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Small-bowel aspiration during upper esophagogastroduodenoscopy: Rao technique

Open AccessPublished:December 18, 2020DOI:https://doi.org/10.1016/j.vgie.2020.11.008

      Abbreviations:

      SIBO (small-intestinal bacterial overgrowth), SIFO (small-intestinal fungal overgrowth)
      Small-intestinal bacterial overgrowth (SIBO) and small-intestinal fungal overgrowth (SIFO) are characterized by high levels of bacteria or fungal organisms in the small intestine and are associated with GI symptoms such as bloating, abdominal distention, flatulence, abdominal discomfort, diarrhea, and weight loss. Diagnosis of SIBO and SIFO remain challenging. Although breath testing is noninvasive and used in clinical practice, its sensitivity and specificity remain poorly defined. Small-bowel aspiration and culture during upper endoscopy is generally regarded as the best method for the diagnosis of SIBO and SIFO. However, the optimal technique for aspiration and culture is often debated. In this video manuscript, we describe the Rao technique for small-bowel aspiration during an upper endoscopy.

      Introduction

      Intestinal dysbiosis is increasingly recognized as a common cause of GI symptoms.
      • Saffouri G.B.
      • Shields-Cutler R.R.
      • Chen J.
      • et al.
      Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders.
      The adult GI tract has nearly 38 trillion bacteria, mostly in the colon.
      • Sender R.
      • Fuchs S.
      • Milo R.
      Revised estimates for the number of human and bacteria cells in the body.
      There are very few bacteria in the normal small bowel; if present in sufficient concentrations, however, bacteria can cause symptoms.
      • Rao S.S.C.
      • Rehman A.
      • Yu S.
      • et al.
      Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.
      • Pimentel M.
      • Chow E.J.
      • Lin H.C.
      Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome.
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      Because of the variability in patient populations and methods used to establish a diagnosis,
      • Rezaie A.
      • Buresi M.
      • Lembo A.
      • et al.
      Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
      ,
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.
      SIBO prevalence has been difficult to estimate. SIBO is defined as the presence of an abnormal number of bacteria in the small intestine, together with symptoms of flatulence, bloating, distension, and other unexplained symptoms such as diarrhea, abdominal pain, dyspepsia, and constipation.
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      SIFO is defined as the presence of excess fungal organisms in the small bowel, together with the aforementioned unexplained GI symptoms.
      • Erdogan A.
      • Rao S.S.
      Small intestinal fungal overgrowth.
      The diagnosis of SIBO and SIFO has been challenging because patients with either positive or negative duodenal aspirate and/or breath testing report similar symptoms (ie, symptoms alone are poor predictors of SIBO).
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.
      Consequently, SIBO diagnosis requires specialized testing (Table 1). Glucose breath test and lactulose breath test are generally used. However, the equipment for breath testing is not widely available, the amount of sugar substrates is controversial, and the test interpretation is not standardized and requires further validation.
      • Rao S.S.C.
      • Rehman A.
      • Yu S.
      • et al.
      Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.
      • Pimentel M.
      • Chow E.J.
      • Lin H.C.
      Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome.
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      A recent North American consensus provided some useful recommendations.
      • Rezaie A.
      • Buresi M.
      • Lembo A.
      • et al.
      Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
      Table 1Small-bowel aspiration for SIBO
      Diagnostic testProcedureTesting protocolTest interpretationDiagnostic performanceLimitations
      Duodenal aspirate and culture
      • Rezaie A.
      • Buresi M.
      • Lembo A.
      • et al.
      Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
      ,
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.
      Upper endoscopy performed to obtain samples from distal second or third portions of duodenum
      • 3 mL of duodenal fluid aspirated using aseptic technique (eg, sterile gloves);
      • sample sent to microbiology laboratory immediately after collection for aerobic, anerobic, and fungal cultures
      • Positive test:
      • ≥103 cfu/mL (65.5% agreement between glucose breath test and duodenal aspirate/culture)
      Currently widely accepted as the best diagnostic method for SIBOTesting is invasive, time intensive, and expensive
      SIBO, Small-intestinal bacterial overgrowth.
      Today, most experts agree and the recent American College of Gastroenterology guidelines further endorsed that small-bowel aspiration is currently the best technique for identifying SIBO, although its limitations include invasiveness, cost, lack of standardization of aspiration and microbiological techniques, and need for collaboration with the microbiology laboratory. Here, we describe our technique of small-bowel aspiration to bridge the knowledge gap so that more endoscopists can adopt this technology and facilitate a proper diagnosis of SIBO.

      Endoscopic method of small-bowel aspiration

      In addition to a standard upper endoscope, the equipment needed for this procedure consists of a 6F Liguory catheter (COOK Medical, Bloomington, Ind, USA) with multiple side holes at its tip, sterile gloves, sterile cap, and a 5-mL sterile syringe (Fig. 1 and Video 1, available online at www.VideoGIE.org). The catheter assembly is first prepared while sterile gloves are worn. Next, a disinfected upper endoscope is passed into the distal second or third portions of the duodenum, using minimal air insufflation. Care is taken to avoid aspiration of oral or gastric secretions before the catheter is passed and to avoid other manipulations, such as taking a biopsy sample. The endoscopist and assistant then change into sterile gloves to prevent cross contamination. The endoscopist passes the Liguory catheter through the biopsy channel of the endoscope. The assistant usually sits (Fig. 2) for gravity-assisted suction and uses a 5-mL sterile syringe connected to a 3-way stopcock to gently and repeatedly aspirate the fluid. If the lumen is dry, the liver may be gently massaged to facilitate bile flow. Usually, in 2 to 5 minutes, about 3 mL of bile-stained juice is aspirated.
      • Rao S.S.C.
      • Tan G.
      • Abdulla H.
      • et al.
      Does colectomy predispose to small intestinal bacterial (SIBO) and fungal overgrowth (SIFO)?.
      The duodenal aspirate is immediately sent to the microbiology laboratory for standard aerobic, anaerobic, and fungal cultures.
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.
      ,
      • Erdogan A.
      • Rao S.S.
      Small intestinal fungal overgrowth.
      ,
      • Jacobs C.
      • Coss Adame E.
      • Attaluri A.
      • et al.
      Dysmotility and proton pump inhibitor use are independent risk factors for small intestinal bacterial and/or fungal overgrowth.
      Figure thumbnail gr1
      Figure 1The equipment needed for the duodenal aspiration procedure includes a 6F Liguory catheter with multiple side holes at its tip, sterile gloves, sterile cap, a 5-mL sterile syringe, and a biohazard bag to transport the syringe with aspirate to the microbiology laboratory.
      Figure thumbnail gr2
      Figure 2Description of duodenal aspirate collection and handling. The technician flushes the endoscope with sterile water and prepares a sterile field. The endoscope is passed into the second/third portion of the duodenum with minimal air insufflation and suctioning. The endoscopist and the technician wear sterile gloves. The Liguory catheter is advanced through the biopsy channel. The technician holds the syringe lower than the patient to aid sample flow by gravity. Gentle suction is used to aspirate ∼3 mL of duodenal fluid; this is immediately sent to the microbiology laboratory for bacterial count and cultures.
      Other techniques include a double-lumen aspiration tube, which is not commercially available in the United States
      • Ghoshal U.C.
      • Srivastava D.
      • Ghoshal U.
      • et al.
      Breath tests in the diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome in comparison with quantitative upper gut aspirate culture.
      ; duodenal aspiration through the endoscope, which has a significant risk of cross contamination and false positive results; and a novel oral diagnostic capsule, the Smart Capsule Bacterial Detection System, which merits validation.
      • Singh S.
      • Allan N.
      • Wahl C.
      • et al.
      Development of a swallowable diganostic capsule to monitor gastrointestinal health [abstract].
      A bacterial colony count threshold of ≥103 colony-forming units/mL is recommended by most experts and by recent American College of Gastroenterology guidelines as diagnostic for SIBO when using duodenal aspiration,
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      ,
      • Rezaie A.
      • Buresi M.
      • Lembo A.
      • et al.
      Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
      ,
      • Pimentel M.
      • Saad R.J.
      • Long M.D.
      • et al.
      ACG clinical guideline: small intestinal bacterial overgrowth.
      although some investigators have suggested a higher threshold of ≥105 colony-forming units/mL, based on traditional microbiological standards for bacterial infection and for jejunal culture.
      • Ghoshal U.C.
      • Srivastava D.
      • Ghoshal U.
      • et al.
      Breath tests in the diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome in comparison with quantitative upper gut aspirate culture.
      ,
      • Ghoshal U.C.
      • Ghoshal U.
      Small intestinal bacterial overgrowth and other intestinal disorders.
      • Posserud I.
      • Stotzer P.O.
      • Björnsson E.S.
      • et al.
      Small intestinal bacterial overgrowth in patients with irritable bowel syndrome.
      • Pyleris E.
      • Giamarellos-Bourboulis E.J.
      • Tzivras D.
      • et al.
      The prevalence of overgrowth by aerobic bacteria in the small intestine by small bowel culture: relationship with irritable bowel syndrome.
      • Ghoshal U.C.
      • Srivastava D.
      • Misra A.
      • et al.
      A proof-of-concept study showing antibiotics to be more effective in irritable bowel syndrome with than without small-intestinal bacterial overgrowth: a randomized, double-blind, placebo-controlled trial.

      Indications/contraindications

      The common indications for small-bowel aspiration/culture include persistent flatulence, abdominal bloating, distension, pain, excessive belching without GERD, chronic diarrhea with malabsorption, constipation, and suspected SIBO or SIFO, especially in patients with previous gastric or small intestinal or colonic surgery, connective tissue disorders such as scleroderma or Ehlers-Danlos syndrome, diabetic neuropathy, and gastroparesis. The usual contraindications are those related to high-risk endoscopy and patients who have taken antibiotics in the past 4 to 6 weeks.
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      ,
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.

      Clinical implications

      Small-bowel aspiration and culture currently provides the most accurate method of detecting the presence of aerobic, anerobic, and fungal organisms. This information not only aids diagnosis of SIBO or SIFO but also provides a reasonable estimate of the severity of colonization by the organisms, considering that the duodenum is normally sterile, given its close proximity to the acidic stomach, and because of robust motility. Furthermore, the microbiology culture/sensitivity analysis can guide optimal management with appropriate antibiotics.
      • Rao S.S.C.
      • Bhagatwala J.
      Small intestinal bacterial overgrowth: clinical features and therapeutic management.
      ,
      • Bhagatwala J.
      • Rao S.S.
      Small intestinal bacterial and fungal overgrowth.
      The limitations of small-bowel culture include its invasive nature, cost, potential inability to detect bacterial strains that are difficult to grow under standard culture conditions, detection of proximal SIBO only, and potential for sample contamination.
      • Rezaie A.
      • Buresi M.
      • Lembo A.
      • et al.
      Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
      ,
      • Erdogan A.
      • Rao S.S.
      • Gulley D.
      • et al.
      Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.

      Summary

      SIBO and SIFO are increasingly recognized as common causes of unexplained abdominal bloating, gas, distension, belching, and diarrhea. However, they are poorly recognized because of a lack of standardized diagnostic methods. Although noninvasive breath tests are often used as the first step in SIBO diagnosis, they either lack sensitivity or specificity and require further standardization and validation. Small-bowel aspirate/culture is generally accepted as the best diagnostic method, but it is invasive and is performed if symptoms are recurrent or refectory. Importantly, there is inadequate knowledge regarding the tools needed, the use of aseptic technique, and a standardized technique for collecting the small-bowel juice. Here, we describe our method of performing small-bowel aspiration to facilitate an optimal diagnosis of SIBO or SIFO (Video 1).

      Disclosures

      All authors disclosed no financial relationships.

      Supplementary data

      References

        • Saffouri G.B.
        • Shields-Cutler R.R.
        • Chen J.
        • et al.
        Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders.
        Nat Commun. 2019; 10: 2012
        • Sender R.
        • Fuchs S.
        • Milo R.
        Revised estimates for the number of human and bacteria cells in the body.
        PLoS Biol. 2016; 14e1002533
        • Rao S.S.C.
        • Rehman A.
        • Yu S.
        • et al.
        Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.
        Clin Transl Gastroenterol. 2018; 9: 162
        • Pimentel M.
        • Chow E.J.
        • Lin H.C.
        Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome.
        Am J Gastroenterol. 2000; 95: 3503-3506
        • Rao S.S.C.
        • Bhagatwala J.
        Small intestinal bacterial overgrowth: clinical features and therapeutic management.
        Clin Transl Gastroenterol. 2019; 10: e00078
        • Rezaie A.
        • Buresi M.
        • Lembo A.
        • et al.
        Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus.
        Am J Gastroenterol. 2017; 112: 775-784
        • Erdogan A.
        • Rao S.S.
        • Gulley D.
        • et al.
        Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test.
        Neurogastroenterol Motil. 2015; 27: 481-489
        • Erdogan A.
        • Rao S.S.
        Small intestinal fungal overgrowth.
        Curr Gastroenterol Rep. 2015; 17: 16
        • Rao S.S.C.
        • Tan G.
        • Abdulla H.
        • et al.
        Does colectomy predispose to small intestinal bacterial (SIBO) and fungal overgrowth (SIFO)?.
        Clin Transl Gastroenterol. 2018; 9: 146
        • Jacobs C.
        • Coss Adame E.
        • Attaluri A.
        • et al.
        Dysmotility and proton pump inhibitor use are independent risk factors for small intestinal bacterial and/or fungal overgrowth.
        Aliment Pharmacol Ther. 2013; 37: 1103-1111
        • Ghoshal U.C.
        • Srivastava D.
        • Ghoshal U.
        • et al.
        Breath tests in the diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome in comparison with quantitative upper gut aspirate culture.
        Eur J Gastroenterol Hepatol. 2014; 26: 753-760
        • Singh S.
        • Allan N.
        • Wahl C.
        • et al.
        Development of a swallowable diganostic capsule to monitor gastrointestinal health [abstract].
        Gastroenterology. 2019; 156: Sa1717
        • Pimentel M.
        • Saad R.J.
        • Long M.D.
        • et al.
        ACG clinical guideline: small intestinal bacterial overgrowth.
        Am J Gastroenterol. 2020; 115: 165-178
        • Ghoshal U.C.
        • Ghoshal U.
        Small intestinal bacterial overgrowth and other intestinal disorders.
        Gastroenterol Clin North Am. 2017; 46: 103-120
        • Posserud I.
        • Stotzer P.O.
        • Björnsson E.S.
        • et al.
        Small intestinal bacterial overgrowth in patients with irritable bowel syndrome.
        Gut. 2007; 56: 802-808
        • Pyleris E.
        • Giamarellos-Bourboulis E.J.
        • Tzivras D.
        • et al.
        The prevalence of overgrowth by aerobic bacteria in the small intestine by small bowel culture: relationship with irritable bowel syndrome.
        Dig Dis Sci. 2012; 57: 1321-1329
        • Ghoshal U.C.
        • Srivastava D.
        • Misra A.
        • et al.
        A proof-of-concept study showing antibiotics to be more effective in irritable bowel syndrome with than without small-intestinal bacterial overgrowth: a randomized, double-blind, placebo-controlled trial.
        Eur J Gastroenterol Hepatol. 2016; 28: 281-289
        • Bhagatwala J.
        • Rao S.S.
        Small intestinal bacterial and fungal overgrowth.
        in: Rao S.S.C. Lee Y.Y. Ghoshal U. Clinical and Basic Neurogastroenterology and Motility. Elsevier, Amsterdam, Netherlands2020: 343-358