Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Letter to the Editor

Separate circuit nasal cannulae for end-tidal CO2 monitoring may lead to hypoxia in patients with unilateral nasal airway obstruction

Jared C. Cohen, Anthony M-H. Ho, Heather D. O’Reilly, Glenio B. Mizubuti

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Dear Editor,

Monitored anesthetic care in the form of moderate or deep sedation is ubiquitous in anesthesia practice. Given that most sedative agents affect respiration, hypopnea and apnea (secondary to airway obstruction and/or central nervous system depression) is of constant concern, as it may lead to significant hypoxia and potentially respiratory or cardiovascular collapse. In this setting, nasal cannulae are commonly used to provide low-flow supplemental oxygen to patients undergoing procedural sedation. The utilization of capnography monitoring has been shown to decrease the incidence of hypoxia compared to supplemental oxygen alone, likely due to earlier detection of ventilatory inadequacy allowing prompt intervention prior to the development of critical hypoxia. Therefore, capnography monitoring is deemed mandatory for all patients undergoing general anesthesia or procedural sedation by many renowned anesthesiology societies worldwide. Hence, nasal cannulae with combined side-stream sampling ports for waveform capnography monitoring are commonly used by anesthesiologists.


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