Sedation and general anesthesia in dentistry

transcript

Sedation and General Anesthesia in Dentistry

Assistant professor : Akram Thabet NasherB.D.S, M.Sc. , Ph.D.

Head department of oral and maxillofacial surgeryFaculty of Dentistry- Sana`a university

Anesthesia

The practice of various psychological,

physical, and chemical approaches to the

prevention and treatment of preoperative,

operative, and postoperative anxiety and

Sedation and General Anesthesia Dr.Akram Thabet

Levels of Anesthesia

Local anesthesia

Conscious Sedation

Deep Sedation

General Anesthesia

Local Anesthesia

Local, or regional, anesthesia involves the

injection or application of an anesthetic

drug to a specific area of the body. It

eliminates sensation and pain in a local

area of the body without loss of

consciousness. Sedation and General Anesthesia Dr.Akram Thabet

According to the degree of CNS depression:

◦Conscious Sedation

◦Deep Sedation

◦General Anesthesia

Sedation

It is a technique where one or more drugs

are used to depress the Central Nervous

System of a patient thus reducing the

awareness of the patient to his surrounding.

Conscious Sedation It is a controlled, pharmacologically

Induced, minimally depressed level of

consciousness that retains the patient’s

ability to maintain a patent airway

independently and continuously and

respond appropriately to physical and/or

verbal command. ventilatory and cardiovascular functions are

unaffected Sedation and General Anesthesia Dr.Akram Thabet

Deep Sedation

It is a controlled, pharmacologically induced state of

depressed level of consciousness , from which the

patient is not easily aroused and which may be

accompanied by a partial loss of protective reflexes,

including the ability to maintain a patent airway

independently and/or respond purposefully to

physical stimulation or verbal commands.

General Anesthesia

The elimination of all sensations

accompanied by the loss of consciousness.

Sometimes, the two phrases (GA & Deep

Sedation) refer to one physiologic

state.Sedation and General Anesthesia Dr.Akram Thabet

Risks of Anesthesia

N20Anxiolysis

LocalAnesthesia

ConsciousSedation

DeepSedation

GeneralAnesthesia

Fundamental Concepts: It is easy to drift from one state to another.

Any anesthetic/sedative/opioid regardless of route of administration can be a general anesthetic (can cause unconsciousness)

Patient state is considered in terms of the level of consciousness rather than the technique involved.

Sedation techniques are not pain-control techniques.

Indications:1- Behaviorally challenged patients (stressful and fearful patients).

2- Young children

3- Mentally retarded Patients

4- Major operations in oral and maxillofacial surgery

5- Stressful Procedure ( multiple 3 rd Molar extractions, Interosseous implants ,complex periodontal surgery)

6- Gagging reflexes

7- Local Anesthesia problems

8- Medically compromised patients

Routes of Administration: Enteral – any technique of administration in which the agent is

absorbed through the gastrointestinal (GI) tract or oral mucosa [i.e., oral, rectal, sublingual].

Parenteral – a technique of administration in which the drug bypasses the gastrointestinal (GI) tract [i.e., intramuscular (IM), intravenous (IV), intranasal (IN), submucosal (SM), subcutaneous (SC), intraosseous (IO)].

Transdermal – a technique of administration in which the drug is administered by patch or iontophoresis through skin.

Transmucosal – a technique of administration in which the drug is administered across mucosa such as intranasal, sublingual, or rectal.

Inhalation – a technique of administration in which a gaseous or volatile agent is introduced into the lungs and whose primary effect is due to absorption through the gas/blood interface.

Sedation

Anxiolysis

Interactive

Arousable

Airway is maintained

Protective reflexes are intact

Responses to command are intact

Sleeplike state

Non-Interactive

Non- arousable(except with tense stimulation)

Inability to maintain airway

Partial loss of reflexes

Difficult to respond to command

Cons. Sedation Deep Sedation Minimally Depressed Consciousness Deeply depressed consciousness

Sedation techniques Non - titrable Technique

Oral SedationRectal SedationIntramuscular SedationSubmucosal SedationIntranasal Sedation

Titrable TechniqueInhalational SedationIntravenous Sedation

Combination Of the two Sedation and General Anesthesia Dr.Akram Thabet

I- Oral Sedation By far, it is the most universally accepted and

easiest method of sedation administration.

The most variable (non-titrable) technique

Recovery time prolonged

Difficult to reverse unwanted effect

Utilizing escort

No repeated doses

Advantages of Oral SedationUniversal acceptabilityEase of administrationLow costIncidence of adverse reactions less than

some other techniquesNo needles, syringes or special techniquesVarious drugs, dosage forms availableAllergic reactions less severe than seen in

parenteral administration No specialized training

Disadvantages of oral Route Reliance on patient cooperation

Prolonged onset

Erratic absorption, unpredictable effect

Inability to titrate to effect

Inability to readily lighten or deepen

Prolonged duration of effect

Adverse interactions of sedative drugsSedation and General Anesthesia Dr.Akram Thabet

Contraindications to oral SedationSevere dental anxiety & fear

High probability of adverse drug interaction

Poor past experience with oral sedation

Allergy to drug being used

Other drug contraindications (pregnancy ,

glaucoma, etc.)

Need for rapid onset and/or rapid recovery

Factors Influencing Oral Drug AbsorptionLipid solubilitypH of gastric tissuesMucosal surface areaGastric emptying timeDosage form of drugDrug inactivation (“first pass effect”)Presence of food in stomachBioavailability of drugGenetics

II- Inhalational SedationNitrous oxide/oxygen inhalation sedation is

the most commonly used technique in dentistry for sedation .

Nitrous oxide/oxygen (N²O/O²) sedation is a combination of these gases that the patient inhales to help eliminate fear and to help the patient relax.

Equipments

Continuous flow design

with flow meters

Safe delivery of O2 and

Pin-indexed yoke system

Efficient scavenger

Nasal Mask

Advantages of Nitrous OxideRapid onset (almost equal to that of IV. administration ) Ability to titrate & to reverseDepth of sedation readily alteredFlexible duration of action Rapid recovery from sedationSafeNo injection requiredVery few side effectsNo adverse effects on vital organsPatient can be discharged aloneNon addictive.Produces stage I anesthesia. Dulls the perception of pain. Sedation and General Anesthesia

Dr.Akram Thabet

Disadvantages of Nitrous Oxide

Initial cost of cumbersome equipment is high

Continuing costs of gases high

Equipment takes up operatory space

Requires constant patient cooperation

Chronic exposure of office personnel can cause

Carcinogenicity , Teratogenicity or Toxicity

Not always effectiveSedation and General Anesthesia Dr.Akram Thabet

Relative Contraindications to Inhalation Sedation:

Severe dental anxiety & fearCompulsive personalitiesPoor past experience with oral sedationPregnancyURI, COPDNasal obstruction: Problems inhaling through the

noseEmphysema: Increased O²

Multiple sclerosis: Breathing difficultiesEmotional stability: Altered perception of reality

Potential Problems Diffusion hypoxia

Vomiting

Toxicity: inhibit vitamin B12 dependent enzymes (Pernicious anemia)

Reproductive Abnormalities

Administration of Inhalation sedationStart with pure oxygen while establishing the

patient’s tidal volume.Slowly titrate the nitrous oxide until the desired

results are achieved. Patients should refrain from talking or mouth

breathing. The N²O/O² analgesia should end with the

administration of 100% O² for 3 to 5 minutes. Obtain postoperative vital signs and compare

them to the preoperative recordings.

How to reduce N²O hazards to dental personnel ??

◦Use a scavenger system. ◦Use a patient mask that fits well.◦Discourage patients from talking. ◦Vent gas outside the building. ◦Routinely inspect equipment and hoses

for leaks. ◦Use an N²O monitoring badge system.

III- Intravenous SedationAntianxiety drugs that are administered

intravenously continuously throughout the procedure at a slower rate, providing a deeper stage I analgesia.

The most rapid technique; onset is approximately 20 to 25 seconds.

In children under 6 years, the incidence of untoward effects is increased

Drugs for sedations :

Either one drug or combinations of IV drugs

Commonest combinationsBenzodiazepines & opioidsPropofol & opioids

Valium (Diazepam)BenzodiazepineProduces sleepiness and relief of apprehensionOnset of action 1-5 minutesHalf-life

◦ 30 hours◦ Active metabolites

Average sedative dose◦ 10-12 mg

Versed (Midazolam)Short acting benzodiazepine

◦ 4 times more potent than ValiumProduces sleepiness and relief of apprehensionOnset of action 3-5 minutesHalf-life

◦ 1.2-12.3 hoursAverage sedative dose

◦ 2.5-7.5 mg

Demerol (Meperidine)NarcoticPain attenuation and some sedationOnset of action

◦3-5 minutesHalf-life

◦30-45 minutesAverage dose

◦20-50 mg

Fentanyl (Sublimaze)Narcotic/Opiod agonist

◦100 times more potent than MorphinePain attenuation and some sedationOnset of action around 1 minuteHalf-life

◦30-60 minutesAverage dose

◦0.05 – 0.06 mg

Additional MedicationsLikely to be seen in scenarios where

deeper levels of sedation are being performed◦Propofol (Diprivan)◦Robinul (Glycopyrrolate)

Propofol (Diprivan)Intravenous anesthetic/sedative hypnoticSedative, anesthetic and some antiemetic

propertiesOnset of action within 30 secondsHalf-life

◦2-4 minutesAverage sedative dose

◦Varies

Robinul (Glycopyrrolate)Anticholinergic

◦Heart rate increases◦Salivary secretions decrease

Dose 0.1-0.2 mgOnset of action within 1 minute

General anesthesia

Stages of General AnesthesiaStage I “Conscious Sedation”

◦AnalgesiaStage II

◦DeliriumStage III (“Deep Sedation/General Anesthesia)◦Surgical anesthesia

Stage IV◦Medullary paralysis

Four Stages of Anesthesia:Stage I: Analgesia is the stage at which a

patient is relaxed and fully conscious. The patient is able to keep his or her mouth open without assistance and is capable of following directions. The patient will have a sense of euphoria and a reduction in pain. Vital signs are normal. Depending on the agent used, the patient can move into different levels of analgesia.

Stage II: Excitement is the stage at which a patient is less aware of his or her immediate surroundings and can start to become unconscious. The patient can become excited and unmanageable. Nausea and vomiting can occur. This is an undesirable stage.

Stage III: This stage of General anesthesia in which the patient becomes calm after stage II. This is the favorable stage for doing surgery. The patient feels no pain or sensation. The patient will become unconscious. This stage of anesthesia can be met only under the guidance of an anesthesiologist in a controlled environment such as a hospital.

Stage IV: Respiratory failure or cardiac arrest is the stage at which the lungs and heart slow down or stop functioning. If this stage is not reversed quickly, the patient will die.

Intubation in GA. For maintenance of respiration :

Types of General AnestheticsInduction agents( begins the anesthesia)

◦ Induction agents usually administered IV ◦can be inhalational for those who do not

tolerate IV access

Maintenance agents (maintain the anaestheisa)◦Maintenance agents usually administered

inhalationally or IV with bolus or continuous infusion technique

Routes for Delivery of General Anesthetics

Intravenous (IV)

Inhalational

Structural formulas of anesthetic drugs.Sedation and General Anesthesia Dr.Akram Thabet

General Anesthetics-Intravenous Agents

Primary role as induction agents Maintenance with total intravenous anesthesia

◦ Rapid redistribution◦ Shorter half lives◦ Environmental risk of inhalational agents

Rapid distribution to vessel rich tissues High lipid solubility allows for rapid induction When redistributed out of the brain, the effect decreases Advantages

◦ Rapid and complete induction◦ Less CV depression

General Anesthetics-Intravenous Agents

The most commonly drugs used in GA:1- Benzodiazepines2- Opioids3- Ketamine4- Methohexital5- Propofol

General Anesthetics-Inhalational Agents

1- Nitrous Oxide2- Sevoflurane3- Desflurane4- Isoflurane (Forane)5- Halothane

Technician Responsibilities

Pre anesthetic Evaluation‐

“Never treat a stranger”

Never do anesthesia on a patient you have

not previously evaluated.

Never sedate or aesthesis

on first patient visit

Always have a consultation first!

Pre anesthetic Examination‐

Physical examination Evaluation of anxiety level Review of medical history Review medications and drug allergies Assign ASA classification Review prior sedation / anesthetic history Obtain informed consent Give pre sedation/ anesthesia instructions‐

Medical historyDiseases to evaluate: HTN;, asthma, COPD, URI, DMPregnancy; psychiatric renal; hepatic problems Obesity; sleep apnea; etc Medications Prior anesthetic experience Allergies Hospitalizations

Physical Examination Vital signs Appearance Height, Weight, & BMI (Body Mass Index) Mental & psychological status Cardiac & pulmonary level ;Exercise tolerance (“if they can walk up 2

flights of stairs to your office, they’re probably ok for anesthesia”)

Airway evaluationSedation and General Anesthesia Dr.Akram Thabet

Airway Evaluation BMI (Body Mass Index)History of obstructive sleep apnea, snoring Mallampati scoreProtrusive (ask: “bite your upper lip with your

lower teeth”) TMJ range of motion (oral opening) Neck circumference

Airway patency

ASA Physical Classification IA normal healthy patient

II A patient with mild systemic disease

III A patient with severe systemic

IVA patient with severe systemic

disease that is a constant threat to life

VA moribund patient who is not expected

to survive without the operationSedation and General Anesthesia Dr.Akram Thabet

Pre-Procedure Patient Assessment◦ Investigations :◦ECG, echo ◦Chest – x-ray◦CBC◦BT,CT ,PT T, PT ,INR◦Na , k◦R.B.S or F.B.S◦LFT◦KFT ◦HBs-Ag◦HIV Sedation and General Anesthesia

Dr.Akram Thabet

Medical Consultations

After doing the medical and physical

examination with the full investigations; the

patient should be evaluated by a medical

doctor or anesthetist to do a medical

fitness for him to receive the anesthesia.

Informed Consent It’s a process, not a piece of paper.Verbal and written informed consent must be given at the

pre op consultation appointment, not the day of surgery‐Cannot be obtained once medications are administered.New written consent must be obtained for each procedure

or sedation.Consent to surgery does not imply consent for sedation;

sedation needs to be specified.Consent must be obtained by the doctor in face to face ‐ ‐

meeting, not a staff member.

Pre Sedation/anesthetic Instructions‐

Give both verbally and in writing

Fasting (“NPO”) instructions (if needed) “Vested” escort to accompany patient Patient’s other medications

Pre Procedure Fasting (“NPO”)‐

The patient must be fasted minimum 2-3

hours for clear liquids and 6 hours for

solid food to prevent vomiting causing

Suffocation and aspiration pneumonia.

Psychological preparation Psychological preparation of the patient for the sedation or

GA is paramount.

Explain the different types of sedation available and GA

techniques

Tell them they will be “relaxed, drowsy, comfortable,” and

“aware and in control.”

Give realistic expectations to patient and explain that every

patient reacts differently, and they may need more / less

medication or different technique at future appointments. Sedation and General Anesthesia Dr.Akram Thabet

Intraoperative Responsibilities ◦ Informed consent signed prior to sedation◦ Name, dose, route and time of all medications

documented◦ Procedure begin and end times◦ Prior adverse reactions◦ Pre-medication time and effect◦ Vital Signs

BP Heart Rate Respiratory Rate Oxygen Saturation Level of Consciousness

Monitoring

Level Of ConsciousnessClinical ObservationPulse OximetryPericardial/pretracheal StethoscopeBPECGMonitoring oxygenation

RecoveryPatients may continue to be at significant risk of

developing complications after procedure is completed.

Decreased procedural stimulation, delayed drug absorption, and slow drug elimination, may contribute to residual anesthesia or sedation and respiratory depression during the recovery period.

Patient must be kept in office under observation until completely recovered.

Post-operative Responsibilities ◦Vital Signs at least every 5 minutes

BP Heart Rate Respiratory Rate Oxygen Saturation Level of Consciousness

Sedated/ Anesthetized patients must be continuously monitored until discharged

Recommended Alarm Limits

Low High

Systolic BP 85150

Diastolic BP 50100

Oxygen Saturation 92100

Respiratory Rate 10 16

Heart Rate 60 90

Medical Emergency

SyncopeHypoglycemiaHypotensionHypertensionBronchospasm

LaryngospasmApneaMyocardial infarctionStroke

Medical Emergency

Know how to prevent, recognize, and treat

syncope (fainting)

◦Supplemental O2

◦Elevation of lower extremities

◦Trendelenburg

Be prepared to assist in airway management

Emergency DrugsFlumazenil (Romazicon)Naloxone (Narcan)Esmolol (Brevibloc)EphedrineEpinephrineAtropine

Flumazenil (Romazicon)Benzodiazepine antagonist

◦Versed reversal agentInitial dose – 0.2mg

◦May repeat at 1 minute intervals to dose of 1mg

Onset of action within 1-2 minutesMust monitor for re-sedation

◦May be repeated at 20 minute intervals as needed

Naloxone (Narcan)

Narcotic antagonist

◦Fentanyl reversal agent

Initial dose – 0.4mg

◦May repeat every 2-3 minutes at doses of

0.4-2mg

Monitor for re-sedation

Esmolol (Brevibloc)

Antihypertensive

Beta blocker

Initial dose 0.25 –1.0 mg/kg over 30

seconds

◦Short half-life of approximately 10 minutes

Ephedrine

Used for hypotension

Sympathomimetic

Initial dose 5-10mg

Action may not be seen for several

minutes

Atropine

Significant bradycardia

◦Slow heart beat or NO heartbeat

Anticholinergic

Initial dose 0.25 – 1.0 mg

◦May repeat every 3-5 minutes

◦Maximum total dose .03 mg/kg

Epinephrine

True emergency medication

Administration should be preceded by

activation of the emergency response

system

Discharge CriteriaVital signs normal (within 20% baseline) Airway patency uncompromised Patient awake, or awake on command Can breathe deeply Protective reflexes intact (can cough on command) Adequate hydration, able to drink Patient can speak normally Patient can sit unaided Patient can walk with minimal assistanceResponsible, “vested,” adult escort is availableNo pain, no nausea or vomiting,

Post sedation Instructions‐Verbal and written instructions must be given to

the escort upon discharge from the officeShould include:– Potential and anticipated post sedation effects‐–Limitation of activity (driving, machinery) x 24 hrs– Dietary precautions and suggestions– No other sedatives x 24 hrs– 24 hour contact number for practitioner

Thank You

Sedation and general anesthesia in dentistry

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