7 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.

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.

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: Turning up the CPAP pressure helps a patient who is still breathing well but has only partly improved. More pressure opens more alveoli and takes over more of the work of breathing. CPAP pressure only helps on breaths the patient takes. This patient is hard to arouse, breathing 8 times a minute, with an EtCO₂ of 68. A higher setting raises the pressure, but a higher setting does not add a single breath.

Administer nebulized albuterol through the circuit: Nebulized albuterol treats bronchospasm. With bronchospasm you hear wheezing and a long expiratory phase, like in an asthma or COPD flare. Albuterol can be run through a CPAP circuit. This patient has heart failure and is not breathing enough. Albuterol 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: Continuing and reassessing is right when a patient on CPAP is getting better. The work of breathing eases, the EtCO₂ holds steady or falls, and the patient becomes more alert. Every trend in this patient is going the other way. 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.

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.