Question 1

Which of the following is false about flow triggering of spontaneous breaths during mechanical ventilation?

Accepted Answer

Flow triggering does not specifically reduce the work of breathing due to small endotracheal tubes. It may however be advantageous in patients with small endotracheal tubes due to the minimal or absent resistance of the circuit in flow triggering as compared to pressure or time triggering. The rest of the options are true about flow triggering.

Question 2

To prevent atelectasis and improve gas exchange, most thoracic surgery patients placed on ventilatory support receive which of the following?

Accepted Answer

5 cm H2O Positive End-Expiratory Pressure (PEEP) is commonly used in ventilatory support for thoracic surgery patients to prevent atelectasis and improve gas exchange by keeping the airways open during expiration.

Question 3

In which of the following conditions is PEEP NOT likely to be useful?

Accepted Answer

PEEP may not be useful in patients with neuromuscular diseases as they may not be able to tolerate the increased work of breathing that is associated with PEEP. Additionally, neuromuscular diseases may affect the patient's ability to cough and clear secretions, thus increasing the risk of potential complications with PEEP use. However, PEEP can be useful in patients with ARDS, pulmonary edema, and acute lung injury as it helps to maintain alveolar recruitment and improve oxygenation.

Question 4

Which of the following inspiratory flow patterns would result in the lowest peak inspiratory pressure?

Accepted Answer

A decelerating flow pattern would result in the lowest peak inspiratory pressure as it starts with a high flow rate and decreases gradually towards the end of inspiration, allowing sufficient time for the alveoli to fully expand and reducing the risk of over-inflation. This pattern also mimics normal breathing mechanics, where inspiratory flows in healthy individuals start high and decrease towards the end of inspiration. Accelerating, square, and constant flow patterns may increase the risk of barotrauma or lung injury as they deliver a higher flow rate at the beginning of inspiration.

Question 5

In which of the following clinical situations is the incidence of auto-PEEP the greatest?
I.patients with high respiratory rates
II.intubated patients with obstructive lung disease
III.patients with low minute volumes

Accepted Answer

Auto-PEEP (positive end-expiratory pressure) is most commonly seen in patients with high respiratory rates and in intubated patients with obstructive lung disease. High respiratory rates can prevent full exhalation, leading to air trapping and auto-PEEP. Obstructive lung disease, such as COPD, inherently causes airflow limitation and air trapping. Low minute volumes do not typically contribute to the development of auto-PEEP.

Question 6

On some ventilators, what can a trigger setting that is too sensitive cause?

Accepted Answer

A trigger setting that is too sensitive can cause auto-cycling, where the ventilator delivers breaths even when the patient is trying to breathe on their own.

Question 7

For adults with otherwise normal lungs who are receiving ventilatory support in the continuous mandatory ventilation control or assist-control mode, inspiratory flow should be set to provide what I:E?

Accepted Answer

The correct inspiratory to expiratory (I:E) ratio for adults with otherwise normal lungs receiving ventilatory support in the continuous mandatory ventilation control or assist-control mode is typically set to 1:2. This ratio allows for adequate time for exhalation, preventing air trapping, barotrauma, or auto-PEEP (positive end-expiratory pressure), which can occur if the exhalation time is too short.

Question 8

When adjusting the FIO₂ setting for a patient receiving mechanical ventilatory support, what should your goal be?

Accepted Answer

The goal is to minimize oxygen toxicity risk by reducing FIO2 to below 0.50 as soon as the patient's oxygenation status allows.

Question 9

Which of the following ventilator adjustments would NOT decrease inspiratory time?

Accepted Answer

Increasing the tidal volume would actually increase inspiratory time, as it requires more time to deliver a larger volume of air.

Question 10

Immediately after cardiac arrest and resuscitation, a patient is placed on a ventilator in the continuous mandatory ventilation assist-control mode. What initial FIO₂ would you recommend?

Accepted Answer

After cardiac arrest and resuscitation, it's common to start with a high fraction of inspired oxygen (FiO2) to ensure adequate oxygenation. An initial FiO2 of 1.0 (100% oxygen) is often recommended to quickly correct any hypoxemia, after which it can be titrated down based on blood gas results and oxygen saturation.

Question 11

Which of the following trigger levels is appropriate when setting a ventilator for flow-triggering?

Accepted Answer

Flow-triggering on a ventilator is typically set at a sensitivity level where a small decrease in flow (indicating the patient's effort to inhale) triggers the ventilator to deliver a breath. A setting of 1 to 3 L/min below baseline flow is appropriate because it is sensitive enough to detect the patient's inspiratory effort without being so sensitive that it triggers on accidental fluctuations or too insensitive to detect the effort.

Question 12

Which of the following criteria represents the recommended starting point for considering the use of PEEP?

Accepted Answer

The recommended starting point for considering the use of PEEP is a PaO2 < 60 mmHg on an FiO2 > 0.40-0.50. Option B is the only choice that meets this criteria.

Question 13

A chronic obstructive pulmonary disease (COPD) patient receiving ventilatory support in the CMV assist-control mode at a rate of 14 and a V_T of 750 ml exhibits clinical signs of air-trapping. Which of the following would you recommend to correct this problem? I. Decrease “E” time. II. Increase the inspiratory flow rate. III. Decrease the assist-control rate.

Accepted Answer

Increasing the inspiratory flow rate and decreasing the assist-control rate can help reduce air-trapping by allowing more time for exhalation.

Question 14

Which of the following is FALSE about flow-triggered ventilatory support?

Accepted Answer

Flow-triggering may increase the work of breathing in patients with small endotracheal tubes and auto-PEEP due to increased resistance of the small diameter tube.

Question 15

An adult patient in respiratory failure has the following blood gases on a nasal cannula at 5 L/min: pH = 7.20; PaCO₂ = 67 mm Hg; HCO₃^- = 27 mEq/L; PaO₂ = 89 mm Hg. The attending physician orders intubation and ventilatory support. What FIO₂ would you recommend to start with?

Accepted Answer

The answer of An adult patient in respiratory failure has...

Question 16

What flow pattern is least optimal for ventilating a patient with cardiovascular instability?

Accepted Answer

Decelerating flow pattern is the least optimal for ventilating a patient with cardiovascular instability. This flow pattern leads to an increase in intra-thoracic pressure during inspiration which can decrease venous return and cause a decrease in cardiac output. It is important to maintain a constant flow pattern or an accelerating flow pattern to prevent these negative effects.

Question 17

Beneficial effects of using high inspiratory flows in patients with chronic airflow obstruction receiving flow-limited mechanical ventilation include which of the following?
I.decreased work of breathing
II.improved gas exchange
III.decreased auto-PEEP

Accepted Answer

High inspiratory flows can help decrease the work of breathing by providing an adequate tidal volume during inspiration. This can also improve gas exchange by increasing alveolar ventilation. Additionally, it can help decrease auto-PEEP by flushing out trapped air in the lungs. Therefore, all three options are correct.

Question 18

Which of the following statements is NOT true regarding the use of an inspiratory pause during mechanical ventilation?

Accepted Answer

An inspiratory pause has not been shown to increase the effectiveness of bronchodilator therapy. It is commonly used to optimize mechanical ventilation in patients with ARDS by improving oxygenation and recruitment of collapsed alveoli. It can also be helpful when obtaining a chest radiograph by allowing for better visualization of lung fields. Additionally, an inspiratory pause will increase mean airway pressure which can improve gas exchange and oxygenation.

Question 19

Which of the following trigger levels is appropriate when setting a ventilator for pressure-triggering?

Accepted Answer

When using pressure-triggering, the trigger level should be set below the baseline pressure, typically 0.5 to 1.5 cm H2O below. This allows for a small decrease in pressure to act as a trigger for the ventilator to begin delivering a breath. Setting the trigger level too high can result in inadequate ventilation or patient discomfort. Therefore, the appropriate choice is C (0.5 to 1.5 cm H2O below the baseline pressure).

Question 20

When starting flow-limited ventilatory support on an adult patient, which of the following inspiratory flow settings would you initially select?

Accepted Answer

A flow rate of 60 L/min is typically selected as the initial setting for adult patients receiving flow-limited ventilatory support to ensure adequate gas exchange and patient comfort.

Quiz 44: Initiating and Adjusting Ventilatory Support