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Explosion From Argon Cautery During Proctoileoscopy of a Patient With a Colectomy

2012; Elsevier BV; Volume: 10; Issue: 10 Linguagem: Inglês

10.1016/j.cgh.2012.06.004

1542-7714

Otto S. Lin, Thomas Biehl, Geoffrey C. Jiranek, Richard A. Kozarek,

Biliary and Gastrointestinal Fistulas

We report a unique case of a 70-year-old woman with Gardner's syndrome who had a subtotal colectomy with ileoproctostomy. Since then, she has undergone 12 uncomplicated proctoileoscopies, each time with argon plasma coagulation ablation of small polyps without any bowel preparation. However, during the most recent procedure, when we attempted to cauterize some rectal polyps, an immediate explosion occurred, leading to multiple rectal and ileal perforations that required surgical repair with a temporary end ileostomy. This event suggests that bacterial fermentation of colonic content or visible feces is not necessary for combustion because we observed a cautery-related explosion in the absence of a colon. This case shows the need for adequate bowel preparation if cautery is to be used, even in patients who have undergone a colectomy. We report a unique case of a 70-year-old woman with Gardner's syndrome who had a subtotal colectomy with ileoproctostomy. Since then, she has undergone 12 uncomplicated proctoileoscopies, each time with argon plasma coagulation ablation of small polyps without any bowel preparation. However, during the most recent procedure, when we attempted to cauterize some rectal polyps, an immediate explosion occurred, leading to multiple rectal and ileal perforations that required surgical repair with a temporary end ileostomy. This event suggests that bacterial fermentation of colonic content or visible feces is not necessary for combustion because we observed a cautery-related explosion in the absence of a colon. This case shows the need for adequate bowel preparation if cautery is to be used, even in patients who have undergone a colectomy. Cautery-related explosion during colonoscopy or sigmoidoscopy caused by accumulation of methane/hydrogen produced by bacteria has been well documented (Supplementary Table 1).1Manner H. Plum N. Pech O. et al.Colon explosion during argon plasma coagulation.Gastrointest Endosc. 2008; 67: 1123-1127Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar Here, we report an unusual case of explosion associated with argon plasma coagulation during proctoileoscopy in a patient who had undergone previous subtotal colectomy.Case ReportWe report the case of a 70-year-old woman with Gardner's syndrome who had a previous history of sigmoid cancer; numerous adenomas of the colon, rectum, ileum, stomach, and duodenum; as well as extraintestinal manifestations such as skin lesions and dental abnormalities. She had a subtotal colectomy with ileoproctostomy 40 years ago, and since then has undergone regular endoscopic surveillance. Over the past 2 decades, she has undergone 12 prior uncomplicated proctoileoscopies, each time with argon plasma coagulation ablation of small rectal and ileal polyps without bowel preparation.During the current proctoileoscopy, rectal polyps were again discovered. Because she had no colon and her previous procedures had been uncomplicated, she had not had any bowel preparation; nevertheless, the rectum and ileum were noted to be clean with almost no residual stool (Supplementary Figure 1). A large 1.2-cm pedunculated rectal adenoma was removed by snare polypectomy with cautery without incident. Argon plasma coagulation then was used to ablate 3 diminutive polyps in the rectum, with the following settings: pulse sequence, flow of 0.8 L/min, and power of 60 W (device manufactured by ERBE, Inc, Marietta, GA). Room air was used for insufflation. The first 2 pulses were uneventful, but upon application of the third pulse, there was an audible explosion and the colonoscope was expelled forcefully from the rectum accompanied by a visible blue flame out of the anus. After the explosion, the patient had abdominal pain, hematochezia, and was hypotensive, but responded hemodynamically within 3 minutes to fluid resuscitation alone. An abdominal radiograph showed extensive free intraperitoneal air, and the patient underwent an emergency laparotomy, where she was found to have a proximal rectal perforation at 15 cm from the anal verge and 4 ileal perforations of various sizes within 30 cm of the ileorectal anastomosis (Figure 1). These injuries were managed surgically with a limited ileal resection, repair of the rectal perforation, and an end ileostomy. She recovered, and 2 months later her ileostomy was taken down and she returned to her usual bowel function. A lactulose hydrogen breath test performed 2 months after the explosion did not show bacterial overgrowth.DiscussionFor intracolonic combustion to occur, the minimal gas thresholds are estimated to be 4% (40,000 ppm) for hydrogen and 4.4% (44,000 ppm) for methane.1Manner H. Plum N. Pech O. et al.Colon explosion during argon plasma coagulation.Gastrointest Endosc. 2008; 67: 1123-1127Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar Human flatus can contain up to 44% hydrogen and 30% methane,2Kirk E. The quantity and composition of human colonic flatus.Gastroenterology. 1949; 12: 782-794Abstract Full Text PDF PubMed Scopus (64) Google Scholar thus it is clear that combustion can occur in unprepared or partially prepared colons.3Ben-Soussan E. Antonietti M. Savoye G. et al.Argon plasma coagulation in the treatment of hemorrhagic radiation proctitis is efficient but requires a perfect colonic cleansing to be safe.Eur J Gastroenterol Hepatol. 2004; 16: 1315-1318Crossref PubMed Scopus (59) Google Scholar, 4Pichon N. Maisonnette F. Cessot F. et al.Colonic perforations after gas explosion induced by argon plasma coagulation.Endoscopy. 2004; 36: 573Crossref PubMed Scopus (0) Google Scholar However, even in patients having undergone full preparation, an explosion can still potentially occur; agents such as sorbitol,5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar, 6Rerknimitr R. Sorbitol can be the cause of colonic explosion.Endoscopy. 2007; 39: 257Crossref PubMed Scopus (5) Google Scholar mannitol,7Bigard M.A. Gaucher P. Lassalle C. Fatal colonic explosion during colonoscopic polypectomy.Gastroenterology. 1979; 77: 1307-1310Abstract Full Text PDF PubMed Google Scholar and macrogol (polyethylene glycol)8Nürnberg D. Pannwitz H. Burkhardt K.D. et al.Gas explosion caused by argon plasma coagulation of colonic angiodysplasias.Endoscopy. 2007; 39: E182Crossref PubMed Scopus (0) Google Scholar all have been implicated. Most cases are thought to be caused by the presence of retained stool in the colon, but the degree of cleanliness may constitute only one of the factors in the explosion risk. Explosions have been reported in “clean” colons5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar; in such cases, bacterial fermentation of carbohydrate-based cleansing substrates is believed to produce combustible gas mixtures.Several studies have prospectively assessed intracolonic hydrogen and methane levels after bowel preparation with various agents. The 2 relevant variables are the type of preparation agent used and whether the colon was insufflated with room air before a gas sample was taken. Intracolonic gas levels without air insufflation sometimes show high levels of hydrogen or methane after bowel preparation with certain agents. For example, mannitol is no longer used because studies have shown high postpreparation levels of intracolonic hydrogen or methane.9Taylor E.W. Bentley S. Youngs D. et al.Bowel preparation and the safety of colonoscopic polypectomy.Gastroenterology. 1981; 81: 1-4Abstract Full Text PDF PubMed Scopus (54) Google Scholar, 10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 12Beck D.E. Fazio V.W. Jagelman D.G. Comparison of oral lavage methods for preoperative colonic cleansing.Dis Colon Rectum. 1986; 29: 699-703Crossref PubMed Scopus (48) Google Scholar On the other hand, if intracolonic gas samples are measured after air insufflation, in most cases patients did not have increased hydrogen or methane levels, no matter which bowel preparation agent was used.10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 13Trotman I. Walt R. Mannitol and explosions.Lancet. 1981; 1: 848Abstract PubMed Google Scholar, 14Strocchi A. Bond J.H. Ellis C. et al.Colonic concentrations of hydrogen and methane following colonoscopic preparation with an oral lavage solution.Gastrointest Endosc. 1990; 36: 580-582Abstract Full Text PDF PubMed Scopus (27) Google Scholar, 15Monahan D.W. Peluso F.E. Goldner F. Combustible colonic gas levels during flexible sigmoidoscopy and colonoscopy.Gastrointest Endosc. 1992; 38: 40-43Abstract Full Text PDF PubMed Scopus (36) Google Scholar Studies that used breath analysis to measure expired gas levels (a surrogate for intracolonic gas levels) generally have not shown high hydrogen or methane levels regardless of the preparation agent used.16DiPalma J.A. Brady 3rd, C.E. Stewart D.L. et al.Comparison of colon cleansing methods in preparation for colonoscopy.Gastroenterology. 1984; 86: 856-860PubMed Google Scholar, 17Bond Jr, J.H. Levitt M.D. Factors affecting the concentration of combustible gases in the colon during colonoscopy.Gastroenterology. 1975; 68: 1445-1448Abstract Full Text PDF PubMed Scopus (55) Google ScholarColonoscopic explosion is a rare, catastrophic event not easily forgotten by those involved. Besides the obvious physical harm to the patient, other potential consequences should be considered. None of the reported cases have described physical harm to the endoscopy staff, probably because such explosions are of limited magnitude and the explosive force is absorbed by the patient's body. After the incident, our colonoscope was checked by the manufacturer (Olympus America, Center Valley, PA) and found to be undamaged. The potential for medicolegal complications after an explosion is a possibility, although it was not a problem in our case because of our longstanding relationship with the patient. In general, the risk of explosion seems to be extremely low, as evidenced by the fact that only 11 previous cases have been published (Supplementary Table 1); therefore, an explicit consent for this possibility may not be necessary for routine colonoscopies.Many of the reported explosions seem to be associated with argon plasma cautery, despite the fact that monopolar coagulation snare polypectomy is undoubtedly much more commonly performed during colonoscopy. It is possible that the heavy weight of argon gas may cause layering, leading to trapped pockets with unusually high concentrations of hydrogen, methane, or oxygen. Argon itself, being an inert gas that sparks when energy is applied, may play a role by providing the initial kindle point.18Ginsberg G.G. Barkun A.N. Bosco J.J. et al.The argon plasma coagulator: February 2002.Gastrointest Endosc. 2002; 55: 807-810Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar In the past, we had successfully used argon cautery in patients with polyposis syndromes because it is a much more efficient technique than using biopsy forceps or polypectomy snare when confronted with large numbers of diminutive polyps that need to be ablated. Bowel preparation was not believed to be necessary in this particular case because the patient had no colon and, indeed, during 12 previous ileoproctoscopies argon cautery had been used for ablation of tiny polyps without any complications. However, our patient still retained her rectum, which may function as a colon in terms of possibly serving as the site for bacteria overgrowth or accumulation of hydrogen/methane. Although the rectum has a much smaller capacity than the colon, combustion potential depends on the concentration and not the volume of hydrogen or methane present.After this incident, we have changed our practice to include full bowel preparation for all cases of argon cautery during colonoscopy, sigmoidoscopy, or ileoscopy. This case adds to the literature supporting the need for bowel preparation in all circumstances in which cautery is to be used, even in patients who have undergone colectomy previously. Cautery-related explosion during colonoscopy or sigmoidoscopy caused by accumulation of methane/hydrogen produced by bacteria has been well documented (Supplementary Table 1).1Manner H. Plum N. Pech O. et al.Colon explosion during argon plasma coagulation.Gastrointest Endosc. 2008; 67: 1123-1127Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar Here, we report an unusual case of explosion associated with argon plasma coagulation during proctoileoscopy in a patient who had undergone previous subtotal colectomy. Case ReportWe report the case of a 70-year-old woman with Gardner's syndrome who had a previous history of sigmoid cancer; numerous adenomas of the colon, rectum, ileum, stomach, and duodenum; as well as extraintestinal manifestations such as skin lesions and dental abnormalities. She had a subtotal colectomy with ileoproctostomy 40 years ago, and since then has undergone regular endoscopic surveillance. Over the past 2 decades, she has undergone 12 prior uncomplicated proctoileoscopies, each time with argon plasma coagulation ablation of small rectal and ileal polyps without bowel preparation.During the current proctoileoscopy, rectal polyps were again discovered. Because she had no colon and her previous procedures had been uncomplicated, she had not had any bowel preparation; nevertheless, the rectum and ileum were noted to be clean with almost no residual stool (Supplementary Figure 1). A large 1.2-cm pedunculated rectal adenoma was removed by snare polypectomy with cautery without incident. Argon plasma coagulation then was used to ablate 3 diminutive polyps in the rectum, with the following settings: pulse sequence, flow of 0.8 L/min, and power of 60 W (device manufactured by ERBE, Inc, Marietta, GA). Room air was used for insufflation. The first 2 pulses were uneventful, but upon application of the third pulse, there was an audible explosion and the colonoscope was expelled forcefully from the rectum accompanied by a visible blue flame out of the anus. After the explosion, the patient had abdominal pain, hematochezia, and was hypotensive, but responded hemodynamically within 3 minutes to fluid resuscitation alone. An abdominal radiograph showed extensive free intraperitoneal air, and the patient underwent an emergency laparotomy, where she was found to have a proximal rectal perforation at 15 cm from the anal verge and 4 ileal perforations of various sizes within 30 cm of the ileorectal anastomosis (Figure 1). These injuries were managed surgically with a limited ileal resection, repair of the rectal perforation, and an end ileostomy. She recovered, and 2 months later her ileostomy was taken down and she returned to her usual bowel function. A lactulose hydrogen breath test performed 2 months after the explosion did not show bacterial overgrowth. We report the case of a 70-year-old woman with Gardner's syndrome who had a previous history of sigmoid cancer; numerous adenomas of the colon, rectum, ileum, stomach, and duodenum; as well as extraintestinal manifestations such as skin lesions and dental abnormalities. She had a subtotal colectomy with ileoproctostomy 40 years ago, and since then has undergone regular endoscopic surveillance. Over the past 2 decades, she has undergone 12 prior uncomplicated proctoileoscopies, each time with argon plasma coagulation ablation of small rectal and ileal polyps without bowel preparation. During the current proctoileoscopy, rectal polyps were again discovered. Because she had no colon and her previous procedures had been uncomplicated, she had not had any bowel preparation; nevertheless, the rectum and ileum were noted to be clean with almost no residual stool (Supplementary Figure 1). A large 1.2-cm pedunculated rectal adenoma was removed by snare polypectomy with cautery without incident. Argon plasma coagulation then was used to ablate 3 diminutive polyps in the rectum, with the following settings: pulse sequence, flow of 0.8 L/min, and power of 60 W (device manufactured by ERBE, Inc, Marietta, GA). Room air was used for insufflation. The first 2 pulses were uneventful, but upon application of the third pulse, there was an audible explosion and the colonoscope was expelled forcefully from the rectum accompanied by a visible blue flame out of the anus. After the explosion, the patient had abdominal pain, hematochezia, and was hypotensive, but responded hemodynamically within 3 minutes to fluid resuscitation alone. An abdominal radiograph showed extensive free intraperitoneal air, and the patient underwent an emergency laparotomy, where she was found to have a proximal rectal perforation at 15 cm from the anal verge and 4 ileal perforations of various sizes within 30 cm of the ileorectal anastomosis (Figure 1). These injuries were managed surgically with a limited ileal resection, repair of the rectal perforation, and an end ileostomy. She recovered, and 2 months later her ileostomy was taken down and she returned to her usual bowel function. A lactulose hydrogen breath test performed 2 months after the explosion did not show bacterial overgrowth. DiscussionFor intracolonic combustion to occur, the minimal gas thresholds are estimated to be 4% (40,000 ppm) for hydrogen and 4.4% (44,000 ppm) for methane.1Manner H. Plum N. Pech O. et al.Colon explosion during argon plasma coagulation.Gastrointest Endosc. 2008; 67: 1123-1127Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar Human flatus can contain up to 44% hydrogen and 30% methane,2Kirk E. The quantity and composition of human colonic flatus.Gastroenterology. 1949; 12: 782-794Abstract Full Text PDF PubMed Scopus (64) Google Scholar thus it is clear that combustion can occur in unprepared or partially prepared colons.3Ben-Soussan E. Antonietti M. Savoye G. et al.Argon plasma coagulation in the treatment of hemorrhagic radiation proctitis is efficient but requires a perfect colonic cleansing to be safe.Eur J Gastroenterol Hepatol. 2004; 16: 1315-1318Crossref PubMed Scopus (59) Google Scholar, 4Pichon N. Maisonnette F. Cessot F. et al.Colonic perforations after gas explosion induced by argon plasma coagulation.Endoscopy. 2004; 36: 573Crossref PubMed Scopus (0) Google Scholar However, even in patients having undergone full preparation, an explosion can still potentially occur; agents such as sorbitol,5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar, 6Rerknimitr R. Sorbitol can be the cause of colonic explosion.Endoscopy. 2007; 39: 257Crossref PubMed Scopus (5) Google Scholar mannitol,7Bigard M.A. Gaucher P. Lassalle C. Fatal colonic explosion during colonoscopic polypectomy.Gastroenterology. 1979; 77: 1307-1310Abstract Full Text PDF PubMed Google Scholar and macrogol (polyethylene glycol)8Nürnberg D. Pannwitz H. Burkhardt K.D. et al.Gas explosion caused by argon plasma coagulation of colonic angiodysplasias.Endoscopy. 2007; 39: E182Crossref PubMed Scopus (0) Google Scholar all have been implicated. Most cases are thought to be caused by the presence of retained stool in the colon, but the degree of cleanliness may constitute only one of the factors in the explosion risk. Explosions have been reported in “clean” colons5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar; in such cases, bacterial fermentation of carbohydrate-based cleansing substrates is believed to produce combustible gas mixtures.Several studies have prospectively assessed intracolonic hydrogen and methane levels after bowel preparation with various agents. The 2 relevant variables are the type of preparation agent used and whether the colon was insufflated with room air before a gas sample was taken. Intracolonic gas levels without air insufflation sometimes show high levels of hydrogen or methane after bowel preparation with certain agents. For example, mannitol is no longer used because studies have shown high postpreparation levels of intracolonic hydrogen or methane.9Taylor E.W. Bentley S. Youngs D. et al.Bowel preparation and the safety of colonoscopic polypectomy.Gastroenterology. 1981; 81: 1-4Abstract Full Text PDF PubMed Scopus (54) Google Scholar, 10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 12Beck D.E. Fazio V.W. Jagelman D.G. Comparison of oral lavage methods for preoperative colonic cleansing.Dis Colon Rectum. 1986; 29: 699-703Crossref PubMed Scopus (48) Google Scholar On the other hand, if intracolonic gas samples are measured after air insufflation, in most cases patients did not have increased hydrogen or methane levels, no matter which bowel preparation agent was used.10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 13Trotman I. Walt R. Mannitol and explosions.Lancet. 1981; 1: 848Abstract PubMed Google Scholar, 14Strocchi A. Bond J.H. Ellis C. et al.Colonic concentrations of hydrogen and methane following colonoscopic preparation with an oral lavage solution.Gastrointest Endosc. 1990; 36: 580-582Abstract Full Text PDF PubMed Scopus (27) Google Scholar, 15Monahan D.W. Peluso F.E. Goldner F. Combustible colonic gas levels during flexible sigmoidoscopy and colonoscopy.Gastrointest Endosc. 1992; 38: 40-43Abstract Full Text PDF PubMed Scopus (36) Google Scholar Studies that used breath analysis to measure expired gas levels (a surrogate for intracolonic gas levels) generally have not shown high hydrogen or methane levels regardless of the preparation agent used.16DiPalma J.A. Brady 3rd, C.E. Stewart D.L. et al.Comparison of colon cleansing methods in preparation for colonoscopy.Gastroenterology. 1984; 86: 856-860PubMed Google Scholar, 17Bond Jr, J.H. Levitt M.D. Factors affecting the concentration of combustible gases in the colon during colonoscopy.Gastroenterology. 1975; 68: 1445-1448Abstract Full Text PDF PubMed Scopus (55) Google ScholarColonoscopic explosion is a rare, catastrophic event not easily forgotten by those involved. Besides the obvious physical harm to the patient, other potential consequences should be considered. None of the reported cases have described physical harm to the endoscopy staff, probably because such explosions are of limited magnitude and the explosive force is absorbed by the patient's body. After the incident, our colonoscope was checked by the manufacturer (Olympus America, Center Valley, PA) and found to be undamaged. The potential for medicolegal complications after an explosion is a possibility, although it was not a problem in our case because of our longstanding relationship with the patient. In general, the risk of explosion seems to be extremely low, as evidenced by the fact that only 11 previous cases have been published (Supplementary Table 1); therefore, an explicit consent for this possibility may not be necessary for routine colonoscopies.Many of the reported explosions seem to be associated with argon plasma cautery, despite the fact that monopolar coagulation snare polypectomy is undoubtedly much more commonly performed during colonoscopy. It is possible that the heavy weight of argon gas may cause layering, leading to trapped pockets with unusually high concentrations of hydrogen, methane, or oxygen. Argon itself, being an inert gas that sparks when energy is applied, may play a role by providing the initial kindle point.18Ginsberg G.G. Barkun A.N. Bosco J.J. et al.The argon plasma coagulator: February 2002.Gastrointest Endosc. 2002; 55: 807-810Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar In the past, we had successfully used argon cautery in patients with polyposis syndromes because it is a much more efficient technique than using biopsy forceps or polypectomy snare when confronted with large numbers of diminutive polyps that need to be ablated. Bowel preparation was not believed to be necessary in this particular case because the patient had no colon and, indeed, during 12 previous ileoproctoscopies argon cautery had been used for ablation of tiny polyps without any complications. However, our patient still retained her rectum, which may function as a colon in terms of possibly serving as the site for bacteria overgrowth or accumulation of hydrogen/methane. Although the rectum has a much smaller capacity than the colon, combustion potential depends on the concentration and not the volume of hydrogen or methane present.After this incident, we have changed our practice to include full bowel preparation for all cases of argon cautery during colonoscopy, sigmoidoscopy, or ileoscopy. This case adds to the literature supporting the need for bowel preparation in all circumstances in which cautery is to be used, even in patients who have undergone colectomy previously. For intracolonic combustion to occur, the minimal gas thresholds are estimated to be 4% (40,000 ppm) for hydrogen and 4.4% (44,000 ppm) for methane.1Manner H. Plum N. Pech O. et al.Colon explosion during argon plasma coagulation.Gastrointest Endosc. 2008; 67: 1123-1127Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar Human flatus can contain up to 44% hydrogen and 30% methane,2Kirk E. The quantity and composition of human colonic flatus.Gastroenterology. 1949; 12: 782-794Abstract Full Text PDF PubMed Scopus (64) Google Scholar thus it is clear that combustion can occur in unprepared or partially prepared colons.3Ben-Soussan E. Antonietti M. Savoye G. et al.Argon plasma coagulation in the treatment of hemorrhagic radiation proctitis is efficient but requires a perfect colonic cleansing to be safe.Eur J Gastroenterol Hepatol. 2004; 16: 1315-1318Crossref PubMed Scopus (59) Google Scholar, 4Pichon N. Maisonnette F. Cessot F. et al.Colonic perforations after gas explosion induced by argon plasma coagulation.Endoscopy. 2004; 36: 573Crossref PubMed Scopus (0) Google Scholar However, even in patients having undergone full preparation, an explosion can still potentially occur; agents such as sorbitol,5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar, 6Rerknimitr R. Sorbitol can be the cause of colonic explosion.Endoscopy. 2007; 39: 257Crossref PubMed Scopus (5) Google Scholar mannitol,7Bigard M.A. Gaucher P. Lassalle C. Fatal colonic explosion during colonoscopic polypectomy.Gastroenterology. 1979; 77: 1307-1310Abstract Full Text PDF PubMed Google Scholar and macrogol (polyethylene glycol)8Nürnberg D. Pannwitz H. Burkhardt K.D. et al.Gas explosion caused by argon plasma coagulation of colonic angiodysplasias.Endoscopy. 2007; 39: E182Crossref PubMed Scopus (0) Google Scholar all have been implicated. Most cases are thought to be caused by the presence of retained stool in the colon, but the degree of cleanliness may constitute only one of the factors in the explosion risk. Explosions have been reported in “clean” colons5Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (17) Google Scholar; in such cases, bacterial fermentation of carbohydrate-based cleansing substrates is believed to produce combustible gas mixtures. Several studies have prospectively assessed intracolonic hydrogen and methane levels after bowel preparation with various agents. The 2 relevant variables are the type of preparation agent used and whether the colon was insufflated with room air before a gas sample was taken. Intracolonic gas levels without air insufflation sometimes show high levels of hydrogen or methane after bowel preparation with certain agents. For example, mannitol is no longer used because studies have shown high postpreparation levels of intracolonic hydrogen or methane.9Taylor E.W. Bentley S. Youngs D. et al.Bowel preparation and the safety of colonoscopic polypectomy.Gastroenterology. 1981; 81: 1-4Abstract Full Text PDF PubMed Scopus (54) Google Scholar, 10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 12Beck D.E. Fazio V.W. Jagelman D.G. Comparison of oral lavage methods for preoperative colonic cleansing.Dis Colon Rectum. 1986; 29: 699-703Crossref PubMed Scopus (48) Google Scholar On the other hand, if intracolonic gas samples are measured after air insufflation, in most cases patients did not have increased hydrogen or methane levels, no matter which bowel preparation agent was used.10La Brooy S.J. Avgerinos A. Fendick C.L. et al.Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol.Lancet. 1981; 1: 634-636Abstract PubMed Scopus (42) Google Scholar, 11Avgerinos A. Kalantzis N. Rekoumis G. et al.Bowel preparation and the risk of explosion during colonoscopic polypectomy.Gut. 1984; 25: 361-364Crossref PubMed Scopus (56) Google Scholar, 13Trotman I. Walt R. Mannitol and explosions.Lancet. 1981; 1: 848Abstract PubMed Google Scholar, 14Strocchi A. Bond J.H. Ellis C. et al.Colonic concentrations of hydrogen and methane following colonoscopic preparation with an oral lavage solution.Gastrointest Endosc. 1990; 36: 580-582Abstract Full Text PDF PubMed Scopus (27) Google Scholar, 15Monahan D.W. Peluso F.E. Goldner F. Combustible colonic gas levels during flexible sigmoidoscopy and colonoscopy.Gastrointest Endosc. 1992; 38: 40-43Abstract Full Text PDF PubMed Scopus (36) Google Scholar Studies that used breath analysis to measure expired gas levels (a surrogate for intracolonic gas levels) generally have not shown high hydrogen or methane levels regardless of the preparation agent used.16DiPalma J.A. Brady 3rd, C.E. Stewart D.L. et al.Comparison of colon cleansing methods in preparation for colonoscopy.Gastroenterology. 1984; 86: 856-860PubMed Google Scholar, 17Bond Jr, J.H. Levitt M.D. Factors affecting the concentration of combustible gases in the colon during colonoscopy.Gastroenterology. 1975; 68: 1445-1448Abstract Full Text PDF PubMed Scopus (55) Google Scholar Colonoscopic explosion is a rare, catastrophic event not easily forgotten by those involved. Besides the obvious physical harm to the patient, other potential consequences should be considered. None of the reported cases have described physical harm to the endoscopy staff, probably because such explosions are of limited magnitude and the explosive force is absorbed by the patient's body. After the incident, our colonoscope was checked by the manufacturer (Olympus America, Center Valley, PA) and found to be undamaged. The potential for medicolegal complications after an explosion is a possibility, although it was not a problem in our case because of our longstanding relationship with the patient. In general, the risk of explosion seems to be extremely low, as evidenced by the fact that only 11 previous cases have been published (Supplementary Table 1); therefore, an explicit consent for this possibility may not be necessary for routine colonoscopies. Many of the reported explosions seem to be associated with argon plasma cautery, despite the fact that monopolar coagulation snare polypectomy is undoubtedly much more commonly performed during colonoscopy. It is possible that the heavy weight of argon gas may cause layering, leading to trapped pockets with unusually high concentrations of hydrogen, methane, or oxygen. Argon itself, being an inert gas that sparks when energy is applied, may play a role by providing the initial kindle point.18Ginsberg G.G. Barkun A.N. Bosco J.J. et al.The argon plasma coagulator: February 2002.Gastrointest Endosc. 2002; 55: 807-810Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar In the past, we had successfully used argon cautery in patients with polyposis syndromes because it is a much more efficient technique than using biopsy forceps or polypectomy snare when confronted with large numbers of diminutive polyps that need to be ablated. Bowel preparation was not believed to be necessary in this particular case because the patient had no colon and, indeed, during 12 previous ileoproctoscopies argon cautery had been used for ablation of tiny polyps without any complications. However, our patient still retained her rectum, which may function as a colon in terms of possibly serving as the site for bacteria overgrowth or accumulation of hydrogen/methane. Although the rectum has a much smaller capacity than the colon, combustion potential depends on the concentration and not the volume of hydrogen or methane present. After this incident, we have changed our practice to include full bowel preparation for all cases of argon cautery during colonoscopy, sigmoidoscopy, or ileoscopy. This case adds to the literature supporting the need for bowel preparation in all circumstances in which cautery is to be used, even in patients who have undergone colectomy previously. The authors would like to thank Jane Babione for her assistance and input. Supplementary materialSupplementary Table 1Previously Published Cases of Endoscopic Explosion Associated With CauteryReportProcedureBowel preparation agentBowel cleanlinessCautery typeConsequencesBond et al,1Bond J.H. Levy M. Levitt M.D. Explosion of hydrogen gas in the colon during proctosigmoidoscopy.Gastrointest Endosc. 1976; 23: 41-42Abstract Full Text PDF PubMed Scopus (23) Google Scholar 1976SigmoidoscopySodium phosphate enema“Thorough cleansing of rectosigmoid area”Monopolar fulgurationPatient survived after surgical suturing of multiple perforationsBigard et al,2Bigard M.A. Gaucher P. Lassalle C. Fatal colonic explosion during colonoscopic polypectomy.Gastroenterology. 1979; 77: 1307-1310Abstract Full Text PDF PubMed Scopus (158) Google Scholar 1979ColonoscopyMannitol“Completely clean”Monopolar snare polypectomyPatient died despite surgery and transfusions for multiple colonic perforationsRaillat et al,3Raillat A. de Saint-Julien J. Abgrall J. [Colonic explosion during an endoscopic electrocoagulation after preparation with mannitol].Gastroenterol Clin Biol. 1982; 6: 301-302PubMed Google Scholar 1982ColonoscopyMannitolNot describedMonopolar snare polypectomyMultiple colonic perforationsZinsser et al,4Zinsser E. Will U. Gottschalk P. et al.Bowel gas explosion during argon plasma coagulation.Endoscopy. 1999; 31: S26Crossref PubMed Scopus (7) Google Scholar 1999SigmoidoscopySodium phosphate enemaNot describedArgon plasma coagulationPatient did not sustain a perforationBen-Soussan et al,5Ben-Soussan E. Mathieu N. Roque I. et al.Bowel explosion with colonic perforation during argon plasma coagulation for hemorrhagic radiation-induced proctitis.Gastrointest Endosc. 2003; 57: 412-413Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar 2003SigmoidoscopySterculia enemas“Solid stool proximal to the lesions”Argon plasma coagulationPatient survived after surgical suturing of multiple perforationsBen-Soussan et al,6Ben-Soussan E. Antonietti M. Savoye G. et al.Argon plasma coagulation in the treatment of hemorrhagic radiation proctitis is efficient but requires a perfect colonic cleansing to be safe.Eur J Gastroenterol Hepatol. 2004; 16: 1315-1318Crossref PubMed Scopus (59) Google Scholar 2004aThis study also described the second case resulting in colonic perforation previously reported by the same investigators in 2003.Sigmoidoscopy (2 audible explosions during successive sessions)EnemasNot describedArgon plasma coagulationPatient did not sustain a perforationPichon et al,7Pichon N. Maisonnette F. Cessot F. et al.Colonic perforations after gas explosion induced by argon plasma coagulation.Endoscopy. 2004; 36: 573Crossref PubMed Scopus (22) Google Scholar 2004ColonoscopySaline enemasNot describedArgon plasma coagulationLaparoscopic suturing of multiple colonic perforationsJosemanders et al,8Josemanders D.F. Spillenaar Bilgen E.J. van Sorge A.A. et al.Colonic explosion during endoscopic polypectomy: avoidable complication or bad luck?.Endoscopy. 2006; 38: 943-944Crossref PubMed Scopus (18) Google Scholar 2006ColonoscopyPolyethylene glycol and sorbitol“Trace fecal matter (<10 mL) … as clean as could be expected”Monopolar snare polypectomySurgery with right hemicolectomy and partial sigmoidectomy for multiple colonic perforationsNürnberg et al,9Nürnberg D. Pannwitz H. Burkhardt K.D. et al.Gas explosion caused by argon plasma coagulation of colonic angiodysplasias.Endoscopy. 2007; 39: E182Crossref PubMed Scopus (13) Google Scholar 2007ColonoscopyPolyethylene glycolNot describedArgon plasma coagulationPatient survived after right hemicolectomyTownshend et al,10Townshend A.P. Goddard W.P. Cid J.A. Bowel perforation requiring emergency laparotomy and a Hartmann's procedure after a gas explosion induced by argon plasma coagulation.Endoscopy. 2007; 39: E1Crossref PubMed Scopus (8) Google Scholar 2007SigmoidoscopySodium phosphate enemaNot describedArgon plasma coagulationPatient survived after partial colectomySeth et al,11Seth A.K. Kapoor N. Puri P. Colonic explosion with use of argon plasma coagulation for radiation proctitis.Indian J Gastroenterol. 2009; 28: 118-119Crossref PubMed Scopus (4) Google Scholar 2009SigmoidoscopyOral sodium phosphate“Liquid stool in rectum”Argon plasma coagulationPatient developed superficial bleeding rectal ulcers but no perforationNOTE. All cases involved the use of room air for insufflation during colonoscopy or sigmoidoscopy.a This study also described the second case resulting in colonic perforation previously reported by the same investigators in 2003. Open table in a new tab NOTE. All cases involved the use of room air for insufflation during colonoscopy or sigmoidoscopy.