Is the Supine Position as Safe and Effective as the Prone Position for Endoscopic Retrograde Cholangiopancreatography? A Prospective Randomized Study

Background and Study Aims: Endoscopic retrograde cholangiopancreatography (ERCP) is usually performed with the patient lying in the prone position, on the assumption that this position is optimal for cannulation of the papilla and for obtaining good-quality radiographic images. The supine position, however, may be more comfortable for the patient and may facilitate airway management, and this study aimed to compare the two positions in terms of procedure outcome, safety, and patient tolerance.
Patients and Methods: Consecutive patients who were undergoing ERCP were randomized to start the procedure in either the prone position or the supine position. Patients under the age of 18 years, intubated patients, and those who had already undergone endoscopic sphincterotomy were excluded. The difficulty of cannulation was assessed using the Freeman score (1 = one to five attempts; 2 = six to 15 attempts; 3 = more than 15 attempts; 4 = failure of cannulation). Total procedure time, patient tolerance, willingness to undergo ERCP in the future, and procedure-related adverse cardiorespiratory events (oxygen desaturation, tachycardia, bradycardia) were also recorded.
Results: A total of 34 patients were evaluated (21 men, 13 women; mean age 68, range 20 - 96), 17 patients in each group. Demographic and clinical features, and the indications for the procedure were similar for the two patient groups. The median Freeman score was significantly lower in the prone group compared with the supine group (1 vs. 3, P = 0.0047, rank sum test). Biliary cannulation was achieved in all patients in the prone group, but was not achieved in five patients (29 %) in the supine group (P = 0.052). In four of these five patients, biliary cannulation was successfully achieved after turning the patient into the prone position. The percentage of patients unwilling to repeat the ERCP procedure in the future was higher in the supine group (29 % vs. 6 %, P = 0.087); the mean tolerance score and mean total procedure time were similar in the two groups. Seven patients in the supine group experienced at least one adverse cardiorespiratory event, compared with only one patient in the prone group (41 % vs. 6 %, P = 0.039).
Conclusions: ERCP performed with the patient in the supine position is technically more demanding for operators used to working with patients in the prone position and carries a greater risk of adverse cardiorespiratory events in nonintubated patients.

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