MEASURES TO TEST FEEDING TUBE PLACEMENT

确定相对简单、安全、廉价的措施

The identification of relatively simple, safe, inexpensive measures for testing placement of small-bore nasogastric and nasointestinal feeding tubes is the ultimate aim of this study. Presently used measures for testing placement of these widely used tubes (other than radiography) are largely ineffective. This is an important problem since nurses are responsible for testing placement of feeding tubes prior to each intermittent feeding and at least once a shift for patients receiving continuous tube feedings. It is not feasible, because of increased radiation risk and expense, to obtain x-rays to verify tube placement this often. Unfortunately, failure to detect an improperly placed feeding tube predisposes to pulmonary aspiration with increased morbidity and mortality. A variation of the commonly used auscultatory method will be tested for the purpose of predicting tube position, as will pH measurement of fluid aspirated from the tubes. The criterion against which the efficacy of the measures will be tested is radiographic examination (KUB). The study will be conducted in three acute care facilities; the sample size is 120 (pilot testing will be done in 10 subjects). In an attempt to differentiate between gastric and respiratory placement of the newly inserted tube, the researchers will aspirate fluid from the tube and test its pH within thirty minutes after insertion. Then, at the appropriate times, performance of both methods (pH testing and auscultation for sound variations) will be done twice in each of the 120 subjects once before and once after feedings are introduced through the tubes. It is hypothesized that nurses can predict at which point a feeding tube ends in the gastrointestinal (GI) tract by insufflating air through the tube while auscultating six abdominal sites for variation in sound quality and intensity with a doppler stethoscope. (The exact number and sites for auscultation will be refined during the pilot testing.) Also, it is hypothesized that the nurse can predict where small-bore tubes end in the GI tract by testing the pH of fluid aspirated from the tubes (fluid aspirated from the stomach will have an acidic pH, while fluid aspirated from the small intestine will have an alkalinic pH). Finally, it is hypothesized that nurses can differentiate between gastric and respiratory placement of initially inserted feeding tubes by checking the pH of fluid aspirated from the tubes via syringe (gastric aspirate would have an acidic pH while pulmonary secretions would likely be slightly alkaline).