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.


OBJECTIVE
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.


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 pCO2 >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 pCO2 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 pCO2 pre-ERCP, age, propofol doses, and procedure duration, the following differences were maintained (pCO2 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.
Department of Emergency, Virgen de la Concha Hospital, Zamora, Spain.
Miguel Angel
MA
Folgado
Department of Gastroenterology Service, Virgen de la Concha Hospital, Zamora, Spain.
Carlos
C
De la Serna
Department of Emergency, Virgen de la Concha Hospital, Zamora, Spain.
Alfonso
A
Llorente
Department of Gastroenterology Service, Virgen de la Concha Hospital, Zamora, Spain.
Sj
S
Rodríguez
Department of Investigation Unit, Virgen de la Concha Hospital, Zamora, Spain.
Carlos
C
Ochoa
Department of Pneumological, Ramón y Cajal Teaching Hospital, Madrid, Spain.
Salvador
S
Díaz-Lobato
Endoscopic retrograde cholangiopancreatography; high-risk patients; noninvasive ventilation