>80%), suggesting that the VBG is extremely close to the ABG. Preference cookies are used to store user preferences to provide content that is customized and convenient for the users, like the language of the website or the location of the visitor. Example: Are my colleagues (other specialists) going to accept a venousRead more . official website and that any information you provide is encrypted HCO3 calculation is also provided (some blood gaz machines do not provide this result). J Formos Med Assoc. This again emphasizes that small differences in ABG values aren't clinically relevant. As measured on mixed venous gas from PA catheter. Bethesda, MD 20894, Web Policies What are the disadvantages of giving bicarbonate in the setting of acute metabolic acidosis? ABG/VBG isn't needed to evaluate metabolic pH disorders Complete analysis of pH status requires blood gas analysis, but all you need to determine the metabolic pH disorders is an electrolyte panel. PaCO2 35 - 45 mmHg. This data doesnt investigate the femoral or SVC sites. font: 14px Helvetica, Arial, sans-serif; The carbonic acid from step b disassociates into a bicarbonate ion and a hydrogen ion H2CO3 HCO3- + H+. An ABG has a number of uses, the VBG can be substituted for some of these uses but not for others. The normal AG depends on serum albumin. On the contrary, if the kidneys deteriorate in their function, we name the acidosis/alkalosis metabolic. Evaluate for physiologic compensation for the acid-base disorder. Conversion of VBG values into ABG values using the simplified saturation model with coefficients derived above. Learn how your comment data is processed. I also have a blog to share what I have leaned and seen. A doctor begins by taking a blood sample from an artery, most commonly the radial artery, or sometimes the femoral and brachial arteries. If you'd like to estimate arterial blood pH and learn more about it, use our arterial blood pH calculator. Physiological Approach to Assessment of AcidBase Disturbances. You may also be interested in our guide to performing an ABG, ABG quiz or our collection of ABG interpretation flashcards. Dr. No's data was the most precise (possibly because it required specific time intervals between ABG and VBG samples). West J Med 1991;155:146-151. Anaesthesia. margin-right: 10px; His one great achievement is being the father of three amazing children. The expected "normal" range for AG can be calculated by 2.5 x albumin (g/dl) +/- 2. Epub 2018 Sep 8. Hemoglobin. Careers. Venous blood gas. Changes in blood gas values over time (may fluctuate rapidly). In addition, we derived an adjustment formula for ABG conversion from central VBG: (1) arterial pH = venous pH + 0.05 units and (2) arterial Pco2 = venous Pco2 - 5 mm Hg. These cookies do not store any personal information. Iatrogenic hypoventilation (insufficient respiratory rate or tidal volumes on mechanical ventilation). However, it must be noted that clinically stable patients have random fluctuations in pH and pCO2 with a standard deviations of 0.015-0.02 and 1.5-3 mm, respectively (4). SID means Strong Ion Difference (SIDa and SIDe for SID apparent or effective). 2014;19(2):168, Kelly AM, Klim S, Rees SE. This is intriguing, and could have great utility at the bedside. Before There are significant differences between specialties with regards to the opinion towards using VBG data. %. Your model is interesting and logical. Comparison and agreement between venous and arterial gas analysis in cardiopulmonary patients in Kashmir valley of the Indian subcontinent. It is used to help us to recognize when a patient's body is extracting more oxygen than normally. This site represents our opinions only. Years passed. The reason respiratory disorders have acute/chronic phases is that it takes the kidneys several days to fully compensate. Emergency physicians seem to best understand the utility of VBGs (because they are constantly dealing with sick, undifferentiated patients who mostly don't have arterial catheters). 44 episodes of DKA were identified after acidosis was established by an arterial pH less than 7.35. We concluded that central VBG parameters of pH and Pco2 are potentially good surrogates for determining arterial pH and Pco2 in a stable patient without severe acid-base disturbances. The saturation model and the simplified saturation model had the same performance in converting from VBG into ABG values. To calculate the PaO 2 /FiO 2 ratio, the PaO 2 is measured in mmHg and the FiO 2 is expressed as a decimal between 0.21 and 1. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. #mc-embedded-subscribe-form .mc_fieldset { How to convert venous blood gas values to arterial values Arterial blood gas is the gold standard for blood gas and acid-based testing in critical care. Subsequent to failed publication attempts as described above, I requested data from investigators who had more recently published papers. You need initial traffic only. This site uses Akismet to reduce spam. Osmolal gap = measured serum osmolality calculated serum osmolality. How to get massive traffic? Unless Ive been doing it wrong all these years. When blood travels through your lungs, oxygen enters the bloodstream, while carbon dioxide exits the bloodstream and enters the lungs. The concentration of a solute gas in a solution is directly proportional to the partial pressure of that gas above the solution" according to Henry's Law (k = P/C, therefore C = P/k). Least precise: expected pCO2 = last two digits of pH (e.g. The normal values should be between 8 and 16 mEq/L. The simplified saturation model provided the best prediction of ABG values. In studies of hemodynamically stable patients, the mean difference between arterial and central venous pH and Pco2 was 0.03 units and 4-6.5 mm Hg, respectively. 2001, 2023 The Regents of the University of California, VBG can provide reliable estimation for pH (0.02-0.04. However, the necessary sample of arterial blood can be difficult to obtain due to diminished pulses or patient movement. Here are other differences. This can be done with the use of a third assumption. It describes the pH as a measure of acidity in biological and chemical systems. Serum CK if there is suspicion for massive rhabdomyolysis. If the pCO2 is too high, as reflected in the second image, then it cannot calculate the bicarb and you're left with a blank value. BMI calculator compares your weight with your height and gives you an estimation of how healthy your weight is. PMID, McCanny P, Bennett K, Staunton P, McMahon G. Venous vs arterial blood gases in the assessment of patients presenting with an exacerbation of chronic obstructive pulmonary disease. PMID. Conversion of VBG values into ABG values using a method published by. The above data pertains to VBGs drawn from the arm. pH < 7.35 acidemia pH > 7.45 alkalemia This is usually the primary disorder Then, Dr. Hasselbalch re-expressed that formula in a more complicated manner to study acid-base disorders, which resulted in the HendersonHasselbalch equation. What can you calculate using venous blood gas levels? Due to thicker, muscular and innervated walls, arteries are also more painful to puncture than veins. Based on this data, I developed formulae for conversion of VBG values into ABG values. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Central venous blood gas (VBG) is a potentially more accessible alternative to ABG sampling. More on the use of ABG values in clinical decision-making in upcoming posts. Accessibility Bloom BM, Grundlingh J, Bestwick JP, Harris T. Eur J Emerg Med. Is this applicable to VBGs from all locations? And you can look our website about free proxy. This is done as an alternative method to arterial blood gas (ABG) test when the individual has diminished pulses due to poor peripheral blood circulation or low blood pressure. The equation demonstrates an equilibrium, between carbon dioxide, and hydrogen ions + bicarbonate. CNS: anxiety, pain, primary CNS disorders, Cheyne-Stokes respirations. Tissues in the hand extract oxygen and generate carbon dioxide (in a ratio equal to the respiratory quotient). The aim of this study was to test the reliability of aVBG compared to ABG in an emergency department (ED) setting. Respirology. Data from two patients in two different studies were censored (in one case because pCO2 was immeasurably high, and in another case because the venous oxygen saturation was >25% higher than the arterial oxygen saturation). Doi :10.1056/NEJMra1003327. Copyright 2013-2023 Oxford Medical Education Ltd. Myasthenia Gravis (MG) Neurological Examination, Questions about DVT (Deep Vein Thrombosis), Endotracheal tube (ETT) insertion (intubation), Supraglottic airway (e.g. O 5-oxoproline (from chronic acetaminophen use, often in those with malnutrition), D D-lactic acid (from short-gut syndrome), K Ketones* (from diabetes, alcohol, or starvation). . Agreement between central venous and arterial blood gas measurements in the intensive care unit. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. He presents with an acute viral chest infection and is admitted for Vapotherm / Optiflow support His ABG in air shows:- pH 7.33 pCO 2 This improved accuracy substantially, compared to assuming that ABG values are roughly equal to VBG values: These equations aren't currently ready for clinical use (they require further validation). Minimize the duration oftourniquet application (e.g., if the patient has a venous catheter that allows blood to be withdrawn, slowly pull blood off the venous catheter. Alternate approach to answer this question: correcting the bicarb. Read on to find out how to calculate this metric and what normal BMI ranges are. The calculation used to generate s O 2 from p O 2 (a) is based on the relationship between the two described by the oxygen dissociation curve. For example, one of the classic errors in ABG interpretation is over-interpreting random variation in sequential ABG measurements. The pO 2 on a VBG bears no relationship to the paO2. Peripheral venous and arterial blood gas analysis in adults: are they comparable? He coordinates the Alfred ICUs education and simulation programmes and runs the units educationwebsite,INTENSIVE. This acid base calculator estimates both the anion gap and provides you with an arterial blood gas interpretation. The standard value of AG is between 8 - 16 mEq/L. Basic metabolic panel. (arm, leg, femoral vein, SVC). border: none; beats/min. OR if urine sodium <20 mEq/L (insufficient Na+ delivery to the distal tubule does not allow for H+ exchange required for urinary acidification). The PaO 2 /FiO 2 ratio is a valuable clinical . FOIA When you're done listening to the podcast. The relationship between pH and CO2 is complex, based partially on the Henderson-Hasselbach equation. The total, expected, BE is then the sum of the individual calculated BE effects. Urinary tract diversions (uretosigmoidostomy or fistula, ileal conduit). Date: 08/27/03 Expected Values Reportable Reference Test/Abbreviation Units* Range Range (arterial) (venous) Partial Pressure Carbon Dioxide/PCO2 mmHg 5 - 130 35 - 453 41 - 51 kPa 0.67 - 17.33 4.67 - 6.00 5.47 - 6.80 Kraut JA, Nagami GT. Venous to arterial conversion (v-TAC), a mathematical method, has been developed recently to convert peripheral venous blood gas (VBG) values to arterialized VBG (aVBG) values. Reducing pain by using venous blood gas instead of arterial blood gas (VEINART): a multicentre randomised controlled trial. Simple formulae utilizing venous oxygen saturation may improve our ability to predict ABG values based on VBG values. In addition, we derived an adjustment formula for ABG conversion from central VBG: (1) arterial pH = venous pH + 0.05 units and (2) arterial Pco2 = venous Pco2 - 5 mm Hg. shock state, poor pick up), painful (should be performed with local anaesthetic in conscious patients), venous sampling may better represent the tissue milieu, 100% sensitive in detecting arterial hypercarbia in COPD exacerbation using cutoff of PaCO2 45 mmHg and laboratory based testing (McCanny et al, 2012), i.e. One is interested in the bicarbonate value because it is the most important extracellular fluid buffer, accounting for 75% of total buffering in metabolic acid-base disturbances (the rest being performed by blood proteins, such as haemoglobin). Normal gap = 0-6 (can be ~10 in ICU given other unknown osmoles). National Library of Medicine Overall I continue to believe that VBG values are usually fine for clinical decision making. Taking a blood sample from an artery using a needle may cause a few minutes of discomfort. A mixed acid-based disorder consists of any combination of at least two disorders: two metabolic disturbances OR one respiratory and one metabolic. Chris is an Intensivist and ECMO specialist at theAlfred ICU in Melbourne. Byrne AL, Bennett M, Chatterji R, Symons R, Pace NL, Thomas PS. Your body normally tightly regulates the amount of oxygen and carbon dioxide in your . We commonly calculate it without the potassium value, i.e., just with the sodium, chloride, and bicarbonate value. An arterial blood gas (ABG) is the traditional method of estimating the systemic carbon dioxide tension and pH, usually for the purpose of assessing ventilation and/or acid-base status. Arterial Blood Gas (ABG) Analyzer - MDCalc Arterial Blood Gas (ABG) Analyzer Interprets ABG. Check what you could have accomplished if you get out of your social media bubble. MDCalc loves calculator creators - researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. With the use of VBGs gaining gradual acceptance, it is natural that more attention will turn to the topic of mathematical arterialization. VBG compared to ABG pH .03 lower. Urine toxicology screen, serum salicylate levels, ethanol levels and possibly acetaminophen levels (if history/concern for ingestion). Acid-base homeostasis is a highly complex process in the body. Respiratory compensation of metabolic pH disorders is nearly immediate. All you need is the results of the patient's blood sample. Therefore, if the lungs stop working, one should present with metabolic compensation. Heart Lung. Base excess is not profoundly changing in capillaries (no strong acids are produced such as lactic acid). - Step 1 : enter the required values, obtained from blood gaz machine and lab results. large volume resuscitation with normal saline), plasma exchange. Measures the levels of oxygen and carbon dioxide in venous blood. The authors declare no conflicts of interest. Actual bicarbonate is the concentration of hydrogen carbonate in the plasma. Peripheral venous and arterial blood gas analysis in adults: are they comparable? Here they are and their normal numeric values (commit them to memory): pH: 7.35-7.45 CO2: 35-45 (CO2 lab value ALWAYS indicates a RESPIRATORY issue) The 5mmol/L correction accounts for the normal range of bicarbonate. #mergeRow-gdpr { No major flaws were found in the analysis, but it was deemed to beirrelevant (one reviewer wrote This meta-analysis describes well a way to calculate ABG from VBG. This does assume that there is a roughly stable magnitude of error across different clinical situations. I reached out to some additional investigators who had recently published data, and obtained one fresh dataset. If the pt is intubated, the oxygen may be high and make one mistake venous blood for arterial blood unless one also gets an abg for comparison 2.how much can you infer from a low oxygen on a vbg? Interestingly, the Reference Manual for the local ABG analyser lists a large number of molecules which can potentialy cause interference with lactate measurement- notably ascorbic acid, bilirubin, citrate, EDTA, ethanol, heparin, glucose, paracetamol, salicylate and urea. Arterial blood gas (ABG) analysis is an essential tool in the clinical assessment of acutely ill patients. Part compensation occurs when the PCO2 and HCO3 . Usually the sample is taken from an artery in the wrist (radial artery). Likewise, a very early ingestion may present with elevated osmolal gap but normal anion gap. sample processing, random variation in blood gas values over time, etc.). and transmitted securely. For medical use, it calculates the pH of the blood by inserting the HCO (in mEq/L or mmol/L) and PaCO (in mmHg or torr) values in the following formula: pH = 6.1 + log10[HCO / (0.0308 PaCO)], Wondering how many helium balloons it would take to lift you up in the air? Zeserson 2016). If the VBG oxygen saturation is low, the following techniques might be used to obtain a VBG with a higher oxygen saturation: This analysis has numerous limitations, most notably some of the most precise data has been redacted. May I recommend you to have a look at the v-TAC software by OBI Medical (www.obimedical.com) to convert VBG values to arterial values. There are several methods for estimating pCO2 compensation: Expected pCO2 = [(1.5 x serum HCO3) + 8] 2. After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australias Northern Territory, Perth and Melbourne. the studies we looked at show good correlation with pH and pCO2. The difference between ABG and VBG values depends on the amount of cellular respiration that occurs in the tissues in between. A more detailed information might be implemented in the future version of the software. Necessary cookies are absolutely essential for the website to function properly. It's time for us to explain how we can use this acid-base calculator in practice. It means that the patient's anion gap equals 8 mEq/L, which is within the normal range. SIG is the Strong Ion Gap. Clipboard, Search History, and several other advanced features are temporarily unavailable. If osmolal gap > 10, consider ingestion of toxic alcohol, but note that osmolal gap is NOT very sensitive. If concerned for an ingestion, calculate the. I have not seen this info but it seems like it would be available in other studies comparing vbgs and abgs unless they didnt record the oxygen levels 1a. official version of the modified score here. BE is the Base excess (SBE for Standar Base Excess). New England Journal of Medicine. Anion gap, AG, equals the difference between most prevalent cation, sodium, Na+, and the sum of most common anions (chloride Cl- and bicarbonate HCO3-). The aim of this study was to test the reliability of aVBG compared to ABG in an emergency department (ED) setting. SIG is the Strong Ion Gap. PMID, Middleton P, Kelly AM, Brown J, Robertson M. Agreement between arterial and central venous values for pH, bicarbonate, base excess, and lactate. the clinical value of VBG (venous blood gas) is discussed in this video, when can it be used as an alternative to ABG (arterial blood gas), how to interpret . We try our best to make our Omni Calculators as precise and reliable as possible. It has weighed on me that I failed to publish these results, which I continue to believe are valid and potentially useful. Yet, even a slight decrease in their function can lead to significant illness, such as acidosis or alkalosis. This is amazing to me! time interval between VBG and ABG, processing of ABG and VBG specimens, etc.). The process of blood gas and pH measurement involves preheating the arterial blood sample to normal body temperature (37 C) prior to measurement of pH, partial pressure of oxygen (pO 2) and partial pressure of carbon dioxide (pCO 2).This ensures that results reflect in vivo temperature condition. To be used for the evaluation of the respiratory component of an acidosis / alkalosis. One can consider temporary NaHCO3 administration in the setting of severe metabolic acidosis (pH < 7.1) or to facilitate permissive hypercarbia. The calculator also determines whether the state is compensated or uncompensated. Of these, three studies involving 314 patients were analyzed. Determining the PaO 2 /FiO 2 requires arterial blood gas (ABG) analysis. These are real scientific discoveries about the nature of the human body, which can be invaluable to physicians taking care of patients. As an example, if a patient has a PaO 2 of 100 mmHg while receiving 80 percent oxygen, then the PaO 2 /FiO 2 ratio is 125 mmHg (ie, 100 mmHg/0.8). These datasets support the existence of a universal and linear relationship (the red lines in each set of figuresbelow have matching slopes): That looks nice, but we need to be a bit more precise. Unauthorized use of these marks is strictly prohibited. Imagine blood flowing from the radial artery to a vein in the hand. Privacy Policy. See. Thus, the change in pH may be approximated as proportional to the change in carbon dioxide: This creates the saturation model, which may be summarized as follows (where k1 and k2 are empirically derived constants): This provides a way to estimate ABG values based on a combination of VBG values plus simultaneous pulse oximetry. May I try to summarize this article and post my study note no my blog (In Chinese)? Normal Arterial Blood Gas Values pH : 7.36-7.44 PaCO2 : 36-44 mm Hg HCO3 : 22-26 mEq/L Legal Notices and Disclaimer All Information contained in and produced by the Pediatric Oncall system is provided for educational purposes only. 2011 Jan;6(1):33-7. This data suggests that a simplified saturation model may predict ABG values with a precision that could be adequate for clinical use. Haber RJ. There are 2 kinds of blood gas tests: one is done using blood from an artery (ABG) and one is done using blood from a vein (VBG). Calcs that help predict probability of a disease, Subcategory of 'Diagnosis' designed to be very sensitive, Disease is diagnosed: prognosticate to guide treatment. Administration of chloride (e.g. Albumin. Note that these may vary slightly between analysers. Proceed to step 2b. ABG: VBG: Arterial blood gas. The venous blood gas calculator estimates the venous blood pH using bicarbonate (HCO) values and arterial carbon dioxide partial pressure (PaCO) in the patient's blood. However, it's probably better than the most common method used in the literature, which is to relate arterial and venous parameters to each other directly using linear regression equations (where c1-c4 are constants): Sixteen studies were identified from the literature search as relevant for consideration. If we calculate the constants involved in these equations from different datasets, the numbers are all over the place (table below). One flaw in the above analysis is that datasets were used to generate coefficients in the regression equation, and then the regression equation was tested on these same datasets. Less precise: expected pCO2 = [serum bicarbonate) + 15. This indicates a compensatory mechanism attempted . This is because NS contains a supraphysiologic concentration of chloride (154 mEq/L) and no bicarbonate; thus it will raise serum chloride while diluting other anions - namely lowering bicarbonate - inducing a metabolic acidosis. This comes as little surprise. Kraut JA, Madias NE. He is a co-founder of theAustralia and New Zealand Clinician Educator Network(ANZCEN) and is the Lead for theANZCEN Clinician Educator Incubatorprogramme. He is one of the founders of theFOAMmovement (Free Open-Access Medical education) and is co-creator oflitfl.com,theRAGE podcast, theResuscitologycourse, and theSMACCconference. Emerg Med J. Actual HCO3 22 - 26 mEq/L. Our bodies are smart and try to compensate every time something begins to fail. }, #FOAMed Medical Education Resources byLITFLis licensed under aCreative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. 1998;27:387408. We report our findings from a retrospective audit in medical in-patients and the potential benefit of this underused resource. Venous to Arterial Conversion (v-TAC; OBIMedical ApS, Denmark) is a method to calculate ABG values from a VBG and pulse oximetry (SpO2). Pulmonary receptor stimulation (asthma, pneumonia, pulmonary edema, or embolism). For calculation, >12 is generally used as the cutoff for a high AG. Unable to load your collection due to an error, Unable to load your delegates due to an error. clear: left; The accuracy of three methods for interpreting VBG values were tested using this data: Below are the results. I would argue that important management decisions shouldn't be based on subtle differences in ABG or VBG values. Furthermore, central VBG can be used as a useful screening tool for arterial hypercapnia. The hydrogen ion from step 2 binds with hemoglobin H + Hgb => HHgb. MDCalc loves calculator creators researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. This calculator provides all the parameters derived from Stewart's theory of acid-base balance. In the Summary: The Bullet section there is a misprint in the formula for estimating Arterial pCO2. The oxygen consumption cannot be assessed solely on SaO2. Arterial blood gases (ABG) are essential for assessment of patients with severe illness, but sampling is difficult in some settings and more painful than for peripheral venous blood gas (VBG). v-TAC (Venous to Arterial Conversion Method) is a recent technique to obtain calculated ABG values based on a peripheral venous blood gas (VBG) and oximetry from a fingertip (SpO 2 ). pH = pKa + log ( [A-]/ [HA]) pH= 6.1 + log ( [HCO3-]/ (0.03x pCO2) Our blood gas analyzer has the ability to detect the pH and pCO2. In this review you will learn: Normal vs. abnormal blood pH, CO2, HCO3 levels; Basics about the buffering system in acid-base imbalances (ABG) to VBG samples in DKA, but not many comparing the use of values from a VBG vs a . Acute and chronic lung disease through several of the above mechanisms (obstructive sleep apnea, obesity hypoventilation syndrome, COPD, interstitial fibrosis). PMC Structural: pancreatic fistula, villous adenoma. Ann Thorac Med. Most blood gas (BG) analysers calculate iCa, but this is often ignored. Serum anion gap: its uses and limitations in clinical medicine. I must say you have hi quality articles here. ABG values are generally taken as the gold-standard for pH assessment. 2). View Anesthetic and . To investigate further, I requ. To investigate further, I requested post-publication data from several researchers who had published studies comparing ABG vs. VBG data. It is best practice, if not an absolute requirement, to share data now (unless there is a very specific reason not to). I had some ideas for converting VBG values into ABG values. The role of venous blood gas in the emergency department: a systematic review and meta-analysis. 2003 Aug;102(8):539-43. However where there is concern about a respiratory component to an illness, an initial ABG is necessary. Definitely, I will encourage my reader to visit this original article in the beginning of my post. There is a significant difference in the readings presented. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); document.getElementById( "ak_js_2" ).setAttribute( "value", ( new Date() ).getTime() ); We just published a blog on abg vs vbg this morning too, with a derivation for the arterlialization of vbg. The venous blood gas ( VBG) is a multi-component serum assessment of pH, blood gas tensions (P v O 2 and P v CO 2 ), bicarbonate (HCO 3 ), and the base excess. #mergeRow-gdpr fieldset label { The results displayed in the right side column are those obatined from formulas that take into account the Hb level (not used in the left column). From this baseline, you can then begin to recognise significant variations in a patient's results, which could indicate clinical deterioration. It's due to the fact that there is more acidic carbon dioxide (CO) in the venous blood. 2001 Sep;18(5):340-2. If the AG and HCO3 are balanced, (HCO3 5mmol/L AG), there is no concurrent metabolic process. Performing a VBG rather than an ABG is particularly convenient in the intensive care unit, since most patients have a central venous catheter from which venous blood can be quickly and easily obtained. Considered as more accurate. Is the result of the ABG going to change my diagnosis or treatment? Where BSA (body surface area) is calculated from patient height and weight, based on Haycock formula: BSA = 0.024265 x (Height in cm) 0.3964 x (Weight in kg) 0.5378. The obtained blood gas sample should be delivered to the laboratory as soon as possible. A systematic review and meta-analysis. Arterial blood gases are blood taken from an artery, normally the radial artery, which . This calculator only differentiates between acute (pH abnormal) and compensated (pH normal). It should be Venous pCO2 0.2(93-Venous O2 saturation). Copyright 2021 International Anesthesia Research Society. 70 years. Expected pCO2 = 0.7([HCO3] - 24) + 40 2. = 0.9287 (HCO 3 - 24.4 + 14.83 (pH - 7.4)). Recently, he showed up at the ER (Emergency room), presenting fatigue and shortness of breath.