Comparisons of SWI, WWI and CI in Potentially Difficult Colonoscopy.
Condition: Colonoscopy
Study type: Interventional

Summary: 
      Colonoscopy insertion is technically challenging, time-consuming, and painful, especially for
      the sigmoid. It is reported that the difficult colonoscopy score (DCS) >1 can predict the
      difficulty during colonoscopy. Patients with DCS>1 had longer insertion time, higher pain
      score and needed more abdominal compression and position changes. As reported, water-aided
      method colonoscopy examination is an important and useful method because it reduces
      discomfort and increases cecal intubation rate compared with usual air insufflation method.
      But a longer time was consumed for scope insertion and cecal intubation in the traditional
      water-aided method colonscopy(the whole water immersion). To avoid these disadvantages ,we
      modified whole colon water immersion(WWI) method to the sigmoid colon water immersion(SWI),
      where the most difficult and painful part of colonoscopy resides. If water immersion is
      limited to the sigmoid colon in such patients, would it be more efficient and less time
      consuming?

      The aim of this study was to investigate the application of water-aided method on cecal
      intubation time in potentially difficult colonoscopy. This prospective, randomized controlled
      study allocated patients who's difficult colonoscopy score(DCS) >1 (18-80 years) to
      sigmoid-colon water immersion(SWI), whole colon water immersion(WWI) or carbon dioxide (CO2)
      insufflation (CI) group (1:1:1). The primary outcome was cecal intubation time. The secondary
      outcomes included the maximum pain score (0=none,10=most severe) during the insertion phase
      in left, transverse and right colon; cecal intubation rate; adenoma detection rate(ADR);
      bowel preparation quality; withdrawal time(from cecum to rectum excluding time for biopsy and
      polypectomy); willingness to undergo a repeat unsedated colonoscopy; number of abdominal
      compressions, position change during the insertion. Patients were educated to understand the
      meaning of visual analogue scale (VAS) (0 = no pain, 10 = most severe) and to report their
      maximum pain scores during the insertion through each colonic segment. Descriptive statistics
      were used to summarize demographic and baseline data. Analyses were performed with SPSS
      software version 24.0 for Windows (SPSS Inc, IBM Company).
    

Detailed description: 
      Introduction: Colonoscopy insertion is technically challenging, time-consuming, and painful,
      especially for the sigmoid. Many factors have been found to affect the difficulty of
      colonoscope insertion, such as age, gender, body mass index, history of abdominal surgery and
      operator ect. It is reported that the difficult colonoscopy score (DCS) >1 can predict the
      difficulty during colonoscopy. DCS=1*A(1 if age≥65y, 0 if <65y) + 2*B (1 if BMI <18.5, 0 if
      BMI≥18.5) + 1*C (1 if colonoscopist is junior, 0 if senior)+ 1*S(1 if sleep quality was fair
      or bad, 0 if excellent or good). Patients with DCS>1 had longer insertion time, higher pain
      score and needed more abdominal compression and position changes. For these potentially
      difficult cases we can use special intubation techniques such as water-aided or cap-assisted
      method at the very start to avoid of excessive insertion time, increased discomfort and even
      unnecessary adverse events.

      Water-aided method colonoscopy examination is an important and useful method because it
      reduces discomfort and increases cecal intubation rate compared with usual air insufflation
      method. This examination is usually performed using two different methods: water immersion
      and water exchange. In the water immersion method, the water is infused into the colon
      beginning with the scope inserted into the anus during examination until the scope reaches
      the cecum. The water is evacuated during colonoscope withdrawal. In the water exchange
      method, the water is evacuated during colonoscope advancement until the cecum is reached. The
      air pump of the endoscopy machine is turned off during examination in both procedures. The
      aim of this study was to investigate the application of water-aided method on cecal
      intubation time in potentially difficult colonoscopy. We chose water immersion method rather
      than water exchange for this evaluation because water immersion, characterized by suction
      removal of the infused water predominantly during withdrawal, is more appropriate for
      reducing the cecal intubation time. Further more ,as reported, left-colon water exchange(LWE)
      shorten the insertion time while preserving the benefits of whole colon water exchange(WWE).
      We modified whole colon water immersion(WWI) method to the sigmoid colon water
      immersion(SWI), where the most difficult and painful part of colonoscopy resides. If water
      immersion is limited to the sigmoid colon in such patients, would it be more efficient and
      less time consuming? Methods:This prospective, randomized controlled study allocated patients
      who's difficult colonoscopy score(DCS) >1 (18-80 years) to sigmoid-colon water
      immersion(SWI), whole colon water immersion(WWI) or carbon dioxide (CO2) insufflation (CI)
      group (1:1:1). Patients were randomized to SWI, WWI or CI group according to a
      computer-generated randomization list in 1:1:1 ratio. Group assignments were revealed
      immediately before the insertion of colonoscopy by a researcher , who did not participate in
      data collection and data analysis. The monitor screen was placed over the head of patients to
      keep them from knowing the insertion method. Endoscopists and assisting nurses were not
      blinded. For the bowel preparation, all patients were instructed to take low-fiber diet for
      lunch and clear liquid diets for dinner the day before examination. They ingested 2L of PEG
      powder (WanHe Pharmaceutical Co, Shenzhen, China) diluted with water within 2 h, between 4:00
      AM and 5:00 AM on the day of the examination. Those with chronic constipation received an
      additional 2L of PEG solution on the evening prior to the examination. Drinking more clear
      water and pacing back and forth after purgatives were encouraged to enhance laxative effect.
      The time interval between preparation and colonoscopy was limited to less than 5 h to ensure
      the quality of bowel preparation.

      Endoscopic procedure Two endoscopists (WBH and YJ) with extensive experience in both air
      (>5000) and water methods (>500) performed the colonoscopies. The standard adult colonoscope
      (EC-600WM, Fujinon, Beijing) was used. Patients were placed in the left lateral position at
      the beginning of the procedure. Maneuvers such as abdominal compression and position change
      were implemented if needed (e.g. when looping, paradoxical movement or lack of advancement
      occurred). Successful cecal intubation was confirmed by the visualization of appendiceal
      orifice or ileocecal valve with the tip of the colonoscope touching the base of the cecum.
      For the AI method, air was insufflated through out the whole procedure for advancement and
      inspection when needed. In the WWI method,the air supply was turn off until the cecum was
      reached. For adequate lumen distention to advance the colonoscope tip, warm water which
      stored in 1L bottles and maintained 37°C with a water bath, was instilled intermittently into
      the colon through the auxiliary working channel of colonoscope using a footswitch-controlled
      flushing pump. For patients allocated to SWI group, air pump would be turned off and the
      procedure would be switched from water immersion method to air insufflation method after
      successful passage through the descending sigmoid junction.

      The primary outcome was cecal intubation time. The secondary outcomes included the maximum
      pain score (0=none,10=most severe) during the insertion phase in left, transverse and right
      colon; cecal intubation rate; adenoma detection rate (ADR); bowel preparation quality;
      withdrawal time(from cecum to rectum excluding time for biopsy and polypectomy); willingness
      to undergo a repeat unsedated colonoscopy; number of abdominal compressions, position change
      during the insert.

      Descriptive statistics were used to summarize demographic and baseline data. Quantitative
      variables are expressed as means and standard deviations and analyzed by ANOVA followed by
      Bonferroni test for multiple comparisons. Categorical variables in three groups were compared
      with chi-square test or Fisher exact test when appropriate. All p-Values were two-sided and
      those < 0.05 were considered to be significant. Analyses were performed with SPSS software
      version 24.0 for Windows (SPSS Inc, IBM Company).
    

Intervention name(s): whole colon water immersion and sigmoid water immersion
Intervention type(s): Procedure
Intervention description(s): we chose water immersion method instead of the triaditional method of carbon dioxide (CO2) insufflation.
Other intervention name(s): carbon dioxide (CO2) insufflation
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Diagnostic
Keywords: water-aided colonoscopy; difficult colonoscopy