Nitrous Oxide and Air-filled Balloon-tipped Catheters

Open Access
Publisher Website
Google Scholar
Abstract
The differential solubilities of gases permit N2O diffusion into air-filled body cavities, increasing their size and/or pressure. An air-filled balloon-tipped catheter represents a body cavity that may be affected by the diffusion of N2O, and could account for the clinical observation that more gas was aspirated than injected during insertion of Swan-Ganz (S-G) catheters in patients receiving N2O anesthesia. An accompanying increase in balloon diameter could conceivably account for difficulties in floating the tip into the pulmonary outflow tract. To help substantiate these observations, balloon volumes of 3 S-G catheters were measured at 0.5, 1, 2, 3, 4, 5, 10, 20 and 30 min in various N2O and O2 mixtures, and the diameters of the balloon were compared with published diameters of pulmonary outflow tracts. The volume changes were near maximum between 5-10 min, increasing to 30-150% depending on the N2O concentration. The increases in balloon diameter, when compared to pediatric pulmonary outflow tract diameters, could account for difficulties in passage of the catheter tip through the pulmonary outflow tract. Manipulation of S-G catheters under N2O anesthesia should be done with intermittent deflation of the balloon every few minutes.

This publication has 0 references indexed in Scilit: