Arterial blood gas determinations of pco2 provide the most accurate determinations of the adequacy of alveolar ventilation, but capillary, transcutaneous, and end. Arterial blood can be obtained from an artery in your wrist, arm, or groin, or preexisting arterial line if. The paramedics arrived after 10 minutes, during which cpr had not been attempted. An arterial blood gas abg test measures the amounts of arterial gases, such as oxygen and carbon dioxide. Arterial blood gas interpretation the arterial blood gas provides the following values. The oxygen tension pao 2, carbon dioxide tension paco. It is possible to have a mixed respiratory and metabolic disorder that makes interpretation of an arterial blood gas result difficult. Analysis of arterial blood gases abg is an essential investigation in the management of critically ill patients as it provides important information about alveolar ventilation, oxygenation, and acidbase balance measurement of abg includes measurement of three parameters, i. In context of oral and maxillofacial surgery, arterial blood gas analysis plays a vital role in monitoring of postoperative patients, patients receiving oxygen therapy, those on. Decide whether to proceed with the test if a contraindication is present on the basis of how urgent the sample is. The partial pressure of oxygen in arterial blood pao2 refers to pressure exerted by. Interpretation of blood gas and acidbase data julia h.
Most contraindications are relative and rarely encountered. The hypothesis is that during acute severe asthma, air flow rates are determined mostly by properties of large airways, whereas gas exchange, specifically vq mismatch abnormalities, depends on airway narrowing andor. Riley, bvsc, ms before discussing clinical cases we would like to present a brief recent history of developments in the area of acidbase and bloodgas analysis so some appreciationofthe efforts of those who have worked to simplify measurement techniques and clarify clinical. Weve created this guide, which aims to provide a structured approach to abg interpretation whilst also increasing your understanding of each results relevance.
Oxygenation of blood through gas exchange in the lungs. Some blood gas analyzers also measure the methemoglobin, carboxyhemoglobin, and hemoglobin levels. Resting arterial p o 2 does not correlate with exercise capacity. Learner is encouraged to pause video and attempt interpretation before watching the explanation. May 23, 20 consider doing a venous gas much of the important blood gas information can be elicited from a venous blood gas and it is much less painful if you are going to do a blood gas dont have multiple attempts in the same spot if you initially fail either get someone else to try or consider trying the femoral artery, brachial artery or. The radial artery on the wrist is most commonly used to obtain the sample. Blood is drawn anaerobically from a peripheral artery radial, brachial, femoral, or dorsalis pedis via a single percutaneous needle puncture, or from an indwelling arterial cannula or catheter for multiple samples. Carbon dioxide co2 elimination through respiration. Alternatively, subtract the last two digits of the ph e. Learners are encouraged to pause the video, attempt the examples, then replay to see the answer. Simple algorithm of arterial blood gas analysis to ensure consistent, correct and quick responses. In cases where blood gas values do not fall into any of the above classifications, an answer unable to determine will appear when using the interpreter. Arterial blood gas abg sampling oxford medical education.
Nov 15, 20 this 4th video works through abg examples using the ph, paco2 and hco3. Therefore, a basic understanding of how to interpret abg results can be useful for pharmacists to help them clarify the clinical picture. Arterial blood gas interpretation medical books free. Arterial blood gas interpretation, abg analysis, rules for rapid abg analysis, anion gap, approach to mixed disorders introduction arterial blood gas abg analysis is an essential part of diagnosing and managing a patients oxygenation status and acidbase balance. Know some of the indications and contraindications for performing an arterial puncture. A higher than normal paao2 means the lungs are not transferring oxygen properly from alveoli into the. The interpretation of arterial blood gases australian. Nov 02, 2011 interpretation of the arterial blood gas analysis 1. Interpreting and using the arterial blood gas analysis.
Differences are subtle but important on venous gas. A blood gas test requires the collection of a small sample of blood. Before the arterial blood gas test, they may apply pressure to the arteries in your wrist for several seconds. 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. Arterial blood gas abg analysis plays a pivotal role in the management of critically ill patients. The chinese university of hong kong sampling of arterial blood for blood gas analysis will yield information on.
Abg interpretation a guide to understanding abgs geeky. How to interpret arterial blood gas results correspondence. An arterial line in an appropriate patient is likely to save the patient victim of venepuncture multiple painful needles in the ed and during their hospital stayconsider doing a venous gas much of the important blood gas information can be elicited from a venous blood gas and it is much. When one thinks of abg analysis, oxygenation may come to mind first. We may be presented increasingly with venous blood gases 2. It is simple, perhaps simplistic, but it will hopefully arm the reader with the tools and confidence to make better sense of abg results in future. However, the more complicated and in some ways more important part of abg analysis is ph regulation. Here youll get an excellent overview and a stepwise approach to interpret abg analysis. Mar 18, 2020 interpretation of arterial blood gas analysis seems complicated. Interpret the oxygenation state of a patient using the reported arterial blood gas pao2 value. In case of delay, the sample should be placed in ice and such iced sample can be processed upto 2 hours without affecting the blood gas values. An abg test requires that a small volume of blood be drawn from the radial artery with a syringe and a thin needle, but sometimes the femoral artery in the groin or another site is used. Body temperature can also affect arterial blood gas tensions. This helpful, practical book begins with a clear explanation of acidbase balance, followed by a straightforward sixstep approach to arterial blood gas interpretation.
Apr 03, 2020 an arterial blood gas requires the nurse to collect a small sample of blood generally, a full 1 ml. Mistakes in arterial blood gas abg interpretation are common in clinical practice. Interpretation of the arterial blood gas analysis 1. Arterial blood gas abg interpretation is something many medical students find difficult to grasp weve been there. Understanding acidbase balance and interpreting arterial blood gas. Arterial blood provides more information than venous blood with regard to acidbase and oxygenation status. Arterial blood gas analysis is not used for impairment rating purposes on a routine basis. The analysis of arterial blood gas values abgs can detect the presence and identify the causes of acidbase and oxygenation disturbances. Arterial blood gases indications and interpretation. Arterial blood gas interpretation felicia ratnaraj internal medicine pgy 3 pm report.
The blood can also be drawn from an arterial catheter. The results of abg testing will often influence the treatment that patients receive. Interpretation of arterial blood gas article pdf available in indian journal of critical care medicine 142. Arterial blood gas analysis is an important routine investigation to monitor the acidbase balance of patients, effectiveness of gas exchange, and the state of their voluntary respiratory control. Arterial blood gas abg analysis is a crucial part of diagnosing and managing a patients state of oxygenation, ventilation as well as acidbase balance. Arterial blood gas analysis this article aims to give nurses an understanding of the main gas and acidbase measurements derived from an arterial sample, so that they can interpret results of samples from patients in their care. This 4th video works through abg examples using the ph, paco2 and hco3. An arterialblood gas abg test measures the amounts of arterial gases, such as oxygen and carbon dioxide. Interpretation of thearterial blood gas analysis dm seminar dr. Components of the arterial blood gas the arterial blood gas provides the following values. Overview of thediscussion basics of acidbase balance. Oxygen content o2ct, oxygen saturation sao2, and bicarbonate hco3 values are also measured. Interpreting and using the arterial blood gas analysis lian, jin xiong bsn, rn, cns nursing critical care.
The procedure, called the modified allen test, checks that blood flow to your hand is. Describe at least 6 factors that can interfere with arterial blood gas values. The following is a simplified explanation of abgs, including a practical method for interpreting results. Interpreting an arterial blood gas abg is a crucial skill for physicians, nurses, respiratory. Although no randomized controlled study has ever been performed evaluating the benefit of abg analysis in the intensive care unit icu, it is likely this technology stands alone as the diagnostic test which has had the greatest impact on the management of critically ill patients. How to interpret an arterial blood gas analysis lecturio. Interpretation of arterial blood gases abgs david a. The body operates efficiently within a fairly narrow range of blood ph acidbase balance. However, the femoral artery and brachial artery can be used if necessary. Woodruff, msn, rnbc, cns, cmsrn, cen 6 easy steps to. The blood gas components value from mixed venous blood and arterial blood is nearly the same except for oxygen pressure po 2 and saturation so 2. Identify the relationship between oxygen saturation and pao2 as it relates to the oxyhemoglobin dissociation curve. Jan 26, 2015 other useful information from arterial blood gases. Arterial blood gas sampling the society for acute medicine.
Stepbystep approach to arterial and venous blood gas analysis step 1. This is relevant in febrile or hypothermic patients, so body temperature should be recorded at the time of collection. Maier md, msph, in murray and nadels textbook of respiratory medicine sixth edition, 2016. Even relatively small changes can be detrimental to cellular function.
Arterial blood bas abg procedure and interpretation. Blood can be drawn via an arterial stick from the wrist, groin, or above the elbow. Spirometry and arterial blood gases in acute severe asthma. Each gram of haemoglobin can combine, under ideal conditions, with. Following are the steps one should follow when reading the arterial blood gas and interpreting the values simultaneously.
Combine the information from the ph, paco2 and the bicarbonate determine the. Remember there is always the other arm where the test could be performed. Arterial blood gas interpretation hemoglobin breathing. As it is unable to combine with oxygen and it also decreases the oxygen carrying. Remember there is always the other arm where the test could be. This workshop is intended as a basic introduction to arterial blood gas interpretation. Consider an arterial line early in the ed stay if the patient is really sick.
Your doctor may run a blood gas analysis or arterial blood gas abg test if you are showing the signs of an oxygen, carbon dioxide, or ph imbalance such as confusion or difficulty breathing. As a result, arterial hypoxemia at rest is, by itself, not evidence of severe. Arterial blood gas interpretation felicia ratnaraj internal medicine pgy 3. Abg interpretation a guide to understanding abgs geeky medics. Basic physiological concepts, anion gap, respiratory acidosis, metabolic alkalosis, metabolic acidosis. Monitoring of acidbase balance is done by testing patients arterial blood gases abgs. If it outside range, then it is uncompensated or partially compensated. Simple algorithm of arterial blood gas analysis to ensure consistent, correct and. It provides a measure of oxygen diffusion across the alveoli into the blood.
Be able to demonstrate the technique for performing an arterial puncture. Arterial blood gas an overview sciencedirect topics. The authors then apply this approach to a wide range of realistic case studies that resemble situations readers are likely to encounter in practice. Arterial blood gas interpretation abg arterial blood gas analysis is used to measure the partial pressures of oxygen pao2, carbon dioxide paco2, and the ph of an arterial blood sample. The wide range of oxygenation values between arterial and venous blood is the reason why the peripheral venous blood is never used to measure the patients status of oxygenation, table 3 6. 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. Simple algorithm of arterial blood gas analysis to ensure. Interpretation of arterial blood gas pubmed central pmc. Interpreting arterial blood gas abg tests can be an important if not. An abg is a blood test that measures the acidity, or ph, and the levels of oxygen o2 and carbon dioxide co2 from an artery the test is used to check the function of the patients lungs and how well they are able to move oxygen into the blood and remove carbon dioxide. Arterial blood gas analysis workshop learning outcomes at the end of this workshop candidates should be able to. Arterial blood gas analysis workshop page 4 of 8 arterial blood gas analysis workshop scenario 1 initial information a 75 year old man presents to the accident and emergency department after a witnessed out of hospital vf cardiac arrest. Interpret the results of various arterial blood gas samples. 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.
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