As i said previously, for purposes of interpretation we should consider normal ph absolute 7. Jan 26, 2015 arterial blood gases abgs are an important routine investigation to monitor the acidbase balance of patients. Interpretation of arterial blood gases abgs david a. The other lab data can also help determine if the results of the abg are an early or later stage and determine the path of care. List the types of samples that can be analyzed for blood gas and analyte concentrations. Out of these results the anesthesiologists will then prescribe further treatment for the. Started in 1995, this collection now contains 6769 interlinked topic pages divided into a tree of 31 specialty books and 732 chapters. Pdf arterial blood gases abg results reflect underlying pathology and interpretation of the results are often. A lecture discussing the phenomenon of physiologic compensation for derangements of acidbase balance, and how to use an understanding of. To make things simple, i will only refer to the three basic abg values in this post. Arterial blood gas interpretation demystified physician assistant. If the patient is unstable, manual ventilation with a bag. Arterial blood gas abg analysis plays a pivotal role in the management of critically ill patients.
Arterial blood gas analysis is an essential part of diagnosing and managing a patients oxygenation status and acidbase balance. Abg interpretation steps to abg interpretation step 1. The results also help you monitor your patients response to treatment. It is simple, perhaps simplistic, but it will hopefully arm the reader with the tools. Analyze the ph the first step in analyzing abgs is to look at the ph. More practice with abgs contains additional information about integrating base excess and anion gap with your interpretation of abgs, and about correlating abg findings with. Abg interpretation a guide to understanding abgs geeky medics.
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. Abg quick interpretation parameter acidosis normal alkalosis reflects ph 7. The cause of the acidosis is the p a co 2, which is the respiratory component of the abg results. In this article, the basic physiology behind abg analysis and a stepwise approach to. Discuss causes and treatments of respiratory acidosis, respiratory alkalosis, metabolic. 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. Refer to the chart above listing the normals for ph.
Without treatment metabolic acidosis will become progressively worse. Lets look at abg values, and what the abg measures. Treatment is not going to depend solely on the abg. If your patient is mechanically ventilated, good abg interpretation skills can guide clinicians in adjusting the ventilator settings to meet the patients needs. Treatment of any of these imbalances should be directed at correcting the. Some blood gas analyzers also measure the methemoglobin, carboxyhemoglobin, and hemoglobin levels. The following is a simplified explanation of abgs, including a practical method for interpreting results. Arterial blood gases abg can be difficult and confusing to understand at first. Sometimes a patient with a low ph can avoid intubation based on this data. Study 19 abg interpretation and treatment flashcards from gina s. Blood gas and critical care analyte analysis chapter objectives 1.
The most important points when assessing a patient are the history, examination and basic observations. If you want to put your abg interpretation skills to the test, check out our abg quiz. Pdf arterial blood gas analysis is a common investigation in emergency. Body will not overcompensate when it comes to acidbase balance so. Using a fourstep approach to abg interpretation can identify an acidbase disorder quickly and accurately so you can intervene appropriately.
Abgs are often used in conjunction with other tests to check how well the lungs are able to move oxygen into the blood and remove carbon dioxide from the blood. This guide provides a structured approach to abg interpretation, including several worked examples to put your interpretation skills to the test. That makes the interpretation of these abg results is uncompensated respiratory acidosis. Interpretation of arterial blood gases requires a systematic assessment of oxygenation, ph, standard bicarbonate shco 3. Explain the types of errors that can occur with blood gas analysis. Clinical examination a comprehensive collection of clinical examination osce guides that include stepbystep images of key steps, video demonstrations and pdf mark schemes. Arterial blood gas analysis is a common investigation in emergency departments and intensive care units for monitoring patients with acute respiratory failure. By the time your test comes up you should be an abg interpretation expert.
When one thinks of abg analysis, oxygenation may come to mind first. Abg interpretation abg analysis arterial blood gases acidbase balance. Interpreting an arterial blood gas abg is a crucial skill for physicians, nurses, respiratory. Aug 28, 2011 treatment is not going to depend solely on the abg. Abgs made easy for nurses w tic tac toe method for arterial blood gas interpretation duration. Continuous regular abg monitoring and recording for trends. In order to easily solve arterial blood gas problems, the tic tac toe method is the best way for doing this. Arterial blood gas sampling society for acute medicine. Interpretation of arterial blood gas pubmed central pmc. Abg interpretation is especially important in critically ill patients. Life in the fast lane litfl is an emergency medicine and critical care medical education blog with ecg library, clinical cases and critical care compendium. Abg interpretation free download as powerpoint presentation. The usefulness of this diagnostic tool is dependent.
Jan 31, 2012 a lecture discussing the phenomenon of physiologic compensation for derangements of acidbase balance, and how to use an understanding of compensation to identify the presence of mixed acidbase. However, general guidelines include correcting the fluid balance and electrolyte status. Acidbase balance overview the ph is a measurement of the acidity or alkalinity of the blood. This is so that what i term the primary ph displacement can be clearly identified without confusion or issues of. A primer on arterial blood gas analysis family medicine residency.
Arterial blood gas abg interpretation for medical students, osces and mrcp paces this section presents how to interpret arterial blood gases. The utilization of an abg analysis becomes necessary in view of the following advantages. 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. Here are ten new and exciting abgs to help you practice. With the relationships and factors above firmly in mind, lets look at some abg results. A fresh and simple approach to interpreting abg is provided. But it is often encountered that many students dont know how to read abg, and thats why we are providing arterial blood gas. Use the following guidelines to interpret these results. Interpretation of the arterial blood gas emergencypedia. British thoracic society 1997 guidelines for the management of chronic. Determine the cause of the acidosis or alkalosis by looking at the pco2 and hco3if ph abg results. Arterial blood gases indications and interpretation. This primer describes a clinical approach to interpreting arterial blood gases. Interpreting an arterial blood gas abg is a crucial skill for physicians, nurses, respiratory therapists, and other health care personnel.
However, its a crucial skill for nurses, physicians, respiratory therapists, and nursing students to learn. Treatment is then aimed at stabilising the initialpresenting problem as well the acidbase status. Historically, clinical laboratory testing was performed by medical laboratory scientists and medical laboratory technicians. Gas chapter 6 blood gas and critical care analyte analysis. While the analyzer can often help with analysis, the history of the patient is critical for accurate interpretation. Sodium and chloride are required for anion gap calculation. This abg practice quiz has 10 questions that will test your knowledge about metabolic and respiratory disorders. An abg is the most accurate representation of a patients clinical status and correct interpretation can lead to quicker and more accurate changes in the. Treatment of metabolic acidosis is variable depending on the cause and whether it is acute or chronic. Life in the fast lane litfl emergency medicine blog. Mistakes in arterial blood gas abg interpretation are common in clinical practice. Abg analysis is a diagnostic test that helps you assess the effectiveness of your patients ventilation and acidbase balance. The best way to get good at abg analysis is to practice. This analyzer should not substitute for clinical context.
Pdf blood gas analysis for bedside diagnosis researchgate. To see how to perform an arterial blood gas check out our guide here. They may help make a diagnosis, indicate the severity of a condition and help to assess treatment. Arterial blood gas abg interpretation for medical students. The pf ratio ratio between the pao 2 and the inspired oxygen concentration expressed as a fraction is a useful guide to the presence and severity of impaired. In addition, you will be tested on if the disorder is partially compensated or uncompensated based on the lab values. Abg analysis provides several test results, but only three are essential for. If your patient is mechanically ventilated, good abg interpretation skills can guide clinicians in adjusting the ventilator. Abg interpretation a guide to understanding abgs geeky. The real value of an abg comes from its ability to provide a nearimmediate reflection of the physiology of your patient, allowing you to recognise and treat pathology more rapidly. It explains each component in turn followed by clinical examples to work through. However, the more complicated and in some ways more important part of abg analysis is ph regulation. The following sixstep process helps ensure a complete interpretation of every abg. Arterial blood gases abg results reflect underlying pathology and interpretation of the results are often compounded by ongoing disease processes and clinical interventions.
Identify normal arterial blood gas values and interpret the meaning of abnormal values. When the ph is normal, it will be fully compensated. 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. 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. If both the pco2 and hco3 are abnormal, the one which deviates most from the norm is most likely causing an. Analysis of arterial blood gases a comprehensive approach japi. Monitor gas exchange and ventilation in response to interventions or therapy. Abg analysis is an indispensable test for critically ill patients or patients treated in an icu.
Apr 10, 2015 abg interpretation is as easy as remembering four basic questions, and then answering them in sequence. 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. Determine the cause of the acidosis or alkalosis by looking at the pco2 and hco3if ph pdf file. Of course then youll have to practice, practice, practice. An arterial blood gas abg test measures the acidity ph, levels of oxygen, and carbon dioxide in arterial blood. The anion and osm gap must be considered when it comes to acidosis.
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