Chapter 18
A patient has the following arterial blood gas (ABG) values: pH, 7.20; PaO2, 106 mm Hg; pCO2, 35 mm Hg; and , 11 mEq/L. What symptom would be most consistent with the ABG values? a. Diarrhea b. Shortness of breath c. Central cyanosis d. Peripheral cyanosis
ANS: A Diarrhea is one mechanism by which the body can lose large amounts of . The other choices are indications of hypoxia, which is not indicated with a PaO2 of 106 mm Hg.
What chest radiography finding is consistent with a left pneumothorax? a. Flattening of the diaphragm b. Shifting of the mediastinum to the right c. Presence of a gastric air bubble d. Increased radiolucency of the left lung field
ANS: B Shifting of the mediastinal structures away from the area of involvement is a sign of a pneumothorax.
Determination of oxygenation status by oxygen saturation alone is inadequate. What other value must be known? a. pH b. PaCO2 c. HCO- 3 d. Hemoglobin (Hgb)
ANS: D Proper evaluation of the oxygen saturation level is vital. For example, an SaO2 of 97% means that 97% of the available hemoglobin is bound with oxygen. The word available is essential to evaluating the SaO2 level because the hemoglobin level is not always within normal limits and oxygen can bind only with what is available.
Severe coughing and shortness of breath during a thoracentesis are indicative of what complication? a. Re-expansion pulmonary edema b. Pleural infection c. Pneumothorax d. Hemothorax
ANS: A Re-expansion pulmonary edema can occur when a large amount of effusion fluid (~1000 to 1500 mL) is removed from the pleural space. Removal of the fluid increases the negative intrapleural pressure, which can lead to edema when the lung does not re-expand to fill the space. The patient experiences severe coughing and shortness of breath. The onset of these symptoms is an indication to discontinue the thoracentesis.
A static lung compliance of 40 mL/cm H2O is indicative of which disorder? a. Pneumonia b. Bronchospasm c. Pulmonary emboli d. Upper airway obstruction
ANS: A Static compliance is measured under no-flow conditions so that resistance forces are removed. Static compliance decreases with any decrease in lung compliance, such as occurs with pneumothorax, atelectasis, pneumonia, pulmonary edema, and chest wall restrictions. A normal value is 57 to 85 mL/cm of H2O.
A patient is admitted with acute lung failure secondary to pneumonia. Arterial blood gas (ABG) values on the current ventilator settings are pH, 7.37; PaCO2, 50 mm Hg; and HCO3 ̄, 27 mEq/L. What is the correct interpretation of the patient's ABG values? a. Compensated respiratory acidosis b. Compensated metabolic alkalosis c. Uncompensated respiratory alkalosis d. Uncompensated metabolic acidosis
ANS: A The ABG values reflect a compensated respiratory acidosis. Values include a pH of 7.35 to 7.39, PaCO2 above 45 mm Hg, and above 26 mEq/L. Uncompensated respiratory alkalosis values include a pH below 7.35, PaCO2 above 45 mm Hg, and of 22 to 26 mEq/L. Compensated metabolic alkalosis values include a pH of 7.41 to 7.45, PaCO2 above 45 mm Hg, and above 26 mEq/L. Uncompensated metabolic acidosis values include a pH above 7.35, PaCO2 of 35 to 45 mm Hg, and below 22 mEq/L.
On admission, a patient presents with a respiratory rate of 28 breaths/min, heart rate of 108 beats/min in sinus tachycardia, and a blood pressure of 140/72 mm Hg. The patient's arterial blood gas (ABG) values on room air are PaO2, 60 mm Hg; pH, 7.32; PaCO2, 45 mm Hg; and , 26 mEq/L. What action should the nurse anticipate for this patient? a. Initiate oxygen therapy. b. Prepare for emergency intubation. c. Administer 1 ampule of sodium bicarbonate. d. Initiate capnography.
ANS: A The patient is hypoxemic and oxygen therapy should be initiated at this time. The patient's arterial blood gas (ABG) values do not warrant intubation at this time. Sodium bicarbonate is not indicated because this patient has a normal bicarbonate level. Capnography would not be indicated at this time as the patient's CO2 is normal. A repeat ABG may be ordered to assess the patient's ongoing respiratory status.
Ventilation-perfusion (V/Q) scans are ordered to evaluate the possibility of which of the following? a. Pulmonary emboli b. Acute myocardial infarction c. Emphysema d. Acute respiratory distress syndrome
ANS: A This test is ordered for the evaluation of pulmonary emboli. Electrocardiography or cardiac enzymes are ordered to evaluate for myocardial infarction; arterial blood gas analysis, chest radiography, and pulmonary function tests are ordered to evaluate for emphysema. Chest radiography and hemodynamic monitoring are ordered for evaluation of acute respiratory distress syndrome.
A patient presents with absent lung sounds in the left lower lung fields, moderate shortness of breath, and dyspnea. The nurse suspects pneumothorax and notifies the practitioner. Orders for a STAT chest radiography and reading are obtained. Which finding best supports the nurse's suspicions? a. Blackness in the left lower lung area b. Whiteness in the left lower lung area c. Blunted costophrenic angles d. Elevated left hemidiaphragm
ANS: A With a pneumothorax, the pleural edges become evident as one looks through and between the images of the ribs on the film. A thin line appears just parallel to the chest wall, indicating where the lung markings have pulled away from the chest wall. In addition, the collapsed lung will be manifested as an area of increased density separated by an area of radiolucency (blackness).
Place the steps for analyzing arterial blood gases in the proper order. 1. Assess level for metabolic abnormalities 2. Assess PaO2 for hypoxemia 3. Examine PaCO2 for acidosis or alkalosis 4. Re-examine pH to determine level of compensation 5. Examine pH for acidemia or alkalemia a. 5, 1, 2, 4, 3 b. 2, 5, 3, 1, 4 c. 1, 2, 4, 3, 5 d. 1, 3, 4, 5, 2
ANS: B A methodic approach when assessing arterial blood gases allows the nurse to detect subtle changes. A methodic approach includes look at the PaO2 level, look at the pH level, look at the PaCO2 level, look at the , and look again at the pH level.
A patient with chronic obstructive pulmonary disease (COPD) requires intubation. After the practitioner intubates the patient, the nurse auscultates for breath sounds. Breath sounds are questionable in this patient. Which action would best assist in determining endotracheal tube placement in this patient? a. Stat chest radiographic examination b. End-tidal CO2 monitor c. Ventilation-perfusion (V/Q) scan d. Pulmonary artery catheter insertion
ANS: B Although a stat chest radiography examination would be helpful, it has a long turnaround time, and the patient's respiratory status can deteriorate quickly. An end-tidal CO2 monitor gives an immediate response, and the tube can then be reinserted without delay if incorrectly placed. The other tests are not for endotracheal tube placement.
A bronchoscopy is indicated for a patient with what condition? a. Pulmonary edema b. Ineffective clearance of secretions c. Upper gastrointestinal bleed d. Instillation of surfactant
ANS: B Bronchoscopy visualizes the bronchial tree. If secretions are present, they can be removed by suctioning and sent for culture to help adjust antibiotic therapy.
Which patient would be considered hypoxemic? a. A 70-year-old man with a PaO2 of 72 b. A 50-year-old woman with a PaO2 of 65 c. An 84-year-old man with a PaO2 of 96 d. A 68-year-old woman with a PaO2 of 80
ANS: B Normal PaO2 is 80 to 100 mm Hg in persons younger than 60 years. The formula for determining PaO2 for a person older than 60 years of age is 80 mm Hg minus 1 mm Hg for every year of age above 60 years of age, for example, 70 years old = 80 mm Hg - 10 mm Hg = 70 mm Hg; 84 years old = 80 mm Hg - 20 mm Hg = 60 mm Hg; and 68 years old = 80 mm Hg - 8 mm Hg = 72 mm Hg.
A patient's pulse oximeter alarm goes off. The monitor reads 82%. What is the first action the nurse should perform? a. Prepare to intubate. b. Assess the patient's condition. c. Turn off the alarm and reapply the oximeter sensor. d. Increase O2 level to 4L/NC.
ANS: B The first nursing action would be to assess the patient to see if there is a change in his or her condition. If the patient is stable, then the nurse would turn off the alarm and reapply the oximeter sensor. The pulse oximeter cannot differentiate between normal and abnormal hemoglobin. Elevated levels of abnormal hemoglobin falsely elevate the SpO2. The ability of a pulse oximeter to detect hypoventilation is accurate only when the patient is breathing room air. Because most critically ill patients require some form of oxygen therapy, pulse oximetry is not a reliable method of detecting hypercapnia and should not be used for this purpose.
A patient presents with the following arterial blood gas (ABG) values: pH, 7.20; PaO2, 106 mm Hg; PaCO2, 35 mm Hg; and , 11 mEq/L. What is the interpretation of the patient's ABG? a. Uncompensated respiratory acidosis b. Uncompensated metabolic acidosis c. Uncompensated metabolic alkalosis d. Uncompensated respiratory alkalosis
ANS: B The pH indicates acidosis, and the is markedly decreased, indicating a metabolic disorder. Uncompensated metabolic acidosis values include a pH below 7.35, PaCO2 of 35 to 45 mm Hg, and below 22 mEq/L. Uncompensated respiratory acidosis values include a pH below 7.35, PaCO2 above 45 mm Hg, and of 22 to 26 mEq/L. Uncompensated respiratory alkalosis values include a pH above 7.45, PaCO2 below 35 mm Hg, and of 22 to 26 mEq/L. Uncompensated metabolic alkalosis values include a pH above 7.45, PaCO2 of 35 to 45 mm Hg, and above 26 mEq/L.
The patient's arterial blood gas (ABG) values on room air are PaO2, 40 mm Hg; pH, 7.10; PaCO2, 44 mm Hg; and , 16 mEq/L. What is the interpretation of the patient's ABG? a. Uncompensated respiratory acidosis b. Uncompensated metabolic acidosis c. Compensated metabolic acidosis d. Compensated respiratory acidosis
ANS: B The pH is below normal range (7.35 to7.45), so this is uncompensated acidosis. The PaCO2 normal and the is markedly low. This indicates uncompensated metabolic acidosis. Uncompensated metabolic acidosis values include a pH below 7.35, PaCO2 of 35 to 45 mm Hg, and below 22 mEq/L. Uncompensated respiratory acidosis values include a pH below 7.35, PaCO2 above 45 mm Hg, and of 22 to 26 mEq/L. Compensated metabolic acidosis values include a pH of 7.35 to 7.39, PaCO2 below 35 mm Hg, and below 22 mEq/L. Compensated respiratory acidosis values include a pH of 7.35 to 7.35, PaCO2 above 45 mm Hg, and above 26 mEq/L.
The patient's arterial blood gas (ABG) values on room air are PaO2, 70 mm Hg; pH, 7.31; PaCO2, 52 mm Hg; and , 24 mEq/L. What is the interpretation of the patient's ABG? a. Uncompensated metabolic alkalosis b. Uncompensated respiratory acidosis c. Compensated respiratory acidosis d. Compensated respiratory alkalosis
ANS: B The pH is closer to the acidic level, so the primary disorder is acidosis. Uncompensated respiratory acidosis values include a pH below 7.35, PaCO2 above 45 mm Hg, and of 22 to 26 mEq/L. Compensated respiratory acidosis values include a pH of 7.35 to 7.39, PaCO2 greater than 45 mm Hg, and greater than 26 mEq/L. Compensated respiratory alkalosis values include a pH of 7.41 to 7.45, PaCO2 below 35 mm Hg, and below 22 mEq/L. Uncompensated metabolic alkalosis values include a pH above 7.45, PaCO2 of 35 to 45 mm Hg, and above 26 mEq/L.
Which arterial blood gas (ABG) values represent uncompensated metabolic acidosis? a. pH, 7.29; PaCO2, 57 mm Hg; , 22 mEq/L b. pH, 7.36; PaCO2, 33 mm Hg; , 18 mEq/L c. pH, 7.22; PaCO2, 42 mm Hg; , 18 mEq/L d. pH, 7.52; PaCO2, 38 mm Hg; , 29 mEq/L
ANS: C A pH of 7.22 is below normal, reflecting acidosis. The metabolic component ( ) is low, indicating that the acidosis is metabolic in origin. Uncompensated metabolic acidosis values include a pH below 7.35, PaCO2 of 35 to 45 mm Hg, and below 22 mEq/L.
What medication may be included in the preprocedural medications for a diagnostic bronchoscopy? a. Aspirin for anticoagulation b. Vecuronium to inhibit breathing c. Codeine to decrease the cough reflex d. Cimetidine to decrease hydrochloric acid secretion
ANS: C Preprocedural medications for a diagnostic bronchoscopy may include atropine and intramuscular codeine. Whereas atropine lessens the vasovagal response and reduces the secretions, codeine decreases the cough reflex. When a bronchoscopy is performed therapeutically to remove secretions, decreased cough and gag reflexes are present, which may impair secretion clearance.
A patient is intubated, and sputum for culture and sensitivity is ordered. Which of the following is important for obtaining the best specimen? a. After the specimen is in the container, dilute thick secretions with sterile water. b. Apply suction when the catheter is advanced to obtain secretions from within the endotracheal tube. c. Do not apply suction while the catheter is being withdrawn because this can contaminate the sample with sputum left in the endotracheal tube. d. Do not clear the endotracheal tube of all local secretions before obtaining the specimen.
ANS: C To prevent contamination of secretions in the upper portion of the endotracheal tube, do not apply suction while the catheter is being withdrawn. Clear the endotracheal or tracheostomy tube for all local secretions, avoiding deep airway penetration. This will prevent contamination with upper airway flora. Do not dilute thick secretions with sterile water. This will compromise the specimen.
A patient is admitted with signs and symptoms of a pulmonary embolus (PE). What diagnostic test most conclusive to determine this diagnosis? a. ABG b. Bronchoscopy c. Pulmonary function test d. V/Q scan
ANS: D A ventilation-perfusion (V/Q) scan is the most conclusive test for a pulmonary embolus. Arterial blood gas (ABG) analysis tests oxygen levels in the blood, bronchoscopy is to used view the bronchi, and pulmonary function tests are used to measure lung volume.
In a patient who is hemodynamically stable, which procedure can be used to estimate the PaCO2 levels? a. PaO2/FiO2 ratio b. A-a gradient c. Residual volume (RV) d. End-tidal CO2
ANS: D Capnography is the measurement of exhaled carbon dioxide (CO2) gas; it is also known as end-tidal CO2 monitoring. Normally, alveolar and arterial CO2 concentrations are equal in the presence of normal ventilation-perfusion (V/Q) relationships. In a patient who is hemodynamically stable, the end-tidal CO2 (PetCO2) can be used to estimate the PaCO2. Normally, the PaO2/FiO2 ratio is greater than 286; the lower the value, the worse the lung function. The A-a gradient is normally less than 20 mm Hg on room air for patients younger than 61 years. This estimate of intrapulmonary shunting is the least reliable clinically, but it is used often in clinical decision making. Residual volume is the amount of air left in the lung after maximal exhalation. A normal value is 1200 to 1300 mL.
Which blood gas parameter is the acid-base component that reflects kidney function? a. pH b. PaO2 c. PaCO2 d. HCO3 ̄
ANS: D The bicarbonate ( ) is the acid-base component that reflects kidney function. The bicarbonate is reduced or increased in the plasma by renal mechanisms. The normal range is 22 to 26 mEq/L. pH measures the hydrogen ion concentration of plasma. PaO2 measures partial pressure of oxygen dissolved in arterial blood plasma. PaCO2 measures the partial pressure of carbon dioxide dissolved in arterial blood plasma.
On admission, a patient presents with a respiratory rate of 24 breaths/min, pursed-lip breathing, heart rate of 96 beats/min in sinus tachycardia, and a blood pressure of 110/68 mm Hg. The patient's arterial blood gas (ABG) values on room air are PaO2, 70 mm Hg; pH, 7.38; PaCO2, 52 mm Hg; and , 34 mEq/L. What diagnoses would be most consistent with the above arterial blood gas values? a. Acute pulmonary embolism b. Acute myocardial infarction c. Congestive heart failure d. Chronic obstructive pulmonary disease
ANS: D The fact that the level has increased enough to compensate for the increased pCO2 level indicates that this is not an acute condition because the kidneys can take several days to adjust. The other choices would present with a lower level. The values indicate respiratory acidosis, and one of the potential causes is chronic obstructive pulmonary disease. Potential causes for respiratory alkalosis are pulmonary embolism, acute myocardial infarction, and congestive heart failure.
Which ABG values reflect compensation? a. pH, 7.26; PaCO2, 55 mm Hg; , 24 mEq/L b. pH, 7.30; PaCO2, 32 mm Hg; , 18 mEq/L c. pH, 7.48; PaCO2, 30 mm Hg; , 22 mEq/L d. pH, 7.38; PaCO2, 58 mm Hg; , 30 mEq/L
ANS: D The pH is within normal limits, and both the PaCO2 and the values are abnormal. Compensated respiratory acidosis values include a pH of 7.35 to 7.39, PaCO2 above 45 mm Hg, and above 26 mEq/L.
A 75-kg patient is on a ventilator and may be ready for extubation. A respiratory therapist assesses the patient's rapid shallow breathing index (RSBI). Which result best suggests that the patient is ready for a spontaneous breathing trial? a. RSBI = 150 b. RSBI = 125 c. RSBI = 110 d. RSBI = 90
ANS: D The rapid, shallow breathing index (RSBI) can predict weaning success. An RSBI of less than 105 is considered predictive of weaning success. If the patient is receiving sedation, the medication is discontinued at least 1 hour before the RSBI is measured. If the patient meets criteria for weaning readiness and has an RSBI of less than 105, a spontaneous breathing trial can be performed.
A patient presents moderately short of breath and dyspneic. A chest radiographic examination reveals a large right pleural effusion with significant atelectasis. The practitioner would be most likely to prescribe which procedure? a. Thoracentesis b. Bronchoscopy c. Ventilation-perfusion (V/Q) scan d. Repeat chest radiograph
ANS: A Thoracentesis is a procedure that can be performed at the bedside for the removal of fluid or air from the pleural space. It is used most often as a diagnostic measure; it may also be performed therapeutically for the drainage of a pleural effusion or empyema. No evidence is present that would necessitate a V/Q scan. A bronchoscopy cannot assist in fluid removal. A problem with this chest radiograph is not indicated.
What does an intrapulmonary shunting value of 35% indicate? a. Normal gas exchange of venous blood b. An abnormal finding indicative of a shunt-producing disorder c. A serious and potentially life-threatening condition d. Metabolic alkalosis
ANS: C A shunt greater than 10% is considered abnormal and indicative of a shunt-producing disorder. A shunt greater than 30% is a serious and potentially life-threatening condition that requires pulmonary intervention.
