What is the normal range for blood gases?
Blood gas analysis, also called arterial blood gas analysis (ABG analysis), helps measure
- The concentration of oxygen and carbon dioxide gases in the blood (measured in terms of partial pressure).
- The pH of the blood, revealing how acidic or alkaline the blood is.
- The levels of bicarbonate ions in the blood.
- The oxygen saturation or SaO2 that tells what percentage of hemoglobin (the pigment in the red blood cells) is saturated with oxygen.
ABG analysis is a popular procedure. It can also be done at the patient’s bedside. The test involves a rapid analysis of the parameters. Thus, it is an important tool used by doctors to plan and modify the treatment of their patients. It may be especially useful for a patient who is critically ill such as those with heart diseases, kidney diseases or uncontrolled diabetes. The test can reveal whether the exchange of gases is occurring properly in the body. This can reflect any abnormalities in the lungs, heart, kidneys or metabolism.
The normal values for various parameters measured through ABG analysis are as follows
| Parameter | Value |
| Partial pressure of oxygen (PaO2) | 75-100 mmHg* |
| Partial pressure of carbon dioxide (PaCO2) | 38-42 mmHg* |
| pH of arterial blood | 7.38-7.42 |
| Oxygen saturation (SaO2) | 94-100% |
| Bicarbonate concentration (HCO3) | 22-28 mEq/L* |
*mmHg means millimeters of mercury
**mEq/L stands for milliequivalents per liter
These values represent the ABG analysis done at the sea levels. The values may differ with a change in altitude. There may also be variations in the readings obtained from two different laboratories. Therefore, clinical correlation is necessary.
Why is a blood gas analysis done?
The blood carries dissolved gases such as oxygen and carbon dioxide. Oxygen is added to the blood when it travels through the lungs, whereas the waste gas from the tissues (carbon dioxide) is removed from the blood. The balance of these gases also influences the pH of the blood. Thus, arterial blood gas (ABG) analysis may be performed to diagnose various health conditions that may affect the lungs, heart and kidneys. These medical conditions may manifest as a change in the oxygen saturation, carbon dioxide levels or pH of the blood.
ABG analysis can be used for diagnosing
- Diseases of the lungs such as asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.
- Kidney failure.
- Diabetes complications such as diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS).
- Severe infections or septicemia.
- Drug overdose.
- Poisoning.
- Heart failure.
- Hemorrhage.
- Shock.
Arterial blood sampling may also be done to see the patient’s response to the treatment. It also tells the doctor whether the patient needs supplemental oxygen or other support for breathing.
How is a blood gas analysis performed?
The arterial blood gas (ABG) analysis is a quick procedure that can be done in the outpatient department or by the patient’s bedside (point-of-care test). The patient does not need to prepare for this test.
During the test
The healthcare professional will clean the site from where the blood will be drawn with an antiseptic solution.
Generally, the blood is withdrawn from an artery. The blood is generally withdrawn from the wrist (radial artery), although the groin (femoral artery) or arm (brachial artery) arteries may also be used.
After the antiseptic solution has dried, the professional will insert a small needle through the skin into the artery. The patient may feel a pinching sensation as the needle is introduced into the skin. The professional may use a numbing medicine before introducing the needle to minimize discomfort.
Generally, 1 mL of the blood is withdrawn.
After withdrawing the blood, pressure is applied to the site for a few minutes to stop the bleeding.
The sample will be quickly sent to the laboratory for analysis.
SLIDESHOW
COPD Foods to Boost Your Health - COPD Diet Tips See SlideshowHealth Solutions From Our Sponsors
UCSF Benioff Children's Hospital San Francisco
Top What Is the Normal Range for Blood Gases Related Articles
Asthma in Children
Asthma in children manifests with symptoms such as coughing and wheezing. Rates of asthma in children are increasing. Asthma in children is usually diagnosed based on the description of symptoms. Lung function tests may also be used. A variety of medications are used for the treatment of childhood asthma.
Asthma
Asthma is a condition in which hyperreactive airways constrict and result in symptoms like wheezing, coughing, and shortness of breath. Causes of asthma include genetics, environmental factors, personal history of allergies, and other factors. Asthma is diagnosed by a physician based on a patient's family history and results from lung function tests and other exams. Inhaled corticosteroids (ICS) and long-acting bronchodilators (LABAs) are used in the treatment of asthma. Generally, the prognosis for a patient with asthma is good. Exposure to allergens found on farms may protect against asthma symptoms.
What Is Asthma? Symptoms, Causes, and Treatments
What is asthma? What is the main cause of asthma? Learn information about asthma, a chronic disease of the bronchiole tubes. Discover information about asthma attacks, complications of asthma, and how to control an asthma attack.
Brain Hemorrhage
A brain hemorrhage is a type of stroke caused when an artery bursts in the brain, causing localized bleeding in the surrounding tissue. Causes of brain hemorrhage include aneurysm, liver disease, brain tumor, head trauma, high blood pressure, and blood vessel abnormalities. Symptoms and signs include sudden severe headache, nausea, vomiting, loss of balance, tingling, numbness, vision changes, loss of consciousness, and loss of fine motor skills. Treatment depends upon the cause, location, and size of the brain hemorrhage.
Congestive Heart Failure (CHF): Symptoms, Causes, Stages, Treatment
Congestive heart failure (CHF) refers to a condition in which the heart loses the ability to function properly. Heart disease, high blood pressure, diabetes, myocarditis, and cardiomyopathies are just a few potential causes of congestive heart failure. Signs and symptoms of congestive heart failure may include fatigue, breathlessness, palpitations, angina, and edema. Physical examination, patient history, blood tests, and imaging tests are used to diagnose congestive heart failure. Treatment of heart failure consists of lifestyle modification and taking medications to decrease fluid in the body and ease the strain on the heart. The prognosis of a patient with congestive heart failure depends on the stage of the heart failure and the overall condition of the individual.
COPD (Chronic Obstructive Pulmonary Disease)
COPD or chronic obstructive pulmonary disease is a lung condition caused by smoking tobacco, exposure to secondhand smoke, and/or air pollutants. Conditions that accompany COPD include chronic bronchitis, chronic cough, and emphysema.Symptoms of COPD include shortness of breath, wheezing, and chronic cough. Treatment of COPD includes GOLD guidelines, smoking cessation, medications, and surgery. The life expectancy of a person with COPD depends on the stage of the disease.
COPD Quiz
COPD is a combination of three conditions? Take this quiz to learn the three conditions that make up the pulmonary disease called chronic obstructive pulmonary disease (COPD).
COPD Lung Symptoms
COPD is a pulmonary disorder caused by obstructions in the airways of the lungs leading to breathing problems. Learn about COPD symptoms, diagnosis, and treatment options.
COPD vs. Asthma (Differences and Similarities)
COPD (chronic obstructive pulmonary disease) and asthma both have common symptoms like coughing, wheezing, shortness of breath, and a tight feeling in the chest. COPD is caused by tobacco smoking, while asthma is caused by your inherited genetic makeup and their interactions with the environment. Risk factors for asthma are obesity, exposure to cigarette smoke (even secondhand smoke), and personal history of hay fever. There is no cure for either disease, but symptoms can be managed with medication. A person with asthma has a better prognosis and life expectancy than someone with COPD.
COPD vs. Emphysema
COPD (chronic obstructive pulmonary disease) is the term doctors and other healthcare professionals use to describe a group of serious, progressive (worsens over time), chronic lung diseases that include emphysema, chronic bronchitis, and sometimes asthma. The number one cause of COPD or emphysema, is smoking, and smoking is the third leading cause of death in the US.
Heart Failure: Causes, Signs, Stages, and Treatment
Heart failure (congestive) is caused by many conditions including coronary artery disease, heart attack, cardiomyopathy, and conditions that overwork the heart. Symptoms of heart failure include congested lungs, fluid and water retention, dizziness, fatigue and weakness, and rapid or irregular heartbeats. There are two types of congestive heart failure, systolic or left-sided heart failure; and diastolic or right-sided heart failure. Treatment, prognosis, and life-expectancy for a person with congestive heart failure depends upon the stage of the disease.
Shock (Medical)
What is shock? A life-threatening condition with symptoms like low blood pressure, weakness, shallow breathing, clammy skin, fainting, anxiety, confusion, and chest pain. Learn about causes, types, and treatment.
What Is the Life Expectancy of Someone With COPD?
Chronic obstructive pulmonary disease (COPD) is a group of diseases with the chief symptom of breathlessness and cough. COPD is a slowly progressive disease. Depending on the disease severity, the five-year life expectancy for people with chronic obstructive pulmonary disease (COPD) ranges from 40%-70%. That means 40-70 out of 100 people will be alive after five years of diagnosis of COPD.