10 free Paramedic practice questions: Ventilator Management and Advanced Oxygenation

The average of the measured weight and the predicted weight for this height: Averaging still drags the volume upward with body fat that has no lung attached to it.

The adjusted weight used for medication dosing in a large patient: Adjusted weight belongs to drug dosing, where the medication distributes into tissue. Tidal volume answers to lung size instead.

The measured weight of 140 kilograms, which reflects the current oxygen demand: Oxygen demand is met by the fraction of inspired oxygen and PEEP, not by stretching the lungs past their size.

Serial blood pressure measurement at three-minute intervals during sedation: Blood pressure changes late in hypoventilation, well after the carbon dioxide has climbed and often after the patient has stopped breathing.

Repeat pulse oximetry readings every two minutes throughout the procedure: Repeating the same measurement more often does not make it report carbon dioxide. The saturation will read 100% either way.

Continuous cardiac monitoring with attention to the development of bradycardia: Bradycardia from carbon dioxide retention is a late sign. By the time the rate falls, the chance to intervene early has passed.

Begin chest compressions immediately: A sudden loss of the waveform to zero is a genuine cardiac arrest sign, and in a patient without a confirmed pulse it would demand an immediate pulse check. The question has already done that check for you and reports a strong carotid pulse. Compressing a perfusing patient is not harmless, and more importantly it treats a circulation problem this patient does not have while a possibly displaced tube goes unaddressed.

Replace the sensor and continue transport: Equipment failure is a real cause of a flat capnography trace: a disconnected sampling line, a sensor fouled by moisture or secretions, a cable that has worked loose, so this will sometimes turn out to be the answer. It is the most dangerous first assumption, though, because if you are wrong the patient is being ventilated into the esophagus or not at all while you swap parts. Check the patient and the tube first; a device that is genuinely broken will still be broken thirty seconds later.

Increase the ventilation rate and reassess: Adjusting the rate is how you respond to a value trending the wrong way in a patient who is being ventilated: a rising EtCO2 from hypoventilation, for example. It assumes gas is still moving through the tube, and a reading of zero tells you it is not. Ventilating faster through a tube that is displaced, blocked, or disconnected delivers nothing to the lungs and spends the minutes you need to find the actual problem.

Decreased systemic vascular resistance from alveolar recruitment: A drop in systemic vascular resistance is the mechanism behind every form of distributive shock, sepsis, anaphylaxis, and neurogenic shock, and you would expect warm skin and a wide pulse pressure to go with it. Recruiting alveoli does not dilate the systemic vascular bed, and if anything relieving hypoxemia and hypercarbia lowers pulmonary vascular tone rather than systemic tone. The key wins on timing and mechanism together: a pressure that falls within two minutes of turning a dial is a mechanical consequence of that dial, not a new vasodilatory disease.

Increased venous return from decreased intrathoracic pressure: a real and correct piece of physiology, it just describes a spontaneous breath, where the chest generates negative pressure and actively pulls blood back to the right heart. Positive end-expiratory pressure does the opposite by definition, holding pressure positive even at the end of exhalation. It also fails on direction: more venous return would raise the blood pressure, and this patient's fell.

Increased left ventricular afterload from alveolar recruitment: Increased left ventricular afterload is the right explanation for hypotension caused by a heart ejecting against a high resistance, as in a hypertensive crisis or severe aortic stenosis, and it is a left-sided problem. Positive intrathoracic pressure runs the other way, lowering the wall stress the left ventricle ejects against, which is one of the reasons CPAP helps in acute pulmonary edema. The key names the correct chamber and direction: chest pressure hurts the filling side first, because the great veins that fill the right heart are upstream and thin-walled.

Increase the ventilation rate: A faster rate is the correct move when the end-tidal carbon dioxide is high in a patient with clear lungs, which is a ventilation problem. This patient's carbon dioxide is 36 with a rectangular waveform, which is normal, so raising the rate would drive it below normal and shorten expiratory time for no benefit. Both settings change something about the breath, but the key moves the oxygenation control and this one moves the carbon dioxide control, and only the oxygenation number is abnormal.

Increase the tidal volume: A larger tidal volume is right when the chest rise is shallow, the volume is set below the lung-protective range, or the patient is retaining carbon dioxide. The chest rises with each delivered breath here and the carbon dioxide is already normal, so the extra volume buys nothing and adds tidal stretch to alveoli that are already open. The key recruits the alveoli that are closed without stretching the ones that are not, which is the whole reason end-expiratory pressure rather than volume is the oxygenation lever.

Decrease the inspiratory time: Shortening the inspiratory time is a real correction when air trapping is the problem, because a shorter inspiratory time leaves more of the cycle for exhalation, and that belongs to obstructive disease. Nothing here suggests obstruction: breath sounds are equal, the capnography waveform is rectangular rather than showing the sloped upstroke of obstruction, and no rising pressures are described. It also works directly against the goal, since less time in inspiration means less time holding alveoli open, and this patient needs more of that, not less.

Increase the CPAP setting: Turning the pressure up is the right adjustment for a patient who is still breathing adequately but whose work of breathing and oxygenation have only partly improved, where more pressure recruits more alveoli and offloads more of the effort. That only works while the patient has a drive to assist, and this patient is difficult to arouse at a rate of 8 with a carbon dioxide of 68. The device cannot deliver a breath the patient does not take, so raising the number changes the pressure but not the number of breaths, while the key supplies the breaths themselves.

Administer nebulized albuterol through the circuit: A nebulized beta agonist is the answer to bronchospasm, where you would hear wheezing with a prolonged expiratory phase in an asthma or chronic obstructive pulmonary disease exacerbation, and it can be run through a CPAP circuit. This patient's problem is decompensated heart failure with a failing respiratory drive, and a bronchodilator does not raise a rate of 8. It also costs something, since the tachycardia it produces is unwelcome at a pulse of 108 with a blood pressure of 96/60, and the key addresses the actual deficit, which is minute ventilation.

Continue the current therapy and reassess in 5 minutes: Continuing and reassessing is correct when a patient on CPAP is trending the right way, with easing work of breathing, a stable or falling carbon dioxide, and a clearing mental status, because the therapy just needs time to work. Every trend in this question runs the other direction, and a rising carbon dioxide with a falling level of consciousness is the definition of noninvasive ventilation failing. The key acts inside the window where the transition is controlled, while this choice waits until the patient arrests and the airway has to be taken under the worst conditions.

Pressure support ventilation: the mode for a patient who is breathing on their own but tiring, augmenting each patient-triggered breath with a set inspiratory pressure to unload the work of breathing, and it is the mode used for a weaning trial. It has no set rate of its own, so it delivers exactly nothing to a patient with no inspiratory effort. This patient is chemically paralyzed, so the one thing the mode requires to function is the one thing that has been deliberately removed, and the patient would sit apneic until a backup alarm and rate intervened.

CPAP: holds a single pressure across the entire respiratory cycle, splinting alveoli open, and it is the right tool for a spontaneously breathing patient who needs recruitment and oxygenation support. It delivers no breaths, no rate, and no tidal volume. Applying it to a paralyzed patient means oxygen is being held in the lungs while no gas is actually being exchanged in or out, so the carbon dioxide climbs steadily even while the saturation looks acceptable.

Bilevel positive airway pressure: continuous pressure with a higher pressure added during inspiration, and it is indicated for a spontaneously breathing patient who needs help with ventilation as well as oxygenation, such as a COPD exacerbation retaining carbon dioxide. The mode is built around sensing the patient's own inspiratory effort, and it is a noninvasive support strategy rather than the controlled invasive mode you select for a freshly intubated patient with a secured tube and zero drive. Assist-control's guarantee of both rate and volume is precisely what a paralyzed patient needs and what a support mode cannot promise.

Perform bilateral needle decompression of the chest: Needle decompression is the treatment for a tension pneumothorax, which raises airway pressures the same way by squeezing the lung from outside, and it comes with diminished or absent breath sounds on the affected side, a trachea deviated away, distended neck veins, and hypotension. This question deliberately hands you the negatives: breath sounds equal and clear, trachea midline, and a blood pressure of 108/64 in a post-arrest patient. Both conditions compress the lung from outside, but the question locates that compression below the diaphragm with a distended, tympanic abdomen, and needling a chest that is not tense creates two iatrogenic pneumothoraces in a patient who just regained a pulse.

Increase the positive end-expiratory pressure: More positive end-expiratory pressure is the right response to hypoxemia from alveolar collapse in a lung whose compliance is otherwise workable. This lung is being squeezed from outside with a plateau pressure already at 36, so adding pressure raises every number in the circuit, increases the barotrauma risk, and drops venous return in a patient whose pressure is only 108/64 minutes after return of spontaneous circulation. The key lowers those same pressures by removing what is pressing on the diaphragm rather than pushing harder against it.

Withdraw the endotracheal tube 2 cm: Withdrawing the tube treats a right mainstem intubation, which also raises airway pressures because the full tidal volume is being driven into one lung. The clinching finding for that is unequal breath sounds, and this patient's are equal and clear bilaterally, so the tube depth is not the problem. The key follows the finding the question actually gives you, a markedly distended and tympanic abdomen after 15 minutes of BVM ventilation, while pulling back a correctly placed tube risks extubating a post-arrest patient for nothing.

Titrate it to keep the SpO₂ 88% to 92%: A target of 88 to 92 percent belongs to a different patient entirely, the chronic carbon dioxide retainer, typically advanced COPD, where excessive oxygen worsens ventilation-perfusion matching and can blunt respiratory drive. Nothing in this question describes chronic lung disease. This is a brain and a myocardium that were just globally ischemic and are now reperfusing, and deliberately running them at 88 to 92 percent adds a hypoxic insult on top of the ischemic one they already took.

Continue it at 1.0 for the rest of transport: A fraction of inspired oxygen of 1.0 is exactly correct during the arrest, which is why it is already set there, since oxygen delivery is limited by the flow compressions generate and the saturation cannot be measured reliably. Circulation has now returned and the oximeter is trustworthy at 100 percent, so the justification for the setting has expired. Continuing it delivers hyperoxia with zero additional oxygen carried, since saturated hemoglobin cannot hold more, while adding free radical injury to the two organs that matter most.

Discontinue it and ventilate with room air: Room air is the correct starting gas for a newborn resuscitation and for plenty of spontaneously breathing patients whose saturations are normal. Removing supplemental oxygen entirely from a post-arrest patient gives up the ability to titrate at all and risks a desaturation that a freshly reperfused brain tolerates very poorly. The instruction is to come down to a normal target and hold it there, not to withdraw oxygen and watch what happens.

CPAP at 5 cmH2O: A low setting is still positive pressure applied across the pleural defect on every breath. There is no pressure below which CPAP becomes safe in a known pneumothorax; a lower number only slows the rate at which the pleural air accumulates.

CPAP at 10 cmH2O: A higher setting drives pleural air accumulation faster, so tension physiology develops sooner. The oxygenation benefit does not offset converting a stable injury into an immediately life-threatening one.

Bilevel noninvasive ventilation: Bilevel ventilation applies positive pressure throughout the respiratory cycle and uses inspiratory pressures higher than CPAP, so it carries the same risk to a greater degree.