64 (suppl): 489S – 497S) reported that “body composition can be estimated with simple and easily applied techniques,” (BIA), “and that the estimates are sufficiently precise for use in clinical investigation and practice.”
How is the BIA test performed?
1. Removable adhesive electrodes are attached to the extremities of the patient as shown in the diagram below. 2. Alligator clip leads are attached to the removable electrodes as shown. The red colored leads are always attached to the proximal lead. 3. The BIA instrument is turned on. Then, resistance and reactance values are measured and displayed as ohms. 4. The BIA software will calculate parameters related to body composition, fluid distribution, and tissue health based upon the patient’s resistance, reactance, height, weight, and sex.
What Values are measured? The BIA instrument measures whole body electrical resistance and capacitive reactance. These values, along with the patient’s height, weight and sex are used to approximate the patients’ body composition, fluid distribution and tissue health.
Electrical Resistance: Electrical resistance is defined as the opposition to current flow. The BIA instrument generates a constant 50 Khz current of 475 micro amps that flows through the patient. This approximates the current generated by a “nearly dead” AA battery. Electric current of this magnitude is not contra-indicated in patients who are pregnant, have organ transplants, and/or pacemakers. NOTE: If the patient has an artificial limb, it is advised that the examiner, if possible, utilize the side of the body opposite the prosthesis.
The measured electrical resistance is inversely proportional to total body water, and lean tissue (muscle).
Capacitive Reactance: A capacitor is an electrical component that can temporarily store an electrical charge. Cells in a biologic system can store an electrical charge as long as the cell membrane is intact. When the cell dies, the reactance value goes to zero. Therefore, it can be inferred that reactance is proportional to the health of the cell.
However, reactance values alone should not be used to compare the general health of different patients. Electrical current follows the path of least resistance. When a patient has low electrical resistance (due to high body water), he or she will generally have a lower reactance value because more of the current travels through the body water. Therefore, less current is available to store charge across the cell membrane. The values of phase angle and impedance index are derived from the combined values of resistance and reactance and provide the best numbers for comparative analysis.
How are the measured values converted into information about human physiology? This is the “magic” of the BIA software. Thousands of test patients were analyzed with both BIA and known methods of body composition assessment. The known methods were as follows:
1. DEXA, Dual Energy X-ray Absorptiometry, was used to assess Fat Free Mass (FFM). 2. K40 Isotope Dilutions were used to assess Body Cell Mass (BCM). 3. Dueterium Oxide (slightly radioactive water) was used to assess Total Body Water (TBW). 4. Sodium Bromide isotope dilution was utilized to assess Total Body extra-cellular Water (ECW).
First, thousands of data points were obtained from male and female patients of varying heights, weights, and ages. Then, a series of regression equations were derived to approximate body composition and fluid distribution from the measured values of electrical resistance and capacitive reactance.
What are the advantages of BIA?
This test is economical, reproducible, and very sensitive to changes in tissue and fluid status. The derived value, “phase angle”, has been published as the best indicator for prognosis of survival for patients with cancer, AIDS, and renal disease. (References are listed below). This value, or a companion value known as the impedance index, can be used to quantify the patient’s progress with higher values indicating improved health.
References: (Ott and Fischer, J of AIDS&RV Vol. 9 No. 1, 1995.)
What are the limitations of BIA?
BIA values are approximate values from derived equations. Therefore, patients who are very tall, very short, very thin, or very obese may have a greater degree of error than patients of average height and weight. However, it should be noted that this test is very consistent. Once a baseline has been established, even slight changes in these atypical patients can be accurately assessed with BIA.
The BIA software cannot be utilized for children under 10 years old. No equations have been established for this age group. However, experienced clinicians can effectively use the measured values of resistance and reactance to monitor progress of children – with or without the use of the software.
The water in body fat is calculated as extra-cellular water. Therefore, obesity appears to create an imbalance in intra-cellular and extra-cellular fluid. Although obesity is a major health risk, this increase in extra-cellular fluid is not and should not be associated with the transudation of fluid from the intracellular to the extra-cellular compartment.
There is a wide range of “normals” for phase angle within the population. Patients of smaller stature (i.e. petite females) may have a much lower phase angle than large males. The phase angle value is dependent upon both the number of cells, and the health of the cells. Therefore, two patients cannot be accurately compared to one another. Each person must serve as his/her own control for serial analysis.
BIA approximates physical values. The patient may have a serious health condition where the BIA values may have no significance. For example, a 33-year-old professional baseball pitcher recently died as the result of a sudden myocardial infarction. Athletic, lean, young patients typically have excellent BIA numbers. Therefore, these physical values cannot rule out the risk of heart attack, stroke, or even cancer. However, the BIA values – especially phase angle - are highly correlated with survivability from illness or injury.
What conclusions can be drawn from the BIA report?
BIA provides consistent reproducible data about body composition, fluid distribution, and tissue health / survivability.
Body Composition: The BIA report provides estimates of Body Cell Mass (BCM), Extra Cellular Tissue (ECT) and Body Fat.
Body Cell Mass: The BCM defines the mass of all metabolically active tissues, including muscle and organ tissues. These can metaphorically be referred to as the “engine” of the body where all work is done. These tissues consume oxygen, produce carbon dioxide, oxidize glucose, and synthesize proteins including enzymes.
In a typical adult, the organ mass should remain nearly constant. Minor declines may occur with advancing age. However, the muscle mass should remain constant or may even increase under optimal circumstances. In a three-year study on biomarkers of aging, Evans and Rosenberg of Tufts University concluded that muscle mass was the top biomarker of healthy aging. Their research is summarized in their book entitled BioMarkers.
The following quote from a 1997 edition of the journal Nutrition summarizes the significance of muscle mass as related to healthy aging: “. . . no decline with age is as dramatic or potentially more significant than the decline in lean body mass. In fact, there may be no single feature of age-related decline more striking than the decline in lean body mass in affecting ambulation, mobility, energy intake, overall nutrient intake and status, independence and breathing.”
J Nutr 127:990S-991S (1997)
Extra-Cellular Tissue (ECT): If the BCM is considered the engine of the body, then the ECT should be considered the chassis. The ECT consists primarily of ligaments, tendons, and bones and function in structural support and transport. The lean body mass of the patient is the sum of the BCM and the ECT.
Fat Mass: Fat Mass is the measure of total lipid mass within the body. This value is calculated by subtracting the lean body mass from the weight of the patient. Elevated fat mass and obesity are epidemic in America. The costs in healthcare are overwhelming, and the cost of human suffering is immeasurable. Consider these quotes about obesity.
“According to most recent statistics, over
97 million Americans (61 percent) are overweight, and this number is
increasing every year. Overweight is the most common type of altered body
composition and is associated with a high incidence of cardiovascular disease,
metabolic syndrome, hypertension and dyslipidemia. Data from the National
Institutes of Health (NIH) indicate that these conditions alone account for more
than $100 billion in health care expenses annually.”
Consider also information from the journal,
Health Affairs. “The study found that obesity -- linked to health
complications including diabetes, arthritis, heart disease, strokes and certain
cancers -- raises a person's healthcare costs by 36 percent and medication
costs by 77 percent.
Fluid Distribution:
Total Body Water (TBW): The total body water is the sum total of the fluid volume of the patient. TBW is further subdivided into Intra-Cellular Water (ICW) and Extra-Cellular Water (ECW). TBW is dependent upon the hydration status of the patient as well as body composition. Lean tissue is approximately 73 percent water whereas fat tissue is approximately 10 percent water.
Consider these quotes from the medical textbook Fluid, Electrolyte, and Acid-Base Balance: (Horne, Heitz, & Swearingen; MOSBY, 1991)
“Water is the primary constituent of the human body. All body fluids are dilute solutions of water and dissolved substances (solutes). The average 70 kg adult male is approximately 60% water by weight, while the average female is approximately 55% water by weight.” “The percentage of body weight that is water varies with such factors as age, gender, and body fat content.”
Intra-Cellular Water (ICW): The intra cellular water is the fluid volume within the cells of the body. The primary electrolytes of the intra-cellular fluid are potassium and magnesium. Generally an increase in intra-cellular water is associated with anabolic processes and improved health.
Under normal physiologic circumstances, changes in ICW occur gradually. However, athletes on or off anabolic steroids or patients starting or stopping corticosteroids like prednisone can experience substantial shifts in fluid volume in a relatively short period of time. It is worth noting that anabolic steroids will generally improve the BIA values but not necessarily improve the health and survivability of the patient. Corticosteroids generally cause fluid retention in the extra-cellular compartment and worsen the BIA values.
What is considered normal? Fluid, Electrolyte, and Acid-Base Balance (page 2) states: “Approximately two thirds of the body’s fluid is intracellular, equaling nearly 25 L in the average (70 kg) adult male. The remaining one third is extra-cellular, which is equal to approximately 12 L in the average (70 kg) adult male.”
Extra-Cellular Water (ECW): The extra-cellular water is the fluid volume located outside of the cells of the body and includes plasma and the interstitial fluids. The primary electrolyte of the extra-cellular fluid is sodium. Under optimal circumstances, one third of the body’s fluids should be extra-cellular.
NOTE: Water located within adipose tissue is calculated as extra-cellular water. Therefore, females who generally have higher levels of body fat will have ECW values that are approximately 5 percent higher than males of comparable health and hydration status.
Transudation of Body Fluids: Cell membranes are semi-permeable and will allow the transport of fluid and substances across the cell membrane. “Biomembranes are thin films consisting of proteins and lipids. They are not rigid or impermeable but, rather, are highly mobile and dynamic structures. Membranes are the gatekeepers of the cell. They control not only access of inorganic ions, nutrients, and biological compounds, but also the entry of drugs and the exit of waste products.” Medical Biochemistry, Mosby, 1999, pg 69 ISBN 0-7234-3012-8
Generally speaking, a fluid shift towards increased ICW suggests anabolic processes and improved nutrient status. Contrarily, a shift towards increased ECW suggests a decline in health status of the patient.
Consider this quote from the textbook Medical Biochemistry: (Mosby, 1999, pgs 267-268 ISBN 0-7234-3012-8) “Under physiologic conditions, the average concentration of all osmotically active substances in the ECF is 290 mmol/kg H2O, and this remains in equilibrium with the ICF. A change in the concentration of osmotically active substances in either of the water compartments creates a gradient of osmotic pressure and, consequently, movement of water between compartments.”
Causes of Fluid Shift: Electrolytes provide much of the osmotically active substances of both the ECF and the ICF. Sodium is the primary electrolyte of the ECF. Potassium is the primary electrolyte of the ICF. Magnesium is the key mineral responsible for triggering electrolyte pumping into and out of the cell. A deficiency in potassium or magnesium can cause a loss of ICW. An excess of sodium can cause an increase in ECW.
Toxins can increase the level of osmotically active substances and therefore cause an increase in the ECW. Patients with chronic heart failure and recent onset of peripheral edema had raised concentrations of endotoxin and plasma elevations of bacterial liopolysaccharides from the death of gram-negative bacteria. (Niebauer, J, Volk H-D, Kemp M, Dominguez M, et al. “Endotoxin and immune activation in chronic heart failure: a prospective cohort study.” Lancet. 1999; 353:1838-1842)
Ultimately the sodium potassium pump is fueled by ATP from the mitochondria. The DNA of Mitochondria is at least 10 times more susceptible to oxidative damage than the DNA within the nucleus of the cell. Mitochondrial inefficiency due to oxidative damage and / or nutrient insufficiency can be a cause of fluid shift. (Richter C, Park JW, Ames BN. Normal oxidative damage to mitochondrial and nuclear DNA is extensive. Proc Natl Acad Sci USA. 1988;85:6465-6467.)
Sodium balance is regulated via the action of the adrenal hormone aldosterone on the kidneys. Therefore, stress, by means of its impact on adrenal function, can influence fluid balance. Certainly kidney function can also influence fluid balance.
The integrity of the semi-permeable cell membrane is dependent upon the lipid content of the membrane. Low levels of the essential fatty acids, or high levels of artificial fats (trans fats) can have a negative impact on membrane integrity.
Inflammation due to trauma, toxicity or nutrient insufficiency can contribute to increases in extra-cellular fluid. Oxidant stress can damage cell membranes. High levels of glucose through the process of protein glycation can damage cell membrane proteins and impair the efficiency of active transport.
Disease processes associated with tissue catabolism can lead to a profound shift in body fluids. Cancer is an extreme example of a catabolic illness.
Allergy responses increase the overall body level of histamine and cause a shift of fluid from inside the cell to outside of the cell.
Phase angle: The phase angle is a value that is mathematically derived from the measured values of resistance and reactance. It is associated with cellular health and has been published as a leading indicator of prognosis of survival for patients with cancer, AIDS, and kidney disease. An increase in the phase angle is associated with improving health. Contrarily, a decline in phase angle is associated with failing health.
Impedance Index: The impedance index is also derived from the measured values of resistance and reactance. This number provides a general quantification of the health and vitality of the patient. The impedance index is the most sensitive indicator of changes in tissue health. Impedance index is directly proportional to tissue health.
Optimal Values: The determination of optimal values for any parameter is often a subject of great debate. The values that are presented here are the result of statistical analysis of several thousand patients by Dr. Robert Rakowski. The age of test subjects varied from 10 to 95 years old. The health status of patients varied from critically ill to elite professional athletes.
NOTE: Patients at all age groups have been found to meet and exceed the optimal values. These patients from all measurable parameters represented superior health and vitality. However, as was pointed out earlier, excellent BIA values cannot rule out the possibility of sudden death from a cardiovascular event and will not rule out the potential for malignancy.
Clinical Use of the BIA Data: The BIA provides a phenomenal cost-effective tool to monitor the effectiveness of Therapeutic Lifestyle Changes. In general, increases in phase angle, impedance index, and intracellular water are associated with improved health. Declines in body fat and extra-cellular water are also associated with improved health. Although rare, it is possible to have too little body fat. Females with low body fat may cease having menstrual cycles. Although it varies from patient to patient, females with body fat levels below 15% or total water values above 65% in the absence of edema are at risk for amenorrhea. Men with fat values below 10% or total body water above 70% may be sub-optimally lean.
The goal of this chapter is to provide basic information about the clinical use of Bio Impedance Analysis as a tool to assist in the monitoring of Therapeutic Lifestyle Changes. More information is available from the manufacturers of the BIA devices.
ST STEP 1: ANALYZE TOTAL BODY WATER VS. FAT FREE MASS: This marker refers to the hydration of the patient. Ø Higher is better. Ø Dehydration is < 69% TBW/FFM Ø If dehydrated begin Hydration Protocol Ø Retest in 24-48 Hours
STEP 2: ANALYZE PHASE ANGLE: This marker refers to the cellular health of the patient. Ø Higher is better. Declines with age Ø If below normal or person wants to increase use Phase Angle Protocol.
STEP 3: ANALYZE THE INTRA and EXTRA CELLULAR WATER: These two markers can determine if the patient has a toxicity issue: Ø 60+% ICW is optimal, declines with age. Ø To shift use Intracellular Water Protocol
STEP 4: ANALYZE FAT AND FAT-FREE MASS: These markers determine amount of metabolically active tissue in the body. Ø Optimal is age and sex dependent. Ø To alter refer to the Body Composition Protocol
STEP 5: ANALYZE EXTRA-CELLULAR MASS/BODY CELL MASS RATIO: This ratio will show improper weight loss (Sarcopenia) Ø Lower is better. Ø Upward shift shows improper weight loss. Ø Downward shift shows proper weight loss. Ø To alter refer to the Body Composition Protocol
STEP 6: ANALYZE THE BODY MASS INDEX: BMI This number relates to health and disease risk for the patient. Ø Lower is better Ø To alter refer to the Body Composition Protocol
STEP 7: ANALYZE THE BASAL METABOLIC RATE: BMR BMR is the calories burned at rest in 24 hours. Ø Increases as lean body mass increases Ø To increase see Body Composition Protocol |
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