Nomenclature of mechanical ventilation
Many terms are used in mechanical ventilation, some are specific to brand, model, trademark and mode of mechanical ventilation.[1] There is a standardized nomenclature of mechanical ventilation that is specific about nomenclature related to modes, but not settings and variables.[2]
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 (commonly flow or pressure) 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 Control (VC)
Volume controlled breath application is done by way of controlling flow. This can be measured by the tidal volume delivered per unit time. Once the ventilator has decided the set volume has been achieved, the inspiratory flow stops.
Any mode that relies on flow to control inspiration falls under the VC- category.
Pressure Control (PC)
Pressure controlled breaths are concerned only with pressure achieved within the circuit. Once the set pressure has been achieved, inspiration stops when the cycle criteria is met.
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.
Breath Sequence
Continuous Mandatory Ventilation (CMV)
Every breath is mandatory (i.e.,inspiration is patient or machine trigged and machine cycled).[3]
- Terms replaced by VC-CMV
- Assist/Control
- A/C
- CMV
- Volume Assist/Control
- Volume Control
- Volume Limited Ventilation
- Volume Controlled Ventilation
- Controlled Ventilation
- Volume Targeted Ventilation
- Terms replaced by PC-CMV
- Assist/Control
- A/C
- CMV
- Pressure Assist/Control
- Pressure Control
- Pressure Limited Ventilation
- Pressure Controlled Ventilation
- Pressure Targeted Ventilation
Intermittent Mandatory Ventilation (IMV)
Volume Controlled Intermittent Mandatory Ventilation — (VC-IMV) Mechanical ventilation with preset tidal volume and inspiratory flow. Spontaneous breaths (i.e., inspiration is patient triggered and patient cycled) can exist between mandatory breaths.[4]
- Terms replaced by VC-IMV
- Synchronized Intermittent Mandatory Ventilation
- SIMV
- Terms replaced by PC-IMV
- Synchronized Intermittent Mandatory Ventilation
- SIMV
Continuous Spontaneous Ventilation
Continuous Spontaneous Ventilation — CSV is any mode of mechanical ventilation where every breath is spontaneous (i.e., patient triggered and patient cycled).
- Terms no longer in use
- Spont
- Spontaneous
Targeting schemes
- Set point - eg - PC-CSVs is the tag for Pressure support.
- Adaptive - eg - PC-IMVa,a is the tag for VC+.
- Optimal - eg - PC-IMVoi,oi is the tag for Adaptive Support Ventilation.
- Dual - eg - VC-CMVd is the tag for CMV + pressure limited ventilation.
- Biovariable - PC-CSVb is the tag for Variable Pressure Support.
- Servo - eg - PC-IMVr,r is the tag for NAVA.
- Intelligent - eg - PC-IMVoi,oi is the tag for Adaptive Support Ventilation.
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 Breath
Assisted Ventilation or assisted breath references ventilation (or breath) 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
- Autocycling
Non-standardized terminology
The following are terms that are included in modes of mechanical ventilation but are not yet included in the standardized nomenclature.
Volume related
- Vt — Tidal volume
- Ve — Minute ventilation
- Amplitude — High-frequency ventilation (Active)
Pressure related
- Pip — Peak inspiratory pressure
- Pplat — Plateau pressure (airway)
- Mpaw — Mean airway pressure
- EPAP — Pressure applied to exhalation
- IPAP — Pressure applied to inhalation
- Phigh — Highest pressure attained, similar to Pip; this is a constant pressure.
- Plow — Pressure that Phigh drops to during expiratory time (Tlow)
- PEEP — Positive end-expiratory pressure, pressure created by a backpressure valve.
- CPAP — Continuous positive airway pressure
- Δp — Delta-P, the change in pressure from the highest pressure to the lowest pressure.
Time related
- I:E — Inspiratory:Expiratory ratio
- Thigh — Time set for inhalation.
- Tlow — Time set for exhalation.
References
- ↑ Chatburn RL, Volsko TA, Hazy J, Harris LN, Sanders S (2011). "Determining the Basis for a Taxonomy of Mechanical Ventilation.". Respir Care 57 (4): 514–24. doi:10.4187/respcare.01327. PMID 22004898.
- ↑ "Preferred Nomenclature for Mechanical Ventilation for Manuscripts Submitted to RESPIRATORY CARE". Respiratory Care Journal. Retrieved 9 June 2012.
- ↑ du Toit PW, Ungerer MJ (1977). "[Nomenclature in respiratory failure, mechanical ventilation and related technics].". S Afr Med J 52 (26): 1030–1. PMID 609974.
- ↑ Donn SM (2009). "Neonatal ventilators: how do they differ?". J Perinatol. 29 Suppl 2: S73–8. doi:10.1038/jp.2009.23. PMID 19399015.
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