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HLT-RESP80-09 · Lesson 2 · 80 clock hours · practice

TMC Content Domain Deep-Review: Patient Assessment, Therapeutics, and Equipment

Objective. Students will correctly answer at least 75% of practice questions across all TMC content domains—including patient data evaluation, clinical problem-solving, equipment operation, and therapeutic procedures—through structured review sessions and targeted remediation.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Why This Review Phase Matters

The Therapist Multiple-Choice (TMC) Examination, administered by the National Board for Respiratory Care (NBRC), is the gateway credential for every entry-level respiratory therapist in the United States. Passing at the CRT level demonstrates entry-level competency; a higher cut score on the same exam qualifies you to sit the Clinical Simulation Examination (CSE) for the RRT credential. Your state licensing board then requires evidence of NBRC credentialing before issuing the legal license to practice. This means your performance on the TMC has a direct chain of consequences: exam score → credential → state license → legal right to work.

This lesson organizes your final preparation into focused domain blocks so that no area of the content outline is left under-practiced. The target is straightforward: answer at least 75% of practice questions correctly in every domain before moving forward.

The Major TMC Content Domains

The NBRC publishes a Detailed Content Outline listing every topic the TMC can test. The broad domains include:

Spend approximately 8–10 study hours on each domain, prioritizing any area where your tracking spreadsheet shows below-75% accuracy.

ABG Interpretation: A Systematic Approach

ABG questions appear across multiple domains and are among the highest-yield items on the TMC. Use a consistent four-step algorithm every time:

1. pH – Is it normal (7.35–7.45), acidotic (<7.35), or alkalotic (>7.45)?

2. PaCO₂ – Is it normal (35–45 mmHg)? Elevated CO₂ = respiratory acidosis; low CO₂ = respiratory alkalosis.

3. HCO₃⁻ – Is it normal (22–26 mEq/L)? Low HCO₃⁻ = metabolic acidosis; high HCO₃⁻ = metabolic alkalosis.

4. Compensation – Does the non-primary component move in the same direction as pH change? If so, compensation is present.

Finally, assess oxygenation: PaO₂ (normal ~80–100 mmHg on room air) and SaO₂ (normal ≥95%).

Never skip the algorithm, even when the answer seems obvious. Rushing through ABG questions is a common source of avoidable errors.

Ventilator Management Essentials

Mechanical ventilation questions test both conceptual understanding and practical troubleshooting. Know these principles:

Pharmacology: Drug Classes to Know

The TMC tests recognition of drug classes more than brand-specific names. Focus on:

Know the mechanism of action, primary indication, route of delivery, and key adverse effects for each class.

Pulmonary Function Testing Interpretation

PFT questions often present numerical data alongside flow-volume loops. Key patterns:

Post-bronchodilator improvement of ≥12% and ≥200 mL in FEV₁ indicates significant reversibility, supporting an asthma diagnosis.

Infection Control: Non-Negotiable Safety Practice

Respiratory therapists work in high-risk environments. Infection control questions on the TMC are also patient safety imperatives in clinical practice:

Ventilator-associated pneumonia (VAP) prevention bundles—head-of-bed elevation, oral care, and cuff pressure monitoring—are standard RT responsibilities.

Using Your Domain-Tracking Spreadsheet

After every 40-question practice set, record your percent correct per domain. When a domain falls below 75%, do not simply repeat questions—go back to the relevant chapter in Egan's or your review text, re-read the concept, then attempt a fresh question set. Write out the rationale for every question you missed. This active correction process builds durable understanding rather than answer memorization.

Key terms10

TMC ExaminationThe Therapist Multiple-Choice Examination administered by the NBRC; the standardized test required for CRT credentialing and, at a higher cut score, qualification to sit the CSE for the RRT credential.
Arterial Blood Gas (ABG)A laboratory measurement of pH, PaCO₂, PaO₂, HCO₃⁻, and oxygen saturation from an arterial blood sample, used to assess a patient's acid-base balance and oxygenation status.
FEV₁/FVC RatioThe fraction of forced vital capacity exhaled in the first second; a ratio below 0.70 after bronchodilation indicates airflow obstruction consistent with an obstructive pulmonary pattern.
Lung-Protective VentilationA mechanical ventilation strategy using low tidal volumes (generally 4–8 mL/kg of predicted body weight) and limited plateau pressures to reduce ventilator-induced lung injury, particularly in ARDS.
Short-Acting Beta-2 Agonist (SABA)A class of bronchodilator medication (e.g., albuterol) that rapidly relaxes airway smooth muscle; used as first-line rescue therapy during acute bronchospasm.
Transmission-Based PrecautionsInfection control measures added on top of standard precautions when a patient's known or suspected pathogen requires additional barriers; categories include airborne, droplet, and contact precautions.
Ventilator-Associated Pneumonia (VAP)A hospital-acquired pneumonia developing in a patient who has been on mechanical ventilation for 48 hours or more; prevention is a core respiratory therapist responsibility.
Flow-Volume LoopA graphic display of airflow plotted against lung volume during a maximal forced inspiration and expiration; the shape of the loop helps identify obstructive, restrictive, or upper-airway abnormalities.
Rapid Shallow Breathing Index (RSBI)A weaning parameter calculated by dividing respiratory rate by tidal volume (in liters); lower values generally predict more successful weaning from mechanical ventilation.
Predicted Body Weight (PBW)An estimated weight calculated from a patient's height and sex, used—rather than actual weight—to set initial tidal volume targets during lung-protective mechanical ventilation.

Worked examples4

1. A patient's ABG shows: pH 7.28, PaCO₂ 54 mmHg, HCO₃⁻ 24 mEq/L, PaO₂ 62 mmHg on room air. Interpret the results.
  1. Step 1 – Assess pH: 7.28 is below 7.35, so the primary disorder is acidosis.
  2. Step 2 – Assess PaCO₂: 54 mmHg is above 45 mmHg, indicating CO₂ retention. This is consistent with respiratory acidosis, which matches the low pH—respiratory acidosis is the primary problem.
  3. Step 3 – Assess HCO₃⁻: 24 mEq/L is within the normal range (22–26 mEq/L), indicating no primary metabolic disorder and no significant metabolic compensation yet (acute process).
  4. Step 4 – Assess oxygenation: PaO₂ of 62 mmHg is below 80 mmHg, indicating mild-to-moderate hypoxemia.
  5. Step 5 – Conclude: Acute uncompensated respiratory acidosis with hypoxemia. Clinical priority is to improve ventilation (reduce PaCO₂) and supplement oxygen.
Answer: Acute uncompensated respiratory acidosis (pH 7.28, PaCO₂ 54 mmHg, HCO₃⁻ normal) with hypoxemia (PaO₂ 62 mmHg).
2. A male patient is 5 ft 10 in tall (70 inches). Using the simplified PBW formula for males—PBW (kg) = 50 + 2.3 × (height in inches − 60)—calculate the PBW and the target tidal volume range for lung-protective ventilation (6–8 mL/kg PBW).
  1. Step 1 – Calculate PBW: PBW = 50 + 2.3 × (70 − 60) = 50 + 2.3 × 10 = 50 + 23 = 73 kg.
  2. Step 2 – Calculate low end of tidal volume range: 6 mL/kg × 73 kg = 438 mL.
  3. Step 3 – Calculate high end of tidal volume range: 8 mL/kg × 73 kg = 584 mL.
  4. Step 4 – Set initial tidal volume within 438–584 mL, targeting the lower end (6 mL/kg = 438 mL) in confirmed ARDS per lung-protective guidelines.
Answer: PBW = 73 kg; target tidal volume range is 438–584 mL; use ~438 mL (6 mL/kg) for lung-protective ventilation in ARDS.
3. A patient's spirometry shows: FVC = 3.20 L (predicted 4.00 L, 80% predicted), FEV₁ = 1.85 L (predicted 3.20 L, 58% predicted), FEV₁/FVC = 0.58. After bronchodilator: FEV₁ = 2.15 L. Interpret the pattern and assess reversibility.
  1. Step 1 – Assess FEV₁/FVC ratio: 0.58 is below 0.70, indicating airflow obstruction.
  2. Step 2 – Assess severity of obstruction: FEV₁ is 58% of predicted, indicating moderate obstruction.
  3. Step 3 – Assess FVC: 80% of predicted is within normal limits, consistent with an obstructive (not restrictive) pattern.
  4. Step 4 – Assess bronchodilator response: Post-bronchodilator FEV₁ = 2.15 L. Change = 2.15 − 1.85 = 0.30 L (300 mL). Percent change = (0.30 / 1.85) × 100 = 16.2%. Both ≥200 mL and ≥12% thresholds are met.
  5. Step 5 – Conclude: Moderate obstructive pattern with significant bronchodilator reversibility, consistent with asthma.
Answer: Moderate obstructive ventilatory defect (FEV₁/FVC 0.58, FEV₁ 58% predicted) with significant reversibility (FEV₁ improved 300 mL / 16.2% post-bronchodilator), consistent with asthma.
4. A patient on volume-control mechanical ventilation suddenly triggers a high-pressure alarm. List the steps to troubleshoot in the correct clinical order.
  1. Step 1 – Immediately assess the patient: Look for signs of distress, cyanosis, or decreased chest rise. Patient safety comes first—if in doubt, disconnect from ventilator and manually ventilate with a bag-valve-mask.
  2. Step 2 – Check the airway: Is the patient biting the endotracheal tube? Is the tube kinked or displaced? Suction to assess and clear secretions if present.
  3. Step 3 – Auscultate the chest: Unilateral breath sounds suggest possible right mainstem intubation or pneumothorax. Wheezing suggests bronchospasm.
  4. Step 4 – Check the ventilator circuit: Look for water accumulation in the tubing, kinked circuit, or disconnected components.
  5. Step 5 – Review the alarm limit setting: Confirm the high-pressure limit is set appropriately (typically 10–15 cmH₂O above the patient's peak inspiratory pressure).
  6. Step 6 – Report findings and intervene: Treat the identified cause (suction, reposition tube, administer bronchodilator for bronchospasm, notify physician for suspected pneumothorax) and document.
Answer: Troubleshoot in this order: assess the patient and provide manual ventilation if needed → check the airway → auscultate → inspect the circuit → review alarm settings → treat the identified cause and document.

The math in this lesson2

Learners compute percent change in FEV₁ after bronchodilator to judge reversibility.
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Brush up in the math halls at newSchoolWorks.com:
In class: Rotating domain-focused review blocks (approximately 8–10 hours each): instructor delivers focused review of high-yield concepts for each major TMC domain (e.g., arterial blood gas interpretation, ventilator management, airway pharmacology, pulmonary function testing, neonatal/pediatric care, disease management, infection control), using case vignettes from the review text and projected NBRC-style questions; students answer questions live using individual response cards, and the group discusses rationale for correct and incorrect options. · Daily 40-question timed practice sets organized by domain; students score each set, enter results into a running domain-tracking spreadsheet, flag questions answered incorrectly for re-study, and complete a brief written rationale for each corrected answer—reinforcing understanding rather than memorization. · Peer teach-back sessions: pairs of students are assigned one subdomain each (e.g., interpreting flow-volume loops, setting initial ventilator parameters for ARDS) and must teach it back to the class using a whiteboard explanation and two original practice questions with answer rationale; class evaluates accuracy and clarity using a provided checklist.
Materials: Egan's Fundamentals of Respiratory Care; NBRC-aligned review text; domain-tracking spreadsheet template; NBRC Detailed Content Outline; pulmonary function testing reference values; ABG interpretation algorithm card; ventilator parameter quick-reference; pharmacology drug-class summary sheet; projector; response cards.
Check: Running domain-tracking spreadsheet reviewed by instructor at midpoint (end of hour 60 of this lesson) and at lesson end; each domain must reach ≥75% average correct on practice sets before the student advances to CSE preparation. Students scoring below 75% in any domain complete targeted remediation reading and a second 20-question domain set before proceeding.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Patient Data Evaluation / ABG Interpretation
1. A patient with a history of COPD presents with increased shortness of breath. ABG on 2 L/min nasal cannula: pH 7.32, PaCO₂ 60 mmHg, HCO₃⁻ 30 mEq/L, PaO₂ 55 mmHg. Which interpretation is correct?
Infection Control and Safety
2. A respiratory therapist enters a patient's room to deliver an aerosol treatment and notices the contact precautions sign on the door. Which personal protective equipment must the therapist don before entering?
Therapeutics / Mechanical Ventilation
3. A patient on volume-control ventilation for ARDS (height 5 ft 8 in, male) is currently set at a tidal volume of 700 mL. Using PBW = 50 + 2.3 × (height in inches − 60), what is the most appropriate adjustment?
Pulmonary Function Testing
4. During spirometry, a patient produces a flow-volume loop with a markedly scooped (concave) expiratory limb, reduced FEV₁, and a normal FVC. Which pattern does this most likely represent?
Therapeutics / Airway Pharmacology
5. A patient with acute severe asthma is not improving after two doses of a short-acting beta-2 agonist. Which additional inhaled medication class is most appropriate to add?
Equipment Operation and Troubleshooting / Patient Safety
6. A mechanically ventilated patient suddenly develops absent breath sounds on the left, tracheal deviation to the right, and a high-pressure alarm. The most urgent action is:
Neonatal and Pediatric Care
7. A premature neonate delivered at 28 weeks gestation develops grunting, nasal flaring, and retractions shortly after birth. Chest X-ray shows a diffuse ground-glass appearance. Which treatment is most specifically indicated for the underlying pathophysiology?
Therapeutics / Mechanical Ventilation
8. When assessing a patient's readiness to wean from mechanical ventilation, the rapid shallow breathing index (RSBI) is calculated as:
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