Anesthesiaworld

Introduction

The demand for sedation out side the OT has increased significantly over the last decade.Children undergoing dental treatment is one of the important sub populations requiring sedation.

[su_note note_color=”#fdfdd1″]Understanding sedation better

• Concepts: Physiology and Pathophysiology
• Advantages
• Definitions
• Drugs
• Equipment
• Patient selection
• Indications and contraindications
• Patient evaluation
• Risk stratification
• Preparation
• Sedation scores
• Conduct of sedation
• Complications
• Discharge criteria
• Documentation
• Special categories
• Desired professional attributes
• Ideal pediatric dental set up
• Summary[/su_note]

Concepts: physiology and Pathophysiology

Life is dependent on uninterrupted supply of oxygen and elimination of carbon dioxide through a patent airway.The airway patency is due to muscle tone and protective reflexes,both of which are intact in awake state.
Sedation with any drug depresses the level of consciousness,which worsens as the level of sedation deepens.The consequence is reduction of muscle tone and loss of protective reflexes,both of which predispose to airway obstruction.When the airway is obstructed,hypoxia is the result.In addition,sedatives directly can cause respiratory depression and worsen the hypoxia.Once airway obstruction or hypoxia develops it sets in a vicious cycle,wherein,airway obstruction worsens hypoxia and vice versa.Hence,the importance of early recognition and intervention.
Hypoxia,defined as oxygen saturation of less than 90% as shown by pulse oximetry,can lead to cerebral ischemic damage if not reversed within 3 minutes.
Suppression of protective reflexes also predispose to aspiration of gastric contents,which is rare,but associated with high morbidity and mortality.
Lastly,sedation,has potential to cause cardiovascular collapse.Cardiac arrests in otherwise healthy children undergoing dental sedation have been reported.In children cardiac arrest is almost always due to hypoxia,and is preceded by bradycardia.
Advantages
There are several advantages associated with a properly conducted sedation.They are
• reduced anxiety for the child and hence better cooperation
• reduced anxiety for parents
• improved quality of treatment
• reduction in the number of sittings required for treatment
Availability of better quality of drugs with superior safety profile have also significantly contributed to increased utilization of sedation.

Definitions

Depth of sedation is classified based on the effects on/changes in various body systems and functions.

Minimal sedation or Anxiolysis

• Minimal depression of consciousness
• Protection reflexes are maintained
• Patent airway maintained independently and continuously
• Normal response to tactile stimulus or verbal commands
• Ventilation is unaffected
• Hemodynamic stability
• Minimal impairment of cognitive function and coordination

Moderate sedation

• Purposeful response to tactile or verbal command
• Protective reflexes are maintained
• Patent airway usually maintained
• Spontaneous ventilation adequate
• Hemodynamic stability maintained
• Cognitive function impaired

The terminology conscious sedation is no more used in many classifications,but retained in pediatric dental sedation. It is a moderate depression of consciousness where continuous verbal contact with patient is maintained.
Clinically,it may be difficult to differentiate between conscious and moderate sedation.

Deep sedation

• Significant depression of level of consciousness
• Purposeful response only to deep and painful stimulus
• Potential for airway obstruction,intervention may be required(see below)
• Potential for hypoventilation
• Hemodynamic stability may be affected and result in hypotension.

General anesthesia

• Complete(and controlled) loss of consciousness
• No response to painful stimuli
• Airway intervention always required
• Potential for hemodynamic stability

Remember

1. Any particular level of sedation is not constant and can change to lower or higher level depending on various factors:dose,duration,stimulation,etc.Hence the term,sedation continuum is used to describe different levels of sedation
2. Potential for complications increase as depth increases
3. More intense monitoring required as the depth increases
4. The difference between deep sedation and general anesthesia is minimal and a deeply sedated patient can easily reach the level of general anesthesia.

Drugs

Knowledge of drugs is one of the keys to safe sedation in children.
Three categories of drugs are commonly used:sedatives,adjuvant drugs and emergency drugs.
Individual drugs are described in alphabetical order In each category

Sedatives

There are large number of drugs in this category.Here,the focus is on the drugs which are routinely used.

Groups of sedatives:
1. Alpha 2 agonists
2. Anesthetic drugs:ketamine,propofol
3. Benzodiazepines:midazolam
4. Opioids:fentanyl,alfentanyl

Dexmedetomedine

It is a highly specific alpha2 agonist,causes reduction in sympathetic flow in the central nervous system.It has become very popular for sedation because 1)the sedation resembles normal sleep 2)lack of respiratory depression 3)produces amnesia 4)excellent quality of recovery which is without hangover and also rapid.
Each 1ml ampoule contains 1mg/ml
Dose:1-2mcg/kg, intravenous,over 10min followed by 1mcg/kg/h infusion
Main adverse effects are bradycardia and hypotension.Pretreatment with inj glycopyrrolate IV,0.1 -0.2mg prevents the bradycardia,but sometimes can cause hypertension.

Fentanyl

Short acting,synthetic opioid and a mu agonist,nearly 100 times more potent than morphine.
Available as 50mcg/ml,2 ml ampoule.
Dose 1-2 mcg/kg intravenous.
Advantage:Potent analgesic.Also,it can be combined with midazolam or propofol.A reduced dose of drug is used when combined with another sedative.
Disadvantages/adverse effects:respiratory depression,nausea and vomiting,pruritis

Ketamine

Ketamine is a phencyclidine derivative and NMDA(N Methyl D Aspertate) receptor antagonist.Produces dose dependent sedation and analgesia,higher doses producing what is characteristically called “dissociative anesthesia”.
Available as ampoules or vials containing 50mg/ml of ketamine hydrochloride.
For intravenous sedation can be diluted to 5mg/ml with sterile water.
Route:IV,IM,oral
Intravenous is preferred if IV access is possible as the onset of action is rapid and recovery is also faster.A dose of 0.25-0.5mg/kg produces analgesia and 0.75-1mg/kg produces sedation as well.Higher doses will produce general anesthesia.Nystagmus and involuntary movements are seen with ketamine.
Intramuscular route with a dose of 2-3mg/kg can be used for sedation in uncooperative children.

Midazolam

Short acting benzodiazepine,water soluble preparation but is highly lipid soluble once inside the body.Produces dose dependent anxiolysis,amnesia,sedation and anesthesia.Also,increases the threshold for local anesthetic toxicity and has inherent anticonvulsant property.
Usually available as 1mg/ml preparation in 5ml vials.a preparation containing 5mg in 1 ml is also marketed.Hence,one has to carefully ascertain the strength of the drug in the preparation.

Propofol

Not recommended for use by non anesthesiologists,due to potential risk of airway obstruction and cardiac depression.
It is an excellent sedative in trained hands as it provides a good quality of sedation in sub anesthetic doses.The recovery profile of propofol is better than any other sedative.Moreover,propofol has anti emetic and anti pleuritic effects.
Dose for sedation is 0.5 to 1mg/Kg followed by 5-10mg incremental bolus doses or 50mcg/kg/min infusion.

Oral sedation

Oral route can be used in hyperactive children,in the dose of 5-7 mg/kg,which produces sedation in about 20min.Oral ketamine can be combined with midazolam0.5mg/kg,for a better quality of sedation and recovery.Intra venous preparation is used for oral administration.
Ketamine administration is often preceded by inj atropine or glycopyrrolate to reduce secretions.Alternately,atropine can be combined with ketamine when it is administered orally.
For oral route,the same IV preparation is used for all these drugs.

Equipment

Availability of proper equipment and their preparation is as important as other factors.
Following is list of the equipment

I For oxygen administration and airway management
• Oxygen source;cylinder or central supply
• Oxygen face mask and nasal prongs
• Self inflating bag(AMBU bag)
• Laryngoscope
• Endotracheal tubes
• Oral and nasal airways
• Anatomical face masks
• Stylet
• Syringe to inflate the cuff
• Magill forceps
• Supraglottic airway device;laryngeal mask airway or I Gel

Others
IV cannula
IV fluids

Many photos of equipment:1)all airway equipment(laryngoscope,airways,endotracheal tubes and Magill forceps 2)pediatric Ambu bag with reservoir and oxygen tubing and 3)others like IV cannula,IV ser,oxygen flow meter,etc 4)suction apparatus 5)separate photos of laryngoscope ,pediatric endotracheal tubes and mask 6)different sizes of IV cannula used in children.

Indications and contraindications

Indications

1. Older children,at least above 4 years.
2. Superficial dental procedures suitable for performing in dental clinics
3. Short duration procedures,not more than 45 min to 1 hour.
4. Healthy children of ASA I and II physical risk status

Contraindications

1. Small children
2. Long and extensive procedures
3. Children of ASA III and IV category
4. Children with difficult airway
5. Children at risk of aspiration
6. Uncooperative children or extreme anxiety
7. Excessive parental anxiety
8. Lack of suitable equipment and personnel

There is no fixed age as indication or contraindication for sedation.But it is preferable to consider all children below 3-4 years for general anesthesia.

Pre procedure evaluation

No child should be subjected to sedation without proper pre-procedure assessment.
History
• Birth history and milestones
• Co morbidity
• Treatment history
• Snoring
• Respiratory infection in the recent past.
Obstructive sleep apnoea and childhood obesity are the emerging problems in pediatric Anaesthesia and sedation,as both can co exist and increase risk of complications.

Clinical examination
• General appearance
• Pulse,respiration
• Cardiovascular system
• Airway examination
• Vascular access

Investigations and review of past medical records
Both these steps are required only when there is indication.In other words,a healthy child who has been active and without any respiratory infection,need not undergo any investigation.
When a rescheduling of procedure required?
• Presence of active respiratory infection,especially lower respiratory infection as indicated by wheeze,coughing,fever etc
• Dyspnoea or limitation of activities
• Cyanosis
• Any significant positive finding in history and clinical examination
Who should do the pre procedure assessment?
• If the child is healthy and older,procedure is superficial and plan is for minimal sedation or nitrous oxide sedation,then evaluation by a well informed pedodontist should be sufficient.
• If the child is posted for any procedure requiring moderate or deep sedation,younger age and has any positive finding on initial assessment,then a review by anesthesiologist would be appropriate as his/her presence or involvement would be required.
When pediatric consultation is required?
• Young children
• Presence of symptoms such as wheeze,dyspnoea,or any suspected abnormal clinical features
• Children with delayed milestones and differently abled children
• Children with known congenital heart disease
• As a part of institutional protocol
__________________________________________________________________
Risk stratification
ASA Physical status
This assigns a patient to class 1 to 5 and they are
Class 1 : otherwise normal child
Class 2 : mild systemic disease,well controlled.Eg :well controlled bronchial asthma ,asymptomatic congenital heart disease,obesity, etc
Class 3 : moderate systemic disease Eg:child with asthma with frequent attacks,but without active bronchospasm at present
Class 4
Class 5
Comments
1)In general,children with risk status of class 3 and above should undergo treatment under general anesthesia or in advanced sedation centres or in a hospital based set up.They also need more extensive pre procedure evaluation,consultation and preparation.
2)ASA physical status does not take into consideration of individual organ affected by a disease,it only considers the effect of the disease on functional status of the individual.
For eg:A child having well controlled bronchial asthma is ASA class 2 risk and a child of the same age having anemia also belongs to same category.But,when it comes to sedation,the former child is at higher risk of developing bronchospasm than the latter.
3)Airway management is an important management(actual or potential) aspect in sedation.A child,irrespective of ASA class can have an abnormality of airway;a difficult airway or rarely a compromised airway.
Preparation
Proper planing and preparation is another component of successful sedation management.
Preparation of the patient
Fasting
6-8 h of fasting for solids and milk and 3h of fasting for clear fluids(non particulate),ensures complete gastric emptying and minimizes risk of aspiration.
Excessive fasting or withholding clear fluids also for eight hours can lead to dehydration,Increaed anxiet,irritability etc.hence,good practice is to allow or encourage the child to have clear fluids like water or coconut water upto 3h prior to procedure to have a more cooperative and better hydrated child.
Premedication
Premedication can be given by oral or intramuscular route thought the latter is better avoided as far as possible.Various suggested regimens are
a)oral midazolam 0.5mg/kg ,20-30min prior to procedure.It can be. Of boned with oral ketamine 4-5mg/kg and atropine 0.6mg.For all these drugs,the contents of IV preparation can be used.
b)Intramuscular glycopyrrolate 0.2mg 30min before procedure,if ketamine is the sedative as it increases respiratory secretions.
Preparation of the equipment and environment
All the equipment,described above,should be checked and kept ready alongwith monitor and suction.Availability of reliable and qualified assistant is very useful and mandatory for moderate sedation.
Conduct of sedation
There are several unique features of dental sedation :
[su_box title=”Unique features of Sedation” box_color=”#dcfcbd” title_color=”#000000″]• Patients are young children
• Area of procedure,mouth,is a part of airway and shared with anesthesiologist in moderate to deep sedation
• Bleeding
• Continuous irrigation
• Risk of foreign body aspiration[/su_box]

The most important issue is to ensure patient safety at all times as primary goal and making the patient comfortable so that the dentist can carry on treatment unhindered is the other goal.

Step 1
Ensure : patient has been evaluated,premeditated and consent taken
Ensure: all equipment including monitor are checked and kept ready (see the list)
Ensure: all members of sedation team are present and aware of their responsibilities
Step 2
• Connect the child to monitor and record the baseline SpO2,NIBP and ECG.A normal healthy child has room air SpO2 more than 95% and regular rhythm on ECG.however, irregular rhythm on ECG,sinus arrhythmia,is not uncommon in children and is physiological.
Insert picture of monitor with values obtained from OT and also a video of parameters being continuously displayed
•

Start intravenous access,and preferably fluids by infusion pump.Usually,22G(blue) cannula is used.
pictures of child’s hand with IV cannula in place
Administer the calculated dose of sedative drug in a titrated fashion,observing response to verbal commands,eye lash reflex ,heart rate and pattern of respiration.
——-insert pictures of child at various stages of sedation…..link to video ……..
Ideal depth for most of the procedures,except for very superficial ones in older child,is a moderate sedation where respiration is regular,heart rate stable,airway is maintained without any aid and patient purposefully responds to verbal or gentle tactile stimulus.
Further,continue sedation as required with either intermittent doses or if planned by infusion.
Oxygen can administered by nasal prongs at 2-3l/min

Step 3
At the end of the procedure,continue monitoring till the child is fully awake or recovers to the level of minimal sedation(sedation score value…..).
Shift the child to recovery area and continue to monitor with pulse oximeter till complete recovery

1.
Post procedure care
This is the vulnerable period as the effect of sedation could still be persisting and surgical stimulus is absent.This can result in deterioration of level of sedation.This,combined with the decreased vigilance,explains the vulnerability for complications.

Complications
• Airway obstruction,fall in oxygen saturation(hypoxia),changes in heart rate,especially bradycardia,hypoventilation,aspiration,bleeding,bronchospasm are the important complications during the procedure.
• Respiratory depression leading to hypoventilation and hypoxia
• Cardiovascular complications include bradycardia(first response to hypoxia),tachycardia,hypotension and arrythmia.
Approach to management of complications
• Stop the procedure and call for help if required
• Jaw through and chin lift,airway insertion,if airway obstruction suspected or present
• 100% oxygen with positive pressure ventilation with appropriate size mask
• Treatment of bradycardia,with atropine 0.6mg(1ml,undiluted) intravenous.
• If aspiration is suspected or prsent,then a)aspirated all the solid food particles from mouth b)100%oxygen with positive pressure ventilation followed by endotracheal intubation.Further management as decided by anesthesiologist
——-insert box———–below——
Note
1. Airway obstruction initiates a viscious cycle leading to hypoxia(see Pathophysiology)
2. In children,response to hypoxia is bradycardia,heart rate of less than 60/min
3. Hypoxia is managed with positive pressure ventilation with 100% oxygen followed by inj atropine,0.3mg(weight less than 20kg) or 0.6mg,for weight more than 20kg.Same dose can be repeated if required.Atropine is one of the safe drugs.
4. Arrythmias and tachycardia without hemodynamic instability need not be treated.Sinus arrythmia,variation of heart rate with respiration is physiological in children.
——————–box above———–

Discharge Criteria

• Awake and obeys commands
• Hemodynamically stable,normal oxygen saturation
• Minimal or no nausea and vomiting
• Responsible adult with clear instructions regarding the NPO status and contact details in case of any problems.
Modified Aldrete’s recovery score can be used for assessing level of recovery

Documentation
It is a very important part of overall sedation plan,but mostly neglected.Proper documentation,
1. acts as a reliable source of information
2. helps to analyse the critical incident or complications,if any
3. helps in improving the system by objective analysis
4. helps to understand the patterns of response of children of different categories
5. useful in research
6. is very useful when there is a Medicolegal issue involved.
7. Gives the trends in changes of monitored parameters and trend is more important than a single value
What to monitor and document?
1. Continuos monitoring of ECG,SpO2 and blood pressure
2. Document the baseline value of SpO2 on room air and blood pressure
3. Document SpO2 and blood pressure values every 5 min
4. Document Ramsey’s sedation score every 5 minutes
5. Document any incidents,critical or non critical
When there is a critical incident,use a separated critical incident reporting form and submit it to the appropriate authorities for further discussion,review and follow up action

Special situation and clinical dilemma
Child with infection
A child with active respiratory infection as indicated by fever,cough,wheeze,expectoration etc is contraindication for sedation as incidence of respiratory complications in these patients are unacceptably high.Similarly,when there is active systemic viral or bacterial infection elsewhere also,it is better to reschedule the child for sedation.
However,a child with recurrent or mild upper respiratory infection,as indicated by absence of fever and wheeze,decision for sedation is left to the descretion of the anesthesiologist,who provides sedation.
Child with congenital heart disease(CHD)
CHD is a “generic” term which includes large number of clinical conditions varying from simple,uncomplicated asymptomatic conditions(Eg small ASD,VSD) to complex symptomatic(cyanosis,dyspnoea,failure to thrive etc) conditions such as Fallot’s Tetrology.
This,it is mandatory that these children,suspected of having CHD,should be evaluated by pediatrician,anesthesiologist and other specialists as required before deciding on the suitability of sedation.
Admission to hospital after sedation
• Complications during the procedure associated with hypoxia,bleeding etc
• Severe pain
• Delayed recovery
• Intractable PONV
• Unusual reaction or response to a drug such as anaphylaxis
• Post resuscitation following cardiac arrest
Desired attributes for sedation practice:
Knowledge
• Preoperative evaluation and identification of high risk children
• Ensure compliance with fasting guidelines
• Basics of airway management
• Understanding of equipment for airway management,vascular access etc
• Pharmacology of sedatives and emergency drugs
• Monitoring of the sedated child

Skills
• Vascular access
• Bag mask ventilation
• Airway insertion;oral and nasal
• Basic life support
The sedation units
Independent vs hospital based sedation set ups
Stand alone units(SAU) require higher level of preparedness,equipment and strict enforcement of rules and guidelines.The personnel should be well trained and be able to anticipate,diagnose and manage the complications during the procedures.
Also,SAU,should have tie up with local hospital or emergency services as part of the back up plan to manage unanticipated emergency situations during sedation.

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Summary of Guidelines
Except as noted, recommendations apply to both moderate and
Deep sedation.
1. Preprocedure evaluation
• Relevant history (major organ systems, sedation–anesthesia history,
Medications, allergies, last oral intake)
• Focused physical examination (to include heart, lungs, airway)
• Laboratory testing guided by underlying conditions and possible
Effect on patient management
• Findings confirmed immediately before sedation

2. Patient counseling
• Risks, benefits, limitations, and alternatives

3. Preprocedure fasting
• Elective procedures—sufficient time for gastric emptying
• Urgent or emergent situations—potential for pulmonary aspiration
Considered in determining target level of sedation, delay of procedure, protection of trachea by intubation

4. Monitoring(Data to be recorded at appropriate intervals before, during, and after procedure)
• Pulse oximetry
• Response to verbal commands when practical
• Pulmonary ventilation (observation, auscultation)
• Exhaled carbon dioxide monitoring considered when patients separated from caregiver
• Blood pressure and heart rate at 5-min intervals unless contraindicated
• Electrocardiograph for patients with significant
• Cardiovascular disease
For deep sedation:
• Response to verbal commands or more profound stimuli unless contraindicated
• Exhaled CO2 monitoring considered for all patients
• Electrocardiograph for all patients
5. Personnel
• Designated individual, other than the practitioner performing
The procedure, present to monitor the patient throughout the procedure
This individual may assist with minor interruptible tasks once
Patient is stable
For deep sedation:
The monitoring individual may not assist with other tasks
6. Training
• Pharmacology of sedative and analgesic agents
• Pharmacology of available antagonists
• Basic life support skills—present
• Advanced life support skills—within 5 min
For deep sedation:
• Advanced life support skills in the procedure room
7. Emergency Equipment
• Suction, appropriately sized airway equipment, means of positive-
Pressure ventilation
• Intravenous equipment, pharmacologic antagonists, and basic
Resuscitative medications
• Defibrillator immediately available for patients with cardiovascular disease
For deep sedation:
• Defibrillator immediately available for all patients
8. Supplemental Oxygen
• Oxygen delivery equipment available
• Oxygen administered if hypoxemia occurs
For deep sedation:
• Oxygen administered to all patients unless contraindicated
9. Choice of Agents
• Sedatives to decrease anxiety, promote somnolence
• Analgesics to relieve pain
10. Dose Titration
• Medications given incrementally with sufficient time between doses to assess effects
• Appropriate dose reduction if both sedatives and analgesics used
• Repeat doses of oral medications not recommended
11. Use of anesthetic induction agents (methohexital, propofol)
• Regardless of route of administration and intended level of sedation, patients should receive care consistent with deep sedation, including ability to rescue from unintended general anesthesia
12. Intravenous Access
• Sedatives administered intravenously—maintain intravenous
Access
• Sedatives administered by other routes—case-by-case decision
• Individual with intravenous skills immediately available
13. Reversal Agents
• Naloxone and flumazenil available whenever opioids or benzodiazepines
Administered
14. Recovery
• Observation until patients no longer at risk for cardiorespiratory depression
• Appropriate discharge criteria to minimize risk of respiratory or cardiovascular depression after discharge
15. Special Situations
• Severe underlying medical problems—consult with appropriate
Specialist if possible
• Risk of severe cardiovascular or respiratory compromise or need
For complete unresponsiveness to obtain

References
ASA Physical Status Classification System is reprinted with permission of the American Society of Anesthesiologists, 520 N. Northwest Highway, Park Ridge, IL 60068-2573

Anesthesiology, V 96, No 4, Apr 2002