Utility of noninvasive ventilation in high-risk patients during endoscopic retrograde cholangiopancreatography

Background: There is little evidence on noninvasive ventilation (NIV) preventing respiratory complications in high-risk patients undergoing endoscopy procedures. Objectives: The objective of this study is to demonstrate that the application of NIV through a nasal interface can prevent the appearance of ventilatory alterations during endoscopic retrograde cholangiopancreatography (ERCP) in patients with risk factors associated with the development of hypoventilation. Patients and Methods: A non-randomized interventional study was performed on 37 consecutive high-risk patients undergoing ERCP. During the procedure, 21 patients received oxygen by nasal cannula (3 L/minute) and sixteen received NIV through a nasal mask. Arterial blood gas analyses were conducted before and immediately after the ERCP. An Acute Physiology and Chronic Health Evaluation (APACHE) score pre-ERCP was recorded. The complications during the procedure were recorded. Results: The groups with and without NIV were comparable. A post-ERCP pH of <7.35 was found in eight patients, who did not receive ventilatory support (38.1%) compared to zero patients in the NIV group (P = 0.006). A post-ERCP pCO(2) >45 mmHg was found in one case (6.3%) in the NIV-group and in nine cases in the nasal cannula group (42.9%: P = 0.01). The median pCO(2) post-ERCP was lower (36.5 +/- 6.2 vs. 44.5 +/- 6.8 mmHg) (P = 0.001) and median pH post-ERCP was higher (7.41 +/- 0.4 vs. 7.34 +/- 0.5) (P = 0.001) in patients treated with NIV. In the multivariate analysis, after adjusting for gender, the APACHE score, pH and pCO(2) pre-ERCP, age, propofol doses, and procedure duration, the following differences were maintained (pCO(2) difference = 5.54, 95% Confidence Interval (CI) =2.3 - 8.7, pH difference = 0.047, and 95% CI = 0.013 - 0.081). Among the 37 procedures, four complications occurred: One in the NIV group and three in the nasal cannula group. None of them was related to NIV. Conclusions: Our preliminary results demonstrate that in high-risk patients undergoing ERCP, hypercapnia and respiratory acidosis are frequent. NIV prevents the appearance of these complications.