To the Editor:-I would make an obvious suggestion to solve Dr. Pan's problem of a misplaced intravenous catheter used as a portal for CO2monitoring with the nasal cannula. The intravenous catheter may be eliminated entirely by using a system adapted at our Outpatient Surgical Center. I cut the Leur lock off at a 45 [degree sign] angle on the male end of the standard capnograph tubing that usually comes with each anesthesia circuit. An extra whole sampling capnograph tubing should always be at hand. After making a small cut with a No. 18 large needle into the supporting tube opposite one nasal prong, I pass the capnograph tubing tip so that it fits flush with the tip of one side of the nasal cannula, as depicted in Dr. Pan's letter, wherein he uses the intravenous catheter. The sampling tubing is taped to the nasal cannula for support. This system works well and follows CO sub 2 exhalation during monitored CO2care. If the anesthesia circuits are ordered with the capnograph tubing included, a supply of extra tubing occurs. By using these as described, an intravenous catheter cost is saved, and the described danger is eliminated.
Duke B. Weeks, M.D.
Professor; Department of Anesthesiology; Bowman Gray School of Medicine of Wake Forest University; Winston-Salem, North Carolina 27157–1009
(Accepted for publication October 9, 1997.)