Acid Base / Acid-Base Balance
The nurse reviews blood gas results for several children with respiratory disorders. Based on the following results, which intervention by the nurse is most appropriate for each child? Use all options. Child 1: pH 7.261 PaCO2 56 HCO3 24 Child 2: pH 7.53 PaCO2 42 HCO3 51 Child 3: pH 7.41 PaCO2 39 HCO3 24 Child 4: pH 7.49 PaCO2 33 HCO3 24 Child 5: pH 7.28 PaCO2 38 HCO3 18 Administer potassium chloride. Administer oxygen. Continue current treatment. Infuse sodium bicarbonate. Apply a rebreather mask.
1. Administer oxygen. 2. Administer potassium chloride. 3. Continue current treatment. 4. Apply a rebreather mask. 5. Infuse sodium bicarbonate. The first step in analyzing ABGs is to look at the pH. Normal blood pH is 7.4, plus or minus 0.05, forming the range 7.35 to 7.45. If blood pH falls below 7.35, it is acidic. If blood pH is above 7.45, it is alkalotic. If it falls into the normal range, label which side of 7.4 it falls on. Lower than 7.4 is normal/acidic, higher than 7.4 is normal/alkalotic. Label it. The second step is to examine the pCO2. Normal pCO2 levels are 35-45mmHg. Below 35 is alkalotic, above 45 is acidic. Label it. The third step is to look at the HCO3 level. A normal HCO3 level is 22-26 mEq/L. If the HCO3 is below 22, the patient is acidotic. If the HCO3 is above 26, the patient is alkalotic. Label it. Next, match either the pCO2 or the HCO3 with the pH to determine the acid-base disorder. For example, if the pH is acidotic, and the CO2 is acidotic, then the acid-base disturbance is being caused by the respiratory system. Therefore, we call it a respiratory acidosis. However, if the pH is alkalotic and the HCO3 is alkalotic, the acid-base disturbance is being caused by the metabolic (or renal) system. Therefore, it will be a metabolic alkalosis. Analysis of the ABGs finds the following: Child 1 is in respiratory acidosis, which requires the administration of oxygen. Child 2 is in metabolic alkalosis. This condition is often caused by excessive vomiting, resulting in a loss of chloride ions. It is often corrected with the administration of potassium chloride. Child 3 has normal blood gas values and the current treatment should be continued. Child 4 has respiratory alkalosis for which a rebreather mask should be used. Child 5 has metabolic acidosis, which is treated with IV infusion of sodium bicarbonate.
A client is admitted with a diagnosis of diabetic ketoacidosis. An insulin drip is initiated with 50 units of insulin in 100 ml of normal saline solution. The I.V. is being infused via an infusion pump and the pump is currently set at 10 ml/hour. The nurse determines that the client is receiving how many units of insulin each hour? Record your answer using a whole number.
5 Units To determine the number of insulin units the client is receiving per hour, the nurse must first determine the number of units in each ml of fluid (50 units ÷ 100 ml = 0.5 units/ml). Next, she multiplies the units/ml by the rate of ml/hour (0.5 units × 10 ml/hr = 5 units).
A client receiving chemotherapy for metastatic colon cancer is admitted to the oncology unit due to several days of vomiting. Assessment findings include: irregular pulse of 120, blood pressure 88/48, respiratory rate of 14, serum potassium of 2.9 mEq/L (2.9 mmol/l), and arterial blood gas—pH 7.46, PCO2 45 (6 kPa), PO2 95 (12.6 kPa), bicarbonate level 29 mEq/L (29 mmol/l). Which of the following interventions is appropriate for the nurse to administer to the client? a) 5% Dextrose in 0.45% Normal Saline with KCl 40 at 125 mL/hour. b) Oxygen at 4L per nasal cannula. c) 12-lead EKG. d) Repeat laboratory work in 4 hours.
a) 5% Dextrose in 0.45% Normal Saline with KCl 40 at 125 mL/hour. The vital signs suggest that the client is dehydrated from the vomiting, and the nurse should first infuse the IV fluids with the addition of potassium. There is no indication that the client needs oxygen at this time since the PO2 is 95 (12.6 kPa). Although the client has a rapid and irregular pulse, the infusion of fluids may cause the heart rate to return to normal, and the 12-lead EKG can be prescribed after starting the intravenous fluids.
The nurse is caring for a lethargic 4-year-old who is a victim of a near-drowning accident. The nurse should first: a) Administer oxygen. b) Institute rewarming. c) Prepare for intubation. d) Start an intravenous infusion.
a) Administer oxygen. Near-drowning victims typically suffer hypoxia and mixed acidosis. The priority is to restore oxygenation and prevent further hypoxia. Here, the client has blunted sensorium, but is not unconscious; therefore, delivery of supplemental oxygen with a mask is appropriate. Warming protocols and fluid resuscitation will most likely be needed to help correct acidosis, but these interventions are secondary to oxygen administration. Intubation is required if the child is comatose, shows signs of airway compromise, or does not respond adequately to more conservative therapies.
A client is in a metabolic acidosis from severe diarrhea. What assessment finding would be most concerning? a) Irregular heart rate b) Abdominal cramping c) Respiratory rate of 28 d) Excoriated skin around the rectum
a) Irregular heart rate Diarrhea causes a bicarbonate deficit. With loss of the relative alkalinity of the lower GI tract, the relative acidity of the upper GI tract predominates, leading to metabolic acidosis. The diarrhea would result in skin breakdown. Abdominal cramping would be anticipated. Kussmaul respirations are anticipated as a compensatory response. Irregular heart rate could be a sign of electrolyte imbalances and is most concerning
The nurse should assess the client with severe diarrhea for which acid-base imbalance? a) Metabolic acidosis. b) Metabolic alkalosis. c) Respiratory alkalosis. d) Respiratory acidosis.
a) Metabolic acidosis. A client with severe diarrhea loses large amounts of bicarbonate, resulting in metabolic acidosis. Metabolic alkalosis does not result in this situation. Diarrhea does not affect the respiratory system.
A client presents to the emergency department, reporting that he has been vomiting every 30 to 40 minutes for the past 8 hours. Frequent vomiting puts this client at risk for which imbalances? a) Metabolic alkalosis and hypokalemia b) Metabolic acidosis and hyperkalemia c) Metabolic alkalosis and hyperkalemia d) Metabolic acidosis and hypokalemia
a) Metabolic alkalosis and hypokalemia Gastric acid contains large amounts of potassium, chloride, and hydrogen ions. Excessive vomiting causes loss of these substances, which can lead to metabolic alkalosis and hypokalemia. Excessive vomiting doesn't cause metabolic acidosis or hyperkalemia.
A client has the following arterial blood gas values: pH, 7.52; PaO2, 50 mm Hg (6.7 kPa); PaCO2, 28 mm Hg (3.72 kPa); HCO3-, 24 mEq/L (24 mmol/l). Based upon the client's PaO2, which of the following conclusions would be accurate? a) The client is severely hypoxic. b) The oxygen level is low but poses no risk for the client. c) The client requires oxygen therapy with very low oxygen concentrations. d) The client's PaO2 level is within normal range.
a) The client is severely hypoxic. Normal PaO2 level ranges from 80 to 100 mm Hg (10.6 to 13.3 kPa). When the PaO2 value falls to 50 mm Hg (6.7 kPa), the nurse should be alert for signs of hypoxia and impending respiratory failure. An oxygen level this low poses a severe risk for respiratory failure. The PaO2 is not within normal range. The client will require oxygenation at a concentration that maintains the PaO2 at 55 to 60 mm Hg or more (7.3 to 8 kPa).
When caring for a 12-month-old infant with dehydration and metabolic acidosis, the nurse expects to see: a) tachypnea. b) shallow respirations. c) a reduced white blood cell (WBC) count. d) a decreased platelet count.
a) tachypnea. The nurse would expect to see tachypnea because the body compensates for metabolic acidosis via the respiratory system, which tries to eliminate the buffered acids by increasing alveolar ventilation through deep, rapid respirations. Altered WBC and platelet counts aren't specific signs of metabolic imbalance.
Before seeing a newly assigned client with respiratory alkalosis, a nurse quickly reviews the client's medical history. Which condition is a predisposing factor for respiratory alkalosis? a) Myasthenia gravis b) Extreme anxiety c) Type 1 diabetes mellitus d) Opioid overdose
b) Extreme anxiety Extreme anxiety may lead to respiratory alkalosis by causing hyperventilation, which results in excessive carbon dioxide (CO2) loss. Other conditions that may set the stage for respiratory alkalosis include fever, heart failure, injury to the brain's respiratory center, overventilation with a mechanical ventilator, pulmonary embolism, and early salicylate intoxication. Type 1 diabetes may lead to diabetic ketoacidosis; the deep, rapid respirations occurring in this disorder (Kussmaul's respirations) don't cause excessive CO2 loss. Myasthenia gravis and opioid overdose suppress the respiratory drive, causing CO2 retention, not CO2 loss; this may lead to respiratory acidosis, not alkalosis.
The nurse interprets which of the following as an early sign of acute respiratory distress syndrome (ARDS) in a client at risk? a) Elevated carbon dioxide level. b) Hypoxia not responsive to oxygen therapy. c) Severe, unexplained electrolyte imbalance. d) Metabolic acidosis.
b) Hypoxia not responsive to oxygen therapy. A hallmark of early ARDS is refractory hypoxemia. The client's PaO2 level continues to fall, despite higher concentrations of administered oxygen. Elevated carbon dioxide and metabolic acidosis occur late in the disorder. Severe electrolyte imbalances are not indicators of ARDS.
The nurse is admitting a toddler with the diagnosis of near-drowning in a neighbor's heated swimming pool to the Emergency Department. The nurse should assess the child for: a) Fluid aspiration. b) Hypoxia. c) Hypothermia. d) Cutaneous capillary paralysis.
b) Hypoxia. Hypoxia is the primary problem because it results in brain cell damage. Irreversible brain damage occurs after 4 to 6 minutes of submersion. Hypothermia occurs rapidly in infants and children because of their large body surface area. Hypothermia is more of a problem when the child is in cold water. Although fluid aspiration occurs in most drownings and results in atelectasis and pulmonary edema, further aggravating hypoxia, hypoxia is the primary problem. Cutaneous capillary paralysis is not a problem.
Which of the following respiratory patterns indicates increasing intracranial pressure in the brain stem? a) Rapid, shallow respirations. b) Slow, irregular respirations. c) Asymmetric chest excursion. d) Nasal flaring.
b) Slow, irregular respirations. Neural control of respiration takes place in the brain stem. Deterioration and pressure produce irregular respiratory patterns. Rapid, shallow respirations, asymmetric chest movements, and nasal flaring are more characteristic of respiratory distress or hypoxia.
For the child diagnosed with an asthma attack, which of the following manifestations would best correlate with the child's arterial blood gas results, which include pH of 7.46, bicarbonate of 21 mEq/L (21 mmol/L), and a partial pressure of carbon dioxide (PCO2) of 33 mm Hg (4.4 kPa)? a) Heart rate of 68 beats/minute. b) Tingling sensation in the fingertips. c) Greatly diminished breath sounds. d) Absence of urination for several hours.
b) Tingling sensation in the fingertips. The arterial blood gas results indicate respiratory alkalosis. As the alkalinity of body fluids increases, ionization of calcium decreases. A low level of circulating ionized calcium increases the excitability of nerve and muscle tissue, manifested by paresthesia (numbness and tingling) of the digits, upper lip, and earlobes. In mild asthma with respiratory alkalosis, breath sounds are typically loud with expiratory wheezing. In mild asthma with respiratory alkalosis, the heart rate is usually elevated because of hyperventilation. In mild asthma with respiratory alkalosis, urine production is increased because of the increased renal circulation. As a result, bicarbonate, sodium, and potassium excretion increases in an attempt to conserve hydrogen to correct the alkalosis.
Which of the following physical sensations will the client who has had an abdominal hysterectomy most likely experience if she hyperventilates while performing deep-breathing exercises? a) Mental confusion. b) Dyspnea. c) Dizziness. d) Blurred vision.
c) Dizziness. Hyperventilation occurs when the client breathes so rapidly and deeply that she exhales excessive amounts of carbon dioxide. A characteristic symptom of hyperventilation is dizziness. To avoid hyperventilation, the nurse should assist the client in the practice of slow, deep breathing in a regular breathing pattern. Dyspnea, blurred vision, and mental confusion are not associated with hyperventilation.
Which of the following findings would be expected in a client with chest trauma, rib fractures, and respiratory acidosis?" a) Kussmaul respirations due to inability to take deep breaths b) Hyperventilation due to inability to take deep breaths, so short fast breaths are more comfortable c) Hypoventilation due to inability to take deep breaths because of pain d) A massive diffusion disturbance due to the rib fractures
c) Hypoventilation due to inability to take deep breaths because of pain Hypoventilation causes a buildup of CO2 in the blood. Kussmaul respirations are related to abnormal respiratory patterns and are characterized by rapid, deep breathing. They are often seen in clients with metabolic acidosis, and hyperventilation would not cause acidosis. The choice rib fractures do not represent any information in the scenario.
Oxygen at the rate of 2 liters per minute through nasal cannula is prescribed for a client with chronic obstructive pulmonary disease (COPD). Which of the following statements best describes why the oxygen therapy is maintained at a relatively low concentration? a) The cells in the alveoli are so damaged by the client's long history of respiratory problems that increased oxygen levels and reduced carbon dioxide levels likely will cause the cells to burst. b) The oxygen will be lost at the client's nostrils if given at a higher level with a nasal cannula. c) The client's respiratory center is so used to high carbon dioxide and low oxygen levels that changing these levels may eliminate his stimulus for breathing. d) The client's long history of respiratory problems indicates that he would be unable to absorb oxygen given at a higher rate.
c) The client's respiratory center is so used to high carbon dioxide and low oxygen levels that changing these levels may eliminate his stimulus for breathing. Relatively low concentrations of oxygen are administered to clients with COPD so as not to eliminate their respiratory drive. Carbon dioxide content in the blood normally regulates respirations. Clients with COPD, though, are often accustomed to high carbon dioxide levels; the low oxygen blood level is their stimulus to breathe. If they receive excessive oxygen and experience a drop in the blood carbon dioxide level, they may stop breathing. Oxygen flow rate is not diminished at high levels when administered through a nasal cannula. The client's ability to absorb oxygen administered at a higher level is not affected. Increased oxygen levels and decreased carbon dioxide levels cannot cause cells to burst.
On admission, a client has the following arterial blood gas (ABG) values: PaO2, 50 mm Hg; PaCO2, 70 mm Hg; pH, 7.20; HCO3-, 28 mEq/L. Based on these values, the nurse should prioritize which nursing diagnosis for this client? a) Ineffective airway clearance b) Deficient fluid volume c) Metabolic acidosis d) Impaired gas exchange
d) Impaired gas exchange The client's below-normal value for the partial pressure of arterial oxygen (PaO2) and an above-normal value for the partial pressure of arterial carbon dioxide (PaCO2) support the nursing diagnosis of Impaired gas exchange. ABG values can't indicate a diagnosis of Ineffective airway clearance (or excess) or Risk for deficient fluid volume. Metabolic acidosis is a medical, not nursing, diagnosis; in any event, these ABG values indicate respiratory, not metabolic, acidosis.
An adolescent is admitted for treatment of bulimia nervosa. When developing the care plan, the nurse anticipates including interventions that address which metabolic disorder? a) Hypoglycemia b) Metabolic acidosis c) Hyperkalemia d) Metabolic alkalosis
d) Metabolic alkalosis In a client with bulimia nervosa, metabolic alkalosis may occur secondary to hydrogen loss caused by frequent, self-induced vomiting. Typically, the blood glucose level is within normal limits, making hypoglycemia unlikely. In bulimia nervosa, hypokalemia is more common than hyperkalemia and typically results from potassium loss related to frequent vomiting.
A client's arterial blood gas analysis reveals an excess of carbon dioxide. The nurse should recognize that this is consistent with which of the following? a) Metabolic acidosis b) Respiratory alkalosis c) Metabolic alkalosis d) Respiratory acidosis
d) Respiratory acidosis An increased level of dissolved carbon dioxide (PaCO2) indicates respiratory acidosis. Metabolic acidosis and alkalosis are not correct because this is a respiratory issue, not a metabolic one. Respiratory alkalosis would have a PaCO2 deficit, not an increase.
