Basisbegrippen Anesthesie

University Hospitals Ghent

Basisbegrippen Anesthesie InterUniversitair Postgraduaat Onderwijs in de Heelkunde Gent, April 2010 Patrick F Wouters

Acute Medical Care University Hospitals Ghent

Current Diagnosis & Treatment Ch 11 : Anesthesia Theodore J. Sanford Jr., MD

History / definition of anesthesia

Risk of anesthesia Preoperative Evaluation The Operating Room Common Postoperative Problems

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"Gentlemen, this is no humbug."

"I did not experience pain at any time, though I knew that the operation was proceeding."

W Morton - the first successful demonstration of ether anesthesia Massachusetts General Hospital on October 16, 1846


Historiek van algemene anesthesie Nitrous Oxide (lachgas)

J Priestley - 1772

H. Davy (1778-1829) ‘recreational use’ 1844 H. Wells-Boston : tandextractie

Ether (diethylether)

V Cordus - 1540

In 1842 Clarke – tandextractie; Crawford Long -chirurgie. in 1846 Eerste gepubliceerde demo : William Morton - Boston

Chloroform von Leibig, Guthrie, Soubeiran - 1831 Door James Simpson geintroduceerd - bevallingen In1847 H Coote - chirurgie

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Inhalational anesthetics drugs - Anesthesie dampen

Ether = ontvlambaar

Isoflurane Enflurane

Sevoflurane

Halothane

Desflurane

- Anesthesie gassen :

Lachgas (N2O) Xenon (edelgas)


“Triad” Of Anaesthesia Barbituraten Propofol Etomidate

HYPNOSIS

AMNESIA

(sleep: sedation / anxiolysis)

Benzodiazepines

GENERAL ANAESTHESIA Curares Opiaten

RELAXATION (muscle relaxation)

ANALGESIA (pain relief) 7

locale - regionale - algemene Anesthesie ALGEMEEN

LOKAAL

LOCOREGIONAAL


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Centrale Effecten Algemene Anesthesie Bewustzijnsverlies Verlies controle slikfunctie Verminderde tonus in tong- en verhemelte – en

pharynxspieren Onderdrukking spontane ademhaling Daling orthosympathische tonus – bloeddrukval

Vitale Functies Bedreigd !

Anesthesie toedienen =

Ondersteuning / Vervanging / Bewaking van vitale functies - ononderbroken 11


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Anesthesia – related Mortality 1941 : Pearl Harbor 1: 450 anesthesia-related deaths

1950 - 60 : Beecher and Todd (USA) Anesthesia primary cause of death in 1 : 2.000

1970 - 80 : Lunn and Mushin (UK) anesthesia-related death rate 1 : 5.000

1985 : Safety becomes TOP PRIORITY in Anesthesia

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Safety standards and monitoring 1985 • • • • •

Pulse oximeters Capnometrie ECG Bloeddruk Temperatuur


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Is Anesthesia really Safe now ? Odds to die on a single airline flight in top 25 airlines : 1 / 10 460 000 (in bottom 25 airlines :1/723 819)

versus

Odds to die from anesthetic : 1 / 250 000

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Human factors Even when fatigued, I perform effectively during a critical phase 100%

disagree neutral

50%

agree

0% Anesthetist

Pilot

Surgeon

Junior members should not question the decisions made by senior team members 100%

disagree neutral agree

50% 0% Anesthetist

Pilot

Surgeon

BMJ 2000;320:745–9 17


Human Factors : Teamwork

BMJ 2000;320:745–9

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1 per 250 000 refers to : ASA 1 and 2 patients only Deaths primarily or solely due to anesthesia

New data in representative sample : about 1/500 perioperative deaths Anesthesia contributes to 3-5 % of overall mortality = 1/13 000 Claims for „progress‟ and „role model for safety‟ are not justified…

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Complicaties in de perioperatieve faze Respiratoir (bij kinderen x 3-5) Luchtwegcontrole Ademhaling

Anafylaxis Vergissingen met Medicatie – Transfusie Zenuwletsels Locoregionale anesthesie Positionering

Cardiovasculair Shock – orgaanfalen Ischem optische neuropathy Myocardinfarct Hartfalen 20


Anesthesia management in CABG

Proficiency ! 21


„Anesthesia management‟ ? Dealing with the (side) effects of anesthesia Safety issues

Dealing with the effects of a surgical intervention Preserve homeostasis blood loss ischemia-reperfusion

pain- stress Inflammation Coagulation - thrombosis

Comprehend the pathophysiological effects of surgery Use strategies to minimize the consequences

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Perioperative Risk

Anesthesia Type of Surgery Patient s Condition

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Preoperatieve Evaluatie : doel Risicobepaling Risk/benefit Informed consent

Risicoreductie-Optimalisatie van perioperatief

plan : tijd ! Medicatie pre-post Type anesthesie Adaptatie chirurgisch plan Postoperatieve zorgtraject

Informatief gesprek - geruststelling 24

Preoperatief nuchter-beleid • Gevaar = aspiratie maaginhoud Leeftijd

Vast voedsel, melk (poeder & borstvoeding)

Heldere vloeistof

< 6 maand

4 uur

2 uur

6 – 36 maand

6 uur

2 – 3 uur

> 36 maand

6 – 8 uur

2 – 3 uur

Praktisch : volwassenen = npo na 24 hr


The Mallampati Classification

Cormack and Lehane (direct laryngoscopy) 26


Anamnese / vragenlijst Allergie (Latex !) Persoonlijke en Familiale problemen met anesthesie Luchtweg Maligne hyperthermie Pseudocholinesterase deficiëntie Awareness

Medicatie – Druggebruik (alcohol) Comorbiditeit

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Comorbiditeit Cardiovasculair Pulmonaal Nierfalen Leverfalen Endocriene – metabole afwijkingen DM, Obesitas, Schildklier

Neurologisch Hemorragische Diathesen Infecties Medicatie

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ASA classificatie = inschatting van risico van anesthesie + chirurgie ASA 1: normale gezonde persoon, geen medicatie ASA 2: lichte systeemaandoening, geen belemmering van dagdagelijkse activiteit ASA 3: ernstige systeemziekte, onder medicatie en

belemmering van de dagelijkse activiteit ASA 4: zeer ernstige systeemaandoening, chronische bedreiging van het leven

ASA 5: stervende patiënt E: dringende ingreep 29

ASA classification and peroperative mortality rates

Class

Mortality Rate

I II III IV V

0.06 - 0.08 % 0.27 - 0.4 % 1.8 - 4.3 % 7.8 - 23 % 9.4 - 54 %


Technische Onderzoeken

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Preoperatieve medicatie Niet onderbreken : Beta blockers Statines Aspirine

Stoppen : ACE-inhibitoren + Angiotensine II blockers (sartanen) ? Sulfonylurea Thienopyridines (3d) – cave type ingreep / DEStents

Premedicatie : Benzodiazepines : amnesie + anxiolyse 32


Cardiovasculaire status MACE = belangrijkste perioperatieve doodsoorzaak IHD aanwezig in 25 – 30 % van chirurgische populatie vs < 20 % in algemene populatie

Vasculaire 40-60 %

Cardiovasculaire complicaties in 3-4 % van chirurgische interventies J Cardiothorac Vasc Anesth. 2004 ;18:1-6

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Shear Stress Inflammation

Natural Healing Process

Consolidation

Plaque rupture


Pathology of perioperative MI

- Plaque rupture, hemorraghe, thrombosis in > 50 % of all cases - Same as in non-surgical pts - Fatal PMI associated with LM disease (20%) 3V disease (60%)

Int J Cardiology 1996;57:37-44 Cardiovasc Path 1999;8:133-935


Vulnerable Blood

Surgery

Circulation. 2003;108:1772-1778 36


Risk Reduction strategies : beta-blockers Poldermans et al NEJM 1999;341:1789-94

CER 34 % - ARR 30 % - Relative Risk Reduction 88 % 37

The POISE trial - Lancet 2008 ; 371:1839-47

Myocardial Infarction

Composite

Stroke

Mortality

Limitations : Long acting metoprolol High dose Late startup

Circulation 2002;106:1024-1028

Risk rhabdomyolysis & myopathy – Cerivastatin withdrawal


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de Souza DG, Baum VC, Ballert NM: Late thrombosis (> 1 year) of a drug-eluting stent presenting in the perioperative period. ANESTHESIOLOGY 2007; 106:1057–9

ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Executive Summary Circulation. 2007;116:1971-1996


Computer voor Anesthesisten

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Inductie anesthesie Luchtwegcontrole Preoxygenatie Full monitoring All alert

Can not Intubate : Control airway with mask Strategy (fiberoptic)

Can not Intubate + Can not Ventilate !!! 3 min hypoxia = brain damage Invasive Airway

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The continuum of anesthetic depth

Depth of hypnosis

Awake

Conscious sedation

Too light

Unconscious sedation (+ LRA)

Adequate

Too deep

Time

Bispectral Index EEG (BIS)



 



Separation of the EEG into the sole frequency components using the fast fourier transformation (FFT) The result of FFT is the power spectrum Determination of power spectrum about a EEG epoch, redetermination and addition of the results of the new power spectrum at all 7.5-30 sec continuously BIS is a dimensionsless count between 0-100

BIS

Depth of anaesthesia

100-90

awake, recall

85-65

Sedation

40-60(65?)

General Anaesthesia

40-35

Deep Anaesthesia, no explicit or implict memory (recall)

<40

Start burst-suppression pattern

<30

Increased burstsuppression pattern

0

Zero line EEG

Awareness : 0.1-0.2 % - auditory perception - sensation of paralysis - anxiety - helplessness - panic >> 70 % : sleep disturbances, dreams, nightmares, flashbacks,… ?%

: P.T.S.S. ( repititive nightmares, anxiety, irritability, preoccupation with death,…)

(ref.: Schwender et al. BJA, 1998, 80, 133-139) (ref.: Domino et al. Anesthesiology 1999, 90, 1053 - 61)


Malignant Hyperthermia (MH) Genetically inherited muscle disease Ryanodine receptor – massive SR calcium release Abnormal response to suxamethonium (masseter spasm) and volatile anesthetics

Muscle contracture – hypermetabolism Tachycardia (possibly arrhythmias), Hyperkalemia, Hyperthermia, Hypercarbia, Metabolic Acidosis, Cyanosis, Muscle stiffness, rhabdomyolysis

Fatal if untreated : Dantrolene 2mg/kg to 10 mg/kg

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Anaesthesia in suspected malignant hyperthermia Avoid Succinylcholine and volatile Anesthetics Purge Anesthesia Circuit 12 hrs

Regional anaesthesia all drugs safe

General anaesthesia premedication: benzodiazepine, opiates induction: all intravenous drugs safe neuromuscular blockade: all non-depolarising drugs safe maintenance: N2O - O2 – total intravenous

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Uitleiding Anesthesie : “Wakker Maken” Niet door ANTIDOTUM Wel voor stopzetten NMB werking : cholinesterase remmers / suggamadex Uitz : opiaat receptor antagonist naloxone

Stop toediening hypnoticum - Correct inschatten bloedspiegels : spontane eliminatie van slaapmiddel Bij voorkeur kortwerkende – ook bij cumulatieve dosis – hypnotica, analgetica, NMB met voorspelbare pharmacokinetisch gedrag

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Ontwaken – risico‟s Luchtwegobstructie Rillen Nausea en braken Agitatie, delirium Pijn Hypothermie Labiliteit autonoom zenuwstelsel

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Postoperative hypoxaemia Hypoventilation airway obstruction central respiratory depression respiratory muscle weakness

Ventilation/perfusion abnormalities - Attelectasis Increased oxygen consumption Shivering, pain

Impaired response to hypoxaemia Decreased oxygen delivery low cardiac output low haemoglobin values

Pneumothorax (central venous lines) Pulmonary Embolus (thromboprofylaxis)

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Hypothermie Zuurstofverbruik – risico MI Stollingsstoornisen Vertraagd ontwaken Infectie Voorkomen : Toedekken voor inductie Zaaltemperatuur Rebreathing anesthesie circuit Opwarmen IV vloeistoffen

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PONV : “The Big Little Problem” Incidentie 20-30 % (70 % in hoog risico) Patient predisposition age, sex, menstrual cycle, obesity history PONV - motion sickness Surgical factors type of surgery : gynecology Anaesthetic factors Etomidate (vomidate) >>>> Propofol Opioids

Postoperative factors Pain, hypotension, early mobilisation first intake of fluids/food ??? 60


PONV : “The Big Little Problem” Profylaxis 5-HT3 receptor antagonists Dexamethasone Droperidol

Treatment 5-HT3 receptor antagonists

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Claimed advantages of good postoperative analgesia Humanitarian reasons Psychological reasons Less respiratory complications Less adverse cardiovascular responses Less automatic complications (sweating, vomiting) Earlier mobilisation Less deep vein thrombosis Earlier return to normal life style / work

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General plan for postoperative analgesia Systemic drugs Nonsteroidal anti-inflammatory drugs, paracetamol Opiates Route Intravenous (intramuscular-subcutaneous-rectal) Oral

Mode of administration Patient-controlled or by medical staff Continuous versus intermittent methods

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General plan for postoperative analgesia Regional Anaesthetic techniques Local anaesthetic agent +/- opioid Route Epidural – Spinal – Caudal Paravertebral Regional nerve blocks Wound infiltration

Mode of administration single bolus at surgery Intermittent on demand Infusion

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Locoregional Anesthesia Neuraxial Anesthesia :Spinal – Epidural – CSE

Segmental Nerve conduction block 65


Thoracic epidural

Lumbar epidural

Spinal


Compensatory vasoconstriction

Anesthesiology 1995 ; 83 : 604-610

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hemodynamic effects of neuraxial sympatholysis Local anesthetics produce non-selective nerve conduction block Autonomic NS > Sensory fibers >> Motor fibers

Vascular effects : pregangl thoracolumbar sympathetic Reduced tone Arterial & Venous Degree of vasodilation ~ extend of block Compensatory vasoconstriction in unblocked segments

Cardiac effects (Th 1-4) Negative Inotropic – Dromotropic – Chronotropic 68


Complicaties – neuraxiale anesthesie Postdurale hoofdpijn – duralek : Epidurale bloedpatch

Epiduraal hematoom : Snelle diagnose en therapie

Zenuwschade mechanisch of door neurotoxiciteit locale anesthetica (?) Meestal door foutieve positionering op operatietafel

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Statins


Postoperative treatment CABG : Aspirin

N Engl J Med, Vol. 347, No. 17

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Anesthesie Plan Algemene Volatiele Intraveneuze Luchtweg (OTT-NTT-LM)

Of/en Locoregionale Neuraxiaal of perifeer block Regio – uitgebreidheid Duur van ingreep (+sedatie) Contra indicaties Stolling Infectie

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Causes of death Cancer 51.7 % Cardiovascular 17.2 % Anesth Analg 2005;100:4–10 76


Werkingsmechanisme : de Meyer-Overton regel

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Basisbegrippen Anesthesie

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