DAANCE Managing Systemic Diseases 2 — Questions and Answers
Question 1: A dental patient with Type 1 diabetes mellitus scheduled for morning sedation is MOST at risk for which perioperative complication?
- Hyperglycemic hyperosmolar state
- Hypoglycemia due to fasting and insulin effects (Correct answer)
- Diabetic ketoacidosis within 30 minutes of sedation
- Increased bleeding due to platelet dysfunction
Correct answer: Hypoglycemia due to fasting and insulin effects
Type 1 diabetic patients who fast for NPO requirements may develop hypoglycemia, especially if they took their usual insulin dose without eating.
Morning NPO requirements combined with ongoing insulin action significantly increase hypoglycemia risk. Pre-operative management should include checking blood glucose before sedation, holding or adjusting insulin doses, and scheduling the patient as the first case. Glucose monitoring during sedation is essential.
Question 2: For a patient on warfarin therapy, the dental team should review which laboratory value before a procedure involving significant bleeding risk?
- Partial thromboplastin time (aPTT)
- International normalized ratio (INR) (Correct answer)
- Platelet count only
- Complete blood count (CBC) with differential
Correct answer: International normalized ratio (INR)
The INR quantifies the anticoagulant effect of warfarin. An INR at or below 3.5 is generally acceptable for most dental procedures.
Warfarin affects the extrinsic (PT/INR) pathway. INR 2.0 to 3.0 is therapeutic for most indications. For simple dental extractions, an INR at or below 3.5 is acceptable without altering warfarin. Stopping warfarin carries a risk of thromboembolism greater than the bleeding risk from most dental procedures.
Question 3: A patient with severe obstructive sleep apnea (OSA) presents for IV sedation. The primary concern during sedation is:
- Increased bleeding from CPAP-related upper airway trauma
- Exaggerated upper airway obstruction and respiratory depression sensitivity (Correct answer)
- Seizure activity from hypoxia-induced cortical irritability
- Hypertensive crisis from catecholamine release
Correct answer: Exaggerated upper airway obstruction and respiratory depression sensitivity
OSA patients have anatomically compromised upper airways and are highly sensitive to opioids and sedatives, greatly increasing the risk of airway obstruction during sedation.
OSA is characterized by repetitive upper airway collapse during sleep. Sedatives and opioids relax pharyngeal musculature and blunt arousal responses, reproducing and worsening this obstruction. OSA patients often require reduced opioid doses, careful positioning, continuous capnography, and immediate availability of airway rescue equipment.
Question 4: A patient with a known latex allergy requires dental sedation. The anesthesia team must:
- Premedicate with diphenhydramine and proceed normally
- Ensure the environment is latex-free, including gloves, IV tubing, and mask components (Correct answer)
- Only perform nitrous oxide sedation to avoid IV access
- Reschedule the patient to a hospital setting
Correct answer: Ensure the environment is latex-free, including gloves, IV tubing, and mask components
Latex allergy requires a completely latex-free environment. Many medical devices - gloves, IV bags, tubing, blood pressure cuffs - may contain latex.
Latex hypersensitivity can range from contact dermatitis to life-threatening anaphylaxis. A latex-free setup includes: nitrile/vinyl gloves, latex-free IV tubing and stopcocks, latex-free oxygen delivery equipment, and latex-free dental materials. The patient should ideally be scheduled as the first case of the day.
Question 5: Which modification is indicated for a patient with severe aortic stenosis (AS) scheduled for elective dental sedation?
- Administer aggressive IV fluid loading to maintain high preload
- Use low-dose vasodilators to compensate for the stenotic valve
- Consult the cardiologist; sedation may require advanced monitoring or hospital-based care (Correct answer)
- Proceed with standard IV sedation without modification
Correct answer: Consult the cardiologist; sedation may require advanced monitoring or hospital-based care
Severe AS represents high cardiac risk. These patients tolerate neither hypo- nor hypertension well. Cardiology consultation is essential before elective sedation.
Severe AS (valve area less than 1.0 cm2) restricts cardiac output and makes patients extremely sensitive to preload reduction and tachycardia. In-office sedation may be contraindicated; hospital-based care with invasive monitoring may be required. Elective dental procedures should be postponed until AS is surgically corrected.
Question 6: A patient with chronic renal failure on hemodialysis presents for sedation. Which pharmacokinetic alteration is most clinically important?
- Increased hepatic first-pass metabolism of IV opioids
- Reduced protein binding and accumulation of renally-cleared drug metabolites (Correct answer)
- Faster gastric emptying leading to altered oral drug absorption
- Increased volume of distribution requiring higher initial doses
Correct answer: Reduced protein binding and accumulation of renally-cleared drug metabolites
Renal failure reduces plasma protein (albumin) binding, increasing free drug fraction, and allows accumulation of active metabolites normally excreted renally.
Uremia reduces plasma albumin, increasing the free fraction of protein-bound drugs. Active metabolites of morphine (morphine-6-glucuronide) and meperidine (normeperidine with seizure risk) accumulate in renal failure. Fentanyl is preferable because its metabolites are inactive. Dose reduction and increased monitoring are indicated.
DAANCE Managing Systemic Diseases 2
A dental patient with Type 1 diabetes mellitus scheduled for morning sedation is MOST at risk for which perioperative complication?