Whats Your Mode? Episode i

Image 1. Settings within "Volume Control" a VC-CMVs modality on the FLOW-i anesthesia Delivery system. All highlighted settings may affect patient comfort.

My first episode of my new video series is now available to my news letter subscribers.
I posted a teaser video on YouTube (see below). 

Note- if you signed up to receive my news letter and do not have it in your "in-box" please check your spam folder.

VIDEOS to COME
(a * next to the name indicates this video is only available to news letter subscribers)

VC-CMVd*

VC-IMVs,s
VC-IMVds*
VC-IMVda,s*
VC-IMVd,a*
VC-IMVa,s*

PC-CMVs
PC-CMVa*

PC-IMVs,s
PC-IMVa,s*
PC-IMVa,a*
PC-IMVo,o*

PC-CSVs
PC-CSVr (PAV+)*
PC-CSVr (NAVA)*
PC-CSVa
PC-CSVi (Smart Care)*

To receive these extra videos please sign up for my free news letter by following the link on the page "News Letter". 

ATTRIBUTION
These videos have been conceived from the following two journal articles.  

Respir Care. 2014 Nov;59(11):1747-63. doi: 10.4187/respcare.03057.  A taxonomy for mechanical ventilation: 10 fundamental maxims. Chatburn RL, El-Khatib M, Mireles-Cabodevila E.

Respir Care. 2013 Feb;58(2):348-66. doi: 10.4187/respcare.01839. A rational framework for selecting modes of ventilation. Mireles-Cabodevila E, Hatipoğlu U, Chatburn RL.

I recommend reading both articles to obtain a deeper knowledge and appreciation for the different modes of mechanical ventilation. 


RECOMMENDED PREREQUISITE POSTS/VIDEOS

Targeting Scheme Intro

Targeting Scheme Post

Whats Your Mode?

What’s Your Mode?

Happy 2016! This post is to inform readers on two topics related to this blog.

First

This year I will begin transitioning this blog and my YouTube page to a FREE email subscription based newsletter. Throughout the year I will continue to post content on the blog and brief videos on my YouTube page, however subscribers to my newsletter will receive additional content on the topics of mechanical ventilation and respiratory therapy (e.g. extended more detailed videos, PDF files, etc.).

After December 2016 no additional content will be posted here, however the blog & YouTube page will remain open as an archive.

Image 1. Ventilator Screen shot of Adaptive Support Ventilation, patient safety and comfort targets. 

Second

I will be starting a new video series similar to ones I have already created (e.g. APRV, PC-CMV, Adaptive Pressure Control). The title of this series is “What’s your mode?”

This series will be comprised of approximately 18 videos providing operational transparency to the various modes of mechanical ventilation. I believe this is important because clinicians’ need to understand the boundaries of these modalities which is not always disclosed by the device manufacturer.

The video idea was conceived after reading I believe one of the most brilliant papers and theories on mechanical ventilation “A rational framework for selecting modes of mechanical ventilation” [1]. This paper questions why we use a specific ventilator mode and proposes selecting a mode based on the three central goals of mechanical ventilation; patient safety, patient comfort, and transitioning to liberation. The paper also introduces selecting a mode of mechanical ventilation based on mode capabilities and features to accomplish these goals.

Note- two evident things;

The mode has to be available on the ventilator in use.

The clinician has to be competent and know the capabilities and boundaries of a specific mode.  

If interested in receiving additional content please sign up for the News Letter below or on the page labeled “News Letter”.

CLICK LINK to Sign up

http://eepurl.com/bOs4IX

REFERENCE

[1]. Mireles-Cabodevila, E. Hatipoglu, U. and Chatburn, R. (2013). A rational framework for selecting modes of ventilation. Respiratory Care. 58 (2): 348-364. 

[2]. Respir Care. 2013 Feb;58(2):348-66. doi: 10.4187/respcare.01839. A rational framework for selecting modes of ventilation. Mireles-Cabodevila E, Hatipoğlu U, Chatburn RL.

   

   

Changing Flow Patterns vs. Changing Ventilator Modes

Figure 1: Various flow patterns within VC-CMVs on the Hamilton G5 Ventilator.

When a device operator thinks about changing the inspiratory flow pattern while administering a Volume-Controlled breathing pattern they do not assume it will change the mode of ventilation. 

However newer software in the Servo-i allows the operator to change the flow pattern 

from the traditional constant flow pattern, to either a fully decelerating  flow pattern (similar to PC-CMV) or to adaptive flow (Fig. 2).  The Adaptive Flow pattern was the default in older software which makes Volume Control a Dual Control mode [1].  The operator now has a choice of using Volume Control as a traditional VC-CMV mode by selecting the square waveform or providing a Dual Control breathing pattern by selecting the Adaptive Flow icon. 

Figure 2: Flow patterns available on the Servo-i, courtesy of Robert Chatburn. 

For more information on flow patterns and Dual Control see the below links.

DUAL CONTROL

Dual Targeting Schemes

FLOW PATTERNS

Flow Patterns & Flow Rates

RELATED POSTS

1. The Volume Control Ventilation Fallacy

    Targeting Schemes

The Volume Control Ventilation Fallacy

Volume Control- Continuous Mandatory Ventilation with a “Set-point” targeting scheme (VC-CMV(s)) is likely the most utilized mode of mechanical ventilation in adult patients in North America. This is due to a few a reasons:

1.      VC-CMV is a standard mode on almost every intensive care ventilator and anesthesia delivery system.

2.      VC-CMV is one of the first modes of mechanical ventilation.

3.      VC-CMV is easy to understand in both theory and operation.

4.      VC-CMV is the standard of care when ventilating patients with Acute Respiratory Distress Syndrome (ARDS) and Acute Lung Injury (ALI).

5.      VC-CMV is the standard of care for adult patients intraoperatively.

The key advantage of VC-CMV(s) is the safety and simplicity of the set-point targeting scheme. The operator can manually set all parameters of the volume/flow waveform and adjust the minimum minute ventilation parameters (relating to frequency and tidal volume). “One can quickly trouble-shoot a patient’s situation, so during a change the operator can diagnose the problem and intervene rapidly”. [1]

When one sees a mode of ventilation labeled “Volume Control”, “VC”, “Volume A/C”, or “CMV” it affirms that the breathing pattern delivered to the patient will consist of a constant tidal volume and inspiratory flow waveform (fig. 1) 

Figure 1. Volume Control Ventilation Breath Pattern.

Figure 2. Volume and Flow waveform remains constant even-though compliance decreased to 25, compared to Figure 1.  

regardless of changes in a patient’s respiratory system mechanics and/or inspiratory drive (fig. 2) [2]. Conversely, due to no industry standard for ventilator mode taxonomy and medical device manufacturers marketing schemes the actual breath delivered to the patient does not resemble the predicted breath pattern and may result in a tidal volume much larger than the expected preset value.

How does this happen?

Ventilator Mode Map App

Ventilator Mode Map Mobile App

Due to no industry standard for ventilator mode taxonomy and over 170 unique names for modes of ventilation.  Learning and understanding ventilator mode classification can be problematic.   Ventilator Mode Map provides a easy to use handheld solution.   With this app one can choose from 12 different vendors,  37 different models (with pictures) and provides hundreds of definitions. One would have to review various text books and journal articles to compile this knowledge base.

This app is for android devices, I have a copy on my Samsung Galaxy tablet & Motorola phone, works fine on both devices. Available on Google Play see link below.

GOOGLE PLAY

Ventilator Mode Map

Intelligent Targeting Schemes

A Intelligent targeting scheme is "a ventilator control system that uses artificial intelligence programs such as fuzzy logic, rule based expert systems, & artificial neural networks" (Chatburn, 2012). Examples of modalities that use  Intelligent targeting are Smartcare & IntelliVent-ASV.

Please view the above video for more information on Intelligent targeting schemes.

RELATED POSTS

SmartCare Posts

Free Mechanical Ventilation Handouts

Reference

Chatburn, R. (2012). Standardized Vocabulary for Mechanical Ventilation. Mandu Press. 

*Note- this reference is available under the link free mechanical ventilation handouts.

Optimal Targeting Schemes

A Optimal targeting scheme is a "ventilator control system that automatically adjusts the targets of the ventilatory pattern to either minimize or maximize some overall performance characteristic" (Chatburn, 2002). 

Please view the above video for more information on Optimal targeting. 

RELATED VIDEOS

ASV Playlist

RELATED POSTS

Adaptive Support Ventilation Posts

Free Mechanical Ventilation Handouts

Reference

Chatburn, R. (2012). Standardized Vocabulary for Mechanical Ventilation. Mandu Press. 

*Note- this reference is available under the link free mechanical ventilation handouts.

Adaptive Targeting Schemes

Adaptive targeting schemes use "a control system that allows the ventilator to automatically set some (or all) of the targets between breaths to achieve other preset targets" (Chatburn, 2012). Adaptive Pressure Control is most likely the most recognized and most used modality that uses a adaptive targeting scheme.

 Please review the above video for a more detailed description. 

RELATED VIDEOS
Adaptive Pressure Control Playlist

RELATED POSTS

Adaptive Pressure Control List

Free Mechanical Ventilation Handouts

Reference

Chatburn, R. (2012). Standardized Vocabulary for Mechanical Ventilation. Mandu Press. 

*Note- this reference is available under the link free mechanical ventilation handouts.

Servo Targeting Schemes

Ventilator modes that use Servo targeting schemes are very responsive and provide the most comfort and synchrony in the spontaneous breathing patient. Servo targeting is "a control system for which the output of the ventilator automatically follows a varying input. This means that the inspiratory pressure is proportional to inspiratory effort" (Chatburn, R.). 

The below videos give a brief description of Servo targeting schemes and ventilator modes that use Servo targeting schemes. 

Automatic Tube Compensation

Automatic Tube Compensation is "a feature that allows the operator to enter the size of the patient's endotracheal tube & have the ventilator calculate the tubes resistance & then generate just enough pressure to compensate for the added resistive load" (Chatburn, R. 2012).

RELATED POST/LINKS
Free Mechanical Ventilation Handouts

Servo Targeting 

Reference

Chatburn, R. (2012). Standardized Vocabulary for Mechanical Ventilation. Mandu Press. 

*Note- this reference is available under the link free mechanical ventilation handouts.

Dual Targeting Schemes

Dual targeting schemes are a step above Set-point targeting in regards to engineering hierarchy. These modes can switch from volume-control to pressure-control during the inspiratory phase. 

The above video overviews dual targeting schemes and presents the advantages and disadvantages of these modalities. 

RELATED VIDEOS

Targeting Schemes

Free Mechanical Ventilation Handouts

Reference

Chatburn, R. (2012). Standardized Vocabulary for Mechanical Ventilation. Mandu Press. 

*Note- this reference is available under the link free mechanical ventilation handouts.

Targeting Schemes

A Targeting Scheme is "A model of the relationship between operator inputs and ventilator outputs to achieve a specific ventilatory pattern, usually in the form of a feedback control system" [1]. The targeting scheme describes the main functionality of a ventilator mode and helps one differentiate modes of mechanical ventilation. 

This is not only helpful when classifying a mode for academic purposes, but the knowledge of a targeting scheme is beneficial when selecting a ventilator mode to best match its capabilities to the clinical goals of mechanical ventilation. 

Dumbing Down Ventilator Taxonomy

In a recent letter to the editor “Ventilatory modes. What’s in a name?”[1] Authors provide a strong argument for the need to standardize terminology in regards to mechanical ventilation and propose an oversimplified classification system specifically for non-invasive ventilatory devices. I applaud the authors for their call to action; conversely their viewpoint is neither novel nor applicable to ventilator taxonomy.

Simplifying Mechanical Ventilation

From Global Nerdy @ www.globalnerdy.com

In a recent letter to the editor “Ventilatory modes. What’s in a name?”[1] Authors provide a strong argument for the need to standardize terminology in regards to mechanical ventilation and propose an oversimplified classification system specifically for non-invasive ventilatory devices. I applaud the authors for their call to action; conversely their viewpoint is neither novel nor applicable to ventilator taxonomy.