Download Chapter 10 outline

Pharmacology DH206
Chapter 10:General Anesthetics
Lisa Mayo, RDH, BSDH
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Application to Dentistry
• Drugs in this category produce CNS depression &
analgesia
• Reversible loss of consciousness
• Absence to painful stimuli
• DH = Nitrous
• Dentist = training & license to use moderate sedation
and/or general anesthesia
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Chapter 10 Outline
General Anesthetics
1. Terminology
2. Types of anesthesia
3. ASA Classification
4. Nitrous Oxide
5. General Anesthesia
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Terminology
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Terminology
1. Minimal sedation (anxiolysis = anti-anxiety)
• Drug-induced state. Pt can respond to commands
• Ventilation & cardiovascular unaffected
2. Moderate sedation (formerly called conscious sedation)
• Drugs used to induce sedation, lack of awareness, amnesia, analgesia
• Patient can respond to commands
• Monitor vitals, no intubation
• Licensed dentist can administer
3. Deep sedation
• Drug-induced depression of consciousness, pt cannot be easily aroused
• Monitor vitals, respiration closely
4. General anesthesia
• Unconsciousness, ventilator needed, hospital ONLY
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Types of Anesthesia
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Types of Anesthesia
Oral (enteral): need large initial dose, absorption NOT
predictable
2. Inhalation: sedation obtained via lungs, allows for rapid recovery
1) Nitrous oxide: anxiolysis ONLY, not for anesthesia
2) Volatile liquids: halogenated hydrocarbons or halogenated
ethers (p.118, TABLE 10-3)
3. IV
• Most predictable sedation
• IV moderate sedation = general anesthesia (don’t confuse the
2)
4. Combo: inhalation + Enteral (used in dentistry)
1.
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
All of the following statements are true about moderate
sedation EXCEPT which one?
a.
b.
c.
d.
Complete loss of protective reflexes
Total unconsciousness
Patent airway
Responds to physical stimulation
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
All of the following statements are true about moderate
sedation EXCEPT which one?
a.
b.
c.
d.
Complete loss of protective reflexes
Total unconsciousness
Patent airway
Responds to physical stimulation
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following procedures is used for anxiety
reduction, pain control and amnesia in the dental patient while
remaining responsive and cooperative during the dental
procedure?
a.
b.
c.
d.
Deep sedation
Local anesthesia
Moderate sedation
Minimal sedation
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following procedures is used for anxiety
reduction, pain control and amnesia in the dental patient while
remaining responsive and cooperative during the dental
procedure?
a.
b.
c.
d.
Deep sedation
Local anesthesia
Moderate sedation
Minimal sedation
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
ASA Classification
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
ASA Classification
ASA I – II
• Medically stable & able to receive anesthesia
ASA III – IV
• Medical consult necessary
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which ASA class described a patient with mild hypertension?
a.
b.
c.
d.
e.
I
II
III
IV
V
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which ASA class described a patient with mild hypertension?
a.
b.
c.
d.
e.
I
II
III
IV
V
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Nitrous Oxide
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Nitrous oxide
• Low potency
• IV + N2O/O2 + volatile anesthetic = excellent balanced
anesthesia produced
• Indications for use
1) Fearful patient
2) Cognitively, physically, medically compromised person
Gag reflex
3) Profound local anesthesia CANNOT be obtained
4) Cardiac conditions, HBP, asthma, cerebral palsy
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Nitrous Oxide Effects
• CNS sedation
BOOK CORRECTION: N2O2 DOES
NOT CAUSE AMNESIA P.120
 Resulting in analgesia and amnesia
• Cardiovascular effects
 Peripheral vasodilation
• Gastrointestinal effects
 Nausea and vomiting are uncommon but may occur
• Vitals remain wnl
• Pt conscious, reflexes intact
• Anxiety reduction
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Nitrous Oxide: Contraindications
• Pregnancy: NEVER in 1st trimester but controversy on
•
•
•
•
•
nitrous use after that
Communication difficulties
Emotional instability
Respiratory obstruction (nasal, blocked eustachian tubes)
COPD (Emphysema, Bronchitis)
Reformed drug and alcohol abusers
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Nitrous Oxide Abuse
• Neuropathy
• Liver, kidney problems
• Inhibit function & absorption of B12 (NBQ)
• Not in your book, but need to know
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia
Dental Office IV sedation
• Dentist needs separate license to administer
• Use a combo of meds to achieve goal (all highly lipid
soluble = FAST onset of action)
1) Benzodiazepines (Valium, Versed)
2) Opioids (fentanyl, morphine, meperidine)
3) Sedative/Hypnotic (propfol, ketamine)
4) Barbiturates (pentobarbital) if cannot use Benzo’s
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia
• Used in OMS
• Administration: IV drugs 1st then Inhalation
• Drugs rapidly produce unconsciousness and total
analgesia
• Progressive process that occurs in distinct stages
(Guedel’s signs) NEXT SLIDE
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia
GUEDEL Stages & Planes of Anesthesia: p.117, Table 10-1
1. Stage I: analgesia
• The patient is still conscious and can respond
• The end of stage I is marked by loss of
consciousness
• Nitrous oxide in dental office
2. Stage II: Delirium or Excitement
• Begins as loss of consciousness, irregular
respiration, hyper-responsiveness
3. Stage III: Surgical Anesthesia
• Return to regular respiration, 4 planes
4. Stage IV: Respiratory or medullary paralysis
• Cessation of respiration, circulatory failure
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia
Stage III: Surgical Anesthesia
• Most surgical procedures require this stage
• Guedel’s 4 signs you are in stage III (NBQ)
1) Pupil dilation
2) Tachycardia
3) Hypotension
4) Skeletal muscle relaxation
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
At which of the following stages of anesthesia is surgical
anesthesia attained?
a.
b.
c.
d.
1
2
3
4
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
At which of the following stages of anesthesia is surgical
anesthesia attained?
a.
b.
c.
d.
1
2
3
4
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Injectable Anesthetics
TYPICAL SEQUENCE FOR IV SEDATION
IV agent 1st
2. Inhalation agents: N2O2, Halogenated hydrocarbon
1.
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Injectable Drug
Class
Drugs
Benzodiazepine
Valium, Versed
Opioids
Fentanyl, Morphine, Meperidine
Sedative/Hypnotic
Propfol, Ketamine
Barbiturate
Phenobarbital, Thiopental,
Methohexital(Brevital)
Inhalation Anesthetics
Halothane(Fluothane)
PROTYPE
Desflurane(Suprane)
NEWER
Sevoflurane(Ultane)
NEWER
Isoflurane(Forane)
Enflurane(Ethrane)
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Injectable Drug
Class
Drug
Benzodiazepine
Valium, Versed
Opioids
Fentanyl, Morphine, Meperidine
Sedative/Hypnotic
Propfol, Ketamine
Barbiturate
Phenobarbital, Thiopental,
Methohexital(Brevital)
Notations
Catatonic state, no loss consciousness
ALL pose risk for resp depression!
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Inhalation Anesthetics
Inhalation Anesthetics
Halothane(Fluothane)
PROTYPE
Desflurane(Suprane)
NEWER
Sevoflurane(Ultane)
NEWER
Isoflurane(Forane)
Enflurane(Ethrane)
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Inhalation Anesthetics
• 2 classes: gases or volatile liquids
1. Nonhalogenated drugs
2. Halogenated drugs: only used by dentist or
anesthesiologists in hospital setting (next slide)
• Uses
• Maintenance after induction of IV agent
• Measured in terms of partial pressure (not mg/mL like oral
agents)
• MAC (minimal alveolar concentration)
• Inspired concentration of anesthetic to induce surgical
anesthesia in 50% of patients
• Used to measure & compare potency of the different
drugs
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following agents is considered to be a gas?
a.
b.
c.
d.
Nitrous oxide
Fentanyl
Propofol
Diazepam
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following agents is considered to be a gas?
a.
b.
c.
d.
Nitrous oxide
Fentanyl
Propofol
Diazepam
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following inhalation anesthetics does not cause
respiratory depression and hypotension?
a.
b.
c.
d.
Nitrous oxide
Enflurane
Isoflurane
Halothane
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following inhalation anesthetics does not cause
respiratory depression and hypotension?
a.
b.
c.
d.
Nitrous oxide
Enflurane
Isoflurane
Halothane
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
General Anesthesia Drugs
Adverse Reactions: Table 10-2,p.129
1.
2.
3.
4.
Cardio
• Hypotension
• Hypertension
• Arrhythmias
CNS
• Pain
• Muscle weakness
• Sleepy
GI
• Constipation
• Nausea, vomiting
Respiration
• Difficulty breathing
• Sore throat
• Hypoxia (low oxygen)
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Propofol is preferred over thiopental as an IV anesthetic
because of its
a.
b.
c.
d.
Recovery characteristics
Can be taken orally
Long onset of action
Prolonged duration of action
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Propofol is preferred over thiopental as an IV anesthetic
because of its
a.
b.
c.
d.
Recovery characteristics
Can be taken orally
Long onset of action
Prolonged duration of action
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following side effects is common after general
anesthesia?
a.
b.
c.
d.
Diarrhea
Esophageal reflux
Nausea and vomiting
Muscle weakness
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
NBQ
Which of the following side effects is common after general
anesthesia?
a.
b.
c.
d.
Diarrhea
Esophageal reflux
Nausea and vomiting
Muscle weakness
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.