(Volatile Induction and Maintenance Anesthesia) How...

VIMA(Volatile Induction and Maintenance Anesthesia)

How and Why

James H. Philip M.E.(E), M.D.

© Copyright 1995 - 2007, James H Philip, all rights reserved

VIMA(Volatile Induction and Maintenance Anesthesia)

How and Why

James H. Philip, M.E.(E.), M.D.Anesthesiologist and

Director of Bioengineering,Brigham and Women's Hospital

Associate Professor of Anaesthesia, Harvard Medical School

Medical Liaison, Partners Biomedical Engineering

Gas Man

Info:gasmanweb.com

I will u

se

Three unique uses for Sevoflurane

Almost uniqueSevoflurane SedationSevoflurane for a difficult airwaySevoflurane Vital Capacity Induction

Sevoflurane Sedation

2 L/min FGFSevoflurane 2%PO Oral Ibuprofen (Advil, Motrin) $0.50

It worksNo need for other drugs

IV Induction agent (Pent/Prop)OpioidMuscle relaxant (any NMB)Reversal agents for NMB

Why do VCI?

No relaxants No Propofol


No use


No use

No waste

InexpensiveSatisfying toPatientAnesthesiologistSurgeon

Why do VIMA?

Howto do

VolatileInduction

Premedication

None, typicallyAnything, as requiredTry talking, first

Sedation possibility

Propofol 10 mgBWH Pharmacy makes 10 mL syringes2 mL syringes would be better

Volatile Induction

Fast*Volatile agent alone,

with or without nitrous oxideDeep breath

51 ± 4 seconds, 1 - 4 breaths39 ± 3 seconds, if 1 breath

* Philip BK, Lombard L, Calalang I, Philip J. Sevoflurane Vital Capacity Induction Compared with Propofol Intravenous Induction for AdultAmbulatory Anesthesia. Anesth & Analg 87:623-7, 1999.

2 minute Preparation

Volatile Prime for anesthesia circuit

Oxygen Prime for lungs

Mental Prime for patient

Volatile Prime GoalPrime the circuit with8% Sevoflurane66 - 75% N2O

Semi-Closed CircuitVolatile Prime8% Sevoflurane1 L / min O2

3 L / min N2OPrime for 2 minutesSame time as pre-oxygenation

Volatile PrimeRequired to provide

sudden, large, controlledincrease ininspired anesthetic concentration

Inspired Control by any means is OKNew machines and techniquesmay make this easier

How to do Volatile Prime

Volatile PrimeEmpty the circuitFGF = 0 - flows all offOpen relief (APL, pop-off) valveSqueeze bag to empty circuitAttach maskSeal mask

Glove, stopper, cork, plug, other

One way - seal mask with glove

Another way -seal mask and circuit with tight-

fiting occluder

Prime the CircuitEmpty the circuit firstFGF=0Attach maskSeal maskOpen APL valve fullyEmpty reservoir bag through APL

Prime the CircuitEmpty the circuit firstFGF=0Attach maskSeal mask with glove Open APL valve fullyEmpty reservoir bag through APL Let reservoir bag fill

Normal flow in breathing circuit

Flow goes forwardIn the direction of the valvesEmptying and filling reservoir bagand lungs,alternately

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Normal flow in the breathing circuit - Inspiration

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Normal flow in the breathing circuit - Expiration

Priming the Circuit

Flow goes backwardsBlocked by each valveFilling the reservoir

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Back-fill the breathing circuit (#1)

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Empty the reservoir bag (#1)

Squeeze

CO2

Ab-sorb-ant

Sampled

Exhaust

200 mL/min

Fresh

Fill the reservoir bag again (#2)

CO2

Ab-sorb-ant

Sampled

Exhaust

200 mL/min

Fresh

Empty the reservoir bag (#2)

CO2

Ab-sorb-ant

Sampled

Exhaust

200 mL/min

Fresh

Fill the reservoir bag again (#3)

CO2

Ab-sorb-ant

Sampled

Exhaust

200 mL/min

Fresh

Close the Exhaust Valve

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Empty reservoir bag (#3) and fill the inspired limb

Squeeze

Closed

Sampled

CO2

Ab-sorb-ant

200 mL/min

Fresh

Empty reservoir bag (#3) and fill the inspired limb

Squeeze

ExhaustClosed

Sampled

CO2

Ab-sorb-ant

200 mL/min

Fresh

Open the Exhaust - Fill the Expired Limb (#3)

Release

Sampled

Exhaust

CO2

Ab-sorb-ant

200 mL/min

Fresh

Remove Glove, Apply mask to patient (#4)

Release

Patient

Gas Monitor shows Circuit is Ready

Circuit is ready

Gas Monitor shows Circuit is Ready

Circuit is ready

After third bag-fill

Here is how to test when ckt is ready

Sampleto gas monitor

Sample from Reservoir Bag Attachment

Bag #


Volatile Prime for anesthesia circuit √

Oxygen Prime for lungs


While priming circuitPreoxygenate

Simple Circuit

Simple parts

Simple parts

Reservoir bag(with cut end)

15-22mm adapter

Sampling(oxygenating)

Elbow

Oxygensource

Mask

Option in some countries:SiBI Connector

Skip the next 4 slides to skip this section

Facilitates pre-oxygenation during circuit prime

We have some at BWH

SiBI(TM) Connector

SiBI Close-up

November 4, 2001 SiBI

South Lake Regional Hosp Ont 01/22/02

Peak Inspired Agent MonitoringSome monitors report Inspired = Peak InspiredThis is a problem if Mean and Peak differMean is representative of what affects uptakeGE-Datex-Ohmeda ADU puts FGF after Insp ValveThis makes Mean and Peak differ greatly

CO2

Ab-sorb-ant

Most ADS

Normal Breathing Circuit FGF path

I

E

CO2

Ab-sorb-ant

ADU

GE “ADU” FGF path

I,E

GE ADU wave data

SiBI -> Ckt

InspExp

Exp

Insp

SiBI -> Ckt

InspExp

Exp

Insp

Mean Inspired = 2%, different from 7.1% peak

Anesthetizes like 2%, not 7%



Oxygen Prime for lungs √


Mental Prime PatientInstruct and practice VCVC = Vital Capacity breath

Breathe all the way out Take a deep breath inHold it inMaintain positive verbal contact

Create positive experiencethrough words and actions

2 minute Preparation is done


Oxygen Prime for lungs √

Mental Prime for patient √

Ready for Volatile Induction

VI - Volatile InductionSay and DoSay: “Exhale”Do: Switch to Sevoflurane maskSay: “Inhale and hold inspiration”Do: Maintain positive verbal contact Maintain high (7%) inspired sevoflurane conc.

> One Breath Induction

If patient breathes outInstruct patient to

take another deep breath and hold itTake another deep breath and hold itTake another deep breath and hold it

Data from BWH First Series

18 patients with perfect data for analysisIn first 20 seconds after VCISevoflurane %M SD

Inspired = 6.2 + 0.8Expired = 4.2 + 0.8

Nitrous OxideMean = 58 + 6

Most lost lash reflex in 1 breathSome required 2 breathsFew required 3 breaths

Anesthetize and Oxygenate togetherVCI Sevo 8% in Oxygen

Slightly slowerNo Second Gas EffectNo additional effect of N2O

Always quite adequateAllows same settings from VCI to airway securement (Tracheal Tube, LMA)

Volatile Induction Phase TwoDeepen Inhalation Anesthesia

After loss of consciousness in 1 minContinue induction with 8% SevoAssist or control ventilationPrepare to secure airway if desired

O2 + SevoSecure airway

LMA OK in 2 minutes ETT OK in 3 - 5 minutes (no relaxant)

Produce apnea before removing mask

Hyperventilate to apnea

Avoid losing anesthetic fromlungsbloodbrain

Or, keep anesthesia light

Natural airway orMinor airway interventions

Oropharyngeal airwayNasopharyngeal airway

Deepen anesthesia before incision

Monitor

CarefullyOftenBP q 1 minute (for a while)Always “automatic”

Induction is complete

Maintenance begins

VM - Volatile Maintenance Anesthesia

We have always done thisMaintain desired anesthetic depthDecrease fresh gas flows to save costIncrease vaporizer settingMaintain previous expired anesthetic conc.Maintain previous anesthetic depthIncrease and decrease depth as requiredReact or anticipate


Depth = Constant + Adjust as requiredThree anesthetic conditions

Constant IncreaseDecrease


Depth = Constant + Adjust as requiredThree anesthetic conditions

Constant Increase Vaporizer to Max = 8%Decrease Vaporizer off = 0%Increase FGF if required

Readjust vaporizer to near prior setting

Overpressure

Underpressure

Up and downusing Overpressureand Underpressure

2

4

6

8

10

0-10 -20 -30

time (minutes)

I

E

For short cases, remember

Awakening begins just after inductionDon’t be afraid to turn the vaporizer offBring expired concentration down to 1.3 MACKeep expired at 0.7 MAC near the very end

Prepare for recovery - always

Recovery begins with wake upRecovery ends with

patient back to normalNormal means normal -

Patient is satisfiedAnesthesiologist is satisfied Surgeon is satisfied

Volatile EmergenceVolatile emergence is smooth

Create and maintain zero (0.0) inspired agent concentrationEmpty the Reservoir Bag, Flush O2, High FGF

Ventilate anesthetic out of lungsMinute ventilation > 4 L/minpETCO2 around 36 mmHg

FGF is low

Increase FGF

Problems occur with wake up if FGF or Ventilation is low

Poor circuitwash out;FGF too low

Ventilation is lowProblems occur with wake up if FGF or Ventilation is low

Poor lung wash out.Ventilation is too low

Better wake up w experience

Usually, wake up is better

Low inspiredLow expired

1.0

.2

.4

.6

.8

0.00 Minutes of administration 30

A/I

Data from Yasuda & Eger, 1991

Zerothane 0.88

0.71

0.56

0.83

Volatile InductionDes

Sev

Iso

Hal FE

F I

0 Minutes of discontinuation 30

A/I0 Zerothane

Alveolar response to inspired = 0

0.12

0.29

0.44

0.17

0.0

.8

.6

.4

.2

1.0

FE

FE0

After a long anesthetic

Volatile Emergence

DesSev

Iso

Hal


A/I0 Zerothane


0.12

0.29

0.44

0.17

0.0

.8

.6

.4

.2

1.0

FE

FE0


0.33 MACAwake

Volatile Emergence

DesSev

Iso

Hal


A/I0 Zerothane


0.12

0.29

0.44

0.17

0.0

.8

.6

.4

.2

1.0

FE

FE0


0.20MACclimb to strether (approx)

Volatile Emergence

DesSev

Iso

Hal

0.33 MACAwake

No need forIV Induction agentOpioidMuscle relaxant (NMB)Reversal agents for NMBOther drugsComplications

Avoid Side EffectsAvoid Costs

Clinical Benefits of VIMA

VIMA providesDeep anesthesia from beginning to endNo additional drugs for intubationNo additional drugs for intra-op painRapid awakening and return to normalPost-op pain requires local anesthesia infiltration

anesthesia and post-op analgesic

How toavoid slow wake ups

FGF is low

Increase FGF

Problems occur with wake up if FGF or Ventilation is low

Poor circuitwash out;FGF too low

Ventilation is lowProblems occur with wake up if FGF or Ventilation is low

Poor lung wash out.Ventilation is too low



Low inspiredLow expired

SummaryVIMA is Volatile Induction and Maintenance Anesthesia.VIMA is an acceptable equivalent alternative to IV plus Volatile combinations.VIMA preparation requires 2 minutes for circuit anesthetic prime, lung oxygen prime, and brain psychological prime.VIMA Sevoflurane induction is faster than IV Propofol (51 ± 4 sec vs. 81 ± 12 sec).VIMA wake up is as fast and uncomplicated as Propofol induction and VM anesthesia.

Thank you

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