Many terms are used in mechanical ventilation, some are specific to brand, model, trademark and mode of mechanical ventilation. There is a standardized nomenclature of mechanical ventilation that is specific about nomenclature related to modes, but not settings and variables. Terms are now split into acronyms of CONTROL VARIABLE + BREATH SEQUENCE + TARGETING SCHEME. As in PC-CMV, Pressure Controlled Continuous Mandatory Ventilation. The term trigger denotes the criteria that starts inspiration and cycle denotes the criteria that stops it. The target variable should not be confused with the cycle variable or the control variable. The target variable only sets an upper limit for pressure, volume or flow.
Control variable
The physical parameter that controls the breath in accordance with the equation of motion
Volume controlled ventilation is ventilation where both volume and flow are controlled by the ventilator. Normally, flow is set to a fixed amount, meaning volume increases linearly over time. Any mode that relies on flow to control inspiration falls under the VC- category.
Pressure controlled ventilation is where pressure as a function of time is controlled by the ventilator. Normally, pressure is set to a specific amount for a specific breath duration, letting volume and flow vary according to patient demands. Any mode that relies on pressure to deliver a breath falls under the PC- category.
Time control (TC)
Rarely breaths can be purely time controlled. An example is intrapulmonary percussive ventilation. Here only time is set by the operator and pressure and flow change obeying the equation of motion.
Commonly known as “Assist/Control”; CMV is a breath sequence for which spontaneous breaths are not possible between mandatory breaths because every patient trigger signal in the trigger window produces a machine cycled inspiration. Machine triggered mandatory breaths may be delivered at a preset rate. Therefore, in contrast to IMV, the mandatory breath frequency may be higher than the set frequency but never below it. In some pressure controlled modes on ventilators with an active exhalation valve, spontaneous breaths may occur during mandatory breaths, but the defining characteristic of CMV is that spontaneous breaths are not permitted between mandatory breaths. ;Terms replaced by VC-CMV
IMV is a form of ventilation where the ventilator delivers mandatory breaths, but spontaneous breaths are possible between mandatory breaths. Mandatory breaths can be delivered at a set frequency, or can be delivered whenever breath volume per minute falls below a set point. ;Terms replaced by VC-IMV
Continuous Spontaneous Ventilation — CSV is a breath sequence for which all breaths are spontaneous. Terms no longer in use:
Spont
Spontaneous
Targeting schemes
Set point - e.g. - PC-CSVs is the tag for Pressure support.
Adaptive - e.g. - PC-IMVa,a is the tag for VC+.
Optimal - e.g. - PC-IMVoi, oi is the tag for Adaptive Support Ventilation, technically due only to minor safety algorithms, if not it would only be "optimal" but not "intelligent".
Dual - e.g. - VC-CMVd is the tag for CMV + pressure limited ventilation.
Intelligent - e.g. - PC-IMVoi, oi is the tag for Adaptive Support Ventilation and for INTELLiVent-ASV.
Mandatory breath
Mandatory Breath is a breath type during mechanical ventilation for which inspiration is machine triggered and/or machine cycled. ;Terms no longer in use:
Machine breath
mechanical breath
Spontaneous breath
Spontaneous Breaths are a breath type for which inspiration is both patient triggered and patient cycled. Applies to assisted or unassisted breathing.
Assisted ventilation or assisted breath references ventilation for which a machine provides some or all of the work of breathing. ;Terms no longer in use:
Patient triggered ventilation
Patient triggered breath
Patient triggered breath
Patient triggered breath — A breath that is initiated by the patient, independent of ventilator settings for frequency. ;Terms no longer in use
Patient assisted breath
assisted breath
Autotriggering
Autotriggering — Autotriggering is the unintended initiation of breath delivery by the ventilator, e.g., by an external disturbance such as movement of the breathing tube or an inappropriate trigger sensitivity setting. ;Terms no longer in use:
