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Rapidly Increase MAC Using The “Hands’On” Technique

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Sustainability in the OR – eNewsletter

Rapidly Increase MAC Using The “Hands’On” Technique

ISSUE 5 – 2023

In our previous Sustainability e-Newsletter, we discussed multiple opportunities to further reduce oxygen and volatile agent waste.

Today’s e-newsletter presents how to make rapid changes in anesthetic concentration using the “hands-on technique.”

All providers have instances during anesthesia delivery when they want to quickly deepen the anesthetic in response to indications that the patient is “light’ relative to the surgical stimulus. Some reach for the vaporizer, dial up the concentration and increase the fresh gas flows. Others choose a more sustainable approach of bolusing  anesthetic or analgesic medications via the IV route.

Below are FOUR SUSTAINABILITY TIPS for making rapid changes in volatile anesthetic concentration using the “hands-on technique.”

1.  Increase MAC sustainably

If you prefer to use volatile agent to rapidly increase the patient’s MAC with sustainability in mind, keep your “hand on” the vaporizer and increase to high concentration SEVO (7 – 8%) while maintaining your low flow. This is in contrast to increasing to a moderately high concentration (4 – 5%) at high flows.

2.  Keep your hand on the dial
Watch the end-tidal % increase to your desired MAC and then reduce the concentration to a more suitable level. Do not take your hand off the dial until you reduce the concentration in order to avoid inadvertently overdosing the patient from your high-concentration intervention.

3.  Benefit from low-flow

This high-concentration / low-flow technique avoids producing large amounts of waste gas that would occur with the high-flow technique, especially if the provider forgets to turn the flows back down.

4.  Know the numbers

The record below is an example of increasing to high flows to raise the anesthetic concentration rapidly but forgetting to return to low flow. You will notice 45 mins at 5.5 L/M flow with 2.1 – 3.4% inspired Sevoflurane. Compared to remaining at 1 L/M flow, this amounted to over 200 additional liters of waste gas (containing up to 3.4% Sevo) that was unnecessarily released into the atmosphere.

Alternatively, and for providers who are uncomfortable with briefly increasing to high concentrations of sevoflurane, bolus an IV anesthetic (propofol or other) and/or narcotic while gradually increasing your concentration of volatile anesthetic at low flows.

– Today’s Takeaways –

In response to “light” anesthesia, choose IV boluses. If you prefer to use volatile agent, deliver high concentration at low flow and keep your hand on the vaporizer.

Next time in Sustainability in the OR: ”Anesthesia for bronchoscopies with sustainability in mind.” Until then, be well. Adam

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APSF low-flow anesthesia education

Become a low-flow anesthesia expert and earn CME’s!
Complete this hands-on low-flow anesthesia education learning module (if you haven’t done so already).  Earn CMEs through

Low-Flow Anesthesia – Anesthesia Patient Safety Foundation
This APSF module will greatly assist you in becoming much more comfortable with the concepts of safe delivery of low-flow anesthesia. Low-flow anesthesia maintenance is the single best clinical practice for us to make the most of our contribution toward protecting our planet.

Please complete this excellent activity and gradually apply what you have learned to your practice.

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Rapidly Increase MAC Using The “Hands’On” Technique