10 free Paramedic practice questions: Ventilator Management and Advanced Oxygenation

The average of the measured weight and the predicted weight for this height: Averaging the two weights looks like a fair middle ground. The 140 kilograms still pushes the result too high. Half of an inflated number is still too big for a chest built at 5 feet 6 inches. Ideal body weight is not a blend, and lung size follows ideal body weight alone.

The adjusted weight used for medication dosing in a large patient: Adjusted body weight is a real tool for dosing some medications in obese patients. Adjusted body weight blends lean weight with part of the extra fat, because some drugs spread into fat. Tidal volume has nothing to do with how a drug spreads through tissue. Tidal volume follows the size of the alveoli, which height and sex set.

The measured weight of 140 kilograms, which reflects the current oxygen demand: A patient who weighs 140 kilograms does use more oxygen. The ventilator volume for a 5 foot 6 inch chest is set by how much lung there is to stretch. You meet a higher oxygen demand with FiO2 and PEEP, not by inflating the alveoli past the size that height and sex predict.

Replace the flow sensor, which is counting breaths that were not delivered: The EtCO2 fell from 38 to 24, which proves the extra breaths are being delivered, so the sensor is counting correctly. A new sensor leaves the water in place, and the autotriggering keeps going.

Deepen the sedation to stop the patient from triggering extra breaths: Eight minutes after rocuronium, this patient is still paralyzed and cannot make any effort to trigger the ventilator. No amount of sedation affects the water moving in the tubing, and the water is what fires each breath.

Redose the paralytic to suppress the breakthrough respiratory effort: Rocuronium given eight minutes ago is still fully working, so there is no breakthrough effort to suppress. More paralytic does nothing to the pooled water in the dependent loop, and that water is the real trigger.

Serial blood pressure measurement at three-minute intervals during sedation: Blood pressure checks are part of standard sedation monitoring. This child's problem is the shallow, slow breathing, not the blood pressure. Blood pressure changes from hypoventilation show up only after the carbon dioxide has already climbed. Serial pressures miss the early window that capnography catches.

Repeat pulse oximetry readings every two minutes throughout the procedure: Pulse oximetry is already running, and checking it more often sounds like closer watching. On high-flow oxygen, the SpO2 stays at 100% even while this child breathes shallow and slow. A reading every two minutes still misses the rising carbon dioxide. Pulse oximetry tells you about oxygen, and this child's problem is ventilation.

Continuous cardiac monitoring with attention to the development of bradycardia: Bradycardia is a real late warning sign of hypoxia in children, and cardiac monitoring belongs in every sedation. This child's heart rate has not dropped yet. The shallow, slow breathing and being hard to wake come first. Waiting for bradycardia means waiting until the child's reserve is already gone.

Reconnect the ventilator and increase the respiratory rate: With absent breath sounds on the left and JVD, more breaths at a faster rate push more air into the trapped pleural space. The tension gets worse faster.

Administer a second fluid bolus and reassess in ten minutes: The neck veins are distended, which points to obstructive shock from trapped air, not hypovolemic shock with flat neck veins. Fluid does not let the air out, and a second bolus only delays the needle decompression.

Reduce the set PEEP and continue transport, reassessing every five minutes: The blood pressure did not improve with the circuit open, so the disconnection already ruled out auto-PEEP. Changing the PEEP does nothing for a tension pneumothorax.

Begin chest compressions immediately: A sudden loss of the waveform to zero can be a sign of cardiac arrest. In a patient without a confirmed pulse, you would check for one right away. This patient has a strong carotid pulse. Compressions on a patient with a pulse are not harmless. Compressions also treat a circulation problem this patient does not have, while a displaced tube goes unfixed.

Replace the sensor and continue transport: Equipment failure can cause a flat capnography line. A disconnected sampling line, a sensor fouled by moisture or secretions, or a loose cable can all do it. Blaming the sensor first is still the most dangerous assumption. 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 sensor that is really broken will still be broken thirty seconds later.

Increase the ventilation rate and reassess: Changing the ventilation rate is how you fix a value trending the wrong way, like a rising EtCO2 from hypoventilation. A rate change assumes gas is still moving through the tube, and a reading of zero tells you gas is not moving. Bagging faster through a displaced, blocked, or disconnected tube delivers nothing to the lungs. The faster rate uses up the minutes you need to find the real problem.

Increase the CPAP setting: CPAP pressure only helps on breaths the patient takes, and this patient is hard to arouse, breathing 8 times a minute, with an EtCO₂ of 68. More pressure opens more alveoli, but a higher setting does not add a single breath.

Administer nebulized albuterol through the circuit: Albuterol treats bronchospasm, and this patient has heart failure and is not breathing enough. Albuterol can be run through a CPAP circuit, but it does not raise a respiratory rate of 8. Albuterol also speeds up the heart, and this patient already has a pulse of 108 and a blood pressure of 96/60.

Continue the current therapy and reassess in 5 minutes: Every trend in this patient is going the wrong way. The EtCO₂ rose from 45 to 68, the respirations are 8 and shallow, and the patient is difficult to arouse. A rising EtCO₂ with a falling level of consciousness means CPAP is failing. Waiting 5 minutes risks a respiratory arrest, and then you have to take the airway under the worst conditions.

Pressure support ventilation: Pressure support is for a patient who is breathing on their own but getting tired. Pressure support adds pressure to each breath the patient starts, and it is the mode used for a weaning trial. Pressure support has no set rate of its own. A paralyzed patient starts no breaths, so pressure support gives this patient nothing. This patient would sit apneic until the backup alarm and rate took over.

CPAP: holds one steady pressure through the whole breathing cycle and keeps the alveoli open. CPAP is for a patient who is breathing on their own and needs help with oxygenation. CPAP gives no breaths, no rate, and no tidal volume. On a paralyzed patient, no gas moves in or out, and the carbon dioxide keeps climbing while the saturation looks fine.

Bilevel positive airway pressure: adds a higher pressure when the patient breathes in. Bilevel is for a patient who is breathing on their own and needs help moving air, like a COPD patient holding on to carbon dioxide. Bilevel is built around sensing the patient's own breaths. Bilevel is also a noninvasive mode, not the controlled mode you use for a freshly intubated patient with no drive to breathe.

Increase the fraction of inspired oxygen: The SpO₂ is 98% on a fraction of inspired oxygen of only 0.40, so there is no low oxygen to fix. Added oxygen also does not remove any carbon dioxide. The number that is off is the EtCO₂ of 62, and the rate is the setting that controls the EtCO₂.

Increase the positive end-expiratory pressure: The lungs are clear, the peak inspiratory pressure is 18, and the saturation is 98%, so there are no collapsed alveoli to open. PEEP is for low oxygen that will not come up on a high oxygen concentration because blood is flowing past collapsed alveoli. Extra PEEP would mostly raise the pressure in the chest and could drop the blood pressure. Like option B, PEEP works on oxygenation, and oxygenation is already fine.

Decrease the tidal volume: A smaller tidal volume moves the wrong way. Less volume means less minute ventilation, and the EtCO₂ of 62 climbs even higher. This volume is already a lung protective 6 mL/kg with a peak pressure of 18, so the lung is not being overstretched. Raising the rate increases minute ventilation and keeps the lung protection.

Titrate it to keep the SpO₂ 88% to 92%: A target of 88% to 92% is for a COPD patient who retains carbon dioxide, when you do not know the patient's normal baseline. Nothing in this question describes lung disease. This patient's brain and heart just went without oxygen during the arrest. Holding the SpO₂ that low leaves organs that are already injured short on oxygen again.

Continue it at 1.0 for the rest of transport: An FiO₂ of 1.0 is right during the arrest itself. During CPR, the pulse oximeter cannot give a reliable reading, so you use the most oxygen you have. Circulation is back now, and the SpO₂ has read 100% for 5 minutes. The hemoglobin is already full. More oxygen adds nothing the blood can carry, and it adds more free radical injury.

Discontinue it and ventilate with room air: Ventilating on room air is how you start resuscitating a term newborn. This patient is an adult who is unresponsive and just came out of cardiac arrest. Taking the oxygen away can drop the SpO₂ below the target. The goal is the lowest amount of oxygen that holds the SpO₂ at 94% to 98%, not shutting the oxygen off.

CPAP at 5 cmH2O: a low setting, and a low setting sounds safer. A low setting is still positive pressure pushing air through the hole in the lung on every breath. No CPAP pressure is safe in a known pneumothorax. A lower number only slows how fast the air builds up in the chest.

CPAP at 10 cmH2O: pushes air into the chest faster than a low setting does, so a tension pneumothorax develops sooner. Better oxygenation is not worth turning a stable injury into one that can kill the patient right away.

Bilevel noninvasive ventilation: applies positive pressure through the whole breath. The pressure on inhalation is higher than with CPAP. Bilevel carries the same risk as CPAP, only worse.