This document discusses the history of anesthesia machines, airway equipment, and monitoring devices. It describes how early anesthesia machines evolved from simple mask delivery of ether or chloroform to Boyle's first continuous flow machine in 1912. Over time, machines incorporated vaporizers, improved flow meters, and safety features. Modern machines now include ventilators and patient monitoring. The document also outlines the development of airway devices like endotracheal tubes, laryngoscopes, and LMAs, as well as advances in monitoring such as blood pressure measurement and the concept of balanced anesthesia using multiple drugs.

1. DAY 3
 History of Anaesthesia machine,
airway and monitoring equipments
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2. Anesthesia machines
• In the late 19th century freestanding anesthesia machines were
manufactured in the United States and Europe.
• Three American dentist-entrepreneurs, Samuel S. White,
Charles Teter, and Jay Heidbrink, developed the first series of
U.S. instruments to use compressed cylinders of nitrous oxide
and oxygen.
Brian Sword's closed-circle anesthesia machine
(1930).
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3. Flow Meters
• In 1910, M. Neu had been the first to apply rotameters in anesthesia for
the administration of nitrous oxide and oxygen, but his machine was
not a commercial success, perhaps because of the great cost of nitrous
oxide in Germany at that time.
• Rotameters designed for use in German industry were first employed in
Britain in 1937 by Richard Salt; but as World War II approached, the
English were denied access to these sophisticated flow meters.
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4.  After World War II rotameters became regularly employed in
British anesthesia machines, although most American equipment
still featured non rotating floats.
 The now universal practice of displaying gas flow in liters per
minute was not a uniform part of all American machines until
more than a decade after World War II.
Flow Meters
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5. Vaporizers
• The Copper Kettle was the first temperature-compensated, accurate
vaporizer.
• It had been developed by Lucien Morris at the University of
Wisconsin in response to Ralph Waters' plan to test chloroform by
giving it in controlled concentrations.
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6. Anaesthesia machine
 A device used to support the administration of inhalational
anaesthetic agents and life sustaining gases
• Delivers a precisely-known but variable gas mixture,
including anesthetizing and life-sustaining gases to the fresh
gas flow outlet.
• Gases includes oxygen, air, nitrous oxide and vapours such
as halothane, isoflurane, sevoflurane or desflurane.
• Monitoring – machine and physiological parameters
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7. • Anasthesia equipments in the early days were primitive and a
simple device called a mask( Schimmelbusch) on which layers
of gauze were laid and volatile anaesthetic liquids like ether or
chloroform poured.
• This mask was kept on the patient’s face. As the patient
breathes in and out, the patient is rendered unconscious. This
system was called open system.
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8. • After meeting with lot of causalities with this equipment and
further innovation and improvement, a machine to deliver the
volatile liquid at a calculated guided manner was introduced.
This machine called Boyle’s anaesthesia apparatus, entered
the anaesthesia armamentarium.
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9. • The first anaesthesia machine (Boyle's machine) was invented
by Henry Edmund Gaskin Boyle in 1912 and it was the best
known early continuous flow anaesthetic machine.
• Prior to this time, anaesthetists often carried all their equipment
with them, but the development of heavy, bulky cylinder storage
and increasingly elaborate airway equipment meant that this was
no longer practical for most circumstances.
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Classification
1. Intermittent flow machine : Gas flows only during inspiration
• Drawover machine
• Egs: - Entonox apparatus ,Mackessons apparatus
2. Continuous flow machine : Gas flows both during inspiration
and expiration.
Egs : Boyle’s machine, Anaesthesia Workstation
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11. History
 Boyle anaesthetic machine , has undergone modification
– 1920-1926: Vaporizers bottles added
– 1930: plungers device in vaporizers bottle
– 1933: dry bobbin type of flowmeter instead of water sight-
feed type.
– 1937:Rotameters replaced dry bobbin type of flowmeter
– Various safety devices have been introduced and
modernized
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12. 12
Drawover Anaesthesia Machine
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Continuous flow machine
• Components
– Source of compressed gas
– Inline filters
– Pressure reducing valves
– Fail-safe valve
– Oxygen flush
– Flow meters
– Oxygen analyzer
– Vaporizer
– Ventilator
– Breathing circuit
– Scavenging system
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14. • The commonest type of anaesthetic machine in use in the
developed world is the Continuous – flow anaesthetic machine,
which is designed to provide
o An accurate &continuous supply of medical gases such as O2
and N2O mixed with an accurate concentration of anaesthetic
vapour ,and deliver to the patient at a safe pressure and flow.
 Modern machine incorporates
 ventilator , suction unit and patient monitoring devices .
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16.  Components of anesthesia machine
Comprises of three different pressure systems
o High pressure system: from cylinder to pressure reducing
valves.
o Intermediate pressure system: from pressure reducing
valves to flowmeters.
o Low pressure system: from flowmeters to the common
gas outlet on machine
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17. • There are several differences between newer and
older anesthesia machines.
• Advanced ventilators are the biggest difference
between newer and older gas machines.
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18. Airway equipments
 Methods for delivery of general anesthesia
• The techniques for delivery of general anesthesia and the drugs
used for that purpose were little changed from what was
available before the 20th century.
– by facemask
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19. • Beginning in 1930 and for the next several decades, there were
significant and rapid advances in general anesthetic methods,
and these improvements threatened to diminish the importance
of regional anesthesia.
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20. • The skills to perform this procedure were perfected
approximately 100 years ago by otorhinolaryngology specialists,
who like Chevalier Jackson, were often called to remove
foreign bodies from the airway.
• The Jackson laryngoscope was designed for such a purpose but
was quickly modified by anesthesiologists for inserting tracheal
tubes.
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21. • Arthur E. Guedel, Ralph M. Waters, and Ivan Macintosh
were quick to point out the advantages of the tracheal tube,
which included
• Protection of the patient’s airway
• Controlled positive-pressure ventilation of the lungs, and
• Convenient access to the surgical field for the head and
neck surgeon.
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22.  Endotracheal Tubes
• These are devices kept inside the trachea and used for delivering
anaesthetic gases and oxygen to the lungs.
• It helps in better control of ventilation and oxygenation .
• Early endotracheal tubes: the Magill tube and Oxford tube were
made of red rubber.
• The Magill tube came in an oral and nasal version with or without
an inflatable cuff.
• The Oxford tube was a short right-angled performed oral tube .
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23. • Red rubber is irritant at the point of contact.
• the standard transparent PVC tubes based on the original magill
red rubber tube.
• It can be introduced either through the nose or mouth.
• They have bevelled tracheal end to prevent injury to airway.
• Can be sterilized by boiling or autoclaving .
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24. 2) Endotracheal tube
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25. Endotracheal tube cuff
High volume
Low pressure cuff
Low volume
High pressure
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26. 3. LARYNGOSCOPE
 A laryngoscope is an instrument used to visualize the larynx
and to facilitate intubation of the trachea.
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27. Parts of Laryngoscopes
the parts of laryngoscopes are
as follows:
• Handle
• Electrical contact
• Flange
• Blade
• Bulb
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29. Types of Blades Used in
Laryngoscope
 Macintosh (curved)
• Adult : Macintosh blade,
 Miller (straight) blade
• small children : Miller
blade
 Wisconsin
 Macoy laryngoscope
 Polio laryngoscope
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30. LARYNGOSCOPIC BLADE
Miller blade Macintosh blade
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31.  Laryngeal Mask airway(LMA)
• LMA was introduced in 1983.
• an alternative airway device
• surrounds the glottic opening and is often used for
maintaining ventilation in selected elective surgical procedures
and as an alternative to tracheal intubation in cases of difficult
airway management.
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32. Laryngeal Masks (LMA)
• It is inserted blindly into the pharynx, forming a low-
pressure seal around the laryngeal inlet & permitting gentle
positive pressure ventilation. They cause less pain and
coughing than an endotracheal tube, and are much easier to
insert .
• It consists of an inflatable silicone mask and rubber
connecting tube.
• All parts are latex-free
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34.  Balanced Anesthesia
• In 1926, John S. Lundy, working at the Mayo Clinic,
introduced the concept of balanced anesthesia.
• emphasized the use of multiple drugs to produce
 Unconsciousness and antinociception
 Provide skeletal muscle relaxation, and
 Obliterate reflex responses.
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35. • No single anesthetic drug could provide all the characteristics of
an ideal general anesthesia, but a combination of IV analgesics,
Muscle relaxants & hypnotics given together produced the desired
balanced anesthetic.
• Lower doses of each drug could be used because the different
drugs tended to act synergistically.
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36. Now
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39. History of Monitoring devices
• The Riva Rocci method of blood pressure measurement was
described in 1896, and brief anesthetic records followed soon
after.
• These early records revealed alarming hemodynamic
responses to surgical stimuli in apparently adequately
anesthetized patients.
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40. • Monitoring of anesthesia for surgical procedures is a complex &
multifaceted skill that requires both knowledge and practice.
• The safety of your patient is dependent on your awareness and
response to potential problems.
• A thorough understanding of the principles of anesthetic
monitoring and awareness of normal and abnormal patient
parameters is crucial to providing safe anesthesia.
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41.  Parameters to be assessed continuously throughout anesthetic
period (recorded every 5 minutes):
1. Respiratory
• Airway, Respiratory rate, depth and character
• Oxygen saturation (SpO2)
2. Cardiovascular
• HR & rhythm, Pulse rate and strength
• Mucous membrane color and capillary refill time, ABP.
3. Body Temperature
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42. 4. Anesthetic depth/patient status
– Reflexes and muscle tone
– Eye position and pupillary reflex activity
– Heart and respiratory rates
– Status of surgical procedure
5. Equipment function
• Anesthetic level,
• Vaporizer and oxygen flowmeter settings
• Pressure relief (pop-off) valve
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43. Intra-operative roles
Other than induction, maintenance and extubation what else is
required intra-op?
Continuous monitoring (minimum)
trained anaesthetist
pulse oximetry
BP
ECG
capnography
If there is a problem with an
anaesthetised patient the situation
can deteriorate very rapidly. It is
essential to be constantly alert so
that response to critical incidents
is rapid.
Anaesthetist may be described as patient’s ‘advocate’ during the
surgery
The aim is to maintain CV stability and keep their physiology (including
fluid balance) as normal as possible
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Monitoring
• Machine function
– Oxygen analyzer
– Gas flow rates
– Pipeline pressure
– Cylinder pressure
– Gas analyzer
• Patient parameters
– Oxygenation
– Ventilation
– Circulation
– Body temperature
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Patient monitoring – essential!
• Oxygenation
– Oxygen analyzer: O2 concentration in breathing circuit
– Blood oxygenation: pulse oximetry
• Ventilation
– Capnography: end-tidal CO2
– Tidal volume
– Airway pressure
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Patient monitoring
• Circulation
– Blood pressure
– Pulse rate
– Electrocardiogram
• NB! Most important monitor =
Anaesthesiologist /Anaesthetist
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