Pre-anesthetic Patient Assessment

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Pre-anesthetic Patient Assessment
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Thorough Review of Medical History

• It is very important to evaluate the patients
  ability to tolerate local anesthetics and/or
  vasoconstrictors, allergic responses, and current
  medications
• To determine if contraindications or
  modifications to treatment are needed
• Help to prevent or minimize complications and
  emergencies

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Contraindications to LAs and Vasoconstrictors

• Absolute contraindications the drug should not
  be administered under any circumstances
• Relative contraindications the drug should be
  avoided if a substitute is not available, a
  minimal dose of the drug may be used

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Hyperthyroidism

• Exaggerated response to vasoconstrictor
• Absolute contraindication of vasoconstrictor use
  in an uncontrolled hyperthyroid case
• Limited use of vasoconstrictors indicated with
  surgically corrected or medicated-controlled
  hyperthyroid conditions

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Atypical Plasma Cholinesterase

• 1 out of every 2,820 persons
• Not always clinically significant symptoms
• Usually found when patient is under general
  anesthesia
• Missing enzyme that breaks down esters in the
  blood (plasma)
• Relative contraindication to esters
• Use amide anesthetics when possible

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Methemoglobinemia

• Congenital or acquired condition
• Hemoglobin is converted to methemoglobin which
  has less oxygen carrying capacity
• (potential of cyanosis)
• Respiratory distress (prilocaine or articaine)
• Relative contraindication to prilocaine and
  articaine, minimize dose if it must be used
• Use other anesthetics if available

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Malignant Hyperthermia

• Malignant Hyperthermia (MH) is an inherited
  disorder in which affected individuals do not
  react appropriately to certain general anesthesia
  drugs such as halothane, cyclopropane, and the
  muscle relaxant succinylcholine. This disorder is
  characterized by the development of a sudden and
  rapid high fever, muscle rigidity, and an
  irregular heartbeat (cardiac arrhythmia), after
  the administration of general anesthesia or
  certain muscle relaxants.

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Malignant Hyperthermia

• One of the most life-threatening complications
  associated with the administration of general
  anesthesia
• Relative contraindication to use of amides
• Consult with physician is strongly recommended

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Liver Dysfunction

• Difficulty metabolizing amides, potential for
  overdose in significant liver dysfunction
• Relative contraindication to amides
• Use amides at minimal doses
• Consult with physician

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Renal Dysfunction

• Excretion of local anesthetic is difficult with
  significant renal dysfunction, potential for
  overdose
• Use anesthetic agents in minimal doses
• Consult with physician

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Pregnancy

• May have complications
• Relative contraindication to elective
• treatment during the first trimester
• Use local anesthetics at minimal doses
• Anesthetics and vasoconstrictors do cross the
  placenta, but are not teratogens

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High Blood Pressure

• OK to administer anesthesia with vasoconstrictor
  judiciously
• Take patients blood pressure prior to the
  injection
• Monitor patients blood pressure

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Prosthetic Heart Valve, Heart Transplant

• Local anesthesia does not require antibiotic
  prophylaxis (pre-med) with the exception of the
  PDL injection, but the patient more than likely
  will be premedicated for the dental treatment
  requiring the anesthetizing

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Patient Medications

• Have the patient complete a thorough medical
  history
• Question the patient regarding yes responses to
  questions
• Look up all medications in a drug reference text
  for any contraindications
• Local anesthetics have few interactions with
  other prescribed drugs

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Patient Medications

• Vasoconstrictors may interact with
• Tricyclic antidepressants (Elavil)
• Phenothiazines (antipsychotic drugs)
• Beta-receptor blockers (propranolol)-increase
  blood pressure
• Adrenergic neuron blockers- increase BP
• Use minimal dose or use anesthetic without
  vasoconstrictor

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Sulfa Drugs

• Esters inhibit the bacteriostatic action of
  sulfonamides
• Do not use esters (procaine, tetracaine)
• Use amide anesthetics
• Sulfa drugs and ester anesthetics are used rarely
  today, so this drug interaction is unlikely

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Cimetidine (Tagamet)

• Modifies the biotransformation of lidocaine in
  the liver
• Little clinical significance unless the patient
  has congestive heart failure (CHF)
• Relative contraindication to the use of amide
  local anesthetics - minimal doses should be used

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Allergy

• An allergy is a hypersensitive reaction acquired
  through exposure to a specific substance
  (allergen) re-exposure to the allergen increases
  ones potential to react.
  
• Note previous local anesthesia allergies
  documented on patient medical history
• Only 1 of all reactions during administration of
  local anesthetics are true allergic reactions
• Rare with amides
• Based on allergy, may elect to use alternative
  anesthesia
• 
  

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Sulfite Allergy

• Sodium bisulfite or metasulfite
• Bisulfites are antioxidants which are commonly
  sprayed on fruits and vegetables to keep them
  appearing fresh
• Often associated with asthmatics
• Use a plain anesthetic since sodium bisulfite is
  used to preserve the vasoconstrictor in
  anesthetic solutions

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Preanesthetic Patient Assessment Quiz

• An absolute contraindication to using a local
• anesthetic means
• a. The anesthetic can be used with the
  maximum
• recommended dose
• b. The anesthetic can be used in minimal
  doses
• c. The anesthetic should not be used under
  any
• circumstances
• d. The anesthetic can be used without a
  vasoconstrictor

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• 2. A relative contraindication to using a local
• anesthetic means
• a. The anesthetic can be used with the
  maximum
• recommended dose
• b. The anesthetic can be used in minimal
  doses
• c. The anesthetic should not be used under
  any
• circumstances
• d. The anesthetic should be used without a
• vasoconstrictor

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• 3. Your patient has uncontrolled
  hyperthyroidism. What is
• the indication for local anesthesia use?
• a. The use of local anesthetic is an
  absolute
• contraindication
• b. The use of local anesthetic with a
  vasoconstrictor is
• an absolute contraindication
• c. The use of local anesthetic is a
  relative contraindication
• d. The use of local anesthetic with a
  vasoconstrictor is a
• relative contraindication

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• 4. What anesthetic(s) is/are contraindicated for
  a
• person with methemoglobinemia?
• a. Articaine
• b. Lidocaine
• c. Prilocaine
• d. a and b
• e. a and c

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• 5. Which of the following is/are true about
• malignant hyperthermia?
• a. One of the most life threatening
  complications
• of general anesthesia
• b. A relative contraindication to amides
  exists
• c. No contraindication to esters exists
• d. Consultation with physician is strongly
• recommended
• e. All of the above

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• 6. Your patient has a liver dysfunction. Which
  of the
• following is NOT true?
• a. There is a relative contraindication to
  amides
• b. There is an absolute contraindication to
  amides
• c. You can use amides in minimal doses
• d. Consultation with physician is recommended

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• 7. Esters counteract the bacteriostatic action of
  sulfa drugs.
• Esters and sulfa drugs are rarely used today,
  so this drug
• interaction is highly unlikely.
• a. The first part of the statement is true,
  the second part is true.
• b. The first part of the statement is true,
  the second part is false.
• c. The first part of the statement is false,
  part of the statement is true.
• d. The first part of the statement is false,
  the second part is false.

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• 8. Cimetidine (Tagamet) modifies the
  biotransformation of
• __________ in the liver, therefore a patient
  taking Tagamet
• should not receive this anesthetic.
• a. Articaine
• b. Lidocaine
• c. Mepivacaine
• d. Prilocaine

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• 9. What is atypical plasma cholinesterase?
• a. A liver dysfunction
• b. The blood is missing the enzyme that
  breaks
• down amides
• c. The blood is missing the enzyme that
  breaks
• down esters
• d. The blood will not form a clot

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• 10. Your patient has a sulfite allergy. What
  anesthetic
• should you choose to use on this
  patient?
• a. An anesthetic without a
  vasoconstrictor
• b. An anesthetic with a vasoconstrictor
• c. An ester
• d. An amide