Today, I discuss adaptive support ventilation (ASV), an amazing closed-loop mode that is available only on Hamilton ventilators.
Today's Guests
Michael Schauf
Bio & Critical Care Triad Podcast
Jean Michel Arnal
COI: Research director for Hamilton
Interesting Aspects
- Closed-mode ventilation that varies between PCV, PSV, and SIMV-P
- Open (floating) valve
- Gives PC breaths with targeted volume for non-spont
- Proximal flow sensor
Initial Settings
%MinVol (% Minute Ventilation)
Suggested initial setting for a normal patient: 100% (ARDS: 120%) (Mike starts at 110% to account for deadspace)
For adults, minute volume is calculated at 0.1 l per kg of IBW. For a patient with IBW = 70 kg, 100% MinVol results in 7 l/min, 50% MinVol is 3.5 l/min, 200% MinVol is 14 l/min.
For pediatric patients, minute volume is calculated in a range from 0.3 l per kg for IBW = 3 kg to 0.1 l per kg for IBW = 30 kg.
PEEP/CPAP
Based on oxygenation needs
Oxygen
Suggested initial setting: 50% (or according to your ICU standard)
Controls: In the Controls window, check the default settings. If required, adjust the following
settings according to the patient’s condition:
Maximum pressure set by ASV (Pasv Limit)
Default for normal patients: 30 cmH2O
Flow trigger
Pressure ramp (P-ramp)
Expiratory trigger sensitivity (ETS)
When Not to Use It
- Leaks (BPF, open pneumo, cuff leak)
- Abnormal Breathing Patterns
- Severe metabolic acidosis
Tidal Volumes Delivered in One Study
from this paper
ASV Quickstart Guide
Arnal on the Basics
Baedorf-Kassis on ASV as a Lung-Protective Strategy
Mechanical Power is Lower in ASV 1.1 Compared to Conventional
RCT Crossover in ARDS Patients
Bibliography of Evidence from Hamilton
ASV_bibliography_en_ELO20151136S.08
Hamilton's Training Page on ASV
- ASV Education
- Otis and Mead Equation
Intellivent
Safety and efficacy of a fully closed-loop control ventilation (IntelliVent-ASV®) in sedated ICU patients with acute respiratory failure: a prospective randomized crossover study [10.1007/s00134-012-2548-6]
Additional New Information
More on EMCrit
Additional Resources
- Friend to the show, George Douros sent in his Hamilton Cheat Cards, including ASV
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My team uses this mode extensively. 1) first breath needs to go into the patient. Don’t hit start and then connect it. 2) I have heard reports of patients who couldn’t tolerate the drop in mean airway pressure you necessarily get when it’s running the PRVC algorithm.
Happy to elaborate.
Ryan
My flight program generally uses ASV as an initial mode of ventilation when we intubate or pick up an intubated patient on a scene call to cut down on task saturation, but we are encouraged to move them to a different mode (usually SIMV) as soon as we are able. We got the Hamilton vents pretty recently and I think that there is still some skepticism about using an automated mode, especially in such a dynamic environment where both audio and visual alarms are less noticeable. I appreciate you doing this piece. It’s good to hear from some experts on… Read more »
We just got Hamilton T1s at the beginning of the year and ASV is our 1st line mode for intubated patients with PCV+ as a backup. ASV has been amazing at ventilating the majority of our patients appropriately while also reducing the cognitive load during stressful calls. This podcast couldn’t have came at a better time!
We got T1s as transport ventilators and quickly realized that those small cubes could easily replace all our big Dräger ICU ventilators because every aspect of the Hamilton is better… Sometimes we replace a Dräger with a Hamilton, put in the same settings, and ventilation becomes better. Regarding ASV: One thing I‘d like to highlight is the capability of a smooth transition between controlled ventilation of an apnoeic patient over assisted breaths to complete spontaneous breathing. If the patients‘ spontaneous minute volume is 3, but you have set it to 6, ASV is going to support the patient to reach… Read more »
Any experiences or data on the reliability of PEEP trials on ASV? I would imagine this to be challenging as the vent will keep adjusting. How do you pick the best PEEP in this setting? Very interested to hear everyone’s thoughts and opinions on this. Thanks.
We use Hamilton’s at my 2 hospitals. ASV works pretty well…. but usually neither RTs nor our e-ICU partners like it, because they want more control. Also, if there is dyssynchrony, they need to be pretty deeply sedate for it. Which keeps the ICU nurses happy, but not so good for early vent freedom.
We are using ASV for many years now , one of the condition that I was let down by ASV mode during COVID is when we had to paralyze patient, I found out that patients hupoventilate on that mode and eventually becomes hypoxic
An intriguing discussion might be priced at comment. I do think you should write much more about this topic, it will not often be a taboo subject but generally, folks are insufficient to speak on such topics. To another. Cheers cookie clicker
What about using this mode during NIPPV for COPD patient (I managed few cases like this with good outcome)? If I got it right it shares some key principles with AVAPS (emcrit 341).