physics

Nomenclature of mechanical ventilation

Nomenclature of mechanical ventilation is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nomenclature of mechanical ventilation rather than just read about it. In short: The nomenclature of mechanical ventilation in the respiration of patients in medical treatment varies widely across associated hardware and modes of operation, with some terms specific to device brand, model, trademark, or mode of mechanical ventilation. While there is a standardized nomenclature of mechanical ventilation for modes, this is not the case for settings and variables.

Key takeaways

Nomenclature of mechanical ventilation belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nomenclature of mechanical ventilation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nomenclature of mechanical ventilation from memory before moving on to harder problems.

Reference excerpt

The nomenclature of mechanical ventilation in the respiration of patients in medical treatment varies widely across associated hardware and modes of operation, with some terms specific to device brand, model, trademark, or mode of mechanical ventilation. While there is a standardized nomenclature of mechanical ventilation for modes, this is not the case for settings and variables. However, these terms can be categorized using a schema that combines control variables, breath sequences, and targeting schemes. 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. The term trigger (commonly flow or pressure) denotes the criterion that starts inspiration, and cycle denotes the criterion that stops it.

Control variables The control variable is the physical parameter that controls the breath in accordance with the equation of motion: i.e. Pressure = Elastance*Volume + Resistance*Flow.

Volume control (VC) 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-(insert mode of ventilation) category.

Pressure control (PC) Pressure controlled ventilation is ventilation 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-(insert mode of ventilation) category.

Time control (TC) Purely time controlled ventilation can be used, although rarely, as for example in intrapulmonary percussive ventilation. In this type of ventilation only time is set by the operator, and pressure and flow change in line with the equation of motion. Any mode that relies on time to deliver a breath falls under the TC-(insert mode of ventilation) category.

Breath sequences

Continuous mandatory ventilation (CMV) CMV is a form of ventilation where the ventilator can assist or control itself dynamically, depending on the transient presence or absence of spontaneous breathing effort by the patient. The following terms have been replaced by the VC-CMV category, as defined above.

Assist/Control A/C ACV CMV Volume Assist/Control Volume Control Volume Limited Ventilation Volume Controlled Ventilation Controlled Ventilation Volume Targeted Ventilation The following terms have been replaced by the PC-CMV category, as defined above.

Assist/Control A/C ACV CMV Pressure Assist/Control Pressure Control Pressure Limited Ventilation Pressure Controlled Ventilation Pressure Targeted Ventilation

Intermittent mandatory ventilation (IMV) 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 with spontaneous breaths occurring in between, or can be delivered whenever breath volume per minute falls below a set point. The following terms have been replaced by the VC-IMV category, as defined above.

Synchronized Intermittent Mandatory Ventilation SIMV The following terms have been replaced by the PC-IMV category, as defined above.

Synchronized Intermittent Mandatory Ventilation SIMV

Continuous spontaneous ventilation (CSV) Main article: Continuous spontaneous ventilation CSV is a form of ventilation where all breaths in the breath sequence are spontaneous. The following terms are no longer in use:

spont spontaneous

Targeting schemes

Mandatory breath Mandatory breath is a breath type during mechanical ventilation in which inspiration is machine triggered and/or machine cycled.

Terms no longer in use The following terms are no longer in use:

machine breath mechanical breath

Spontaneous breath Spontaneous breath is a breath type during mechanical ventilation in which inspiration is both patient triggered and patient cycled. It applies to assisted or unassisted breathing.

Assisted ventilation or breath Assisted ventilation or assisted breath is a breath type during mechanical ventilation in which a machine provides some or all of the work of breathing. The following terms are no longer in use:

patient triggered ventilation patient triggered breath

Patient triggered breath Patient triggered breath is a breath that is initiated by the patient, independent of ventilator settings for frequency. The following terms are no longer in use:

patient assisted breath assisted breath

Autotriggering Autotriggering is the unintended initiation of breath delivery by the ventilator, due to an external disturbance such as movement of the breathing tube or an inappropriate trigger sensitivity setting. The following term is no longer in use:

autocycling

Other terms relevant to targeting schemes Set point – e.g. PC-CSVs is the tag for pressure support. Adaptive – e.g. in PC-IMVa, a is the tag for VC+. Optimal – e.g. in PC-IMVoi, oi is the tag for Adaptive Support Ventilation (ASV) when 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. Biovariable – e.g. PC-CSVb is the tag for Variable Pressure Support. Servo – e.g. PC-CSVr is the tag for NAVA. Intelligent – e.g. PC-IMVoi is the tag for Adaptive Support Ventilation (ASV) and for INTELLiVent-ASV.

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. PS – Pressure Support

Time related I:E – Inspiratory : Expiratory ratio Thigh – Time set for inhalation Tlow – Time set for exhalation iT – Inspiratory Time

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Nomenclature of mechanical ventilation

Start with the simplest possible case. Write down what Nomenclature of mechanical ventilation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nomenclature of mechanical ventilation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nomenclature of mechanical ventilation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nomenclature of mechanical ventilation

In research: Nomenclature of mechanical ventilation appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nomenclature of mechanical ventilation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nomenclature of mechanical ventilation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mechanical ventilation, Pulmonology, Respiratory therapy, so understanding it makes those chapters shorter.
In everyday life: Look for Nomenclature of mechanical ventilation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Nomenclature of mechanical ventilation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nomenclature of mechanical ventilation means in your own words.
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Frequently asked questions

What is Nomenclature of mechanical ventilation in simple terms?

Why does Nomenclature of mechanical ventilation matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nomenclature of mechanical ventilation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nomenclature of mechanical ventilation.