📘 Chapter 9 – Objectives Overview
By the end of this chapter, you should be able to:
- Explain oxygen therapy principles and recognize complications (e.g., O₂-induced hypercapnia in COPD).
- Identify common breath sounds and their clinical significance (wheezing, crackles, stridor, pleural rub).
- Interpret arterial blood gases (ABGs) and distinguish between respiratory vs. metabolic acidosis/alkalosis.
- Differentiate obstructive vs. restrictive lung diseases (asthma, COPD, emphysema vs. ARDS, fibrosis, obesity-hypoventilation).
- Recognize ventilator alarms and patient–ventilator problems (↑ peak pressures = obstruction/secretions; ↓ exhaled volume = leak).
- Understand causes of severe hypoxemia, especially ARDS (refractory to supplemental O₂).
- Choose the correct oxygen delivery device (nasal cannula, simple mask, non-rebreather, Venturi mask).
- Demonstrate safe suctioning & airway management; act immediately if complications (e.g., bradycardia) occur.
- Apply test-taking strategies:
- Always ask: “What would an RT do first?”
- Use the ABCs: Airway → Breathing → Circulation.
🧠 Overview (What this chapter is about)
Chapter 9 focuses on balancing oxygenation, ventilation, and patient safety. You’ll match the right device to the right patient, read ABGs to guide actions, respond to ventilator alarms, and manage hypoxemia (including ARDS). Expect scenario questions that ask: What is your best first action?
📌 Key Points to Remember
- COPD + O₂: Watch for CO₂ retention (oxygen-induced hypercapnia).
- Wheezing = narrowed airways (asthma).
- Respiratory acidosis = low pH + high PaCO₂.
- Obstructive vs. Restrictive → know the examples.
- Vent alarms: Obstruction ↑ peak pressure; leak ↓ exhaled volume.
- ARDS: Severe hypoxemia not fixed by O₂ alone (refractory).
- Venturi mask: most precise FiO₂ delivery.
- Suctioning: stop immediately if bradycardia occurs.
- Strategy: Ask “RT first action?” then apply ABCs.
📎 Key Formulas & Values (Quick Reference)
Normal ABG Values
- pH: 7.35–7.45
- PaCO₂: 35–45 mmHg
- HCO₃⁻: 22–26 mEq/L
- PaO₂: 80–100 mmHg
- SaO₂: 95–100%
Low pH + High PaCO₂ = Respiratory Acidosis · High pH + Low PaCO₂ = Respiratory Alkalosis
Oxygen Delivery Devices (Approx. FiO₂)
- Nasal Cannula: 24–44% (1–6 L/min)
- Simple Mask: 40–60% (6–10 L/min)
- Non-Rebreather: up to ~100% (10–15 L/min)
- Venturi Mask: 24–50% (precise; adapter-dependent)
Formulas
- Minute Ventilation (VE): VE = VT × RR
- Alveolar Ventilation (VA): VA = (VT − Dead Space) × RR
- A–a Gradient: A–a = PAO₂ − PaO₂ (↑ = V/Q mismatch, diffusion issue, or shunt)
Critical Thresholds
- SpO₂ < 90% = Hypoxemia
- PaO₂ < 60 mmHg = Severe hypoxemia
- PaCO₂ > 50 mmHg = Hypoventilation
🚨 Reality Check: Patient Lives Depend on You
Every question is practice for a real decision. Train to make the right first action — because a patient’s life may depend on it.
💡 Why Surprise Questions Matter
- Trains Adaptability → you stop panicking at unfamiliar questions.
- Promotes Reasoning over Memorization → you apply principles, not just recall slides.
- Builds Exam Stamina → if quizzes are “too safe,” real exams will crush you.
- Real-World Prep → patients don’t follow the syllabus.
Chapter 9 — The Respiratory System
Objectives (what to master)
- Development: prenatal → birth → postnatal lung growth (alveolar multiplication).
- Fetal circulation & birth transition: ductus arteriosus/foramen ovale; ↓PVR with first breaths/↑PaO2.
- Thorax & pleura; mediastinum; upper vs lower airway functions.
- Lungs: lobes/segments; acinus & alveoli micro-structure; surfactant (Type II cells).
- Mucociliary escalator (goblet cells & submucosal glands) and airway defense.
- Blood–gas barrier (Type I cells/interstitium/endothelium) and diffusion.
- Pulmonary vs bronchial circulation; lymphatics to prevent edema.
- Respiratory muscles: diaphragm (phrenic C3–C5) & accessory groups.
- Neural control: somatic vs autonomic (vagal M3 → constrict/↑mucus).
Flashcards (tap to reveal)
Primary muscle of quiet inspiration?
Innervation of the diaphragm?
Two fetal shunts that bypass the lungs
Change at birth that most lowers PVR
Start of the respiratory zone
Cell that produces surfactant
Surfactant’s primary effect
Main layers of blood–gas barrier
Nutritive blood supply of airways
Lymphatics’ role in lungs
Upper airway boundaries
Lower airway begins at…
Right vs left main bronchus (aspiration risk?)
Lobe count (R vs L)
Primary expiratory muscles (forced)
Pleural pressure during inspiration becomes…
ANS branch → bronchoconstriction & ↑mucus
Main mucus producers in trachea/bronchi
Most of alveolar surface is covered by…
Airway segment where foreign bodies most often lodge
Clickable Practice Quiz (10 Qs)
Tap/click your answer. You’ll see ✓/✗ and the rationale right away.
📘 Chapter 9 – Flashcards
Click a card to flip and reveal the answer.
📝 Chapter 9 – Respiratory Therapy Practice Quiz
Select the best answer, then click “Show Answer” to check with rationale.
1. A patient with COPD is placed on oxygen at 4 L/min via nasal cannula. Which complication should the therapist monitor closely?
- A. Hypoxemia
- B. Hypercapnia
- C. Pneumothorax
- D. Pulmonary embolism
High O₂ can reduce hypoxic drive and cause CO₂ retention.
2. Which breath sound is most likely in an asthma exacerbation?
- A. Crackles
- B. Stridor
- C. Wheezing
- D. Pleural rub
Wheezing = narrowed airways, classic in asthma.
3. ABG: pH 7.31, PaCO₂ 55, HCO₃⁻ 25. Interpretation?
- A. Metabolic acidosis
- B. Respiratory acidosis
- C. Respiratory alkalosis
- D. Metabolic alkalosis
Low pH + High CO₂ = respiratory acidosis.
4. Which of the following are obstructive lung diseases? (Select all that apply)
- A. Asthma
- B. Emphysema
- C. Chronic bronchitis
- D. Pulmonary fibrosis
- E. Cystic fibrosis
Pulmonary fibrosis = restrictive. Others = obstructive.
5. On mechanical ventilation, peak pressures rise suddenly. What is the most likely cause?
- A. Pneumothorax
- B. Secretions in airway
- C. Circuit leak
- D. Hypovolemia
Obstruction ↑ resistance → high peak pressures.
6. A patient has PaO₂ 50 mmHg while on 100% FiO₂. What condition is suspected?
- A. Asthma
- B. ARDS
- C. COPD
- D. Bronchitis
Refractory hypoxemia is hallmark of ARDS.
7. Which device delivers the most accurate FiO₂?
- A. Nasal cannula
- B. Simple mask
- C. Venturi mask
- D. Non-rebreather
Venturi provides precise FiO₂ delivery.
8. While suctioning, the patient’s HR drops suddenly. What should the therapist do first?
- A. Stop suctioning
- B. Increase suction pressure
- C. Continue until airway clears
- D. Give O₂ at higher flow
Bradycardia = vagal stimulation → stop immediately.
9. Which value best reflects adequate ventilation?
- A. PaO₂
- B. PaCO₂
- C. HCO₃⁻
- D. SaO₂
Ventilation = removal of CO₂.
10. Best position for a patient with unilateral lung disease in distress?
- A. Supine
- B. Prone
- C. “Good lung down” lateral
- D. “Bad lung down” lateral
Gravity improves perfusion to the healthy lung.
📝 Chapter 9 – Practice Quiz (Set 1: Questions 1–5)
Answer each question. Click “Show Answer” to reveal the rationale.
1. A patient with COPD is placed on oxygen at 4 L/min via nasal cannula. Which complication should the therapist monitor closely?
- A. Hypoxemia
- B. Hypercapnia
- C. Pneumothorax
- D. Pulmonary embolism
High O₂ can suppress hypoxic drive → CO₂ retention.
2. Which breath sound is most likely in an asthma exacerbation?
- A. Crackles
- B. Stridor
- C. Wheezing
- D. Pleural rub
Wheezing = narrowed airways, classic in asthma.
3. ABG shows: pH 7.31, PaCO₂ 55, HCO₃⁻ 25. Interpretation?
- A. Metabolic acidosis
- B. Respiratory acidosis
- C. Respiratory alkalosis
- D. Metabolic alkalosis
Low pH + High CO₂ = respiratory acidosis.
4. Which of the following are obstructive lung diseases? (Select all that apply)
- A. Asthma
- B. Emphysema
- C. Chronic bronchitis
- D. Pulmonary fibrosis
- E. Cystic fibrosis
Pulmonary fibrosis = restrictive. Others = obstructive.
5. On mechanical ventilation, peak pressures rise suddenly. What is the most likely cause?
- A. Pneumothorax
- B. Secretions in airway
- C. Circuit leak
- D. Hypovolemia
Airway obstruction increases resistance → high peak pressures.
📝 Chapter 9 – Practice Quiz (Set 2: Questions 6–10)
Answer each question. Click “Show Answer” to reveal the rationale.
6. A patient has PaO₂ 50 mmHg while on 100% FiO₂. What condition is suspected?
- A. Asthma
- B. ARDS
- C. COPD
- D. Bronchitis
Refractory hypoxemia despite high FiO₂ is classic for ARDS.
7. Which device delivers the most accurate FiO₂?
- A. Nasal cannula
- B. Simple mask
- C. Venturi mask
- D. Non-rebreather
Venturi entrainment provides precise, fixed FiO₂.
8. While suctioning, the patient’s heart rate drops suddenly. What should the therapist do first?
- A. Stop suctioning
- B. Increase suction pressure
- C. Continue until the airway clears
- D. Give O₂ at higher flow
Bradycardia indicates vagal stimulation—stop immediately, then oxygenate.
9. Which value best reflects adequacy of ventilation?
- A. PaO₂
- B. PaCO₂
- C. HCO₃⁻
- D. SaO₂
Ventilation refers to CO₂ elimination; PaCO₂ is the key indicator.
10. Best position for a patient in respiratory distress with unilateral lung disease?
- A. Supine
- B. Prone
- C. “Good lung down” lateral
- D. “Bad lung down” lateral
Gravity improves perfusion to the healthy lung, optimizing V/Q.
📝 Chapter 9 – Practice Quiz (Set 3: Questions 11–15)
Answer each question. Click “Show Answer” to reveal the rationale.
11. Which ABG result indicates metabolic alkalosis?
- A. pH 7.50, PaCO₂ 40, HCO₃⁻ 32
- B. pH 7.28, PaCO₂ 55, HCO₃⁻ 24
- C. pH 7.49, PaCO₂ 30, HCO₃⁻ 22
- D. pH 7.36, PaCO₂ 46, HCO₃⁻ 28
High pH + elevated bicarbonate = metabolic alkalosis.
12. Which medication is commonly used as a rescue bronchodilator?
- A. Albuterol
- B. Tiotropium
- C. Salmeterol
- D. Fluticasone
Albuterol is a short-acting beta₂ agonist (SABA) used for quick relief.
13. During CPR, which is the recommended compression-to-breath ratio for adults?
- A. 15:1
- B. 30:2
- C. 10:1
- D. Continuous compressions, no breaths
For adults, the correct ratio is 30 compressions to 2 breaths.
14. Which condition is associated with a “barrel chest”?
- A. Asthma
- B. Emphysema
- C. Pneumonia
- D. Pulmonary edema
Chronic hyperinflation in emphysema leads to a barrel-shaped chest.
15. Which blood gas change is expected in hyperventilation?
- A. Increased PaCO₂
- B. Decreased PaCO₂
- C. Increased HCO₃⁻
- D. Decreased pH
Hyperventilation “blows off” CO₂, leading to respiratory alkalosis.
📝 Chapter 9 – Practice Quiz (Set 4: Questions 16–20)
Answer each question. Click “Show Answer” to reveal the rationale.
16. Which test definitively confirms tuberculosis (TB)?
- A. Chest x-ray
- B. PPD skin test
- C. Sputum culture for acid-fast bacilli
- D. CT scan
XR/PPD can suggest TB, but culture confirms active disease.
17. A patient suddenly has absent breath sounds on the left with tracheal deviation to the right. Most likely diagnosis?
- A. Pneumonia
- B. Pleural effusion
- C. Tension pneumothorax
- D. Severe asthma
Unilateral absent sounds + mediastinal shift = classic for tension PTX.
18. Which of the following are restrictive lung diseases? (Select all that apply)
- A. ARDS
- B. Pulmonary fibrosis
- C. Emphysema
- D. Obesity-hypoventilation
- E. Sarcoidosis
Emphysema is obstructive; the others decrease lung compliance → restrictive.
19. A ventilated patient’s PaCO₂ rises from 40 to 60 mmHg. Best ventilator adjustment?
- A. Increase FiO₂
- B. Increase tidal volume
- C. Decrease PEEP
- D. Decrease rate
Rising CO₂ = inadequate ventilation. ↑VT (or ↑RR) increases minute ventilation.
20. Which intervention is part of a ventilator-associated pneumonia (VAP) prevention bundle?
- A. Prone positioning for all patients
- B. Daily sedation vacation and assessment of readiness to extubate
- C. Routine deep suctioning on a fixed schedule
- D. Avoiding oral care to reduce aspiration
VAP bundle includes HOB elevation, oral care, sedation breaks, and early extubation when possible.
📝 Chapter 9 – Clickable Practice Quiz (20 Questions)
Tap/click your answer. You’ll see ✅/❌ and the rationale right away.
Set 1: Questions 1–5
1. A patient with COPD is placed on oxygen at 4 L/min via nasal cannula. Which complication should the therapist monitor closely?
2. Which breath sound is most likely in an asthma exacerbation?
3. ABG shows: pH 7.31, PaCO₂ 55, HCO₃⁻ 25. Interpretation?
4. Which of the following are obstructive lung diseases? (Select all that apply — choose one at a time to check rationales.)
5. On mechanical ventilation, peak pressures rise suddenly. What is the most likely cause?
Set 2: Questions 6–10
6. A patient has PaO₂ 50 mmHg while on 100% FiO₂. What condition is suspected?
7. Which device delivers the most accurate FiO₂?
8. While suctioning, the patient’s HR drops suddenly. What should the therapist do first?
9. Which value best reflects adequacy of ventilation?
10. Best position for a patient in respiratory distress with unilateral lung disease?
Set 3: Questions 11–15
11. Which ABG result indicates metabolic alkalosis?
12. Which medication is commonly used as a rescue bronchodilator?
13. During CPR, which is the recommended compression-to-breath ratio for adults?
14. Which condition is associated with a “barrel chest”?
15. Which blood gas change is expected in hyperventilation?
Set 4: Questions 16–20
16. Which test definitively confirms tuberculosis (TB)?
17. Absent breath sounds on the left + tracheal shift to the right. Most likely diagnosis?
18. Which of the following are restrictive lung diseases? (Select all that apply — check one at a time.)
19. A ventilated patient’s PaCO₂ rises from 40 to 60 mmHg. Best ventilator adjustment?
20. Which intervention is part of a ventilator-associated pneumonia (VAP) prevention bundle?
📝 Chapter 10 – Clickable Practice Quiz (20 Questions)
Tap/click your answer. You’ll see ✅/❌ and the rationale right away.
Set 1: Questions 1–5
1. A post-op patient is somnolent with shallow respirations (RR 8/min). ABG likely shows:
2. Best first action for suspected mucus plugging in a ventilated patient?
3. Which finding suggests impending upper-airway obstruction?
4. Which clinical scenario is most consistent with pulmonary embolism?
5. In suspected tension pneumothorax on the vent, the priority is to:
Set 2: Questions 6–10
6. Which vent change reduces PaCO₂ most directly (volume control)?
7. Which oxygen device is preferred for COPD patient needing precise 28% FiO₂?
8. Elevated plateau pressure with normal peak pressure suggests:
9. Which infection-control action best prevents VAP?
10. A spontaneously breathing patient shows accessory muscle use and paradoxical abdomen. Priority?
Set 3: Questions 11–15
11. An asthmatic’s peak flow improves from 150 to 350 L/min after treatment. This indicates:
12. Before initiating BiPAP for COPD exacerbation, the therapist should:
13. A cuff leak test before extubation primarily assesses risk of:
14. Which ABG suggests a panic attack with hyperventilation?
15. You hear coarse crackles that clear after coughing. This most likely represents:
Set 4: Questions 16–20
16. During ventilator weaning, which sign suggests readiness to extubate?
17. A pneumonia patient has increased WOB, RR 32, and accessory muscle use. Best initial oxygenation strategy?
18. After intubation, the right chest sounds louder than the left with poor chest rise on left. Most likely cause?
19. Which change will most improve oxygenation (with constant ventilation)?
20. Which is the safest suctioning practice?
📝 Chapter 10 – Clickable Practice Quiz (Set 1: Questions 1–10)
Tap/click your answer. You’ll see ✅/❌ and the rationale right away.
1. A post-op patient is somnolent with shallow respirations (RR 8/min). ABG likely shows:
2. Best first action for suspected mucus plugging in a ventilated patient?
3. Which finding suggests impending upper-airway obstruction?
4. Which clinical scenario is most consistent with pulmonary embolism?
5. In suspected tension pneumothorax on the vent, the priority is to:
6. Which vent change reduces PaCO₂ most directly (volume control)?
7. Which oxygen device is preferred for COPD patient needing precise 28% FiO₂?
8. Elevated plateau pressure with normal peak pressure suggests:
9. Which infection-control action best prevents VAP?
10. A spontaneously breathing patient shows accessory muscle use and paradoxical abdomen. Priority?
📝 Chapter 9 — Clickable Practice Quiz (20 Questions)
Tap an answer to read it; open Show answer to see the correct choice and rationale.
Set 1: Questions 1–5
1. A patient with COPD is placed on oxygen at 4 L/min via nasal cannula. Which complication should the therapist monitor closely?
Show answer
2. Which breath sound is most likely in an asthma exacerbation?
Show answer
3. ABG shows: pH 7.31, PaCO₂ 58, HCO₃⁻ 25. Best interpretation?
Show answer
4. Which of the following are obstructive lung diseases? (Select all that apply – use to study)
Show answer
5. On mechanical ventilation, peak inspiratory pressures suddenly rise. Most likely cause?
Show answer
Set 2: Questions 6–10
6. A patient has PaO₂ 50 mmHg while on 100% FiO₂. What condition is suspected?
Show answer
7. Which device delivers the most precise FiO₂ in a spontaneously breathing patient?
Show answer
8. While suctioning, the patient’s HR drops suddenly. First action?
Show answer
9. Which value best reflects adequacy of ventilation?
Show answer
10. A COPD patient on 28% Venturi mask becomes lethargic; ABG: pH 7.28, PaCO₂ 70, PaO₂ 62. Best immediate action?
Show answer
Set 3: Questions 11–15
11. Best first-line bronchodilator for acute asthma?
Show answer
12. What is the most reliable bedside indicator of proper ET-tube placement after intubation?
Show answer
13. Which therapy best treats atelectasis in a cooperative post-op patient?
Show answer
14. A high-flow nasal cannula (HFNC) primarily improves oxygenation by:
Show answer
15. After starting aerosolized albuterol, which change indicates improvement?
Show answer
Set 4: Questions 16–20
16. Which alarm change suggests a ventilator circuit leak?
Show answer
17. In pneumonia with consolidated lobes, which position best improves oxygenation?
Show answer
18. A neonate requires precise low FiO₂ with minimal resistance. Best device?
Show answer
19. Which change decreases auto-PEEP in a ventilated patient with COPD?
Show answer
20. Which finding suggests need to escalate from Venturi mask to NRB or NIV?
Show answer
📝 Chapter 10 – Interactive Practice Quiz (Set 1: Questions 1–10)
Tap or click your answer to see immediate feedback with explanations.
1. A postoperative patient is somnolent with shallow breathing (RR 8/min). What does the ABG likely show?A. pH 7.49 / PaCO₂ 30B. pH 7.30 / PaCO₂ 58C. pH 7.41 / PaCO₂ 40D. pH 7.50 / HCO₃⁻ 18
2. What is the best first step for suspected mucus plugging in a ventilated patient?A. Increase FiO₂ to 1.0 onlyB. Assess airway and suctionC. Decrease tidal volumeD. Initiate sedation
3. Which sign indicates impending upper airway obstruction?A. Inspiratory stridorB. Fine crackles at lung basesC. Dullness to percussionD. Pleural friction rub
4. Which presentation is most consistent with pulmonary embolism?A. Fever, productive cough, lobar consolidationB. Sudden pleuritic chest pain, tachycardia, normal chest x-rayC. Gradual orthopnea with pink frothy sputumD. Purulent sputum with wheezing and prolonged expiration
5. In suspected tension pneumothorax on a ventilator, what is the priority?A. Immediate chest decompressionB. Obtain ABG firstC. Increase PEEPD. Wait for confirmatory CT scan
6. Which ventilator adjustment most effectively lowers PaCO₂ during volume control ventilation?A. Increase FiO₂B. Increase respiratory rateC. Increase tidal volumeD. Increase PEEP
7. Which oxygen delivery device is preferred to provide a precise 28% FiO₂ in a COPD patient?A. Simple mask at 6 L/minB. Venturi mask with 28% adapterC. Non-rebreather maskD. Nasal cannula at 6 L/min
8. Elevated plateau pressure with normal peak pressure suggests:A. Reduced lung complianceB. Increased airway resistanceC. Circuit water accumulationD. Cuff leak
9. Which infection control measure best reduces ventilator-associated pneumonia (VAP)?A. Routine scheduled deep suctioningB. Oral care with chlorhexidine and elevating head of bed 30–45°C. Keeping patient flat to prevent tube migrationD. Avoiding sedation holidays to prevent agitation
10. A spontaneously breathing patient uses accessory muscles and shows paradoxical abdominal movement. What is the priority?A. Provide ventilatory support (NIV or prepare for intubation)B. Administer 0.9% saline bolusC. Give diureticsD. Measure peak flow only Reset Quiz (clear selections)