CONSCIOUS SEDATION

• DR DHANESH N
• READER AND HEAD
• DEPT OF PEADIATRIC AND PREVENTIVE DENTISTRY
• MES DENTAL COLLEGE AND HOSPITAL, PRTINHALMANNA

INTRODUCTION

• To perform the highest quality dental care for the pediatric patient, the practitioner may need to use pharmacological means to obtain a quiescent, cooperative patient.

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• Procedural sedation can offer an effective and humane way to facilitate delivery of dental care to the young, anxious child and those with extensive treatment needs.

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TERMINOLOGY

Minimal sedation ( “Anxiolysis”): A drug induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.

Moderate sedation (conscious sedation or procedural sedation) - A drug-induced depression of consciousness during which patients respond purposefully to verbal commands. For older patients, this level of sedation implies an interactive state; for younger patients, age-appropriate behaviours (e.g., crying) occur and are expected. No intervention is required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.

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AAPD. Guideline for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures - 2016

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Deep sedation - A drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully after repeated verbal or painful stimulation . The ability to independently maintain ventilator function may be impaired. Patients may require assistance in maintaining a patent airway and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained. There may be partial or complete loss of protective airway reflexes¹³.

AAPD. Guideline for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures - 2016

General anesthesia - A drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired

GOALS

1. To guard the patient’s safety and welfare
2. To minimize physical discomfort and pain
3. To control anxiety, minimize psychological trauma, and maximize the potential for amnesia
4. To modify behavior and/or movement so as to allow the safe completion of the procedure
5. To return the patient to a state in which discharge from medical/dental supervision is safe.

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AAPD. Guideline for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures - 2016

ANATOMIC AND PHYSIOLOGIC DIFFERENCES

• Sedation in children is different from the sedation of adults.
• Difference in size, age, weight, basal metabolic rate.
• Basal metabolic activity is greater in children – affects drug response and physiologic parameters.
• Respiratory rate higher in children than adults. (Important – drugs that depress the respiratory system is administered).

McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

• 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.
• While giving drugs that depress heart rate in children is that , in children, heart rate is the primary determination of BP.
• Compensatory mechanisms - not well developed in children.
• Thus a decrease in heart rate leads to a corresponding decrease in blood pressure and tissue oxygenation.
• This concept must be well appreciated when giving drugs that depress the heart rate in the pediatric age population.

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McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

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• Airway management requires different consideration in the pediatric patient because of anatomic variations.
• The narrow nasal passages and glottis, combined with hypertrophic tonsils and adenoids, enlarged tongue, and greater secretions, produce a much greater risk of airway obstruction.
• The airway of all patients should be examined prior to sedation.

McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

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• Patients with tonsillar tissue that occupies more than 50% of the pharyngeal space are at increased risk of respiratory obstruction.

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• Children demonstrate a reduced tolerance to respiratory obstruction.

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• Sudden apnea is a greater concern in the pediatric age group. Because the thorax is smaller, with less expansion capability, children have less functional reserve.

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• Children with sleep apnea are not good candidates for conscious sedation

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McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

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• MALLAMPATI CLASSIFICATION

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.

Vital signs at various ages

McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

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INDICATIONS

• Highly anxious and uncooperative child not responding to traditional behaviour management techniques.
• Child with special healthcare needs ie with physically or mentally disabled children without any significant medical issues.

Textbook of Pediatric dentistry – Damle- 5^th edition

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CONTRAINDICATIONS

• Children with severe, compromising medical conditions which require prior stabilization of medical condition.
• Cooperative children with minimal dental needs.
• Patients with predisposing medical and/ or physical conditions that would make sedation inadvisable.
• Parental objection or choice of alternative option for treatment.
• Inadequate training to provide safe care using sedation.

Textbook of Pediatric dentistry – Damle- 5^th edition

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PATIENT SELECTION AND PREPARATION

Careful and thorugh assessment of the patient is necessary to ensure correct decisions are made regarding the planning of treatment.

1. Medical history
2. Physical status
3. Informed consent
4. Instructions to parents

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1.Medical history

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• Allergies and previous allergic or adverse drug reactions.
• Current medications, including dosage, time, route, and site of administration.
• Diseases or abnormalities in the patient, including pregnancy status of adolescents.
• Previous hospitalizations, including the date, purpose, and hospital course.
• History of general anesthesia or sedation and any associated complication.
• Family history of diseases and anesthetic complications.
• Review of body systems.
• Age in years and months and weight in kilograms.

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McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011.

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2. Physical status

• Vital signs - heart and respiratory rates and blood pressure.
• Evaluation of airway patency.
• Name, address, and telephone number of the child’s medical home.
• ASA classification.

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Patient belonging to ASA I and II present minimal chance of adverse reactions during anaesthesia.

ASA III and above - preferably treated under GA.

McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011

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3. Informed consent

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• The parent or legal guardian must be agreeable to the use of sedation for the child.

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• These individuals are entitled to receive complete information regarding the reasonably foreseeable risks and the benefits associated with the particular technique and agents being used, as well as any alternative methods available.

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• Therefore the explanation should be in clear, concise terms that are familiar to them.

McDonald, Avery, Dean. Dentistry for the child and adolescent. 9^th ed. Elsevier 2011

4. Instruction to parents

Dietary instructions should be as follows (AAPD guidelines)

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1. Clear liquids : Water, fruit juices without pulp, carbonated beverages, clear tea, black coffee upto 2 hours before the procedure.
2. Breast milk upto 4 hours before the procedure.
3. Infant formula upto 6 hours before the procedure
4. Nonhuman milk upto before the procedure.
5. A light meal upto 6 hours before the procedure. A light meal typically consists of toast and clear fluids. Meals that include fried or fatty foods or meat may prolong gastric emptying times and should be avoided.
6. It is permissible for routine necessary medications to be taken with a sip water on the day of the procedure.

AAPD. Guideline for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures - 2016

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• Example of presedation instructions to the parent or caregiver

• Reasons for these recommendations-

1. Emesis during or immediately after a sedative procedure is a potential complication that can result in aspiration of stomach contents leading to laryngospasm or severe airway obstruction.

• Aspiration may even present difficulties later in the form aspiration pneumonia.

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2. Most sedative agents are administered by the oral route, drug uptake is maximised when the stomach is empty.

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Instructions before the procedure

• According to sedation guidelines given by ASA, principle of SOAPME has to be followed:
• S- Suction apparatus
• 0- Oxygen, adequate O2 supply, working flow or delivery devices.
• A- Airway age/size appropriate airway equipment
• P- Pharmacy – all basic life saving drugs including reversal agents.
• M- Monitors – Pulse oximeter, BP, ECG, stethoscope, thermometer, capnograpg.
• E- Equipment – Anesthesia machine special equipment or drugs for particular child should be readily available.

Post sedation instructions

• The child should be first offered clear fluids and may advance to solid foods as tolerated.
• Once solids are tolerated, there are no dietary restrictions.
• Nausea and vomiting may occur, especially when narcotics are used.
• Special attention should be paid to the fluid intake to ensure adequate hydration.

Example of post sedation instructions to the parent or caregiver

DOCUMENTATION

• Meticulous and accurate documentation of the sedation experience is imperative.

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• In the event of an adverse reaction, the best insurance is an accurate, clear, continuous, documented account of what occurred before, during, and after the encounter.
• Documentation before treatment
• Documentation during treatment
• Documentation after treatment

Documentation before treatment

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1. Proper adherence to food and liquid intake restrictions
2. The preoperative health evaluation, including the patient's health history and a complete physical assessment along with the patient's current weight, age, and baseline vital signs
3. Name and address of the physician who usually cares for the child
4. A note as to why the particular method of management was chosen
5. The presence of informed consent
6. The delivery of instructions to the caregiver.

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• Before the sedation a time out should be performed – to confirm patients name, procedure to be performed and the site of procedure – should be documented in the record.

Documentation during treatment

• Appropriate vital signs should be recorded as they are assessed.
• Timed notations regarding the patient's appearance should be included.
• The type of drug, the dose given, and the route, site, and time of administration should be clearly indicated.
• If a prescription is used, either a copy of the prescription or a note as to what was prescribed should also be a part of the permanent record.

Documentation after treatment

• The patient should be continuously observed in an appropriately equipped recovery area.
• Direct observation until respiratory and cardiovascular stability have been ensured.
• The patient should not be discharged until the presedation level of consciousness or a level as close as possible for that child has been achieved .
• At the time of discharge, the condition of the patient should be noted.

DISCHARGE CRITERIA

• Cardiovascular function is satisfactory and stable.
• Airway patency is uncompromised and satisfactory.
• Patient is easily arousable and protective reflexes are intact.
• State of hydration is adequate.
• Patient can talk, if applicable.
• Patient can sit unaided, if applicable. Patient can ambulate, if applicable, with minimal assistance.
• If the child is very young or disabled, incapable of the usually expected responses, the presedation level of responsiveness or the level as close as possible for that child has been achieved.
• Responsible individual is available.

SEDATION TECHNIQUES

INHALATION ROUTE

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• Rapid onset and recovery.
• Immediate absorption of drug occurs from pulmonary alveoli into the systemic circulation.
• Titration of sedative effect can be easily achieved.
• Safest route
• Mask application is needed for administration of sedative agent, patient compliance questionable in young and uncooperative patient.

ORAL ROUTE

• Popular mode of administration in children
• Simple safe, convenient and most economical.
• Minimizes need for syringes, needles and trained personnel.
• Available as tablets, capsules, syrups.

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Disadvantage

• Delayed onset of action
• Absorption of drug potentially erratic and incomplete.
• Inability to titrate the drug level.

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SUBMUCOSAL ROUTE

• Deposition of drug beneath the mucosa.
• Site of choice – buccal vestibule.
• Onset of action between that of intramuscular and intravenous routes.
• The local anaesthetic required for pain control of the procedure should not be given in the same area after the injection of the sedative drug because the action of vasoconstrictor will slow the uptake of the sedative drug.
• Drugs administered by this technique include narcotics meperidine and fentanyl.

INTRAMUSCULAR ROUTE

• Painful, invasive and one of the most unpleasant routes of drug administration.
• Can be used in patients who suffer to take medication. Patient can be momentarily restrained for the administration.
• Injection site – vastus lateralis muscle on anterior thigh (safest for small children), upper outer quadrant of the gluteus maximus muscle and middle of the posterior lateral aspect of the deltoid muscle.

Disadvantage

• Prolonged time required to reach peak effect.
• Lack of reversibility
• Titration of drug difficult.

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INTRAVENOUS ROUTE

• Rapid onset and rapid weaving off of the drug
• Drug titration is easy
• Continuous intravenous infusion provides steady level of sedation.

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DISADVANTAGE

• Venepuncture is difficult to accomplish in the very young or the combatant child – due to smaller seen size and availability.
• Possibility of phlebitis, hematoma at the site of injection.
• Need for continuous monitoring
• Reversal of the effect not so rapid
• Needs trained personnel.

TECHNIQUES OF CONSCIOUS SEDATION

• Two types
• Inhalation
• Systemic
• Inhalation agent commonly used is nitrous oxide ( relative analgesia).
• Systemic agents are administered by various routes.

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INHALATION SEDATION – NITROUS OXIDE AND OXYGEN SEDATION

• 85% of pediatric dentists use nitrous oxide and oxygen for sedation of patients.
• Most frequently used sedative agent.
• Sweet-smelling, colorless, inert gas.
• It is compressed in cylinders as a liquid that vaporizes on release.
• The gas is nonflammable but will support combustion.

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HISTORY

OBJECTIVES OF NITROUS OXIDE SEDATION

• Reduce or eliminate anxiety
• Reducing untoward movement and reaction to dental treatment
• Enhancing communication and patient cooperation
• Raising the pain threshold
• Increase tolerance for longer appointments
• Aiding in treatment of mentally or physically disabled or medically compromised patient.
• Reducing gagging
• Potentiating the effective of sedatives

AAPD. Guideline for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures - 2016

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INDICATIONS

• Ease anxiety, fear in children especially “needle phobia”.
• Reduce untoward movement and reactions to dental procedures.
• Create hypnotic state with fully conscious patient.
• Increase childs tolerance for longer appointments
• Increase pain threshold
• Enhance effect of sedative premedication thereby reducing the need for GA.
• Aiding in treatment of the mentally/ physically disabled or medically compromised patient
• Reducing gagging.

CONTRAINDICATIONS

Only relative contraindications ( Sorenson & Roth 1975)

• Acute upper respiratory tract infection.
• Mild rhinitis or cold if it blocks nasal passage.
• Severe obstructive respiratory disease.
• Children having pschychatric or nerologic disorder (N2O potentiate all sedative or hypnotic drugs)
• Not used as a substitute for LA or behaviour modification when dentist is unable to diagnose childs behaviour (siegel 1972)
• Maxillofacial deformities that prevent nasal hood placement

PHARMACOKINETICS

• Nitrous oxide is slightly heavier than air, with a specific gravity of 1.53
• Blood to gas partition coefficient of 0.47.
• Low solubility in blood - rapid onset and recovery time.
• Saturated in blood within 3 to 5 minutes following administration and is physically dissolved in the serum (26% of inhaled gas).
• No biotransformation - gas is rapidly excreted by the lungs.
• Very small amounts may be found in excreted body fluids and intestinal gas.

PHARMACODYNAMICS

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• Weakest of all inhalation agents, with a minimum alveolar concentration of 105.
• The minimum alveolar concentration of an inhalation agent is a measure of its potency.
• 30% and 50% - relaxed, somnolent patient who may appear dissociated and easily susceptible to suggestion.

• Amnesia may occur in some patients, but there is little alteration of learning or memory.
• >60% - discoordination, ataxia, giddiness, and increased sleepiness.
• It is not recommended that concentrations >50% be used in dental practice.
• Nitrous oxide is non irritating to respiratory tract and can be given to patients with asthma without fear of bronchospasm.

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EQUIPMENT

• Several manufacturers - safe delivery of nitrous oxide–oxygen mixtures for use in conscious sedation in the dental office.
• The machine should be of the continuous-flow design, with flowmeters capable of accurate regulation.
• A fail-safe mechanism that provides automatic shutdown if oxygen falls below 25% and audible and visual alarms that are activated by oxygen failure.
• There should be a flush lever for easy and immediate flushing of the system with 100% oxygen.

• Mobile, self-contained units are available, as well as those operating from a central supply.
• A major safety consideration with either type is the presence of a good pin-indexed yoke system to absolutely prevent crossover of the cylinder hookup.
• One should be continuously aware of the danger of crossed lines or cylinders.
• Such crossover becomes possible when office renovations are done and when fittings wear with age and use.

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• Gas cylinders color coded
• Green- O2
• Blue- N2O
• 2 sizes
• Small – portable use, D or E approximately 950 – 1596L
• Large – size G or H approximately 12000,- 16000L
• Packed by compression of gas in liquid form.
• Regulator designed to maintain a constant pressure.

• An 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 should be vented to the outside to prevent dispersal of gases to other areas of the office or building.
• Nasal hoods should be of good design and should be available in pediatric and adult sizes to ensure adequate fit, which further reduces leakage.

TECHNIQUE

• After a thorough inspection of the equipment, the mask should be introduced to the patient - should be carefully placed over the nose.
• The delivery tubes are tightened behind the chair back in a comfortable position.
• The bag is filled with 100% oxygen and delivered to the patient for 2 or 3 minutes at an appropriate flow rate, typically between 4 and 6 L per minute.

• With an appropriate flow rate, slight movement of the mixing bag should be apparent with each inhalation and exhalation.
• With too high a flow rate - bag overinflated - leakage will occur from around the mask.
• In this instance, the flow rate should be adjusted downward.
• Too low a flow rate - deplete the bag of mixed gases.
• Once the proper flow rate is achieved, the nitrous oxide introduced - 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.

• The sensations - best described as a floating, giddy feeling with tingling of the digits.
• The eyes will take on a distant gaze with sagging eyelids.
• When this state is reached, the LA 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, and the contemplated procedure carried out.

• The dentist should communicate with the patient throughout the procedure, paying particular attention to the maintenance of an open, relaxed airway.
• The level of nitrous oxide may be periodically reduced to determine the minimum level required for that patient.
• This should be recorded for future reference.
• An emesis basin should be readily available, and in the event that 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 by reverse titration.
• Once the sedation is reversed, the patient should be allowed to breathe 100% oxygen for 3 to 5 minutes ( prevents diffusion hypoxia)
• The patient should be allowed to remain in the sitting position- dizziness on standing.
• The patient is now ready for discharge.
• Even though psychomotor effects return to normal within 5 to 15 minutes, it is not advisable to allow teenage patients to drive themselves home from the appointment.

Advantages

• Cost effective alternative to GA
• Nitrous oxide sedation has minimal effect on cardiovascular and respiratory function and the laryngeal reflex.

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Disadvantage

• Lack of potency
• Dependence on psychological reassurance
• Inteference of the nasal hood with injection to anterior maxillary region.
• Need for patient to be able to breathe through the nose.
• Nitrous oxide pollution and potential occupational exposure health hazards.

Adverse effects and toxicity

• Most common – Nausea and vomiting – due to
1. Overdosage
2. Prolonged administration
3. Pre existing GI infection
4. Impurities in the delivery system.
• Incidence increases
• With concertrations in excess of 50%
• Lenghty procedures
• Rapid fluctuation in concentration
• Rapid induction and reversal

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• Cohen 1980 defined chronic exposure to nitrous oxide as greater than 8 hours a week – Neurotoxicity, impotence, renal and liver toxicity, spontaneous abortion and decrease in fertility.

Chronic exposure kept minimum by (whitcher et al 1978)

• Eliminating leakage in the system
• Limiting the mouth breathing or speech by patient during use.
• Providing adequate circulation of air inside the room.
• Reducing the level of nitrous oxide concentration to 50 ppm in the breathing zone of the dental personnel.
• Double nasal mask – reduces residual nitrous oxide by 97%.
• Scavenging mask.

DRUGS USED FOR CONCIOUS SEDATION

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1. Antihistamine ( hydroxyzine, promethazine, diphenhydramine)
2. Benzodiazepines ( diazepam, midazolam)
3. Benzodiazepine antagonist ( flumazenil)
4. Sedative hynotics (barbiturates, chloral hydrate)
5. Narcotics ( meperidine, fentanyl)
6. Narcotic antagonist ( naloxone)
7. Miscelleneous – Propofol, ketamine, dexmedetomidine

ANTIHISTAMINES

HYDROXYZINE (Atarax, Vistaril)

• Antihistamine with mild sedative and antiemetic properties.
• Rapidly absorbed from the gastrointestinal tract.
• Clinical effect - 15 to 30 minutes, peak levels at 2 hours and a mean half-life of 3 hours.
• Administration - oral route.
• Intramuscular injections must be deep in a large muscle mass.
• Care must be exercised in using this drug in a small child.
• The drug should not be injected subcutaneously or intravenously because of potential tissue necrosis and hemolysis.

ADVERSE REACTIONS:

• Extreme drowsiness
• Dry mouth
• Hypersensitivity

DOSAGE:

• Oral—1 to 2 mg/kg
• Intramuscular (IM)—1.1 mg/kg

PROMETHAZINE (PHENERGAN)

• A phenothiazine with sedative and antihistaminic properties.
• Introduced in 1946
• Potentiates the effect of other CNS depressants

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PHARAMACOKINETICS

• Route – oral, rectal, IM, IV.
• Well absorbed after oral ingestion.
• Onset is within 15 to 60 minutes, with a peak at 1 to 2 hours and a duration of 4 to 6 hours.
• Metabolized in liver.
• Excreted in urine

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DOSAGE:

• Oral/IM—0.5 to 1.1 mg/kg
• Maximum recommended single dose is 25 mg

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ADVERSE REACTIONS:

Dry mouth, blurred vision, thickening of bronchial secretions, mild hypotension, extrapyramidal effects.

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PRECAUTIONS

• Should be used with caution in children with a history of asthma, sleep apnea, or a family history of sudden infant death syndrome.

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CONTRAINDICATIONS

• Phenothiazines lower the seizure threshold and should be avoided in seizure-prone patients.

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DIPHENHYDRAMINE (BENADRYL)

• An antihistamine with sedative properties.
• Produces a mild sedative effect but has additive effects with other CNS depressants.

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PHARMACOKINETICS

• Rapidly absorbed through the gastrointestinal tract
• Maximum effect in 1 hour
• Duration of 4 to 6 hours.
• Metabolized by the liver and completely excreted in urine - 24 hours.

ADVERSE REACTIONS:

• Disturbed coordination
• Epigastric distress
• Thickening of bronchial secretions

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DOSAGE:

• Oral, IM, or intravenous (IV)—1.0 to 1.5 mg/kg
• Maximum single dose is 50 mg.

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DIAZEPAM (VALIUM)

• Depresssant action - reticular activating system and on limbic system, thalamus and hypothalamus.
• Centrally acting muscle relaxant.
• Anticonvulsive property
• Causes amnesia
• No analgesic or antiemetic property.

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PHARMACOKINETICS

• Lipid soluble and water insoluble.
• Rapidly absorbed from the gastrointestinal tract, reaching peak at 2 hours.
• Half-life of 20 to 50 hours.
• After intravenous administration, diazepam is redistributed within 30 to 45 minutes, and the patient seems not to be sedated although free from anxiety.
• The patient should not be considered recovered from the drug.
• Stored drug can be redistributed to the CNS by a fatty meal consumed some time later and the patient will suddenly feel resedated.
• This is referred to as the rebound effect.

ROUTES:

• Oral , rectal, IV

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DOSAGE:

• Oral or rectal—0.2 to 0.5 mg/kg
• Max single dose 10mg
• IV—0.25 mg/kg

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ADVERSE REACTIONS

• Ataxia
• Prolonged CNS effects

MIDAZOLAM

• 3 times more potent than diazepam
• Potent anxiolytic, anterograde amnesia, hypnotic, anticonvulsant, skeletal muscle relaxant & sedative.
• Fast recovery time.

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PHARMACOKINETICS

• High water solubility.
• Packaged in an acidic solution at a pH of 3.3, a state in which the drug is water soluble.
• Once the drug enters the blood, which has a pH of 7.4, the chemical structure changes to an active form with high lipid solubility.
• Lipid solubility is among the highest of all benzodiazepines.

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PHARMACOKINETICS

• After intravenous administration, sedation occurs in 3 to 5 minutes.
• Recovery occurs in 2 hours but is variable and may require up to 6 hours for complete return to baseline values.
• There is no rebound phenomenon from metabolites.
• Midazolam can also be given effectively intramuscularly.
• Midazolam is effective - orally and is available as a syrup.
• Approximately 50% to 65% of the oral dose will go through first-pass hepatic metabolism.
• Onset of action when given orally is between 20 and 30 minutes with an elimination half-life of 1 to 4 hours, which provides approximately 30 minutes of working time.
• Oral administration is indicated primarily for anxious patients requiring relatively short dental procedures.
• As a single agent, it should not be used to control combative behavior.

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ADVERSE REACTIONS

• Respiratory depression with higher doses.
• There is also a dose-related risk of apnea, which is believed to be influenced by the rapidity with which the drug is administered."- Apnea is more likely to occur when midazolam is used with narcotics.'

DOSAGE:

• Oral—0.25 to 1.0 mg/kg to a maximum single dose of 20 mg
• IM—0.1 to 0.15 mg/kg to a maximum dose of 10 mg
• IV— 0.05 to 0.10 mg/kg
• Nasal – 0.2 to 0.4mg/kg

BENZODIAZEPINE ANTAGONIST – FLUMAZENIL (ROMAZICON)

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• Flumazenil is a benzodiazepine receptor antagonist.

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• The drug selectively inhibits the CNS effects of the benzodiazepines by a competitive, high-affinity interaction with benzodiazepine receptors.

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• The drug is recommended for intravenous use only and is not recommended for use in children younger than 18 years of age

• For reversal of conscious sedation, the initial dose should be 0.2 mg given over 15 seconds.

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• Should the desired level of consciousness not occur after waiting an additional 45 seconds, another dose of 0.2 mg should be administered and dosing repeated at 60-second intervals to a maximum total dose of 1 mg.

• Onset of reversal is usually seen within 1 to 2 minutes

BARBITURATES

• Derivatives of barbuturic acid.
• Popular till 1960’s and called as protype of CNS depressants.
• As premedicants in pediatric dentistry, the most frequently prescribed agents are secobarbital and pentobarbital.
• The use of barbiturates in pediatric dentistry has been limited for two reasons:
• Reputed ability to induce paradoxic excitement
• Limited therapeutic dosage range.

Action on CNS

• Sedative dose slightly depress CNS
• Act on reticular activating system.
• Produces sleep similar to the physiologic sleep but rapid eye movement phase is reduced.
• Does not produce analgesia.

Action on CVS

• Hypnotic dose – no effect.
• High dose - Decrease contractility force

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Action on respiratory system

• Respiratory depressant
• Supress hypoxic and chemoreceptor response to CO2.

PHARMACOKINETICS

• ROUTES – oral, rectal, IM, IV
• Oral route most common, absorption rapid if given in empty stomach.
• Termination by resedation, metabolism, excretion
• Dose 30 – 100mg

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COMMERCIAL NAME –

• Luminal 100mg tab
• Phenobarbitone sodium (200mg/ml inject)

ADVERSE EFFECTS

• Hangover
• Repeated use – tolerance and dependence
• Idiosyncrasy produces excitement
• Acute poisoning

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CHLORAL HYDRATE

• Widely used drug for pediatric sedation.
• Used for minimum to moderate sedation.
• Robins 1976 – combination with promethazine most effective.

PHARMACOKINETICS

• Routes – Oral, rectal
• Well absorbed from GIT
• Metabolised in liver
• Excreted in urine
• Onset 30-60 min
• Duration 4-8 hrs
• Half life - 8-11 hours

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DOSAGE

• Oral - 25 – 50 mg/kg.

SIDE EFFECTS

• Patient may become irritable and disoriented.
• Asthmaticus are sensitive to respiratory depressant action.
• Has narrow margin of safety, not to exceed 50mg/kg.
• Gastric irritation, nausea, vomiting, exciement, delirium.
• In large doses – myocardial depression and arrhythmias.

NARCOTICS

• Used in sedation for their primary action of analgesic.
• Site of action – opoid receptor of CNS increase the pain threshold
• If used as a sedative – side effects such as respiratory depression, apnea and hypoxia.
• Should be accompanied by a drug that produces sedation as primary effect.
• Not used as a substitute for LA.

Side effects

• Nausea and vomiting
• High dose – respiratory depression
• Potentiates other CNS depressants

Meperidine (Demerol)

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• A synthetic opiate agonist
• ROUTES – oral, IM, IV
• Peak 1 hr
• Duration 4 hrs

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DOSAGE –

• Oral, SC, or IM—1.0 to 2.2 mg/kg,

not to exceed 100 mg

SIDE EFFECTS

• High doses that lead to an accumulation of normeperidine, a primary metabolite of meperidine, have resulted in seizures.

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PRECAUTIONS

• Used with extreme caution in patients with hepatic or renal disease or history of seizures.

FENTANYL

• A synthetic opiate agonist.
• It is a very potent narcotic analgesic.
• When it is used with other CNS depressants, the dose should be reduced.
• Can be used in combination with orally aministered diazepam and nitrous oxide.

PHARMACOKINETICS

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• Rapid action after SM or IV injection.
• Onset 7 to 15 minutes.
• Duration 1 – 2 hours
• Metabolized in liver
• Excreted in urine
• Dose – 0.002 to 0.004 mg/kg.

• Fentanyl in moderate doses of 2 to 10 microgram/kg or higher doses when given rapidly intravenous can produce skeletal muscle rigidity called “stiff chest syndrome.”

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• Fentanyl lacks histamine release and suppresses the stress response associated with surgery or invasive procedures and also depresses the respiratory center in the brainstem so that normal response to hypoxia and hypercarbia is reduced.

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NARCOTIC ANTAGONIST (NALOXONE)

• A semisynthetic opiate antagonist used for the sole purpose of reversing the effects of narcotic drugs.
• Naloxone is a pure antagonist, with no agonist activity even in large doses.

PHARMACOKINETICS

• SC, IM - 2 to 5 minutes
• IV - 1 to 2 minutes intravenously.
• Duration of reversal - 45 minutes

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DOSAGE:

• Initial dose: 0.01 mg/kg;
• Subsequent doses: 0.1 mg/kg (2 mg maximum) every 2 to 3 minutes

PROPOFOL

• Sedative and hypnotic properties
• Oil in state at room temperature and is insoluble in aqueous solution.
• Onset of action – 30 to 90 seconds (Rapid)
• Dosage – initial dose 1-2mg/kg IV
• Maintenance dosage needed to achieve satisfactory sedation, ranging from 3 to 4 mg/kg/h

• Recovery from the drug faster – 2-3 minutes
• Ideal agent for deep sedation
• No analgesic effect – should be used in adjunt with other medications – fentanyl, ketamine for painful procedures.

• Propofol causes pain on injection – administer small dose lidocaine 1mg/kg of the drug through IV line such as antecubital vein.
• Recently involved agent in death of Michael Jackson due to overdosing.

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Ketamine

• Dissociative anaesthetic agent – profound analgesia, immobility, amnesia with light sleep and feeling of dissociation from ones own body and surroundings.
• Site of action – thalamus and cortex
• Classified as GA as the patient under its influence is uncapable of making appropriate responses to verbal command or physical stimulus.

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• Ketamine has advantages over other drugs in its relative cardiovascular steadiness and restricted affect on the respiratory mechanics.
• It is a dose-related cardiovascular stimulant.
• Even in children with congenital heart disease, it caused clinically only minor increases in heart rate and mean pulmonary artery pressure during catheterization.

DOSAGE –

• Oral – 5-6 mg/kg
• IM – 3–4 mg/kg
• IV – 1 to 2 mg/kg

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Side effects

• Respiratory depression and arrest
• Delirium and hallucination
• Tachycardia and increase in BP

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MONITORING DURING SEDATION

• PULSE OXIMETRY – for O2 saturation
• CAPNOGRAPHY – for end tidal CO2 measuring
• ECG and noninvasive BP – CVS
• Temperature
• Precordial stethoscope -  assessment of heart tones and the quality of breath sounds

MANAGEMENT OF COMPLICATIONS

1. Airway obstruction
2. Vomiting
3. Respiratory depression
4. Bradycardia
5. Hypotension

1. AIRWAY OBSTRUCTION

• Extend the neck of the child
• Clear the mouth with your fingers and then suction
• Perform oral airway maintenance
• Give O2 by mask using N2O analgesic machine. Use O2 only.

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2. VOMITING

• Place the head down and turn to one side
• Suction the pharynx and oral cavity
• Establish clear airway.
• Metaclopramide – 0.15mg/kg IV

3. RESPIRATORY DEPRESSION

• Be certain the airway is clear
• Reverse narcotic with antagonist
• Ventilate with positive pressure
• Bradycardia – give 0.5 mg of atropine IV IM
• Give positive pressure oxygen

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HYPOTENTION

• Give positive pressure oxygen
• Put patient in supine position