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Anesthesia as a specialty

Past, present and future

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Reference book

• Clinical Anesthesiology,

G. Edward Morgan, Jr., Maged S. Mikhail, Michael J. Murray

Fourt Edition by the McGraw-Hill Companies 2006 a LANGE Medical Book

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www.katedraanest.cm-uj.krakow.pl

• Prof. Janusz Andres (Head of the Chair and Department)email: msandres@cyf-kr.edu.pl

• Agnieszka Frączek (Secretary)email: agafrk@cm-uj.krakow.pl

• Katarzyna Lepszy-Muszyńska (Coordinator, email:muszynscy.brzozowka@neostrada.pl

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Pain as a part of surgery

• Hypnosis

• Alkohol

• Botanical preparation

• Superficial surgery

• Galenic concept: body humors: blood, phlegm, yellow and black bile

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Inhalation Anesthesia

• 1540 Paracelsus: oil of vitriol (prepared by

Valerius Cordus and named “Aether” by

Frobenius): used to feed fowl: “it was taken

even by chickens and they fall asleep from

it for a while but awaken later without

harm”

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Local anesthesia

• Ancient Incas: coca leaf as a gift to the

Incas from the sun of God:

• destruction of Incas culture

• slaves payment

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Important names in history of anesthesia

• Humphry Davy: 1778 - 1829 (“laughing gas”, N20)

• Horace Wells: January 1845, Harvard Medical School, clinical use of N20

• William Morton: October 16,1846 ether for the excision of the vascular lesion from the neck (John Collin Warren: gentlemen this is not a humbug)

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Important names in the history of anesthesia

• Prof. Ludwik Bierkowski: February 1847 KRAKÓW ether in Poland

• anesthesia = temporary insensibility• James Simpson: November 1847, chloroform• John Snow : 1813-1858, first anesthesiologist,

face mask, vaporizer, clinical study • Joseph T. Clover follows John Snow

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American and British Origin

• Mayo Clinic and Cleveland Clinic• Students and nurses as anaesthetists• Long Island Society of Anesthetist 1905• New York Society of Anaesthetist 1911 became in

1936 ASA (Anaesthetists) in 1945 ASA (Anaesthesiologists)

• England: Sir Robert Macintosh in 1937 first Chair, Faculty of Anaesthetists of the Royal College of Surgeons was established in 1947

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Important names in the history of anesthesia

• Carl Koller 1857-1944, cocaine in ophthalmology

• Sir Magill (1888-1986)

• Arthur Guedel (1883-1956)

• Harold Griffith 1942 : curara

• Paul Janssen: intravenous anesthesia

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Important steps in development of anesthesia

• Ether (Morton)

• Regional (spinal, epidural) end of XIX century

• Thiopental 1934

• Curara 1942

• Halotane 1956

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Anesthesia

• analgesia

• reversible anesthetic effect

• amnesia

• areflexia

• sleep

• supression of the vegetative response

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Is anesthesia safe?

• Like airplane?

• Anesthesia related deaths:

• 1940 1/1000

• 1970 1/10 000

• 1995 1/250 000

• 2005 ?

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Safety of anesthesia

• 1950 - 25 000 deaths during 108 hours of anesthesia

• 2000 - 500 deaths during 108 hours of anesthesia

• Airplane risk (very low) - 5 deaths during 108 hours of flight

• Risk of anaesthesia: 100 x higher

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Receptor theory of anesthesia

• GABA: major inhibitory neurotransmitter (point of action of anesthetic drugs)

• Membrane structure and function: future of the anesthesiology

• Glutamate: major excitatory neurotransmitter

• Endorphins: analgesia • Unitary hypothesis of the inhalation agents

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Present status of anesthesiology

• Anesthesia

• Pain management

• Intensive Care Medicine

• Emergency Medicine

• Operative Medicine

• Education

• Research

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Practice of anaesthesiology is the practice of medicine (ABA)

• Assesment of, consultation for, and preparation of patients for anaesthesia

• Relief and prevention of pain• Monitor and maintenance of the perioperative

period• Management of critical ill patients• Clinical management and teaching of the CPR• Teaching, Research, Administration,

Transdisciplinary approach

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Progress in anesthesia

• New monitoring techniques and standards

• New anesthetics (iv and inhalation)

• New drugs (inotropic, NO)

• New ways of drug delivery

• New management techniques

• Cost - effective

• Fast truck

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Future of anesthesiology

• CNS and transdermal stimulation• Safe delivery of drugs• More specific drugs (membrane function)• Perfluorocarbons• Genetically focus therapy• Noninvasive monitoring• Visible pre- and postsynaptic area• Hibernation

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General anaesthesia and Preoperative evaluation

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ASA scale

• 1 normal healthy patient

• 2 mild systemic disease (no limitation0

• 3 moderate to severe systemic disease with limitation of function

• 4 severe systemic disease (threat to life)

• 5 moribund patient

• E emergency case

• 6 brain death patient

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An anaesthetic plan

• Patient’s baseline condition with medical record and previous anaesthesia and surgery

• Planned procedure

• Drug sensitivities

• Psychological makeup

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The anesthetic plan

• ASA physical status scale

• General versus regional

• Airway

• Induction

• Monitoring

• Intraoperative management

• Postoperative management

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ASA and perioperative mortality rate

• 1 0.07%

• 2 0.3%

• 3 2%

• 4 7-23%

• 5 9-51%

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Documentation

• Informed consent

• Preoperative note

• Intraoperative anesthesia record– patient status– review of anesthesia and surgery– laboratory– drugs dosage and time of administration

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Documentation 2

• Patient monitoring (intraoperative monitor, future reference for the patient, tool for quality assurance)

• fluid administration• procedures (catheters, caniulas, tubes)• time of important events• unusual complication• end of procedures• state of consciousness

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Safety of working place

• gas systems (liquid oxygen, air, a pin index system to avoid failure, Nitrous Oxide critical temperature 36,5 oC, different colours of the cylinders)

• electrical safety (leakage current on the OR less than 10 uA)

• surgical diathermy (malfunction of the return electrode may cause burns)

• fire and explosion (uncommon), temperature, humidity, ventilation, noise)

• www.apsf.org

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Ventilation management

• Breathing systems

• Open drop anesthesia

• Mapleson circuits

• Anesthesia machines

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Breathing Systems

• Patient – breathing system – anaesthesia machine

• Mapleson systems: Beathing tubes, fresh gas inlets, adjustable pressure limiting (APL) or pop-off valves, reservoir bags

• Carbon Dioxide Absorbent: CO2 + H2O = H2CO3,

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The anesthesia machine

• Receive medical gases from gas supply• Permits other gases (anaesthetics) only if there is

enough oxygen in the mixture• Vaporizers are agent- specific• Deliver and control tital volume• Waste gas scavenger system• Regulary inspections• Failure of the machine is a significant percentage

of the mishaps in anaesthesia practice

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Airway management

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Airway management

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Airway management

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Airway management

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Airway management

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Airway management

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Mask ventilation

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Mask ventilation

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Edotracheal intubation

Most common and safe protection of aiways during anaesthesia and

intensive careBut

Need skills and permament training

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AIRWAY

• Difficulty in managing the airway

• Difficult intubation

• Traumatic intubation

• Esophageal intubation

• Bronchial intubation

• Laryngospasm

• Bronchospasm

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Special airway techniques

• Fiberoptic intubation

• Retrograde (wire) intubation

• Transtracheal jet ventilation

• Lighted stylets

• Laryngeal mask

• Combitube

• Surgical airway

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Patient monitors

• Arterial blood pressure• ECG• CVP, PAC• Capnometry• Pulsoxymetry• EEG, BIS• Temperature• Nerve stimulation

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Inhalation anesthetic agents

• Nitrous oxide• Halothane (Fluothane)• Methoxyflurane (Penthrane)• Enflurane (Ethrane)• Isoflurane (Forane)• Desflurane (Suprane)• Sevoflurane (Ultane)• MAC concept

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Pharmacokinetics and pharmacodymanics

• Pharmacokinetics: how the body affects the drug

• Pharmacodymanics: how the drugs affects the body

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Factors affecting anesthetic uptake

• Solubility in blood

• Alveolar blood flow

• Differences in partial pressure between alveolar gas and venous blood

• Therefore: low output states predispose patients to overdosage of the soluble agents

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Factors affecting elimination

• Biotransformation: cytochrome P-450 (specifically CYP 2EI)

• Transcutaneous loss or exhalation

• Alveolus is the most important in elimination of the inhalation agents

• „Diffusion hypoxia” and the nitrous oxide

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Minimum alveolar concentration

• Is the concentration of inhaled anaesthetics in the alveolar that

prevents movements in 50% of patients in response to a standardized stimulus

(eg surgical incision)

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Inhalation anesthetic agents

• Nitrous oxide

• Halothane (Fluothane)

• Methoxyflurane (Penthrane)

• Enflurane (Ethrane)

• Isoflurane (Forane)

• Desflurane (Suprane)

• Sevoflurane (Ultane)

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Intravenous induction and anesthestic agents

• Thiopental• Metohexital• Benzodiazepins (Midazolam)• Propofol• Etomidate• Ketamine• Opioids• Droperidol

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Intravenous anaesthesia

• Changes in plasma concentration

• Absorption

• Distribution (Vd= Dose/Concentration)

• Biotransformation

• Excretion

• Compartment model of distribution and elimination

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Muscle relaxants

• Neuromuscular transmission

• Depolarizing agents (Ach rec. agonists)

• Nondepolarizing agents (Ach rec. antagonists)

• Cholinesterase inhibitors (edrofonium, neostigmine, pyridostigmine)

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Anticholinergic drugs

• Antimuscarinic effect

• Atropine

• Scopolamine

• Glycopyrrolate

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Anesthesia complications

• Inadequate preoperative planning and errors in patient preparation are the most commom causes of anesthestic complications

• Anesthesia and elective operations should not proceed until the patient is in optimal medical condition

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Anesthetic complications

• Human error (technical problems, lack of communication, experience, fatigue,)

• Ventilation (breathing circuit, defect of monitoring equipment, anesthesia machine)

• Position (periferal nerve damage)

• Anaphylaxis

• Latex allergy

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Anesthesia and perioperative complications

• Airway

• Circulation

• Central and peripheral nervous system

• Pain therapy

• Drugs used in anesthesia

• Equipment failure