Claims | Ability to diagnose disease from blood examined using dark field microscopy |
---|---|
Related scientific disciplines | Microscopy, dark field microscopy |
Year proposed | ca. 1925 |
Original proponents | Günther Enderlein |
Subsequent proponents | Robert O. Young |
Pseudoscientific concepts |
Live blood analysis (LBA), live cell analysis, Hemaview or nutritional blood analysis is the use of high-resolution dark field microscopy to observe live blood cells. Live blood analysis is promoted by some alternative medicine practitioners, who assert that it can diagnose a range of diseases. There is no scientific evidence that live blood analysis is reliable or effective, and it has been described as a fraudulent means of convincing patients that they are ill and should purchase dietary supplements.[1][2][3]
Looking At Live Blood Cells. I first came across Live Blood Cell Analysis about 5 years ago at a Naturopathic Convention in Las Vegas. A doctor there was demonstrating the procedure, so I had my blood analyzed. I was amazed by the simplicity of the process and what I could see directly. Blood gas analyzer. EPOC device is made to assist doctors during the medical consultations, in mobility or at the office. It allows to obtain blood gas, electrolytes and metabolites analyses results in 30 secondes after.
Live blood analysis is not accepted in laboratory practice and its validity as a laboratory test has not been established.[4] There is no scientific evidence for the validity of live blood analysis,[4] it has been described as a pseudoscientific, bogus and fraudulent medical test,[5][6] and its practice has been dismissed by the medical profession as quackery.[7] The field of live blood microscopy is unregulated, there is no training requirement for practitioners and no recognised qualification, no recognised medical validity to the results, and proponents have made false claims about both medical blood pathology testing and their own services, which some have refused to amend when instructed by the Advertising Standards Authority.[8]
It has its origins in the now-discarded theories of pleomorphism promoted by Günther Enderlein, notably in his 1925 book Bakterien-Cyklogenie.
In January 2014 prominent live blood proponent and teacher Robert O. Young was arrested and charged for practising medicine without a license,[9] and in March 2014 Errol Denton, a former student of his, a UK live blood practitioner, was convicted on nine counts in a rare prosecution under the Cancer Act 1939,[7] followed in May 2014 by another former student, Stephen Ferguson.
Overview[edit]
Proponents claim that live blood analysis provides information 'about the state of the immune system, possible vitamin deficiencies, amount of toxicity, pH and mineral imbalance, areas of concern and weaknesses, fungus and yeast.' Some even claim it can 'spot cancer and other degenerative immune system diseases up to two years before they would otherwise be detectable' or say they can diagnose 'lack of oxygen in the blood, low trace minerals, lack of exercise, too much alcohol or yeast, weak kidneys, bladder or spleen.'[1] Practitioners include alternative medicine providers such as nutritionists, herbologists, naturopaths, and chiropractors.[4]
Dark field microscopy is useful to enhance contrast in unstained samples, but live blood analysis is not proven to be useful for any of its claimed indications. Two journal articles published in the alternative medical literature found that darkfield microscopy seemed unable to detect cancer, and that live blood analysis lacked reliability, reproducibility, and sensitivity and specificity.[10][11]Edzard Ernst, professor of complementary medicine at the University of Exeter and University of Plymouth, notes: 'No credible scientific studies have demonstrated the reliability of LBA for detecting any of the above conditions.' Ernst describes live blood analysis as a 'fraudulent' means of convincing patients to buy dietary supplements.[1]Quackwatch has been critical of live blood analysis, noting dishonesty in the claims brought forward by its proponents.[12] The alternative medicine popularizer Andrew Weil dismissed live blood analysis as 'completely bogus', writing: 'Dark-field microscopy combined with live blood analysis may sound like cutting-edge science, but it's old-fashioned hokum. Don't buy into it.'[3]
Common diagnoses[edit]
There are several common diagnoses by the LBA practitioners that are actually based on observation of artifacts normally found in microscopy, and ignorance of basic biological science:[13][14]
- Acid in the blood: When the red blood cells stack on top of one another and appear like stacks of coins, it is called ‘rouleaux’ formation. By observation of the rouleaux, the LBA practitioners diagnose ‘acid in the blood’, while other practitioners suggest a weak pancreas. Rouleaux of red blood cells under the microscope is an artifact which occurs when the blood sample at the edge of the coverslip starts to dry out; where a large number of red blood cells clump together; or when the blood starts to clot when contacted with the glass. These artifacts are observed in only small, selected areas on the slide, while near the center of the slide the red blood cells are free floating. Blood acidosis is a severe illness and can not be diagnosed by observation of blood, nor treated by dietary supplements.[13][14]
- Uric acid crystals and/or cholesterol plaques: Microscopic splinters of glass are often present when the slide is not cleaned thoroughly. Observation of such shards is claimed by the LBA practitioners to be uric acid crystals or cholesterol plaques, and thus to be indicative of ‘acid imbalance, stress or poor lymphatic circulation’ among other vague ailments. Uric acid crystals and cholesterol plaques, if present, are not visible in the blood samples.[13][14]
- Parasites: Particles of dirt and debris, commonly found on glass slides not cleaned thoroughly, or slightly deformed red blood cells are mistaken to be parasites. Patients with parasites in the blood stream would be very sick and in need of immediate medical care, not by nutritional or herbal supplements or life style change as often recommended by LBA practitioners.[13][14]
- Bacteria and yeast: LBA practitioners observe small irregular shape on the red blood cell membrane, a common artifact, and claim it represents bacteria or yeasts budding off the edge of the cell membrane. This claim violates the basic principle of biology that each living organism is unique and can not be transformed from one into another. Presence of bacteria or yeasts in the blood indicates the patient is in danger of developing sepsis, a life-threatening condition.[13][14]
- Fermentations: Light spots on some red blood cells are identified by LBA practitioners as fermentations caused by high sugar content in the blood. Fermentation is a chemical reaction of breaking down sugar into alcohol and carbon dioxidecatalyzed by enzymes produced in yeast. The red blood cells are not yeasts and cannot ferment sugar.[13][14]
Regulatory issues[edit]
In 1996, the Pennsylvania Department of Laboratories informed three Pennsylvania chiropractors that Infinity2's 'Nutritional Blood Analysis' could not be used for diagnostic purposes unless they maintain a laboratory that has both state and federal certification for complex testing.[15]
In 2001, the Health and Human Services Office of the Inspector General issued a report on regulation of 'unestablished laboratory tests' that focused on live blood cell analysis and the difficulty of regulating unestablished tests and laboratories.[4]
In 2002, an Australian naturopath was convicted and fined for falsely claiming that he could diagnose illness using live blood analysis[16] after the death of a patient. He was acquitted of manslaughter. He subsequently changed his name and was later banned from practice for life.[17]
In 2005, the Rhode Island Department of Health ordered a chiropractor to stop performing live blood analysis. An attorney for the State Board of Examiners in Chiropractic Medicine described the test as 'useless' and a 'money-making scheme... The point of it all is apparently to sell nutritional supplements.' A state medical board official said that live blood analysis has no discernible value, and that the public 'should be very suspicious of any practitioner who offers this test.'[2]
In 2011, the UK General Medical Council suspended a doctor's licence to practise after he used live blood analysis to diagnose patients with Lyme disease. The doctor accepted he had been practising 'bad medicine'.[18]
In 2013, following several Advertising Standards Authority adjudications [19] against claims made by LBA practitioners, the Committee of Advertising Practice added new guidelines to their AdviceOnline database advising what LBA marketers may claim in their advertising material. These state that 'CAP is yet to see any evidence for the efficacy of this therapy which, without rigorous evidence to support it, should be advertised on an availability-only platform.' [20]
One of these practitioners, Errol Denton, who practised out of a serviced office in Harley Street, was prosecuted in December 2013 under the Cancer Act 1939, and chose to use a Freeman on the Land defence.[21] On March 20, 2014 he was convicted on nine counts under the Cancer Act 1939 and fined £9,000 plus around £10,000 in costs.[7][22] In April 2018, Denton was further convicted of two counts of 'engaging in unfair commercial practice' and one of 'selling food not of the quality demanded', for selling a bottle of colloidal silver drink to an undercover trading standards officer in February 2016, after examining a drop of her blood and from it claiming that she had dislocated her shoulder.[23][24] He was made the subject of a Criminal Behaviour Order, fined £2,250, and ordered pay £15,000 in costs.[25]
See also[edit]
References[edit]
- ^ abcErnst, Edzard (2005-07-12). 'Intrigued by the spectacular claims made for Live Blood Analysis? Don't be. It doesn't work'. The Guardian. Retrieved 2008-11-17.
- ^ abFreyer, Felice (2005-06-21). 'Chiropractor ordered to halt blood tests'. Providence Journal. Archived from the original on 2006-09-07. Retrieved 2008-11-17.
- ^ abWeil, Andrew (September 11, 2007). 'Ask Dr. Weil'. Arizona Daily Star. Retrieved November 9, 2009.
- ^ abcd'CLIA regulation of unestablished laboratory tests'(PDF). U.S. Department of Health and Human Services. July 2001. Retrieved January 26, 2009.
- ^Brigden ML (November 1995). 'Unproven (questionable) cancer therapies'. West. J. Med. 163 (5): 463–9. PMC1303171. PMID8533410.
- ^Morris A (March 2006). 'Complementary and alternative allergy tests'(PDF). Current Allergy and Clinical Immunology. 19 (1).
- ^ abcMendick, Robert (30 March 2014). 'Duped by the 'blood analyst' who says he can cure cancer'. Daily Telegraph.
- ^'Breast implant compensation, 'live' blood tests, and magic mirrors'. You and Yours. BBC Radio 4. March 15, 2012.
- ^Steve Fiorina. 'North County holistic care provider Robert Young pleads not guilty to multiple charges'. 10News. Retrieved 24 December 2015.
- ^El-Safadi S, Tinneberg HR, von Georgi R, Münstedt K, Brück F (June 2005). '[Does dark field microscopy according to Enderlein allow for cancer diagnosis? A prospective study]'. Forsch Komplementärmed Klass Naturheilkd (in German). 12 (3): 148–51. doi:10.1159/000085212. PMID15985779.
- ^Teut M, Lüdtke R, Warning A (2006). 'Reliability of Enderlein's darkfield analysis of live blood'. Altern Ther Health Med. 12 (4): 36–41. PMID16862741.
- ^Lowell, James (November 1986). 'Live Cell Analysis: High-Tech Hokum'. Quackwatch. Retrieved 2008-11-17.
- ^ abcdefPatterson, Thomas (2012). 'The Pseudoscience of Live Blood Cell Analysis'. Skeptical Inquirer. 36 (November/December): 43–45.
- ^ abcdefCrislip, Mark (13 February 2009). 'Live Blood Analysis: The Modern Auguries'. Science-Based Medicine. Retrieved 28 December 2012.
- ^Wlazelek, A. (1996-04-12). 'Chiropractors cease blood cell show and tell. State restricts the use of magnified images to sell vitamins, supplements'. The Morning Call. p. B6.
- ^'Former Lismore naturopath fined over newspaper ads'. Abc.net.au. 2002-05-24. Retrieved 2008-11-17.
- ^Court orders life ban on naturopath, Brisbane Times, April 4, 2008
- ^'MPTS Fitness to Practise Panel, 17th Oct - 2nd Nov 2011 & 6th - 8th Aug 2012'(PDF). Medical Practitioners Tribunal Service. Retrieved 3 June 2013.
- ^'ASA rulings on 'live blood''. Retrieved 7 July 2013.
- ^'Therapies: Live Blood Analysis'. 2013-07-03. Retrieved 7 July 2013.
- ^Harley Street practitioner claimed he could cure cancer and HIV with lifestyle changes and herbs, court hears, Daily Telegraph, Dec 11 2013
- ^Eastern Daily PressArchived 2014-03-21 at the Wayback Machine, 20 March 2014
- ^Herbert, Tom (3 April 2018). 'Homeopath who claimed he could cure cancer with food faces jail'. Metro. Retrieved 3 April 2018.
- ^'Blackfriars / T20160730'. causelist.org. Retrieved 3 April 2018.
- ^'ASA welcomes fine and Criminal Behaviour Order handed to Mr Errol Denton'. Advertising Standards Authority. Retrieved 20 April 2018.
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Live_blood_analysis&oldid=897037452'
(Redirected from Arterial blood gas)
Arterial-blood gas test | |
---|---|
Medical diagnostics | |
MeSH | D001784 |
MedlinePlus | 003855 |
LOINC | 24336-0 |
An arterial-blood gas (ABG) test measures the amounts of arterial gases, such as oxygen and carbon dioxide. An ABG test requires that a small volume of blood be drawn from the radial artery with a syringe and a thin needle,[1] but sometimes the femoral artery in the groin or another site is used. The blood can also be drawn from an arterial catheter.
An ABG test measures the blood gas tension values of the arterial partial pressure of oxygen, and the arterial partial pressure of carbon dioxide, and the blood's pH. In addition, the arterial oxygen saturation can be determined. Such information is vital when caring for patients with critical illnesses or respiratory disease. Therefore, the ABG test is one of the most common tests performed on patients in intensive-care units. In other levels of care, pulse oximetry plus transcutaneous carbon-dioxide measurement is a less invasive, alternative method of obtaining similar information.
An ABG test can also measure the level of bicarbonate in the blood. Many blood-gas analyzers will also report concentrations of lactate, hemoglobin, several electrolytes, oxyhemoglobin, carboxyhemoglobin, and methemoglobin. ABG testing is mainly used in pulmonology and critical-care medicine to determine gas exchange across the alveolar-capillary membrane. ABG testing also has a variety of applications in other areas of medicine. Combinations of disorders can be complex and difficult to interpret, so calculators,[2]nomograms, and rules of thumb[3] are commonly used.
ABG samples originally were sent from the clinic to the medical laboratory for analysis. Newer equipment lets the analysis be done also as point-of-care testing, depending on the equipment available in each clinic.
- 1Sampling and analysis
- 2Parameters and reference ranges
Sampling and analysis[edit]
Bench top analyzer ABL800 FLEX - Radiometer Medical
Modern, blood gas analyzer. This device is capable of reporting pH, pCO2, pO2, SatO2, Na+, K+, Cl−, Ca2+, Hemoglobin (total and derivatives: O2Hb, MetHb, COHb, HHb, CNHb, SHb ), Hematocrit, Total bilirubin, Glucose, Lactate and Urea. (Cobas b 221 - Roche Diagnostics).
Arterial blood for blood-gas analysis is usually drawn by a respiratory therapist and sometimes a phlebotomist, a nurse, a paramedic or a doctor.[4] Blood is most commonly drawn from the radial artery because it is easily accessible, can be compressed to control bleeding, and has less risk for vascular occlusion. The selection of which radial artery to draw from is based on the outcome of an Allen's test. The brachial artery (or less often, the femoral artery) is also used, especially during emergency situations or with children. Blood can also be taken from an arterial catheter already placed in one of these arteries.
There are plastic and glass syringes used for blood gas samples. Most syringes come pre-packaged and contain a small amount of heparin, to prevent coagulation. Other syringes may need to be heparinised, by drawing up a small amount of liquid heparin and squirting it out again to remove air bubbles. Once the sample is obtained, care is taken to eliminate visible gas bubbles, as these bubbles can dissolve into the sample and cause inaccurate results. The sealed syringe is taken to a blood gas analyzer.[5] If a plastic blood gas syringe is used, the sample should be transported and kept at room temperature and analyzed within 30 min. If prolonged time delays are expected (i.e., greater than 30 min) prior to analysis, the sample should be drawn in a glass syringe and immediately placed on ice.[6] Standard blood tests can also be performed on arterial blood, such as measuring glucose, lactate, hemoglobins, dys-haemoglobins, bilirubin and electrolytes.
Derived parameters include bicarbonate concentration, SaO2, and base excess. Bicarbonate concentration is calculated from the measured pH and PCO2 using the Henderson-Hasselbalch equation. SaO2 is derived from the measured PO2 and calculated based on the assumption that all measured hemoglobin is normal (oxy- or deoxy-) hemoglobin.[7]
Calculations[edit]
Detail of measurement chamber of a modern blood gas analyzer showing the measurement electrodes. (Cobas b 121 - Roche Diagnostics)
The machine used for analysis aspirates this blood from the syringe and measures the pH and the partial pressures of oxygen and carbon dioxide. The bicarbonate concentration is also calculated. These results are usually available for interpretation within five minutes.
Two methods have been used in medicine in the management of blood gases of patients in hypothermia: pH-stat method and alpha-stat method. Recent studies suggest that the α-stat method is superior.
- pH-stat: The pH and other ABG results are measured at the patient's actual temperature. The goal is to maintain a pH of 7.40 and the arterial carbon dioxide tension (paCO2) at 5.3 kPa (40 mmHg) at the actual patient temperature. It is necessary to add CO2 to the oxygenator to accomplish this goal.
- α-stat (alpha-stat): The pH and other ABG results are measured at 37 °C, despite the patient's actual temperature. The goal is to maintain the arterial carbon dioxide tension at 5.3 kPa (40mmHg) and the pH at 7.40 when measured at +37 °C.
Both the pH-stat and alpha-stat strategies have theoretical disadvantages. α-stat method is the method of choice for optimal myocardial function. The pH-stat method may result in loss of autoregulation in the brain (coupling of the cerebral blood flow with the metabolic rate in the brain). By increasing the cerebral blood flow beyond the metabolic requirements, the pH-stat method may lead to cerebral microembolisation and intracranial hypertension.[7]
Guidelines[edit]
- A 1 mmHg change in PaCO2 above or below 40 mmHg results in 0.008 unit change in pH in the opposite direction.[8]
- The PaCO2 will decrease by about 1 mmHg for every 1 mEq/L reduction in [HCO−
3] below 24 mEq/L - A change in [HCO−
3] of 10 mEq/L will result in a change in pH of approximately 0.15 pH units in the same direction. - Assess relation of pCO2 with pH: If pCO2 & pH are moving in opposite directions i.e., pCO2 ↑ when pH is <7.4 or pCO2 ↓ when pH > 7.4, it is a primary respiratory disorder. If pCO2 & pH are moving in same direction i.e., pCO2 ↑when pH is >7.4 or pCO2 ↓ when pH < 7.4, it is a primary metabolic disorder.[9]
Parameters and reference ranges[edit]
These are typical reference ranges, although various analysers and laboratories may employ different ranges.
Analyte | Range | Interpretation |
---|---|---|
pH | 7.34–7.44[10] | The pH or H+ indicates if a person is acidemic (pH < 7.35; H+ >45) or alkalemic (pH > 7.45; H+ < 35). |
H+ | 35–45 nmol/L (nM) | |
Arterial oxygen partial pressure (PaO2) | 10–13 kPa 75–100 mmHg[10] | A low PaO2 indicates that the person is not oxygenating properly, and is hypoxemic. (Note that a low PaO2 is not required for the person to have hypoxia.)[why?] At a PaO2 of less than 60 mm Hg, supplemental oxygen should be administered. |
Arterial carbon dioxide partial pressure (PaCO2) | 4.7–6.0 kPa 35–45 mmHg[10] | The carbon dioxide partial pressure (PaCO2) is an indicator of CO2 production and elimination: for a constant metabolic rate, the PaCO2 is determined entirely by its elimination through ventilation.[11] A high PaCO2 (respiratory acidosis, alternatively hypercapnia) indicates underventilation (or, more rarely, a hypermetabolic disorder), a low PaCO2 (respiratory alkalosis, alternatively hypocapnia) hyper- or overventilation. |
HCO3– | 22–26 mEq/L | The HCO3– ion indicates whether a metabolic problem is present (such as ketoacidosis). A low HCO3– indicates metabolic acidosis, a high HCO3– indicates metabolic alkalosis. As this value when given with blood gas results is often calculated by the analyzer, correlation should be checked with total CO2 levels as directly measured (see below). |
SBCe | 21 to 27 mmol/L | the bicarbonate concentration in the blood at a CO2 of 5.33 kPa, full oxygen saturation and 37 Celsius.[12] |
Base excess | −2 to +2 mmol/L | The base excess is used for the assessment of the metabolic component of acid-base disorders, and indicates whether the person has metabolic acidosis or metabolic alkalosis. Contrasted with the bicarbonate levels, the base excess is a calculated value intended to completely isolate the non-respiratory portion of the pH change.[13] There are two calculations for base excess (extra cellular fluid - BE(ecf); blood - BE(b)). The calculation used for the BE(ecf) = cHCO3– − 24.8 + 16.2 × (pH − 7.4). The calculation used for BE(b) = (1 − 0.014 × hgb) × (cHCO3– − 24.8 + (1.43 × hgb + 7.7) × (pH − 7.4). |
total CO2 (tCO2 (P)c) | 23–30 mmol/L[14] 100–132 mg/dL[15] | This is the total amount of CO2, and is the sum of HCO3– and PCO2 by the formula: tCO2 = [HCO3–] + α×PCO2, where α=0.226 mM/kPa, HCO3– is expressed in millimolar concentration (mM) (mmol/L) and PCO2 is expressed in kPa |
O2 Content (CaO2, CvO2, CcO2) | vol% (mL O2/dL blood) | This is the sum of oxygen dissolved in plasma and chemically bound to hemoglobin as determined by the calculation: CaO2 = (PaO2 × 0.003) + (SaO2 × 1.34 × Hgb) where hemoglobin concentration is expressed in g/dL.[16] |
Contamination of the sample with room air will result in abnormally low carbon dioxide and possibly elevated oxygen levels, and a concurrent elevation in pH. Delaying analysis (without chilling the sample) may result in inaccurately low oxygen and high carbon dioxide levels as a result of ongoing cellular respiration.
pH[edit]
BMP/ELECTROLYTES: | |||
Na+ = 140 | Cl− = 100 | BUN = 20 | / |
Glu = 150 | |||
K+ = 4 | CO2 = 22 | PCr = 1.0 | |
ARTERIAL BLOOD GAS: | |||
HCO3− = 24 | paCO2 = 40 | paO2 = 95 | pH = 7.40 |
ALVEOLAR GAS: | |||
pACO2 = 36 | pAO2 = 105 | A-a g = 10 | |
OTHER: | |||
Ca = 9.5 | Mg2+ = 2.0 | PO4 = 1 | |
CK = 55 | BE = −0.36 | AG = 16 | |
SERUM OSMOLARITY/RENAL: | |||
PMO = 300 | PCO = 295 | POG = 5 | BUN:Cr = 20 |
URINALYSIS: | |||
UNa+ = 80 | UCl− = 100 | UAG = 5 | FENa = 0.95 |
UK+ = 25 | USG = 1.01 | UCr = 60 | UO = 800 |
PROTEIN/GI/LIVER FUNCTION TESTS: | |||
LDH = 100 | TP = 7.6 | AST = 25 | TBIL = 0.7 |
ALP = 71 | Alb = 4.0 | ALT = 40 | BC = 0.5 |
AST/ALT = 0.6 | BU = 0.2 | ||
AF alb = 3.0 | SAAG = 1.0 | SOG = 60 | |
CSF: | |||
CSF alb = 30 | CSF glu = 60 | CSF/S alb = 7.5 | CSF/S glu = 0.4 |
The normal range for pH is 7.35–7.45. As the pH decreases (< 7.35), it implies acidosis, while if the pH increases (> 7.45) it implies alkalosis. In the context of arterial blood gases, the most common occurrence will be that of respiratory acidosis. Carbon dioxide is dissolved in the blood as carbonic acid, a weak acid; however, in large concentrations, it can affect the pH drastically. Whenever there is poor pulmonary ventilation, the carbon dioxide levels in the blood are expected to rise. This leads to a rise of carbonic acid, leading to a decrease in pH. The first buffer of pH will be the plasma proteins, since these can accept some H+ ions to try to maintain acid-base homeostasis. As carbon dioxide concentrations continue to increase (PaCO2 > 45 mmHg), a condition known as respiratory acidosis occurs. The body tries to maintain homeostasis by increasing the respiratory rate, a condition known as tachypnea. This allows much more carbon dioxide to escape the body through the lungs, thus increasing the pH by having less carbonic acid. If a person is in a critical setting and intubated, one must increase the number of breaths mechanically.
Respiratory alkalosis (Pa CO2 < 35 mmHg) occurs when there is too little carbon dioxide in the blood. This may be due to hyperventilation or else excessive breaths given via a mechanical ventilator in a critical care setting. The action to be taken is to calm the person and try to reduce the number of breaths being taken to normalize the pH. The respiratory pathway tries to compensate for the change in pH in a matter of 2–4 hours. If this is not enough, the metabolic pathway takes place.
Under normal conditions, the Henderson–Hasselbalch equation will give the blood pH
where:
- 6.1 is the acid dissociation constant (pKa) of carbonic acid (H
2CO
3) at normal body temperature - HCO3– is the concentration of bicarbonate in the blood in mEq/L
- PaCO2 is the partial pressure of carbon dioxide in the arterial blood in torr
The kidney and the liver are two main organs responsible for the metabolic homeostasis of pH. Bicarbonate is a base that helps to accept excess hydrogen ions whenever there is acidaemia. However, this mechanism is slower than the respiratory pathway and may take from a few hours to 3 days to take effect. In acidaemia, the bicarbonate levels rise, so that they can neutralize the excess acid, while the contrary happens when there is alkalaemia. Thus when an arterial blood gas test reveals, for example, an elevated bicarbonate, the problem has been present for a couple of days, and metabolic compensation took place over a blood acedemia problem.
In general, it is much easier to correct acute pH derangement by adjusting respiration. Metabolic compensations take place at a much later stage. However, in a critical setting, a person with a normal pH, a high CO2, and a high bicarbonate means that, although there is a high carbon dioxide level, there is metabolic compensation. As a result, one must be careful as to not artificially adjust breaths to lower the carbon dioxide. In such case, lowering the carbon dioxide abruptly means that the bicarbonate will be in excess and will cause a metabolic alkalosis. In such a case, carbon dioxide levels should be slowly diminished.
See also[edit]
References[edit]
- ^Dr Colin Tidy (26 Jan 2015). 'Arterial Blood Gases - Indications and Interpretation'. Patient. Reviewed by Dr Adrian Bonsall. Retrieved 2017-01-02.
- ^Baillie K. 'Arterial Blood Gas Interpreter'. prognosis.org. Retrieved 2007-07-05. - Online arterial blood gas analysis
- ^Baillie, JK (2008). 'Simple, easily memorised 'rules of thumb' for the rapid assessment of physiological compensation for acid-base disorders'. Thorax. 63 (3): 289–90. doi:10.1136/thx.2007.091223. PMID18308967.
- ^Aaron SD, Vandemheen KL, Naftel SA, Lewis MJ, Rodger MA (2003). 'Topical tetracaine prior to arterial puncture: a randomized, placebo-controlled, clinical trial'. Respir. Med. 97 (11): 1195–1199. doi:10.1016/S0954-6111(03)00226-9. PMID14635973.
- ^Horn, Klaus; Gruber, Rudolf; Ugele, Bernhard; Küster, Helmut; Rolinski, Boris (1 October 2001). 'Total Bilirubin Measurement by Photometry on a Blood Gas Analyzer: Potential for Use in Neonatal Testing at the Point of Care,'. Clinical Chemistry. pp. 1845–1847.
- ^Procedures for the Collection of Arterial Blood Specimens; Approved Standard—Fourth Edition (Procedures for the Collection of Arterial Blood Specimens; Approved Standard—Fourth Edition ). Clinical and Laboratory Standards Institute. 2004. ISBN978-1-56238-545-3.
- ^ abKofstad J (1996). 'Blood Gases and Hypothermia: Some Theoretical and Practical Considerations'. Scand J Clin Lab Invest. (Suppl). 224: 21–26. PMID8865418.
- ^Stoelting: Basics of Anesthesia, 5th ed. p 321.
- ^'Arterial Blood Gas (ABG) In 4 Steps'. www.edulanche.com/. EduLanche. Retrieved 2016-05-13.
- ^ abcNormal Reference Range Table from The University of Texas Southwestern Medical Center at Dallas. Used in Interactive Case Study Companion to Pathologic basis of disease.
- ^Baillie K, Simpson A. 'Altitude oxygen calculator'. Apex (Altitude Physiology Expeditions). Retrieved 2006-08-10. - Online interactive oxygen delivery calculator
- ^Acid Base Balance (page 3)
- ^RCPA Manual: Base Excess (arterial blood)
- ^'ABG (Arterial Blood Gas)'. Brookside Associates. Retrieved 2017-01-02.
- ^Derived from molar values using molar mass of 44.010 g/mol
- ^Hemoglobin and Oxygen Transport. Charles L. Webber, Jr., Ph.D.
External links[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Arterial_blood_gas_test&oldid=899059555'