Anesthesia and Pain Control – Chapter 37 Flashcards

Introduction

• Anxiety & pain control encompasses psychological, physical, and chemical approaches that prevent or treat pre-operative, operative, and post-operative fear and discomfort.

• Anesthesia = temporary loss of feeling/sensation.

• Anesthetics = drugs that induce this temporary loss.

Methods of Pain Control Mentioned

• Topical anesthesia

• Local anesthesia

• Inhalation sedation (Nitrous Oxide/Oxygen)

• Antianxiety (sedative) agents

• Intravenous (IV) sedation

• General anesthesia

• Mind-body medicine

Topical Anesthesia

• Produces a temporary numbing effect on nerve endings of superficial oral mucosa.

• Supplied as:

  • Ointments

  • Liquids

  • Sprays

  • Patches

Local Anesthesia

• Most frequently used pain-control modality in dentistry; safe, effective, and dependable for nearly all procedures.

Desired Characteristics

• Non-irritating to tissues

• Minimal toxicity

• Rapid onset

• Capable of profound anesthesia of adequate duration

• Completely reversible

• Sterile or heat-sterilizable without deterioration

Chemical Composition

• Two chemical families:

  • Ester-type (mainly used topically)

  • Amide-type (metabolized by liver)

• Each glass cartridge contains:

  • Local anesthetic drug

  • Sodium chloride (for isotonicity)

  • Distilled water (vehicle)

Mechanism of Action

• Temporarily blocks generation & conduction of nerve impulses by bathing the nerve near treatment area.

• \text{Induction time} = interval from injection to full conduction blockade.

Time Span Classifications

• Short-acting ≈ 30 min

• Intermediate ≈ 60 min

• Long-acting ≈ 90 min

Vasoconstrictors

• Purposes

  • ↓ local blood flow → prolong anesthetic duration

  • ↓ bleeding during surgery

• Common agents: Epinephrine, Levonordefrin, Neo-Cobefrin

• Contraindications

  • Unstable angina

  • Recent myocardial infarction

  • Recent coronary artery bypass graft (CABG)

  • Untreated/uncontrolled severe hypertension

  • Untreated/uncontrolled congestive heart failure

Injection Techniques (placement dictated by tooth/nerve anatomy)

• Maxillary infiltration

• Palatal block

• Mandibular block (Inferior alveolar, etc.)

• Periodontal ligament injection

Clinical Setup & Armamentarium

• Aspirating anesthetic syringe

• Pre-filled anesthetic cartridges

• Single-use sterile needle

Handling Guidelines for Cartridges

• Store at room temperature; avoid direct sunlight.

• Never use frozen, cracked, chipped, discolored/cloudy, or out-of-date cartridges.

• Do not leave syringe pre-loaded with needle attached for extended periods; never reuse cartridges.

Disposable Needle Anatomy

• Two-part plastic shield

  • Cartridge end (shorter)

  • Injection end (protected by guard)

• Components: Needle hub, lumen, gauge (thickness)

Complications & Precautions

• Intravascular injection

• Injection into infected tissue (↓ efficacy, ↑ spread)

• Toxic reactions

  • Localized or systemic

• Temporary numbness / soft-tissue injury

• Paresthesia (prolonged or permanent numbness)

Alternative Delivery Systems

• Electronic anesthesia

• Jet-injection (needle-free) devices

• Computer-controlled local anesthetic delivery (CCLAD)

Sedation & General Anesthesia (Lesson 37.2) – Stated Learning Objectives

• Describe inhalation sedation mechanics, equipment, preparation, patient education, dental-assistant role, and safety practices.

• Summarize indications for antianxiety drugs.

• Discuss IV sedation uses in dentistry.

• Discuss general anesthesia, its stages, and resulting consciousness levels.

• Explain mind-body medicine application.

• Emphasize documentation of all anesthesia/pain-control modalities.

Inhalation Sedation – Nitrous Oxide/Oxygen (N2O/O2)

• Mix of gases inhaled for anxiolysis & mild analgesia; produces Stage I anesthesia.

• Non-addictive, rapid onset, minimal side effects, fast recovery; dulls pain perception.

Advantages

• Simple to administer/manage; no anesthetist needed

• Excellent safety record across all ages

• Patient remains conscious & responsive

• Quick recovery → drive home possible (per local regs)

Disadvantages / Side Effects

• Possible nausea, vertigo

• Behaviorally challenged patients may act out

Medical Contraindications / Precautions

• COPD (alters respiratory drive)

• Significant cardiac disease (↑ arterial pressure)

• Pregnancy—especially 1st trimester

• Upper respiratory infection (nasal obstruction)

• Psychiatric disorders / drug dependency (hallucination risk)

• Middle-ear disturbances (pressure changes)

• Critically ill/B
  diff b12-deficient patients (long exposures linked to B12 deficiency, anemia)

Equipment Components

• Cylinders: Green = O2, Blue = N2O

• Control valves regulate individual gas flow

• Flow meter indicates combined flow rate (liters/min) and total \text{tidal volume}

• Reservoir bag mixes gases; patient draws from it

• Gas hose conveys mixture to nasal mask

• Masks available in adult & child sizes (must seal around nose)

Patient Assessment & Monitoring

• Thorough medical history review (drug interactions, contraindications)

• Vital signs (BP, pulse, respiration) recorded:

  • Preoperative (baseline)

  • Periodically during procedure

  • Postoperative (confirm recovery / ID adverse events)

Patient Education Prior to Delivery

• Explain step-by-step procedure; emphasize nasal breathing

• Describe expected sensations (lightheadedness, tingling, warmth)

• Reassure and set expectations for cooperation (no talking, breathe through nose)

Administration Protocol

1. Begin with 100\% oxygen to establish patient’s tidal volume.

2. Gradually titrate N_2O upward until desired sedation is reached (incremental 0.5–1 L/min changes).

3. Maintain verbal contact; adjust flow as needed.

4. Terminate sedation with 100\% oxygen for 3{-}5 min to flush lungs & prevent diffusion hypoxia.

5. Re-record postoperative vitals; compare with baseline.

Safety Work Practices for Staff

• Use N_2O strictly for patient treatment (never recreationally).

• Engineering & administrative controls:

  • Scavenger system attached to mask

  • Well-fitting nasal mask (minimize leaks)

  • Discourage patient from speaking (reduces gas escape)

  • Vent waste gas outside building

  • Regularly inspect equipment/hoses for leaks

  • Utilize personal dosimetry badges for N_2O exposure monitoring

Antianxiety (Sedative) Agents – Oral / Enteral

• Indications:

  • Highly nervous patient

  • Lengthy/complex procedures

  • Mentally challenged individuals

  • Very young children needing extensive work

• Provide conscious sedation; patient maintains protective reflexes.

Intravenous (IV) Sedation

• Antianxiety drugs administered via IV drip or bolus; deeper Stage I analgesia than inhalational.

• Continuous physiologic monitoring (every 15 min):

  • Consciousness level

  • Respiratory rate & function

  • Pulse oximetry \mathrm{SpO_2}

  • Blood pressure

  • Heart rate

  • Cardiac rhythm (ECG)

General Anesthesia

• Controlled state of unconsciousness (Stage III) with loss of protective reflexes.

Pharmacologic Makeup (Typical Dental Office Protocol)

• Inhalation: N2O/O2 + volatile agents (Halothane, Enflurane)

• Intravenous induction agents: Thiopental sodium, Methohexital sodium

Four Classical Stages

1. Stage I – Analgesia (conscious, mild amnesia)

2. Stage II – Excitement / Delirium (loss of consciousness, irregular respirations, involuntary movements)

3. Stage III – Surgical anesthesia (desired plane; skeletal muscle relaxation, regular respirations)

4. Stage IV – Overdose → respiratory / cardiac arrest (must be avoided!)

Patient Preparation

• Comprehensive physical exam + indicated lab tests

• Informed consent (signed by patient/guardian)

• NPO: Nothing to eat or drink 8{-}12 h pre-op

Patient Recovery & Post-op Care

• Close monitoring until protective reflexes return; never leave patient unattended while regaining consciousness.

Mind-Body Medicine in Dentistry

• Non-pharmacologic anxiety & pain-reduction methods, often adjunctive to drugs.

• Techniques include:

  • Distraction (music, videos, conversation)

  • Relaxation / guided imagery

  • Deep breathing exercises

  • Biofeedback

  • Hypnosis

  • Acupuncture

• Benefits: lowers required drug dosages, enhances patient cooperation, promotes holistic care.

Documentation Requirements (Legal & Ethical)

• Thoroughly record:

  • Reviewed medical history

  • Pre- & post-op vital signs

  • Tidal volume settings if N2O/O2 used

  • Exact start & end times of anesthesia/sedation

  • Peak concentration or dosage delivered

  • Recovery time (minutes until discharge criteria met)

  • Any adverse reactions, complications, or patient complaints

• Accurate, contemporaneous documentation supports quality care & risk management.

These bullet-point notes capture all major and minor details, explanations, examples, contraindications, equipment descriptions, procedural steps, safety protocols, pharmacology, legal documentation, and mind-body considerations presented in Chapter 37 (Modern Dental Assisting, 14th ed.). They are designed to stand alone as a comprehensive study guide in preparation for examinations on dental anesthesia and pain control.