URJHS Volume 7

Current Methods Nurses Use to Place and Maintain Nasogastric and Orogastric Tubes

Nicole Quainoo
Indiana University School of Nursing

Abstract

Enteral nutrition has become widely preferred over parenteral nutrition in adults and children with functioning gastrointestinal tracts when the need for tube feeding is expected to be 6 weeks or less. The purposes of this study were to determine the methods used by nurses to determine the correct insertion distance for placing nasogastric/orogastric (NG/OG) tubes and to determine the internal position after the tube has been placed. There is a need to change practices of insertion and determining placement, according to the most up-to-date evidence, in order to increase the safety of clients receiving enteral tube feedings.

Introduction

Enteral nutrition has become widely preferred over parenteral nutrition in adults and children with functioning gastrointestinal tracts when the need for tube feeding is expected to be 6 weeks or less. It is estimated that between 750,000 and 1,000,000 nasoenteric tubes are used in adults and children per year (National Patient Safety Agency, 2005). In a cross-sectional study done in 2005-2006 in a large Midwestern children’s hospital, 44 percent of the children had enteral tubes in place. Of the 1,206 enteral tubes identified, 2/3rds were nasogastric/orogastric (NG/OG) tubes (Chin, unpublished manuscript).

Literature Review

Previous studies found NG/OG tube placement errors to be common, with prevalence rates of errors in adults varying from 1.3 percent (McWey, Curry, Schabel, & Reines, 1988) to 89.5 percent (Niv & Abu-Avid, 1988), depending on the definition of error. Prevalence was lower when placement error was narrowly defined as tubes incorrectly placed into the airway or perforating the gastrointestinal tract upon insertion (Ghahremani & Gould, 1986; McWey et al., 1988). Higher rates were found when error was broadly defined as gastric tubes misplaced in other ways, such as not in the stomach or not in the acid pool within the stomach when fluid for gastric analysis was desired (Niv & Abu-Avid, 1988; Rombeau & Barot, 1981). When placement error was defined as the tube tip and/or orifices not in the stomach, NG/OG tube placement error rates of 21 percent were reported in two studies of children (Ellett & Beckstrand, 1999; Ellett, Maahs, & Forsee, 1998). Gallaher, Cashwell, Hall, Lowe, and Ciszek (1993) reported a 38 percent OG tube error rate in very low birth weight infants using the latter definition of error rate. Although the estimates of tube placement errors vary, there is no doubt that they are too common and that tubes misplaced on insertion can lead to serious complications, such as aspiration pneumonia and malabsorption, manifested as diarrhea and failure to gain weight (Goodwin, Graves, & Haberkern, 1985; Hopper et al., 1983).

Shiao and DiFiore (1996), in a telephone survey of Level II and III newborn nurseries, found that 98 percent of the nurses measured insertion distance from the nose or mouth to the earlobe and then to the xiphoid process, 1 percent measured from the mouth to the nose and then to the xiphoid process, and 1 percent used a length based on the infant’s weight.

There are currently five evidence-based methods to measure the distance feeding tubes should be inserted. The most commonly used method for measuring tube insertion distance in hospitals is the nose–ear–xiphoid (NEX) method. This is obtained by measuring from the nose to the earlobe and then to the bottom of the xiphoid process. This method was developed using an unreported number of infants at autopsy. Ziemer and Carroll (1978) had previously reported the NEX method to be too short, because “gastric contents cannot usually be aspirated until the tubing is advanced further” (p. 1543). According to Tedeschi, Altimier, and Warner (2004), when placing tubes based on the NEX measurement guideline, tubes were noted in the lower esophagus on x-ray with unacceptable frequency.

When Tedeschi and colleagues (2004) adopted another measurement guideline, nose-ear-umbilicus (NEU) (not evidenced-based); x-rays of premature infants revealed gastric tubes placed too low, through the pylorus into the duodenum. This prompted use of the nose-ear-midumbilicus (NEMU) method, which was also recommended over the NEX method by Ziemer and Carroll (1978), which involves measuring from the nose to the earlobe and then to a point midway between the xiphoid process and the umbilicus. The Gallaher, Cashwell, Hall, Lowe, and Ciszek (1993) method is based on weight and was specifically developed for very low birth weight infants. The researchers recommend an insertion distance of 13 cm for premature infants < 750 gm, 15 cm for infants weighing between 750-999 gm, 16 cm for infants weighing 1000-1249 gm, and 17 cm for infants weighing 1250-1499 gm. With these minimal insertion lengths, the error rate was decreased from 38 percent to 14 percent in their newborn nursery (Gallaher et al.).

For adults, the NEX method was incorporated into the formula: NEX-50/2+50 cm (Hanson, 1979). This formula reportedly provided 91 percent confidence that tube tip placement is in the stomach between 1 and 10 cm, compared to 72 percent confidence using the traditional NEX measurement. The newest method of insertion distance measurement in adults is a three-variable model using gender, weight, and nose to the umbilicus with the adult’s head flat on the bed (GWNUF) (Ellett et al., 2005).

Once a tube is correctly placed into the stomach on insertion, its position must be checked prior to every feeding or at least three times a day. Shiao and DiFiore (1996) found 82 percent of nurses working in the newborn nurseries surveyed used auscultation (listening through a stethoscope over the stomach while injecting a small amount of air into the tube), 9 percent relied on x-ray verification, 5 percent used pH testing of gastric aspirates, 4 percent used existing centimeter markings or tape markings on the tube, and 1 observed for bubbling when the tube was held under water to detect respiratory placement. Metheny, McSweeney, Wehrle, and Wiersema (1990) reported the accuracy of auscultation of air injected into the tube, the most commonly used method, to be only 34 percent accurate in determining tube position in the gastrointestinal tract in adults. In a study of 800 aspirates collected from 605 fasting adults, Metheny et al. (1999) found that gastric aspirates had significantly lower pH values (mean 3.5) than did intestinal aspirates (mean 7.0). In a later study of fed adults, Metheny and Stewart (2002) suggested that tube aspirate with a pH ≤ 6 was likely to be from the stomach and aspirate with a pH of >6 was likely to be from the intestine or respiratory tract. Although different bedside methods of testing NG/OG tube placement are used, radiography is considered the gold standard for determining the internal location of NG/OG tubes. However, radiography cannot be used every time tube position needs to be assessed (at least three times per day) because of the radiation exposure to the child and the expense. Finding methods for accurate determination of the location of NG/OG tubes are imperative if errors in tube placement are to be decreased (Ellett, 2004).

The purpose of this study was to assess what methods were utilized by nurses locally to determine the correct insertion distance for NG/OG tubes and to determine position after the tube had been placed.

Methods

Design

An in-person quantitative interview was conducted with each nurse willing to participate using a predetermined set of questions.

Sample

The sample consisted of 25 nurses caring for adults and 25 nurses caring for children. Nurses at three Clarian hospitals who have placed 1 or more NG or OG tubes in adults or children were asked to participate.

Procedure

Nurses were recruited by the co-investigator and asked to sign a consent form after the study was explained and their questions answered. The interviews were conducted in a private area In or near their work unit. Notes were taken by the student co-investigator. The following questions were asked regarding the procedure each nurse used to place and test placement of NG/OG tubes:

1. What is your age? Specific categories ( < 19, 20-30, 31-40, 41-50, 51-60, 61-70, and 71-80 years) were offered.
2. How many years have you been a nurse?
3. Roughly how many nasogastric/orogastric tubes have you placed? Specific categories (<10, 10-50, and >50) were offered.
4. Roughly how many nasogastric/orogastric tubes have you placed in adults? The same categories were offered.
5. Roughly how many nasogastric/orogastric tubes have you placed in children? The same categories were offered.
6. What method do you use to predict the distance to insert a NG/OG tube?
7. Once the tube is inserted, how do you test placement?
8. Do you use the same method for routine placement testing?
9. Is x-ray required before you may begin feeding?
10. In general, how often do you think NG/OG tubes are misplaced upon insertion? Specific categories: never, rarely, sometimes, and often were offered.

Results

Nose-ear-xiphoid (NEX) was the most common method being used by 62 percent of the nurses. This method is currently being challenged by pediatric nurse researchers as being too short, especially in children, leaving the tip and/or openings on the tube in the esophagus (Beckstrand, Ellett, & McDaniel, 2007). Seventy-two percent of nurses were using some variation of NEX. The remaining nurses were using various methods that were not evidence based. Auscultation, the most commonly used method of checking placement once the tube is inserted, has already been shown by several nurse researches to be unreliable. Only 6 percent of the nurses were using aspiration of gastric contents and testing pH, which is the method currently recommended by the evidence. Sixty-six percent of nurses believe that tubes are rarely or never misplaced upon insertion, although 34 percent of the participants realized that they were either often or sometimes misplaced upon insertion.

Conclusion

In general, in pediatrics there is some movement toward obtaining an x-ray prior to feeding in newly placed tubes, but this trend was not observed in adult care. The NEX method needs to be further studied in adults. Also, there is a need to change practices of insertion and determining placement, according to the most up-to-date evidence, in order to increase the safety of clients receiving enteral tube feedings.

References

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Chin, P. A. Prevalence of Enteral Tubes in a Large Midwestern Children’s Hospital (unpublished manuscript).

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