Colonoscopy is one of the most common procedures in medicine today. This lectures covers the complications associated with colonoscopy, including the risk factors and management.

1. Colonoscopy Complications
Dr Jarrod Lee
Gastroenterologist and Advanced Endoscopist
Mount Elizabeth Novena Hospital
1Residents Lecture, 2012

2. Scope
• Cardiopulmonary complications
• Perforation
• Hemorrhage
• Others
2

3. Cardiopulmonary Complications
3

4. CORI Database1
• Prospective database of > 300,000 procedures
• Incidence:
– Occurs in 0.9% of cases, 1.1% of colonoscopies
– Accounts for 67% of unplanned events
– Likely under-reported/ under-estimated
• Cardiopulmonary complications:
– Most common: transient hypoxia, bradycardia, hypotension
– 7.65% needed supplemental O2, 0.31% needed IV fluids
– Reversal of sedation: occurred in 0.5%
4
1. Sharma et al. GIE 2007.

5. Moderate Sedation
• Systemic review of moderate sedation RCTs1
– 36 studies, 3918 patients, routine endoscopy
• Sedation benefits: higher patient satisfaction,
cooperation & willingness for 2nd procedure
• Complication rates:
– Overall: 6-11% hypoxemia; 5-7% hypotension
– Hypoxemia risk: 18% for midazolam alone vs 11% for
midazolam + narcotic
– Propofol vs midazolam: no difference in complications
or procedure times, but better patient satisfaction
5
1. McQuaid et al. GIE 2008.

6. Cardiovascular Events in Colonoscopy
• Arrhythmias, Angina, AMI, CVA, TIA
• Increased in 30 day post-procedure period
– CORI database1: 1.4 per 1000
– Medicare (66-95 yrs)2: 1.030 per 1000 vs 0.885
(matched controls)
• Risk factors:
– Advanced age, co-morbidities
– Stopping aspirin & anti-platelet agents
– Polypectomy
6
1. Ko et al. Cin Gastroenterol Hepatol 2010. 2. Warren et all. Ann Intern Med 2009.

7. Managing Cardiopulmonary Risk
• Need to identify high risk patients pre-procedure
& consider benefit of
– Delaying procedure
– Co-managing case
• Appropriate monitoring
• Patient position
• Balance risk of antiplatelet & anticoagulant
therapy
7

8. Perforation
8

9. Perforation
• Mechanisms:
– Mechanical forces against bowel wall, barotrauma,
direct result of therapeutics
• Incidence rate:
– < 0.3% in large studies; generally < 0.1%
• Risk factors1:
– Polypectomy: biggest risk factor
– Advanced age, male sex
– Low volume endoscopist
9
1. Rabeneck et al. Gastroenterol 2008.

10. 10

11. Management & Prevention
• Diagnosis:
– Early symptoms: persistent abd pain & distension
– Late: peritonitis
– Plain X ray may be normal; do CT if high index of suspicion
• Management:
– Surgical consult: best outcomes with early surgery
– Endoscopic clipping
• Prevention:
– Cold techniques, ? saline lift
– Avoid pure coagulation current
11

12. Hemorrhage
12

13. Hemorrhage
• Most often due to polypectomy:
– Immediate: up to 12H post procedure
– Delayed: from 12H to 30 days
– Medicare database1: 8.7 per 1000 colonoscopies with
polypectomy vs 2.1-3.7 without
• Incidence:
– 0.1-0.6%
– May be up to 24% for polypectomy of large polyps
13
1. Warren et all. Ann Intern Med 2009.

14. Risk Factors
• Large polyp, number of polyps, polyp histology
• Hypertension
• Warfarin
• Aspirin + clopidogrel
• ? Aspirin alone: multiple large studies
• Cut/ blended current: immediate hemorrhage
• Coagulation current: delayed hemorrhage
14

15. Prophylaxis
• Clips:
– Mixed results, even when used for ‘high risk’ polyps
• Adrenaline injection:
– May reduce immediate bleeding, but no effect on
delayed bleeding
• Endoloop:
– RCT proven for pedunculated polyp > 1cm1
• Mini snare resection without electrocautery2
15
1. Iishi et al. GIE 1996. 2. Tappero et al. GIE 1992.

16. Management
• Immediate hemorrhage
– Usually directly visualized from polypectomy site
– Usually amenable to endoscopic tx
– 1st line tx: adrenaline injection or clip placement
– Snaring stalk
• Delayed hemorrhage
– Usually needs hospitalization & repeat colonoscopy
• Radiologic or surgical management also effective
16

17. Others
17

18. Mortality
• Review of > 370,000 colonoscopies (database
and prospective studies)1:
– Pooled death rate: 0.03%
– All cause mortality: 0.07%
– Colonoscopy specific mortality: 0.007%
18
1. Ko et al. Gastrointest Endosc Clin N Am 2010.

19. Post-polypectomy Electrocoagulation Syndrome
• Incidence: < 0.2%
• Mechanism:
– Due to electrocoagulation injury to bowel wall
– Induces transmural burn without evidence of perforation
• Presentation: 1-5 days after colonoscopy
– Fever, localized pain & peritoneal signs, leukocytosis
– Normal CT
• Management:
– Does not require surgery
– NBM, IV hydration + antibiotics
19

20. Infection
• Transient bacteremia occurs in ~4% (0-25%)
• Infection rare
– Individual case reports, but no definite causal link
• No proven benefit for antibiotic prophylaxis:
– AHA & ASGE current guidelines recommend against
antibiotic prophylaxis
• All reported cases of infection transmission due
to defective equipment & reprocessing
– See Multisociety Guidelines 2011
20

21. Gas Explosion
• Rare but serious
– 9 case reports to date, all resulted in perforation
• Mechanism:
– Combustible levels of hydrogen or methane in colon
– Electrosurgical energy (electrocautery or APC)
• Risk factors:
– Non absorbable or incompletely absorbed
carbohydrate preparations e.g. lactulose
– Incomplete colonic cleansing, enemas
• Prevention: good bowel prep
21
1. Ladas et al. WJG 2007.

22. Gastrointestinal Symptoms
• Minor but common:
– Bloating: 25%
– Abdominal pain/ discomfort: 5-10%
– Diarrhea, bleeding, nausea: 4-6%
• Prevention:
– Appropriate techniques: looping, gas insufflation
– CO2, water
• Generally mild and self limited (2 days)
22

23. Bowel Preparation
• Sodium phosphate preparations:
– Low volume, better tolerated
– Risk of acute phosphate nephropathy, fluid overload
– High risk: elderly, renal impairment, ACE/ ARB tx,
fluid overload states
• PEG:
– Large volume, difficult to tolerate
– Does not lead to electrolyte/ fluid shifts
– Nausea/ vomiting, abdominal discomfort common
– Rare complications: aspiration, Mallory Weiss tears
23

24. Summary
• Although rare, colonoscopy complications are
potentially severe & life threatening
• Cardiopulmonary complications most common
– Careful patient selection, risk management and peri-
procedural monitoring important
• Polypectomy markedly increases risk
– Risk of increases 9-10x for all complications
– Hemorrhage can be delayed up to 30 days
– Use of electrocautery (especially hot biopsy forceps1)
particularly high risk
24
1. Gilbert et al. Status evalution: hot biopsy forceps. GIE 1992.

25. Take Home Points
• Reduce:
– Understand complications & their risk factors
– Careful patient selection & risk management
– Proper endoscopic technique & patient monitoring
• Recognize:
– Complications are inherent
– Early diagnosis & prompt multi-disciplinary intervention
• Review:
– All complications should be reviewed as part of
continuing quality improvement & education process
– Disclose medical errors (JCI requirement)
25

26. Questions?
26