Chapter 37 – Anesthesia and Pain Control
Methods of Pain Control
Anesthetic Agents Intravenous (IV) Sedation
Inhalation Sedation General Anesthesia
Antianxiety Agents
Topical Anesthesia
Provides a temporary numbing effect on nerve endings located on the surface of the oral mucosa.
Placed on mucosa for 3-5 minutes
Supplied as: Ointments, Liquids, Sprays
Local Anesthesia
The agent most frequently used for pain control in dentistry
Characteristics/advantages
o Is nonirritating to the tissues in the area o Delivers profound anesthesia
of the injection o Duration of action is sufficient
o Is minimally toxic o Sterile
o Rapid on onset o Completely reversible
Local Anesthesia Mechanism of Action
Temporary blocks the normal generation and conduction action of the nerve impulses
Obtained by injecting the anesthetic agent near the nerve in the area intended for dental treatment
Induction time:
o Length of time from the injection of the anesthetic solution to complete and effective conduction blockage
Duration
Time from induction to completion of the reversal process
Short acting:
o Local anesthetic agent lasting 60 to 180 minutes
Intermediate:
o Local anesthetic agent lasting 120 to 240 minutes
Long Acting:
o Local anesthetic agent lasting 240 to 540 minutes
Vasoconstrictors – *Prolongs or lengthens the duration of an anesthetic
Indication for use:
o Prolongs the duration of an anesthetic agent by decreasing the blood flow in the immediate area of the
injection.
o Decreases bleeding in the area during surgical procedures
Types:
o Epinephrine – most common
o Levonordefrin
o Neo-Cobefrin
Ratio of Anesthetic Solution to Vasoconstrictor
1:20,000 1:100,000
1:50,000 1:200,000
Contraindications to the Use of Vasoconstrictors
Unstable angina Untreated or uncontrolled severe hypertension
Recent myocardial infarction Untreated or uncontrolled congestive heart
Recent coronary artery bypass surgery failure.
Injection Techniques
Infiltration is achieved by injecting the solution directly into the tissue at the sit of the dental procedure.
o most frequently used to anesthetize the maxillary teeth
o Used as a secondary injection to block gingival tissues surrounding the mandibular teeth
Block anesthesia is achieved by injecting near a major nerve, with the entire area served by that nerve being numbed.
o Type of injection required for most mandibular teeth
Anesthetic Cartridge
Precautions:
o Cartridges should be stored at room temp. and protected from
direct sunlight.
o Never use a cartridge that has been frozen
o Do not use a cartridge if it is cracked, chipped, or damaged in any way.
o Never use a solution that is discolored or cloudy or has passed the expiration date.
o Do not leave the syringe preloaded with the needle attached for an extended period.
o Never save a cartridge for reuse.\
Needle
Gauge (lumen size):
o Thickness or size of the needle o Small number=thicker needle
o Larger number=thinner needle
Length:
o Short: 1 inch o Long: 1 5/8 inch
Local Anesthetic Cautions
Injection into a blood vessel Systemic toxic reaction
Infected area Temporary numbness
Localize toxic reaction Paresthesia
Chapter 37
Inhalation Sedation
Nitrous oxide/oxygen is a combination of gases inhaled to help eliminate fear and aid relaxation
History:
o The use of nitrous oxide dates to 1844
o Dr. Horace Wells was the first to use nitrous oxide on patients
Effects:
o Nitrous oxide/oxygen is non additive
o Onset is easy, side effects are minimal, and recovery is rapid
o Nitrous oxide/oxygen produces stage I anesthesia
o Nitrous oxide/oxygen dulls the perception of pain
Advantage of Using N2O/O2
Administration is simple and easily managed Side effects are minimal
The services of anesthetist or other special The patient is awake
personnel are not required Recovery is rapid
N20/02 has an excellent safety record N2O/O2 can be used with patients of all ages
Contraindications to Use of N2O/O2
Pregnancy: first trimester Emphysema: increase O2
Nasal obstruction: problems inhaling through the Multiple sclerosis: breathing difficulties
nose Emotional stability: altered perception of reality
Inhalation Sedation Equipment
Cylinders:
o Gases are dispensed from steel cylinders, which are colored green for O2 and blue for N2O
N2O machines are portable or part of the dental unit:
o Control valves control the flow of each gas
o A flowmeter indicates the rate of flow of the gases
o The two gases are combined in a reservoir bag, which the patient draws on for breathing
Gas hose:
o Carries the gases from the reservoir bag to the mask or nose piece
Masks: supplied in sizes for adults and children
o The nose piece through which the patient breathes the gases
Scavenger system:
o Protection from the occupational risks of N2O
Exposure to Nitrous Oxide
Used only for patient treatment
Never administer for recreational purposes
How to reduce N2O hazards to dental personnel:
o Use a scavenger system
o Use a patient mask that fits well
o Discourage the patient from talking
o Vent gas outside the building
o Routinely inspect equipment and hoses for leaks
o Use a monitoring-badge system to detect N2O
Patient Preparation for Inhalation Sedation
Review the patients’ health history Describe the use of the mask and the importance
Obtain baseline vital signs of basal breathing
Describe the procedure of administering the gases Describe the sensations that the patient will
experience
Reassure the patient
Assisting in the Administration of Inhalation Sedation
Start with pure oxygen
Slowly adjust the nitrous oxide until the desired results are achieved
The patient 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 with the preoperative recordings
Antianxiety Agents
Sedative is the drug of choice for physicians and dentists seeking the relieve anxiety in their patients
Criteria for use:
o A patient is very nervous about a procedure
o A procedure is long or difficult
o The patient is mentally challenged
o The patient is a very young child requiring extensive treatment
Commonly Prescribed Sedatives
Secobarbital sodium (Seconal) Diazepam (valium)
Chlordiazepoxide Hydrochloride (Librium) Chloral Hydrate (Noctec): for children
IV Sedation
Antianxiety drugs administered IV throughout a procedure at a slower pace, providing a deeper stage I analgesia.
Patient assessment:
o A health history is taken, a physical examination performed, and signed consent obtained.
o Baseline vital signs are taken and recorded.
o Oximetry and electrocardiography are performed, and signed consent obtained
o The patient’s weight is taken and recorded for the determination of dosage
Patient Monitoring
Physiologic measurements are recorded every 15 minutes:
o Level or consciousness
o Respiratory function
o Oximetry
o Blood Pressure
o Heart Rate
o Cardiac Rhythm
General Anesthesia
A controlled state of unconsciousness with a loss of protective reflexes- including the ability to maintain an airway
independently and to respond appropriately to physical stimulation or verbal command-that produces stage III general
anesthesia.
Four Stages of Anesthesia
Stage I: analgesia
o At this stage the patient is relaxed and fully conscious
o The patient is able to keep his or her mouth open without assistance and is capable of following directions.
o The patient has a sense of euphoria and a reduction in pain
o Vital signs are normal
o The patient can move into different levels of analgesia
Stage II: excitement
o At this stage the patient is less aware of his or her immediate surroundings
o The patient may become excited and unmanageable
o Nausea and vomiting may occur
o This is an undesirable stage
Stage III: general anesthesia
o This stage of anesthesia begins when the patient becomes calm after stage II
o The patient feels no pain or sensation
o The patient will become unconscious
o 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
o At this stage the lungs and heart slow down or stop functioning.
o If this stage is not reversed quickly, the patient will die
General Anesthesia
Patient preparation
o Preoperative physical exam
o Lab tests
o Signature of patient or legal guardian on a consent form
Preoperative instructions
o The dentist will review the procedure, as well as the risks
o The patient must not have anything to drink or eat 8 to 12 hours before undergoing general anesthesia
Recordkeeping for Sedation Methods
Always document the following measures and observations:
o Review of the patient’s medical history
o Preoperative and postoperative vital signs
o Patient tidal volume in inhalation sedation is being used
o Times at which anesthesia began and ended
o Peak concentration administered
o Postoperative time (in minutes) required for patient recovery
o Adverse events and patient complaints
