Ventilator Breath Types and Sequences

Flashcards covering the fundamentals of ventilator breath types, support levels, and modes of ventilation as discussed in the lecture transcript.

Volume Control Ventilation

A ventilation mode that provides a consistent tidal volume ($V_T$) with every breath, making minute ventilation easy to predict while utilizing a fixed, set flow rate.

Pressure Control Ventilation

A ventilation mode that provides a consistent peak inspiratory pressure ($PIP$) and uses a variable flow rate often more comfortable for the patient.

Full Support

A level of ventilator support characterized by a set respiratory rate of $8$ breaths per minute or higher, intended to let the ventilator perform most of the work of breathing.

Partial Support

A level of ventilator support characterized by a set respiratory rate of $6$ breaths per minute or less, where the patient performs some or all of the work of breathing.

Mandatory Breath

A breath delivered by the machine based on clinician-set parameters, such as a specific $V_T$ and flow rate in volume control, or pressure and inspiratory time ($I-time$) in pressure control.

Spontaneous Breath

A breath that is both initiated (triggered) and ended (cycled) by the patient on their own.

Assisted Breath

A breath that the patient either triggers or cycles on their own, but is supplemented by the ventilator to provide a boost in pressure or volume.

Trigger

The physiological or machine-set starting point of a breath.

Cycle

The physiological or machine-set ending point of a breath.

Pressure Support

An added level of pressure during a spontaneous breath that acts as a boost to increase tidal volume and decrease the patient's work of breathing.

Assist Control (AC) Ventilation

Also known as Continuous Mandatory Ventilation ($CMV$), this mode delivers only mandatory breaths at a set minimum rate, though patients can trigger additional mandatory-style breaths.

Synchronized Intermittent Mandatory Ventilation (SIMV)

A mode of ventilation that delivers a mix of mandatory breaths at a set rate and spontaneous breaths for any efforts the patient makes above that rate.

Breath Stacking

A condition where the ventilator delivers a machine breath on top of a patient's spontaneous breath, which modern ventilator refractory periods help prevent.

Asynchrony

A situation where the patient is 'fighting' the ventilator because the machine's delivery does not align with the patient’s natural respiratory drive.

Wean Trial

A brief period where a patient on full support is allowed more of the work of breathing to rehabilitate respiratory muscles and prevent muscle atrophy.

CPAP (Continuous Positive Airway Pressure)

A mode of spontaneous breathing where a consistent level of expiratory pressure is provided, and all work of breathing is typically performed by the patient unless pressure support is added.