Endoscopy: Bowel Preparation

Bowel Preparation

Adequacy

  • Adequate Bowel Preparation is Critical to Increase Visualization & Safety
  • Poor Preparation:
    • Increases Procedure Time
    • Increases Risk of Complication
    • Decreased Rate of Cecal Intubation
    • Increases Probability of Missed Lesions
  • Rate of Poor/Inadequate Preparation: 20-25% of All Colonoscopies

Contraindications to Bowel Preparation

  • Ileus
  • Bowel Obstruction
  • Severe Colitis (Inflammatory or Infectious)
  • Significant Gastric Retention
  • Neurologic or Cognitive Impairment that Prevents Safe Swallowing

Preparation Technique

  • Diet: Clear Liquid or Low-Residue (Low-Fiber) Diet for ≥ 1 Day Prior
  • Timing:
    • Split-Dose – Half is Taken the Evening Before & Half is Taken the Morning Of
      • Generally Better Tolerated & More Effective with Better Detection Rate
    • Single-Dose – Entire Preparation is Given at Once
      • Given the Evening Before for Morning Colonoscopy (Before 12:00 Noon)
      • Given the Morning of for Afternoon Colonoscopy (After 12:00 Noon)

Preparations

Polyethylene Glycol-Electrolyte Lavage Solution (PEG-ELS)

  • Ex: GoLYTELY or CoLyte
  • Isosmotic Agent – Minimizes Fluid Exchange with No Net Absorption or Secretion
  • Bisacodyl Can Be Used as an Adjunct

Sodium-Sulfate-Based Preparations

  • Hyperosmotic Agent

Sodium Phosphate Preparations

  • Hyperosmotic Agent
  • Complications:
    • Acute Phosphate Nephropathy
    • Electrolyte Abnormalities
    • Fluid Shift with Intravascular Hypovolemia
  • Contraindications: Heart Failure, Suspected IBD, Increased Risk of Electrolyte Abnormality, ACEI/ARB or Other Medications that Affect Renal Function

Magnesium Citrate

  • Not FDA Approved
  • Hyperosmotic Agent
  • Can Cause Significant Fluid & Electrolyte Shifts
  • Contraindications: Older Patients, Renal Disease, Heart Failure, ACEI/ARB or Other Medications that Affect Renal Function

Preparation Scales

Boston Bowel Preparation Scale (BBPS)

  • Sections:
    • Right Colon
    • Transverse Colon (Including Hepatic & Splenic Flexures)
    • Left Colon (Including Sigmoid Colon & Rectum)
  • Section Scores:
    • 0: Unprepared Colon with Mucosa Not Seen Because of Solid Stool that Cannot be Cleared
    • 1: Portion of the Mucosa Seen but Other Areas Not Seen Well Because of Staining, Residual Stool or Opaque Liquid
    • 2: Minor Amount of Residual Staining, Small Fragments of Stool or Opaque Liquid but Most Mucosa Seen Well
    • 3: Entire Mucosa Seen Well with No Residual Staining, Small Fragments of Stool or Opaque Liquid
  • Total Score: 0 (Poor) to 9 (Excellent)

Ottawa Bowel Preparation Scale (OBPS)

  • Sections:
    • Right Colon
    • Transverse Colon (Including Hepatic & Splenic Flexures)
    • Left Colon (Including Sigmoid Colon & Rectum)
  • Section Scores:
    • 0 (Excellent): Empty without Fluid
    • 1 (Good): Minimal Liquid Requiring No Aspiration
    • 2 (Fair): Liquid Requiring Aspiration to Clear
    • 3 (Poor): Requires Both Washing & Aspiration to Clear
    • 4 (Inadequate): Solid Stool, Not Washable
  • Total Score: 0 (Excellent) to 14 (Inadequate)