Exam 45: Mechanical Ventilators

In which of the following situations is pressure-controlled ventilation sometimes used? 1) When a precise PaCO₂ has to be maintained (some closed-head injuries) 2) When more even distribution of ventilation is required 3) When ventilating patients with severe, refractory hypoxemia 4) When tidal volume in unstable due to leaks

Which of the following are characteristics of a ventilator that function as a true volume controller? 1) Its pressure waveform changes with changes in lung mechanics. 2) It measures and uses volume to control the volume waveform. 3) Its volume waveform stays constant with changes in lung mechanics.

If a patient initiates a ventilator breath, the trigger variable could be which of the following? 1) Pressure 2) Flow 3) Time 4) Volume

A patient receiving continuous mandatory ventilation in the control mode has an inspiratory time of 1.5 sec and an expiratory time of 2.5 sec. What is the frequency of breathing?

During volume-targeted ventilation, which of the following settings determine the machine-delivered minute volume? 1) Volume 2) Flow 3) Rate

In which of the following modes inspiration ends when flow decays to some preset value?

During mechanical ventilation, what variable causes a breath to end?

During volume-targeted ventilation, which of the following settings determine the inspiratory time? 1) Volume 2) Flow 3) Rate

During mechanical ventilation, a spontaneous breath is defined as one that:

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 12/min. The inspiratory time control is set at 33%. What is the expiratory time?

How would a ventilatory support device that uses pressure regulators, needle valves, and balloon valves to regulate most or all of the parameters of ventilation be classified?

If the pressure waveform of a ventilator remains the same when a patient's lung mechanics change, then what is the ventilator?

A ventilator's pressure waveform changes when a patient's lung mechanics change, but its volume waveform remains the same. The device does not directly control the delivered volume. What is this ventilator?

What is the primary physiological effect of positive end expiratory pressure (PEEP)?

Which of the following parameters can serve as the cycle variable during ventilatory support? 1) Volume 2) Pressure 3) Flow 4) Time

A volume-cycled ventilator has a rate knob for setting the controlled frequency of breathing. If this control is set to 12/min, which of the following other settings will determine the inspiratory and expiratory times? 1) FiO₂ 2) Flow 3) Volume

A time-cycled constant flow generator is set up with a flow of 35 L/min and an inspiratory time of 1.7 sec. What is the approximate V_T?

Which of the following modes is a good example of adaptive control?

While observing a patient receiving ventilatory support, you notice that some delivered breaths are begun or ended by the machine, whereas others are begun and ended by the patient. Which of the following modes of ventilatory support is in force?

During mechanical ventilation, a mandatory breath is defined as one that is: