Laryngeal microsurgery under general anesthesia using small-bore endotracheal tubes: Blood gas analysis

This study reports variations observed under general anesthesia through small-bore endotracheal tubes in Po₂, Pco₂, Hco₃, percentage saturation of O₂, and pH levels in 39 patients who underwent laryngeal microsurgery lasting from 10 to 100 minutes. The tendency to an increase in Pco₂ levels reached statistical significance only at the 100th minute but did not constitute a risk for patients as values remained within the limits of “permitted hypercapnia.” Po₂, percentage saturation of oxygen, and Hco₃ levels did not vary significantly. pH values tended to fall (respiratory acidosis) in correlation to the increase in Pco₂. Small-bore endotracheal tubes can safely be used for laryngeal microsurgery when operating times are not longer than 100 minutes.