Accuracy of the FEF C02 Detector in the Assessment of Endotracheal Tube Placement Sam T. Sum Ping,

MB, chB, FFARCS,

Mahesh P. Mehta,

MD,

and Tommy Symreng, MD,

PhD

University of Iowa, College of Medicine, Iowa City, Iowa

The sensitivity and reliability of the FEF end-tidal CO, detector were investigated for its suitability in the assessment of correct placement of an endotracheal tube. Sensitivity was determined by having eight blinded volunteers observe the color change in the FEF detector with the administration of different volumes and varying CO, concentrationsof gas mixture. The color change in the FEF detector was also assessed during esophageal ventilations before and after administration of carbonated beverage into the stomach of swine and during cardiopulmonary resuscitation in swine. An interpersonal variation was present among the blinded observers during the color-matching process. Different colors were ob-

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nidentified esophageal intubation remains a major cause of avoidable morbidity and mortality in anesthesia (1,2). Of the available methods of detecting esophageal intubation, the presence of carbon dioxide (COJ in the expired gas is probably the most convenient and reliable (3). One drawback of capnography is that it requires electronic equipment like the infrared monitor or the mass spectrometer to measure and display the waveform of COPpresent in the expired gas. This problem may be overcome by using the newly introduced FEF C02 detector (Fenem, New York, N.Y.), a small disposable device totally devoid of electronics. It has a nontoxic chemical indicator strip that responds quickly to exhaled C02by a reversible color change in a semiquantitative fashion when placed between the endotracheal tube and a breathing circuit. The color change is divided into three ranges: purple hue color is in the "A" range and represents 0.03% to