Basics of Seadation & GA in oral and maxillofacial surgery

1. Sedation & General
Anesthesia In Maxillofacial
Surgery
STPHMMC
Presenter: Dr.FUAD M. ( OMFS-R2)
Moderator: Dr.BIRUKTAWIT (OMFS
Consultant) November,2011 E.C

2. Objectives
STPHMMC2
To give a brief revision & discuss about;
Historical background of Sedation & GA
Pre-anesthetic Evaluation & Preparation
Sedation on omfs
GA on omfs
Specific Anesthetic agents
Complications of GA

3. Outline
STPHMMC3
1. Part one
I. Introduction & History
II. Specific Anesthetic Problems In Omfs
III. Preanesthetic Evaluation
IV. Preoperative Preparation & Premedication
2. Part 2
V. Sedation In Omfs
VI. GA In Omfs
VII. Mechanism of Anesthesia
3. Part 3
VII. Specific Anesthetic Agents
4. Part 4
VIII. Complications Of GA
IX. References

4. STPHMMC4
Part 1
I. Introduction & History
II. Specific Anesthetic Problems In Omfs
III. Preanesthetic Evaluation
IV. Preoperative Preparation & Premedication

5. INTRODUCTION
STPHMMC5
 Pain and anxiety control, using various
techniques of regional anesthesia, sedation, and
general anesthesia
 Anxiety, fear, and pain are concerns because
each is inherent in the patient's reaction to the
proposed treatment.

6. INTRODUCTION
STPHMMC6
 The selection of a particular technique for
controlling pain and anxiety during has to be
individually determined for each patient,
considering the risks and benefits for each case.

7. HISTORY
STPHMMC8
 Ancient time-alcoholic and various herbals used
to induce sleep
 In the middle of the nineteenth century, bromide
was introduced specifically as a sedative-hypnotic
 1845-Horace Well- N2O
 1846-William Morton-ether
 1847-James Simpson-chloroform-induced general
anesthesia in surgery was pioneered in the USA
and UK

8. HISTORY
STPHMMC9
 1903 & 1912 - barbital and phenobarbital
respectively , dominant sedative-hypnotics
 1930’s, Dr. John Lundy, IV pentothal anesthesia
 1934-Thiopenton
 1956-halothane

9. Specific Anesthetic problems in
OMFS
STPHMMC10
 Shared airway.
 Muscle relaxation.
 IMF and throat pack:.
 Sepsis & Secretions
 Vagal stimulation
 Neck arthropathy
 Neck spaces:
 NG intubation
 Tracheostomy or surgical airway preparation :

10. Preanesthetic Evaluation
STPHMMC11
 Purpose Of Preoperative Preanesthetic
Evaluation
1. To obtain pertinent information about the
patient’s medical history and physical as well as
mental condition.
2. To determine the need for a medical
consultation and investigations
3. To educate the patient about anesthesia,
postoperative care, treatment of pain.
4. To choose the anesthetic plan to be followed,
guided by the risk factors uncovered by medical
history.

11. Preanesthetic Evaluation
STPHMMC12
Routine Preoperative Anesthetic Evaluation
 History
 Medical Problems
 Medications Used
 Allergy
 Smoking
 ROS;CVS,RS,CNS,GIS,
RENAL,HEPATIC,
HEMATOLOGY,
MS,REPRO..

12. Preanesthetic Evaluation
STPHMMC13
 Physical Examination
 It includes:
1. Vital signs
2. Airway
3.Cardiovascular
4. Respiratory
5.Gastrointestinal
6. Hepatic and Renal
7.ASA physical status scale
 Laboratory Tests

13. Preanesthetic Evaluation
STPHMMC14
Airway
 Is critical when determining an anesthetic plan
 Any abnormalities that might impair airway
management
- severe obesity - short neck - small
mandible
- large tongue - trismus - children/infants
 Consider assessments such as;
- Mallampati scoring
- Thyromental distance

14. STPHMMC15

15. Preanesthetic Evaluation
STPHMMC16
Cardiovascular
 Assess for disturbances in rhythm or other
abnormalities.
 In patients with known cardiovascular disease,
evaluate their degree of reserve because most
anesthetic agents can cause vasodilatation and
hypotension.
Respiratory
 Perform lung auscultation ;pulmonary disease
,URTI
Gastrointestinal
 Time and nature of the last oral intake

16. STPHMMC17

17. Preanesthetic Evaluation
STPHMMC19
Hepatic and Renal
 The implications of delayed metabolism or excretion
of anesthetic agents in infants younger than 6
months, in the elderly, and in patients with hepatic or
renal abnormality should be considered

18. Preanesthetic Evaluation
STPHMMC20

19. STPHMMC22

20. Preoperative Anesthetic Preparation and
Premedication
STPHMMC23
 The basic plan of preoperative preparation is as
follows:
A. Patient’s counseling or psychological preparation
B. Premedication
C. Preoperative instructions for
• Fasting guidelines,
• Administration of current medication or
preexisting drug therapy

21. STPHMMC24

22. STPHMMC25

23. STPHMMC26

24. STPHMMC27
PART 2
SEDATION IN OMFS
Outpatient Anesthesia

25. SEDATION
STPHMMC28
 Is the reduction of irritability or agitation by
administration of sedative drugs to facilitate medical
procedures
 Sedation methods in omfs includes;
-Inhalation (using nitrous oxide)
-Oral sedation
-Intravenous

26. STPHMMC29

27. GOALS OF SEDATION
STPHMMC30
1. Optimal environment for completion of the
procedure
2. Minimize patient anxiety and optimize comfort
3. Control the patient’s behavior and movement and
optimize patient cooperation
4. Optimize analgesia
5. Maximize the potential for amnesia, and
6. Optimize patient safety, while maintaining
respiratory and hemodynamic stability

28. Indications for sedation strategies
STPHMMC31
CLINICAL
SITUATION
INDICATION PROCEDURAL
REQUIREMENTS
SUGGESTED
SEDATION
STRATEGIES
Noninvasive procedures CT
Echocardiography
Electroencephalography
MRI
Ultrasonography
Motion control
Anxiolysis
Comforting alone
Chloral hydrate PO (in
patients < 3 yr old)
Methohexital PR
Pentobarbital PO, IM, or IV
Midazolam IV
Propofol or etomidate IV
Procedure associated with
low pain and high anxiety
Dental procedures
Flexible fiberoptic laryngoscopy
Foreign body removal, simple
Intravenous cannulation
Laceration repair, simple
Sedation
Anxiolysis
Motion control
Comforting and topical or
local anesthesia
Midazolam PO/IN/PR/IV
Nitrous oxide
Procedures associated
with a high level of pain,
high anxiety, or both
Abscess incision and drainage
Bone marrow aspiration and
biopsy
Burn débridement
Foreign body removal,
complicated
Fracture or dislocation
reduction
Laceration repair, complex
Sedation
Anxiolysis
Analgesia
Amnesia
Motion control
Propofol or etomidate IV
Propofol and fentanyl IV
Propofol and ketamine IV
Ketamine IM/IV
Midazolam and fentanyl IV

29. Inhalational Sedation
STPHMMC32
 Properties of an ideal anesthetic gas
 Be predictable in onset and emergence
 Provide muscle relaxation, cardiostability and
bronchodilation;
 Not trigger malignant hyperthermia or other significant
side effects (such as nausea and vomiting);
 Be inflammable
 Undergo no transformation within the body; and allow
easy estimation of concentration at the site of action.

30. Inhalational Sedation
STPHMMC33
 Indications
1. Uncooperative children of reasoning age.
2. Mildly apprehensive adult patients.
3. Medically compromised patients.
4. Patients with gagging problem.

31. Inhalational Sedation
STPHMMC34
 Contraindications
1. Patients with extreme anxiety.
2. Nasal obstruction, sinus problem, common
cold, habitual mouth breathing.
3. Upper respiratory tract infections.
4. Patients with serious psychiatric disorders.
5. Chronic obstructive pulmonary disease
(COPD).
6. First trimester of pregnancy

32. Inhalational Sedation
STPHMMC35
 INHALATION ANESTHETICS
- Nitrous oxide (N2O)
- Isoflurane
- Sevoflurane
- Desflurane
 The halogenated agents are extremely potent and are
used for induction and maintenance of general
anesthesia

33. Intravenous Sedation
STPHMMC36
 Advantages of Intravenous Sedation
1. Highly effective technique
2. Rapid onset of action
3. Titration is possible
4. Patent vein is a safety factor
5.Nausea and vomiting less common
6. Gag reflex diminished
7. Motor disturbances (epilepsy, cerebral palsy)
diminished

34. Intravenous Sedation
STPHMMC37
 Disadvantages of Intravenous Sedation
1. Vein puncture is necessary.
2. Vein puncture complications.
3. More intensive monitoring required.
4. Delayed recovery.

35. Intravenous Sedation
STPHMMC38
 Drugs Commonly Available for IV Sedation
1. Sedative, hypnotics and antianxiety drugs
a.Barbiturates—older sedative-hypnotics, general
depression of
CNS e.g. methohexitone
b.Benzodiazepines—wildly used, not to lead general
anesthesia
e.g. diazepam, midazolam
2. Nonbarbiturate hypnotics
a. Propofol
b. Ketamine
c. Innovar (droperidol and fentanyl combination)
3. Antihistaminics—promethazine
4. Narcotic agonists— pethidine, pentazocine, fentanyl

36. SEDATION
STPHMMC40
 Clinical Indicators of Over sedation
1. Patient uncomfortable.
2. Persistent closing of mouth.
3. Spontaneous mouth breathing.
4. Patient responds sluggishly to command.
5. Patient becomes uncooperative.
6. Patient laughs, cries, or feels giddy.
7. Patient has uncoordinated movements.
8. Patient talks incoherently

37. Complications After Sedation
STPHMMC41
COMPLICATION ETIOLOGY
Delayed awakening Prolonged drug action
Hypoxemia, hypercapnia,
hypovolemia
Agitation Pain, hypoxemia, hypercapnia,
full bladder
Paradoxical reactions
Emergence reactions
Nausea and vomiting Sedative agents
Premature oral fluids
Cardiorespiratory events
Tachycardia
Bradycardia
Hypoxia
Pain, hypovolemia, impaired
ventilation
Vagal stimulation, opioids,
hypoxia
Laryngospasm, airway
obstruction, oversedation

38. DISCHARGE CRITERIA
STPHMMC42

39. STPHMMC43
GENERAL ANESTHESIA
IN OMFS

40. General Anesthesia
STPHMMC44
 is a controlled state of unconsciousness,
accompanied by partial or complete loss of protective
reflexes, including the inability to independently
maintain an airway or respond purposefully to verbal
command

41. Stages of anesthesia
STPHMMC45

42. INDUCTION
STPHMMC46
 The time from administration to development of
effective surgical anesthesia
 Can be induced by Iv or inhalation agents
 Halothane remains a popular agent, because of
smooth, rapid induction

43. Maintenance Of Anesthesia
STPHMMC47
 Is the period during which the patient is surgically
anesthesized.
 Usually maintained by the inhalational agents
 Opioids such as fentanyl, are often used for pain
along with inhalation agents

44. RECOVERY
STPHMMC48
 The time from discontinuation of administration
until consciousness & protective physiologic
reflexes are regained.
 Postoperatively, the anesthesiologist withdraws
the anesthetic mixture and monitors the return of
the patient to consciousness.

45. DEPTH OF ANESTHESIA
STPHMMC49
THE FOUR STAGES OF
ANESTHESIA
1. Stage I- Analgesia
2. Stage II- Excitement
3. Stage III- Surgical anesthesia
4. Stage IV- Medullary paralysis

46. TYPES OF GENERAL
ANESTHESIA
STPHMMC50
GENERAL
ANESTHESIA
INHALATION
ANESTHETICS
INTRAVENOUS
ANESTHETICS

47. Balanced Anesthesia
STPHMMC51
Multidrug approach & takes advantage of each drug’s
Minimize patients risk & maximize patient comfort
and safety
Anesthetized with an IV agent
Inhalational agents for maintenance of anesthesia

48. Balanced Anesthesia
STPHMMC52
 Supplemental analgesic
 Neuromuscular blocking agents( succinylcholine or the
curariform)
 Reversal agents(Naloxone, Nalmefene,
Flumazenil)
 Anti-emetic Medications

49. STPHMMC54
Mechanisms of Anesthesia

50. STPHMMC55
PART 3
SPECIFIC ANESTHETIC
AGENTS

51. INHALATIONAL AGENTS
STPHMMC56
Nitrous oxide
 Has anxiolytic, analgesic, amnestic, and sedative
effects.
 Possesses a wide margin of safety and few residual
side effects.
 Has low solubility -rapid equilibration between the
alveoli and the blood and the blood and the brain.
 This results in both rapid onset and anesthetic
emergence.

52. INHALATIONAL AGENTS
STPHMMC58
Nitrous oxide
 Techniques of Administration
• It always begin and end with the patient receiving 100
percent oxygen.
• Avoid a heavy meal prior to the sedation.
• During sedation keep verbal communication with the
patient and monitor vital signs and SPO2.
• Position the patient in comfortable, reclining position
in dental chair.
• Start the flow of oxygen at 5.0 liters per minute
• place the nasal-mask over the patient’s nose.
• Remind the patient to breathe through the nose

53. INHALATIONAL AGENTS
STPHMMC59
Nitrous oxide
 Initially nitrous oxide is given in the concentration
of 10 % for a few breaths,
 Then increased slowly till patient experiences
some sensory disturbance, such as tingling
sensation in fingers, toes, lips or tongue and
tinnitus.
 At this point the concentration of nitrous oxide is
decreased slightly as this is probably just beyond
the desirable point and proceed with local
anesthetic injection.

54. INHALATIONAL AGENTS
STPHMMC61
Halothane
 Halothane remains a popular agent, because of
smooth, rapid induction & recovery
 It has a nonirritant relatively pleasant smell.
 Weak analgesic
 However, there is 30 percent incidence of
dysrhythmias during halothane anesthesia.
 A concentration of 3 to 4 % for induction & 1 to 2 %
for maintenance of anesthesia

55. INHALATIONAL AGENTS
STPHMMC62
 Halothane administration can result in:
Reduction in BP,COP,
Myocardial depression
Depresses respiratory function
Not opposed by reflex sympathetic activation
Hepatotoxic
Malignant hyperthermia
Should be taken into account for patients with cardiac
disease

56. INHALATIONAL AGENTS
STPHMMC63
Isoflurane
Pungent smell and is irritant to the
tracheobronchial tree
Safe anesthetic in patients with ischemic heart disease
Myocardium does not appear to be sensitized to the
effects of catecholamines
Fluoride production is quite low
Preserves cardiovascular stability
Most popular

57. INHALATIONAL AGENTS
STPHMMC64
Methoxyflurane
Most potent inhalational agent available
High solubility in tissues limits its use as an induction
anesthetic
Does not depress cardiovascular reflexes
Arterial blood pressure is better maintained
Causing renal tubular dysfunction.

58. INHALATIONAL AGENTS
STPHMMC65
Enflurane
Depresses myocardial contractility and lowers
systemic vascular resistance
Does not block sympathetic reflexes
Results in tachycardia
Cardiac output and blood pressure fall
Sensitizes the myocardium to catecholamine
Depresses respiration

59. INHALATIONAL AGENTS
STPHMMC66
Desflurane
Low tissue and blood solubility
Partial pressure is thus established more
rapidly.
Popularity for outpatient procedures
Irritates the respiratory tract
Marked reductions in PCO2

60. INHALATIONAL AGENTS
STPHMMC67
Sevoflurane
Has low tissue and blood solubility
Rapid induction and emergence
Useful for outpatient and ambulatory
procedures.
Particularly useful in pediatric anesthesia

61. STPHMMC68

62. Intravenous Agents
STPHMMC70
Ketamine
 Is 10 times more lipid soluble than thiopental,
 It to cross the blood-brain barrier (BBB) quickly.
 It produces dissociative anesthesia
 Stimulates the CVS, increasing the HR, BP, and
COP
 Recommended for hypovolemic patients
 Potent cerebral vasodilator and will increase ICP
 Unpleasant auditory, visual, and out-of body illusions
that can progress to delirium

63. Intravenous Agents
STPHMMC71
Ketamine

64. Intravenous Agents
STPHMMC72
Etomidate
 Is used primarily as an induction agent for GA at 0.2
to 0.4 mg/kg
 Induction agent recommended for use in major
trauma or other hypovolemic states because of its
cardiac stability
 Its main advantage over barbiturates and propofol is
cardiovascular stability.
 BP decrease by up to 15% but changes in HR are
minimal.
 Usually reserved for patients with unstable cardiac
disease

65. Intravenous Agents
STPHMMC73
Propofol:
 Most recent IV anesthetic agent
 Is the best agent for outpatient anesthesia bcs of
• Rapid induction and recovery
• Lower incidence of nausea and vomiting
 Used as a sedative , an induction and maintenance agent
for GA
 Should be avoided in patients with soy and egg allergies
as well as lipid disorders
 Sedative dose of propofol is 10 to 50 mg/kg/minute.
Adverse Effects.
 Transient apnea and respiratory depression can occur but typically
resolve spontaneously

66. Intravenous Agents
STPHMMC74
Propofol and ketamine combination:
 Addition of small dose of ketamine (10–30
micrograms/kg/hr) to propofol (0.5–1.5 mg/kg/hr)
 Might provide the ideal sedative combination in
dentistry, producing titratable sedation, intense
analgesia, increased hemodynamic stability,
 less respiratory depression and a low incidence of
psychomimetic side effects

67. Intravenous Agents
STPHMMC75
Barbiturates
 They exhibit a dose-dependent CNS depression with
hypnosis and amnesia.
 Produce sedation, loss of consciousness, and
amnesia.
 Do not provide analgesia
 Very lipid soluble, results in a rapid onset of action..
 Thiopental, Methohexital , Pentobarbital
 Thiopental sodium (Pentothal ) is most commonly used
barbiturates for induction of anesthesia

68. Intravenous Agents
STPHMMC76
Thiopental :
 Commonly used at 3 to 5 mg/kg intravenously in a
2.5% solution
 Induce loss of consciousness for GA before ET
intubation
 Can release histamine, which is a concern in
asthmatic patients.
 The long elimination half-life of thiopentone (9 hours)
makes it unsuitable for outpatient anesthesia

69. Intravenous Agents
STPHMMC77
Methohexital
 Is an ultrashort-acting
 Common for outpatient oral surgical procedures
 More rapid recovery compared with thiopental & its
lower cost compared with propofol.
 1.5 to 2 mg/kg intravenously for induction of general
anesthesia.
 Associated with involuntary movements such as
myoclonus and hiccuping.
 Shivering upon awakening is also common

70. Intravenous Agents
STPHMMC78
Pentobarbital
 Short-acting barbiturate
 Duration of action - 2 to 4 hours.
 Used for conscious sedation in doses of 100 to 300
mg,
 Combined with opioids & benzodiazepines for longer
operative procedures.
 CVS effects are more modest than with the
ultrashort-acting agents.

71. Intravenous Agents
STPHMMC79
Benzodiazepines
 Midazolam (most common),Lorazepam,Diazepam
 Clinical uses for benzodiazepines
• Preoperative medication
• Intravenous sedation
• Induction of anesthesia
• Maintenance of anesthesia
• Suppression of seizure activity
 Anterograde amnesia, minimal depression of ventilation
and the cardiovascular system, and sedative properties
make benzodiazepines favorable preoperative medications

72. Intravenous Agents
STPHMMC80
Midazolam
 Possess anxiolytic, amnestic, sedative, hypnotic,
muscle relaxant, and anticonvulsant properties.
 lack direct analgesic properties and thus are
commonly coadministered with opioids
 Is preferred over the longer-acting lorazepam and
diazepam.
 Peak effect approximately 2 to 3 minutes when given
iv
 Water soluble, thus making parenteral administration
less painful and mucosal absorption faster.
 Readily reversed with flumazenil

73. Intravenous Agents
STPHMMC81
Midazolam
 Adult Use. used effectively for moderate and deep
sedation
 Pediatric Use. Advantages of midazolam over other
benzodiazepines for pediatric are its short duration
of action, reversibility, and availability in multiple
routes of administration.
 Is ideal for painful procedures , bcs of its significant
amnesic effect

74. Intravenous Agents
STPHMMC82
Diazepam
 used for IV moderate sedation,
 Given in 2.5- to 5-mg increments every few
minutes.
 IV injection can be painful, Onset of sedation
occurs in several minutes
 longer elimination time than Midazolam
 Can also be given orally (5–10 mg) for
preoperative anxiolysis and minimal sedation

75. STPHMMC83

76. Analgesic Agents
STPHMMC84

77. Neuromuscular Blocking
Agents
STPHMMC85
Skeletal muscle relaxation is often required during
surgery when patient movement interferes with
procedures involving anesthesia or surgery.
Paralysis may be required to facilitate tracheal
intubation
Muscle relaxation does not ensure
unconsciousness, amnesia, or analgesia
Neuromuscular blocking agents are divided into
two classes:
• Depolarizing
• Nondepolarizing

78. Common Neuromuscular Blocking
Medications and Their Properties
STPHMMC86
Intubating Dose
(mg/kg)
Time to
Intubate (min)
25% Twitch
Recovery (min)
Metabolism and
Elimination
Vagolysis
Depolarizing
Succinylcholine 1 1 5-10 Plasma
cholinesteras
e
0
Nondepolarizing
Aminosteroids
Rocuronium
Vecuronium
Pancuronium
Pipecuronium
0.6-1.2
0.1-0.12
0.08-0.1
0.07-0.085
1-1.5
2-3
3-5
3-5
40-50
25-30
80-100
50-120
Liver; kidney
Liver; kidney
Liver; kidney
Liver; kidney
0
0
+
+-
Benzylisoquinolin
es
Atracurium
Cisatracurium
Doxacurium
D-Tubocurarine
0.4-0.5
0.15-0.2
0.05-0.08
0.5-0.6
2-3
1.5-2
4-5
3-5
25-30
50-60
100-160
80-100
Hofmann
elimination
Liver; kidney
Liver; kidney
0
0
0
0

79. STPHMMC87

80. ANTIEMETIC MEDICATIONS
STPHMMC88
 PONV is one of the most common complaints after
surgery.
 Certain groups of patients more susceptible
 - Female -Obese - Previous history of nausea
and vomiting
 Certain surgeries (ear, ocular, tonsillar, gynecologic)
are likewise associated with increased PONV.
 Nausea and vomiting after oral surgery are not
uncommon.
 Drugs used during sedation and anesthesia, may
trigger nausea postoperatively.
 Other “nonchemical” triggers of nausea include smell,
gastric distention, motion, and even stress

81. ANTIEMETIC MEDICATIONS
STPHMMC89
 Dopamine receptor blockers; phenothiazines &
butyrophenones
 Antihistamines ; promethazine & diphenhydramine
 Anticholinergics ; hydroxyzine & benadryl
 Dexamethasone ; decrease the incidence of PONV
when given shortly after induction of GA.
 Selection of anesthetic agents may help prevent
PONV.

82. Reversal Agents
STPHMMC90
 Naloxone ; reverse opioids
 Physostigmine ; reverse sedative effects of
• Benzodizepams
• Droperidol
• Scopolamine
• Opioids
• Phentothiazen
 Flumazenil ;reverse all effects of
benezodiazepams only
 Edrophonium,Neostigmine,Pyridostigmine;revers
e neuromuscular agents

83. STPHMMC91
Part 4
Complications Of GA
References

84. Complications of General
Anesthesia
STPHMMC92

85. Complications of General
Anesthesia
STPHMMC93
Hypothermia
Causes
 Heat loss due to
– radiation
– conduction
– convection
– evaporation from body
Management: Warm the patient

86. Complications of General
Anesthesia
STPHMMC94
Malignant Hyperthermia
 is a very rare complication of general anesthesia
with a high mortality, unless it is detected and
treated early.
Symptoms;
 high fever, tachycardia, tachypnea, cyanosis.
Cause:
 Triggering agent—inhalation anesthetic agents or
suxamethonium.

87. Complications of General
Anesthesia
STPHMMC95
Malignant Hyperthermia
Management
1. Stop anesthesia and disconnect patient from the
anesthesia machine
2. Ventilate with 100 percent oxygen.
3. Start cooling the patient (ice packs).
4. Treat arrhythmias.
5. Treat acidosis and hyperkalemia.
6. Maintain urine output with IV fluids.
7. Give dantrolene if available. It is a specific
treatment which lowers mortality.

88. References
STPHMMC96
Lippincot ,Modern pharmacology with
clinical application ,5th eddition
goodman & gilman's the pharmacological
basis of therapeutics - 11th ed. (

89. STPHMMC97