A Nest General

8/12/2019 A Nest General

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Definition of anesthesia

It is a reversable blocking of pain feeling in

whole body or in a part of it using

pharmacology or other methods


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Anesthesia- division

Local-regional anesthesia, patient isconscious or sedated

General-anesthesia interact with wholebody, function of central nervous system isdepressed:

Intravenous

Inhalation (volatile)Combined, balanced


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TIVA

Total

Intra

Venous

Anaesthesia


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VIMA

Volatile

Inductionand

Maintain

Anaesthesia


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Parts of general anesthesia

Hypnosis- pharmacological sleep,

reversable lack of consciousness

Analgesia-pain management Areflexio-lack of reflexes

Relaxatio musculorum- muscle relaxation,

pharmacological reversable neuromuscularblockade


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Parts of general anesthesia must be

in balance

Hypnosis(anesthesia) Analgesia

Lack of reflexes (muscle relaxation)


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General anesthesia

features

LackLackofofreflexesreflexes

3

LackLackofofconsciousnessconsciousness

11

PainPainmanagementmanagement

22NeuromuscularNeuromuscularblockadeblockade

44


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Stages of general anesthesia

Stadium analgesiae (analgesia and

sedation stage)

Stadium excitationis (excitation stage) Stadium anaesthesiae chirurgicae

(anesthesia for surgery)

Stadium paralysis respirationis(intoxication, respiratory arrest)


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II. Excitation stage

Possible uncontrolled movements,

vomitings

Increase in respiratory rate


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IV. intoxication, overdosing

Respiratory arrest

If anesthesia not discontinued possible

cardiac arrest


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EstimationEstimationofofthetheriskriskofofanesthesiaanesthesia((AmericanAmerican

SocietySocietyofofAnesthesiologistsAnesthesiologistsscalescale))

ASA 1ASA 1::healthyhealthypatientpatient..

ASA 2ASA 2:: patientpatient withwith stablestable,, treatedtreated illnessillness likelike arterialarterial

hypertensionhypertension,, diabetesdiabetes melitusmelitus,, asthmaasthma bronchialebronchiale,,

obesityobesity

ASA 3ASA 3:: patientpatient withwith systemicsystemic illnessillness decreasingdecreasing

suffitiencysuffitiency likelikeheartheartilnessilness,,latelateinfarctinfarct

ASA 4ASA 4:: patientpatient withwith seriousserious illnessillness influencinginfluencing hishis statestate

likelike renalrenal insuficiencyinsuficiency,, unstableunstable hypertensionhypertension,,

circulatorycirculatoryinsuficiencyinsuficiency

ASA 5ASA 5::patientpatientininlifelifetreateningtreateningillnessillness ASA 6ASA 6::brainbraindeathdeath--potentialpotential organ donororgan donor


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PremedicationPremedication

MainMainreasonsreasonsforforpremedicationpremedication::

AnxiolysisAnxiolysis--lacklackofofthreatthreat

SedationSedationcalmingcalmingdowndown

AmnesiaAmnesialacklackofofmemoriesmemoriesofof

perioperativeperioperativeperiodperiod


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M ethods of general anesthesia

OPEN

SEMIOPEN

SEMICLOSED

CLOSED


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M ETH ODS OF GENERAL ANESTH ESI A

OPEN- old

SEMIOPEN used mostly in pediatric anesthesia

SEMICLOSED- most common

CLOSED- modern anesthesia


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M ethods of general anesthesia

CIRCLE SYSTEMCI RCLE SYSTEM

*HIGHHIGH--FLOWFLOW

FRESH GAS FLOW

3 l/min.*LOWLOW--FLOWFLOW

FGF ok. 1l/min.

*MINIMALMINIMAL--FLOWFLOW

FGF ok. 0,5 l/min.


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Stages of general anesthesia

Introduction to anesthesia (induction)

Maintaining of anesthesia (conduction)

Recovery from anesthesia


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Anesthesia agents1. Inhalation anesthetics (volatile anesthetics)

- gases : N2O, xenon

- Fluids (vaporisers)

2. Intravenous anesthetics

- Barbiturans : thiopental

- Others : propofol, etomidat3. Pain killers

- Opioids: fentanyl, sufentanil, alfentanil, remifentanil, morphine

- Non Steroid Anti Inflamatory Drugs: ketonal, paracetamol

4. Relaxants

- Depolarising : succinilcholine

- Non depolarising : atracurium, cisatracurium, vecuronium, rocuronium

5. adiuvants-benzodiazepins: midasolam, diazepam


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Volatile

vs

intravenous anesthesia


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Mechanism of action of

inhaled anesthetics

Reaction depends on concentration. This depends

on alveolar (first compartment), blood and brain

(central compartment) concentration , (third

compartment- other tissue like muscles, fat-

accumulation effect):

Minute ventilation

Lung blood perfusion

Solubility in tissues


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MAC-minimal alveolar

concentration

Concentration in which 50% of anesthetised

patients do not react on skin incision

Corelation with solubility in fat tissue The lower MAC is the higher strenght of

action is


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Inhalation agents


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Division of inhalation agents

1. Gases:

N2O old, weak, used as adiuvant

Xenon lately introduced

2. Vapors (fluids):

Halothan

Enfluran

Isofluran

Sevofluran

Desfluran


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Features of ideal volatile

anesthetic

Not disturbing smell

Fast acting, titrable

Low solubility in blood- fast transport to brain

Stable when stored, not reacting with otherchemicals

Non- flamable, non- explosive

Low methabolism in body, fast elimination, noaccumulative effect

No depressing effect on circulatory and respiratorysystems


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Nitrous oxide, laughing gas

Old

Weak

Used as adiuvant

Will be removed form medical use up to

2010- destroyes ozone lawyer


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Halothan

Used for many years with good effect

First non-flamable volatile fluid anesthetic

MAC high

Depression of circulatory system

May destroy liver

Now-a-days used only in pediatricanesthesia


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Isofluran

Disturbing smell

May interact with heart contractivity

Increases relaxation of muscles


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Desfluran

Very disturbing smell- can not be used forVIMA

Is not methabolised Very fast acting

May be used for one-day surgery

Expensive, difficult to store (boiling temp.

about 20 C) Modern and widelly used


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Intravenous anesthesia


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TCI is an infusion system which allows the

anaesthetist to select the target blood

concentration required for a particular

effect

and then to control depth of anaesthesia

by adjusting the requested target

concentration

Defining TCI

When applied to anaesthesia


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What is TCI?

Instead of setting ml/h or a dose rate (mg/kg/h),

the pump can be programmed to target a

required blood concentration.

Effect site concentration targeting is nowincluded for certain pharmacokinetic models.

The pump will automatically calculate how

much is needed as induction and maintenance to

maintain that concentration.


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Intravenous anesthetics


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Thiopental

Old, one of the first used intravenous

anesthetics

Depressing effect on circulatory system May be used in patients with ASA 1


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Etomidat

Has no depressing effect on circulatory

system- may be used in patients with

circulatory insufficiency May give musle contractions

Depressing effect on epirenals function

Can not be given in repeated bolus nor

continuous infusion


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Propofol

Very good anesthetic for induction and

maintaince of anesthesia with no

accumulation effect

Titrable May be used in short procedures titrated

do not effect circulatory and respiratory

system in important manner

Good for sedation, brain protecting effect

May be used in TCI


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Pain killers


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Opioids

fentanyl, alfentanil, sufentanil, remifentanil

May be used for induction and maintain of

anesthesia in repeated bolus or continuous

infusion technique

Sedative effect

In high doses may be used alone for so called

opioid anesthesia- formerly used in

cardioanesthesia- very stable circulatory effect


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Compications of use

Respiratory depression !!!!

Muscle rigidity in high doses

Post-Operative Nausea and Vomitings Accumulation effect after prolonged

administration (except for remifentanil)


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Remifentanil modern opioid

analgesic

T1/23-5 min !!

Methabolised by non-specific tissue

esterases- methabolism is not altered byrenal or liver function

No accumulation effect after prolonged

infusion !!


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NSAID

Used as adiuvants in short, not very painful

procedures

Used for preemptive analgesia reduction of consumption of opioids by

blocking COX


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Benzodiazepiny

Used in anesthesia:

Diazepam

Midazolam Used as adiuvants for premedication


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Muscle relaxants


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Nondepolarising agents

-d-tubocurine oldest deliverate of curarine

-alcuronium

-pancuronium cheap and still used

-pipercuronium-vercuronium

-atracurium

-cisatracurium

-mivacurium-rocuronium


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Division of nondepolarising

relaxants due to

Chemical structure:

Miwakurium(Mivacron)Cisatrakurium(Nimbex)

Atrakurium(Trakurium)

Pankuronium(Pavulon)Pipekuronium(Arduan)Rapakuronium (Raplon)Rokuronium(Esmeron)

Wekuronium(Norcuron)

Benzylizochinolons:Aminosteroids:


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Division of nondepolarising

relaxants due to

time of action:

Short acting < 3 min: still searching

Midle time 60 min: pancuronium,pipecuronium


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Atracurium

Elimination non-enzymatic, independent of

renal and liver function, Hoffman

elimination- hydrolisis Releases histamine

Acts about 30 min


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Cisatracurium

One of stereoisomers of atracurium,

Do not release histamine

Acts about 60 min


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Rocuronium

Fast acting- time to 100% supresion 60 sec.

Do not release histamine

Acts about 60 min Is methabolised in liver- disfunction of liver

may alter elimination


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Reverse of neuromuscular blockade

Neostigmine, piridostigmine- blockers of

acetylocholinesterase

Must be given toghether with atropine toavoid bradycardia caused by activation of

perisympatic system


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Depolarising agents

Only one:chlorsuccinilocholine

- It is methabolised by pseudocholinesterase

- Causes many complications, has many

contraindications

- Indications:Rapid sequence induction: full stomach, suspected difficult

intubation because it acts very fast < 30 seconds and short < 3min


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Monitoring during generalanesthesia


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Obligatory

Clinical observation

Circulatory system function: ECG, blood

pressure - Non-Invasive-Blood Pressure Respiratory function: SpO2(pulsoxymetry),

EtCO2

Neuromuscular function- ie accelerometry

TOF Guard


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Additional- advanced

Invasive Blood Pressure

Haemodynamic monitoring ie Doppler

transesophageal probe EEG monitoring for deepness of anesthesia

ie BIS (Bispectral Index), AEP - Auditory

Evoced Potentials, Entropy


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Complications of general

anesthesia

Respiratory: residual relaxants/opioids

action

Circulatory Neurological: residual anesthetics/opioids

action

Post-Operative Nausea and Vomitings


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Mortality connected with anesthesia

0,050,05--4/10000 GA4/10000 GA

22--16 %16 %ofofsurgicalsurgicalpatientspatients

80 %80 %isiscausedcausedbybyhumanhumanmistakemistake


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Other causes of mortality and morbidity

AnoxiaAnoxia

HaemodynamicHaemodynamicinstabilityinstability

AspirationAspiration

ToxityToxityofofdrugsdrugsmostlymostlyinhalationinhalation

agentsagents

AnaphylaxiaAnaphylaxiaandanddrugdruginterationsinterations


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AIRWAY MANAGEMENTAIRWAY MANAGEMENT

Respir ator y Distr ess vs. Respir ator y F ail ur eRespir ator y D istr ess vs. Respir ator y F ail ur e

DistressDistress

--Increased work of breathingIncreased work of breathing--RelativeRelativehypoxia/hypoxia/hypercapneahypercapnea

--CompensatingCompensating

FailureFailure

--Increased work of breathingIncreased work of breathing--ProfoundProfoundhypoxia/hypoxia/hypercapneahypercapnea

--DecompensatingDecompensating

Its a constant reassessment process


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Contraindications for face mask

and bag ventillation

Hernia hiatus aesophagus

gastric reflux

injury of face or neck brochial-esophagaeal connection

injury of trachea cartiladges

full stomach patient, vomitings


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I ndications for ET

(endotracheal intubation)

Airway obstruction

Cardio Pulmonary Resuscitation

Artificial ventilation

Anesthesia

Brain injury, facial injury, facial burn,

airway burn


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Complications of E TInjuries:

-theeth injury, mouth injury

-laryngs rupture

-aspiration

-bleeding

oesophagus intubation

one bronchus intubation

Reactions: vomitings, coughing, apnea,laryngospasm, bradycardia, hypertension


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Alternative airway management

Laryngeal mask- for short, not major

operations ecxept for head and neck surgery

for elective surgery- patient must beprepared for anesthesia

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