General anesthesiaGeneral anesthesia

MethodsMethods

Definition and goalDefinition and goalDefinition:Definition: A state where the patientA state where the patient

does not respond to painful stimulidoes not respond to painful stimuli does not recall these stimulidoes not recall these stimuli

responsesresponses:: somaticsomatic vegetativevegetative control of anaesthesiacontrol of anaesthesia emotional/behaviouralemotional/behavioural

Main goals:Main goals: total total abolitabolition ion of of painpain suppression of harmful suppression of harmful reflexesreflexes relaxationrelaxation of striated muscles of striated muscles (body cavity or extremities) (body cavity or extremities)

Modes of general anaesthesiaModes of general anaesthesia

Main components: Main components: analgesiaanalgesia--amnesiaamnesia--unconsciousnessunconsciousness((hypnosishypnosis) – attenuation of ) – attenuation of

unwanted (harmful) vegetatív unwanted (harmful) vegetatív reflexesreflexes – immobility (muscle – immobility (muscle relaxationrelaxation).).

Main types of anaesthesia: Main types of anaesthesia: mono-anaesthesia:mono-anaesthesia:

single agent (e.g. aether) in high doses =single agent (e.g. aether) in high doses =overdosing of the agent to achieve certain special goals by side-effects of overdosing of the agent to achieve certain special goals by side-effects of

the drug (eg. muscle relaxation by high doses of aether)the drug (eg. muscle relaxation by high doses of aether) combined combined general general anaesthesiaanaesthesia: all desired effects achieved : all desired effects achieved

with appropriate doses of specific agents ( balanced with appropriate doses of specific agents ( balanced anaesthesia)anaesthesia)

side-effects avoided or diminished side-effects avoided or diminished proper management of anaesthesiaproper management of anaesthesia accommodation to individual needsaccommodation to individual needs accommodation to actual extent of variable intra-operative painaccommodation to actual extent of variable intra-operative pain

Stages of general anaesthesia Stages of general anaesthesia with ether with ether according to Guedelaccording to Guedel

I. Stadium analgesiaeI. Stadium analgesiae

II. Stadium excitationisII. Stadium excitationis

III. Stadium tolerantiaeIII. Stadium tolerantiae III/1-2-3-III/1-2-3-4.4.

IV. Stadium asphyxiaeIV. Stadium asphyxiae

Basics of classification:Basics of classification: consciousnessconsciousness ocular signs (pupilla)ocular signs (pupilla) breathing patternbreathing pattern vegetative signs (pulse)vegetative signs (pulse) muscle tonemuscle tone

StádiumStádium Conscious- ness

Br.

pupilla eyelid cornea secret. light gag vomit str. abd. smooth

I. I. 1.

Anal- 2. gesia 3.

II.II.excitaton

III. III. 1.1.

Tole- 2.2.

rance 3.3.

4.4.

IV.IV.As- phyxia

ReflexesMuscle tone

How can we get the anesthestics to How can we get the anesthestics to the place of their actionthe place of their action??

To the receptors and structions of the CNS peripheric receptors (e.g. neuromuscular junction)

It is always the blood circulation the anesthetics are transported by

Ways to the blood streem: GI system (intestinal capillary-portal vene – VCI- RA-RV-

lungs – LA – LV – arterial system) Mucous membranes (capillaries-venes-RA-RV-lungs – LA

– LV – arterial system) Injection into periferic tissues → capillaries…..

(i.c., s.c., i.m. application) Intravenous injection

(v.cava-RA-RV-lungs-LA-LV-arteries)

Inhalation (lung capillaries-v.pulm.-LA-LV-arteries)

General anaesthesiaGeneral anaesthesia Cannot be deCannot be desscribed by a simple and single cribed by a simple and single

processprocess - - at least two fundamental processes: at least two fundamental processes: inhibition of painful stimuliinhibition of painful stimuli andand loss of consciousness loss of consciousness

Loss of consiousness is Loss of consiousness is achievedachieved by hypnotics by hypnotics Pain inhibition is Pain inhibition is achievedachieved by analgetics by analgetics

(opioids)(opioids) ThTheseese two different effects are closely related, two different effects are closely related,

the relation is continuous: the relation is continuous: very high dose of a hypnotic produces anti-very high dose of a hypnotic produces anti-

nociception,nociception, very high dose of an analgetic (opioid) produces very high dose of an analgetic (opioid) produces

unconsciousnessunconsciousness

Preparation before anesthesiaPreparation before anesthesiaBefore the patient arrives

Preparation and check of the equipment (e.g. suction, monitors, infusion, intubation, airway

maintenance equipment)

Check up: anesthesia machine, gas supply

Preparation of medicaments

After arrival of the patient

Greeting of patient, documentation checkup, anesthesia sheet

Monitors, registration of starting values

Venous access

Parts of general anesthesiaParts of general anesthesia Induction

From the start of the induction agent to the point when the patient is ready for the operation

MaintenanceMaintenance of the necessary depth of

anesthesia during operation and continuous control of the vital functions of the patient (values, tendencies, correction as necessary)

End (arousal) and recovery On the operating table Delayed– complete arousal later in the RR or

ICU

Drugs for general anaesthesiaDrugs for general anaesthesia Drugs for preoperative Drugs for preoperative preparationpreparation

sedatives, analgesics, vegetative (parasympatholytic) drugssedatives, analgesics, vegetative (parasympatholytic) drugs drugs for drugs for inductioninduction of anaesthesia of anaesthesia

short acting iv. short acting iv. aanaestheticsnaesthetics, inhalation agent(s), inhalation agent(s) maintenancemaintenance of anaesthesia of anaesthesia

intravenous intravenous oror/and /and volatile anaesthetics volatile anaesthetics + + supplementary drugssupplementary drugs

analgesics, vegetative stabilizing drugs, additives, analgesics, vegetative stabilizing drugs, additives, potentiating agents and other drugspotentiating agents and other drugs

drugs fordrugs for aawakeningwakening antagonists: antagonists: ((opioids, benzodiazepinesopioids, benzodiazepines), antidote of muscle ), antidote of muscle

relaxantsrelaxants

Decision influenced by:Decision influenced by: Patient’sPatient’s demands demands

Condition of the patient (hypCondition of the patient (hyperertension, cardiac failuretension, cardiac failure, …, …)) Circumstances of treatment (emergencyCircumstances of treatment (emergency or elective or elective situations) situations)

SurgicalSurgical aspects aspects type of surgerytype of surgery (e.g. dental-, dento-alveolar-, maxillo-facial (e.g. dental-, dento-alveolar-, maxillo-facial

surgery) surgery) region of procedureregion of procedure (intraoral, extraoral…) (intraoral, extraoral…) length of procedurelength of procedure special requirements (special requirements (e.g. controlled e.g. controlled hypotension needed)hypotension needed)

PPersonal ersonal experienceexperience of anaesthesiologist of anaesthesiologist Available circumstancesAvailable circumstances

Which method of anaesthesia?Which method of anaesthesia?

Intravenous anesthesiaIntravenous anesthesia

Bolus administrationBolus administration Continuous infusion (pump)Continuous infusion (pump)

Advantages Drawbacks•Easy, quick administration•Known dose•Does not depend on breathing•Combination of different agents possible•No pollution

•Once given, the dose can not be reduced

•Elimination depends on organ function/enzymes

•Allergy - more often

IV bolus administrationIV bolus administration

effective concentration

concentration

First dose Second dose

MethodsMethods• Total IntraVenous Anesthesia (TIVA)

Intravenous induction and maintenance Intravenous induction and maintenance (infusion pump) VentilationVentilation: oxygen – air mixture: oxygen – air mixture

• IntraVenous Anesthesia (IVA) – e.g. NLAII! Intravenous induction and mainetnance Intravenous induction and mainetnance (continuous or bolus) Ventilation: oxygen – nitrous oxide

• Inhalation anesthesia anesthesia Induction can be IV (adults), maintenance by inhalationInduction can be IV (adults), maintenance by inhalation VIMA: Volatile Induction and Maintenance of Anaesthesia: Volatile Induction and Maintenance of Anaesthesia

• Balanced anesthesia anesthesia Combination of intravenous and inhalational method Combination of intravenous and inhalational method (in a broader (in a broader

concept combination of more thasn one methods – e.g. GA + regional anesth.)concept combination of more thasn one methods – e.g. GA + regional anesth.)

Inhalation anesthesiaInhalation anesthesia

ProPro

Easy continuous administration

Easy modulation of blood concentration

Elimination through the lungs

Allergy rate low

ContraContra

Needs specific vaporizers

Induction can be slow, unpleasant

Pollution

Price?

InductionInduction Venous access, documentation, monitoring Medical preparation Preoxigenation Hypnosis/narcosis (Muscle relaxation) Securing of the airways: endotracheal intubation,

laryngeal mask,… Attachment of special equipment,… (+extra IV

access?) invasive monitoring? (Bladder catheter, CVC…) Positioning of the patient, stabilization Deepening of anesthesia, analgesia

Induction IIInduction II Medical preparation (coinduction)

E.g. Fentanyl + Midazolam (Earlier: Fentanyl + DHBP – NLA)

Intravenous induction – („falling asleep”) Bolus injection

eg. Thiopenthal, Propofol, Ethomidate,(Ketamin) + relaxant

Continuous administration by infusion pump

Inhalation induction Quick technique – (single breath method – a total vital

capacity breath after filling up of the system) Continuous inhalation (children)

Intravenous induction agents I. Intravenous induction agents I. Intravenous barbiturates

methohexital, thiopenthal, thiobutabarbitalmethohexital, thiopenthal, thiobutabarbital• Only for single induction or short IV anesthesia!Only for single induction or short IV anesthesia! • Quick action, redistribution, tendence to accumulationQuick action, redistribution, tendence to accumulation

Velocity of the injection influences the actionVelocity of the injection influences the action

• Negative inotropy + vasodilationNegative inotropy + vasodilationReduced cerebral metabolism and oxygen consumptionReduced cerebral metabolism and oxygen consumptionTissue damage!Tissue damage!

• Dose depends on the ageDose depends on the age, general state, previous medication , general state, previous medication (DHBP or Midazolam, Fentanyl reduce the dose)(DHBP or Midazolam, Fentanyl reduce the dose)

(1)-3-5 mg/kg diluted (1-2.5%), according to the effect!(1)-3-5 mg/kg diluted (1-2.5%), according to the effect!Slow injection until the eyelid reflex disappeares!Slow injection until the eyelid reflex disappeares!

• Contraindication:Contraindication: porphyria, lack of good veins, porphyria, lack of good veins, ventilation difficulties, circulatory insufficiency ventilation difficulties, circulatory insufficiency

Intravenous induction agents II.Intravenous induction agents II. EthomidateEthomidate

Only for induction (single dose) – short actionOnly for induction (single dose) – short action DoseDose: 0.15-0.3 mg/kg of the 0.2% solution (10 ml=20 mg): 0.15-0.3 mg/kg of the 0.2% solution (10 ml=20 mg) Circulatory effects less than with other agents Circulatory effects less than with other agents (for high risk cardiovascular for high risk cardiovascular

patients). Spontaneous twiching possiblepatients). Spontaneous twiching possible Adrenal depression!Adrenal depression!

Ketamine (S+ Ketamine)Ketamine (S+ Ketamine) „„Dissociative anesthesia”, hallucinogenic effects, Dissociative anesthesia”, hallucinogenic effects, analgesiaanalgesia DoseDose: 1-2 mg/kg IV (3-4 mg/kg IM), for repetition or sedation 0.1-1 mg/kg: 1-2 mg/kg IV (3-4 mg/kg IM), for repetition or sedation 0.1-1 mg/kg Good for: children, combinations - hypotensive patientsGood for: children, combinations - hypotensive patients Elevates the BP, intracranial pressure, intraocular pressure, blood Elevates the BP, intracranial pressure, intraocular pressure, blood

concentrastions of catehcolamines! Reflex sensitivity elevatedconcentrastions of catehcolamines! Reflex sensitivity elevated

PropofolPropofol Other agents for Other agents for IV induction or coinduction: IV induction or coinduction:

Midazolam Opioids ….

Clonidin

Intravenous induction agents III. Intravenous induction agents III. Anesthesia indction (and maintenance) withAnesthesia indction (and maintenance) with

Propofol Propofol (Diprivan)Characteristic: Quick and short action, easy control of anesthesia depth Reduces BP (cardiodepressive, vasodilatative) Venous irritation

Bolus-administration: Sleep dose: 2 mg/kg (slowly), repeated dose: 0.5-1 mg/kgSleep dose: 2 mg/kg (slowly), repeated dose: 0.5-1 mg/kg

Continuous administration With infusion pump 4-12 mg/kg/hourWith infusion pump 4-12 mg/kg/hour TCI („Target Controlled Infusion”) TCI („Target Controlled Infusion”) ––

(target concentration 3-5 (target concentration 3-5 g/ml)g/ml)

Typical coinduction methodTypical coinduction method

IV IV MidazolamMidazolam ( (Dormicum) 0.1-(0.2) mg/kg) 0.1-(0.2) mg/kg IV IV Fentanyl Fentanyl 1-1.5 g/kg Oxygen inhalation IV induction (Thiopenthal or Propofol or

Ethomidate) Muscle relaxant (if mask ventilation easy) Endotracheal intubation Arteficial ventilation

Inhalational anesthesiaInhalational anesthesia

Inhalation anesthetics are gases (NInhalation anesthetics are gases (N22O) or vaporsO) or vapors::

Halothan, Enfluran, Isofluran, Sevofluran, DesfluranHalothan, Enfluran, Isofluran, Sevofluran, Desfluran

Inhaled anesthestics get into the alveoli of the Inhaled anesthestics get into the alveoli of the lung and according to the concentration gradient lung and according to the concentration gradient to the capillaries. The blood stream takes them to the capillaries. The blood stream takes them through the left heart to the brain.through the left heart to the brain.

Factors influencing the effectFactors influencing the effect

Concentration of the inhalation agent in the Concentration of the inhalation agent in the inhaled mixtureinhaled mixture

BreathingBreathing: minute ventillation, FRC: minute ventillation, FRC LungsLungs: diffusion, perfusion: diffusion, perfusion Solubility in blood, Solubility in blood, blood/gasblood/gas coefficient coefficient HeartHeart: cardiac output: cardiac output CerebralCerebral circulation circulation Oil/waterOil/water coefficient, boiling point coefficient, boiling point

Important valuesImportant values

Blood/gas coefficientBlood/gas coefficient::

Halothan:2.4 Isofluran 1.4 Sevofluran 0.6 Desfluran 0.4Halothan:2.4 Isofluran 1.4 Sevofluran 0.6 Desfluran 0.4

MACMAC= Minimal Alveolar Concentration= Minimal Alveolar Concentration

Concentration of an inhalation anesthestic which Concentration of an inhalation anesthestic which prevents movements at surgical incision in 50% of prevents movements at surgical incision in 50% of the patients.the patients.

1 MAC 1 MAC isofluranisofluran = = 1.15 volume%1.15 volume%

1 MAC 1 MAC sevofluransevofluran== 2 volume% 2 volume%

1 MAC 1 MAC desflurandesfluran = = 7.3 volume% 7.3 volume%

MAC reduced: by premedication, sedato-hypnotics, age, pregnancy, alcohol, hypthermia, hyponatremia, N2O co-administration

Inhalation anesthesia Inhalation anesthesia

Induction: Induction: High starting flow, relatively high concentrationHigh starting flow, relatively high concentration

filling up the system with the anestheticfilling up the system with the anesthetic„„Vital capacity rapid inhalation induction” (VCRII)Vital capacity rapid inhalation induction” (VCRII)

Maintenance: Maintenance: Gradually reduced concentration, reduced gas flow (at low Gradually reduced concentration, reduced gas flow (at low

flow the inhaled concentration is entirely different from the flow the inhaled concentration is entirely different from the concentration delivered by the vaporizer!)concentration delivered by the vaporizer!)

End of anesthesia: End of anesthesia: Closing the vaporizer depending on the type of agent, flow Closing the vaporizer depending on the type of agent, flow

and actual concentration.and actual concentration.

Indications for general anesthesia in Indications for general anesthesia in dentistrydentistry

Maxillofacial surgery Maxillofacial surgery Abscesses, other situations Abscesses, other situations

where local anesthesia is not effectivewhere local anesthesia is not effective Long, unpleasant dentoalveolar interventionsLong, unpleasant dentoalveolar interventions Dental treatment : patient comfortDental treatment : patient comfort

Goal of sedation for dental interventionsGoal of sedation for dental interventions

Easier tolerance of unpleasant interventions

Reduction of anxiety and connected risks and dangers

Prevention of pain and unpleasant experiences

Facilitate medical work

Very Very anxiousanxious patient patient Patients with Patients with elevated riskelevated risk of a exaggerated of a exaggerated

sympathoadrenal reaction sympathoadrenal reaction (hypertension, cardiac failure, (hypertension, cardiac failure, hyperthyreosis, paroxysmal tachycardia, etc.)hyperthyreosis, paroxysmal tachycardia, etc.)

All problem patients All problem patients (psychologic or medical risk)(psychologic or medical risk) Imbecile, demented patientsImbecile, demented patients Not cooperativeNot cooperative children children

Indication for sedation for dental Indication for sedation for dental interventionsinterventions

Grades of sedation - the transition from one to the other is contunuous!

Grade

Consciousness CNS Airways

Spontaneous breathing

Cardiovasc.sytem

Minimal monitorin

g

I. I. anxiolysianxiolysiss

Clear, reactions OK

Free OK OK inspection

II. II. „conscio„consciousus

sedationsedation””

Reacion t stimuli, lightly influenced

Free Usually satisfactor

y

Slightly affected

NIBP, HR, Sat O2 - - also post-sedation

III. Deep III. Deep

sedationsedation

Consciousness partly lost, falls asleep, reaction only to strong stimuli

Intervention often necessary

Usually ↓ assisted

ventillation necessary

Usually influence

d↓

As above + ECG

IV. IV. General General anesthesianesthesiaa

Loss of consciousnessno reaction to painful stimuli

Professionalairway

management

necessaryl!

Assisted or controlled ventilation necessary

Usually influence

d

Total anesthesio-logic equipment!!

Methods of sedationMethods of sedation

Verbal, psychologic methods - straightforward behaviour suggesting security, empathy, information and asking for consent!

Medical sedation Oral / rectal Intramuscular –rarely, for children (Ketamine 3-6 mg/kg) Intravenous Inhalation – only N2O/O2

- + vaporised inhalational anesthetics

Az oral (GI) sedation One hour before the intervention in adults

(½ hour in children) Prolonged action (sedation grade I. ) Drawbacks:

Not always practicable Diverse modes action in individual patients Inability ti drive afterwards (reaction-time ↑!) Synergistic action with other drugs (alcohol!)

Advantages: Simple, no need for numerous personal, usually no circulatory depression, can be administered by the doctor resposible for the intervention

Recommanded medication: Midazolam (7,5-15 mg) - for children0,3-0,4 mg/kg

(in Panadol syrup) Alprazolam (0,25-0,5 mg), (Diazepam)

Old patients are especially sensitive – administer with care!

Az inhalational sedation N2O/O2 for dental interventions Maximal concentration without the

danger of hypoxia (60%) causes superficial conscious sedation

(grade II.) Special equipment necessary Requires an extra doctor, expert in

airway management, mechanical ventilation and emergency techniques (anesthesiologist) , who is not involved in the dental intervention!

• Sedation with vaporized inhalation-anesthetics is already GA with the same objetive and

subjective conditions

Intravenous sedation

Opioids -Antidot: naloxone (0,l mg –repeated if necessary.)

For painful inteventions it is the first drug eg. fentanyl (1g/kg), alfentanil, sufentanil, remifentanil, pethidin

Danger: respiratory depression, synergism - administration is the task of an anesthesiologist!

Benzodiazepins - titrated administration, until we reach the intended grade of sedation

Midazolam: 0,03-0,05 mg/kg – 0,1-(0,15)mg/kgPrepare for airway management + mechanical ventilation! be careful in older patients – reduce doses!

Ketamine Propofol

TCI sedation: 2-2,5 g/ml as a target concentration

Használatuk aneszteziológus orvosi feladat!

Possible complication of Possible complication of sedationsedation

Apnoea, airway obstractionApnoea, airway obstraction Vomiting, aspirationVomiting, aspiration Circulatory depression, fall in BPCirculatory depression, fall in BP Allergic reaction, anaphylaxis, anaphylactoidAllergic reaction, anaphylaxis, anaphylactoid

Be allways prepared for all possible complications!

The intravenous and inhalational sedation requires the fulfillment of all subjective and objective conditions!!

Suitability for sedation/anesthesia in the dental practice

Anesthesiologic evaluation (preadmission Anesthesiologic evaluation (preadmission clinic!)clinic!) HistoryHistory Physical examinationPhysical examination Laboratory tests (?)Laboratory tests (?)

Preoperatice carency – NPO?Preoperatice carency – NPO? Bladder emptying, necessary preparationBladder emptying, necessary preparation

DocumentationDocumentation

Detailed petient information Signed „informed consent” Anesthesia sheet Post-sedation observation sheet Detailed operation instructions adapted to

the function of the ward (competencies, responsibilities,etc.)

Simplified discharge criteriaSimplified discharge criteria Stable vital functions for more than 1 hour The patient

Is well oriented in person, time, local conditions (mental state similar to the original)

can drink alone can urinate (regional anesthesia!) takes up cloths, walks without help

No PONV Serious pain (VAS <30) bleeding

Adult attendant Dentist and anesthesiologist agreed to discharge Home care arranged Written directions for the postoperative period

(name and telephone of the contact persons!)

CompetencyCompetencyGrade Doctor Nurse

I. anxiolysis doctor

responsible for the intervention

(dentist)

Dental nurse

II. „conscious sedation”+ independent

doctor with good knowledge in airway

management and emergency medical methods (specialist

anesthesist)!!!

?

III. Deep sedation Absolutly necessary the presence of a

specialist anesthesist!

The doctor, responsible for the intervention is not

allowed to make anesthesia or deep sedation even if he/she is specialized in

anesthesia as well!

Necessary/ recommended

IV. General anesthesia

Necessary

Objective conditionsObjective conditionsGrade

I. anxiolysis

II. „conscious sedation”

Easily accessible dental chair/operating table

O2 (cylinders, reductor, connectors, tubes, masks…) +airway management equipment, tools of mechanical

ventilation;Necessary equipment for intravenous access;

Strong suction-set, BLS accessorries, emergency medication and equipment

pulzoximeter, stetoscope, BP manometer

III. Deep sedation +

+ ECG, anesthesia machine, defibrillator, availability of quick medical help, ICU background, recovery room, supervising

stuff

IV. General anesthesia

Have a nice relaxed (but not sedated) afternoon!

General anaesthesiaGeneral anaesthesia

phases:phases: preparationpreparation induction maintenance emd of anesthesia (arousal) recoveryrecovery

pain relief!pain relief!

Old anesthesia methodsOld anesthesia methods Ether/chloroform… drip methodEther/chloroform… drip method Intravenous barbituratesIntravenous barbiturates

Gray method: intubation anesthesia (!) Gray method: intubation anesthesia (!) thiopenthal induction, thiopenthal induction,

maintenance: Nmaintenance: N22O/OO/O22, opioid, muscle relaxants, opioid, muscle relaxants

NLA type I. anesthesia:NLA type I. anesthesia:haloperidol + phenoperidin (N2O/O2)

NLA II.NLA II. anesthesia: anesthesia:dehydrobenzperidol (DHBP)+fentanyl

(N2O/O2)

DE CASTRO & MUNDELEER

Further modificationsFurther modifications TypeIITypeII. . neuroleptneurolept anesthesia anesthesia

Induction:Induction: DHBP 0,25-0,5 mg/kg Fentanyl 2-3g/kg + N2O/O2

Maintenance Fentanyl 1-1 g/kg, N2O/O2, muscle relaxants if necessary

ModifiedModified neuroleptneurolept anesthesia anesthesia Induction: Induction: DHBP 0,05-0,1 mg/kg

Fentanyl 1g/kg + N2O/O2

+ Thiopenthal –until the disapperance of the eyelid reflex

Maintenance: Maintenance: Fentanyl 1g/kg + N2O/O2, muscle relaxant

CoinductionCoinduction method method Induction: Induction: Midazolam 0,05 mg/kg, Fentanyl 1-2 Midazolam 0,05 mg/kg, Fentanyl 1-2 g/kgg/kg

Thiopenthal Thiopenthal - - until the disapperance of the eyelid reflex Maintenance:Maintenance: Fentanyl, Fentanyl, N2O/O2, muscle relaxant, , muscle relaxant,

with supplementation as necessary („balanced”)with supplementation as necessary („balanced”)

neurolept analgézia

Neurolept anesthesia/analgesiaNeurolept anesthesia/analgesia

Advantages:Advantages: Cooperable but emotionally indifferent patientCooperable but emotionally indifferent patient „ „ mineralisation”, mineralisation”, antinociceptionantinociception Possibility of balanced maintenancePossibility of balanced maintenance

Disadvantages:Disadvantages: DHBP is an DHBP is an receptor blocking agent – BP fall receptor blocking agent – BP fall

possible, prolonged actionpossible, prolonged action Control of anesthesia depth not easy, slow actionsControl of anesthesia depth not easy, slow actions

Induction by continuous infusionInduction by continuous infusion

Oxigygen inhalationOxigygen inhalation PropofolPropofol - TCI – - TCI –5-6 5-6 g/mlg/ml continuously reduced continuously reduced Remifentanil Remifentanil or or SufentanilSufentanil or or Fentanyl,Fentanyl,

(Fentanyl Fentanyl bolus 1-2 mg/kg1-2 mg/kg))RemifentanilRemifentanil: 5mg in 50 ml: 1 : 5mg in 50 ml: 1 g/kg bolus 0.05-1 g/kg bolus 0.05-1 g/kg/ming/kg/minFentanylFentanyl: 500 : 500 g (10 ml) diluted to 50 ml,g (10 ml) diluted to 50 ml,

1-2 mg/kg bolus, 100-150 mg(5-7.5 ml)/hour1-2 mg/kg bolus, 100-150 mg(5-7.5 ml)/hourCumulation!Cumulation!

After the patient is asleep, mask ventilation, than muscle After the patient is asleep, mask ventilation, than muscle relaxationrelaxation

IntubationIntubation

Monitoring of anesthesia depthMonitoring of anesthesia depth Changes in the ventilation type and frequencyChanges in the ventilation type and frequency Autonomic nerve responses to stimuliAutonomic nerve responses to stimuli Mechanical methodsMechanical methods

„„isolated upper arm”isolated upper arm” Measurement of lower oesophagus contractions Measurement of lower oesophagus contractions

(Measurement of the concentration of anesthetics in (Measurement of the concentration of anesthetics in the blood)the blood)

Cerebral electric activity measurementsCerebral electric activity measurements Cerebral function monitorCerebral function monitor BISBIS monitoringmonitoring PSI (physical state index)PSI (physical state index) AEPAEP

Important valuesImportant values

Blood/gas coefficientBlood/gas coefficient::

Halothan:2.4 Isofluran 1.4 Sevofluran 0.6 Desfluran 0.4Halothan:2.4 Isofluran 1.4 Sevofluran 0.6 Desfluran 0.4

MACMAC= Minimal Alveolar Concentration= Minimal Alveolar Concentration

Concentration of an inhalation anesthestic which Concentration of an inhalation anesthestic which prevents movements at surgical incision in 50% of prevents movements at surgical incision in 50% of the patients.the patients.

1 MAC 1 MAC isofluranisofluran = = 1.15 volume%1.15 volume%

1 MAC 1 MAC sevofluransevofluran== 2 volume% 2 volume%

1 MAC 1 MAC desflurandesfluran = = 7.3 volume% 7.3 volume%

MAC reduced: by premedication, sedato-hypnotics, age, pregnancy, alcohol, hypthermia, hyponatremia, N2O co-administration

Factors influencing the uptake of the Factors influencing the uptake of the inhalational agentinhalational agent

Inspiration concentration Inspiration concentration (parcial pressure)(parcial pressure) Alveolar ventillationAlveolar ventillation Blood/gas coefficientBlood/gas coefficient

bad solubility bad solubility – early saturation– early saturation Tissue uptake, saturationTissue uptake, saturation

A concentration difference between the end tidal A concentration difference between the end tidal (alveolar) and inhaled concentration: alveolar) and inhaled concentration: FFAA/F/FII – – equilibrium after long continuous administrationequilibrium after long continuous administration