ABG Test Questions
1. George Kent is a 54 year old widower with a history of chronic obstructive pulmonary disease and was rushed to the emergency department with increasing shortness of breath, pyrexia, and a productive cough with yellow-green sputum. He has difficulty in communicating because of his inability to complete a sentence. One of his sons, Jacob, says he has been unwell for three days. Upon examination, crackles and wheezes can be heard in the lower lobes; he has a tachycardia and a bounding pulse. Measurement of arterial blood gas shows pH 7.3, PaCÓ 68 mm Hg, HCǑ 28 mmol/L, and PaÓ 60 mm Hg. How would you interpret this? A. Respiratory Acidosis, Uncompensated B. Respiratory Acidosis, Partially Compensated C. Metabolic Alkalosis, Uncompensated D. Metabolic Acidosis, Partially Compensated
1. Answer: B. Respiratory Acidosis, Partially Compensated The patient has respiratory acidosis (raised carbon dioxide) resulting from an acute exacerbation of chronic obstructive pulmonary disease, with partial compensation.
10. Anne, who is drinking beer at a party, falls and hits her head on the ground. Her friend Liza dials "911" because Anne is unconscious, depressed ventilation (shallow and slow respirations), rapid heart rate, and is profusely bleeding from both ears. Which primary acid-base imbalance is Anne at risk for if medical attention is not provided? A. Metabolic Acidosis B. Metabolic Alkalosis C. Respiratory Acidosis D. Respiratory Alkalosis
10. Answer: C. Respiratory Acidosis One of the risk factors of having respiratory acidosis is hypoventilation which may be due to brain trauma, coma, and hypothyroidism or myxedema. Other risk factors include COPD, Respiratory conditions such as pneumothorax, pneumonia and status asthmaticus. Drugs such as Morphine and MgSÒ toxicity are also risk factors of respiratory acidosis.
11. Dave, a 6-year-old boy, was rushed to the hospital following her mother's complaint that her son has been vomiting, nauseated and has overall weakness. After series of tests, the nurse notes the laboratory results: potassium: 2.9 mEq. Which primary acid-base imbalance is this boy at risk for if medical intervention is not carried out? A. Respiratory Acidosis B. Respiratory Alkalosis C. Metabolic Acidosis D. Metabolic Alkalosis
11. Answer: D. Metabolic Alkalosis Vomiting, hypokalemia, overdosage of NaHCǑ and NGT suctioning are considered risk factors of metabolic alkalosis.
12. An old beggar was admitted to the emergency department due to shortness of breath, fever, and a productive cough. Upon examination, crackles and wheezes are noted in the lower lobes; he appears to be tachycardic and has a bounding pulse. Measurement of arterial blood gas shows pH 7.2, PaCÓ 66 mm Hg, HCǑ 27 mmol/L, and PaÓ 65 mm Hg. As a knowledgeable nurse, you know that the normal value for pH is: A. 7.20 B. 7.30 C. 7.40 D. 7.50
12. Answer: C. 7.40 Normal blood pH must be maintained within a narrow range of 7.35-7.45 to ensure the proper functioning of metabolic processes and the delivery of the right amount of oxygen to tissues. Acidosis refers to an excess of acid in the blood that causes the pH to fall below 7.35, and alkalosis refers to an excess of base in the blood that causes the pH to rise above 7.45.
13. Liza's mother is seen in the emergency department at a community hospital. She admits that her mother is taking many tablets of aspirin (salicylates) over the last 24-hour period because of a severe headache. Also, the mother complains of an inability to urinate. The nurse on duty took her vital signs and noted the following: Temp = 97.8 °F; apical pulse = 95; respiration = 32 and deep. Which primary acid-base imbalance is the gentleman at risk for if medical attention is not provided? A. Respiratory Acidosis B. Respiratory Alkalosis C. Metabolic Acidosis D. Metabolic Alkalosis
13. Answer. C. Metabolic Acidosis Salicylate overdose causes a high anion gap metabolic acidosis in both children and adults. Adults commonly develop a mixed acid-base disorder as a respiratory alkalosis due to direct respiratory centre stimulation occurs as well. This second disorder is uncommon in children.
14. A patient who is hospitalized due to vomiting and a decreased level of consciousness displays slow and deep (Kussmaul breathing), and he is lethargic and irritable in response to stimulation. The doctor diagnosed him of having dehydration. Measurement of arterial blood gas shows pH 7.0, PaÓ 90 mm Hg, PaCÓ 22 mm Hg, and HCǑ 14 mmol/L; other results are Na+ 120 mmol/L, K+ 2.5 mmol/L, and Cl- 95 mmol/L. As a knowledgeable nurse, you know that the normal value for PaCÓ is: A. 22 mm Hg B. 36 mm Hg C. 48 mm Hg D. 50 mm Hg
14. Answer: B. 36 mm Hg The normal range for PaCÓ is from 35 to 35 mm Hg.
15. A company driver is found at the scene of an automobile accident in a state of emotional distress. He tells the paramedics that he feels dizzy, tingling in his fingertips, and does not remember what happened to his car. Respiratory rate is rapid at 34/minute. Which primary acid-base disturbance is the young man at risk for if medical attention is not provided? A. Respiratory Acidosis B. Respiratory Alkalosis C. Metabolic Acidosis D. Metabolic Alkalosis
15. Answer: B. Respiratory Alkalosis Hyperventilation is typically the underlying cause of respiratory alkalosis. Hyperventilation is also known as overbreathing. When someone is hyperventilating, they tend to breathe very deeply or very rapidly.
16. An elderly client was admitted to hospital in a coma. Analysis of the arterial blood gave the following values: PCÓ 16 mm Hg, HCǑ- 5 mmol/L and pH 7.1. As a well-rounded nurse, you know that the normal value for HCǑ is: A. 20 mmol/L B. 24 mmol/L C. 29 mmol/L D. 31 mmol/L
16. Answer: B. 24 mmol/L The normal value for bicarbonate (HCǑ) is 22-26 mmol/L or mEq/L. It may vary slightly among different laboratories. The given values show the common measurement range of results for these tests. Some laboratories use different measurements or may test different specimens.
17. In a patient undergoing surgery, it was vital to aspirate the contents of the upper gastrointestinal tract. After the operation, the following values were acquired from an arterial blood sample: pH 7.55, PCÓ 52 mm Hg and HCǑ- 40 mmol/l. What is the underlying disorder? A. Respiratory Acidosis B. Respiratory Alkalosis C. Metabolic Acidosis D. Metabolic Alkalosis
17. Answer: D. Metabolic Alkalosis NGT suctioning, vomiting, hypokalemia and overdosage of NaHCǑ are considered risk factors of metabolic alkalosis.
18. A mountaineer attempts an assault on a high mountain in the Andes and reaches an altitude of 5000 meters (16,400 ft) above sea level. What will happen to his arterial PCÓ and pH? A. Both will be lower than normal. B. The pH will rise and PCÓ will fall. C. Both will be higher than normal due to the physical exertion. D. The pH will fall and PCÓ will rise
18. Answer: B. The pH will rise and PCÓ will fall. The mountaineer will suffer from a respiratory alkalosis. The decline in the PÓ with altitude will stimulate breathing to offset the hypoxia. Carbon dioxide is driven from the blood faster than it is produced in the tissues so PCÓ falls and pH rises.
19. A young woman is found comatose, having taken an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values: pH 6.90, HCǑ- 13 meq/liter and PaCÓ 68 mmHg. This patient's acid-base status is most accurately described as: A. Metabolic Acidosis B. Respiratory Acidosis C. Simultaneous Respiratory and Metabolic Acidosis D. Respiratory Acidosis with Complete Renal Compensation
19. Answer: C. Simultaneous Respiratory and Metabolic Acidosis Whenever the PCÓ and HCǑ are abnormal in opposite directions, ie, one above normal while the other is reduced, a mixed respiratory and metabolic acid-base disorder exists. When the PCÓ is elevated and the [HCǑ-] reduced, respiratory acidosis and metabolic acidosis coexist.
2. Carl, an elementary student, was rushed to the hospital due to vomiting and a decreased level of consciousness. The patient displays slow and deep (Kussmaul breathing), and he is lethargic and irritable in response to stimulation. He appears to be dehydrated—his eyes are sunken and mucous membranes are dry—and he has a two week history of polydipsia, polyuria, and weight loss. Measurement of arterial blood gas shows pH 7.0, PaÓ 90 mm Hg, PaCÓ 23 mm Hg, and HCǑ 12 mmol/L; other results are Na+ 126 mmol/L, K+ 5 mmol/L, and Cl- 95 mmol/L. What is your assessment? A. Respiratory Acidosis, Uncompensated B. Respiratory Acidosis, Partially Compensated C. Metabolic Alkalosis, Uncompensated D. Metabolic Acidosis, Partially, Compensated
2. Answer: D. Metabolic Acidosis, Partially, Compensated The student was diagnosed having diabetes mellitus. The results show that he has metabolic acidosis (low HCǑ -) with respiratory compensation (low CÓ).
20. A mother is admitted in the emergency department following complaints of fever and chills. The nurse on duty took her vital signs and noted the following: Temp = 100 °F; apical pulse = 95; respiration = 20 and deep. Measurement of arterial blood gas shows pH 7.37, PaÓ 90 mm Hg, PaCÓ 40 mm Hg, and HCǑ 24 mmol/L. What is your assessment? A. Hyperthermia B. Hyperthermia and Respiratory Alkalosis C. Hypothermia D. Hypothermia and Respiratory Alkalosis
20. Answer: A. Hyperthermia An individual is considered to have hyperthermia if he or she has a temperature of >37.5 or 38.3 °C (99.5 or 100.9 °F). Measurement of arterial blood gases are normal.
3. A cigarette vendor was brought to the emergency department of a hospital after she fell into the ground and hurt her left leg. She is noted to be tachycardic and tachypneic. Painkillers were carried out to lessen her pain. Suddenly, she started complaining that she is still in pain and now experiencing muscle cramps, tingling, and paraesthesia. Measurement of arterial blood gas reveals pH 7.6, PaÓ 120 mm Hg, PaCÓ 31 mm Hg, and HCǑ 25 mmol/L. What does this mean? A. Respiratory Alkalosis, Uncompensated B. Respiratory Acidosis, Partially Compensated C. Metabolic Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
3. Answer: A. Respiratory Alkalosis, Uncompensated The primary disorder is acute respiratory alkalosis (low CÓ) due to the pain and anxiety causing her to hyperventilate. There has not been time for metabolic compensation.
4. Ricky's grandmother is suffering from persistent vomiting for two days now. She appears to be lethargic and weak and has myalgia. She is noted to have dry mucus membranes and her capillary refill takes >4 seconds. She is diagnosed as having gastroenteritis and dehydration. Measurement of arterial blood gas shows pH 7.5, PaÓ 85 mm Hg, PaCÓ 40 mm Hg, and HCǑ 34 mmol/L. What acid-base disorder is shown? A. Respiratory Alkalosis, Uncompensated B. Respiratory Acidosis, Partially Compensated C. Metabolic Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
4. Answer: C. Metabolic Alkalosis, Uncompensated The primary disorder is uncompensated metabolic alkalosis (high HCǑ -). As CÓ is the strongest driver of respiration, it generally will not allow hypoventilation as compensation for metabolic alkalosis.
5. Mrs. Johansson, who had undergone surgery in the post-anesthesia care unit (PACU), is difficult to arouse two hours following surgery. Nurse Florence in the PACU has been administering Morphine Sulfate intravenously to the client for complaints of post-surgical pain. The client's respiratory rate is 7 per minute and demonstrates shallow breathing. The patient does not respond to any stimuli! The nurse assesses the ABCs (remember Airway, Breathing, Circulation!) and obtains ABGs STAT! Measurement of arterial blood gas shows pH 7.10, PaCÓ 70 mm Hg and HCǑ 24 mEq/L. What does this mean? A. Respiratory Alkalosis, Partially Compensated B. Respiratory Acidosis, Uncompensated C. Metabolic Alkalosis, Partially Compensated D. Metabolic Acidosis, Uncompensated
5. Answer: B. Respiratory Acidosis, Uncompensated The results show that Mrs. Johansson has respiratory acidosis because of decreased pH and increased PaCÓ which mean acidic in nature. Meanwhile, it is uncompensated because HCǑ is within the normal range.
6. Baby Angela was rushed to the Emergency Room following her mother's complaint that the infant has been irritable, difficult to breastfeed and has had diarrhea for the past 3 days. The infant's respiratory rate is elevated and the fontanels are sunken. The Emergency Room physician orders ABGs after assessing the ABCs. The results from the ABG results show pH 7.39, PaCÓ 27 mmHg and HCǑ 19 mEq/L. What does this mean? A. Respiratory Alkalosis, Fully Compensated B. Metabolic Acidosis, Uncompensated C. Metabolic Acidosis, Fully Compensated D. Respiratory Acidosis, Uncompensated
6. Answer: C. Metabolic Acidosis, Fully Compensated Baby Angela has metabolic acidosis due to decreased HCǑ and slightly acidic pH. Her pH value is within the normal range which made the result fully compensated.
7. Mr. Wales, who underwent post-abdominal surgery, has a nasogastric tube. The nurse on duty notes that the nasogastric tube (NGT) is draining a large amount (900 cc in 2 hours) of coffee ground secretions. The client is not oriented to person, place, or time. The nurse contacts the attending physician and STAT ABGs are ordered. The results from the ABGs show pH 7.57, PaCÓ 37 mmHg and HCǑ 30 mEq/L. What is your assessment? A. Metabolic Acidosis, Uncompensated B. Metabolic Alkalosis, Uncompensated C. Respiratory Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
7. Answer: B. Metabolic Alkalosis, Uncompensated The postoperative client's ABG results show that he has metabolic alkalosis because of an increased pH and HCǑ. It is uncompensated due to the normal PaCÓ which is within 35 to 45 mmHg.
8. Client Z is admitted to the hospital and is to undergo brain surgery. The client is very anxious and scared of the upcoming surgery. He begins to hyperventilate and becomes very dizzy. The client loses consciousness and the STAT ABGs reveal pH 7.61, PaCÓ 22 mmHg and HCǑ 25 mEq/L. What is the ABG interpretation based on the findings? A. Metabolic Acidosis, Uncompensated B. Respiratory Alkalosis, Partially Compensated C. Respiratory Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
8. Answer: C. Respiratory Alkalosis, Uncompensated The results show that client Z has respiratory alkalosis since there is an increase in the pH value and a decrease in PaCÓ which are both basic. It is uncompensated due to the normal HCǑ which is within 22-26 mEq/L.
9. Three-year-old Adrian is admitted to the hospital with a diagnosis of asthma and respiratory distress syndrome. The mother of the child reports to the nurse on duty that she has witnessed slight tremors and behavioral changes in her child over the past four days. The attending physician orders routine ABGs following an assessment of the ABCs. The ABG results are pH 7.35, PaCÓ 72 mmHg and HCǑ 38 mEq/L. What acid-base disorder is shown? A. Respiratory Acidosis, Uncompensated B. Respiratory Acidosis, Fully Compensated C. Respiratory Alkalosis, Fully Compensated D. Metabolic Alkalosis, Partially Compensated
9. Answer: B. Respiratory Acidosis, Fully Compensated The patient has respiratory acidosis (raised carbon dioxide) resulting from asthma and respiratory distress syndrome, with compensation having normal pH value within 7.35to 7.45, increased PaCÓ which is acidic and increased HCǑ which is basic.
25. What two organs in the body serve as a compensatory function to maintain acid base balance? A. Kidneys and Lungs B. Lungs and Spleen C. Heart and Liver D. Gallbladder and Appendix
Answer: A. Kidneys and Lungs The carbonic acid concentration is controlled by the amount of carbon dioxide excreted by the lungs. The bicarbonate concentration is controlled by the kidneys, which selectively retain or excrete bicarbonate in response to the body's needs.
23. Decreased plasma bicarbonate (HCǑ-) A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis
Answer: A. Metabolic Acidosis The body compensates by using body fat for energy, producing abnormal amounts of ketone bodies. In an effort to neutralize the ketones and maintain the acid-base balance of the body, plasma bicarbonate is exhausted. This condition can develop in anyone who does not eat an adequate diet and whose body fat must be burned for energy. Symptoms include headache and mental dullness.
37. pH 7.45, PaCÓ 50, HCǑ- 30 A. Metabolic Alkalosis, Fully Compensated B. Respiratory Alkalosis, Fully Compensated C. Metabolic Alkalosis, Partially Compensated D. Respiratory Acidosis, Partially Compensated
Answer: A. Metabolic Alkalosis, Fully Compensated
38. pH 7.6, PaCÓ 53, HCǑ- 38 A. Metabolic Alkalosis, Partially Compensated B. Metabolic Alkalosis, Fully Compensated C. Respiratory Acidosis, Partially Compensated D. Respiratory Alkalosis, Fully Compensated
Answer: A. Metabolic Alkalosis, Partially Compensated
26. Arterial blood gas (ABG) measurement will give the information needed to determine if the primary disturbance of acid-base balance is respiratory or metabolic in nature. A. True B. False C. Both Carbonic Acid Excess and Deficit Only D. Both Bicarbonate Excess and Deficit Only
Answer: A. True ABG's are blood tests that are useful in identifying the cause and extent of the acid-base disturbance and in guiding and monitoring treatment.
29. The human body functions optimally in a state of homeostasis. A. True B. False C. Maybe D. Homeostasis has nothing to do with metabolic balance.
Answer: A. True The maintenance of acid-base balance, which in one part of homeostasis, is evidenced by an arterial plasma pH value of 7.35-7.45. Many mechanisms in the body work together to achieve and maintain this delicate narrow range of pH that is essential for normal cell function.
28. Alkalosis is characterized by overexcitement of the nervous system. A. True B. False C. The major effect of Alkalosis is a depression of the central nervous system. D. Both Acidosis and Alkalosis result in overexcitement of the central nervous system.
Answer: A. True The muscles may go into a state of tetany and convulsions.
30. Acids have no hydrogen ions and are able to bind in a solution. A. True B. False C. Acid is a substance that is not capable of donating hydrogen ions. D. Acids and bases have nothing to do with hydrogen ions.
Answer: B. False Acids are substances having one or more hydrogen ions that can be liberated into a solution. Bases are substances that can bind hydrogen ions in a solution.
27. The major effect of acidosis is overexcitement of the central nervous system. A. True B. False C. Maybe D. Both Acidosis and Alkalosis result in overexcitement of the central nervous system
Answer: B. False The major effect is a depression of the central nervous system, as evidenced by disorientation followed by coma.
35. pH 7.34, PaCÓ 24, HCǑ- 20 A. Respiratory Acidosis, Partially Compensated B. Metabolic Acidosis, Partially Compensated C. Metabolic Acidosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
Answer: B. Metabolic Acidosis, Partially Compensated
21. Low plasma PaCÓ A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis
Answer: B. Respiratory Alkalosis Excessive pulmonary ventilation decreases hydrogen ion concentration and thus causes respiratory alkalosis. It can become dangerous when it leads to cardiac dysrhythmias caused partly by a decrease in serum potassium levels.
36. pH 7.64, PaCÓ 25, HCǑ- 19 A. Respiratory Acidosis, Uncompensated B. Respiratory Alkalosis, Partially Compensated C. Respiratory Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated
Answer: B. Respiratory Alkalosis, Partially Compensated
33. pH 7.55, PaCÓ 25, HCǑ- 22 A. Respiratory Acidosis, Partially Compensated B. Respiratory Alkalosis, Uncompensated C. Metabolic Alkalosis, Partially Compensated D. Metabolic Acidosis, Uncompensated
Answer: B. Respiratory Alkalosis, Uncompensated
24. Increased plasma bicarbonate (HCǑ-) A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis
Answer: C. Metabolic Alkalosis In metabolic alkalosis, breathing becomes depressed in an effort to conserve carbon dioxide for combination with water in the blood to raise the blood level of carbonic acid. Symptoms include confusion, dizziness, numbness or tingling of fingers or toes.
40. pH 7.4, PaCÓ 59, HCǑ- 35 A. Respiratory Acidosis, Uncompensated B. Metabolic Alkalosis, Uncompensated C. Respiratory Acidosis, Fully Compensated D. Metabolic Alkalosis, Partially Compensated
Answer: C. Respiratory Acidosis, Fully Compensated
32. pH 7.39, PaCÓ 44, HCǑ- 26 A. Respiratory Acidosis B. Metabolic Acidosis C. Respiratory Alkalosis D. Normal
Answer: D. Normal
22. High plasma PaCÓ A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis
Answer: D. Respiratory Acidosis An excess of carbon dioxide (hypercapnia) can cause carbon dioxide narcosis. In this condition, carbon dioxide levels are so high that they no longer stimulate respirations but depress them.
34. pH 7.17, PaCÓ 48, HCǑ- 36 A. Respiratory Acidosis, Uncompensated B. Metabolic Acidosis, Partially Compensated C. Respiratory Alkalosis, Partially Compensated D. Respiratory Acidosis, Partially Compensated
Answer: D. Respiratory Acidosis, Partially Compensated
31. pH 7.57, PaCÓ 22, HCǑ- 17 A. Respiratory Acidosis, Partially Compensated B. Respiratory Alkalosis, Uncompensated C. Metabolic Acidosis, Partially Compensated D. Respiratory Alkalosis, Partially Compensated
Answer: D. Respiratory Alkalosis, Partially Compensated
39. pH 7.5, PaCÓ 19, HCǑ- 22 A. Respiratory Alkalosis, Partially Compensated B. Metabolic Alkalosis, Partially Compensated C. Respiratory Acidosis, Uncompensated D. Respiratory Alkalosis, Uncompensated
Answer: D. Respiratory Alkalosis, Uncompensated
