DAANCE Patient Assessment and Preparation 2 — Questions and Answers
Question 1: During pre-sedation airway assessment using the Mallampati classification, a Class IV finding indicates:
- Excellent visualization: soft palate, uvula, fauces, and pillars all visible
- Moderate difficulty: soft palate and uvula visible but pillars obscured
- Difficult airway: only the soft palate base visible
- No visibility of the soft palate - hardest class, predicting difficult intubation (Correct answer)
Correct answer: No visibility of the soft palate - hardest class, predicting difficult intubation
Mallampati Class IV: only the hard palate is visible with mouth fully open; soft palate is not visible. This strongly predicts difficult laryngoscopy and intubation.
Mallampati scoring: Class I = soft palate, uvula, fauces, pillars visible; Class II = soft palate, uvula, fauces visible; Class III = soft palate and base of uvula visible; Class IV = only hard palate visible. Higher classes correlate with increased likelihood of difficult laryngoscopy. Class III to IV findings require enhanced airway preparation before sedation.
Question 2: Which preoperative laboratory value is MOST important to check in a patient with a history of heavy alcohol use before IV sedation?
- Serum potassium level
- Prothrombin time/INR and liver function tests (Correct answer)
- Fasting blood glucose level
- Serum creatinine and BUN
Correct answer: Prothrombin time/INR and liver function tests
Heavy alcohol use causes hepatic disease, impairing coagulation factor synthesis (elevated PT/INR) and drug metabolism (altered sedative pharmacokinetics).
Chronic alcohol use leads to liver disease and reduced synthesis of clotting factors, resulting in elevated PT/INR and bleeding risk. Liver disease impairs benzodiazepine metabolism, prolonging sedation. Thrombocytopenia from alcohol suppression or portal hypertension adds further bleeding risk.
Question 3: A patient blood pressure before sedation is 148/92 mmHg. According to AHA classification this is:
- Normal blood pressure
- Elevated blood pressure
- Stage 1 hypertension (Correct answer)
- Stage 2 hypertension
Correct answer: Stage 1 hypertension
AHA 2017 guidelines: Stage 1 hypertension = SBP 130 to 139 or DBP 80 to 89. Stage 2 = SBP 140 or above or DBP 90 or above. A reading of 148/92 meets Stage 1 criteria.
2017 AHA/ACC classification: Normal < 120/80; Elevated 120-129/<80; Stage 1 HTN 130-139/80-89; Stage 2 HTN 140+/90+; Hypertensive crisis >180/120. At 148/92 (Stage 1), elective sedation may proceed with heightened monitoring, though physician consultation for values at or above 160/100 is prudent.
Question 4: Before administering IV sedation to a patient who takes clopidogrel (Plavix), the dental team should be aware that this drug:
- Causes sedative potentiation requiring reduced midazolam doses
- Inhibits ADP-mediated platelet aggregation, increasing bleeding risk (Correct answer)
- Prolongs QT interval and may cause cardiac dysrhythmias during sedation
- Induces hepatic CYP3A4 enzymes, reducing benzodiazepine effect
Correct answer: Inhibits ADP-mediated platelet aggregation, increasing bleeding risk
Clopidogrel irreversibly inhibits P2Y12 platelet receptors, impairing platelet aggregation for the platelet lifespan (approximately 7 to 10 days), increasing bleeding risk.
Clopidogrel is used in patients with coronary stents, stroke history, or acute coronary syndrome. Stopping it without cardiologist guidance risks stent thrombosis. For most dental procedures, clopidogrel can be continued with local hemostatic measures. Only major oral surgery warrants specialist consultation about medication modification.
Question 5: A consent discussion for IV sedation should include all of the following EXCEPT:
- Risks of IV sedation including respiratory depression
- Alternative approaches such as nitrous oxide or oral sedation
- A guarantee of complete amnesia during the procedure (Correct answer)
- What to expect after the procedure including discharge criteria
Correct answer: A guarantee of complete amnesia during the procedure
Guaranteeing amnesia is inappropriate and constitutes an improper promise. Informed consent should describe expected effects and realistic outcomes, not guarantees.
Complete amnesia is a common but not universal effect of benzodiazepine sedation. Promising it sets false expectations and creates medicolegal liability if the patient recalls events. Consent should explain that most patients experience significant amnesia but that complete memory loss cannot be guaranteed.
Question 6: A thyroid storm can be precipitated during dental sedation in a patient with uncontrolled hyperthyroidism by which common dental agent?
- Midazolam
- Epinephrine in local anesthetic (Correct answer)
- Nitrous oxide
- Lidocaine without vasoconstrictor
Correct answer: Epinephrine in local anesthetic
Epinephrine can precipitate or worsen thyroid storm in hyperthyroid patients by exacerbating catecholamine excess and cardiovascular instability.
Hyperthyroidism sensitizes adrenergic receptors, and exogenous epinephrine can trigger tachyarrhythmias, hypertensive crisis, or full thyroid storm. Patients with uncontrolled hyperthyroidism should not receive elective sedation. Plain local anesthetics (no epinephrine) are preferable when dental care is urgently needed.
DAANCE Patient Assessment and Preparation 2
During pre-sedation airway assessment using the Mallampati classification, a Class IV finding indicates: