Acid Base PrepU
The nurse is teaching a healthy adult client about adequate hydration. How much average daily intake does the nurse recommend? 1,000 mL/day 1,500 mL/day 2,500 mL/day 3,500 mL/day
Correct response: 2,500 mL/day Explanation: In healthy adults, fluid intake generally averages approximately 2,500 mL/day, but it can range from 1,800 to 3,000 mL/day with a similar volume of fluid loss. 1,000 mL/day and 1,500 mL/day are too low, and 3,500 mL/day is too high.
A client has been diagnosed with metabolic acidosis. What assessment finding does the nurse expect? Increased pH above 7.45 Increased PCO2 above 45 mm/Hg (5.99 kPa) Decreased pH below 7.35 Decreased PCO2 below 35 mm/Hg (4.66 kPa)
Correct response: Decreased pH below 7.35 Explanation: In metabolic acidosis, the client's pH will decrease below 7.35 or normal range. In addition , the client's HCO3- will decrease to below 22 mEq/L (22 mmol/L)
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 An 18-year-old female who has overdosed on narcotics A 63-year-old male with a 40-year history of smoking and chronic lung disease A 45-year-old male with pneumothorax after a car accident
Correct response: 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.
The nurse who is providing care for several clients recognizes which client is at the highest risk for developing an acid-base imbalance? A client who is being treated for acute kidney injury and who requires dialysis A client who had an anaphylactic reaction to an insect sting and required resuscitation A client who is receiving intravenous penicillin for the treatment of primary syphilis A client who has a rectovaginal fistula that will require surgery
Correct response: A client who is being treated for acute kidney injury and who requires dialysis Explanation: Because of the key role that the kidneys play in the maintenance of acid-base balance, individuals with kidney disease are vulnerable to acid-base disorders. Anaphylaxis, syphilis, and fistulas do not present particular risks for acid-base imbalances.
In which client would the nurse be most likely to assess the signs and symptoms of an acid-base imbalance? A client with chronic obstructive pulmonary disease (COPD) whose most recent arterial blood gases reveal a PCO2 of 51 mm Hg A client who has been admitted with a traumatic head injury and whose intracranial pressure is 18 mm Hg A laboring client who is receiving an oxytocin infusion and who has been in the second stage of labor for 7 hours A client with a fluid volume deficit who has been receiving intravenous 0.45% NaCl for over 48 hours
Correct response: A client with chronic obstructive pulmonary disease (COPD) whose most recent arterial blood gases reveal a PCO2 of 51 mm Hg Explanation: An elevated PCO2 is commonly associated with respiratory acidosis because excess CO2 ultimately increases the concentration of H+ ions. Increased intracranial pressure, oxytocin infusion, and the administration of hypotonic fluids are not directly linked to common alterations in acid-base balance.
What is the lab test commonly used in the assessment and treatment of acid-base balance? Complete blood count Basic metabolic panel Arterial blood gas Urinalysis
Correct response: Arterial blood gas Explanation: ABGs are used to assess acid-base balance. The pH of plasma indicates balance or impending acidosis or alkalosis. The complete blood cell count measures the components of the blood, focusing on the red and white blood cells. The urinalysis assesses the components of the urine. Basic metabolic panel (BMP) assess kidney function (BUN and creatinine), sodium and potassium levels, and blood glucose level.
What assessment would a nurse expect to find when caring for a client with metabolic acidosis? Select all that apply. Decreased level of consciousness Warm and flushed skin Increased cardiac output Increased urine acidity Constipation
Correct response: Decreased level of consciousness Warm and flushed skin Increased urine acidity Explanation: Conditions that cause acidosis suppress neural excitability, so as the condition progresses, clients become lethargic, stuporous, or comatose. Skin may be warm and flushed because surface blood vessels are less responsive to sympathetic signals to constrict. Cardiac output will decrease as the heart is less responsive to sympathetic signals. The kidneys increase excretion of hydrogen ions, increasing the urine acidity. The gastrointestinal tract may respond with anorexia, nausea and vomiting.
The nurse is caring for a client with acute primary respiratory acidosis. When determining the cause of the acidosis the nurse is aware that which imbalance is most common? Decreased CO2 retention Increased metabolic acids Renal bicarbonate retention Impaired alveolar ventilation
Correct response: Impaired alveolar ventilation Explanation: Acute respiratory acidosis is frequently caused by impaired alveolar ventilation with CO2 retention. Increased metabolic acids, such as lactic acid, are characteristic of metabolic acidosis. Bicarbonate retention is a compensatory response to respiratory acidosis, or it can be the cause of metabolic alkalosis when retention is excessive.
Because metabolism continually produces acids, maintenance of pH within these incredibly narrow limits depends on two processes: buffering and compensation. Which statement describes a function of buffering? It helps to prevent large changes in pH by absorbing or releasing H+ ions. The lungs, under the control of chemoreceptor areas in the brainstem respiratory center, are responsible for controlling the amount of carbon dioxide in the blood. The renal system excretes acids and bases from the body as needed. The kidneys influence the maintenance of the normal acid-base balance by changing the rate of excretion or retention of H+ and HCO3 ions.
Correct response: It helps to prevent large changes in pH by absorbing or releasing H+ ions. Explanation: Buffers are substances that help to prevent large changes in pH by absorbing or releasing H+ ions. Successful buffering causes extra H+ ions from the weak acids of the buffer pairs to be released into the blood. The function of lungs being responsible for controlling the amount of carbon dioxide in the blood describes respiratory compensation. The function of kidneys influencing the maintenance of the normal acid-base balance describes renal compensation.
Arterial blood gases of a client with a diagnosis of acute renal failure reveal a pH of 7.25, HCO3- level of 21 mEq/L (21 mmol/L), and decreased PCO2 level accompanied by a respiratory rate of 32. This client is most likely experiencing which disorder of acid-base balance? Metabolic acidosis Metabolic alkalosis Respiratory acidosis Respiratory alkalosis
Correct response: Metabolic acidosis Explanation: Metabolic acidosis involves a decreased serum HCO3- concentration along with a decrease in pH. In metabolic acidosis, the body compensates for the decrease in pH by increasing the respiratory rate in an effort to decrease PCO2 and H2CO3 levels.
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 Respiratory acidosis Metabolic alkalosis Respiratory alkalosis
Correct response: 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 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 acidosis Respiratory acidosis Metabolic alkalosis Respiratory alkalosis
Correct response: 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.
A client tells the nurse that the client has been taking Alka-Seltzer (bicarbonate—antacid) four times a day for the past 2 weeks for an upset stomach. Upon assessment of the client, the nurse notes hyperactive reflexes, tetany, and mental confusion. Arterial blood gases reveal pH 7.55; serum HCO3− 37 mEq/L (37 mmol/L). The nurse suspects the client may be experiencing: Metabolic alkalosis Respiratory acidosis Metabolic acidosis Respiratory alkalosis
Correct response: Metabolic alkalosis Explanation: Metabolic alkalosis is characterized by a serum pH greater than 7.45; serum HCO3− greater than 29 mEq/L (29 mmol/L); and a base excess greater than 3.0. Transient or acute alkalosis is common during or immediately following excess oral ingestion of bicarbonate antacids. Respiratory acidosis as well as metabolic acidosis would have a decrease in pH. Respiratory alkalosis would have an increase in pH and a HCO3− less than 24 mEq/L (24 mmol/L).
The renal control mechanism of restoring the acid-base balance is accomplished through which process? Reabsorption of HCO3 and excretion of H+ restores acid-base balance through the renal control mechanisms. Regulation of the production of carbonic acid Reabsorption of hydrogen and excretion of carbonic acid Stimulation of the chemoreceptors in the brain stem
Correct response: Reabsorption of HCO3 and excretion of H+ restores acid-base balance through the renal control mechanisms. Explanation: Reabsorption of HCO3 and excretion of H+ restores acid-base balance through the renal control mechanisms. Respiratory control mechanisms of restoring acid-base balance are done via regulation of production of carbonic acid and stimulation of the chemoreceptors in the brain.
The nurse is caring for a client who complains of headache and blurred vision. The nurse recognizes that these symptoms, accompanied by increased plasma partial pressure carbon dioxide (PCO2) level and decreased pH level, are consistent with which diagnosis? Respiratory acidosis Respiratory alkalosis Metabolic alkalosis Metabolic acidosis
Correct response: Respiratory acidosis Explanation: Respiratory acidosis is reflected in the ABG as an increased PCO2 and decreased pH level as well as headache, blurred vision, irritability, muscle twitching, and psychological disturbances.
A 77-year-old client diagnosed with chronic obstructive pulmonary disease (COPD) is experiencing impaired gas exchange and CO2 retention, despite a rapid respiratory rate. Which pathophysiologic principle would the health care team expect if the client's compensatory mechanisms are working? Arterial blood gas sampling indicates a pH in the range of 7.45-7.55. The kidneys are likely to reabsorb H+ and secrete HCO3-. The body will produce excess metabolic CO2. The kidneys will adapt with an increase in plasma HCO3- and the pH will increase.
Correct response: The kidneys will adapt with an increase in plasma HCO3- and the pH will increase. Explanation: Respiratory acidosis is accompanied by renal adaptation with a more marked increase in plasma HCO3- and a lesser increase in pH. The client's pH is likely below 7.35, and the likely renal response involves the reabsorption of HCO3- and secretion of H+. Excess CO2 production is not a common manifestation of obstructive lung disease.
As other mechanisms prepare to respond to a pH imbalance, immediate buffering is a result of increased: intracellular albumin. hydrogen/potassium binding. sodium/phosphate anion absorption. bicarbonate/carbonic acid regulation.
Correct response: bicarbonate/carbonic acid regulation. Explanation: The bicarbonate buffering system, which is the principal ECF buffer, uses H2CO3 as its weak acid and bicarbonate salt such as sodium bicarbonate (NaHCO3) as its weak base. It substitutes the weak H2CO3 for a strong acid such as hydrochloric acid or the weak bicarbonate base for a strong base such as sodium hydroxide. The bicarbonate buffering system is a particularly efficient system because its components can be readily added or removed from the body. Hydrogen and potassium exchange freely across the cell membrane to regulate acid-base balance. Sodium is not part of the buffering system. Intracellular protein is part of the body protein buffer system; albumin is extracellular.
A dialysis unit nurse caring for a client with renal failure will expect the client to exhibit which fluid and electrolyte imbalances? fluid volume excess and acidosis fluid volume deficit and alkalosis fluid volume excess and alkalosis fluid volume deficit and acidosis
Correct response: fluid volume excess and acidosis Explanation: Fluid volume excess can be caused by malfunction of the kidneys (i.e., renal failure). The kidneys are also responsible for acid-base balance, and in the presence of renal failure, the kidneys cannot regulate hydrogen ions and bicarbonate ions, so the client develops metabolic acidosis.
The nurse is caring for a client with metabolic alkalosis. Which of these arterial blood gas results supports this diagnosis? pH of 7.50 and HCO3 of 45 mEq/L (45 mmol/L) pH of 7.25 and HCO3 of 18 mEq/L (18 mmol/L) pH of 7.45 and HCO3 of 24 mEq/L (24 mmol/L) pH of 7.35 and HCO3 of 22 mEq/L (22 mmol/L)
Correct response: pH of 7.50 and HCO3 of 45 mEq/L (45 mmol/L) Explanation: A diagnosis of metabolic acidosis is made on the basis of decreased pH and HCO3 levels. A pH of 7.25 is well below the reference range of 7.35 - 7.45 and an HCO3 level of 18 mEq/L is below the reference range of 22 - 26 mEq/L. A ph level that is above the reference range suggests alkalosis, not acidosis. Similarly, an HCO3 level about the reference range is associated with alkalosis.
