classification of ventilator modes

What are the four criteria of ventilator mode classification?

Control Variable, Breath Sequence, Phase Variables, Targeting Scheme.

What does CMV stand for in ventilation terminology?

Continuous Mandatory Ventilation.

What is the main purpose of mechanical ventilation?

To ensure that the patient receives a minute volume which satisfies their respiratory needs.

How does Chatburn's classification simplify control variables?

It simplifies it to two control variables: Pressure and Volume.

What is the difference between mandatory breaths and spontaneous breaths?

Mandatory breaths are delivered by the ventilator, whereas spontaneous breaths are initiated by the patient.

What are the three possible breath sequences in ventilation?

Continuous Mandatory Ventilation (CMV), Intermittent Mandatory Ventilation (IMV), Continuous Spontaneous Ventilation (CSV).

What does the term 'breath sequence' refer to?

It involves identifying the type of breaths possible within the mode.

What is the targeting scheme in mechanical ventilation?

It is how the ventilator controls a variable such as flow, pressure, or volume.

What kind of control do old style ventilators use?

Open Loop Control.

How has the control in current ICU ventilators evolved?

They use Closed Loop Control.

What is a set point targeting scheme?

The ventilator adjusts its output to maintain a preset input variable such as flow or pressure.

What is a dual targeting scheme in ventilation?

The ventilator can decide whether a breath will be either pressure or volume controlled.

How does servo-controlled ventilation work?

The ventilator monitors input information from the patient and adjusts the output accordingly.

What distinguishes adaptive targeting schemes in ventilation?

The ventilator automatically adjusts a set point to maintain a different operator-selected set point.

What are phase variables in ventilator modes?

They include cycling variable and trigger variable.

What control variable does CMV use?

It can be either volume or pressure.

What does the term 'mandatory breaths' indicate in CMV?

Breaths that are delivered automatically by the ventilator.

What is the primary characteristic of a Vol CMV mode?

Minimum work is required from the patient due to full ventilatory support.

What is the significance of the set rate in Vol CMV?

It acts as a backup rate in case of patient apnea.

How are pressure or volume controlled in a Vol CMV mode?

The ventilator will determine the pressure or volume while allowing the patient to time the breaths.

What are the two types of CMV?

VC-CMV (Volume Control CMV) and PC-CMV (Pressure Control CMV).

How does VC-CMV control variable operate?

It primarily controls volume and can utilize either a square or decreasing flow waveform.

What characteristics define the phase variables of VC-CMV?

Time cycled, time triggered, or patient triggered mandatory breaths.

What happens to flow, volume, and time in VC-CMV?

They remain constant despite changes in patient lung compliance or resistance.

What does the targeting scheme set point indicate in VC-CMV?

The control variable is volume, and the targeting is flow.

What parameters need to be set in VC-CMV?

Flowrate and pattern of flow, tidal volume, minimum respiratory rate, PEEP, FiO2, and sensitivity for patient-triggered breaths.

What applications of VC-CMV are suitable for patients?

It’s used when guaranteed volumes are required and changes in lung characteristics are not expected.

What happens to respiratory rate and minute volume when patients trigger breaths in VC-CMV?

They will increase as patient-triggered breaths occur.

What kind of flow pattern is expected in the VC-CMV waveforms?

A decreasing flow pattern.

What is the breathing support provided by CMV?

Full ventilatory support, requiring the least amount of work from the patient.

What distinguishes pressure-controlled CMV from volume-controlled CMV?

Pressure-control adjusts based on the pressure, while volume-control adjusts based on the volume delivered.

What does the operator set in a Vol CMV mode?

Ventilator parameters including RR (minimum time triggered mandatory rate), PEEP, FiO2.

How does the patient interact with the ventilator in VC-CMV?

The patient can trigger breaths, but the ventilator controls the size and timing.

In what situations is Continuous Mandatory Ventilation typically employed?

For patients who are unlikely to meet the work of breathing required for adequate ventilation.

What is the significance of compliance and resistance in a Vol CMV mode?

They affect the actual minute ventilation and the effectiveness of the ventilatory support.

What determines the actual RR in a Vol CMV mode?

It differs from the set RR based on patient-triggered activities.

Which modes allow operators to observe pressure, flow, and volume vs. time waveforms?

Vol CMV.

What key feature of VC-CMV assures the operator of necessary ventilation support?

It guarantees the minimum required minute volume based on set mandatory rate and volume.

What happens during a breath in a Vol CMV regarding the control of volume?

The ventilator maintains a consistent flow rate to ensure the tidal volume is delivered.

How does the operator confirm the pressure variability in VC-CMV?

It is confirmed by monitoring fluctuations in pressure in response to patient lung characteristics.

What is the role of adaptive targeting in modern ventilators?

It allows the ventilator to automatically adjust to optimize patient support based on real-time conditions.