Vl til I d ti dVolatile Induction and Maintenance · PDF file1 Vl til I d ti dVolatile...

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V l til I d ti dVolatile Induction and Maintenance Anesthesia

VIMAAndrius Macas

KaunasLithuania

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Classical situation in Classical situation in LithuaniaLithuania

Induction: IVMaintenance: IV+Inhal

Up to 95 percent of general anaesthesia cases with tracheal

intubation

Sevoflurane in clinical Sevoflurane in clinical practicepractice

VIMA - benefitVIMA benefit

Anest

IV+inhal

PS

thesia Time

VIMA

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VIMAA (new) concept in volatile

th ianesthesia

Less adjuvant medication = less side effectsControl on depth of anesthesiaControl on depth of anesthesiaRapid and good (quality) recovery

Sevoflurane:Sevoflurane:MetabolismMetabolismMetabolitesMetabolites

Metabolized 2-5 %⇒ fluorid ion, hexafluoro-izopropanol

Temperature dependent degradation on soda limeTemperature dependent degradation on soda lime⇒ Compound A (Compound B)

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Sevoflurane Sevoflurane in clinical practicein clinical practice

InductionInduction

What features make Sevoflurane suitable forWhat features make Sevoflurane suitable forInductionnon-irritating, pleasant odorlow - blood/gas - solubility ⇒ FA/FI

rapid, smoothinduction

Low incidence of side effects-cough, breath holding, laryngeal spasm-excitation-disrhythmia


MaintenanceMaintenanceWhat features make Sevoflurane suitable forWhat features make Sevoflurane suitable for

Maintenance:low - blood/gas – solubilityC-V stabilitydoes not effect breathing significantly

Benefits:Rapid adjustment of anesthesia depth ⇒ FD/FA

percentageCircuit (Mapleson D ⇔ re-breathing system)FGF

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MaintenanceMaintenance

Rapid change in depth of anesthesia (0.5 – 3%)4x

FD/FA (SEV) < FD/FA (ISO)

(Desflurane is even “faster“ agent but irritating and can cause tachycardia)


RecoveryRecoveryWhat features make Sevoflurane suitable forWhat features make Sevoflurane suitable for

“smooth and rapid” recovery:low - blood/gas – solubility does not effect breathing significantlylow oil/water solubility

Benefit:rapid recovery:rapid recovery:

time to eye opening ≈ 4 - 6 mintime to discharge ≈ 2-3 h

recovery does not depend on the duration of anesthesia (MAC-h)

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VIMA: Volatile Induction and Maintenance of AnesthesiaVIMA: Volatile Induction and Maintenance of Anesthesia

VIMA benefit = use of single drug⊗ hypnosis, analgesia, relaxation⊗ i ll h f th i⊗ in all phases of anesthesia

VIMA: Anaesthesia simulation (scenario)

What are the purposes:What are the purposes:• Overpressure sevoflurane induction• Tidal capacity sevoflurane induction

• Use the sevoflurane different as halothane - take the advantage of sevoflurane

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Anesthesia Simulator Inhalation anesthesia

MD opinion (based on halothane)MD opinion (based on halothane)Advantage: easy maintenance, one agentDisadvantage: difficult induction, concentration depending side effect

Consequence: IV inductionIV induction

Goal: Use the sevoflurane different from halothane - take the advantage

Induction – “conventional”

Step by stepStep by stepStarting with low conc. and increasing Fd

FGF - constantOutcome: slow induction (potential complication at intubation)

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Options to perform “VIMA” induction:

“Vital capacity”

“Overpressure”

“Vital capacity” induction:

Options to perform induction (1)

Vital capacity induction:Fulfill the system with 8% SevoraneMasc on the faceAsk for deep exhale and after that deep inhaleThe patient should keep the air in as long as he/she canAsleeps after the 2-3 breath

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Induction

OverpressureOverpressureFGF: high volumeStart with Fd max, conc.8Fulfill the system with 8% SevoraneDeep breath countinuesDeep breath, countinues Result: Rapid induction

Over-pressure induction

How to prepare the patient ?How to prepare the patient ?Verbal contactWhat to do

Deep exhale → mask →deep inhale( →keep the air in)Finding

The odor of Sevo – not irritating Sleepy → continue to breath deeppy p

Monitoring Mistake: not cooperating patientConsequence: drag on induction

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How to prepare the anesthesia machineHow to prepare the anesthesia machine (AM)Fill up the AM with anesthetic

High flow 8-10 l/minO2 or O2/N2O = 1:1Sevoflurane vaporizer: 8 %Period : min. 40-45 secEmpty the balloon 2 or more time

Mistake: incorrect fill upConsequence: drag on induction


Start the anesthesiaStart the anesthesiaRepeat the patient instructionDeep exhale → mask →beep inhale →keep the air inPositive communication with the patientCheck the depth of anesthesia: monitor + clinical signs (eyelash reflex)signs (eyelash reflex)

Mistake: mask removalConsequence: slow inductionVein puncture: large vein, no reaction to pain.

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Increase the depth of anesthesia (phase)Increase the depth of anesthesia (phase)Excitation period (45-60 sec):

involuntary movementincrease on HR, irregular breathing etc.

Surgical phase anesthesia (90) –intub.150 )sec)

Norm HR, breathing rate ↓, regular breath etcAlv conc.: 3%


IntubationIntubationEasy approachModerate increase in hart rate, and BP

Mistake: early attempt to intubateConsequence:Consequence:

Cough, trismus,Inpossible to intubate

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Maintenance of anesthesia (low flow)Maintenance of anesthesia (low flow)FGF 1-2 lit/minO2/N2O ratio 50: 50%F dialed: ~ 2,2-2,6%

Mistake: high drug uptakeg g pConsequence: overdose

Why should we?

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The features of Sevoflurane give the benefit

Why should we?

The features of Sevoflurane give the benefit of flexibilitySevoflurane anesthesia decreases the need of opioids

Quicker recoveryThe recovery – short term - is similar to propofolThe recovery short term is similar to propofolRecovery – longer term – exceeds the propofol recovery

Isoflurane is too slow desflurane is

Why not others?

Isoflurane is too slow, desflurane is irritatingPropofol has only hypnotic effect and the decrease of opioids is questionable. Increasing the dosage of propofol increases the side effect of the drugincreases the side effect of the drug, like:

HypotensionDelay in recovery

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In practice

When it is required to increase theWhen it is required to increase the depth of anesthesia it is necessary to:Increase the FGF to 6 lit/minIncrease the Fd to 8%

Period 2-3 min

In practiceInduction 1

MAC LMA (laryngeal masc anesthesia) = MACMAC LMA (laryngeal masc anesthesia) = MAC surgery = Fa 2%MAC Intubation

(without opioid and relaxant) = Fa 4,75%It is possible after 4-5 minp

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In practiceInduction 2

Fi 8% gives the Fa 4 5% within 1 minFi 8% gives the Fa 4-5% within 1 minAlveolar/brain half time = 3.5 minWithin 30-60 sec the concentration in the brain will achieve 0.5%Patient becomes unconscious=MACPatient becomes unconscious=MAC awake

In practice. Maintenance 1

“just enough to do the job”

Balance anesthesia offers an adequateBalance anesthesia offers an adequate analgesia with:

NSAIDLocal anesthetic

Minimal use of opioids

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Post inductionPost inductionDecrease of FGF – step by stepDecrease of vapor conc. Fd – even to 0%Maintenance 1.3 – 1.5 MACAt this concentration in quite big amount of cases it is not necessary to use opioids during surgical procedures



The Sevoflurane by its futures - the lowThe Sevoflurane by its futures - the low solubility and non irritating – ensure the immediately respond (compared with highly soluble and irritating anesth. drugs)The bolus does not effect the recoverySevoflurane gives the opportunity to performSevoflurane gives the opportunity to perform dynamic anesthesia and decreases the quantity of opioidsRecovery focused anesthesia

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VIMA in Lithuania

How many?How many?

VIMA in Lithuania

How many?How many?Not so many. Up to 5-10 percent in different settings

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VIMA in Lithuania


Why?

VIMA in Lithuania


Why?We are used to IV induction

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VIMA in Lithuania

Should we increase?Should we increase?

VIMA in Lithuania

Should we increase?Should we increase?Yes, we should.

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VIMA in Lithuania


Should we improve VIMA technique?

VIMA in Lithuania


Should we improve VIMA technique?Yes. Because all of us say “we do VIMA”, but:Some of us do “ViMA”, Some – “V(i+IV)MA”,Some - “V(i+IV)x(MI+MIV)A”

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Kaunas University of Medicine:

Anaesthesiology clinicMedical simulation center

Initiated in 2009Established in January 2010 Fi t J 2010First courses – January 2010First foreign group – April 2010

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