mapleson circuits used in anesthesia practice, are in their way out but it is as important to know the mechanism with which the gases flow to and fro through them.
mapleson circuits used in anesthesia practice, are in their way out but it is as important to know the mechanism with which the gases flow to and fro through them.
Neuromuscular monitoring, also known as train of four monitoring, is a technique used during recovery from the application of general anesthesia to objectively determine how well a patient's muscles are able to function. It involves the application of electrical stimulation to nerves and recording of muscle response using, for example, an acceleromyograph. Neuromuscular monitoring is typically used when neuromuscular-blocking drugs have been part of the general anesthesia and the doctor wishes to avoid postoperative residual curarization (PORC) in the patient, that is, the residual paralysis of muscles stemming from these drugs.
Neuromuscular monitoring, also known as train of four monitoring, is a technique used during recovery from the application of general anesthesia to objectively determine how well a patient's muscles are able to function. It involves the application of electrical stimulation to nerves and recording of muscle response using, for example, an acceleromyograph. Neuromuscular monitoring is typically used when neuromuscular-blocking drugs have been part of the general anesthesia and the doctor wishes to avoid postoperative residual curarization (PORC) in the patient, that is, the residual paralysis of muscles stemming from these drugs.
Prof. Mridul Panditrao wants to share his much acclaimed CME lecture in ISACON 2014, Madurai, India and many other places, on one of the very very important but often ununderstood and neglected essential topics in Anesthesia..... Vaporizers!!
Health & Beauty Packages-Ananta Spa & ResortRahul Roy
Ananta Spa & Resorts is one of the prominent hotels in Udaipur known for its hospitality and luxurious feelings. The hotel has the cheap rate among other Udaipur Hotels.
Objectives, applications and factors on evaporationAkankshaPatel55
Evaporation is a specific type of heat exchange where a liquid changes its state into a gas. It's a crucial process in nature and has many significant applications.
Factors affecting evaporation rate:
Temperature: The warmer the liquid and surrounding air, the faster the molecules move and gain enough energy to escape, increasing evaporation rate.
Humidity: The amount of water vapor already present in the air (humidity) affects how readily new vapor can be absorbed. Higher humidity slows down evaporation.
Wind speed: Moving air removes evaporated molecules from the surface, preventing them from building up and slowing down further evaporation. Higher wind speeds increase evaporation rate.
Surface area: The larger the exposed surface area of the liquid, the more molecules have the chance to escape, leading to faster evaporation.
Liquid properties: Different liquids have different internal molecular forces and boiling points, impacting how easily they evaporate. For example, alcohol evaporates faster than water due to weaker molecular forces.
Consequences of evaporation:
Cooling: During evaporation, energy is used to break the bonds between water molecules, resulting in a cooling effect on the remaining liquid. This is why sweating feels cool on your skin.
Water cycle: Evaporation is the first step in the water cycle, where water continuously moves between Earth's surface and atmosphere. Water vapor rises, condenses into clouds, and eventually falls back to Earth as precipitation.
Salinity: As water evaporates from oceans and lakes, dissolved salts become more concentrated, impacting marine ecosystems.
Human activities: We use evaporation in various applications, like cooling towers in power plants, humidifiers, and drying processes.
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
This PPT contained slides for Steam distribution system, which is a third unit in Energy Conservation subject of final year in Mechanical Engineering Branch.
The content of PPT are mentioned below:
Steam Distribution System, Thermodynamics, Heat, Properties of steam, steam, steam system, PDRS, Steam pipe installation, Dryers, Operation and maintenance of steam traps, Condensate Recovery System, Flash Recovery System, Energy Conservation Opportunity in Steam Distribution System.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
Contact us if you are interested:
Email / Skype : kefaya1771@gmail.com
Threema: PXHY5PDH
New BATCH Ku !!! MUCH IN DEMAND FAST SALE EVERY BATCH HAPPY GOOD EFFECT BIG BATCH !
Contact me on Threema or skype to start big business!!
Hot-sale products:
NEW HOT EUTYLONE WHITE CRYSTAL!!
5cl-adba precursor (semi finished )
5cl-adba raw materials
ADBB precursor (semi finished )
ADBB raw materials
APVP powder
5fadb/4f-adb
Jwh018 / Jwh210
Eutylone crystal
Protonitazene (hydrochloride) CAS: 119276-01-6
Flubrotizolam CAS: 57801-95-3
Metonitazene CAS: 14680-51-4
Payment terms: Western Union,MoneyGram,Bitcoin or USDT.
Deliver Time: Usually 7-15days
Shipping method: FedEx, TNT, DHL,UPS etc.Our deliveries are 100% safe, fast, reliable and discreet.
Samples will be sent for your evaluation!If you are interested in, please contact me, let's talk details.
We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
2. Introduction
▪ A vaporizer (anesthetic agent or vapor
delivery device) changes a liquid
anesthetic agent into its vapor and adds
a controlled amount of that vapor to the
fresh gas flow to the breathing system.
Up to three vaporizers are commonly
attached to an anesthesia machine, but
only one can be used at a time.
3. Historical aspects
▪ ‘Inhalational Anesthesia’ tried by early ‘clinicians’ from time immemorial
▪ Historical records show use of “Soporific sponges” soaked in
‘medicinal elixirs’
▪ Actual use of easily ‘vaporizable substances’ came much later, in 18th
century, 16th October 1846 to be exact
▪ WTG Morton used his ‘ Letheon’ inhaler - Ether inhaler first time to
achieve surgical anesthesia, as a public demonstration, in the history
of mankind.
▪ Thus ether then chloroform again back to ether, Led to evolution
of various devices used for vaporization of these liquids
4. Historical aspects
▪ The main ‘reviver’ of ether was Kurt Schimmelbusch and his ‘mask’
▪ Contraption made with wires and layer of gauze pieces/used along with
‘open ether - drop by drop method’ for administration of ether.
▪ “Yankauer’s mask” in 1904, Flagg’s can/ KEM Bottle,
▪ More sophistication: Epstein Macintosh Oxford (EMO) vaporizer with Oxford
inflating bellows (OIB)
▪ “Anesthesia Machine” was invented.
5. Historical aspects:
▪ With deeper insights into physical principles, properties and laws
▪ Advances for development of more sophisticated devices
▪ As a result Oxford Miniature Vaporizer (OMV), Copper Kettle.
▪ halogenated compounds like halothane/halogenated ethers
▪ has produced the Tec series of vaporizers.
▪ Presently available modern vaporizers
▪ advanced in their construction capable of delivering precise, predictable
and calculated/ constant concentration of the Volatile anesthetic agent.
▪ Thus the humble beginning has evolved in to a precision perfect and
an analytical science.
6. Physical principles:
▪ Heat of Vaporization
▪ The Number of calories required to vaporize 1 ml. of the liquid
▪ Latent heat of vaporization
▪ The Number of calories needed to convert 1 gram of liquid to vapor without a
temperature change
▪ Temperature of remaining liquid falls and may decrease rate of vaporization
▪ Specific heat
▪ The quantity of heat energy required to increase the temperature of a 1 gm. of
a substance/1 ml. of a liquid by 10 Celsius is called the Specific Heat of the
substance/ liquid.
▪ Thermal conductivity
▪ Measure of speed with which heat flows through a substance.
7.
8. There are a number of ways of classifying vaporizers:
Mechanism for adding anaesthetic vapour to the fresh gas flow
▪ Variable bypass
▪ Measured flow
The internal resistance of the vaporizer
▪ High: plenum vaporizers
▪ Low: draw-over
Temperature compensation
▪ High thermal conductivity and specific heat capacity of the jacket (a ‘heat sink’)
▪ Automatic adjustment of the splitting ratio:
1. Bimetallic strip
2. Bellows
3. Electronically controlled
9. Mechanism for adding anaesthetic vapour to the fresh gas flow
Volatile anaesthetics are too potent to be used at their saturated vapour
pressure and must therefore be diluted to a safe concentration before being
delivered to the patient. This is commonly achieved in one of two ways’
▪ Variable bypass vaporizers (e.g. most modern vaporizers, apart from the Tec
6) split the fresh gas flow into two streams. One stream enters a vaporization
chamber and leaves fully saturated with anaesthetic vapour, whilst the
remainder of the fresh gas bypasses this chamber. The two gas flows are
reunited downstream to produce the desired final concentration. Altering the
FGF does not alter the ratio between the flows in the two streams (splitting
ratio) and therefore does not alter the final concentration.
▪ Measured flow vaporizers (e.g. the Tec 6 desflurane vaporizer) use a separate
heated and pressurized vapour stream that is precisely injected into the FGF.
Increasing the FGF dilutes the output and therefore an automated mechanism
compensates for this.
11. The internal resistance of the vaporizer
▪ Draw-over vaporizers have low internal resistances to gas flow. The patient’s
inspiratory effort is sufficient to draw fresh gas through the vaporizer and draw-
over vaporizers are therefore useful in the field where pressurized gas may not be
available. Mechanisms to improve the accuracy of anaesthetic delivery, such a
baffles and temperature compensation increase resistance and are not usually
present in draw-over vaporizers, leading to unpredictable performance. Examples,
the Goldman, the Oxford Miniature Vaporizer (OMV) and Epstein and Macintosh of
Oxford (EMO) vaporizers. These vaporizers are used within the breathing system.
▪ Plenum vaporizers in contrast rely on pressurized gas flow rather than the
patient’s inspiratory effort. They have a high internal resistance and are used with
continuous flow anaesthetic machines. A plenum vaporizer should saturate all gas
that passes through the vaporization chamber in order to achieve a consistent
output, even at high FGFs. Examples: Boyle’s bottle, the Copper kettle, the Tec 5
series and the Aladin cassette. These vaporizers are used outside the breathing
system.
12. Temperature compensation
▪ Latent heat of vaporization, when Left unchecked, the temperature of the
remaining liquid anaesthetic will fall significantly, along with its saturated
vapour pressure and therefore lead to a reduction in the output of the
vaporizer.
▪ The first method used to compensate for the latent heat of vaporization is to
use a heat sink, such as a water bath (Boyle’s bottle) or a large mass of
copper. Modern vaporizers are still made of large masses of metal for this
purpose.
▪ Invariably though, there will be some drop in temperature within the vaporizer
as it is used. To maintain a constant output, this drop in temperature and
saturated vapour pressure of the anaesthetic must be compensated for. This
is achieved by the use of devices such as bimetallic strips, bellows or
electronic control.
13. The concentration of anaesthetic produced by the
vaporizer depends on the fraction of fresh gas that is
diverted into the vaporizing chamber. This fraction is
governed by the calibrated control dial. The proportion
bypassing divided by the proportion entering the
vaporizing chamber is known as the splitting ratio.
In order to ensure that the end concentration is controlled
only by the splitting ratio and not by variations in the
amount of anaesthetic leaving the vaporizing chamber, the
diverted gas must always become fully saturated with
vapour before it re-joins the bypass gas. This is achieved
using wicks that increase the surface area for evaporation
of the anaesthetic liquid and baffles that direct the
incoming gas down closer to the surface of the liquid.
These features significantly increase the internal
resistance of the vaporizer.
14. Bimetallic strips
The bimetallic strip consists of strips two different metals joined together.
The metals have different coefficients of thermal expansion, and they are
wound into a coil. As the temperature increases, one metal will expand
more than the other, causing the coil to loosen. Similarly, the coil will
tighten as the temperature decreases. At the centre of the coil is a
pointer, which moves across a calibrated dial as the coil tightens or
loosens so that the temperature can be read.
▪ Advantages
Cheap.
▪ Disadvantages
Limited accuracy and slow response times.
15. Characteristics of Ideal VAPORIZER
▪ Performance not affected by changes in
▪ FGF,
▪ Volume of liquid agent,
▪ Ambient temperature & pressure,
▪ Decrease in temperature & pressure
▪ Low resistance to flow
▪ Light weight with small liquid requirement
▪ Economical and safe to use
▪ Corrosion and solvent-resistant
16. Features of modern vaporizer
▪ Variable bypass
▪ Fresh gas splits into bypass gas and carrier gas
▪ Flow over
▪ Carrier gas flows over the surface of the liquid volatile agent in the vaporizing chamber
▪ Temperature compensated
▪ Equipped with automatic devices that ensure steady vaporizer output over a wide range
of ambient temperatures
▪ Agent-specific
▪ Only calibrated for a single gas, usually with keyed fillers
▪ Out of circuit
17. Property TEC 4, Vapor
19n, 2000,
Aladin
TEC 5 TEC 7 Vapor 19n Vapor 2000 D Vapor
TEC 6 Des.
Principle of
vaporization
Flow over, Flow over Flow over Flow over Flow over Gas-vapor blender
Carrier gas flow Variable bypass Variable bypass Variable bypass Variable bypass Variable bypass Dual circuit
Capacity mls.
With dry wicks
With wet wicks
135
100
300
225 225
200
140
360
280
D-vapor 300
TEC 6: 425
Thermo-
compensation
Automatic Automatic Automatic Automatic Automatic Thermostatically controlled at
39 0C.
Position Out of circuit Out of circuit Out of circuit Out of circuit Out of circuit Out of circuit
specificity Agent-specific Agent-specific Agent-specific Agent-specific Agent-specific Agent-specific
Low flow suitability Not very good Good Very Good Good Very Good Very Good
Comparative properties
18. OLD VAPORIZERS
MORTON’S ETHER INHALER
Draw over, flow over with wicks, concentration not calibrated,
temperature not compensated, agent specific.
19. OPEN DROP METHOD
Draw over, flow over without wicks, concentration not calibrated,
temperature not compensated, multiple agent.
20. BOYLES BOTTLE (1920)
Plenum type, variable bypass, flow over or bubble through, concentration
poorly calibrated, temperature not compensated, agent specific, out of circle.
Advantages
• Could be used with several different anaesthetic agents.
• Full saturation of the vapour chamber gas flow was
possible.
Disadvantages
• No temperature compensation so volatile output fell as
the reservoir cooled.
• The concentration of anaesthetic delivered to the patient
was imprecise.
• Tipping Boyle’s bottle could lead to dangerous rises in
anaesthetic concentrations
Used with early continuous flow anaesthetic machines to deliver ether, trichloroethylene or chloroform.
21. GOLDMANS VAPORIZER (1959)
Plenum or Draw over type ,variable bypass, flow over, temperature not
compensated, concentration poorly calibrated, multiple agent, both inside
and outside circle.
Advantages
• Small and cheap.
• Simple to use and service.
• Lightweight and portable.
• Restricted output prevents halothane overdosing.
Disadvantages
• Variable output that is difficult to measure.
• No temperature compensation.
• Unsuitable for use with less potent anaesthetic agents, because it is
inherently inefficient.
• There is a risk of anaesthetic agent spillage into the breathing system.
22. Oxford miniature vaporizer (OMV)
Variable bypass, draw-over vaporizer, not actively temperature compensated, but it
does incorporate an ethylene glycol heat sink, low resistance
Advantages
• Portable.
• Robust and easily serviceable.
• Most volatile agents can be used by simply switching the interchangeable
dials.
• When the control dial is switched off, volatile agent cannot easily spill into the
breathing circuit if the vaporizer is tilted or inverted.
• An ethylene glycol heat sink buffers temperature changes, to an extent.
• Metal mesh wicks help increase the output of the vaporizer.
• Acceptable accuracy over a range of flow rates and tidal volumes.
Disadvantages
• Not temperature compensated.
• Small 50 ml reservoir empties quickly.
The OMV remains in current use as part of the British military’s Triservice apparatus for delivering anaesthesia in
the field, typically with isoflurane, but also sevoflurane.
23. EPSTIEN MACINTOSH OXFORD (E.M.O.) (1952)
Draw Over, Concentration calibrated, Flow over, Temperature compensated
by water jacket and agent specific, can be used any where.
The accurate and precise delivery of ether irrespective of temperature
Advantages
Temperature compensation.
Reliable and generally safe.
Disadvantages
Bulky and heavy (it weighs 10 kg).
Requires high gas flow to deliver anaesthetic agents accurately.
The pumping effect of positive pressure ventilation may lead to dangerous
surges in volatile output.
Designed specifically for use with ether, which is now obsolete in the developed
world.
24. TEC - 2
Plenum type, concentration poorly calibrated, flow over with
wicks, temperature compensated, out of circle and agent specific.
25. TEC - 3
Plenum type, variable by pass, flow over with wicks, temperature
compensated, concentration calibrated, out of circle, agent
specific.
26. TEC - 4
Plenum type, variable bypass, flow over with wicks, temperature compensated,
concentration calibrated, out of circle, agent specific.
27. NEWER VAPORIZER
TEC 5
Plenum type, concentration calibrated, variable bypass, flow over with wicks,
out of circle, agent specific with keyed filling.
28. TEC - 7
Concentration calibrated, plenum type, Variable bypass, Flow over with wicks,
Temperature compensated, out of circuit, agent specific
▪ The latest model of the TEC series
▪ It delivers Isoflurane, Sevoflurane, Enflurane and
Halothane efficiently
▪ Accommodates 225 mL of anesthetic agent.
▪ Non-spill system limits movement of liquid agent
▪ if the vaporizer is tilted or inverted
▪ helping to protect internal components.
29. Advantages
• Easy to use and reliable.
• Properly calibrated modern variable bypass vaporizers are accurate to +/- 15% of the dial setting
for all flows between 200 ml.min-1 and 15 l.min-1 at 21°C.
• This type of vaporizer does not require a power source.
Disadvantages
• High internal resistance so must be used ‘out of circle’.
• The heat sink makes the vaporizer heavy – another reason why this type of vaporizer is not
suitable for use in the field.
• There are no alarms to indicate that the level of liquid anaesthetic inside the vaporizer is low.
• Temperature compensation only works within a reasonable range of ambient temperatures.
• If the vaporizer is used in an extremely hot or cold environment it will deliver anaesthetic
unreliably.
30. Problems of Desflurane
▪ Desflurane is much more volatile than all the other inhalationals.
▪ Its boiling point is low -- only 22.80 C, so most of it gets evaporated at normal room temperatures
▪ Vapor pressure of desflurane at 200 C is 664 mm Hg.
▪ While that of Enflurane, isoflurane, halothane are 172, 240, 244 mm Hg. respectively
▪ At 1 atmosphere and 200 C , 100mL/min flow passing through vaporizing chamber would carry
▪ 735 mL/min. of desflurane
versus
▪ 29, 46 and 47 mL/min of enflurane, Isoflurane and halothane respectively.
▪ Under these conditions to produce 1% of desflurane,
▪ we need 73 L/min Fresh Gas Flow
As compared
▪ to 5 L/min for other anesthetics, to pass through vaporizer
31. • In the above figure, note different vapor pressure-temperature relationships between common
volatile agents
• Desflurane falls outside the grouping
• Hence, Not surprisingly, special vaporizer is required for desflurane.
32. Specifically designed to deliver Desflurane
Described as a gas/vapor blender than as a vaporizer.
It is heated electrically to 350 C
Pressurized Device with a pressure of 1550 mmHg (2 atm)
Electronic monitors of vaporizer function
FGF does not enter vaporization chamber, instead Desflurane
vapor enters the path of FGF
Percentage control dial regulates flow of Desflurane into FGF
Dial calibration is from 1% to 18%
Provided with back up 9 volt battery
Datex-Ohmeda Tec 6 Vaporizers for Desflurane (1989)
33. The pressure in the vapor circuit is electronically
regulated to equal the pressure in the fresh gas
circuit.
At a constant fresh gas flow rate, the operator
regulates vapor flow by use of a conventional
concentration control dial.
When the fresh gas flow rate increases, the
working pressure increases proportionally.
At a specific dial setting, at different fresh gas
flow rates, vaporizer output is constant because
the amount of flow through each circuit is
proportional.
34. Advantages
• Comparable accuracy to variable bypass Tec 5 vaporizers; +/- 15% of dialled setting.
• Unaffected by ambient temperature because the desflurane is heated.
• Automatically compensates for variation in FGF.
• Has visual and audible alarms to alert the anaesthetist that the vaporizer is almost
empty or that there is no output.
Disadvantages
• Requires an electrical power supply.
• Requires time to warm up before it is operational.
Safety
• As with other Tec vaporizers, it is very difficult to fill the Tec 6 vaporizer with an
anaesthetic other than desflurane due to the key system for filling. There is also a
colour coding system that helps prevent filling of vaporizers with the wrong
anaesthetic.
• The Tec 6 design prevents desflurane liquid spilling into the FGF if the vaporizer is
tilted or inverted.
35. Schematic diagram of the TEC 6 vaporizer.
There are two mechanisms that govern the release
of desflurane vapour into the FGF.
1. The first is the dial that is located on top of the
vaporizer that is set to a desired concentration by
the anaesthetist.
2. The second is a valve that maintains the set
concentration, in response to changes in the FGF
(if the FGF increases then the rate of desflurane
release must also increase to maintain a constant
concentration). This is achieved by a differential
pressure transducer which compares the pressure
in the desflurane circuit with that in the FGF circuit.
When the FGF is increased, its pressure also
increases and this is detected by the transducer. A
microprocessor then opens the valve enough to
increase the amount of desflurane that is injected.
The opposite occurs when the FGF is reduced.
36. Aladin Cassette Vaporizer System
▪ A Novel system
▪ Single vaporizer capable of delivering 5 different anaesthetic
agents
▪ It is designed for use with Datex-Ohmeda S/5 ADU and similar
machines.
▪ FGF is divided into bypass flow and liquid chamber flow
▪ Liquid chamber flow conducted into agent specific, color coded
cassette in which volatile anesthetic is vaporized
▪ Machine accepts only one cassette at a time
▪ Magnetic Labeling
37. Advantages
• Automated recognition of the agent inserted.
• On-screen data showing agent levels and anaesthetic usage.
• Automated, electronically monitored and controlled FGF, temperature and pressure
compensation.
• No risk of spillage of anaesthetic agent into the bypass channel.
• Cassette can be carried safely in any orientation.
Disadvantages
• Specific to a particular branded anaesthetic machine.
• Anaesthetic delivery requires electrical power.
38. ▪ Similar to tec 4,5 vaporizers.
▪ The interlock on Dräger machines continues to function if any
vaporizers are removed.
▪ There is no outlet check valve - the tortuous inlet arrangement
protects from the pumping effect.
▪ No anti-spill mechanism.
▪ Should not be tipped more than 45.
DRAGER 19.1
39. Drager 2000
• Is one of two tippable vaporizers
(ADUcassettes are the other).
• The dial must first be rotated to a "T"
setting ("transport" or "tip") which is
beyond zero (clockwise).
• Tortous in let protects against pumping
effect.
40. Safety features
▪ Color specific (for each agent)
▪ Keyed fillers bottles
▪ Low filling port
▪ Vaporizers are locked into the gas circuit, thus ensuring they are seated correctly.
▪ Secured vaporizers Interlocks
▪ less ability to move them about minimizes tipping
▪ Only one vaporizer is turned on
▪ Trace vapor output is minimized when the vaporizer is off
▪ Concentration dial increases output in all when rotated counterclockwise.
41. Filling system
▪ Bottle Keyed System
▪ Funnel Fill System
▪ Keyed Filling System
▪ Quick-Fill System
▪ Easy-Fill System
▪ Desflurane Filling Systems
Quick fill system
42. FUNNEL FILL
▪ Vaporizers may be filled by a conventional
funnel-fill mechanism, in which the liquid
anesthetic is simply poured into a funnel in
the vaporizer.
▪ Complication is filling with wrong agent.
43. KEYED FILL
In this system, an agent-specific filler tube is
used, one end of which slots into a fitting on the
vaporizer, and the other end slots into a collar on
the bottle of anesthetic. The fitting on the
vaporizer and the collar on the bottle are specific
to each agent.
44. ▪ The bottle has a permanently
attached, agent-specific filling
device that has three ridges that fit
into slots in the filler.
QUICK FILL
45. EASY FIL
▪ A color coded bottle adaptor is attatched to
bottle and then fitted into the vaporizer.
▪ A drain plug is there for draining vaporizer.
46. Hazards
1. Incorrect Agent
2. Tipping
3. Overfilling
4. Reversed Flow
5. Control Dial in Wrong Position
6. Leaks
7. Vapour Leak into the Fresh Gas Line
8. Contaminants in the Vaporizing Chamber
9. Physical Damage
10. No Vapor Output
11. Projectile
47. Hazards
▪ Tipping
▪ If tipped >45 degrees-liquid can obstruct the outlet valves
▪ Treatment: Flush for 20-30 min at high flow rates with dial set at high
concentration
▪ Overfilling May result in high output
▪ Fill only up to max filling line
▪ Fill only when the vaporizer is off
▪ Leaks
▪ Relatively common due to malposition or loose filler cap.
▪ Not detected with standard checklist perform negative pressure check
48. Hazards
▪ Misfilling
▪ Vaporizers not equipped with keyed filling lead to misfiling.
▪ Contamination
▪ It occurs by filling a vaporizer with contaminated anesthetic bottle.
▪ Underfilling
▪ Leads to decreased vaporizer output.
▪ Simultaneous Inhaled Anesthetic Administration
▪ Happened in old machines with no interlock system
Draw over vaporizer - Sometimes called ‘vaporizer-in-circle/circuit’ or ‘VIC’, although in practice they are not used with circle systems.
plenum originates from the Latin for ‘full’ or ‘pressurized’.
Sometimes called ‘vaporizer-out-of-circle/circuit’ or ‘VOC’.
As anaesthetic liquid changes state and becomes a vapour, it absorbs heat from its surroundings, which provides the energy to break bonds between the liquid molecules. This energy is known as the latent heat of vaporization.
Copper was used for the housing of the vaporizer because it has both a high heat capacity and high thermal conductivity
you may see your local barista using a bimetallic strip thermometer to measure the temperature of the steamed milk.