EDITORIAL

Performing an ERCP with the patient in the supine position:necessity is the mother of improvisation

Almost 4 decades ago, both Watson,1 who is creditedwith the first published article about ERCP, and Oi,2 whowrote the first article about ERCP in Gastrointestinal Endos-copy, performed the then ‘‘novel’’ procedure of an ERCPwith their patients lying in the left lateral position. However,as ERCP became more established, endoscopists commonlyperformed this procedure with the patients lying in theprone position for ease of visualization and cannulation ofthe ampulla of Vater. Textbooks of GI endoscopy typicallyrecommend that, at the beginning of the procedure, thepatient should be lying on the table with the left arm behindthe back to facilitate subsequent rotation into the proneposition. This is achieved by first placing the patient in theprone position with the head facing right and both armsat the side. The torso is then rotated by bringing the rightleg and right arm into a flexed position and supportingthe patient by placement of a triangular wedge or cylindricalpillow underneath the right side. This modified left lateraldecubitus facilitates esophageal and pyloric intubation,and, as the duodenum is reached, the patient is put intoa prone position by removing the supporting wedge orpillow and extending the right lower extremity.3,4

It is, however, often quite cumbersome and uncomfort-able for certain categories of patients to be in the proneposition. Such patients are those with morbid obesity,advanced pregnancy, gross ascites, and recent abdominalsurgery. Percutaneous drains, such as cholecystostomytubes or transhepatic biliary drainage catheters, are oftendifficult to access in the prone position. Also, in patientswho require deep sedation with endotracheal anesthesia,airway management may become challenging in the proneposition. Biliary endoscopists are often faced with the taskof performing an ERCP either in the left lateral position oreven in the supine position, and it is surprising that, untilrecently, there had been no published data on the impactof patient positioning on the safety and outcomes of anERCP. In this issue of Gastrointestinal Endoscopy, Ferreiraand Baron,5 in a retrospective study, reported their experi-ence in performing an ERCP in patients lying in the supineposition, because many of them could not be placed ina prone position, and they compared the outcomes to

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another group of patients in whom an ERCP was performedin the conventional prone position. There were no dif-ferences between the 2 groups with respect to sex, proce-dural time, American Society of Anesthesiologists scores,or adverse cardiovascular events. Although the degree ofprocedural difficulty was significantly higher in the supinegroup, the overall rates of success, pre-cut sphincterotomyrates to gain selective ductal access, and complications weresimilar in the 2 groups. There was a trend toward a highernumber of episodes of desaturation in the supine groupin patients who were not intubated, although that did not

reach statistical significance. Ferreira and Baron5 concludedthat an ERCP with the patient in the supine position can besafely and effectively performed if specifically warranted byclinical circumstances. Their conclusion is notably differentfrom that of Terruzi et al,6 who, in a prospective study, per-formed an ERCP in patients randomized to be either in theprone or the supine position. They found that difficulty ofcannulation was markedly increased in the supine position,so much so that cannulation of the bile duct could not beachieved at all in the supine position in up to a third of theirpatients and, further, adverse cardiopulmonary events weremore frequently encountered in this group. Based on aninterim analysis, which led to the early termination of thestudy, they concluded that an ERCP in the supine positionis technically more demanding and, also, unsafe. The differ-ent conclusions could be partly explained by some of thedifferences in the definitions of study outcomes and, also,the types of study patients. Interestingly, 2 other studieswere recently reported as abstracts that addressed thesame issue. Diehl7 reviewed data from a prospectively col-lected database on 36 patients who were undergoing anERCP while in the supine position and found that the proce-dural success rate was marginally lower in these patients

When going beyond endoscopic consider-ations, it is also important to explore the issueof positioning of the patient during an ERCPfrom the perspective of sedation and airwaymanagement.

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Das Editorial

compared with that achieved by performing an ERCP withthe patient in the prone position. In another study, pre-sented during the 2007 Digestive Diseases Week, Tringaliet al8 reported the results of a randomized prospectivestudy that compared outcomes in 120 patients who wereundergoing an ERCP while in the supine or prone positionsand with conscious sedation. They found no differences inthe time to reach the major papilla, achieve cannulation ofthe desired duct, and total duration of the procedure; boththeir groups were comparable in terms of procedural suc-cess, technical difficulty, and complications.

When going beyond endoscopic considerations, it is alsoimportant to explore the issue of positioning of the patientduring an ERCP from the perspective of sedation and airwaymanagement. Although airway management in sedatedpatients is understandably more challenging in the proneposition, given that lung aeration in terms of functionalresidual capacity and other parameters of respiratorymechanics is actually better in the prone position and,also, the risk of aspiration of oropharyngeal secretion is low-est, there is no real advantage to have patients in the supineposition during an ERCP.9,10 In addition, it appears thatprocedural difficulty is higher and that the duration of theprocedure is increased in the supine position. Furthermore,to ensure adequate opacification of intrahepatic biliary rad-icles, it is often necessary to rotate the patient to differentpositions during a fluoroscopy, and this is much easier todo when starting from a prone position.

There are important limitations of all the studiesreported so far that address this issue. All of them lackpower in terms of sample size to exclude definitively typeI and II statistical errors. Although Ferreira and Baron5

should be complimented for attempting to generate evi-dence-based data applicable to the basics of endoscopicpractice, an important limitation of their study was that itwas based on the experience of a single endoscopist. It isobvious that the results achieved with a single pair of experthands in a tertiary-care institution cannot always be extrap-olated to the general practice of endoscopy, particularly anERCP. They also did not tell us about the specific indicationsof performing an ERCP in these patients. Endoscopists per-form most of their endoscopic procedures with the patientlying in the left lateral position, and it is surprising that noneof these studies explored the possibility of performing anERCP in the left lateral position. In the study by Ferreiraand Baron,5 a small proportion of patients underwent theprocedure in the left lateral decubitus, but a subgroup anal-ysis was not performed. The optical system of duod-enoscopes has improved vastly, and the field of vision ofmodern-day duodenoscopes is almost twice that of theiber-optic duodenoscopes that Oi2 used. With the improvedfield, depth of vision, and range of movement of the distalbending section of the duodenoscopes, as well as the avail-

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ability of many rotatable ERCP accessories, performing anERCP in the left lateral position should yield outcomescomparable with those performed in the prone positionbut without the disadvantages of a supine position. Well-planned prospective studies with an adequate sample sizewill be required to prove this point.

In the meantime what should we infer from this andother studies in this area? If a clinical situation warrantsthat an ERCP be performed in a decubitus other than theprone position, it should be attempted and would havea reasonable chance of success in expert hands.

Start by doing what is necessary; then do what ispossible; and suddenly you are doing the impossible.

St. Francis of Assisi (circa 1181-1226 AD)

DISCLOSURE

The author reports that there are no disclosures rele-vant to this publication.

Ananya Das, MD, FASGEDivision of Gastroenterology and Hepatology

Mayo Clinic ArizonaScottsdale, Arizona, USA

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3. Yakshe PN, Vennes JA, Sivak MV Jr. Technique of endoscopic retro-

grade cholangiopancreatography. In: Gastroenterologic endoscopy.

2nd ed. Philadelphia: WB Saunders; 2000. p. 845-62.

4. Cotton PB, Williams C. ERCP: diagnostic technique. In: Cotton PB,

Williams C, editors. Practical gastrointestinal endoscopy. 4th ed.

Cambridge (MA): Blackwell Science; 1996. p. 105-38.

5. Ferreira LEVVC, Baron TH. Comparison of safety and efficacy of ERCP

performed with the patient in supine and prone positions. Gastroint-

est Endosc 2008;67:1037-43.

6. Terruzzi V, Radaelli F, Meucci G, et al. Is the supine position as safe and

effective as the prone position for endoscopic retrograde cholangio-

pancreatography? A prospective randomized study. Endoscopy

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7. Diehl D. Supine patient positioning for ERCP: indications and out-

comes [abstract]. Gastrointest Endosc 2006;63:AB291.

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performing ERCP? Results of a prospective randomized trial [abstract].

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9. Pelosi P, Croci M, Calappi E, et al. The prone positioning during gen-

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10. Metheny NA. Risk factors for aspiration. JPEN J Parenter Enteral Nutr

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