Continuous mandatory ventilation: Difference between revisions
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'''Continuous mandatory ventilation''' ('''CMV''') is a [[mode of mechanical ventilation]] in which breaths are delivered based on set variables. Still used in the operating room, in previous nomenclature, CMV referred to "controlled mechanical ventilation" ("control mode ventilation"), a mode of ventilation characterized by a ventilator that makes no effort to sense patient breathing effort. In continuous mandatory ventilation, the ventilator can be triggered either by the patient or mechanically by the ventilator. The ventilator is set to deliver a breath according to parameters selected by the operator. "Controlled mechanical ventilation" is an outdated expansion for "CMV"; "continuous mandatory ventilation" is now accepted standard [[nomenclature of mechanical ventilation|nomenclature for mechanical ventilation]]. CMV today can assist or control itself dynamically, depending on the transient presence or absence of spontaneous breathing effort. Thus, today's CMV [[Nomenclature of mechanical ventilation#Continuous mandatory ventilation (CMV)|would have been called ACV]] (assist-control ventilation) in older nomenclature, and the original form of CMV is a thing of the past. But despite continual technological improvement over the past half century, CMV may still be uncomfortable for the patient. |
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'''Volume Controlled Continuous Mandatory Ventilation''' — ('''VC-CMV''') is a [[mode of mechanical ventilation]] where breaths are delivered based on set variables. The patient may initate breaths by attempting to breathe. Once a breath is initated, either by the patient or by the ventilator the set [[tidal volume]] is delivered. |
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==Controlled Mechanical Ventilation== |
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| ⚫ | Continuous mandatory ventilation is associated with profound diaphragm muscle dysfunction and atrophy. <ref name="pmid15201132">{{cite journal|vauthors=Sassoon CS, Zhu E, Caiozzo VJ | title=Assist-control mechanical ventilation attenuates ventilator-induced diaphragmatic dysfunction. | journal=Am J Respir Crit Care Med | year= 2004 | volume= 170 | issue= 6 | pages= 626–32 | pmid=15201132 | doi=10.1164/rccm.200401-042OC | url=https://pubmed.ncbi.nlm.nih.gov/15201132 }}</ref> CMV is no longer the preferred mode of mechanical ventilation. <ref name="pmid21813526">{{cite journal| author=Macintyre N| title=Counterpoint: Is Pressure Assist-Control Preferred Over Volume Assist-Control Mode for Lung Protective Ventilation in Patients With ARDS? No. | journal=Chest | year= 2011 | volume= 140 | issue= 2 | pages= 290–2 | pmid=21813526 | doi=10.1378/chest.11-1052 | doi-access=free }}</ref> |
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'''CMV''' — Controlled Mechanical Ventilation (also called Controlled Volume Control) is the original name for Assist Control. When the addition of a patient initiated breath was added to the mode, Assist Control effectively replaced CMV entirely. Fundamentally, CMV is a volume-controlled mode where the tidal volume and frequency are set to deliver a minute volume with a complete disregard for patient effort. |
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== Volume-controlled CMV == |
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The use of CMV requires the patient be completely unconscious, either pharmacokinetically or otherwise in a [[coma]]. |
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;Other terms used to represent CMV |
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=== Cycle === |
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'''VC-CMV''' — Most commonly referred to as '''Assist Control''' ('''AC''') is a mode of ventilation where breaths are delivered based on set variables. The patient may initate breaths by attempting to breathe. Once a breath is initated, either by the patient or by the ventilator the set [[tidal volume]] is delivered. Assist Control is also called Volume Control or Assist Control Volume Control (AC/VC). |
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== Pressure-controlled CMV == |
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This mode was created out of the need for patient-initiation in breaths. Fundamentally, AC is controlled mechanical ventilation (CMV) with a sensitivity for patient breathing. |
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Pressure control (PC) is a pressure-controlled mode of ventilation. The ventilator delivers a flow to maintain the preset pressure at a preset [[respiratory rate]] over a preset inspiratory time. <ref>MAQUET, "Modes of ventilation in SERVO-i, Invasive and Non-invasive, 2008 MAQUET Critical Care AB, Order No 66 14 692</ref> |
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The pressure is constant during the inspiratory time, and the flow is decelerating. If, for any reason, pressure decreases during inspiration, the flow from the ventilator will immediately increase to maintain the set inspiratory pressure. <ref>MAQUET, "Modes of ventilation in SERVO-s, Invasive and Non-invasive", 2009 MAQUET [[Intensive care medicine|Critical Care]] AB, Order No 66 61 131</ref> |
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The variables required in AC are: tidal volume (V<sub>T</sub>), respiratory rate (f), flow rate and trigger sensitivity (for sensing patient effort). Additional variables like peak-end expiratory pressure (P<sub>EEP</sub>) and pressure support (P<sub>S</sub>) may be added for additional support. |
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== Dual-control modes == |
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{{main|dual-control modes of ventilation}} |
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Dual-control modes are [[pressure control|pressure-control]]led modes with an exhaled [[tidal volume]] target. They work on a breath-by-breath basis and provide pressure-limited, time-cycled breaths, increasing or decreasing the pressure of the next breath as necessary to achieve a user-selected desired tidal volume. They are known by various vendor-specific terms such as pressure-regulated volume control ([[Siemens]]), autoflow ([[Drägerwerk|Dräger]]), adaptive-pressure ventilation (Hamilton Medical), and volume-control plus ([[Covidien]]), among others. |
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== Out-dated terminology == |
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| ⚫ | Many terms have been developed to describe the same [[modes of mechanical ventilation]]. The [[nomenclature of mechanical ventilation]] has become more standardized, and these terms are no longer preferred but may still be seen in older research. <ref name="ReferenceA">Chatburn RL. Classification of ventilator modes: update and proposal for implementation. Respir Care 2007; 52:301–323. {{PMID|17328828}}</ref> There are many different names that were historically used to refer to CMV but now refer to Assist Control. <ref name="ReferenceA"/> Names such as volume control ventilation and volume cycled ventilation in modern usage refer to the Assist Control mode. |
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'''Trigger''' — Breath initiation is based on time or patient initiation. Time is set by respiratory rate (V<sub>f</sub> or RR) and patient initiation is sensed by a flow, volume or pressure trigger and a full ventilator breath (the set tidal volume) is given. |
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==Terms no longer accepted== |
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Many terms have been developed to describe the same [[modes of mechanical ventilation]]. [[Nomenclature of mechanical ventilation]] has become more standardized and these terms are no longer preferred but still may be seen in older research. |
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* A/C |
* A/C |
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* CMV |
* CMV |
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* Volume |
* Volume assist/control |
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* Volume |
* Volume control |
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* Volume |
* Volume limited ventilation |
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* Volume |
* Volume controlled ventilation |
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* Controlled |
* Controlled ventilation |
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* Volume |
* Volume targeted ventilation |
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==See also== |
==See also== |
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*[[List of modes of mechanical ventilation by category]] |
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*[[Modes of mechanical ventilation]] |
*[[Modes of mechanical ventilation]] |
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*[[Pressure controlled continuous mandatory ventilation]] |
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*[[Volume Controlled Continuous Mandatory Ventilation]] |
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*[[Pressure controlled intermittent mandatory ventilation]] |
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*[[Volume Controlled Intermittent Mandatory Ventilation]] |
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*[[Volume controlled intermittent mandatory ventilation]] |
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*[[Pressure Controlled Continuous Mandatory Ventilation]] |
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*[[Pressure Controlled Intermittent Mandatory Ventilation]] |
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==References== |
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{{reflist|30em}} |
{{reflist|30em}} |
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[[Category:Respiratory therapy]] |
[[Category:Respiratory therapy]] |
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[[Category:Mechanical ventilation]] |
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Latest revision as of 19:21, 28 August 2023
Continuous mandatory ventilation (CMV) is a mode of mechanical ventilation in which breaths are delivered based on set variables. Still used in the operating room, in previous nomenclature, CMV referred to "controlled mechanical ventilation" ("control mode ventilation"), a mode of ventilation characterized by a ventilator that makes no effort to sense patient breathing effort. In continuous mandatory ventilation, the ventilator can be triggered either by the patient or mechanically by the ventilator. The ventilator is set to deliver a breath according to parameters selected by the operator. "Controlled mechanical ventilation" is an outdated expansion for "CMV"; "continuous mandatory ventilation" is now accepted standard nomenclature for mechanical ventilation. CMV today can assist or control itself dynamically, depending on the transient presence or absence of spontaneous breathing effort. Thus, today's CMV would have been called ACV (assist-control ventilation) in older nomenclature, and the original form of CMV is a thing of the past. But despite continual technological improvement over the past half century, CMV may still be uncomfortable for the patient.
Expected outcomes and considerations.
[edit]Continuous mandatory ventilation is associated with profound diaphragm muscle dysfunction and atrophy. [1] CMV is no longer the preferred mode of mechanical ventilation. [2]
Volume-controlled CMV
[edit]Limit
[edit]Limits in VC-CMV may be set and pressure based. The ventilator will attempt to deliver the set tidal volume by utilizing whatever pressure is required to reach its setting. A pressure limit may be added to limit damage to the lungs (barotrauma).
Cycle
[edit]Expiration cycling can be set by time or the pressure limit. Once the Ti (inspiratory time) is reached, or a pressure limit is reached, the ventilator will cycle into expiratory mode and allow passive exhalation until another breath is triggered.
Pressure-controlled CMV
[edit]Pressure control (PC) is a pressure-controlled mode of ventilation. The ventilator delivers a flow to maintain the preset pressure at a preset respiratory rate over a preset inspiratory time. [3]
The pressure is constant during the inspiratory time, and the flow is decelerating. If, for any reason, pressure decreases during inspiration, the flow from the ventilator will immediately increase to maintain the set inspiratory pressure. [4]
Dual-control modes
[edit]Dual-control modes are pressure-controlled modes with an exhaled tidal volume target. They work on a breath-by-breath basis and provide pressure-limited, time-cycled breaths, increasing or decreasing the pressure of the next breath as necessary to achieve a user-selected desired tidal volume. They are known by various vendor-specific terms such as pressure-regulated volume control (Siemens), autoflow (Dräger), adaptive-pressure ventilation (Hamilton Medical), and volume-control plus (Covidien), among others.
Out-dated terminology
[edit]Many terms have been developed to describe the same modes of mechanical ventilation. The nomenclature of mechanical ventilation has become more standardized, and these terms are no longer preferred but may still be seen in older research. [5] There are many different names that were historically used to refer to CMV but now refer to Assist Control. [5] Names such as volume control ventilation and volume cycled ventilation in modern usage refer to the Assist Control mode.
- Assist/control
- A/C
- CMV
- Volume assist/control
- Volume control
- Volume limited ventilation
- Volume controlled ventilation
- Controlled ventilation
- Volume targeted ventilation
See also
[edit]- Continuous spontaneous ventilation
- List of modes of mechanical ventilation by category
- Modes of mechanical ventilation
- Pressure controlled continuous mandatory ventilation
- Pressure controlled intermittent mandatory ventilation
- Volume controlled intermittent mandatory ventilation
References
[edit]- ^ Sassoon CS, Zhu E, Caiozzo VJ (2004). "Assist-control mechanical ventilation attenuates ventilator-induced diaphragmatic dysfunction". Am J Respir Crit Care Med. 170 (6): 626–32. doi:10.1164/rccm.200401-042OC. PMID 15201132.
- ^ Macintyre N (2011). "Counterpoint: Is Pressure Assist-Control Preferred Over Volume Assist-Control Mode for Lung Protective Ventilation in Patients With ARDS? No". Chest. 140 (2): 290–2. doi:10.1378/chest.11-1052. PMID 21813526.
- ^ MAQUET, "Modes of ventilation in SERVO-i, Invasive and Non-invasive, 2008 MAQUET Critical Care AB, Order No 66 14 692
- ^ MAQUET, "Modes of ventilation in SERVO-s, Invasive and Non-invasive", 2009 MAQUET Critical Care AB, Order No 66 61 131
- ^ a b Chatburn RL. Classification of ventilator modes: update and proposal for implementation. Respir Care 2007; 52:301–323. PMID 17328828