copyright © 2005 by elsevier inc. all rights reserved. anesthesia and pain control chapter 37

Copyright © 2005 by Elsevier Inc. All rights reserved.

Anesthesia and Pain Control

Chapter 37


Anxiety and Pain Control

A technique of various psychological, physical, and chemical approaches to

prevent and treat preoperative, operative, and postoperative anxiety and pain.


Methods of Pain Control

• Anesthetic Agents

• Inhalation Sedation

• Antianxiety Agents

• Intravenous Sedation

• General Anesthesia


Topical Anesthesia

• Provides a temporary numbing effect on nerve endings located on the surface of the oral mucosa.

• Supplied As

– Ointments

– Liquids

– Sprays


Fig. 37-1 Topical anesthetic (Courtesy Premier Dental Products.)


Local Anesthesia• Agent most frequently used for pain control

in dentistry.

• Characteristics

– Be nonirritating to the tissues in the area of the injection

– Produce minimal toxicity

– Be of rapid onset

– Provide profound anesthesia

– Be of sufficient duration

– Be sterile

– Be completely reversible


Method of Action

• Local anesthesia temporarily blocks the normal generation and conduction action of the nerve impulses.

• Local anesthesia is obtained by injecting the anesthetic agent near the nerve in the area intended for dental treatment.

• Induction time is the length of time from the injection of the anesthetic solution to complete and effective conduction blockage.


Duration

• Length of time from induction until the reversal process is complete.

• Short-acting

– Local anesthetic agent lasting 60-180 minutes

• Intermediate-acting


• Long-acting



Vasoconstrictor

• Criteria for Use

– Prolongs the duration of an anesthetic agent by decreasing the blood flow in the immediate area of the injection.

– Decreases bleeding in the area during surgical procedures.

• Types

– Epinephrine

– Levonordefrin

– NeoCobefrin


Ratio of Anesthetic Solution to Vasoconstrictor

• 1:20,000

• 1:50,000

• 1:100,000

• 1:200,000


Contraindications for Vasoconstrictors

• Unstable angina.

• Recent myocardial infarction.

• Recent coronary artery bypass surgery.

• Untreated or uncontrolled severe hypertension.

• Untreated or uncontrolled congestive heart failure.


Injection Techniques

• Infiltration is achieved by injecting the solution directly into the tissue at the site of the dental procedure.

– Most frequently used to anesthetize the maxillary teeth.

– 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.

• Type of injection required for most mandibular teeth.


Fig. 37-4 Maxillary and Mandibular Injection Sites (From Malamed SF: Handbook of Local Anesthesia, ed 5, St. Louis, 2004, Mosby.)


Fig. 37-6 Local Anesthesia Setup


Anesthetic Cartridge• Care and Caution of Use

– Cartridges should be stored at room temperature and protected from direct sunlight

– Never use a cartridge that has been frozen

– Do not use a cartridge if it is cracked, chipped, or damaged in any way

– Never use a solution that is discolored or cloudy or has passed the expiration date

– Do not leave the syringe preloaded with the needle attached for an extended period of time

– Never save a cartridge for reuse


Fig. 37-8 Color-Coding of Local Anesthetic Cartridges (From Malamed SF: Handbook of local anesthesia, ed 5, St. Louis, 2004, Mosby.)


Local Anesthetic Cautions

• Injection into a blood vessel

• Infected area

• Localized toxic reaction

• Systemic toxic reaction

• Temporary numbness

• Paresthesia


Electronic Anesthesia• A noninvasive method to block pain electronically

by using a low current of electricity through contact pads that target a specific electronic waveform directly to the nerve bundle at the root of the tooth.

• Benefits to the Patient

– No needles

– No postoperative numbness or swelling

– Chemical-free method of anesthesia

– No risk of cross-contamination

– Reduces fear and anxiety

– Patients have control over their own comfort level


Inhalation Sedation• Nitrous oxide/oxygen (N²O/O²) is a combination

of gases the patient inhales to help eliminate fear and to help relax the patient.

• History

– Dates back to 1844

– Dr. Horace Wells first used on his patients

• Effects

– Nonaddictive

– Easy onset, minimal side effects, rapid recovery

– Produces stage I anesthesia

– Dulls the perception of pain


Advantage of Using N²O/O²

• Administration is simple and easily managed

• Services of anesthetist or other special personnel not necessary

• Excellent safety record

• Minimal side effects

• Patient awake

• Recovery rapid

• Used with all age of patients


Contraindications of Using N²O/O²

• Pregnancy: First trimester

• Nasal Obstruction: Problems inhaling through the nose

• Emphysema: Increased O²

• Multiple Sclerosis: Breathing difficulties

• Emotional Stability: Altered perception of reality


Inhalation Sedation Equipment

• Cylinders: Gases are dispensed from steel cylinders, which are colored green for O² and blue for N²O.

• N²O machines: Portable or part of the dental unit.

– Control valves: Control the flow of each gas.

– Flowmeter: Indicates the rate of flow of the gases.

– Reservoir bag: The two gases are combined in this bag and the patient draws on it for breathing.


Inhalation Sedation Equipment-cont’d

• Gas hose

– Carries the gases from the reservoir bag to the mask or nosepiece.

• Masks: Supplied in sizes for adults and children

– The nosepiece through which the patient breathes the gases.

• Scavenger system

– Protection from the occupational risks of N²O.


Fig. 37-10 Portable Nitrous Oxide System Unit


Exposure to Nitrous Oxide

• Used only for patient treatment.

• Never administered for recreational purposes.

• 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.


Fig. 37-13 Scavenger system


Patient Preparation for Inhalation Sedation

• Review health history.

• Obtain base-line vital signs.

• Describe the procedure of administering the gases.

• Describe the use of the mask and the importance of nasal breathing.

• Describe the sensations that the patient will experience.

• Reassure the patient.


Assisting in the Administration of Inhalation Sedation

• Start 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.


Antianxiety Agents

• Sedatives are the drug of choice by physicians and dentists for relief of anxiety.

• Criteria for Use

– Patients are very nervous about a procedure.

– Procedures are long or difficult.

– Mentally challenged patients.

– Very young children requiring extensive treatment.


Commonly Prescribed Sedatives

• Secobarbital sodium (Seconal)

• Chlordiazepoxide HCl (Librium)

• Diazepam (Valium)

• Chloral hydrate (Noctec): For children


Intravenous Sedation

Antianxiety drugs administered intravenously throughout a procedure at a slower pace,

providing a deeper stage I analgesia.


Intravenous Sedation-cont’d

• Patient Assessment

– A health history, physical examination, and signed consent are performed.

– Baseline vital signs are taken and recorded.

– Oximetry and electrocardiogram are completed and recorded.

– Weight taken and recorded for dose determination.


Intravenous Sedation-cont’d

• Patient Monitoring

• Physiologic measurements taken and recorded every 15 minutes.

– Level of consciousness

– Respiratory function

– Oximetry

– Blood pressure

– Heart rate

– 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.

This controlled state loss of consciousness, produces stage III general anesthesia.


General Anesthesia-cont’d

• Pharmacologic Make-up

– Combination of gases

– N²O/O²

– Halothane or enflurane mixtures

– Intravenous agents such as thiopental sodium and methohexital sodium


Four Stages of Anesthesia• Stage I: Analgesia

– The stage at which a patient is relaxed and fully conscious.

– Able to keep his or her mouth open without assistance and is capable of following directions.

– Have a sense of euphoria and a reduction in pain.

– Vital signs are normal.

– The patient can move into different levels of analgesia.


Four Stages of Anesthesia-cont’d

• Stage II: Excitement

– The stage at which a patient is less aware

of his or her immediate surroundings

– Starts to become unconscious

– The patient can become excited and unmanageable

– Nausea and vomiting can occur

– This is an undesirable stage



• Stage III: General Anesthesia

– The stage of anesthesia that begins when the patient becomes calm after stage II

– 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

– The stage at which the lungs and heart slow down or stop functioning

– If this stage is not reversed quickly, the patient will die


General Anesthesia-cont’d• Patient Preparation

– Preoperative physical examination.

– Laboratory tests.

– Patient or legal guardian must sign a consent form.

• Preoperative Instructions

– Dentist will review the procedure, as well as the risks.

– Must not have anything to drink or eat 8 to 12 hours before receiving general anesthesia.


Record Keeping for Sedation Methods• Always document the following measures

and observations:

– Review of patient’s medical history.

– Preoperative and postoperative vital signs.

– Patient’s tidal volume if using inhalation sedation.

– Time anesthesia began and ended.

– Peak concentration administered.

– Amount of postoperative time (in minutes) for patient recovery.

– Adverse events or patient complaints.

copyright © 2005 by elsevier inc. all rights reserved. anesthesia and pain control chapter 37

Documents

minutes slide

local anesthetic agent

local anesthesia agent

reversible slide

topical anesthesia

block anesthesia

profound anesthesia

ratio of anesthetic