Respiratory Therapist Prometric exam questions with answers

1. Question 1Arterial Blood Gases, Acid-Base Balance & Oxygenation Assessmenteasy

   A 64-year-old man is drowsy 6 hours after repeated intravenous morphine doses following hip surgery. Arterial blood gas on 2 L/min nasal cannula shows pH 7.24, PaCO2 62 mmHg (8.3 kPa) and HCO3- 26 mmol/L. Which interpretation is correct?

   1. AAcute, uncompensated respiratory acidosis
   2. BChronic, compensated respiratory acidosis
   3. CCombined respiratory and metabolic acidosis
   4. DMetabolic acidosis with respiratory compensation
   Show answer and explanation▾

   Answer: A. Acute, uncompensated respiratory acidosis

   The low pH with a raised PaCO2 identifies a primary respiratory acidosis, and the bicarbonate has risen only about 1 mmol/L per 10 mmHg rise in PaCO2, which is the expected acute buffering response. Chronic renal compensation would raise HCO3- by roughly 3.5 to 4 mmol/L per 10 mmHg, to about 31 mmol/L, with a pH closer to normal. A combined acidosis would require a bicarbonate below the expected value.

2. Question 2Mechanical Ventilation: Initiation, Management & Liberationhard

   A 52-year-old man with ARDS is on volume control with a tidal volume of 420 mL. At PEEP 14 cmH2O the plateau pressure is 29 cmH2O. PEEP is increased to 16 cmH2O with the same tidal volume and the plateau pressure rises to 33 cmH2O. Which interpretation of this PEEP trial is correct?

   1. ADriving pressure has risen and compliance fallen, suggesting overdistension; return to PEEP 14
   2. BDriving pressure is unchanged, so the higher PEEP has recruited lung and should be kept
   3. CThe response cannot be assessed without first changing the tidal volume
   4. DCompliance has improved because plateau pressure rose more than PEEP
   Show answer and explanation▾

   Answer: A. Driving pressure has risen and compliance fallen, suggesting overdistension; return to PEEP 14

   Driving pressure (plateau minus PEEP) rose from 15 to 17 cmH2O and static compliance fell from 28 to about 25 mL/cmH2O, so the extra PEEP overdistended lung rather than recruiting it. Successful recruitment would lower or maintain driving pressure and improve compliance. Lower driving pressure is independently associated with survival in ARDS, so the previous PEEP should be restored.

3. Question 3Mechanical Ventilation: Initiation, Management & Liberationhard

   A 26-year-old woman intubated for life-threatening asthma is on volume A/C: tidal volume 450 mL, rate 22/min, inspiratory flow 50 L/min, PEEP 5 cmH2O. Her blood pressure falls to 78/40 mmHg, the expiratory flow waveform does not return to zero before each breath, and an end-expiratory hold shows a total PEEP of 17 cmH2O. Which ventilator change is most appropriate?

   1. AIncrease applied PEEP to 17 cmH2O to match intrinsic PEEP
   2. BIncrease tidal volume to improve carbon dioxide clearance
   3. CReduce inspiratory flow to lower the peak airway pressure
   4. DReduce the set rate to lengthen expiratory time
   Show answer and explanation▾

   Answer: D. Reduce the set rate to lengthen expiratory time

   Dynamic hyperinflation with intrinsic PEEP raises intrathoracic pressure and reduces venous return, causing hypotension; the key fix is more expiratory time, achieved mainly by lowering the rate (and minute ventilation), accepting permissive hypercapnia. Reducing inspiratory flow lengthens inspiratory time and therefore shortens expiration, worsening air trapping. Matching applied PEEP to intrinsic PEEP mainly helps triggering in spontaneously breathing patients and would not relieve haemodynamic compromise here.

4. Question 4Oxygen Therapy, Medical Gas Delivery, Humidity & Aerosol Therapymedium

   A patient with COPD is placed on an air-entrainment (Venturi) mask set at 40% with an oxygen flow of 8 L/min. Using an air-to-oxygen entrainment ratio of about 3:1, what is the approximate total flow delivered to the patient?

   1. A11 L/min
   2. B40 L/min
   3. C24 L/min
   4. D32 L/min
   Show answer and explanation▾

   Answer: D. 32 L/min

   At 40% the mask entrains about 3 L of air for every 1 L of oxygen, so total flow is the oxygen flow multiplied by the sum of the ratio parts: 8 x (3 + 1) = 32 L/min. The figure of 24 L/min is the entrained air alone and forgets to add the source oxygen. Whether total flow meets the patient's peak inspiratory demand determines whether the delivered FIO2 stays fixed.

5. Question 5Pulmonary Function Testing, Diagnostic Procedures & Chest Imagingmedium

   A 61-year-old man has progressive exertional dyspnoea and fine bibasal inspiratory crackles. Pulmonary function tests show FEV1 62% predicted, FVC 58% predicted, FEV1/FVC 0.84, TLC 61% predicted and DLCO 42% predicted. Which condition best fits this pattern?

   1. ABilateral diaphragmatic weakness
   2. BIdiopathic pulmonary fibrosis
   3. CSevere kyphoscoliosis
   4. DEmphysema with hyperinflation
   Show answer and explanation▾

   Answer: B. Idiopathic pulmonary fibrosis

   A preserved or high FEV1/FVC with a reduced TLC confirms restriction, and the markedly reduced DLCO points to a parenchymal (interstitial) cause such as pulmonary fibrosis. Chest wall and neuromuscular restriction, such as kyphoscoliosis or diaphragm weakness, typically produce a normal or near-normal DLCO, especially when corrected for alveolar volume. Emphysema causes obstruction with a raised TLC.

6. Question 6Airway Management & Artificial Airwayseasy

   Immediately after an emergency orotracheal intubation, which method is the most reliable way to confirm that the tube is in the trachea?

   1. ABilateral breath sounds heard on auscultation
   2. BSymmetrical chest rise during bag ventilation
   3. CContinuous waveform capnography showing sustained exhaled CO2
   4. DMisting inside the tube during exhalation
   Show answer and explanation▾

   Answer: C. Continuous waveform capnography showing sustained exhaled CO2

   Resuscitation guidelines recommend continuous waveform capnography as the most reliable method to confirm and monitor tracheal tube placement, as a persistent CO2 waveform over several breaths is not produced by oesophageal placement. Auscultation, tube misting and chest rise are useful supporting signs but can all be misleading, for example breath sounds transmitted from gastric insufflation. A chest radiograph assesses depth, not tracheal versus oesophageal placement.

7. Question 7Airway Clearance, Lung Expansion & Pulmonary Rehabilitationeasy

   A 19-year-old with cystic fibrosis is being taught positive expiratory pressure (PEP) mask therapy. During active exhalation through the resistor, which manometer pressure range is the usual target?

   1. A30 to 40 cmH2O
   2. B45 to 60 cmH2O
   3. C2 to 5 cmH2O
   4. D10 to 20 cmH2O
   Show answer and explanation▾

   Answer: D. 10 to 20 cmH2O

   Conventional PEP therapy targets an expiratory pressure of about 10 to 20 cmH2O, which splints the airways open and encourages collateral ventilation so that air can get behind secretions. Pressures of only a few cmH2O give little airway splinting. Much higher pressures cause fatigue and are only used in the specialised high-pressure PEP technique, not routine therapy.

8. Question 8Respiratory Pharmacology & Medication Administrationmedium

   A 30-year-old woman with severe acute asthma has received continuous nebulised salbutamol for 2 hours. She now has a fine tremor, heart rate 128/min and a serum potassium of 2.9 mmol/L (baseline 4.1 mmol/L). What is the main mechanism of the fall in potassium?

   1. ABeta-2 stimulation increases renal tubular potassium excretion
   2. BHaemodilution from intravenous fluids given during treatment
   3. CBeta-2 stimulation drives potassium into cells via Na+/K+-ATPase
   4. DRespiratory alkalosis from hyperventilation shifts potassium into cells
   Show answer and explanation▾

   Answer: C. Beta-2 stimulation drives potassium into cells via Na+/K+-ATPase

   Beta-2 agonists activate Na+/K+-ATPase in skeletal muscle and shift potassium intracellularly, producing a predictable, dose-related fall in serum potassium within an hour of high-dose therapy. Alkalosis can also shift potassium, but the effect is small and many patients with severe asthma are not alkalotic. Potassium should be monitored and replaced during intensive bronchodilator therapy.

9. Question 9Neonatal & Pediatric Respiratory Caremedium

   A term newborn remains apnoeic after drying, warming, positioning the airway and tactile stimulation. At 60 seconds of age the heart rate is 80/min. What is the most appropriate next step?

   1. AGive free-flow 100% oxygen and continue stimulation
   2. BBegin chest compressions coordinated with ventilation at 3:1
   3. CStart positive-pressure ventilation using 21% oxygen
   4. DGive intravenous adrenaline via an umbilical venous catheter
   Show answer and explanation▾

   Answer: C. Start positive-pressure ventilation using 21% oxygen

   Apnoea or a heart rate below 100/min after the initial steps is the indication for positive-pressure ventilation, which is the single most effective intervention in newborn resuscitation; term and late-preterm infants start with 21% oxygen. Compressions are only indicated if the heart rate stays below 60/min despite 30 seconds of effective ventilation. Free-flow oxygen does not ventilate an apnoeic infant.

10. Question 10Neonatal & Pediatric Respiratory Carehard

    A term infant born through meconium-stained fluid has a right-hand SpO2 of 96% and a foot SpO2 of 81% on FIO2 1.0. Echocardiography shows a structurally normal heart. Which explanation and treatment are most appropriate?

    1. AProbe artefact from poor foot perfusion; repeat the readings only
    2. BRight-to-left ductal shunting from pulmonary hypertension; consider inhaled nitric oxide
    3. CDuct-dependent cyanotic heart disease; start intravenous prostaglandin E1
    4. DLeft-to-right ductal shunting; start an intravenous prostaglandin infusion
    Show answer and explanation▾

    Answer: B. Right-to-left ductal shunting from pulmonary hypertension; consider inhaled nitric oxide

    A pre-ductal saturation clearly higher than the post-ductal value indicates deoxygenated blood crossing the ductus arteriosus from the pulmonary artery into the descending aorta, the hallmark of persistent pulmonary hypertension of the newborn. With a structurally normal heart, inhaled nitric oxide (typically 20 ppm) is indicated for hypoxaemic respiratory failure in term infants. A left-to-right shunt would not lower post-ductal saturation, and prostaglandin is for duct-dependent lesions, which echo has excluded.

11. Question 11Critical Care, Emergency Response, Resuscitation & Transportmedium

    During an adult in-hospital cardiac arrest with an endotracheal tube in place, the end-tidal CO2 has been 12 to 15 mmHg during chest compressions. It abruptly rises to 40 mmHg with no change in ventilation. What is the most likely explanation?

    1. AReturn of spontaneous circulation
    2. BHyperventilation by the person squeezing the bag
    3. CDisplacement of the tube into the oesophagus
    4. DCompressor fatigue reducing the quality of CPR
    Show answer and explanation▾

    Answer: A. Return of spontaneous circulation

    End-tidal CO2 during CPR reflects pulmonary blood flow, so a sudden sustained rise to normal values is an early sign of return of spontaneous circulation and should prompt a pulse and rhythm check. Hyperventilation lowers end-tidal CO2, as does poorer compression quality. Oesophageal displacement causes the CO2 waveform to disappear.

12. Question 12Equipment Assembly, Troubleshooting & Quality Controlmedium

    An E cylinder with a cylinder factor of 0.28 L/psi reads 1,800 psi. A patient needs 4 L/min of oxygen during transport. Approximately how long will the cylinder last if used until empty?

    1. A126 minutes
    2. B63 minutes
    3. C252 minutes
    4. D45 minutes
    Show answer and explanation▾

    Answer: A. 126 minutes

    Duration equals gauge pressure multiplied by the cylinder factor, divided by the flow: 1,800 x 0.28 / 4 = 126 minutes. Halving or doubling this reflects arithmetic or factor errors. In practice a safety reserve is kept, so the usable time is shorter and a spare cylinder should accompany longer transports.

13. Question 13Patient Safety, Infection Prevention, Professionalism, Ethics & Scope of Practiceeasy

    Which intervention is part of evidence-based bundles for preventing ventilator-associated pneumonia in adults?

    1. AKeeping the backrest flat during enteral feeding
    2. BChanging ventilator circuits routinely every 24 hours
    3. CElevating the head of the bed to 30 to 45 degrees
    4. DInstilling saline routinely before each suction pass
    Show answer and explanation▾

    Answer: C. Elevating the head of the bed to 30 to 45 degrees

    Semi-recumbent positioning reduces aspiration of gastric contents and oropharyngeal secretions and is a core VAP prevention measure, alongside daily sedation interruption and readiness-to-wean assessment. Routine circuit changes do not reduce VAP and circuits should be changed only when visibly soiled or malfunctioning. Routine saline instillation is not recommended and may dislodge organisms into the lower airway.

14. Question 14Arterial Blood Gases, Acid-Base Balance & Oxygenation Assessmenthard

    A 22-year-old is brought in after an opioid overdose. Breathing room air at sea level (barometric pressure 760 mmHg), the ABG shows pH 7.18, PaCO2 80 mmHg and PaO2 48 mmHg. Assuming a respiratory quotient of 0.8, which conclusion is correct?

    1. AThe A-a gradient is about 100 mmHg, indicating V/Q mismatch
    2. BThe A-a gradient is normal, so hypoxaemia is explained by hypoventilation alone
    3. CThe A-a gradient is widened, indicating a diffusion defect
    4. DThe A-a gradient is about 50 mmHg, indicating an intrapulmonary shunt
    Show answer and explanation▾

    Answer: B. The A-a gradient is normal, so hypoxaemia is explained by hypoventilation alone

    The alveolar gas equation gives PAO2 = 0.21 x (760 - 47) - 80/0.8, which is about 150 - 100 = 50 mmHg, so the A-a gradient is only about 2 mmHg. A normal gradient means the hypoxaemia is fully accounted for by alveolar hypoventilation and should correct with ventilation (for example after naloxone). A widened gradient would suggest aspiration, shunt or V/Q mismatch, which this calculation does not support.

15. Question 15Patient Assessment & Clinical Data Evaluationmedium

    A 70-year-old woman presents with dyspnoea. Over the left lower hemithorax there is stony dull percussion, absent breath sounds and reduced tactile fremitus, and the trachea is deviated to the right. Which finding is most likely?

    1. ALeft lower lobe consolidation
    2. BLarge left pleural effusion
    3. CLeft tension pneumothorax
    4. DLeft lower lobe collapse
    Show answer and explanation▾

    Answer: B. Large left pleural effusion

    Stony dullness with absent breath sounds and reduced fremitus, plus tracheal shift away from the affected side, is the classic picture of a large pleural effusion. Lobar collapse pulls the trachea toward the abnormal side, and consolidation gives bronchial breath sounds with increased fremitus. A pneumothorax is hyperresonant rather than dull.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.