What are the steps to the Drug-Induced Sleep Endoscopy (DISE) procedure and grading system?

Drug-Induced Sleep Endoscopy (DISE) Procedure and Grading

Drug-Induced Sleep Endoscopy (DISE) is a valuable diagnostic tool that allows for real-time assessment of upper airway obstruction during induced sleep, providing critical information for selecting appropriate surgical and non-surgical interventions for patients with sleep-related breathing disorders.

Preprocedural Assessment

Before performing DISE, a thorough patient evaluation should include:

• ASA physical status classification (patients with ASA I-III are appropriate candidates for sedation by an endoscopist) 1

• Identification of high-risk patients:

  • Significant cardiac or pulmonary disease
  • Neurologic or seizure disorders
  • History of stridor, snoring, or sleep apnea
  • Previous adverse reactions to sedation
  • Current medications and allergies
  • Alcohol or substance abuse
  • Time of last oral intake 1

• ASA class IV-V patients should be considered for anesthesia specialist assistance 1

Equipment Requirements

• Flexible fiberoptic nasendoscope
• Video recording system
• Monitoring equipment:
  • Pulse oximetry
  • Automated non-invasive blood pressure device
  • Continuous electrocardiography (for high-risk patients)
  • Capnography (recommended) 1
• Emergency equipment:
  • Cardiac defibrillator
  • Oral and nasal airways
  • Ambu-bag for positive-pressure ventilation
  • Reversal agents (flumazenil, naloxone) 1

DISE Procedure Steps

1. Patient Positioning

   • Position patient in supine position similar to natural sleeping position
   • Ensure proper head and neck alignment

2. Baseline Airway Assessment

   • Perform initial awake endoscopy to establish baseline anatomy
   • Document pre-sedation airway status

3. Sedation Administration

   • Common sedative agents:

     • Propofol (most commonly used)
     • Midazolam (often combined with opioids)
     • Target moderate sedation initially 1

   • Titrate sedation to achieve:

     • Loss of response to verbal stimuli
     • Maintenance of spontaneous breathing
     • Snoring or evidence of upper airway obstruction 2, 3

4. Endoscopic Examination

   • Insert flexible nasendoscope when appropriate sedation level achieved
   • Systematically evaluate the upper airway from nasopharynx to hypopharynx
   • Observe patterns of collapse during induced sleep
   • Document findings at each anatomical level 4

5. Monitoring During Procedure

   • Continuously monitor:
     • Oxygen saturation
     • Heart rate and blood pressure (every 3-5 minutes)
     • Level of sedation using validated scales (e.g., RASS or SAS) 1
   • Maintain sedation at target level:
     • RASS score of -2 to 0 or SAS score of 3-4 1

6. Recovery and Post-Procedure Care

   • Monitor patient until return to baseline consciousness
   • Document recovery parameters
   • Provide discharge instructions 1

DISE Grading Systems

The most widely used classification system is the VOTE Classification:

VOTE Classification System

1. V - Velum/Soft Palate

   • Patterns: Anterior-posterior collapse, lateral collapse, concentric collapse

2. O - Oropharyngeal Lateral Walls

   • Patterns: Lateral collapse, concentric collapse

3. T - Tongue Base

   • Patterns: Anterior-posterior collapse, concentric collapse

4. E - Epiglottis

   • Patterns: Anterior-posterior collapse, lateral collapse, complete collapse 5, 4

For each site, grade the degree of obstruction:

• 0 = No obstruction (0-25%)
• 1 = Partial obstruction (25-75%)
• 2 = Complete obstruction (>75%) 4

Critical Considerations and Pitfalls

• Sedation Management

  • Avoid oversedation that may induce deeper levels than intended
  • Be prepared to rescue patients whose sedation becomes deeper than planned
  • Practitioners should possess ACLS certification 1

• Interpretation Challenges

  • Different sedative agents may produce variable patterns of collapse, especially at the tongue base 3
  • Findings during drug-induced sleep may not perfectly match natural sleep 3

• Standardization

  • Use consistent technique and documentation
  • Apply standardized classification system
  • Record procedure for later review and comparison 6, 4

• Quality Assurance

  • Monitor outcomes including cardiopulmonary complications, use of reversal agents, and unplanned procedure terminations 1
  • Implement quality improvement processes to identify and address adverse events

DISE provides valuable information for surgical planning and non-surgical treatment selection that cannot be obtained during awake examination. When performed with proper technique and interpreted systematically, it significantly enhances the management of patients with sleep-related breathing disorders.