Background In the medical intensive care unit at the University of Virginia Health System, capnography is used to detect end-tidal carbon dioxide to protect patients from inadvertent airway cannulation during placement of gastric tubes.

Objectives To compare the method in which capnography is used with a method in which a colorimetric carbon dioxide detector is used and to determine what variables affect accurate placement of gastric tubes.

Methods A prospective convenience sample of 195 gastric tube insertions was studied in 130 adult patients in a medical intensive care unit. Standard insertions of gastric tubes (done with capnography) were simultaneously monitored by using a disposable colorimetric device, with a color change indicating the presence of carbon dioxide.

ResultsInsertion variables included tube type (60% Salem sump tubes, 40% soft-bore feeding tubes), route of insertion (71% oral, 29% nasal), mechanical ventilation (81%), and decreased mental status (72%). Carbon dioxide was successfully detected with the colorimetric indicator (within seconds) in all insertions in which carbon dioxide was detected by capnography. When carbon dioxide was detected (27% of insertions), the tubes were withdrawn and reinserted. Carbon dioxide detection during tube placement was significantly associated with nasal insertions (P = .03) and spontaneously breathing/nonintubated status (P=.01) but not with mental status or tube type.

Conclusions A colorimetric device is as accurate as capnography for detecting carbon dioxide during placement of gastric tubes.

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