Invasive and Mechanical Ventilation Principles

What is the definition of a Level 3 Adult Critical Care Unit?

A specifically staffed and equipped hospital area for patients with potentially reversible and life-threatening conditions.

List three primary indications for initiating invasive ventilation.

• Inadequate oxygenation

• Inadequate ventilation

• Impaired ability to protect the airway.

Invasive ventilation may be used as a short-term measure when a patient requires a general anaesthetic for what purpose?

Surgical procedures.

What are the two main types of artificial airways used for invasive ventilation?

Endotracheal tube and Tracheostomy.

What are the primary goals of invasive ventilation regarding gas exchange and patient effort?

To improve oxygenation/ventilation and to reduce the work of breathing.

A key goal of invasive ventilation is to avoid high peak pressures. What does 'peak pressure' refer to?

The highest pressure reached during the inspiratory phase of the respiratory cycle.

Define 'volutrauma' as a complication of mechanical ventilation.

Lung injury caused by overdistension of the alveoli, which can lead to conditions like pneumothorax and acute lung injury.

What are two examples of lung injury that can result from volutrauma?

Pneumothorax and acute lung injury.

Oxygen toxicity during ventilation is proportional to the duration of exposure to a fraction of inspired oxygen (FiO₂) greater than what value?

An FiO₂ greater than 0.6.

How can positive pressure ventilation affect a patient's cardiac output?

It may be increased or decreased.

What does the abbreviation VAP stand for in the context of ventilation complications?

Ventilator Associated Pneumonia.

List three measures that can help reduce the risk of ventilator-associated pneumonia (VAP).

• Hand washing

• Elevation of the head of the bed

• Proper nutrition.

What practice concerning medication helps decrease the risk of VAP with a resistant pathogen?

The avoidance of unnecessary antibiotics.

Name three potential complications arising specifically from the use of an endotracheal tube.

Laryngeal dysfunction, tracheal stenosis, and tracheomalacia (others: hard/soft palate injuries, obstruction).

In _____ controlled ventilation, an inspiratory pressure limit is set for each breath, and the tidal volume achieved is variable.

pressure

In _____ controlled ventilation, a set tidal volume is supplied by the ventilator, and the inspiratory pressure is the resulting variable.

volume

In pressure-controlled ventilation (PCV), what two factors determine the tidal volume achieved with each breath?

The set pressure in the airways and the patient's lung compliance.

What does the abbreviation BIPAP ASB stand for?

Biphasic Positive Airway Pressure with Assisted Spontaneous Breathing.

In BIPAP ASB mode, the ventilator cycles between an upper and lower pressure, and the patient can trigger their own breaths which are then _____ by the ventilator.

supported

What is a major advantage of BIPAP ASB regarding patient sedation?

It allows for a reduced need for heavy sedation.

What is a significant disadvantage of BIPAP ASB related to tidal volume?

The tidal volume is uncontrolled and variable, which creates a risk of volutrauma.

What condition can occur in a patient on BIPAP ASB if the pressure support level is set too low?

Respiratory fatigue.

What does the abbreviation CPAP ASB stand for?

Positive Airway Pressure with Assisted Spontaneous Breathing.

What is the primary clinical use for CPAP ASB mode?

It is used to wean patients from BIPAP ASB.

In CPAP ASB mode, ventilation relies solely on _____ as there is no set inspiratory pressure.

the PEEP (Positive End Expiratory Pressure)

In volume-controlled ventilation (VCV), what two values are directly controlled by the clinician?

The tidal volume and the number of mandatory breaths per minute.

In volume-controlled ventilation, the tidal volume multiplied by the respiratory rate results in the _____

minute volume (MV)

What does SIMV stand for in mechanical ventilation?

Synchronized Intermittent Mandatory Ventilation.

In SIMV mode, how are patient-initiated breaths treated if they are over the set minimal rate?

No additional support is given for those breaths.

Why is SIMV less frequently used as an initial ventilator mode?

It is usually associated with a greater work of breathing for the patient.

In which basic mode of ventilation does the patient make no spontaneous inspiratory effort?

Mandatory mode.

In which basic mode of ventilation does the patient make some, but not all, of the inspiratory effort?

Assisted mode.

In which basic mode of ventilation are breaths triggered and determined fully by the patient, with support given to achieve them?

Spontaneous mode.

Volume-Control / CMV is an example of which basic mode of ventilation?

Mandatory mode.

BIPAP-ASB is an example of which basic mode of ventilation?

Assisted mode.

Pressure Support (ASB) is an example of which basic mode of ventilation?

Spontaneous mode.

What is Positive End Expiratory Pressure (PEEP)?

The application of positive pressure at the end of expiration to prevent alveolar collapse.

What is the primary purpose of applying PEEP during ventilation?

It splints the alveoli open, improving oxygenation by recruiting collapsed alveolar units and increasing FRC.

What is Pressure Support (PS) in the context of mechanical ventilation?

A small amount of pressure applied during spontaneous inspiration to help the patient overcome the resistance of an artificial airway.

What is the definition of Fraction of Inspired Oxygen (FiO₂)?

The proportion of oxygen in the air that is inspired, expressed as a fraction.

What is the FiO₂ of normal room air?

0.21

Define Respiratory Rate (RR) on a ventilator.

The number of mandatory or spontaneous breaths either taken by the patient or delivered by the ventilator per minute.

What is Tidal Volume (VT)?

The amount of gas, measured in millilitres, inhaled or exhaled from a person's lungs with every breath.

How is Minute Volume (MV) calculated?

It is calculated by multiplying Tidal Volume (VT) by Respiratory Rate (RR).

What is Peak Airway Pressure (PAP) and what is its maximum recommended limit?

The highest pressure generated in the lungs during inhalation; it should not exceed 30 cmH₂O.

What does End Tidal CO₂ (ETCO₂) monitoring measure?

The non-invasive measurement of the partial pressure of exhaled carbon dioxide.

What does Peak Plateau Pressure (Pplat) reflect, and what is its maximum limit?

It reflects the pressure the alveoli are exposed to after inspiration has finished and should not exceed 30 cmH₂O.

List two adverse consequences of using an unnecessarily high FiO₂.

Absorption atelectasis and airway/parenchymal injury (also accentuation of hypercapnia).

What is the typical starting range for the set respiratory rate (f) on a ventilator?

10-15 breaths per minute.

On a ventilator display, what does 'ftotal' represent?

The total number of breaths per minute, which is the sum of mandatory (fmand) and spontaneous (fspont) breaths.

What is the target range for tidal volume (Vt), expressed in ml per kg of body weight?

6-8 ml/kg.

What is the typical range for PEEP settings, measured in cmH₂O?

From +2 to +20 cmH₂O.

What are two potential negative effects of using high levels of PEEP?

It can cause barotrauma and can depress cardiac output through reduced venous return.

What is the typical range for Inspiratory Pressure (Pinsp) settings, measured in cmH₂O?

+5 to +40 cmH₂O.

List the key components that should be documented for a patient on invasive ventilation.

Mode, delivery system, pressures, oxygen requirement (FiO₂), total rate, tidal volume, and saturation (SaO₂).

What is the first thing you should do when a ventilator alarm sounds?

Check the patient's monitors to ensure they have adequate oxygenation.

If a ventilator alarm sounds, the patient is deteriorating, and the problem cannot be immediately identified, what is the correct emergency procedure?

Disconnect the patient from the ventilator, use a manual resuscitation bag, and call for help.

Name three common patient-related factors that can trigger a ventilator alarm.

Coughing, biting the tube, or having secretions in the airway.

What is a potential cause for a ventilator alarm related to the breathing circuit?

An air leak or a disconnection from the patient.