General anesthesia HISTORY OF ANESTHESIA, ADVANTAGES AND DISADVANTAGES OF GENERAL ANESTHESIA, INDICATIONS AND CONTRAINDICATIONS OF GENERAL ANESTHESIA, PREOPERATIVE EVALUATION, PREANAESTHETIC MEDICATION, STAGES OF GENERAL ANESTHESIA, VITAL SIGNS, CLASSIFICATION OF GENERAL ANESTHESIA, ASA CLASSIFICATION, Isoflurane, Sevoflurane, Desflurane, Fentanyl , KETAMINE

1. General anesthesia
DR. DHARATI PATEL

2. Contents
• DEFINITIONS
• HISTORY OF ANESTHESIA
• ADVANTAGES AND DISADVANTAGES
• INDICATIONS AND CONTRA INDICATIONS
• PREOPERATIVE EVALUATION
• PREANAESTHETIC MEDICATION
• STAGES OF GENERAL ANESTHESIA
• CLASSIFICATION OF GENERAL ANESTHESIA
• ARMAMENTARIUM

3. Will be covered in next part …..
• GENERAL ANAESTHETIC AGENTS
• TECHNIQUES
• RECOVERY/DISCHARGE
• COMPLICATIONS OF GENERAL ANAESTHESIA
• CONCLUSION

4. Definition
• General anaesthesia is defined as controlled state of unconsciousness
accompanied by a loss of protective reflexes, inducing the ability to
maintain an airway independently and respond purposefully to
physical stimulation or verbal command.
• Also defined as an irregular, reversible depression of the higher
centres of the central nervous system (CNS) that makes the patient
unconscious and insensible to pain

5. History

6. • Ether - first described in 1540 by ‘Valerius Cordus’
• Used as anesthetic in 1842 by ‘Dr. W.E. Clark’ and ‘Dr.Crawford W. Long’
• First public demonstration of use of ether was in October 17, 1846 by
‘Dr. William T. G. Morton’
• ‘Morton’ - Successfully demonstrated properties of ether and named it as
‘Etherization’

7. William T.G. Morton’s Ether Inhaler

8. • 1847- ‘Simpson’ discovered use of Chloroform for Anesthesia
• 1935 – First IV anesthetic Thiopentone was introduced
• 1951- ‘C. W. Suckling’ of Manchester synthesized Halothane
• 1956 – ‘Michael Johnstone’ used Halothane clinically
J.Y.Simpson

9. General anesthesia represent ……
Muscle
relaxation
Analgesia
Unconscious
ness

10. Advantages
Success rate of 100%
Patient cooperation is not essential for the success of general
anesthesia
Patient is unconscious
Patient does not respond to pain
Amnesia is present
Onset of action of general anesthesia is usually quite rapid - <1 minute
Titration is possible

11. • The only technique that will prove successful for certain patients
 The un-cooperative child
 Extremely fearful adult
 Either physical or mental disabilities

12. Disadvantages
• Patient is unconscious
• Protective reflexes are depressed
• Vital signs are depressed
• Trained staff is required
• An “anaesthesia team” is required
• Special equipment is required
• Need for recovery room
• Intraoperative complications are more likely
• Post-anesthetic complications
• More extensive pre-op evaluation, including lab work

13. Indications
Extreme anxiety and fear
Adults or children who have mental or physical disabilities,
senile patients, or disoriented patients
Age—infants and children
Short, traumatic procedures
Prolonged, trauma

14. Indication in children
• Patient unable to cooperate – mental or physical disability
• When LA is ineffective – acute infection , anatomic variations, allergy
• Extremely uncooperative , fearful, anxious, physically resistant,
uncommunicative child
• In whom there is no expectation that the behavior will improve
• Patient who have sustained extensive orofacial or dental trauma and
require surgical procedure
• Patient requiring immediate comprehensive oral or dental needs
• Use of GA may protect the developing psyche and reduce medical
risks

15. Contraindications
Lack of adequate training by the dentist
Lack of adequately trained personnel
Lack of adequate equipment
Lack of adequate facilities
ASA 4 and certain ASA 3 medically compromised patients

16. Requirements as a dentist
• Dental residency of 1-4 year in a teaching hospital
• A rotation in which dental resident actively involved in administrating
GA
• Current certification in basic cardiopulmonary resuscitation
• Should be aware of hospital’s by laws, rules, regulations and meetings
• Should endeavor to provide the highest quality care

17. Evaluation of the hospital…
• Membership of other dentists on the hospital staff
• Positive attitude of the hospital staff
• Attitude of staff physicians toward dental treatment
• Experience of anesthesiology staff
• Availability of consulting physician
• Hospitals regulations
• Availability of operating room time
• Availability of patient bed
• Availability of dental equipment
• Convenience of the location of hospital

18. Two general categories
Young children who
need extensive
treatment and
unmanageable as
outpatient
Children with
mental or physical
disabilities
Admission justification

19. Pre - admission preparation
• A dentist’s decision to treat a child under GA – approved by the
child's parents
• Dentist's responsibility – increased risk and expense
• Must evaluate the child’s psychological state
• An information page should be provided to parents
• Necessity of having both or one parent prior to GA when the child
awakens
• For mentally or physical handicapped child – will require special
control techniques and ensure they will be available
• Child’s physician should prescribe special diet or pre-medicaments

20. • Dentist should make proper plan for hospitalization
• Operating room must be scheduled
• Arrangements must be made for an anesthesiologist
• Physical examination – one day prior by physician
• Should Assess general health (ASA Classification)
• Ask for Drug history

21. ASA Classification
ASA I Normal healthy patient
ASA II Patient with mild systemic disease
ASA III Patient with severe systemic disease that is limiting but
not incapacitating
ASA IV Patient with incapacitating disease which is constant
threat to life
ASA V Moribund patient not expected to live more than 24
hours
ASA VI A declared brain dead patient whose organ are being
removed for donor purposes

22. Admission letter
to parents before
two weeks

23. Medical history and
Physical examination

24. Pediatric history
Identification
• Age
• Sex
• Racial-ethnic profile
History of present illness
Medical survey
• Immunization
• Previous hospitalization
• Allergies
• Dietary history
• Current medications
Developmental status
Family history

25. Physical examination
Vital signs
• Pulse rate
• Respiration rate
• Blood pressure
• Temperature
Measurements
• Weight
• Height
General appearance
• Nutrition
• Colour
• Distress

26. Head
Eyes – pupils and extraocular movements
Ears
Nose – patency and secretion
Neck
Lungs
Cardiovascular system – heart sounds , rate , rhythm , murmurs
Abdomen
Genitalia
Lymph nodes
Skeleton nervous system

27. Vital signs

28. Heart rate and Respiratory rate

29. Blood pressure

30. Temperature
°F 0-2 years 3-10 years 11-65 years > 65 years
Oral - 95.9-99.5 97.6-99.6 96.5-98.5
Rectal 97.9-100.4 97.9-100.4 98.6-100.6 97.1-99.2
Axillary 94.5-99.1 96.6-98 95.3-98.4 96.0 – 97.4

31. Dental history and
Intra-oral examination

32. Past dental history
Behavior
Past
experience
Treatment
done
Head and neck
General
Head
Neck
Face
Lateral facial
profile
Intra oral examination
Lips
Tongue
Floor of the
mouth
Buccal
mucosa
Hard and
soft palate
Teeth
Caries
Eruption
sequence
Occlusion
Overjet
Overbite
Midline
Oral habits

33. Pre – operative
investigation

34. Patient undergoing surgery should be screened for…..
 Biochemical
 Hematological
 Radiological abnormalities
 ECG

35. Consent

38. Signature required
• If the patient is adult
 signature of patient
 If the patient is incompetent – the guardian’s signature
• Minor patient (under 18 )
 If emancipated – patient’s signature
 Signature of parent or guardian is required
• In an emergency/life threatening situation - signatures as above
are not available……
 Signature of two physician
 Signature of closest adult

39. Admission to the
hospital

40. • Child is usually admitted on the day before treatment and have to
stay till next morning
• Parents should complete the necessary forms
• Dentist should give the admission order which include
 Order for NPO(nothing by mouth )
 Order for specific drug and specific dosage
 Preoperative sedation orders
 Request for the child to be transferred to the operating room

41. Admission order

42. • Nursing staff should explain – standard hospital procedure to
parents
• Child will be visited by anesthesiologist
• The decision regrading nothing by mouth - determined by
anesthesiologist
• Dentist should evaluate pre-operative laboratory data
• Dentist should collect admitting note
• And record preoperative note
• 30 minute before dentist and staff should be in operating room
area

43. Admitting note
• Provides general information about the child and reason
for admission
• This form is given to child's physician
• The physician have to enter preoperative physical
examination and return it

45. Nothing by Mouth
nil per os (NPO)

48. In general …

49. Operative room protocol
• Must follow OSHA guidelines
• Must wear – surgical suite
• Eyeglasses, nose hood , face shield and mouth mask
• Should follow standard scrubbing method
• Avoid cross-contamination between patient in the
hospital

50. Universal protocol
checklist
When patient enters the operating room the mandatory
“ TIME OUT PROTOCOL” initiated by the nurse

53. Operating room

54. Pre- Anesthetic Medication
• Relief of anxiety and apprehension preoperatively and facilitate
smooth induction
• Supplement analgesic action of anesthetics and potentiate them so
that less anesthetic is needed
• Decrease secretions and vagal stimulation caused by anesthetics
• Produce antiemetic effect extending to the postoperative period
• Decrease acidity and volume of gastric juice so that it is less
damaging if aspirated

56. Stages of General Anesthesia
• Guedel - 1920
• Observations on the following parameters
 Character of respiration
 Eyeball activity
 Pupillary changes
 Eyelid reflex
 Swallowing and vomiting

57. I. Stage of Analgesia
starts with the initial administration of a CNS-depressant drug and
continues to the loss of consciousness
1. Respiration is normal
2. Eye movements are normal, with voluntary movement possible
3. Protective reflexes are intact
4. Amnesia (the lack of recall) may or may not be present
5. Diminished intellect, memory, integrative functions, perception of
time and space

58. II. Stage of Delirium
begins with loss of consciousness and progresses until entry into the
stage of surgical anaesthesia (stage III)
• Respirations are irregular early in stage II, but become more regular as
stage II deepens
• Eyeballs oscillate involuntarily, a movement termed Lateral nystagmus
• Pupils react to light normally
• Skeletal muscle tonus is increased, with muscular rigidity present in
some patients early in stage II.

59. • Muscle tonus decreases as stage II deepens.
• The laryngeal and pharyngeal reflexes (swallowing and laryngeal
closure) are still quite active early in stage II, but become
progressively more obtunded as stage II progresses.

60. III. Stage of Surgical Anesthesia
Entry into stage III is marked by several signs and divided into 4
planes :
Plane 1 :
• Respiratory regularity equally Thoracic and abdominal
• Eyeballs oscillate slowly & pupils respond normally to light
• Swallowing and vomiting reflexes disappear
• Tears secreted
• Tendency to breathe deeply and rapidly with skin incision decreases
• Peripheral vasodilatation

61. Plane 2 :
• Eyeballs cease to oscillate
• Intercostal muscles weaken.
• Respiration regular but tidal volume is decreased
• Pupil size increases
• Laryngeal reflexes diminishes
• Tears secretion decreased
• Respiratory response to skin incision disappears

62. Plane 3 :
• Pupillary response to light is abolished
• As plane deepens intercostal paralysis
Plane 4 :
• Complete intercostal & diaphragm paralysis
• Pupils dilate and no muscle tonus

63. Stage IV : Medullary paralysis
• Begins with onset of respiratory arrest and ends with cessation
of effective circulation.

65. Types of General Anesthesia
1. In-office outpatient general anesthesia
1. IV anesthesia (Propofol or barbiturates) (less than 30 minutes)
2. Conventional operating theater type of general anesthesia(more
than 30 minutes and less than 4 hours)
2. Inpatient general anesthesia

66. In-office outpatient
general anesthesia

67. Intravenous Propofol or Barbiturates
• IV Propofol or barbiturates are highly accepted and common - to induce
and maintain unconsciousness in GA
• Known as ultralight general anesthesia
• May receive other drugs - nitrous oxide-oxygen (N2O-O2),
benzodiazepine and opioids
• The administration of O2 minimizes the risk of hypoxia.
• Local anesthesia is important.

68. Conventional Operating Room Type of GA
• A variation of outpatient general anesthesia is used in - procedure 30
minutes to 4 hours or longer
• Same preparation and procedure as does the inpatient
• Limited to the ASA 1, ASA 2, and selected ASA 3 patients
• A dentist will be responsible for the dental care
• In no circumstance should the same person administer the general
anesthetic and perform the dental treatment
• The duration of an outpatient general anesthetic not exceed - 4 hours

69. Inpatient General Anesthesia
• This patient is admitted to the hospital before the planned procedure
• Undergoes the procedure then remains in the hospital at least 1 day
postoperatively
• The dentist need not be trained in anesthesiology
• The anesthesiologist is responsible for the administration of the
anesthetic
• In prolonged dental treatment - the dentist will request that the patient
be intubated through the nose (nasoendotracheal) rather than through
the mouth (oroendotracheal)

70. • The administration of general anesthesia for dental procedures is
more difficult
• Because the oral cavity is the treatment zone
• Therefore the potential for airway complications is increased
• Mortality rates for hospital inpatient anesthesia > outpatient
procedures
• ASA 1 and 2 patients are treated as outpatients
• ASA 3 and 4 patients are usually hospitalized

71. Armamentarium

72. Anesthesia
machine
IV
equipment
Ancillary
anesthesia
equipment
Pharyngeal
throat pack
Monitoring
equipment
Emergency
equipment

73. Anesthesia Machine
• Able to deliver oxygen (O2) and inhalation anesthetics to the patient.
• The inhalation sedation (n2o o2) is a modification of the anesthesia
machine
• The anesthesia machine can deliver many gases: N2O, O2,
sevoflurane, desflurane, and isoflurane.
• Flowmeters and devices called vaporizers that contain the various
volatile anesthetics and permit their concentrations to be controlled

74. • The anesthesia machine is capable of operating with O2 and N2O
supplied from cylinders
• Anesthesia machines have O2 monitors that sound an alarm - if the
unit fails to provide a preset minimum percentage of O2 (i.E., 25%)
• Ventilator - a device used to control or assist the ventilation of a
patient during anesthesia - attached to the right side

76. • The modern anesthesia machine contains a number of
important devices for monitoring patients
 A blood pressure monitor
 Electrocardiograph (ECG)
 Pulse oximeter
 Capnograph (end-tidal carbon dioxide [ETCO2] monitor)
 Bispectral (BIS) electroencephalograph (EEG) monitor

77. Intravenous equipment
• Winged needles (18 gauge )
• Indwelling catheters
• Tubing and bags of IV solution (1000 ml)
• Disposable syringes and needles
• Adhesive tapes (paper, hypoallergenic)

78. Ancillary Anesthesia
Equipment

79. Full-face masks - sizes and appropriate connectors
Laryngoscope
Endotracheal tubes and appropriate connectors
Laryngeal mask airway (LMA)
Oropharyngeal and nasopharyngeal airways
Tonsillar suction tips
Magill intubation forceps
Child- and adult-size sphygmomanometers
Stethoscopes

80. Face mask
• Rubber or silicone masks
• Cover both the mouth and nose of the patient
• Face masks are - deliver O2, N2O-O2 and other inhalation
anesthetics before, during and after the anesthetic procedure
• Made from a clear plastic or rubber
• Metal connectors - attach the face mask to the tubing of the
anesthesia machine - variety of sizes and shapes

82. Laryngoscopes
• Designed to assist in the visualization of the trachea during intubation
• It consists of two parts
 A handle and battery holder
 Blade
• The handle – made of metal and contains batteries (used to operate
the light bulb found in the blade)
• The blade - made of metal
• The laryngoscope blade - designed to aid in visualization of the larynx
• A small light bulb that illuminates the laryngeal area is attached to
the blade

84. • There are two basic types of laryngoscope blades
 The curved (Macintosh) - commonly used
 The straight (Miller) blade
• Available in a variety of sizes
• The tip of the curved blade is inserted into the vallecular
• Blades are designed to be held in the operator’s left hand
• With the endotracheal tube held in the right hand

86. Technique
The tip of the curved blade is inserted into the
vallecular - between the base of the tongue and the
epiglottis
The handle of the laryngoscope is then lifted
straight up and slightly forward - a movement
that visualizes the vocal cords
When a straight blade is used its tip is placed
underneath the laryngeal surface of the epiglottis
The larynx is exposed by an upward and forward
lift of the blade

87. Endotracheal Tubes and Connectors
• Endotracheal tubes and connectors are rubber tubes designed to be
placed from the mouth (oroendotracheal) or nose (nasoendotracheal)
into the patient’s trachea.
• Reusable and disposable
• Endotracheal tubes have an inflatable cuff located near their distal
ends
• Connectors for endotracheal tubes = used for full-face masks
 Used to connect the endotracheal tube to the anesthesia machine

89. When a patient is intubated
the endotracheal tube is inserted into the
trachea so that the uninflated cuff disappears
just beyond the level of the larynx.
Air is then injected into a tube to inflate the
cuff
Enough air is injected into the cuff to seal the
trachea

91. DEPTH OF ENDOTRACHEAL TUBE
• Adult
 Male = 23 cm
 Female = 21cm
• Children
 Oral endotracheal tube = (Age / 2) + 12(cm)
 Nasal endotracheal tube = (Age / 2) + 15(cm)

92. Size of endotracheal tube Internal diameter (ID)
Male 8.0 mm
Female 7.5 mm
New born – 3 months 3.0 mm
3-9 months 3.5 mm
9-18 months 4.0 mm
2-6 yrs. (Age/3) +3.5
>6 yrs. (Age/4) + 4.5

95. Advantages of endotracheal
intubation
• Free unobstructed airway
• Ventilation can be controlled or assisted
• aspiration of blood, mucus, vomitus into lung is
prevented
• Measured amount of gases and vapors can be delivered
• Safe and acceptable
• Dead space can be managed

96. Disadvantages
• Need of expertise
• Injury to teeth, lips, larynx, epiglottis, pharynx or trachea
• Cost

97. Complications of
intubation

98. When Intubated
• Obstruction from klinking , secretion or over-inflation of cuff
• Accidental extubation or endobronchial intubation
• Disconnection from breathing circuit
• Pulmonary aspiration
• Lip or nasal ulcer in case with prolong period of intubation
• Sinusitis or otitis in case with prolong Naso-endotracheal
intubation

99. During Intubation
• Trauma to lip , tongue or teeth
• Hypertension and tachycardia or arrhythmia
• Pulmonary aspiration
• Laryngospasm
• Bronchospasm
• Laryngeal edema
• Spinal cord trauma in cervical spine injury
• Esophageal intubation

100. Complications of
extubation

101. During
Extubation
Laryngospasm
Pulmonary aspiration
Edema of upper airway
After Extubation
Sore throat
Hoarseness
Tracheal stenosis
(Prolong intubation)
Laryngeal granuloma

102. Oropharyngeal and Nasopharyngeal Airways
• Oropharyngeal and nasopharyngeal airways - used to assist in
maintaining a patent airway during and after the anesthetic procedure
• Plastic, rubber or metallic devices
• Designed to lie between the base of the tongue and the posterior
pharyngeal wall
• The nasopharyngeal airway - better tolerated by the conscious or
sedated patient
• Nasal airways should be lubricated

104. Oral airway Nasal airway Oral airway Nasal airway

105. Tonsillar Suction Tips
• Excessive salivation , bleeding in the mouth or pharynx, or vomiting -
can lead to airway obstruction, laryngospasm, or possible infection of
the trachea or bronchi
• Tonsillar suction tips are recommended
….. because they can be inserted blindly into the posterior pharynx of
the patient with minimal risk of producing bleeding
• The end of the tonsillar suction tip is rounded
• Several tonsillar suction tips should be available

106. Tonsillar Suction Tips

107. Magill Intubation Forceps
• Designed to assist in placing the endotracheal tube
• It is most frequently used during nasoendotracheal
• It is L shaped and has no catch
• It is available in 2 sizes : adult and pediatrics

109. Pharyngeal throat pack
• Pharyngopalatine area should be sealed off
• With a strip of moist sterile gauze piece
 Width – 3 inches
 Length – 18-20 inches
• Written documentation of throat pack placement is
necessary
• Reduce the escape of anesthetic agents and prevent any
material entering the pharynx
• Gauze should tightly pack around the tube – good seal

110. Sphygmomanometers and Stethoscopes
• Must available during GA procedures
• Used for the monitoring
 Vital signs
 Specifically blood pressure
 Heart rate and rhythm
 Heart sounds
 Breathes sounds

111. Monitors
ECG Pulse Oxymeter
Pretracheal
stethoscope
Capnograph

112. Emergency Equipment

113. Emergency Drugs….
Vasopressor Corticosteroid Bronchodilator Muscle relaxant
Appropriate
drug
antagonist(s)
Antihistaminic Anticholinergic Antiarrhythmic
Coronary artery
vasodilator
Antihypertensiv
e
Anticonvulsant
O2 and 50%
dextrose

114. Emergency Equipment
• Backup lighting system
• Backup suction device
• O2 delivery system
• Laryngoscope with complete selection of blades and spare
batteries and bulb
• Endotracheal tubes and appropriate connectors
• Oral airways

115. • Tonsillar or pharyngeal type suction tip
• Endotracheal tube forceps (Magill intubation forceps)
• Sphygmomanometer and stethoscope
• Electrocardioscope and defibrillator
• Adequate equipment for the establishment of an IV infusion
• Precordial or Pretracheal stethoscope
• Pulse oximeter

116. Agents used for GA
Inhalation
Intravenous

117. Inhalation
Gas Nitrous oxide
Liquid
Ether
Halothane
Enflurane
Isoflurane
Desflurane
Sevoflurane

118. Intravenous
Inducing
agents
Thiopentone
sodium
Methohexitone
sodium
Propofol
Slower acting
agents
Diazepam
Lorazepam
Midazolam
Dissociative
anesthesia
Ketamine
Neuroleptic
analgesia
Fentanyl

119. Ether
• Highly volatile – liquid
• Vapor – irritating , inflammable and explosive
• Potent anesthetic – good analgesia and muscle relaxation
• Highly soluble in blood
• Induction – prolonged and unpleasant
• Atropine must – as premedication
• Recovery – slow
• Post anesthetic nausea , vomiting and retching

120. Halothane
• Halogen substituted ethane
• Volatile liquid – sweet odor , nonirritant and nonflammable
• Solubility in blood – intermediate
• Induction – quick and pleasant
• Potent inhalational anesthetic
• Dose: For induction 2-4%, Maintenance 0.5-1%
• Not good analgesic nor muscles relaxant

121. • Cause direct depression of myocardial contractility
• Cardiac output , blood pressure ,heart rate – decreased
• Breathing – shallow and rapid
• Pharyngeal and laryngeal reflexes are abolished early
• Coughing – depressed and bronchi – dilated
• Inhibits – intestinal and uterine contractions

122. • 20 % halothane enters to blood is metabolized in liver
• The rest is exhaled out
• Recovery – smooth and reasonably quick
• Shivering , nausea , vomiting – may occur

123. Halothane side effects
• Halothane hepatitis” -1/10,000 cases
• Malignant hyperthermia - 1/60,000 with succinylcholine to
1/2,60,000 without succinylcholine
• Clinical feature - rapid rise in body temperature, muscle rigidity,
tachycardia, acidosis, hyperkalemia

124. Isoflurane
• Fluoridated anesthetic
• Similar to halothane
• Less soluble in blood
• Respiratory depression – prominent
• Secretions – slightly increased
• Post anesthetic nausea and vomiting – less
• Slightly irritating
• Does not provoke seizures

125. Desflurane
• Less potent than isoflurane
• Higher concentration has to be use
• Irritates air passage
• Pharmacological properties – same as isoflurane
• Good alternative for isoflurane – prolonged operations

126. Sevoflurane
• Properties – intermediate between isoflurane and
desflurane
• Induction – fast and rapid
• Pleasant - acceptability good by pediatric patient
• Suit for both – inpatient and outpatient
• Expensive

127. Intravenous agents
Loss of consciousness – 11 sec
Used for induction – rapid onset
Maintained by – inhalation agents

128. Thiopentone sodium
• Ultrashort acting – Thiobarbiturate
• Highly soluble in water yielding a very alkaline solution
• Must be prepare freshly
• Dose – I.V 3-5 mg/kg – 15-20 seconds
• Has high lipid solubility – enters in to brain instantly
• Consciousness regained in 8-12 minute
• t1/2 of distribution – 3 minute

129. • Elimination t1/2 – 7-12 hr.
• Poor analgesic
• Weak muscle relaxant
• BP falls immediately – due to vasodilation – but recovers rapidly
• Employed as sole anesthetic – short operation –not painful
• Adverse effect
 laryngospasm while intubation
 Shivering and delirium while recovery

130. Propofol
• Oily liquid
• 1% emulsion for I.V. induction
• Unconsciousness occurs – 15-45 seconds
• Distribution t1/2 – 2-4 minute
• Elimination t1/2 – 100minute
• Particularly suited for outpatient G.A
• Fall in blood pressure – vasodilation
• Bradycardia – frequent
• Dose – 2.4 mg/kg/hr.

131. Ketamine
• Induces dissociative anesthesia
 Profound analgesia
 Immobility
 Amnesia
 Light sleep
 Dissociated from own body and surroundings
• Primary site of action – in the cortex and subcortical areas
• Respiration – not depressed
• Airway reflexes – maintained
• Muscle tone – increased

132. • Heart rate , cardiac output and blood pressure – are elevated
• Recovery within – 10-15 minutes
• Remains amnesic – 1-2 hr.
• Injection is not painful
• Children tolerate drug better
• Elimination t1/2 – 3-4 hr.
• Good for repeated use
• May be dangerous for hypertensive and IHD
• Good for hypovolemic patients

133. Indications
• Has been employed for dental and other operation of head and neck
• Asthmatic patient who do not want to lose consciousness for short
operation
• Combined with diazepam
 Angiography
 Trauma surgery
 Cardiac catherization

134. Fentanyl
• Short acting potent opioid analgesic
• Given I.V. at the beginning of painful surgical procedures
• Used as supplement anesthetics in balanced anesthesia
• Dose – 2-4 µg/kg
• After administration – patient remains drowsy but conscious
• Pt may be encourage to breath and assistance may be provide
• Nausea , vomiting and etching – during recovery

135. Techniques

136. In patient general anesthesia
• Used in dentistry for the more severely medically compromised patient (ASA
3 or 4) 0r patients undergoing extensive treatment
• Patient admitted a day before or early in the morning
• Pre-operative evaluation – done a day before
 Heamatocrit
 Haemoglobin
 CBC
 Differential count
 Urine analysis
 Chest x-ray and ECG – in adults and medically compromised patients

137. • Give written pre-operative instructions
• Anesthetist should visit the patient for Preanaesthetic visit
 Evaluate patient for special risks (potential airway maintenance
problems)
 Review physical examination and results of lab test
 Discuss anesthetic procedure – to allay apprehension
 Review Preanaesthetic orders – fasting instruction – NBM before 8 hours
 Administer pre-operative medication – anti-anxiety (diazepam) and
anticholinergic (atropine) – IM 1 hour before or IV in the operating table

138. • On the operating table
 Attach physiologic monitors – blood pressure cuff, a precordial
stethoscope, ECG, pulse oximeter, capnograph
 Establish IV infusion – indwelling catheter, not smaller than 18
gauge
 Cases requiring blood transfusion – catheter of 16-gauge
 Attach 1000 ml bag of normal saline or Ringer’s lactate to
maintain infusion

139. Induction of anesthesia
 Administer small dose of benzodiazepine to induce sedation
 Apply topical anesthetic on nostrils – for analgesia and hemostasis during
intubation
 Place full face mask on the patient with flow of 5 to 7 L min of 100% O2
 Administer Propofol until patient loses consciousness
 ‘Bag’ the patient confirming the airway is patent
 Administer depolarizing muscle relaxant – succinylcholine
 Non-depolarizing muscle relaxant may be administered to prevent
fasciculation.
 Lubricate endotracheal tube and place into nostril -> advance into nasopharynx

140.  Use laryngoscope – visualize larynx and tip of tube
 Using Magill’s intubation forceps – advance and insert the tube in larynx
 Attach endotracheal tube to anesthesia machine and ventilate the patient
 Administer drugs for maintenance of anesthesia – sevoflurane or IV
meperidine
 Adjust gas flow of machine – 3 L/min of N2O and 2 L/min of O2
 Inflate cuff of endotracheal tube – auscultate chest to check proper
intubation
 Drape the patient & prepare for surgery

141. • Anesthetist administers additional doses during procedure
• Administer LA for all dental procedure - for hemostasis and pain
control
• For additional muscle relaxation – administer neuromuscular
blocking agent – vecuronium or atracurium

142. • At the termination of procedure,
 Stop administration of inhalation anesthetics – administer 100% of
O2 or combination of N2O-O2 followed by 100% of O2
 In case of IV opioids, benzodiazepines and muscle relaxants –
administer additional drugs to reverse their actions
 Naloxane – to reverse opioid induce respiratory depression
 Flumazenil – for residual benzodiazepine action
 Anticholinesterase – to reverse muscle relaxation

143.  Patient will emerge from anesthesia
 Suction the pharynx before extubation
 When respiratory movements seem adequate, extubate the
patient after deflating the cuff
 Place the face mask and administer 100% O2

144. • Transfer the patient to recovery room
• Administer O2 via nasal cannula
• Monitor BP, pulse, respiration and ECG
• Patient is discharged after he/she is stable.

145. Ambulatory GA
• Drugs used are short acting to permit a more rapid and complete recovery
at the end of procedure
• Inhalational anesthetics used
• Written preoperative instruction of NBM of atleast 6-8 hours
• Basic lab test done and results obtained
• Complete physical examination done
• IM pre-medication not preferred.

146. Procedure
• Patient placed on operating table
• Place all monitoring devices on the patient
• Obtain IV line with 18 gauge indwelling catheter – using NS or
ringer’s lactate
• Induce anesthesia with IV Propofol, Iv midazolam and fentanyl or
with inhalational sevoflurane
• Muscle relaxants used rarely
• If intubation is desired, low dose of succinylcholine administered
• Once GA is induced, airway maintained with combination of N2O-O2
and appropriate inhalation anesthetic

147. • Place gauze or curtain in posterior part of pharynx
• Administration of LA desirable
• At the termination of procedure, 100% O2 is administered
• Patient taken to recovery room – 1 hour of recovery period is
recommended
• Patient discharged after adequate recovery
• Possibility of hospitalization may be explained in case of inadequate
require.

148. Intravenous GA
• Short procedures – requiring less than 30 minutes – short acting
drugs such as Propofol, midazolam or fentanyl used
• Establish IV line using 21 gauge catheter and 500-ml of suitable
infusate
• Small dose of Propofol, methohexital or thiopental is administered IV
• Bite block placed in-between patient’s teeth
• IV anesthetic titrated slowly until loss of consciousness
• Airway must be maintained
• Continued administration of Propofol is necessary to maintain level of
GA

149. • Infusion pumps are used to regulate administration of short acting
drugs
• LMAs are used frequently to maintain a patent and clean airway
• In case of open airway, a lubricated nasopharyngeal airway in
inserted into nares to assist in managing airway.
• Throughout the procedure, the patient receives ether 100% O2 or
combination of N2O- O2
• Administration small IV doses of benzodiazepines smooth out the
anaesthetic

150. • Administration of Propofol alone or with remifentanil via infusion
pumps help maintain a constant level of CNS depression
• Throat pack placement necessary
• LA administration recommended
• Return of consciousness is quite rapid, permits immediate removal of
LMA
• Patient have stable vital signs, patent airways and are responsive to
verbal commands in 5-15 minutes
• Patient discharged when stable

151. Reversal of anesthesia
• The only component - effect of the non depolarizing muscle relaxant.
• The timing of the last dose of the muscle relaxant is important and if it is too
near to the conclusion of surgery, adequate time must be allowed before
reversal is attempted.
• Non depolarizing muscle relaxant is reversed by anti choline esterase drugs
 E.G. Neostigmine sulphate (0.05- 0.07 mg/ kg).
• Atropine sulphate (anticholinergic) is given along with this to prevent the
muscarinic effects of neostigmine like bradycardia, profuse salivation and
bronchospasm.

152. Dental Consideration

154. Completion of the
procedure

155. • Notify anesthetist before 10 min of completion.
• Notify recovery room personnel
• Debride oral cavity after completion.
• Remove throat pack – prevent aspiration.
• The dentist should remain in the operating room during the
extubation process to assist the anesthesiologist if necessary
• When the child is transported to the recovery room the dentist
should accompany the anesthesiologist and provide assistance during
the transportation.

156. Discharge from
recovery

157. • Responsibility for the discharge process is shared between the dentist,
the anesthetist and the recovery nursing staff.
• Patients and parents should receive verbal and written post-operative
instructions
• Advice should be given of any symptoms that might be experienced in
the first 24 hours following discharge.
• Analgesics including paracetamol should be recommended for use in
the 24 to 48 hours following discharge.
• Specific instructions regarding mouth care after surgery should be
given.
• The nature of any sutures placed should be described and an
appointment made for post-operative assessment

158. • Conscious level should be consistent with the child’s preoperative state
• Cardiovascular and respiratory parameters should be stable
• Scoring systems exist to aid in the assessment of recovery
• Pain, nausea, vomiting and surgical bleeding should be minimal
• Mobility should be at a preoperative level
• A responsible adult must be present to accompany the child home
• Suitable transport home should have been arranged

159. • Contact telephone numbers should be provided for both emergency and
continuing care
• Verbal and written instructions about the child’s recovery at home should
be given to the parent / carer, with confirmation of the level of
understanding
• Follow‐up arrangements should be made where appropriate
• Support and guidance on the administration of medication at home
should be provided as necessary
• A letter to the General Dental Practitioner should be posted or given to
the parent / carer, depending on the policy of the unit
• Suitable home environment, with regard to supervision of the child as
well as access to further healthcare services, if required

160. Complication of GA

161. • Postoperative nausea and vomiting
• Respiratory
• Cardiovascular
• Anaphylaxis
• Delayed recovery from anesthesia
• Malignant hyperthermia

162. Conclusion
• Preanaesthetic evaluation – vital for success!
• Vigilant monitoring – prevent untoward complications
• Whichever method of induction or intubation is planned problems may
be encountered which will alter strategy.
• A good and sound knowledge about C.P.R and Emergency Medicine is
not only invaluable but essential
• A multidisciplinary team approach of a surgeon and anesthetist must
utilize well tried and tested protocols to minimize the complications

163. References
• Avery D R, McDonald R E.Dentistry for the child and Adolescent. Mosby,
9th Edition 2012 , 253-76
• Malamed SF: Rectal sedation. In Malamed SF: Sedation: a guide to patient
management, ed 4, St Louis, 2002, Mosby
• Alan R. Aitkenhead, Graham Smith. Textbook of anesthesia , edition 6 ,
Churchill Livingstone/Elsevier, 2007
• Pallasch TJ: Pharmacology for dental students and practitioners,
Philadelphia, 1980, Lea & Febiger.
• Trieger NT: Pain control, ed 2, St Louis, 1994, Mosby
• American Dental Association, Council on Dental Education: Guidelines for
the use of sedation and general anesthesia by dentists, as adopted by the
Oct 2007 ADA House of Delegates, Chicago, 2007

164. Thank you