Page 186 - Encyclopedia of Nursing Research

ENTERAL TUBE PLACEMENT n 153

tube placement when an NG/OG/Ni tube Approximately 15% of the gastric aspirates
is initially inserted or changed (Ellett et al., had pH values overlapping with the pH val-
submitted; Ellett, Cohen, et al., in prepara- ues of intestinal aspirates. in addition, pH E
tion; Gharib, Stern, Sherbin, & Rohrmann, values from four tubes inadvertently placed
1996; Jackson, Payne, & Bacon, 1990; Metheny, in the respiratory tract overlapped with the
Spies, & Eisenberg, 1988; Walsh & Banks, range in intestinal placements. Metheny,
1990). However, tube location must be mon- Smith, and Stewart (2000) found that the com-
itored frequently before being used for bination of pH, bilirubin, pepsin, and trypsin
feeding or medication instillation to ensure correctly classified 100% of respiratory place-
it has not become displaced, and the summa- ments and 93.4% of Gi placements in adults;
tive radiation risk of multiple radiographs as however, no bedside tests are commercially
well as their expense makes the development available for measuring bilirubin, pepsin, or
of adequate bedside monitoring methods trypsin, severely limiting their clinical useful-
imperative. ness. Although Ellett et al. (2005) found using
Multiple methods have been recom- the pH cutoff of 5 recommended by Metheny
mended for placing tubes in the distal duo- et al. for fasting adults was helpful in differ-
denum or jejunum. These vary from client entiating gastric from intestinal placement in
positioning, use of promotility agents, pH- a preliminary study involving children, their
sensing tube, self-propelled tube, magnets, recently completed randomized controlled
electrodes, fluoroscopic guidance, sono- trial found pH to be less helpful because sev-
graphic guidance, and endoscopic guid- eral tubes located in the pylorus or duode-
ance (Ellett, 2006). These methods vary in num on radiograph had acidic aspirate pH
cost, time involved, and success rates. in the readings, which incorrectly indicated they
future, possibly some of the lower cost meth- were placed in the stomach.
ods will be found useful in determining NG/ Placing the proximal end of the tube
OG tube location either reducing or eliminat- under water and observing for bubbles in
ing the need for radiographic verification. synchrony with expirations involves risk
Several bedside methods of detecting that clients will aspirate water on inspira-
NG/OG/Ni tube placement errors have been tion, especially those being mechanically
investigated in adults, including (a) aspirat- ventilated. There is evidence that CO 2 moni-
ing gastric contents and measuring the pH, toring has the potential to differentiate respi-
bilirubin, pepsin, and trypsin levels; (b) plac- ratory from Gi placement; however, it has
ing the proximal end of the tube under water yet to be used clinically (Burns, Carpenter,
and observing for bubbles in synchrony with & Truitt, 2001; Thomas & Falcone, 1998).
expirations; (c) measuring CO 2 level at the Simple auscultation is not a reliable method
proximal end of the tube; (d) auscultating for to assess tube position because injection of
a gurgling sound over the epigastrium or left air into the tracheobronchial tree or into the
upper quadrant of the abdomen; (e) examin- pleural space can produce a sound indistin-
ing the visual characteristics of tube aspirate; guishable from that produced by injecting
and (f) measuring and recording the length air into the Gi tract (Metheny, McSweeney,
from the nose or mouth to the proximal end Wehrle, & Wiersema, 1990). Radiation of
of the tube. Unfortunately, all of the bedside sound on auscultation is an even greater
methods have limitations. Each method will problem in children because of the small
be discussed separately. in a study of 800 distances between internal organs. Metheny,
aspirates collected from 605 fasting adults, Reed, Berglund, and Wehrle (1994) demon-
Metheny et al. (1999) found that gastric aspi- strated that visual characteristics improved
rates had significantly lower pH values (mean nurses’ predictions of stomach and intesti-
= 3.5) than intestinal aspirates (mean = 7.0). nal placements but reduced discrimination