Abgs provide information about acidbase balance and the levels of o2 and co2 in the blood. An arterial blood gas requires the nurse to collect a small sample of blood generally, a full 1 ml. To determine the paco 2, pao 2, hco 3, and sao 2 % values for a young population without lung disease in a city located at an average altitude of 1605m above sea level and a bp of 624 mm hg. Two studies within the last decade3,4 have published reference. Some blood gas analyzers also measure the methemoglobin, carboxyhemoglobin, and hemoglobin levels. Interpreting and using the arterial blood gas analysis. Jan 26, 2015 arterial blood gases abgs are an important routine investigation to monitor the acidbase balance of patients.
The interpretation of arterial blood gases australian. The radial artery on the wrist is most commonly used to obtain the sample. Chemistry test value comments bicarbonate total co2 values for arterial blood gases in the elderly are based on convenience samples or extrapolation of values in younger age groups, and therefore are not necessarily representative of the general lunghealthy, elderly population. Unlike other blood tests, which are either high or low, abgs present the doctor with six numbers that need to be interpreted as one result. However, the femoral artery and brachial artery can be used if necessary. These ranges vary from lab to lab and depend upon the elevation above sea level. But it is often encountered that many students dont know how to read abg, and thats why we are providing arterial blood gas. Arterial blood gas analysis is a common investigation in emergency departments and intensive care units for monitoring patients with acute respiratory failure.
When interpreting arterial blood gas abg results, it is essential to know what abg values are considered normal. Abg interpretation a guide to understanding abgs geeky. Monitoring of acidbase balance is done by testing patients arterial blood gases abgs. Prediction of arterial blood gas values from venous blood. The most common abg abnormalities detected relate to an excess of acid. Arterial blood gas analysis and acidbase balance disorders. Arterial blood gas samples can be obtained from a number of sites, including the following radial artery at the wristthe most popular site for arterial blood sampling because of its easy accessibility, superficial location, and availability of collateral circulation. Interpreting abgs arterial blood gases made easy ausmed. While abg specimens should be analysed immediately for optimal results the clinical and laboratory standards institute. Interpreting an arterial blood gas abg is a crucial skill for physicians, nurses, respiratory therapists, and other health care personnel.
The normal values listed herecalled a reference rangeare just a guide. Arterial blood gas primer clinical respiratory diseases. A method for calculation of arterial blood gas values from measurements in the peripheral blood vtac. Arterial blood gas abg interpretation for medical students, osces and mrcp paces. The normal values noted herecalled a recommendation rangeare just a guide. Arterial blood gases abgs critical lab values medical estudy. Arterial blood gases abgs lab and diagnostic procedure. Emergency department blood gas utilization and changes in. We may be presented increasingly with venous blood gases 2. Arterial blood gas normal values and interpretation by dr.
Correlation of simultaneously obtained capillary, venous, and. Components of the arterial blood gas the arterial blood gas provides the following values. Your lab may have a different range for whats normal. Veterinary normal values blood gas canine feline arterial venous arterial venous. Abg parameters, reference range and alert values reported by the authors lab. Explain the types of errors that can occur with blood gas analysis.
Arterial blood gas in young adults at an average altitude of. Blood for an abg test is taken from an artery whereas most other blood tests are done on a sample of blood taken from a vein. Arterial blood gas abg analysis is an essential part of diagnosing and managing a patients oxygenation status and acidbase balance. Arterial blood gases you are a new staff member working in the emergency department ed during your induction you are introduced to the practical workings of the point of care arterial blood gas abg machine in the ed. This information indicates a patients acidbase balance, the effectiveness of their gas exchange and the state of their ventilatory. Arterial blood gas analysis is used to measure the ph and the partial pressures of oxygen and carbon dioxide in arterial blood. Arterial blood gas analysis assesses a patients partial pressure of. Correlation of arterial blood gas measurements with venous. Low values high values blood gas arterial blood gas, adult ph 7.
The purpose of the present study was to obtain pao2 values from a large. National recommendations on behalf of the croatian society of medical biochemistry and laboratory medicine april 2017 lora dukic 1,2 1croatian society of medical biochemistry and laboratory medicine, committee for the scientific professional development, working group for blood gas testing. Arterial blood gas determinations of pco2 provide the most accurate determinations of the adequacy of alveolar ventilation, but capillary, transcutaneous, and end tidal techniques are also useful. An arterial blood gas abg test measures oxygen and carbon dioxide levels in your blood. A method for calculation of arterial blood gas values. An arterial blood gas abg is a test that measures the oxygen tension pao 2, carbon dioxide tension paco 2, acidity ph, oxyhemoglobin saturation sao 2, and bicarbonate hco 3 concentration in arterial blood. Each hemoglobin molecule contains four atoms of iron and therefore can combine with four molecules of oxygen. Blood gas and critical care analyte analysis chapter objectives 1. Arterial blood gases abgs critical lab values medical.
It explains each component in turn followed by clinical examples to work through. Arterial blood gas in young adults at an average altitude. A blood gas test requires the collection of a small sample of blood. The investigation is relatively easy to perform and yields information that can guide the management of acute and chronic illnesses. Analysis of arterial blood gases a comprehensive approach japi.
While there is some evidence that venous and arterial ph, p co 2, and hco 3 may have sufficient agreement as to be clinically comparable in a variety of clinical settings, the venous blood gas vbg obtained from a central line should be considered a surrogate for arterial blood gas abg only in very specific clinical circumstances. Arterial blood gases indications and interpretation. Arterial blood gas abg interpretation is something many medical students find difficult to grasp weve been there. Oct 05, 2019 arterial blood gas analysis abg, is a test that measures the amount of oxygen o2 and carbon dioxide co2 in the blood, as well as the acidity ph of the blood. Arterial blood gas analysis provides information on the following. An arterial blood gas abg test measures the acidity ph and levels of oxygen and carbon dioxide in the blood. Discuss arterial blood gas values and their implications to patient management. The present article is an attempt for the simplified approach for the bedside interpretation of abg. Patients are often required to be checked for arterial blood gas analysis to find what exactly is happening in the body of patients system. Oct 15, 2017 many other blood tests are done on a sample of blood taken from a vein, after the blood has actually already gone through the bodys tissues where the oxygen is used up and carbon dioxide is produced. Apr 03, 2020 an arterial blood gas requires the nurse to collect a small sample of blood generally, a full 1 ml. From this baseline, you can then begin to recognise significant variations in a patients results, which could indicate clinical deterioration.
This was a multicenter, prospective, observational study of subjects ventilated in the emergency department, conducted at 3 academic emergency departments from july 2011 to march 20. While there is some evidence that venous and arterial ph, pco2, and hco3 may have sufficient agreement as to be clinically comparable in a variety of clinical settings, the venous blood gas. With the increasing number of elderly people in developed countries, physicians are often confronted with patients whose arterial oxygen tension, pao2, is lower than that of normal young adults. It measures the acidity ph and the levels of oxygen and carbon dioxide in arterial blood. This section presents how to interpret arterial blood gases. Weve created this guide, which aims to provide a structured approach to abg interpretation whilst also increasing your understanding of each results relevance. It is, therefore, important that students and physicians be able to interpret the results of arterial blood gas sampling, determine the patients acidbase status and assess the adequacy of oxygenation. When the ph is normal, it will be fully compensated. Samples from the pulmonary artery are however, more accurate and can only be performed if the patient has a pa catheter. Arterial blood gases abg results reflect underlying pathology and interpretation of the results are often compounded by ongoing disease processes and clinical interventions.
This primer describes a clinical approach to interpreting arterial blood gases. Practices related to processing of blood gas samples are not standardized in the. Arterial blood gases abg results reflect underlying pathology and interpretation of the results are often. The most important points when assessing a patient are the history, examination and basic observations. Many other blood tests are done on a sample of blood taken from a vein, after the blood has actually already gone through the bodys tissues where the oxygen is used up and carbon dioxide is produced. The following sixstep process helps ensure a complete interpretation of every abg. As you struggle to listen to the machine company representative talking about cleaning the machine. The analysis of arterial blood gases abg plays a pivotal role in making correct diagnosis. Abg results may indicate decreased o2 levels hypoxia, decreased or increased co2 levels hypo or hypercapnia, acidosis decreased ph, alkalosis increased ph. Arterial blood gas is usually advised to patients suffering from respiratory illnesses or under critical care. Interpretation of arterial blood gas pubmed central pmc.
The ph is a measurement of the acidity or alkalinity of the blood. Blood gas analysis is a commonly used diagnostic tool to evaluate the partial. Therefore, a basic understanding of how to interpret abg results can be useful for pharmacists to help them clarify the clinical picture. Prediction of arterial blood gas values from venous blood gas values in patients with acute exacerbation of chronic obstructive pulmonary disease. An arterial blood gas abg analysis can tell you about a patients oxygenation, acidbase balance, pulmonary function, and metabolic status. Considering the ease of venous blood sample collection, it would be preferred over aterial sampling if a blood gas value determined by venous blood gas analysis could be used to reveal patients acidbase status and had the same accuracy for patient management as that of arterial sampling. Veterinary normal values blood gas canine feline arterial venous arterial venous ph 7. As pao2 increases, more oxygen diffuses into the red blood cells, where it combines with hemoglobin to form oxyhemoglobin.
The normal values predicted in the literature for very old individuals are generally extrapolated from younger subjects. Arterial blood gas abg values provide information about acidbase statusunderlying cause of imbalancebodys ability to regulate phoverall oxygen status if not respiratory issue, they can draw venous. An arterial blood gas, or abg for short, is a test that measures the blood levels of oxygen pao2, carbon dioxide paco2, and acidbase balance ph in the body. Several studies have shown good correlation between capillary blood, venous blood, and arterial blood gas values. Mar 26, 2018 arterial blood gas is usually advised to patients suffering from respiratory illnesses or under critical care. Following are the steps one should follow when reading the arterial blood gas and interpreting the values simultaneously.
Arterial blood gases in elderly persons with chronic. For example, they cant tell whether low levels are caused by lung or heart problems. Its a test that is used to assess how well oxygen is being distributed throughout the body and how well carbon dioxide is being removed. Existing reference values for arterial blood gases in the elderly are based on convenience samples or extrapolation of values in younger age groups, and therefore are not necessarily representative of the general lunghealthy, elderly population. The results of abg testing will often influence the treatment that patients receive.
Arterial blood gas abg values alone dont provide enough information to diagnose a problem. It also measures your bodys acidbase ph level, which is usually in balance when youre healthy. If it outside range, then it is uncompensated or partially compensated. They may help make a diagnosis, indicate the severity of a condition and help to assess treatment.
What are the most common arterial blood gas abnormalities. Some abg results also show hemoglobin and serum electrolyte values. Details about i ph ii oxygenation, oxygen saturation, oxygen content, alveolar gas equation, indices of oxygenation iii carbon dioxide transport, pco 2 total co 2 content, and bicarbonate levels iv base excess and buffer base 5. Arterial blood gas abg interpretation for medical students, osces and mrcp paces this section presents how to interpret arterial blood gases. Arterial blood gas reference values vary as a result of altitude changes associated with barometric pressure bp. How to interpret arterial blood gas results correspondence. This approach also has clinical implications as collecting arterial blood gas values is essential for monitoring and treating highrisk clinical patients for respiratory and acidbase status 17. Table i represents the ph values and corresponding. Arterial blood gas test normal values shows values for ph, oxygen, carbon dioxide, bicarbonates, lactic acid levels and oxygen saturation. Arterial blood gases abgs are measured in a laboratory test to determine the extent of compensation by the buffer system.
Arterial blood gas an overview sciencedirect topics. Arterial blood gas sampling society for acute medicine. Differences are subtle but important on venous gas. The learner will be able to describe the process for umbilical cord blood collection. Chemistry test value comments bicarbonate total co2 40 mmoll bilirubin, total 15 mgdl. Reference values for arterial blood gases in the elderly.
If capillary sample 100150 micro l is being taken from prewarmed heel, let the capillary fill from the tissue site from where blood is oozing out figure i. This indispensable tool helps you assess and monitor critically ill patients in the icu or other critical care settings. It is an essential part of diagnosing and managing a patients oxygenation status and acidbase balance. Aarc clinical practice guideline blood gas analysis and. Stepbystep approach to arterial and venous blood gas analysis step 1. Arterial blood gas abg interpretation for medical students. Blood can be drawn via an arterial stick from the wrist, groin, or above the elbow. This information indicates a patients acidbase balance, the effectiveness of their. Arterial blood gas analysis abg, is a test that measures the amount of oxygen o2 and carbon dioxide co2 in the blood, as well as the acidity ph of the blood. Arterial blood gas measurement is an essential quick test in clinical practice to evaluate oxygenation and for the identification and diagnosis of acidbase and metabolic disorders. Cohb and methemoglobin methb,17 and other calculated or derived values such as plasma bicarbonate and base excessdeficit.
List the types of samples that can be analyzed for blood gas and analyte concentrations. Arterial blood can be obtained from an artery in your wrist, arm, or groin, or preexisting arterial line if you are currently. Given that this can be difficult, there is a need for a simple algorithm for systematically handling each of the numbers in turn, as discussed below. Pdf arterial blood gases abg results reflect underlying pathology and interpretation of the results are often compounded by ongoing.
The usefulness of this diagnostic tool is dependent on being able to correctly interpret the results. Arterial blood gases values normal ranges and procedure. Arterialised capillary samples are comparable to arterial blood table i. We measured the rate of arterial blood gas abg and venous blood gas vbg analysis, and we assessed the associations between the conditions of hypoxemia, hyperoxia, hypercapnia, or.
407 1258 385 669 1117 1014 39 1219 531 90 1571 1155 1034 255 527 200 1095 405 733 1392 534 1585 1552 484 921 1053 1063 1023 930 141 1091 880 462 975 20 553 862