Transcript Conscious Sedation

PRESENTED BYSUVIDHA SETH
III YEAR
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HISTORY
INTRODUCTION
DEFINITIONS
AIMS & OBJECTIVES OF CONSCIOUS SEDATION
PREREQUISITIES FOR SEDATION
ANATOMIC & PHYSIOLOGICAL
DIFFERENCES(CHILD/ADULTS)
INDICATIONS & CONTRAINDICATIONS
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PATIENT ASSESSMENT & PREPARATION
LEVELS OF SEDATION & GA
DRUGS USED FOR CONSCIOUS SEDATION
AAP / AAPD GUIDELINES
CONCLUSION
REFERENCES
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To perform the highest quality dental care in
pediatric patients, the practitioner may need to
use pharmacologic means to obtain a quiet,
cooperative patient.
Techniques that use drugs to induce a
cooperative yet conscious state in an otherwise
uncooperative child are most commonly
referred to as techniques of conscious sedation.
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Before the middle of 19th century many
agents like alcohol were used to obtund
surgical pain, but operations were horrible
ordeals.
Dr. Horace Wells (Dentist &
Discoverer of Anesthesia), used
NITROUS OXIDE (N2O) from
a demonstration of laughing
gas(1844). However he often
failed to relieve dental pain
completely & its use had to wait.
Dr. W. Morton (1846),dentist at
Boston , successfully used ETHER
for extraction of a tooth & it became
very popular.
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CHLOROFORM was used by Simpson,(1847), for
Obstetrical purposes & despite its toxic potential,
became a very popular surgical anesthetic.
Nitrous oxide was not used until 1863,when
Colton reintroduced the gas into dentistry.
In 1868,Andrews,an American physician ,
introduced the combined use of nitrous oxide &
oxygen inhalation.
CONSCIOUS SEDATIONA minimally depressed level of
consciousness, that retains the patient’s
ability to maintain an airway independently &
respond appropriately to physical stimulation
& verbal commands.
(AMERICAN DENTAL ASSOCIATION,1993)
CONSCIOUS SEDATION (Old Terminology)Now called as MODERATE SEDATION
Moderate Sedation-Analgesia: A
drug-induced
depression of consciousness during which patients
respond purposefully to verbal commands, either alone
or accompanied by light tactile stimulation.
This includes—
 Airway is patent, & spontaneous ventilation is adequate.
 Cardiovascular function is usually maintained.
 Reflex withdrawal from a painful stimulus is not
considered a purposeful response.
(AAP/AAPD GUIDELINES,2006)
ANXIOLYSIS (old terminology)
Now called as MINIMAL SEDATION
A drug-induced state during which patients
respond normally to verbal commands.
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Cognitive function & coordination may be
impaired.
Ventilatory and cardiovascular functions are
unaffected.
(AAP/AAPD Guidelines 2006)
DEEP SEDATIONA drug induced depression of
consciousness during which patients cannot
be easily aroused but respond purposefully
after repeated verbal or painful stimulation.
(AAP/AAPD Guidelines 2006)
The ability to independently maintain ventilatory
function, may be impaired.
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Patients may require assistance in maintaining a
patent airway.
 Cardiovascular function is usually maintained.
 A state of deep sedation may be accompanied by
partial or complete loss of protective airway
reflexes.
GENERAL ANESTHESIAA controlled state of unconsciousness,
accompanied by partial or complete loss of
protective reflexes, including inability to
maintain an airway independently & respond
purposefully to physical stimulation or verbal
command.
(AMERICAN DENTAL ASSOCIATION,1993)
Guard the patient’s safety and welfare
2. Minimize physical discomfort and pain
3. Control anxiety, minimize psychological trauma
4. Maximize the potential for amnesia
5. Control behavior and movement to allow the
safe completion of the procedure
6. Return the patient to a state in which safe
discharge from medical supervision, as
determined by recognized criteria.(AAP 2006)
These goals can best be achieved by selecting the
lowest dose of drug with the highest therapeutic
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The practitioner should have knowledge of
the agents to be used & should be trained
for their administration.
There should be a well-documented
informed consent by parent/guardian who
has had a consultation on the alternatives &
risks.
There should be no lack of equipment to
complicate the management of an
emergency.
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There should be carefully planned rationale
for use of sedation which is based onbehavior of patient,
nature & extent of treatment required,
risk-to-benefit ratio,
capability of family to meet the demands of an
extensive treatment plan &
◦ the economic feasibility.
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Mobile emergency medical services should be
readily available.
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Difference in BASAL METABOLIC RATE.
Greater in children, which ultimately affects
not only the drug response, but also
important physiologic parameters.
Difference in RESPIRATORY RATE. Because
oxygen demand is greater, but the alveolar
system is less mature, the respiratory rate is
far higher in children than adults. So, it must
be considered when giving drugs that
depress the respiratory system.
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AIRWAY MANAGEMENT is different because
of anatomic variations. The narrow nasal
passages, glottis, hypertrophic tonsils &
enlarged tongue produce a much greater
risk of airway obstruction.
The airway of all patients should be examined
prior to sedation. Patients with tonsillar tissue
that occupies more than 50% of pharyngeal
space are at an increased risk of respiratory
obstruction.
Classification of tonsil size should be completed for all
patients prior to sedation. Patients classified as +3 or
greater (having more than 50% of the pharyngeal area
occupied by tonsils) are at increased risk of developing
airway obstruction.
Cote CJ et al. A practice of anesthesia for infants and
children, Philadelphia, 1993, WB Saunders, pp 313-314.
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Children demonstrate a reduced tolerance to
respiratory obstruction.
Thus, sudden APNOEA is a great concern in
pediatric age group. Because thorax is
smaller, with less expansion capability &
children have less functional reserve. So, are
prone to rapid obstruction or respiratory
depression.
For this reason children with sleep apnea are
not good candidates for conscious sedation.
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CARDIOVASCULAR parameters are different
for children. The heart rate is faster and
blood pressure is lower than in the adult.
Children are more susceptible to
bradycardia, decreased cardiac output, and
hypotension.
Compensatory mechanisms to maintain
adequate blood pressure when the heart rate
is depressed are not so developed.
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Thus a decrease in heart rate leads to a
corresponding decrease in blood pressure
and tissue oxygenation.
So, it must be taken into consideration about
those drugs that depress the heart rate in
pediatric patients.
AGE (YEAR)
HEART RATE
(BEATS /
MINUTE)
BLOOD
PRESSURE
MM / HG
RESPIRATORY
RATE
(BREATHS /
MINUTE)
1-3
70-110
90-105 / 55-70
20-30
3-6
65-110
95-110 / 60-75
20-25
6-12
60-95
100-120 / 60-75
14-22
12
55-85
110-135 / 65-85
12-18
Behrman, et al: Nelson textbook of Pediatrics, ed 17
These differences between children at different
age levels and adults leads to the conclusion
that dosage is not simply an application of a
formula for derivation of a percentage of the
adult dose of any agent.
Drug dosages for children should be
carefully individualized for each patient
following established guidelines.
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Patients who cannot cooperate &
understand for definitive treatment.
Patient lacking cooperation because of
lack of psychological or emotional
maturity
Patients with dental care requirements,
but are fearful & anxious.
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Chronic obstructive pulmonary disease
(COPD), epilepsy, & bleeding disorders.
Uncooperative or unwilling patients.
Unaccompanied patients..
Prolonged surgery.
Lack of equipment or inadequate personnel.
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Obtaining patient history & information.
Informed consent from the accompanying
parent/ guardian.
Instructions to parents preop & postop.
Adequate documentation of the sedation
experience with monitoring of vital signs.
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b)
OBTAINING PATIENT HISTORY AND
INFORMATIONInformation exchanged through a formal
interview helps in assessment of patient pain
& anxiety.
M/H specific to Sedationa)
b)
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Abnormalities of major organ systems.
Previous adverse experience with sedation / GA.
Drug allergies & current medications.
Age in years & months & weight in kgs.
Time & nature of last oral intake.
American Society of
Anesthesiologists: Manual for
Anesthesia department
Organization & Management, Park
Ridge, 2003
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ASA Physical Status Classification SystemASA I- Patients with no systemic disease.
These patients are able to tolerate mild
physical exertion & psychologic stresses.
They do not possess any organic,
physiologic, biochemical, or psychiatric
disturbances.
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ASA II- Patients with mild-to-moderate
physiologic disturbance that is under good
control. No significant compromise of
normal activity, but patient’s specific
condition could possibly affect safety of
surgery & anesthesia.
ASA III- Patients with a major systemic
disturbance that is difficult to control, there
is significant compromise of normal activity
for this patient. This situation creates a
significant impact on surgery & anesthesia.
Medical consultation recommended for these
patients.
4. ASA IV- Patients with severe & potentially
life threatening systemic disease that
significantly limits their activity are not
usually seen in ambulatory health setting.
Because of their unstable health problems,
they are categorized as high risk for many
situations & potential for acute emergency
situation is great. Seek medical consultation
and/or referral.
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ASA V- Moribund patient in whom
immediate surgery is the last effort to save
their lives.
ASA VI- The patient in this classification is
clinically dead (i.e. declared brain-dead
patient), but being maintained for organ
donation.
ASA E- Designation for a patient requiring
an emergency procedure.
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Only patients who are categorized into ASA
class I are routinely acceptable as candidates
for conscious sedation.
Children assigned to ASA classes II & III may
actually benefit from this approach, but this
must be determined in consultation with the
child’s physician.
Generally, patients categorized into classes III
& IV are better managed in a hospital setting.
INFORMED CONSENT- Parent/
Guardian must be agreeable to the
use of conscious sedation for the
child.
They should receive complete
information regarding--
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Risks &
Benefits associated with the particular
technique.
Agents being used.
Alternative methods , if available.
3. INSTRUCTIONS TO PARENTS This information should include a 24-hour
contact number for the practitioner.
 Dietary instructions are as follows:
1. No milk or solids for 6 hours for children 6 to 36
months old and for 6-8 hours for children 36
months and older.
2. Clear liquids upto 3 hours before the procedure
for children aged 6 months and older.
Reasons for the instructions to parents1. Emesis during / after a sedative procedure is
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a potential complication that can result in
aspiration of stomach contents leading to
laryngospasm or severe airway obstruction.
Aspiration may even lead to aspiration
pneumonia.
If the drug is taken by oral route, its uptake
is maximized when the stomach is empty.
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On arriving home, the child may sleep for
several hours, may be drowsy & irritable for
upto 24 hours. Should be monitored while
sleeping, to ensure an open airway.
After treatment child should first be offered
clear liquids & then solid foods as tolerated.
Once solids are tolerated, there are no
dietary restrictions.
4. ADEQUQTE DOCUMENTATION OF SEDATION
EXPERIENCE Intraoperatively vital signs should be
recorded.
 Type of drug, dose given, route, site, and
time of administration should be noted.
 After completion of treatment, the patient be
observed in a well-equipped recovery area.
The patient should remain under direct
observation until respiratory and
cardiovascular stability have been ensured.
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GASES
ANTIHISTAMINES
BENZODIAZEPINES & ITS ANTAGONIST
SEDATIVE HYPNOTICS
NARCOTICS & ITS ANTAGONIST
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Gases used most commonly in Conscious
Sedation techniques– Nitrous Oxide (N2O) &
Oxygen(O2).
85% of Pediatric dentists use Nitrous oxide &
oxygen for sedation of patients. This makes it
the most frequently used sedative agent.
Physical / Chemical properties of N2O:
 Nitrous oxide (MW 44 & Sp gravity 1.53) is a slightly
sweet-smelling, colourless, inert gas.
 Boiling point is 88.5°C (127°F), indicates it is gas at room
temperature.
 When compressed in cylinder it becomes liquid & vaporizes
on release.
 It is nonflammable but, supports combustion.
Physical / Chemical Properties of O2:
 O2 (MW 32 & Sp gravity 1.1) is a odorless, colorless &
tasteless gas.
 It also supports combustion, but is nonflammable.
DESIRABLE CHARACTERSTICS OF N2O/O2
SEDATION:
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Analgesic Properties (Pain Control)20% N2O & 80% O2 has the same effect
as 15mg of Morphine. Has the ability to
manage both pain & fear (fear of an
injection).
Amnestic properties- Postoperatively
patients are unable to recall the severity
of their pain or anxiety or its duration.
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Anxiolytic properties (sedative effects)Assist patients in handling their fear of
anxiety by producing sedation or a sense
of well-being. Facilitates positive behavior.
Onset of Action- Rapid less than 30
seconds, peak effects in less than 5 minutes.
Recovery- Inhalation of N2O/O2 allows for
complete recovery with 100% pure oxygen
for 5 minutes after termination of drug.
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Elimination- It is 99% eliminated from the
body within 5-10 minutes after
discontinuation of use.
Acceptance- Patient acceptance rate is same
for oral surgical procedures as it is for
general dentistry.
COMBINING N2O/O2 SEDATION WITH OTHER
METHODS:
1. Combination with Audio-analgesia. Since
music is a method for relaxing, distracting
(also known as “white sound”).
2. Oral premedication with Diazepam &
Meperidine.
3. N2O/O2 & Local anesthesia because together
offer superior pain & anxiety management
option.
PHARMACOKINETICS OF N2O:
 It has a blood-gas partition coefficient of
0.47 i.e. difference between partial pressures
of gas (N2O) & liquid (blood) indicates how
quickly agent crosses the pulmonary
membrane & enters the blood stream.
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It is an insoluble drug & remains unchanged
in blood & does not combine with any blood
elements.
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Since N2O does not break down, so peak
clinical effects may be seen within 3-5
minutes.
There is no biotransformation & 99% of gas
is rapidly eliminated by the lungs. Very small
amounts may be found excreted in body
fluids and intestinal gas.
PHARMACODYNAMICS OF N2O:
 It produces nonspecific CNS depression.
Although classed with inhalational GAs, it
produces limited analgesia, & thus surgical
anesthesia is unlikely unless concentrations
producing anoxia are reached.
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So, O2 is given along with it, because its sole
purpose is to avoid anoxia.
To minimize the effect, the patient should be
oxygenated for 3-5 minutes after a sedation
procedure.
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At concentrations 30-50%, N2O will produce a
relaxed & dissociated patient who is easily
susceptible to suggestion. Amnesia, but there is
little alteration of learning or memory.
Moderate sedation is achieved when N2O
concentration is 50% .
At concentrations greater than 60%, patients may
experience discoordination, ataxia, giddiness, and
increased sleepiness.
Concentrations greater than 50% are not to be
used in dental practice.
The gas is nonirritating to the respiratory tract and
can be given to patients with asthma without fear
of bronchospasm.
ADVERSE EFFECTS AND TOXICITY
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Nausea and vomiting are the most common adverse effect
experienced with N2O sedation. Increases with more than
50% conc or lengthy procedures.
Middle ear pressure can increase pain in patients with acute
otitis media. It gets entrapped in gas-filled spaces such as
the middle ear, sinuses, and GIT.
Neurotoxicity, impotence, and renal/liver toxicity.
The greatest concern regarding toxicity centres on exposure
of dental personnel to high ambient air levels of the gas
during its use for patient sedation (i.e. longer than 3 hours
per week
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Second gas effect : When N2O is being given
at 70-80% concentration initially, though it
has low solubility in blood, about 1l/min of
N2O enters blood in first few minutes higher
than minute volume.
So, if another anesthetic is given at same time
,it will be delivered to the blood at same rate
i.e. 1l/min which is higher than minute
volume & induction effect will be faster,
called as SECOND GAS EFFECT.
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DIFFUSION HYPOXIA- Reverse occurs when
N2O is discontinued after prolonged
anesthesia. Since N2O has low blood
solubility it rapidly diffuses into alveoli &
dilutes O2 in alveoli (due to PP of O2 in
alveoli is reduced), thus O2- CO2 exchange is
disrupted & a period of hypoxia is created.
This can be prevented by continuing 100%
O2 for 5 minutes at termination of procedure.
Diffusion hypoxia is not significant with other
anesthetic agents because they are given at
low conc (0.2-0.4) & are not able to dilute
alveolar air.
EQUIPMENT:
 The machine should be of the continuousflow design, with flowmeters capable of
accurate regulation.
 A fail-safe mechanism that provides
automatic shutdown if O2 falls below 25% and
audible and visual alarms that are activated.
 There should be a flush lever for easy and
immediate flushing of the system with 100%
oxygen.
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Efficient “SCAVENGER SYSTEM” is an
important component of any hose-mask
system. The double mask type is the most
efficient type of scavenger. These systems
exhaust into the vacuum waste system, which
is vented to the outside.
Nasal hoods should be of good design & be
available in pediatric & adult sizes both.
Schematic diagram to
show components of a
N2O/O2 delivery &
scavenging system
TECHNIQUE- After a
thorough inspection
of the equipment, the
mask should be
introduced to the
patient with an
explanation, and then
the mask should be
carefully placed over
A-Poorly fitting mask with leakage under
the nose.
nares.
B-Well -fitting mask.
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The delivery tubes are tightened behind the
chair back in a comfortable position.
Bag is filled with 100% oxygen and delivered
to the patient for 2/3 minutes at an
appropriate flow rate of 5-6 L /minute.
With an appropriate flow rate, slight
movement of the mixing bag should be
apparent with each inhalation and exhalation.
Too high flow rate, the bag will be
overinflated, movement will not be seen with
each breath.
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Too low flow rate will deplete the bag of
mixed gases.
Once the proper flow rate is achieved, the
N2O can be introduced by slowly increasing
the concentration at increments of 10% to
20% to achieve the desired level.
The operator should encourage the patient to
breathe through the nose with the mouth
closed.
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SENSATIONS- Felt are floating, giddy feeling
with tingling of digits. The eyes will take on a
distant gaze with sagging eyelids.
When this state is reached, the local
anesthetic may be given. Once this is
completed, the concentration can be reduced
to 30% nitrous oxide and 70% oxygen or
lower. The patient can now be maintained
and monitored & procedure carried out.
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The dentist should communicate with the
patient throughout the procedure, paying
particular attention to the maintenance of an
open, relaxed airway.
An emesis basin should be readily available,
and if vomiting does occur, the head should
be rotated to the side.
However, the laryngeal reflex is not obtunded
with nitrous oxide, and so aspiration of
vomitus is unlikely.
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Recovery can be achieved quickly by reverse
titration. Once the sedation is reversed, the
patient should be allowed to breathe 100%
oxygen for 3-5 minutes.
The patient should be allowed to sit. Even
though psychomotor effects return to normal
within 5 to 15 minutes, it is not advisable to
allow teenage patients to drive themselves.
Guidelines on Appropriate Use of Nitrous
Oxide for Pediatric Dental Patients:
1. Must be given by licensed individuals only.
2. Informed consent of parents & documented
in patients record before administration.
3. Preoperative & postoperative vital sign
values are to be recorded.
4. Select the nasal hood according to the size
of individual & make sure it fits snugly. This
can decrease patient anxiety & increase
trust.
5. Determine flow rate of each person, 5-6
L/min is acceptable for most patients.
6. Titration of N2O in intervals is recommended
for children because they exhibit signs &
symptoms of sedation so it important to
remember to allow time between increments
so drug can reach its peak effect before
adding more, this will reduce oversedation.
7. During treatment visual monitoring of the
patient’s respiratory rate & level of
consciousness.
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Pulse oximeter used when high
concentrations of N2O are used.
Once the N2O flow is terminated, 100% O2
should be delivered for a minimum of 5
minutes.
10.Patient should return to pretreatment
responsiveness before he/she is dismissed.
(AAP / AAPD GUIDELINES, 2006)
The acronym “SOAPME” offers a
routine for preparing for sedation.
SUCTION
FUNCTIONING SUCTION APPARATUS
OXYGEN
ADEQUATE OXYGEN SUPPLY & FLOWMETERS TO
ALLOW ITS DELIVERY
AIRWAY
APPROPRIATE AIRWAY (ENDOTRACHEAL TUBES,
FACE MASK)
PHARMACY ALL BASIC DRUDS NEEDED TO SUPPORT LIFE
DURING AN EMERGENCY
MONITORS
FUNCTIONING PULSE OXIMETER
EQUIPMEN
T
SPECIAL EQUIPMENT OR DRUGS FOR A PARTICULAR
CASE (E.G. DEFIBRILLATOR)
( AAP/ AAPD GUIDELINES , 2006)
Conscious Sedation that is carefully
planned and carried out by a thoughtful,
well-trained health care team will allow both
caregivers and patients to have a positive
experience rather than a bad memory…
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DENTISTRY FOR THE CHILD & ADOLESCENT; 9th edition; R E
McDonald, D R Avery, J A Dean.
ESSENTIALS OF MEDICAL PHARMACOLOGY; 5th edition; KD Tripathi
PEDIATRIC DENTISTRY; INFANCY THROUGH ADOLESCENCE;5th
edition; Casamassimo, fields, Mctigue, Novak
TEXTBOOK OF PEDODONTICS; 2nd edition; Shobha Tandon
PAEDIATRIC DENTISTRY; 3rd edition; R R Welbury,.
AAP journals ,dec 1,2006,vol 118,no-6
Guideline for Monitoring and Management of Pediatric Patients
During and After Sedation for Diagnostic and Therapeutic
Procedures,AAPD,2006.
Guideline on Use of Nitrous Oxide for Pediatric Dental
Patients,2005,VOL 35,no 6
HANDBOOK OF NITROUS OXIDE & OXYGEN SEDATION; 3rd
edition; M S Clark, A L Brunick
Textbook of pedodontics; 2nd edition; Shobha Tandon