Acid Base Balance
Insulin deficiency, in association with increased levels of counter-regulatory hormones and dehydration, is the primary cause of:
diabetic ketoacidosis. Explanation: Insulin deficiency, in association with increased levels of counter-regulatory hormones (glucagon, growth hormone, cortisol, catecholamines) and dehydration, is the primary cause of diabetic ketoacidosis (DKA), a life-threatening form of metabolic acidosis that is a frequent complication of diabetes. Liver converts triglycerides (lipolysis) to fatty acids, which in turn change to ketone bodies. The accumulation and excretion of ketone bodies by the kidneys is called ketonuria. Glucosuria is glucose that is spilled into the urine.
A young woman presents with vaginal itching and irritation of recent onset. Her labia are swollen, and she has a frothy yellowish discharge with an unpleasant smell and a pH of 6.8. She has been celibate during the last six months and has been taking antibiotics for a throat infection. Which medication is most likely to clear her symptoms?
metronidazole Explanation: The character of the discharge, lack of recent sexual activity, and current antibiotic treatment point to infection with Trichomonas vaginalis, which can exist asymptomatically and flare up only if conditions, such as an imbalance in normal vaginal flora resulting from antibiotic treatment, enable the protozoan to proliferate. Trichomoniasis responds well to treatment with metronidazole.
A client is receiving supplemental oxygen. When determining the effectiveness of oxygen therapy, which arterial blood gas value is most important?
partial pressure of arterial oxygen (PaO2)
A client admitted with acute anxiety has the following arterial blood gas (ABG) values: pH, 7.55; partial pressure of arterial oxygen (PaO2), 90 mm Hg; partial pressure of arterial carbon dioxide (PaCO2), 27 mm Hg; and bicarbonate (HCO3-), 24 mEq/L. Based on these values, the nurse suspects
respiratory alkalosis. Explanation: This client's above-normal pH value indicates alkalosis. The below-normal PaCO2 value indicates acid loss via hyperventilation; this type of acid loss occurs only in respiratory alkalosis. These ABG values wouldn't occur in metabolic acidosis, respiratory acidosis, or metabolic alkalosis.
A pregnant client reports an increase in a thick, whitish vaginal discharge. Which response by the nurse would be most appropriate?
"This discharge is normal during pregnancy." Explanation: During pregnancy, vaginal secretions become more acidic, white, and thick. Most women experience an increase in a whitish vaginal discharge, called leukorrhea, during pregnancy. The nurse should inform the client that the vaginal discharge is normal except when it is accompanied by itching and irritation, possibly suggesting Candida albicans infection (a monilial vaginitis), which is a very common occurrence in this glycogen-rich environment. Monilial vaginitis is a benign fungal condition and is treated with local antifungal agents. The client need not refrain from sexual activity when there is an increase in a thick, whitish vaginal discharge.
The nurse is caring for a client in active labor who has had a fetal blood sampling to check for fetal hypoxia. The nurse determines that the fetus has acidosis when the pH is:
7.15 or less. Explanation: In the hypoxic fetus, the pH will fall below 7.2, which is indicative of fetal distress.
The nurse is caring for the following group of clients. Select the client most likely to be diagnosed with respiratory alkalosis.
A 26-year-old female with anxiety who has been hyperventilating Explanation: Respiratory alkalosis can occur with hyperventilating and the loss of CO2.The other three clients are more at risk for respiratory acidosis as a result of retaining CO2.
A client with a pulmonary embolus has the following arterial blood gas (ABG) values: pH, 7.49; partial pressure of arterial oxygen (PaO2), 60 mm Hg; partial pressure of arterial carbon dioxide (PaCO2), 30 mm Hg; bicarbonate (HCO3-) 25 mEq/L. What should the nurse do first?
Administer oxygen by nasal cannula as ordered. Explanation: When a pulmonary embolus places a client at risk for oxygen deprivation, the body compensates by hyperventilating. This causes respiratory alkalosis, as reflected in the client's ABG values. However, the most significant ABG value is the PaO2 value of 60 mm Hg, which indicates hypoxemia. To manage hypoxemia, the nurse should increase oxygenation by administering oxygen via nasal cannula as ordered. Instructing the client to breathe into a paper bag would cause depressed oxygenation when the client reinhaled carbon dioxide. Auscultating breath sounds or encouraging deep breathing and coughing wouldn't improve oxygenation.
Which of the following clients is at highest risk for peptic ulcer disease?
Client with blood type O Explanation: Clients with blood type O are more susceptible to peptic ulcers than those with blood types A, B, and AB.
The physician has prescribed 0.9% sodium chloride IV for a hospitalized client in metabolic alkalosis. Which nursing actions are required to manage this client? Select all that apply.
Compare ABG findings with previous results. Maintain intake and output records. Document presenting signs and symptoms. Explanation: Metabolic alkalosis results in increased plasma pH because of accumulated base bicarbonate or decreased hydrogen ion concentrations. The result is retention of sodium bicarbonate and increased base bicarbonate. Nursing management includes documenting all presenting signs and symptoms to provide accurate baseline data, monitoring laboratory values, comparing ABG findings with previous results (if any), maintaining accurate intake and output records to monitor fluid status, and implementing prescribed medical therapy.
The vagina is at risk for infection because of its location and because it opens to the outside of the body. What is a protective mechanism of the vagina to keep it from becoming infected?
Correct response: Normal vaginal pH is acidic (4 to 5), which protects from infection. Explanation: Normally, the vagina maintains an acidic pH of 4 to 5, which protects the vagina from infection.
A client is receiving a diuretic as the first-line treatment of mild hypertension. The nurse monitors the client for signs and symptoms of hypokalemia with which agent?
Hydrochlorothiazide Explanation: Hydrochlorothiazide is a thiazide diuretic that promotes the loss of sodium as well as potassium from the body. Subsequently, the client is at risk for hypokalemia. Amiloride, spironolactone, and triamterene are potassium-sparing diuretics. The client using these diuretics would need to be monitored for hyperkalemia because potassium is not lost along with sodium.
Which is the priority nursing diagnosis for a client undergoing a laryngectomy?
Ineffective airway clearance Explanation: The priority nursing diagnosis is Ineffective airway clearance, utilizing the ABCs. Imbalanced nutrition: Less than body requirement, impaired verbal communication, and anxiety and depression are all potential nursing diagnoses, but the question is asking for the priority nursing diagnosis for this patient. The priority is to identify any issues related to impaired airway.
A patient who has been treated for uric acid stones is being discharged from the hospital. What type of diet does the nurse discuss with the patient?
Low-purine diet Explanation: For uric acid stones, the patient is placed on a low-purine diet to reduce the excretion of uric acid in the urine. Foods high in purine (shellfish, anchovies, asparagus, mushrooms, and organ meats) are avoided, and other proteins may be limited.
The nurse is caring for a client who has excessive diarrhea. Which acid-base disturbance does the nurse anticipate will result from having excessive diarrhea?
Metabolic acidosis Explanation: The client who has diarrhea has increased loss of bicarbonate from the intestinal tract, which results in metabolic acidosis. The pH value would be decreased, and the bicarbonate would be decreased.
The nurse is reviewing the following lab results of a client diagnosed with renal failure:pH: 7.24PCO2: 38 mm Hg (5.05 kPa)HCO3:18 mEq/L (18 mmol/L)The nurse would interpret this as:
Metabolic acidosis Explanation: Metabolic acidosis would be diagnosed based on the findings related to a low pH level (<7.3) and a low bicarbonate level. Respiratory acidosis represents a decreased pH and an increased PCO2, metabolic alkalosis represents an increased pH and a increased HCO3, and respiratory alkalosis represents an increased pH and a decreased PCO2.
A client has the following arterial blood gas (ABG) values: pH, 7.12; partial pressure of arterial carbon dioxide (PaCO2), 40 mm Hg; and bicarbonate (HCO3-), 15 mEq/L. These ABG values suggest which disorder?
Metabolic acidosis Explanation: This client's pH value is below normal, indicating acidosis. The HCO3- value also is below normal, reflecting an overwhelming accumulation of acids or excessive loss of base, which suggests metabolic acidosis. The PaCO2 value is normal, indicating absence of respiratory compensation. These ABG values eliminate respiratory alkalosis, respiratory acidosis, and metabolic alkalosis.
A client is admitted to the unit with a diagnosis of intractable vomiting for 3 days. What acid-base imbalance related to the loss of stomach acid does the nurse observe on the arterial blood gas (ABG)?
Metabolic alkalosis Explanation: Metabolic alkalosis is associated with an excess of HCO3, a decrease in H+ ions, or both, in the extracellular fluid (ECF). This may be the result of excessive acid losses or increased base ingestion or retention. Loss of stomach acid may result in this condition. Metabolic acidosis is a proportionate deficit of bicarbonate in ECF. The deficit can occur as the result of an increase in acid components or an excessive loss of bicarbonate such as in diarrhea. Respiratory acidosis is when the carbon dioxide level is high and the ph is low. Respiratory alkalosis is when the carbon dioxide level is low and the ph is high.
Which arterial blood gas (ABG) values leads the nurse to suspect a client has developed respiratory acidosis? Select all that apply.
PCO2 of 57mm Hg (7.58 kPa) pH 7.32 Explanation: ABGs measure pH, carbon dioxide (PCO2), bicarbonate ion (HCO3-), oxygen pO2, base excess, and the anion gap. A pH that is below 7.35 is considered acidic while above 7.45 is considered alkaline. The PCO2 is considered the primary indicator of respiratory function. Elevation above 45mm Hg (5.99 kPa) indicates acidosis while a decrease below 35mm Hg (4.66 kPa) indicates alkalosis. Bicarbonate (HCO3-) is the primary indicator of metabolic function and is considered alkaline if greater than 26 mEq/L, and acidic if below 22 mEq/L. Base excess measures the level of all the buffer systems in the blood. If the level is more than 0.2 mEq/L above the normal pH of 7.4 it is considered an excess and indicates metabolic alkalosis. Anion gap indicates the difference between plasma concentration of the major measured cation (sodium) and the sum of the measured anions (chloride and bicarbonate). This level rises in conditions of acidosis. Anion gap and base excess or deficit are used primarily to indicate metabolic acid-base disorders.
The nurse is administering an insulin drip to a patient in ketoacidosis. What insulin does the nurse know is the only one that can be used intravenously?
Regular Explanation: Short-acting insulins are called regular insulin (marked R on the bottle). Regular insulin is a clear solution and is usually administered 20 to 30 minutes before a meal, either alone or in combination with a longer-acting insulin. Regular insulin is the only insulin approved for IV use.
A child who has type 1 diabetes mellitus is brought to the emergency department and diagnosed with diabetic ketoacidosis. What treatment would the nurse expect to administer?
Regular insulin Explanation: Insulin for diabetic ketoacidosis is given intravenously. Only regular insulin can be administered by this route.
Arterial blood gases (ABGs) have been drawn on the client. The nurse reviews the results. pH is 7.31 PaO2 92 mm Hg (12.24 kPa) PaCO2 50 mm Hg (6.65 kPa) HCO3 28 mEq/L (28 mmol/L) How will the nurse interpret these ABG results? Select all that apply.
Respiratory acidosis Partial compensation Explanation: To interpret ABGs, the nurse determines if the pH is acidotic or alkalotic. In this case, the pH is 7.31; it is acidotic. Next, the nurse determine if the other values are acidotic or alkalotic. The arterial carbon dioxide (PaCO2) level is 50 mm Hg (6.65 kPa); it is acidotic. The bicarbonate (HCO3) level is 28 mEq/L (28 mmol/L); it is alkalotic. Both the pH and the carbon dioxide levels are acidotic. The cause of this imbalance is respiratory. Thus, the client is experiencing respiratory acidosis. The body is attempting to compensate the imbalance by increasing the bicarbonate. Since all three values are abnormal, partial compensation has occurred. If the pH had been normal, then compensation would have been complete. If no compensation had occurred, then the bicarbonate level would be normal in this set of ABG results.
A male client has cirrhosis and is receiving diuretic therapy. The nurse knows that what drug will help prevent metabolic alkalosis or hypokalemia in this client?
Spironolactone Explanation: For clients with cirrhosis, diuretic therapy should be initiated in a hospital setting, with small doses and careful monitoring. To prevent hypokalemia and metabolic alkalosis, supplemental potassium or spironolactone may be needed.
Which oncologic emergency involves the failure in the negative feedback mechanism that normally regulates the release of antidiuretic hormone (ADH)?
Syndrome of inappropriate antidiuretic hormone release (SIADH) Explanation: SIADH is a result of the failure in the negative feedback mechanism that normally regulates the release of antidiuretic hormone (ADH). Cardiac tamponade is an accumulation of fluid in the pericardial space. DIC is a complex disorder of coagulation and fibrinolysis, which results in thrombosis and bleeding. Tumor lysis syndrome is a rapidly developing oncologic emergency that results from the rapid release of intracellular contents as a result of radiation- or chemotherapy-induced cell destruction of large or rapidly growing cancers such as leukemia.
A client with emphysema is at a greater risk for developing which acid-base imbalance?
chronic respiratory acidosis Explanation: Respiratory acidosis, which may be either acute or chronic, is caused by excess carbonic acid, which causes the blood pH to drop below 7.35. Chronic respiratory acidosis is associated with disorders such as emphysema, bronchiectasis, bronchial asthma, and cystic fibrosis.
