Utility of endtidal carbon dioxide monitoring in detection of hypoxia during sedation for brain magnetic resonance imaging in children with developmental disabilities

Background: We have shown previously that children with developmental disabilities have three times higher incidence of sedation-related hypoxia when compared with normal children. Objectives: Our objectives were to describe the changes in endtidal carbon dioxide (ETCO ₂) values and the utility of ETCO ₂ monitoring in earlier identification of hypoxia during sedation for brain magnetic resonance imaging (MRI) in children with developmental disabilities. Methods: We conducted a prospective observational study of a convenience sample of 150 children with developmental disabilities aged 1-10 years who received intravenous sedation for brain MRI. Children were sedated and monitored according to the institution's sedation protocol. We recorded ETCO ₂ levels, hypoxia, and adverse events during sedation. Hypoxia was defined as SpO ₂ < 93%. A change in ETCO ₂ level ≥ 10 mm Hg from presedation baseline, an intra-sedation ≥ 50 mm Hg, and loss of capnographic waveform were considered as significant ETCO ₂ abnormalities. Results: Of the children, 80.7% (121/150) were sedated with a combination of pentobarbital and fentanyl. ETCO ₂ abnormalities were noted in 42.6% (64/150) of sedation encounters. Hypoxia occurred in 18% (27/150) of subjects. ETCO ₂ abnormalities were documented in 19(70%) patients with hypoxia before changes in pulse oximetry were noted. ETCO ₂ changes were noted a mean of 4.38 ± 1.89 min prior to occurrence of hypoxia. Conclusions: ETCO ₂ abnormalities and hypoxia occur commonly during sedation in children with developmental disabilities. ETCO ₂ monitoring is useful in early recognition of impending hypoxia during sedation in children with developmental disabilities.