Advance Breathing System (ABS)- Disassembly, Cleaning, & Reassembly

Disassembly, Cleaning, & Reassembly for the Advance Breathing System on the Aespire, Avance, & Aisys anesthesia delivery systems.

HYPERCAPNEA & ATELECTRAUMA: MIMICKING APRV

In a previous post "APRV in the operating room is it practical?"  I argue that bringing a ICU ventilator into the operating room to utilize APRV is not practical and may lead to hypoventilation and hypoxia due to administration of anesthetic agents [1].

During surgical procedures the patient is maintained in stage 3 of anesthesia known as the "surgical stage". Stage 3 is broken down into four distinct planes, "from onset of automatic respiration to respiratory paralysis" [2]. The patient is usually maintained in Plane 3 (intercostal muscle paralysis) or Plane 4 (diaphragmatic paralysis) leading to the cessation of spontaneous breaths.

One key advantage of APRV is that the patient may breathe spontaneously contributing to the overall minute volume, with the termination of spontaneous efforts the patient will become severely hypercapnic.

Below is an image (fig 1) I captured from a "Pressure Control Ventilation Simulator" [3] demonstrating an ARDS patient on APRV.

Figure 1. Pressure Control Ventilation Simulator, notice patients PaCO2 at 100.7 mmHg.

Notice in figure 1 the outcome for a patient not contributing to the overall minute ventilation the PaCO2 would be 100.7 mmHg. 

Another example of how APRV maybe harmful in the operating room is when trying to mimic APRV with a anesthesia delivery system.

A Synopsis of Strategies in Difficult Intra-Operative Ventilation

Image from: http://www.esicm.org

“Strategies in Difficult Intra-Operative Ventilation” was a continuing education course originally presented at the 2012 American Academy of Anesthesiologist convention. 

Now the course is available online through the ASA website for continuing education units. I would not recommend this course for the ICU practitioner because it overviews strategies that we practice daily or weekly, however for the anesthesia provider that is not familiar with lung protective strategies the course may be beneficial. 

Below is a synopsis of the course and a hyperlink to the website. 

What the Sales Guy Won't Tell You. Why You Won't Save $200,000 in Anesthetic Agent

In a previous post "How to Save $200,000 in Anesthetic Agent" I demonstrated how one anesthesia department could save close to a quarter of a million dollars by changing efficiency. I presented this many times using a mathematical modeling tool (Anesthesia Agent Analysis. S. Richey & R. Hazlett)  a colleague and myself created. 

Anesthesia Companies have used this same modeling in their marketing and device claims in regards to saving anesthetic agent. 

Example 1: Draeger Medicals "Low Flow Wizard" 
This is a decision support tool to help practitioners feel comfortable with using low to minimal flow anesthesia. 

Example 2: GE Healthcare's "ecoFlow"
This is GE's product to compete with & similar to the Low Flow Wizard (Draeger's was released first).

ecoFlow

However, these tools are not novel. 

Dr. James H. Philip, the creator of "Gas Man" [1] has been a advocate, and teacher of minimal flow & closed system anesthesia for almost two decades. 
Dr. Philips software & courses demonstrate that one can provide minimal flow anesthesia using any modern day anesthesia delivery system, not just the Draeger Apollo or GE Avance with ecoFlow. 

The key factor in minimal flow anesthesia is patient safety, which translates to patient monitoring, which is not accomplished by the Low Flow Wizard or ecoFlow. These tools only look at the anesthesia device (gas uptake & system leaks) not hemodynamic status, metabolic demand, SpO2, EtCo2, rebreathed gas, etc. 

Additionally, the medical device companies marketing claims provide a false prediction of actual cost savings related to decreased anesthetic agent usage. 

In the following post I will present why you will not obtain these savings.

Waveform of the Week

Waveform of the week 

I posted a patient ventilator asynchrony case on the GMEP Media Gallery.

Here is the link for viewing:

https://gmep.org/media/14733

Rebuttal to APC a False Sense of Security

Image 1: Laparoscopic surgery.

In a previous post "Adaptive Pressure Control Ventilation during Anesthesia: a False Sense of Security", I argue that the anesthesia provider should use this mode with caution and described how the mode reacts during changes in pulmonary mechanics. 

After reading the post one could assume that I'm against using this mode of ventilation.

However, I believe this mode has many advantages. 

Determinants and Limits of the Bellows: The Katz Study

Image 1: Draeger Narkomed 2c Anesthesia Delivery System.

In a previous post "Determinants and Limits or the Draeger Narkomed Anesthesia Machine in Regards to Ventilating the Morbidly Obese Patient", I tried to calculate the largest patient a bellows system could ventilate safely. 

I concluded that if you wanted to deliver a minute ventilation greater than 9 liters per minute, using conventional ventilator settings (tidal volume of 10 ml/kg/IDBW) that the operator would run into issues. 

Minimal Fresh Gas Flow: "A Reassuringly Safe Anesthetic Technique".

Image 1: Minimal FGF on the FLOW-i anesthesia delivery system

In this months Canadian Journal of Anesthesia authors of the article "Brief Review: Theory and Practice of Minimal Fresh Gas Flow Anesthesia", conclude that with newer anesthesia delivery systems that using minimal fresh gas flow and third generation of inhaled anesthetic agents is a safe technique with many benefits [1]. 

The authors review advantages, potential limitations, and safety considerations when utilizing minimal fresh gas flow technique (mFGF). 

Universal Anesthesia Machine

900 ML are you Serious?

Puffer Fish, by Karen Garrett de luna

Anesthesia Machines: Bellows vs. Piston

Correspondence 2008.

Attached are three documents:

1. Article on gas consumption in bellow driving anesthesia machines, comparing both Draeger & GE, this is one of the main reasons Draeger switched to a piston (to conserve on fresh gas, allowing for minimal flow anesthesia < or = 1/4 liter total fresh gas flow).

2. Abstract comparing the Apollo (piston) & Aisys (bellows) in regards to the accuracy of tidal volume delivery, with the new technology the Aisys can also accurately deliver both large & small tidal volumes. 

3. A letter I wrote to a customer on the limitations of the (Draeger's) Narkomed 2B (an older bellows machine) in regards to ventilating the morbidly obese patient. 

Determinants and limits of the Draeger Narkomed Anesthesia machine in regards to ventilating the morbidly obese patient.

*Correspondence from 2007

Purpose

Determinants and limits of the Draeger Narkomed Anesthesia machine in regards to ventilating the morbidly obese patient.

How to Save $200,000.00 in Anesthetic Agent

Due to the current health care reform legislation many hospitals are implementing recommendations from the "Institute for Health care Improvement" in  regards to reducing or eliminating wasted time, money, and energy in health care.
One area to eliminate waste and to increase savings is focusing on anesthetic agent use during general anesthesia procedures.

Adaptive Pressure Control Ventilation during Anesthesia: A False sense of Security

Adaptive pressure control (APC) is a ventilator modality which has been applied safely in intensive care units for greater than a decade. The mode delivers a pressure control breath that maintains a target tidal volume (Vt) at the lowest possible pressure, independently of changes in pulmonary mechanics.

Within the last few years in the United States ventilator manufactures have made this mode available on their newer generation anesthesia machines. Manufactures highly recommend APC during surgical procedures in which positioning or insufflation of the abdomen creates dramatic changes in pulmonary mechanics (e.g. laparoscopic, thoroscopic, prostatectomy).