Abstract
Background and study aims Sedation of high-risk patients is a relevant issue in interventional endoscopy. This
is especially because standard oximetric monitors display only hypoxia and not the
preceding hypercapnia. Therefore, the question arises whether use of a nasal positive
airway pressure (nPAP) system can decrease the rate of sedation-associated events.
Patients and methods A randomized, prospective trial was conducted at University Hospital Ulm, including
98 consecutive patients, identified as high-risk (American Society of Anesthesiologists
physical status ≥3) and scheduled for prolonged (>15 minutes) endoscopic procedures.
Patients underwent 1:1 randomization to two groups: interventional (nPAP-Mask) and
control (conventional oxygen supplementation). Levels of CO2 were measured noninvasively by transcutaneous capnometry device. The primary outcome
was incidence of hypoxia (SpO2 <90% over 10 seconds) and incidence of severe hypoxia was incidence of SpO2 <80% over 10 seconds. One of our secondary objectives was to determine if the nPAP-Mask
could result in significant CO2 retention among high-risk patients.
Results Data analysis showed lower incidence of hypoxia in the interventional group (10/47
vs. 31/251) P <0.05. Episodes of severe hypoxia (SpO2 <80% over 10 seconds) were more frequent in the control group (8/51) compared with
the intervention group (2/47) P <0.05. There was no significant difference in ΔCO2 levels in the interventional vs. control group (–6.01±7.66 vs. –7.35±8.59 mm Hg).
Conclusions In high-risk patients use of a nasal positive airway pressure system could significantly
lower risk of hypoxia, especially in prolonged procedures. The nPAP-Mask does not
induce CO2 retention when compared with conventional oxygen supplementation.
Keywords
Quality and logistical aspects - Sedation and monitoring - Quality management - Performance
and complications
