LA Sheet #12 By Yasmin Hzayyen

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LA Sheet #12 By Yasmin Hzayyen

Post by Sura on 24/12/2011, 12:03 am

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Re: LA Sheet #12 By Yasmin Hzayyen

Post by Shadi Jarrar on 24/12/2011, 12:19 am

بسم الله الرحمن الرحيم

Local Anesthesia

Lecture number 12
(2nd on 21.12.2011)
Dr. Mahmoud Al-Mustafa
Yasmin Hzayyen
SEDATION FOR DENTAL PROCEDURES

*** This sheet contains what's written in the slides… Enjoy!!!

Sedation is a state of controlled depression of consciousness that allows patients to tolerate unpleasant procedures while maintaining adequate cardiorespiratory function and the ability to response purposefully to verbal commands and tactile stimulation, all this is titrable and controllable; as you give more dose the patient is more sedated.

v Dentistry treatment is still one of the most anxiety inducing events in people's lives; a lot of people refuse to go to a dentist! Especially anxious from the needle! There is this study made in the UK (Adult Dental Health Surveys in the united kingdom

( 1988 and 1998)) , that half of the adult population there, is anxious about dental treatment and would certainly avoid it. Dental anxiety is found to affect patient's quality of life including sleeping disturbances, interference with work and interference with personal relationship. Dental anxiety affects both the patient and the dentist; it's hard to deal with that kind of patients.

A survey was made in 1997 into patients' preference found that (65%)of those asked would like to be pain-free but conscious, (56%) would like to be amnesic. Amnesic means that the patient doesn't want to remember the procedure; prospective and retrospective amnesia, when we give the anxiolytic agent we make an anterospective amnesia, this means that the patient forgets everything that happens AFTER taking the drug not before.

**This is what I've found:

v Anterograde amnesia refers to a deficit in encoding new information subsequent to a given and specific event in time ( after taking the anxiolytic agent)

v Retrograde amnesia refers to the loss of information preceding a specific event in time or the onset of brain damage.

From the slides: "A recent survey of general dental practitioners in Scotland:

- 74% felt there was a need for sedation in their practices."

We already talked about stages of anesthesia, here there are again:

1- Stage of analgesia:

Diminished pain perception, verbal contact

maintained, laryngopharyngeal reflexes and

voluntary control Present

2- Stage of uninhibited response (Excitement):

Consciousness lost, verbal contact and voluntary

control lost è uncontrolled, exaggerated, withdrawal

type response to any stimulus

Protective laryngopharyngeal reflexes maintained!

3- Stage of Surgical Anesthesia

4- Stage of Respiratory Arrest



Aim of sedation:

n Achieving anxiolysis and patient cooperation.

n Drugs and techniques used should render unintended loss of consciousness unlikely.

As we said before:

- Local anesthesia è relief of Pain.

- Sedation èrelief of Fear and Anxiety.

- General anesthesia è Relief of Both Pain and Anxiety; the patient is unaware of the whole procedure.

Groups which we prefer to sedate are: children, young adults and anxious adults.

A significant proportion of children remain pre-cooperative despite full utilization of suitable behavior-management techniques. Careful assessment of the child’s level of anxiety is essential.

Only ASA I and ASA II groups should undergo dental sedation in a general dental practice (clinic); sedation is contraindicated for patients with high risk factors in clinics, these patients should be hospitalized to sedate them.

Risk classification:

n ASA I : A normal Healthy patient 0.06-0.08%

n ASA II : A patient with mild systemic disease 0.27-0.40%

n ASA III: A patient with severe systemic disease 1.8 - 4.3%

n ASA IV: A patient with severe systemic disease that is a constant threat to life 7.8 - 23%

n ASA V: Moribund patient who is not expected to survive without the operation 9.4-51%

n ASA VI: A declared brain dead patient whose organs are being removed for donor purposes

n “E” For Emergency surgery

Informed, Written Consent regarding the sedation procedure for a course of dental treatment (By patient or guardian) not only with general anesthesia, we have to explain the procedure and the possibility to shift into general anesthesia (if there were some kind of complications) during the procedure. (It happens in 5-10% sedation cases)



Drugs that are used:

1-Benzodiazepines

2- Neuroleptanalgesia

3- Nitrous Oxide Gas

4- Sedative Anesthetics (I.V Hypnotic drugs)



Benzodiazepines

n Most widely used

n Wide safety Margin

Oral and intravenous formulations are available
Functions:
1- Anxiolytics; relief the anxiety.
2- Sedative (hypnosis) è sleep promotion. (It also helps people who suffer from insomnia)
3- Amnesia (anterograde amnesia).
4- Central muscle relaxant effect (weak relaxants).
5- Anticonvulsant; to subside epilepsy!
Diazepam =Valium

Orally: 2 mg q 8 hours for anxiety or 10-15 mg for premedication 2 hours pre-op
(In Hospital); when the patient is about to have a surgery diazepam is given to decrease any anxiety the patient is having.
Intravenous or intramuscular: painful on injection( not available).

§ Best anxiolytic

§ Poor amnesic

§ Minimal Cardiovascular depression

§ Long Duration of action ( > 4 hours)

§ Active metabolite (that's why it has long duration of action)
Midazolam= Dormicum*

No oral preparation available (but the I.V preparation is sometimes given to children mixed in paracetamol preparation), in some Western countries it is used orally as a juice for children to relax them.

It's the most commonly used anxiolytic agent! As it is given by an intravenous route.

Indications:

- Conscious sedation

- Induction of general anesthesia

Dose:

- For pre-op sedation 0.07 – 0.08 mg/kg 1 hour before procedure I.M injection

- Individualized dose I.V

n Best amnesic , good hypnotic

n Some cardiovascular depression

n Readily produces general anesthesia (if the dosage was high)

n Duration : < 2 hours

n Generally recommended for patients >16 years old (but it's used with children as well)



Temazepam only available orally (not common)

Dose:

- Insomnia: 10 – 30 mg

- Premedication: 10 – 20 mg 90 minutes prior to surgery

n Good Hypnotic

n Short duration < 4 hours

May cause dysphoric reactions in young adults (Dysphoric means a state of dissatisfaction, anxiety, restlessness, or fidgeting)



Antidote for benzodiazepines: Flumazenil (Anexate)

It's given when the patient undergoes a sudden respiratory depression caused by the benzodiazepine, it's necessary to have it in the emergency kit, along with the opioids antidote.

n A specific benzodiazepine antagonist (reverts the action of the medication)

n I.V injection

n Essential requirement anywhere Benzodiazepines are used

n 0.2 mg IV every 15 seconds

n Rapid reawakening

n Duration 15 min (if the benzodiazepine action is long, the action of the antidote will come to an end after 15 min and the patient goes back to sleep again, monitoring the patient is mandatory till the effect of the benzodiazepine comes to an end!)

n Re-sedation if long acting benzodiazepine is used

n Can precipitate withdrawal reaction in habituated patients



Neuroleptanalgesia rarely used here (don't know if the doctor meant in our hospital or in Jordan in general)

n Major tranquilizers: chlorpromazine, droperidol

And Opiates: Fentanyl, Morphine, Sufentanyl, Alfentanil, Remifentanil, Omnopon® (Morphine, Papaverine , Codeine)

n Many side effects è delay in use

1. Behavioral syndromes:

- Inhibition of purposeful movement

- Inhibition of learned behavior

- Catalepsy: a condition characterized most often by rigidity of the extremities and by decreased sensitivity to pain

2. Alpha adrenergic blockade

3. Hypothermia

4. Extra-pyramidal effects

5. Anti-cholinergic effects

Droperidol we use it in the ICU not in anesthesia!

- Dose: 5 mg I.V

- produce marked catalepsis

- Inner anxiety

- Duration: around 2 hours

*Fentanyl is the most common one

We start to give a small dose then we go up slowly, for example if the patient weighs 70kgs, and we want to sedate him/her, we start with 20mcg and observe the response (it's mixed with benzodiazepine), if the patient wasn't sedated we increase the dose. In this case maximum dose is 70mcg!

- Maximum dose 1mcg/kg, in some cases we might go above that; especially if the procedure took more time.

- Potent Narcotic analgesic

- Potent respiratory depressant

- Duration of action: around 35 min

Now, if the patient goes under respiratory depression, we have to give an antidote which is Naloxone "…is most commonly injected intravenously for fastest action. The drug generally acts within a minute, and its effects may last up to 45 minutes. It can also be administered via intramuscular or subcutaneous injection." Wiki Naloxone Hydrochloride Injection, USP is a sterile, nonpyrogenic solution of Naloxone hydrochloride in water for injection. Each milliliter (mL) contains 0.4 mg Naloxone hydrochloride and sodium chloride to adjust tonicity in water for injection.

So, when sedating patients, doctors need to have two antidotes in case of emergency: Flumazenil(antidote for benzodiazepine) and Naloxone (antidote for opioids); in the emergency trolley.

Nitrous Oxide laughing gas

We don't use it in our hospital, unless there is an I.V access; in case if the patient got spasm.

n Inorganic gas N2O

n A strong Analgesic, WEAK ANESTHETIC!

n High safety margin

n Can be used in concentrations up to 70%; we can mix 70% nitrous oxide and 30% oxygen( the minimal dose of oxygen concentration in general anesthesia is 30% not less)

For example; 1 liter oxygen and 3 liters nitrous oxide …

n Needs special administration machine/anesthesia machine

n Safe in to use in the normal time limits of surgery

n Need a scavenging system; due to pollution

n Use nasal masks with two-way valve outlets



Sedative Anesthetics (intravenous agents)

n *Propofol most commonly used

-ultra-short acting hypnotic agent; if you don't administer a bullous dose of it the patient will awake quickly.

- Rapid clear-headed recovery

- I.V infusion from syringe pump, continuous to keep the patient sedated, when we want to awake the patient we just stop the infusion and the patient wakes up.

- titrate dose to desired response

- can achieve very well controlled sedation.

§ Target-controlled infusions of propofol

§ Patient controlled infusions of propofol successfully tried

§ Very easy to render patient unconscious!!

§ - Should only be given by personnel trained in anesthetic skills:

- Tracheal intubation

- Artificial ventilation

- Cardiovascular resuscitation

Why? Because the propofol can blunt the reflexes we talked about, so if there was even a slight overdose the patient that can have regurgitation, can have aspiration. The doctor recommends to always give Propofol when there is an anesthetist around! (skilled with CPR and airway management)

n Ketamine another intravenous hypnotic agent, main disadvantage: it's associated with hallucinations (especially old people). It was common in World War II; it is a safe drug, no respiratory depression (while other I.V sedatives can cause it).

n Etomidate

n Sodium Thiopental … both rarely used for sedation.



Dexmedetomidine new medication = Precedex

Here the doctor said that this trade name is not required from us (probably he was talking about all trade names mentioned before)

n An alpha2 adrenergic selective agonist

n It has sedative, analgesic, anxiolytic properties and less respiratory depression

n Comparable to propofol with the added advantage of analgesia

n May cause extra sedation and hemodynamic changes, other side effects: bradycardia and hypotension



Risks of Sedation in general

1. Depression of Airway Reflexes

2. Inter-individual variability

3. Interactions with other medications

4. Allergic responses

5. Cardiovascular complications

6. Disinhibition reaction

** Most of the sedatives (all the ones we mentioned) cause hypotension except the Ketamine



We should be prepared:

n Patient checkup:

- A concise medical history and relevant examination and investigation

- General practitioner

n Assessment for potential airway problems

n Informed Consent

n Nil-by-Mouth; the patient should be fasting for at least 6 hours (general anesthesia and sedation) NPO: Nil per os in latin SMOKING IS STOPPED TOO! Why fasting? To avoid aspiration; the patient is sedated and can't protect himself, so if there was any food in his/her stomach, it can get out of it and go into his/ her lungs and aspiration happens. Why stop smoking? The airway tract is covered by celia (smoking will affect it) and those patients have their airway irritable so they are liable for a bronchospasm, another thing is during the recovery phase (especially in general anesthesia) if the patient can't protect his/her airways, some of the secretions will go down, since the celia can't do its job, all the secretions will go down… doctors words smoking is stopped at least 6-8 weeks before the procedure. If it was an emergency and we needed to sedate the patient before that, we ask him/her to stop smoking for at least 24 hours as it will improve the oxygenation of the patient.

- One of the side effects of these medications is nausea and vomiting.(only nauseated when the stomach is empty)



This is a classification important in general anesthesia; sometimes we give the patient the medication but find it difficult to put the endotracheal tube (anatomical problems), this Mallampati classification was put to asses whether we can intubate this patient or not. The patient is asked to open his/her mouth and asked to protrude his/her tongue. As we go from class I to class IV, the intubation becomes more difficult.

Class IV we can only see the hard palate; most difficult to intubate.

Class III we can see the hard palate and part of the uvula(base of the uvula).

Class II we can see the hard palate, soft palate and larger amount of the uvula.

Class I we can see the hard palate, soft palate and the uvula completely; the easiest to intubate.

Surgery Staffing

n A trained assistant:

- Assistance to Dentist

- Monitoring the patient

- Cardiopulmonary resuscitation

Do you need an anesthetist present?

n Possible airway problems

n Very young / very old

n Concurrent medical problem

n Deep sedation

Monitoring same as general anesthesia

n Routine use of pulse oximeter and heart rate.

n Means of blood pressure Monitoring (non-invasive blood pressure)

n Electrocardiogram ( ECG )

n Defibrillator for use in emergency

· End-tidal CO2 is for general anesthesia, while in sedation we don't; there is no tube to connect with.

Emergency drugs that should be available (on Resuscitation trolley)

- Adrenaline… it's important in cardiac arrest.

- Atropine… advanced cardiac arrest and to reverse bradycardia (it's prepared before the procedure and could even lead to tachycardia) vasovagal attack is common in dentistry; it causes bradycardia. A monitor is important to detect it. Dose : 0.1mg/ml

- Dextrose 50%... hypoglycemia.

- Flumazenil… benzodiazepine antidote.

- Lignocaine... to treat arrhythmia. (class II B)

- Naloxone… opioid antidote.

Recovery and Discharge

- Allow patient to recover in a quiet environment

- Patient must be under observation until fully recovered

- Recovery area should be equipped to the same standards as the procedure area

- Discharge patient after review by qualified practitioner

- Written instructions regarding after care

- Avoid alcohol, driving, machinery, signing documents

- In care of a responsible adult

The doctor stopped here, I copied-pasted the rest from the slides



In Europe

n England and Switzerland were the only two countries in Europe where dental procedures under deep sedation or G/A where carried out outside hospitals i.e. in dental clinics.

n This stopped in in England in 1998 after introduction of new guidelines èfollowed by growth in the use of conscious sedation

n Training programs in conscious sedation for dentists - both theoretical and practical - are provided in the public sector and in certain universities . And this includes special emphasis on resuscitation skills as a prerequisite for licensing .

In the States

n ADA è document on “the use of conscious sedation, deep sedation and general anaesthesia in Dentistry”

ADA Educational Guidelines:

* Part one: “Teaching The Comprehensive Control of Pain and Anxiety to the Dental Student” è Conscious sedation

* Part Two: “Teaching The Comprehensive Control of Pain and Anxiety to the dentist at the advanced educational level” è deep sedation / General anesthesia

* Part three: “Teaching The Comprehensive Control of Pain and Anxiety in continuing education program” è conscious sedation

* Completion of ADA accredited post-doctoral training program commensurate with the above document è deep sedation / general anesthesia

Risk Management

n Using only familiar drugs

n Only to correctly indicated patients

n Comprehensive preoperative assessment

n Conducting continuous monitoring

n Appropriate emergency drugs and equipment

n Full documentation

n Utilizing sufficient well trained support personnel

n Treating high risk patients in a well equipped setting for their care
Good Luck everyone (:














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Shadi Jarrar
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عدد المساهمات : 997
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تاريخ التسجيل : 2009-08-28
العمر : 26
الموقع : Amman-Jordan

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