20 free NBRC RT Exam practice questions

Correct answer: C · Carboxyhemoglobin measured by CO-oximetry on a sample of his blood

The CDC's clinical guidance on carbon monoxide poisoning says the conventional two-wavelength pulse oximeter is not accurate when carboxyhemoglobin is present, and that the key to confirming the diagnosis is measuring the carboxyhemoglobin level, which hospital labs usually do with a CO-oximeter on blood samples. A repeat reading on another finger uses the same two-wavelength method, so it cannot reveal carboxyhemoglobin. A PaO2 alone does not measure carboxyhemoglobin either, so it cannot confirm or exclude the diagnosis. A chest radiograph may matter for other injuries, but it measures nothing about carbon monoxide in the blood.

Look for this next time: Standard pulse oximetry is not accurate when carboxyhemoglobin is present; confirm suspected CO poisoning with CO-oximetry.

Correct answer: A · Acute respiratory acidosis with the small HCO3 rise expected early on

The Merck Manual defines acidemia as a pH below 7.35 and respiratory acidosis as a primary rise in PCO2. For each 10 mm Hg rise in PCO2, bicarbonate rises about 1–2 mEq/L in acute respiratory acidosis and about 3–4 mEq/L in chronic respiratory acidosis. Her PaCO2 is about 22 mm Hg above 40, so an acute process predicts a bicarbonate a few points above normal, and 26 fits; full chronic compensation would push it into the low 30s. A metabolic acidosis would need a low bicarbonate and would lower the PaCO2, not raise it. A metabolic alkalosis would raise the pH, and hers is 7.25.

Look for this next time: A high PaCO2 with low pH and a bicarbonate only slightly raised points to acute respiratory acidosis.

Correct answer: D · 120 mm Hg

The P/F ratio divides the PaO2 by the FIO2 written as a decimal, so 72 divided by 0.60 gives 120 mm Hg. Multiplying the two values instead of dividing gives about 43. Dividing by 60, the FIO2 written as a percentage, gives 1.2. Dividing by 0.40, the share of the gas that is not oxygen, gives 180. The RT Detailed Content Outline lists the P/F ratio among the cardiopulmonary calculations, next to the SpO2/FIO2 ratio and the oxygenation index, so expect to compute it from given values rather than read it from a monitor.

Look for this next time: P/F ratio = PaO2 ÷ FIO2 as a decimal; a PaO2 of 72 mm Hg on 0.60 gives 120.

Correct answer: B · Suction the endotracheal tube and check the tube for kinks or biting

The Merck Manual's overview of mechanical ventilation explains that the difference between peak and plateau pressure is the resistive pressure, and that a high resistive pressure suggests a kinked endotracheal tube, a tube plugged with secretions, an intraluminal mass, or bronchospasm. Here the gap grew to 21 cm H2O while the plateau did not move, and rhonchi point to secretions, so suctioning and checking the tube come first. A pneumothorax lowers compliance and would raise the plateau as well. Raising the alarm limit silences the warning without fixing the cause. More PEEP targets collapsed alveoli, not a resistance problem, and would raise the pressures further.

Look for this next time: A rising peak pressure with a steady plateau points to airway resistance: secretions, a kinked tube, or bronchospasm.

Correct answer: D · Leave it in place and change it only when soiled or malfunctioning

The CDC's 2003 Guidelines for Preventing Health-Care-Associated Pneumonia say not to change the breathing circuit routinely on the basis of how long it has been used, and to change it when it is visibly soiled or mechanically malfunctioning, a Category IA recommendation. This circuit is neither, so it stays in place. A 48-hour change, a weekly change, and a change at each shift are all schedules based on duration of use. The shift-change option adds a second error: the same guideline says to drain and discard condensate periodically while taking care that it does not drain toward the patient.

Look for this next time: Change a ventilator circuit when it is visibly soiled or malfunctioning, not on a schedule based on duration of use.

Correct answer: A · Assess him, check the waveform and probe, and move it to a warmer site

The FDA lists poor circulation, skin temperature, skin pigmentation, skin thickness, tobacco use, and fingernail polish among the factors that can affect a pulse oximeter reading, and it advises not to rely only on the oximeter but to consider how the person is doing. Cold fingers and an erratic waveform in a comfortable, talking patient point to a poor signal, so the first step is to assess him and fix the probe site; a low value that persists then needs treatment and a blood gas. Switching to a non-rebreather treats a number that may be artifact. Charting 81% records a doubtful value as fact. Skin color cannot replace measurement.

Look for this next time: Before acting on a sudden low SpO2, assess the patient and check the waveform and probe site.

Correct answer: B · Lower the tidal volume within 4–8 mL/kg PBW until plateau is below 30

The 2017 ATS/ESICM/SCCM guideline strongly recommends lower tidal volumes of 4–8 mL/kg of predicted body weight together with a plateau pressure below 30 cm H2O. At 560 mL he receives 8 mL/kg of predicted body weight, the top of the range, while his plateau of 34 breaks the second condition, so the volume comes down within the range. Keeping 560 mL meets only half of the recommendation. Using his actual weight would raise the volume, because the range is set by predicted body weight. Inspiratory flow changes the resistive part of the peak pressure, while the plateau is measured during a no-flow hold, so faster flow cannot fix it.

Look for this next time: In ARDS, keep tidal volume within 4–8 mL/kg of predicted body weight and plateau pressure below 30 cm H2O.

Correct answer: C · Start bilevel noninvasive ventilation and reassess her closely

The 2017 ERS/ATS guideline recommends bilevel noninvasive ventilation for acute respiratory failure leading to acute or acute-on-chronic respiratory acidosis, with a pH of 7.35 or lower, caused by a COPD exacerbation. It also recommends a trial of bilevel NIV in patients thought to need intubation unless they are immediately deteriorating, and she is alert and stable. CPAP alone is the guideline's alternative for cardiogenic pulmonary edema, not its choice for COPD. A pH below 7.35 is the threshold for NIV, not for going straight to intubation. Holding support would fit only hypercapnia without acidosis, where the guideline suggests not using NIV; her pH is 7.29.

Look for this next time: For a COPD exacerbation with respiratory acidosis (pH 7.35 or lower), start bilevel NIV unless the patient is immediately deteriorating.

Correct answer: A · A clinical check plus carbon dioxide found in the gas he exhales

The ASA Standards for Basic Anesthetic Monitoring require that correct positioning of an endotracheal tube or supraglottic airway be verified both by clinical assessment and by identifying carbon dioxide in the expired gas, with continual quantitative end-tidal carbon dioxide analysis, such as capnography, from placement onward. Equal breath sounds are part of the clinical assessment, but alone they leave out the carbon dioxide check. An SpO2 measures oxygenation, not where the tube sits, and the standard does not list it as confirmation. Fogging in the tube is another clinical sign, so it still lacks the required carbon dioxide identification.

Look for this next time: Confirm tube position with clinical assessment plus exhaled carbon dioxide, then monitor end-tidal CO2 continually.

Correct answer: D · Avoid stopping it abruptly, and watch her oxygenation closely

The INOmax prescribing information warns that abrupt discontinuation may lead to worsening oxygenation and increasing pulmonary artery pressure, called rebound pulmonary hypertension, and says to reinstate the drug immediately if that happens. So the therapy is reduced and stopped without an abrupt cutoff while oxygenation is watched. Stopping at once is the abrupt discontinuation the label warns about, and raising the FIO2 at the same moment does not make the stop any less abrupt. Continuing it without monitoring inspired NO2 conflicts with the label, which calls for monitoring PaO2 and inspired NO2 for as long as the drug is given.

Look for this next time: Never stop inhaled nitric oxide abruptly: rebound pulmonary hypertension can follow.

Correct answer: C · Extubate him directly to preventive noninvasive ventilation (NIV)

The 2017 ATS/CHEST guideline strongly recommends extubation to preventive noninvasive ventilation for patients at high risk for extubation failure who have been ventilated for more than 24 hours and have passed a breathing trial, and its remarks name hypercapnia and COPD among the high-risk features. He meets every condition. Keeping him intubated after he passed the trial delays the extubation the guideline supports. Waiting to start NIV until he fails conflicts with the 2017 ERS/ATS guideline, which suggests not using NIV to treat established post-extubation respiratory failure. Room air ignores the high risk that the guideline asks clinicians to plan for.

Look for this next time: After a passed breathing trial, extubate a high-risk patient ventilated over 24 hours directly to preventive NIV.

Correct answer: B · Protocolized rehabilitation for early mobility, with minimal sedation

For acutely hospitalized adults ventilated for more than 24 hours, the 2017 ATS/CHEST guideline suggests protocolized rehabilitation directed toward early mobilization and protocols that attempt to minimize sedation. Both are conditional recommendations, and both apply to a stable patient on day 3. Bed rest under deep sedation until extubation postpones the mobilization and adds the sedation the guideline tries to minimize. Waiting until she leaves the ICU delays rehabilitation well past the point the guideline addresses. Deepening sedation during therapy runs against the sedation-minimizing protocols and makes active participation harder.

Look for this next time: For adults ventilated over 24 hours, the 2017 ATS/CHEST guideline suggests early, protocolized mobilization with minimal sedation.

Correct answer: B · A cuff leak test, with steroids before extubation if she fails it

The 2017 ATS/CHEST guideline suggests a cuff leak test for ventilated adults who meet extubation criteria and are judged at high risk for post-extubation stridor, and it suggests systemic steroids at least 4 hours before extubation for patients who fail the test, without requiring a repeat test. She fits that group, so the cuff leak test is the information to gather. A chest radiograph is not the guideline's test for laryngeal swelling. Skipping the test ignores the high-risk judgment the team has already made. A maximal inspiratory pressure measures breathing muscle strength, not airway swelling.

Look for this next time: Information gathering: check a cuff leak test before extubating a patient at high risk for post-extubation stridor.

Correct answer: D · Lower the set rate so that each breath gets more time for exhalation

The Merck Manual describes intrinsic PEEP as present when expiratory flow continues until the next breath, measures it with an end-expiratory hold, and lists ways to reduce it: lower the respiratory rate to lengthen exhalation, shorten inspiratory time by increasing inspiratory flow, and treat the airflow obstruction, with an I:E ratio of 1:4 or more in COPD exacerbations. Lowering the set rate gives each breath more time to empty. A higher rate shortens exhalation and adds to the trapped gas. A larger tidal volume leaves more gas to exhale in the same time. A slower inspiratory flow lengthens inspiration and steals time from exhalation.

Look for this next time: Decision making: reduce auto-PEEP by giving more time to exhale, for example with a lower set rate.

Correct answer: A · Prone positioning for more than 12 hours each day

The 2017 ATS/ESICM/SCCM guideline strongly recommends prone positioning for more than 12 hours a day in adults with severe ARDS, so it is the next step for her. The same guideline strongly recommends against the routine use of high-frequency oscillatory ventilation in moderate or severe ARDS. A larger tidal volume would break the 4–8 mL/kg of predicted body weight range and push the plateau pressure toward the 30 cm H2O limit she already sits close to. Two hours of prone positioning each morning falls far short of the more-than-12-hours duration the recommendation names.

Look for this next time: Decision making: in severe ARDS, prone positioning for more than 12 hours a day is a strong recommendation.

Correct answer: C · Forced vital capacity measured at the bedside every 6 to 8 hours

The Merck Manual says forced vital capacity should be measured every 6 to 8 hours in Guillain-Barré syndrome so that breathing can be assisted if needed, and that a vital capacity below 15 mL/kg indicates endotracheal intubation; it also names inability to lift the head off the pillow as a danger sign. Serial vital capacity is therefore the measure to recommend. Pulse oximetry tracks oxygenation, not muscle strength, so a normal value does not show how close he is to that threshold. A chest radiograph shows the lungs, not the strength of the muscles that move them. One peak flow each morning is far less frequent than the interval the manual gives.

Look for this next time: Information gathering: in Guillain-Barré syndrome, track breathing muscle strength with forced vital capacity every 6 to 8 hours.

Correct answer: D · CPAP or bilevel noninvasive ventilation through a face mask

The 2017 ERS/ATS guideline recommends either bilevel noninvasive ventilation or CPAP for acute respiratory failure due to cardiogenic pulmonary edema, and it recommends a trial of NIV for patients thought to need intubation unless they are immediately deteriorating. She is alert, cooperative, and has no contraindication, so mask CPAP or bilevel fits. Incentive spirometry is a lung-expansion exercise and does not support a patient in acute respiratory failure. Going straight to intubation skips the NIV trial the guideline recommends. The crackles come from fluid in the lungs in heart failure, and an inhaled bronchodilator is not the guideline's treatment for this condition.

Look for this next time: Decision making: for acute cardiogenic pulmonary edema, the 2017 ERS/ATS guideline recommends CPAP or bilevel NIV.

Correct answer: B · Alert the team to a likely tension pneumothorax for decompression now

The Merck Manual says tension pneumothorax most often occurs in patients receiving positive-pressure ventilation, that sudden hypotension in a ventilated patient should prompt the question, and that absent breath sounds and a trachea shifted to the opposite side are signs. It says the diagnosis is clinical and should not wait for a radiograph, with immediate needle decompression followed by a chest tube, so the therapist alerts the team now. Waiting for an x-ray on arrival is the delay the manual warns against. Secretions raise the peak pressure, not the plateau, and here both rose. A larger tidal volume adds pressure to a chest already under tension.

Look for this next time: Decision making: sudden hypotension with absent breath sounds and a shifted trachea on a ventilator calls for immediate decompression, not an x-ray.

Correct answer: A · Racemic epinephrine and a corticosteroid, then at least 2 hours of observation

Stridor at rest places him beyond mild croup. The Merck Manual recommends nebulized racemic epinephrine mainly for moderate to severe croup, adds a corticosteroid for these children, and says they should be monitored in a medical setting for at least 2 hours after the epinephrine because its effects are transient. Cool mist at home fits only mild disease, and the manual says humidifiers have not been shown to alter the course of the illness. Discharging him as soon as the stridor fades ignores the 2-hour observation. Albuterol is not among the croup treatments the manual lists, and his SpO2 of 95% needs no oxygen.

Look for this next time: Decision making: croup with stridor at rest calls for racemic epinephrine, a corticosteroid, and at least 2 hours of observation.

Correct answer: C · Measure lung volumes, because restriction requires a low TLC

The Merck Manual defines restrictive disorders by a reduction in lung volume, specifically a total lung capacity below the lower limit of normal, and says a decreased FEV1/FVC ratio indicates obstruction. A reduced FVC with a normal ratio is consistent with restriction, but the diagnosis rests on lung volumes, so the therapist recommends measuring them. Reporting restriction from the FVC alone skips that step. An obstructive disorder needs a reduced FEV1/FVC ratio, and his ratio is normal. A bronchodilator study tests the response of the airways, which the manual ties to airway hyperresponsiveness, and it cannot show a low total lung capacity.

Look for this next time: Information gathering: a low FVC with a normal FEV1/FVC ratio suggests restriction, but confirming it takes a low TLC on lung volumes.