ABG Study Questions

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

A. Kidneys and Lungs Rationale: 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.

Decreased plasma bicarbonate (HCO3-): A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis

A. Metabolic Acidosis Rationale: 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.

A patient who is comatose is admitted to the hospital with an unknown history. Respirations are deep and rapid. Arterial blood gas levels on admission are pH, 7.20; PaCO2, 21 mm Hg; PaO2, 92 mm Hg; and HCO3-, 8. You interpret these laboratory values to indicate: A. Metabolic acidosis B. Metabolic alkalosis C. Respiratory acidosis D. Respiratory alkalosis

A. Metabolic acidosis The low pH indicates acidosis. The low PaCO2 is caused by the hyperventilation, either from primary respiratory alkalosis (not compatible with the measured pH) or as a compensation for metabolic acidosis. The low HCO3- indicates metabolic acidosis or compensation for respiratory alkalosis (again, not compatible with the measured pH). Thus metabolic acidosis is the correct interpretation.

CV 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, PaO2 120 mm Hg, PaCO2 31 mm Hg, and HCO3 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

A. Respiratory Alkalosis, Uncompensated Rationale: The primary disorder is acute respiratory alkalosis (low CO2) due to the pain and anxiety causing her to hyperventilate. There has not been time for metabolic compensation.

The major effect of acidosis is overexcitement of the central nervous system: A. True B. False C. Both Acidosis and Alkalosis result in overexcitement of the central nervous system.

A. True Rationale: 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.

A 2-year-old child was brought into the emergency department after ingesting several morphine tablets from a bottle in his mother's purse. The nurse knows that the child is at greatest risk for which acid-base imbalance? a) Respiratory acidosis b) Respiratory alkalosis c) Metabolic acidosis d) Metabolic alkalosis

ANS: A Morphine overdose can cause respiratory depression and hypoventilation. Hypoventilation results in retention of CO2 and respiratory acidosis. Respiratory alkalosis would result from hyperventilation, causing a decrease in CO2 levels. Metabolic acid-base imbalance would be a result of kidney dysfunction, vomiting, diarrhea, or other conditions that affect metabolic acids.

The nurse is caring for a diabetic patient in renal failure. Which laboratory findings would the nurse expect? a) pH 7.3, PaCO2 36 mm Hg, HCO3- 19 mEq/L b) pH 7.5, PaCO2 35 mm Hg, HCO3- 35 mEq/L c) pH 7.3, PaCO2 47 mm Hg, HCO3- 23 mEq/L d) pH 7.35, PaCO2 40 mm Hg, HCO3- 25 mEq/L

ANS: A Patients in renal failure develop metabolic acidosis. The laboratory values that reflect this are pH 7.3, PaCO2 36 mm Hg, HCO3- 19 mEq/L. A laboratory finding of pH 7.5, PaCO2 35 mm Hg, HCO3- 35 mEq/L is metabolic alkalosis. pH 7.3, PaCO2 47 mm Hg, HCO3- 23 mEq/L is respiratory acidosis. pH 7.35, PaCO2 40 mm Hg, HCO3- 25 mEq/L values are within normal range.

A patient has the following arterial blood gas (ABG) results: pH 7.32, PaO2 88 mm Hg, PaCO2 37 mm Hg, and HCO3 16 mEq/L. The nurse interprets these results as a. metabolic acidosis. b. metabolic alkalosis. c. respiratory acidosis. d. respiratory alkalosis.

ANS: A The pH and HCO3 indicate that the patient has a metabolic acidosis. The ABGs are inconsistent with the other responses.

A patient was admitted for a bowel obstruction and has had a nasogastric tube set to low intermittent suction for the past 3 days. The patient's respiratory rate has decreased to 12 breaths per minute. The nurse would expect the patient to have which of the following arterial blood gas values? a) pH 7.78, PaCO2 40 mm Hg, HCO3- 30 mEq/L b) pH 7.52, PaCO2 48 mm Hg, HCO3- 28 mEq/L c) pH 7.35, PaCO2 35 mm Hg, HCO3- 26 mEq/L d) pH 7.25, PaCO2 47 mm Hg, HCO3- 29 mEq/L

ANS: B Compensated metabolic alkalosis should show alkalosis pH and HCO3- (metabolic) values, with a slightly acidic CO2 (compensatory respiratory acidosis). In this case, pH 7.52 is alkaline (normal = 7.35 to 7.45), PaCO2is acidic (normal 35 to 45 mm Hg), and HCO3- is elevated (normal = 22 to 26 mEq/L). A result of pH 7.78, PaCO2 40 mm Hg, HCO3- 30 mEq/L is uncompensated metabolic alkalosis. pH 7.35, PaCO2 35 mm Hg, HCO3- 26 mEq/L is within normal limits. pH 7.25, PaCO2 47 mm Hg, HCO3- 29 mEq/L is compensated respiratory acidosis.

The nurse would not expect full compensation to occur for which acid-base imbalance? a) Respiratory acidosis b) Respiratory alkalosis c) Metabolic acidosis d) Metabolic alkalosis

ANS: B Usually the cause of respiratory alkalosis is a temporary event (e.g., an asthma or anxiety attack). The kidneys take about 24 hours to compensate for an event, so it is unlikely to see much if any compensation for respiratory alkalosis. Respiratory acidosis usually results from longer-term conditions such as chronic lung disease, narcotic overdose, or another event that causes respiratory depression. The kidneys still do not respond for about 24 hours, but usually the event is still occurring. For both metabolic imbalances, the respiratory system is quick to attempt to compensate: however, it may have difficulty sustaining that compensation.

A patient with a lower respiratory infection has pH of 7.25, PaCO2 of 55 mm Hg, and HCO3- of 20 mEq/L. The physician has been notified. Which is the priority nursing intervention for this patient? a) Check the color of the patient's urine output. b) Place the patient in Trendelenburg position. c) Encourage the patient to increase respirations. d) Place the patient in high Fowler's position.

ANS: C The patient has respiratory acidosis from CO2 retention. Increasing rate and depth of respiration will allow the patient to blow off excess carbon dioxide, and this will begin to correct the imbalance. Checking the urine color is not a necessary assessment. The Trendelenburg position likely would make it more difficult for the patient to breathe and should be avoided. Placing the patient in high Fowler's position may make the patient more comfortable, but it is not necessary.

Which laboratory value should the nurse examine when evaluating uncompensated respiratory alkalosis? a) PaO2 b) Anion gap c) PaCO2 d) HCO3-

ANS: C Uncompensated respiratory imbalances are seen in the PaCO2 levels. PaO2 indicates oxygen status. Anion gap is used for metabolic acidosis. HCO3- is used to evaluate compensation for respiratory imbalances or uncompensated metabolic imbalances.

A patient who has required prolonged mechanical ventilation has the following arterial blood gas results: pH 7.48, PaO2 85 mm Hg, PaCO2 32 mm Hg, and HCO3 25 mEq/L. The nurse interprets these results as a. metabolic acidosis. b. metabolic alkalosis. c. respiratory acidosis. d. respiratory alkalosis.

ANS: D The pH indicates that the patient has alkalosis and the low PaCO2 indicates a respiratory cause. The other responses are incorrect based on the pH and the normal HCO3.

MW, 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, PaCO2 37 mmHg and HCO3 30 mEq/L. What is your assessment? A. Metabolic Acidosis, Uncompensated B. Metabolic Alkalosis, Uncompensated C. Respiratory Alkalosis, Uncompensated D. Metabolic Alkalosis, Partially Compensated

B. Metabolic Alkalosis, Uncompensated Rationale: The postoperative client's ABG results show that he has metabolic alkalosis because of an increased pH and HCO3. It is uncompensated due to the normal PaCO2 which is within 35 to 45 mmHg.

A 3 y.o. ♂ 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, PaCO2 72 mmHg and HCO3 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

B. Respiratory Acidosis, Fully Compensated Rationale: 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 PaCO2 which is acidic and increased HCO3 which is basic.

GK 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, 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, PaCO2 68 mm Hg, HCO3 28 mmol/L, and PaO2 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

B. Respiratory Acidosis, Partially Compensated Rationale: The patient has respiratory acidosis (raised carbon dioxide) resulting from an acute exacerbation of chronic obstructive pulmonary disease, with partial compensation.

MJ, 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, PaCO2 70 mm Hg and HCO3 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

B. Respiratory Acidosis, Uncompensated Rationale: The results show that Mrs. Johansson has respiratory acidosis because of decreased pH and increased PaCO2 which mean acidic in nature. Meanwhile, it is uncompensated because HCO3 is within the normal range.

The nurse would not expect full compensation to occur for which acid-base imbalance? A. Respiratory acidosis B. Respiratory alkalosis C. Metabolic acidosis D. Metabolic alkalosis

B. Respiratory alkalosis Usually the cause of respiratory alkalosis is a temporary event (e.g., an asthma or anxiety attack). The kidneys take about 24 hours to compensate for an event, so it is unlikely to see much if any compensation for respiratory alkalosis. Respiratory acidosis usually results from longer-term conditions such as chronic lung disease, narcotic overdose, or another event that causes respira-tory depression. The kidneys still do not respond for about 24 hours, but usually the event is still occurring. For both metabolic imbalances, the respiratory system is quick to attempt to compensate: however, it may have difficulty sustaining that compensation.

Baby LR 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, PaCO2 27 mmHg and HCO3 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

C. Metabolic Acidosis, Fully Compensated Rationale: The infant has metabolic acidosis due to decreased HCO3 and slightly acidic pH. Her pH value is within the normal range which made the result fully compensated.

Increased plasma bicarbonate (HCO3-): A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis

C. Metabolic Alkalosis Rationale: 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.

A 71 y.o ♀ has been 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, PaO2 85 mm Hg, PaCO2 40 mm Hg, and HCO3 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

C. Metabolic Alkalosis, Uncompensated Rationale: The primary disorder is uncompensated metabolic alkalosis (high HCO3 -). As CO2 is the strongest driver of respiration, it generally will not allow hypoventilation as compensation for metabolic alkalosis.

AP, was drinking a glass of wine when she syncopized and hit her head. Her friend dials "911" because AP is unconscious, with depressed ventilation (shallow and slow respirations), rapid heart rate, and is profusely bleeding from both ears. Which primary acid-base imbalance is AP at risk for if medical attention is not provided? A. Metabolic Acidosis B. Metabolic Alkalosis C. Respiratory Acidosis D. Respiratory Alkalosis

C. Respiratory Acidosis Rationale: 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 MgSO4 toxicity are also risk factors of respiratory acidosis.

CZ 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, PaCO2 22 mmHg and HCO3 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

C. Respiratory Alkalosis, Uncompensated Rationale: The results show that the pt has respiratory alkalosis since there is an increase in the pH value and a decrease in PaCO2 which are both basic. It is uncompensated due to the normal HCO3 which is within 22-26 mEq/L.

MJ, an 8 y.o. ♂, 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, PaO2 90 mm Hg, PaCO2 23 mm Hg, and HCO3 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

D. Metabolic Acidosis, Partially Compensated Rationale: The patient was diagnosed having diabetes mellitus. The results show that he has metabolic acidosis (low HCO3 -) with respiratory compensation (low CO2).

High plasma PaCO2: A. Metabolic Acidosis B. Respiratory Alkalosis C. Metabolic Alkalosis D. Respiratory Acidosis

D. Respiratory Acidosis Rationale: 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.

When analyzing an arterial blood gas report of a pt with COPD & respiratory acidosis, the nurse anticipates that compensation will develop through which of the following mechanisms? a) The kidneys retain bicarbonate. b) The kidneys excrete bicarbonate. c) The lungs will retain carbon dioxide. d) The lungs will excrete carbon dioxide.

a) The kidneys retain bicarbonate.

Which of the following may occur with respiratory acidosis? a. Increased intracranial pressure b. Mental alertness c. Decreased pulse d. Decreased blood pressure

a. Increased intracranial pressure

A nurse notes that a client's arterial blood gas results reveal a pH of 7.50 and a PCO2 of 30 mm Hg. The nurse monitors that client for which clinical manifestations associated with these ABG results? Select all the apply. a. Nausea b. Confusion c. Bradypnea d. Tachycardia e. Hyperkalemia f. Lightheadedness

a. Nausea b. Confusion d. Tachycardia f. Lightheadedness

A client in the emergency department reports that he has been vomiting excessively for the past 2 days. His arterial blood gas analysis shows a pH of 7.50, PaCO2 of 43 mm Hg, PaO2 of 75 mm Hg, and HCO3− of 42 mEq/L. Based on these findings, the nurse documents that the patient is experiencing which type of acid-base imbalance? a) Respiratory alkalosis b) Metabolic alkalosis c) Respiratory acidosis d) Metabolic acidosis

b) Metabolic alkalosis

A nurse is caring for a client who is on a mechanical ventilator. Blood gas results indicate a pH of 7.50 and a PCO2 of 30 mm Hg. The nurse has determined that the client is experiencing respiratory alkalosis. Which laboratory value would most likely be noted in this condition? a. Sodium level of 145 mEq/L b. Potassium level of 3 mEq/L c. Magnesium level of 2 mg/dL d. Phosphorus level of 4 mg/dL

b. Potassium level of 3 mEq/L

A nurse reviews the arterial blood gas results of a client and notes the following: pH 7.45, PCO2 of 30 mm Hg, and HCO3 of 22 mEq/L. The nurse analyzes these results as indicating which condition? a. Metabolic acidosis, compensated b. Respiratory alkalosis, compensated c. Metabolic alkalosis, uncompensated d. Respiratory acidosis, uncompensated

b. Respiratory alkalosis, compensated

The client's ABGs on room air are: pH 7.33, PaO2 77, HCO3 23. The nurse would instruct the client to: a. Try to breathe more slowly b. Used the bedside inspirometer hourly when awake. c. Where nasal cannula oxygen at 6 L/min. d. Increase fluid intake to flush the kidneys.

b. Used the bedside inspirometer hourly when awake.

When evaluating arterial blood gases (ABGs), which value is consistent with metabolic alkalosis? a. PaCO2 36 b. pH 7.48 c. HCO3 21 mEq/L d. O2 sat 95%

b. pH 7.48

The nurse is caring for a pt who is anxious & dizzy following a traumatic experience. The arterial blood gas findings include: pH 7.48, PaO2 110, PaCO2 25, & HCO3 24. The nurse would anticipate which initial intervention to correct this problem? a) Immediately administer oxygen via a mask & monitor oxygen saturation. b) Prepare to start an intravenous fluid bolus using isotonic fluids. c) Encourage the pt to breathe in & out slowly into a paper bag. d) Anticipate the administration of intravenous sodium bicarbonate.

c) Encourage the pt to breathe in & out slowly into a paper bag.

The 30 year old client with asthma is brought into the emergency department by a friend because of difficulty breathing throughout the day and is now confused. The client's ABGs are: pH 7.19, PaO2 46, PaCO2 88, HCO3 25. The nurse would anticipate that the client's immediate treatment will be directed at. a. increasing O2 via nasal cannula to maintain pulse oximetry saturation greater than 94% b. Starting IV with Solu-Medrol c. Intubation and mechanical ventilation d. Administration of STAT bronchodilator via handheld nubulizer

c. Intubation and mechanical ventilation

A pt's blood gases show a pH greater of 7.53 & bicarbonate level of 36 mEq/L. The nurse realizes that the acid-base disorder this pt is demonstrating is which of the following? a) respiratory acidosis b) metabolic acidosis c) respiratory alkalosis d) metabolic alkalosis

d) metabolic alkalosis

A client with a 3-day history or nausea and vomiting presents to the emergency department. Arterial blood gases are drawn and the nurse reviews the results, expecting to note which of the following? a. A decreased pH and an increased CO2 b. An increased pH and a decreased CO2 c. A decreased pH and a decreased HCO3- d. An increased pH with an increase HCO3-

d. An increased pH with an increase HCO3-

Which of the following would be a potential cause for respiratory acidosis? a. Diarrhea b. Vomiting c. Hyperventilation d. Hypo-ventilation

d. Hypo-ventilation

A client with emphysema has the following blood gas values: PCO2 35, PO2 78, and pH 7.40. The nurse's action should be to: a. Give O2 at 1L immediately for hypoxia. b. Take no action, these values are normal for the condition. c. Tell the client to breathe slower. d. Question the report and call the physician.

d. Question the report and call the physician.

A client who is found unresponsive has arterial blood gases drawn and the results indicate the following: pH is 7.12, PCO2 is 90 mm Hg, and HCO3- is 22 mEq/L. The nurse interprets the results as indicating which condition? a. Metabolic acidosis with compensation b. Respiratory acidosis with compensation c. Metabolic acidosis without compensation d. Respiratory acidosis without compensation

d. Respiratory acidosis without compensation