Background: Many patients develop hypoxia significantly during endoscopic retrograde cholangiopancreatography (ERCP). Monitoring the respiratory CO2 non-invasively is easy and relatively inexpensive. End-tidal carbon dioxide (EtCO2) reflects how well CO2 in the blood is carried to the lungs and exhaled. This study aimed to determine whether non-invasive CO2 monitoring (Dual-Guard Device-DGD) could substitute the invasive method.
Methods: This quasi-prospective study was conducted on 150 patients scheduled for elective ERCP procedures under conscious sedation. All patients were evaluated for systolic (SBP), diastolic (DBP), mean blood pressure (MBP), heart rate (HR), respiratory rate (RR), EtCO2, and peripheral oxygen saturation (SpO2) in addition to arterial blood gases (ABG), Ramsay Sedation Scale, participants' satisfaction, and any possible complications.
Results: The mean duration of procedures and sedation were 28.63 ± 9.5 and 41.25 ± 11.5 minutes, respectively. The mean HR and RR showed a significant (p<0.001) increase during follow-up. The mean SBP, DBP, and MBP showed a significant (p<0.001) decrease, while the mean EtCO2 and mean SpO2% significantly increased. The mean pH, PO2, and SaO2 significantly decreased postoperatively (p<0.001). In opposition, the mean HCO3 level preoperatively was significantly (p<0.001) lower than the postoperative level. Most patients recovered within 10 and 15 min. with 600/800 mg of propofol, and 47% of cases reported satisfaction. CO2 was significantly higher with ABG than DGD (p<0.001).
Conclusions: This study revealed poor reliability of non-invasive CO2 monitoring (using a Dual-Guard Device) compared to the invasive method (ABG) during conscious sedation for adult ERCP patients.