Adult Critical Care Specialist (ACCS) Practice Test

The NBRC Adult Critical Care Specialty (ACCS) exam doesn’t just test what you know — it tests how well you can apply it under pressure. That’s where memorizing facts falls short, and where real practice questions make the difference. The exam evaluates your ability to interpret patient data, analyze ventilator waveforms, troubleshoot life-threatening situations, and make evidence-based clinical decisions in complex critical care environments. This comprehensive ACCS practice exam is built to strengthen those skills through realistic, board-style questions that closely reflect the difficulty and format of the certification exam.

With 630 carefully developed multiple-choice questions and detailed answer explanations, this study resource helps reinforce essential respiratory care concepts while improving clinical reasoning and test-taking confidence. Every explanation is designed to clarify why the correct answer is right and why the remaining options are less appropriate, helping you build lasting knowledge instead of relying on memorization alone.

Why Choose This ACCS Practice Exam?

Master the knowledge and decision-making skills expected on the Adult Critical Care Specialty certification exam with realistic practice questions designed around the current examination blueprint.

• 630 comprehensive practice questions with detailed rationales
• Board-style multiple-choice format similar to the certification exam
• Covers beginner, intermediate, and advanced critical care concepts
• Strengthens clinical judgment and bedside decision-making
• Reinforces ventilator management and respiratory assessment skills
• Helps identify weak knowledge areas before exam day
• Excellent for independent study or structured review sessions
• Suitable for final exam preparation and ongoing competency review

Consistent exposure to challenging clinical scenarios helps improve confidence while reducing surprises during the actual certification examination.

Complete Coverage of the NBRC ACCS Exam Blueprint

This practice exam covers the major content areas tested on the Adult Critical Care Specialty examination to provide balanced and comprehensive preparation.

• Advanced mechanical ventilation
• Acute Respiratory Distress Syndrome (ARDS)
• Ventilator waveform interpretation
• Pressure-controlled and volume-controlled ventilation
• Pressure Support Ventilation (PSV)
• Airway pressure analysis
• Plateau pressure and peak pressure interpretation
• Driving pressure calculations
• Lung compliance assessment
• Airway resistance evaluation
• Auto-PEEP and intrinsic PEEP
• Dynamic hyperinflation
• Oxygenation assessment
• Gas exchange interpretation
• Arterial blood gas analysis
• Ventilator troubleshooting
• Patient-ventilator synchrony
• Mechanical ventilation alarms
• Spontaneous breathing trials
• Ventilator liberation strategies
• Extubation readiness
• Airway management
• Pulmonary embolism recognition
• Pneumothorax identification
• Pulmonary edema
• Pneumonia management
• COPD exacerbations
• Severe asthma
• Bedside respiratory monitoring
• Critical care emergencies
• Hemodynamic effects of mechanical ventilation
• Lung ultrasound interpretation
• Adult intensive care respiratory management

Comprehensive topic coverage allows you to review both common exam subjects and complex scenarios frequently encountered in critical care practice.

Realistic Clinical Case-Based Practice Questions

Success on the ACCS examination depends on applying knowledge to real patient situations rather than recalling isolated facts. This practice exam emphasizes realistic ICU scenarios that require careful assessment, prioritization, and clinical reasoning.

• Adult ICU case studies
• Ventilator management scenarios
• Emergency airway situations
• Critical care decision-making exercises
• Respiratory failure management
• Oxygenation and ventilation problems
• Interpretation of ventilator graphics
• Recognition of changing patient conditions
• Multi-step clinical reasoning questions
• Prioritization and intervention selection

Practicing case-based questions helps develop the analytical skills needed for both the certification exam and daily critical care practice.

Improve Ventilator Management Skills

Mechanical ventilation remains one of the largest and most challenging portions of the ACCS examination. This resource provides extensive practice interpreting ventilator settings, respiratory mechanics, and patient responses.

• Ventilator mode selection
• Tidal volume adjustment
• PEEP optimization
• FiO₂ titration
• Plateau pressure monitoring
• Peak airway pressure interpretation
• Driving pressure assessment
• Compliance monitoring
• Airway resistance troubleshooting
• Ventilator alarm management
• Patient synchrony optimization
• Weaning strategies
• Extubation decision-making

Regular practice builds confidence in recognizing ventilator problems quickly and selecting appropriate interventions.

Strengthen Critical Thinking for the ACCS Exam

Passing the Adult Critical Care Specialty certification requires sound clinical judgment under pressure. These questions are designed to challenge your reasoning rather than simple memorization.

• Analyze patient assessment findings
• Interpret physiologic changes
• Recognize early clinical deterioration
• Select appropriate respiratory interventions
• Evaluate treatment effectiveness
• Identify priority actions during emergencies
• Integrate laboratory and ventilator data
• Apply evidence-based respiratory care principles

Repeated exposure to complex scenarios improves confidence in making safe, effective clinical decisions.

Detailed Answer Explanations That Teach

Each question includes a carefully written explanation designed to reinforce understanding and strengthen long-term retention.

• Clear rationale for every correct answer
• Clinical reasoning behind each decision
• Reinforcement of important respiratory care principles
• Practical bedside application
• Easy-to-follow educational explanations
• Ideal for independent learning and review

Learning from detailed explanations helps close knowledge gaps while improving exam performance.

Who Will Benefit from This Practice Exam?

Whether you are preparing for certification or refreshing advanced respiratory care knowledge, this study resource provides valuable practice across a wide range of critical care topics.

• Respiratory Therapists preparing for the NBRC ACCS Exam
• Experienced RTs seeking specialty certification
• Critical care respiratory professionals
• ICU respiratory clinicians
• Hospital respiratory departments
• Respiratory therapy educators
• Students completing advanced critical care training
• Professionals reviewing adult mechanical ventilation

The broad range of question difficulty makes this resource useful for both first-time candidates and experienced clinicians seeking additional practice.

Study Smarter and Build Exam-Day Confidence

Consistent practice is one of the most effective ways to improve certification exam performance. Working through realistic clinical scenarios strengthens both knowledge retention and decision-making speed while highlighting areas that need additional review.

Whether you are preparing weeks in advance or completing a final review before your exam, this comprehensive NBRC Adult Critical Care Specialty (ACCS) Practice Exam provides the focused practice needed to approach the certification process with greater confidence and stronger clinical reasoning.

ACCS Sample Questions and Answers

1. A 58-year-old man with severe community-acquired pneumonia is mechanically ventilated. Current settings are volume-controlled ventilation, tidal volume 420 mL (6 mL/kg predicted body weight), respiratory rate 24/min, FiO₂ 0.70, and PEEP 12 cm H₂O. His SpO₂ remains 86%. Plateau pressure is 27 cm H₂O, and chest imaging shows diffuse bilateral infiltrates consistent with moderate ARDS. Hemodynamics are stable.

What is the most appropriate next intervention?

A. Increase tidal volume to 8 mL/kg predicted body weight
B. Increase PEEP while monitoring oxygenation and lung mechanics
C. Reduce respiratory rate to 12/min
D. Decrease PEEP to reduce the risk of barotrauma

Correct Answer: B

Explanation:
This patient has moderate ARDS with persistent hypoxemia despite lung-protective ventilation. His plateau pressure remains below the recommended upper limit of 30 cm H₂O, allowing cautious increases in PEEP to recruit collapsed alveoli and improve oxygenation. Raising tidal volume would increase the risk of ventilator-induced lung injury and is inconsistent with current ARDS management. Lowering the respiratory rate would reduce minute ventilation without improving oxygenation, while decreasing PEEP could worsen alveolar collapse and shunt. During PEEP titration, clinicians should continuously assess oxygenation, plateau pressure, driving pressure, blood pressure, and overall lung compliance to identify the safest and most effective setting.

2. A 67-year-old postoperative cardiac surgery patient suddenly develops hypotension while receiving mechanical ventilation. Blood pressure is 76/42 mm Hg, heart rate is 128/min, central venous pressure is markedly elevated, and breath sounds are absent over the right lung. Peak inspiratory pressure has increased from 24 to 48 cm H₂O.

What should the respiratory therapist recommend immediately?

A. Increase FiO₂ to 100% and repeat arterial blood gases
B. Perform urgent needle decompression of the right chest
C. Administer an inhaled bronchodilator
D. Reduce ventilator tidal volume by 50%

Correct Answer: B

Explanation:
The sudden combination of hypotension, elevated intrathoracic pressure, absent unilateral breath sounds, elevated central venous pressure, and rapidly increasing airway pressures strongly suggests a tension pneumothorax. This is a life-threatening emergency requiring immediate decompression rather than waiting for imaging or laboratory confirmation. Increasing oxygen alone does not relieve the underlying problem, and bronchodilators would not correct unilateral absent breath sounds with cardiovascular collapse. Although ventilator adjustments may temporarily reduce airway pressures, definitive treatment is emergency needle decompression followed by chest tube placement. Rapid recognition of this complication is essential because delayed treatment can quickly lead to cardiac arrest.

3. A patient with severe COPD exacerbation is receiving pressure support ventilation. The therapist notices frequent ineffective inspiratory efforts on the ventilator waveform. Examination reveals significant intrinsic PEEP caused by dynamic hyperinflation.

Which adjustment is most likely to improve patient-ventilator synchrony?

A. Increase external PEEP to partially offset intrinsic PEEP
B. Eliminate all external PEEP
C. Increase tidal volume to 10 mL/kg
D. Increase inspiratory time to 2.5 seconds

Correct Answer: A

Explanation:
Patients with severe airflow obstruction often develop intrinsic PEEP because incomplete exhalation traps air within the lungs. Before initiating inspiration, the patient must overcome this intrinsic pressure, increasing the work of breathing and causing ineffective triggering. Applying an appropriate level of external PEEP, usually below the measured intrinsic PEEP, reduces the pressure difference required to trigger the ventilator and improves synchrony. Removing all PEEP may increase inspiratory effort rather than decrease it. Larger tidal volumes and prolonged inspiratory times generally worsen hyperinflation by reducing expiratory time and increasing air trapping. Continuous waveform assessment helps determine whether synchrony improves after adjustments.

4. A 42-year-old patient with septic shock has the following hemodynamic values after adequate fluid resuscitation:

• Cardiac Index: 4.8 L/min/m²
• Systemic Vascular Resistance: 520 dyn·sec/cm⁵
• Central Venous Pressure: 10 mm Hg
• Mean Arterial Pressure: 58 mm Hg

Which intervention is most appropriate?

A. Administer additional large-volume crystalloid infusion only
B. Initiate a vasopressor such as norepinephrine
C. Begin aggressive diuretic therapy
D. Reduce ventilator PEEP immediately

Correct Answer: B

Explanation:
These hemodynamic findings are characteristic of distributive septic shock after fluid resuscitation. The elevated cardiac index indicates preserved or increased cardiac output, while the markedly reduced systemic vascular resistance reflects profound vasodilation. Since preload appears adequate and hypotension persists, vasopressor therapy is indicated to restore vascular tone and maintain organ perfusion. Additional large fluid boluses may contribute to edema without correcting the primary problem. Diuretics could worsen tissue perfusion, and reducing PEEP would not address systemic vasodilation. Current critical care practice emphasizes early norepinephrine as the preferred first-line vasopressor once adequate intravascular volume has been achieved.

5. A mechanically ventilated patient with severe asthma suddenly develops rising peak inspiratory pressures. Peak pressure increases from 35 to 58 cm H₂O, while plateau pressure remains unchanged at 22 cm H₂O. Breath sounds reveal diffuse bilateral wheezing.

Which finding best explains this change?

A. Decreased lung compliance from worsening pulmonary edema
B. Increased airway resistance due to bronchospasm
C. Development of bilateral pleural effusions
D. Progressive abdominal compartment syndrome

Correct Answer: B

Explanation:
A large increase in peak inspiratory pressure with an unchanged plateau pressure indicates increased resistance within the conducting airways rather than reduced lung compliance. In severe asthma, bronchospasm narrows the airways, requiring greater pressure to deliver the same inspiratory flow. Plateau pressure reflects alveolar pressure after airflow has ceased, so it remains normal when compliance is unchanged. Conditions such as pulmonary edema, pleural effusions, or abdominal compartment syndrome reduce respiratory system compliance, causing both peak and plateau pressures to rise together. Recognizing the difference between airway resistance and lung compliance abnormalities allows rapid identification of the underlying problem and guides appropriate therapy, including bronchodilators and optimization of expiratory time.

6. A 63-year-old man with severe ARDS has been mechanically ventilated for 24 hours using lung-protective ventilation. Despite FiO₂ of 1.0 and PEEP of 16 cm H₂O, his PaO₂ is 54 mm Hg. Plateau pressure is 29 cm H₂O, and he is receiving deep sedation without neuromuscular blockade. Hemodynamics are stable.

What is the most appropriate next intervention?

A. Increase tidal volume to improve oxygenation
B. Initiate prolonged prone positioning therapy
C. Reduce PEEP to minimize barotrauma risk
D. Extubate and begin high-flow nasal cannula therapy

Correct Answer: B

Explanation:
Prone positioning is strongly recommended for patients with moderate to severe ARDS who remain profoundly hypoxemic despite optimized lung-protective ventilation. Turning the patient prone improves ventilation-perfusion matching, recruits dependent lung regions, reduces dorsal lung compression, and distributes transpulmonary pressure more evenly. These physiologic effects often improve oxygenation while decreasing ventilator-induced lung injury. Increasing tidal volume contradicts lung-protective ventilation principles and raises the risk of volutrauma. Lowering PEEP would likely worsen alveolar collapse, and extubation is inappropriate in a patient with severe refractory hypoxemia. Prone sessions typically last 12 to 16 hours daily and require close coordination among the critical care team.

7. A mechanically ventilated patient develops sudden oxygen desaturation from 97% to 82%. The ventilator high-pressure alarm activates, and the therapist observes diminished breath sounds on the left. The endotracheal tube depth has not changed. A suction catheter cannot be advanced through the tube.

What is the most likely cause?

A. Pulmonary embolism
B. Endotracheal tube obstruction by secretions or mucus plug
C. Acute respiratory distress syndrome progression
D. Inadequate humidification causing low tidal volume

Correct Answer: B

Explanation:
An inability to pass a suction catheter through the endotracheal tube strongly suggests mechanical obstruction of the airway, most commonly from thick secretions, blood, or a mucus plug. This obstruction causes elevated airway pressures, hypoxemia, and reduced or absent breath sounds if airflow is severely limited. Immediate management focuses on restoring airway patency through suctioning or replacing the tube if obstruction cannot be relieved quickly. Pulmonary embolism usually does not prevent catheter passage, while worsening ARDS typically causes gradual deterioration rather than sudden obstruction. Rapid identification of tube occlusion is critical because complete blockage can quickly lead to respiratory arrest.

8. A 54-year-old patient with septic shock is receiving norepinephrine. Lactate levels remain elevated, urine output has decreased, and the mean arterial pressure is 58 mm Hg despite escalating vasopressor doses. Bedside echocardiography demonstrates reduced left ventricular contractility.

Which additional therapy is most appropriate?

A. Increase sedation to reduce oxygen demand
B. Initiate an inotropic agent such as dobutamine
C. Discontinue norepinephrine immediately
D. Decrease FiO₂ to reduce oxygen toxicity

Correct Answer: B

Explanation:
Some patients with septic shock develop myocardial dysfunction characterized by impaired ventricular contractility despite adequate preload and vasopressor therapy. When cardiac output remains inadequate because of poor myocardial performance, an inotropic medication such as dobutamine can improve stroke volume, cardiac output, and tissue perfusion. Elevated lactate and declining urine output indicate ongoing organ hypoperfusion. Increasing sedation will not correct myocardial dysfunction, discontinuing norepinephrine may worsen hypotension, and reducing FiO₂ has no effect on circulatory failure. Management should include continuous reassessment of perfusion markers, echocardiographic findings, and hemodynamic response to therapy.

9. A patient with severe traumatic brain injury is mechanically ventilated. Intracranial pressure has increased from 18 to 30 mm Hg, while cerebral perfusion pressure remains borderline. Oxygenation and ventilation are otherwise adequate.

Which ventilator-related intervention should be avoided unless absolutely necessary?

A. Preventing hypoxemia
B. Maintaining normocapnia
C. Applying excessive PEEP that significantly impairs venous return
D. Monitoring plateau pressure

Correct Answer: C

Explanation:
Patients with elevated intracranial pressure require careful optimization of both cerebral oxygen delivery and venous drainage. Excessively high PEEP can increase intrathoracic pressure, reducing cerebral venous outflow and potentially increasing intracranial pressure, particularly if it significantly lowers cardiac output or venous return. Maintaining adequate oxygenation and normal PaCO₂ remains essential because hypoxemia and hypercapnia can both worsen cerebral injury. Plateau pressure monitoring is a routine safety measure and should continue. While moderate PEEP may be appropriate when clinically indicated, unnecessary elevations should be avoided in patients with intracranial hypertension unless the benefits clearly outweigh the risks.

10. A 70-year-old patient recovering from acute respiratory failure is undergoing a spontaneous breathing trial using pressure support ventilation. After 20 minutes, respiratory rate increases from 18 to 36 breaths/min, tidal volume falls steadily, heart rate rises by 25 beats/min, and the patient becomes diaphoretic.

What is the most appropriate interpretation?

A. The spontaneous breathing trial has been successfully completed.
B. The patient demonstrates intolerance and should return to previous ventilator support.
C. Extubation should proceed because oxygen saturation remains above 92%.
D. Increase pressure support until respiratory rate falls below 10 breaths/min.

Correct Answer: B

Explanation:
Successful liberation from mechanical ventilation requires both adequate gas exchange and the ability to sustain spontaneous breathing without excessive physiologic stress. This patient exhibits classic signs of spontaneous breathing trial failure, including tachypnea, decreasing tidal volume, diaphoresis, tachycardia, and increasing work of breathing. Continuing the trial or proceeding with extubation would significantly increase the likelihood of respiratory failure and reintubation. Returning to a comfortable level of ventilator support allows recovery while clinicians identify reversible causes such as cardiac dysfunction, excessive secretions, respiratory muscle weakness, or inadequate airway protection. A structured reassessment should be performed before another weaning attempt.

11. A 61-year-old patient with acute respiratory distress syndrome (ARDS) is receiving pressure-controlled ventilation. Over the past four hours, exhaled tidal volumes have steadily decreased despite no changes to ventilator settings. Peak inspiratory pressure remains constant, but oxygen saturation has fallen from 95% to 88%. Lung auscultation reveals newly diminished breath sounds at both bases.

What is the most likely explanation?

A. Progressive reduction in lung compliance from worsening alveolar collapse
B. Development of severe bronchospasm
C. Ventilator malfunction causing inaccurate pressure delivery
D. Excessive patient respiratory effort

Correct Answer: A

Explanation:
In pressure-controlled ventilation, inspiratory pressure is fixed, so delivered tidal volume depends largely on lung compliance and airway resistance. A gradual decline in exhaled tidal volume while inspiratory pressure remains unchanged usually indicates worsening compliance. In ARDS, progressive alveolar collapse, pulmonary edema, or consolidation decreases lung compliance, resulting in smaller tidal volumes and worsening oxygenation. Bronchospasm typically produces elevated airway resistance and prolonged exhalation, while ventilator malfunction should be considered only after patient-related causes have been evaluated. The therapist should reassess lung mechanics, obtain chest imaging if indicated, evaluate recruitment strategies, and ensure lung-protective ventilation continues.

12. A 48-year-old patient with status asthmaticus is receiving invasive mechanical ventilation. Capnography demonstrates a prolonged expiratory phase, and the expiratory flow waveform fails to return to baseline before the next breath begins. Blood pressure is gradually decreasing.

Which ventilator adjustment is most appropriate?

A. Increase respiratory rate to eliminate hypercapnia
B. Increase inspiratory time to improve gas distribution
C. Reduce respiratory rate and allow additional expiratory time
D. Increase tidal volume to improve minute ventilation

Correct Answer: C

Explanation:
Failure of the expiratory flow waveform to reach baseline indicates incomplete exhalation and dynamic hyperinflation. This air trapping increases intrinsic PEEP, raises intrathoracic pressure, and may eventually reduce venous return, causing hypotension. The primary management strategy is to increase expiratory time by reducing the respiratory rate, shortening inspiratory time, or both. Accepting a degree of permissive hypercapnia is often appropriate if arterial pH remains acceptable. Increasing respiratory rate or tidal volume would worsen air trapping, while a longer inspiratory time further shortens expiration. Continuous waveform analysis helps determine whether dynamic hyperinflation improves after ventilator adjustments.

13. A mechanically ventilated patient with severe pulmonary hypertension develops refractory hypoxemia despite optimization of FiO₂ and PEEP. The intensivist requests inhaled nitric oxide therapy.

What is the primary therapeutic effect of inhaled nitric oxide?

A. Systemic arterial vasodilation and increased cardiac output
B. Selective pulmonary vasodilation in ventilated lung regions
C. Increased surfactant production throughout the lungs
D. Direct bronchodilation of the central airways

Correct Answer: B

Explanation:
Inhaled nitric oxide acts as a selective pulmonary vasodilator because it reaches only ventilated alveoli. It relaxes adjacent pulmonary vascular smooth muscle, improving blood flow to well-ventilated lung regions and enhancing ventilation-perfusion matching. This selective action can improve oxygenation while reducing pulmonary artery pressures without causing significant systemic hypotension because nitric oxide is rapidly inactivated after entering the bloodstream. It is not a bronchodilator and does not stimulate surfactant production. During therapy, clinicians monitor oxygenation, pulmonary hemodynamics when available, methemoglobin levels, and nitrogen dioxide concentrations to ensure both effectiveness and safety.

14. A 72-year-old patient with acute respiratory failure suddenly becomes agitated while receiving pressure support ventilation. The therapist observes double triggering on multiple consecutive breaths. Waveform analysis shows the patient’s inspiratory effort continues after ventilator cycling has ended.

Which adjustment is most likely to improve synchrony?

A. Shorten inspiratory time or increase cycling sensitivity appropriately
B. Increase alarm limits to prevent nuisance alarms
C. Decrease FiO₂ by 20%
D. Add external PEEP regardless of clinical condition

Correct Answer: A

Explanation:
Double triggering often occurs when the ventilator ends inspiration before the patient’s neural inspiratory effort is complete. The patient immediately initiates another breath, resulting in two consecutive ventilator cycles. Adjusting inspiratory time or cycling criteria allows the ventilator breath to better match the patient’s inspiratory demand, improving comfort and synchrony. Simply increasing alarm limits ignores the underlying problem, while decreasing oxygen concentration or routinely adding PEEP does not address the cause of double triggering. Careful waveform interpretation is essential for identifying patient-ventilator dyssynchrony and selecting the most appropriate ventilator adjustment.

15. A 56-year-old patient is recovering from septic shock and prolonged mechanical ventilation. During the morning assessment, the respiratory therapist notes generalized muscle weakness, difficulty generating an effective cough, and a negative inspiratory force of –18 cm H₂O. The patient remains alert and follows commands.

Which factor is most likely contributing to delayed ventilator liberation?

A. Critical illness-acquired respiratory muscle weakness
B. Excessive pulmonary blood flow
C. Mild respiratory alkalosis
D. Increased hemoglobin concentration

Correct Answer: A

Explanation:
Patients requiring prolonged intensive care frequently develop critical illness-acquired weakness involving both peripheral and respiratory muscles. Contributing factors include systemic inflammation, immobility, sepsis, corticosteroid exposure, neuromuscular blocking agents, and inadequate nutrition. A weak cough and reduced inspiratory muscle strength increase the likelihood of extubation failure because the patient may be unable to maintain ventilation or effectively clear secretions. Successful liberation requires more than acceptable oxygenation; adequate respiratory muscle performance is equally important. Management includes minimizing unnecessary sedation, promoting early mobilization, optimizing nutrition, correcting reversible metabolic abnormalities, and using structured spontaneous breathing trials to reassess readiness for extubation.

16. A 65-year-old patient with severe aspiration pneumonia is receiving volume-controlled ventilation. The therapist notes the following ventilator data:

• Peak inspiratory pressure: 42 cm H₂O
• Plateau pressure: 36 cm H₂O
• Tidal volume: 420 mL
• PEEP: 10 cm H₂O

Compared with the previous assessment, both peak and plateau pressures have increased by 10 cm H₂O. Breath sounds reveal diffuse crackles without wheezing.

What is the most likely cause?

A. Acute bronchospasm causing increased airway resistance
B. Reduced lung compliance from worsening pulmonary edema or consolidation
C. Partial obstruction of the endotracheal tube with secretions
D. Water accumulation in the ventilator circuit

Correct Answer: B

Explanation:
When both peak inspiratory pressure and plateau pressure increase together, the problem typically involves reduced respiratory system compliance rather than increased airway resistance. In this patient, diffuse crackles and worsening aspiration pneumonia suggest progression of pulmonary edema, consolidation, or inflammatory lung injury, all of which make the lungs stiffer and more difficult to inflate. Bronchospasm or tube obstruction would primarily increase peak pressure while leaving plateau pressure relatively unchanged. Water in the ventilator circuit may cause intermittent pressure fluctuations but does not consistently elevate plateau pressure. The therapist should reassess lung mechanics, evaluate chest imaging, optimize PEEP, and continue lung-protective ventilation while monitoring for further deterioration.

17. A 59-year-old patient with acute respiratory failure has a sudden decline in oxygen saturation after being transported for a CT scan. Upon returning to the ICU, the ventilator low exhaled tidal volume alarm activates. The ventilator tubing appears intact, and the cuff pressure is appropriate. The therapist hears gurgling sounds over the patient’s neck during inspiration.

What is the most likely explanation?

A. Severe pulmonary embolism
B. Endotracheal tube displacement above the vocal cords
C. Acute pulmonary edema
D. Sudden onset of bronchospasm

Correct Answer: B

Explanation:
Gurgling over the neck accompanied by low exhaled tidal volume strongly suggests that the endotracheal tube has become displaced, allowing delivered gas to escape through the upper airway instead of entering the lungs. Patient movement during transport is a common cause of tube migration. Immediate confirmation of tube position using direct visualization, capnography, and tube depth assessment is essential. If displacement is confirmed, prompt reintubation or repositioning should be performed to prevent complete airway loss. Pulmonary embolism, pulmonary edema, and bronchospasm may impair oxygenation but do not typically produce audible air leakage around the larynx with reduced exhaled tidal volume.

18. A 46-year-old patient with severe sepsis is receiving mechanical ventilation. Laboratory results reveal an arterial lactate level of 5.8 mmol/L despite improvement in blood pressure following fluid resuscitation and vasopressor therapy. Urine output remains low, and skin examination shows cool extremities.

What is the best interpretation of the persistently elevated lactate level?

A. Adequate tissue perfusion has been restored completely.
B. Ongoing tissue hypoperfusion or impaired lactate clearance should be suspected.
C. The elevated lactate is expected after vasopressor therapy and requires no further evaluation.
D. Mechanical ventilation alone is the most likely cause of the elevated lactate.

Correct Answer: B

Explanation:
Persistent elevation of serum lactate after initial resuscitation suggests that tissue oxygen delivery or utilization remains inadequate, or that lactate clearance is impaired. Although improving blood pressure is encouraging, it does not guarantee restoration of microcirculatory perfusion. Continued oliguria and cool extremities further support ongoing organ hypoperfusion. The critical care team should reassess cardiac output, fluid responsiveness, vasopressor requirements, infection control, and other potential causes of inadequate oxygen delivery. Mechanical ventilation itself does not typically produce marked hyperlactatemia. Serial lactate measurements are valuable because decreasing levels generally indicate improving tissue perfusion and a favorable response to treatment.

19. A patient with severe COPD has completed a successful spontaneous breathing trial. Before extubation, the respiratory therapist performs a cuff leak assessment because prolonged intubation and airway edema are concerns. No audible cuff leak is detected.

What is the most appropriate next step?

A. Proceed with extubation because the spontaneous breathing trial was successful.
B. Recognize the increased risk of post-extubation airway obstruction and notify the critical care team.
C. Increase pressure support for another 24 hours without further evaluation.
D. Remove the endotracheal tube immediately to avoid ventilator-associated pneumonia.

Correct Answer: B

Explanation:
The absence of a cuff leak suggests possible laryngeal or upper airway edema, increasing the risk of post-extubation stridor and respiratory distress. While the cuff leak test is not perfectly predictive, it provides valuable information when combined with the patient’s clinical history and risk factors. A successful spontaneous breathing trial evaluates respiratory endurance but does not assess upper airway patency. The care team should consider additional evaluation and, when appropriate, interventions such as corticosteroid therapy before attempting extubation. Extubation decisions should integrate respiratory mechanics, airway protection, neurological status, secretion management, and airway edema risk rather than relying on a single assessment.

20. A 68-year-old patient receiving pressure support ventilation suddenly becomes tachypneic and anxious. Ventilator waveforms demonstrate repeated missed inspiratory efforts that fail to trigger assisted breaths. End-expiratory hold measurement reveals intrinsic PEEP of 10 cm H₂O, while external PEEP is set at 3 cm H₂O.

Which ventilator adjustment is most likely to improve triggering?

A. Increase external PEEP to an appropriate level below intrinsic PEEP
B. Decrease trigger sensitivity substantially to prevent auto-triggering
C. Increase tidal volume to 10 mL/kg predicted body weight
D. Reduce inspiratory flow to prolong inspiratory time

Correct Answer: A

Explanation:
Patients with significant intrinsic PEEP must generate enough negative pressure to overcome trapped alveolar pressure before the ventilator recognizes an inspiratory effort. This additional workload often results in missed triggers, increased work of breathing, and patient discomfort. Applying external PEEP at an appropriate level—generally below the measured intrinsic PEEP—reduces the pressure threshold required to trigger the ventilator, improving synchrony without substantially worsening hyperinflation. Increasing tidal volume or prolonging inspiratory time may increase air trapping by reducing expiratory time. Careful monitoring of pressure and flow waveforms after adjustment helps confirm improved triggering, reduced ineffective efforts, and better patient-ventilator interaction.