Bedside videoscopic placement of feeding tubes: development of fiberoptics through the tube

Pneumothorax from Intrapleural Placement of a Nasogastric Tube

Nasogastric tube insertion is a commonly performed procedure that can be associated with significant morbidity and even mortality. There is no universally accepted technique to confirm correct placement. Most confirmatory methods are performed after placement, therefore misplacement and potential complications may have already occurred. We report a case where a commonly used bedside confirmatory test gave false reassurance that the nasogastric tube was properly positioned, but a plain chest X-ray revealed a massive pneumothorax due to inadvertent intrapleural placement of the tube. Due to the deficiencies of traditional confirmatory bedside techniques, and the limitations of modern and more sophisticated confirmatory methods, the plain chest X-ray remains the gold standard test to confirm correct nasogastric tube placement. We appraise the methods commonly employed to confirm nasogastric tube placement, and discuss factors that may increase the risk of misplacement.

Gastric vs small-bowel feeding in critically ill children receiving mechanical ventilation: a randomized controlled trial

STUDY OBJECTIVES

To determine the effect of feeding tube position (gastric vs small bowel) on adequacy of nutrient delivery and feeding complications, including microaspiration, in critically ill children.

DESIGN

Randomized controlled trial.

SETTING

Pediatric ICU in a university teaching hospital.

PATIENTS

Seventy-four critically ill patients < 18 years of age receiving mechanical ventilation were randomized to receive gastric or small-bowel feeding.

INTERVENTIONS

All feeding tubes were inserted at the bedside. Color, pH, and bilirubin concentration of the feeding tube aspirates were used to guide placement. Final tube position was confirmed radiographically. Continuous feedings were advanced to achieve a caloric goal based on age and body weight. Tracheal secretions were collected daily and tested for gastric pepsin by immunoassay.

MEASUREMENTS AND RESULTS

Thirty-two patients were randomized to the gastric group, and 42 patients were randomized to the small-bowel group. Twelve patients exited the study because a small-bowel tube could not be placed at the bedside, leaving 30 patients in the small-bowel group. Gastric and small-bowel groups were similar at baseline in age, sex, percentage of ideal body weight, serum prealbumin concentration, and pediatric risk of mortality score. The percentage of daily caloric goal achieved was less in the gastric group compared to the small-bowel group (30 +/- 23% vs 47 +/- 22%, p < 0.01). No difference was found in the proportion of tracheal aspirates positive for pepsin between the gastric and small-bowel groups (50 of 146 aspirates vs 50 of 172 aspirates, respectively; p = 0.3). No differences were found in the frequency of feeding tube displacement, abdominal distension, vomiting, or diarrhea between groups.

CONCLUSIONS

Small-bowel feeds allow a greater amount of nutrition to be successfully delivered to critically ill children. Small-bowel feeds do not prevent aspiration of gastric contents.

Comparison of 2 Methods for Postpyloric Placement of Enteral Feeding Tubes

• Background Multiple techniques are available for postpyloric placement of feeding tubes. Administration of metoclopramide and air insufflation are easily accomplished at the bedside. Variable success rates have been reported for both procedures.

• Objectives To determine which method, administration of 10 mg of metoclopramide or gastric insufflation of 350 mL of air, is superior for successful postpyloric placement of feeding tubes at the bedside.

• Methods A prospective trial consisting of 60 adult patients randomized to have a feeding tube placed by 1 of 2 methods, either after intravenous administration of 10 mg of metoclopramide or via gastric insufflation of 350 mL of air. Placement results were confirmed by radiography.

• Results Among patients receiving narcotics, the 72% successful placement rate with insufflation was significantly better than the 11% success rate achieved with metoclopramide (P &lt; .001). Among the narcotic-free patients, the 83% success rate with metoclopramide was not significantly better than the 58% success rate with insufflation (P = .37). The difference in treatment effect between narcotic and narcotic-free groups was significant (P &lt; .001).

• Conclusion Patients receiving narcotics should have feeding tubes placed via the air insufflation technique. The use of continuous or regularly scheduled administration of narcotics significantly decreases the effectiveness of metoclopramide in successful placement of feeding tubes.

Gastric versus post-pyloric feeding: a systematic review

BACKGROUND

Our objective was to evaluate the impact of gastric versus post-pyloric feeding on the incidence of pneumonia, caloric intake, intensive care unit (ICU) length of stay (LOS), and mortality in critically ill and injured ICU patients.

METHOD

Data sources were Medline, Embase, Healthstar, citation review of relevant primary and review articles, personal files, and contact with expert informants. From 122 articles screened, nine were identified as prospective randomized controlled trials (including a total of 522 patients) that compared gastric with post-pyloric feeding, and were included for data extraction. Descriptive and outcomes data were extracted from the papers by the two reviewers independently. Main outcome measures were the incidence of nosocomial pneumonia, average caloric goal achieved, average daily caloric intake, time to the initiation of tube feeds, time to goal, ICU LOS, and mortality. The meta-analysis was performed using the random effects model.

RESULTS

Only medical, neurosurgical and trauma patents were enrolled in the studies analyzed. There were no significant differences in the incidence of pneumonia, percentage of caloric goal achieved, mean total caloric intake, ICU LOS, or mortality between gastric and post-pyloric feeding groups. The time to initiation of enteral nutrition was significantly less in those patients randomized to gastric feeding. However, time to reach caloric goal did not differ between groups.

CONCLUSION

In this meta-analysis we were unable to demonstrate a clinical benefit from post-pyloric versus gastric tube feeding in a mixed group of critically ill patients, including medical, neurosurgical, and trauma ICU patients. The incidences of pneumonia, ICU LOS, and mortality were similar between groups. Because of the delay in achieving post-pyloric intubation, gastric feeding was initiated significantly sooner than was post-pyloric feeding. The present study, while providing the best current evidence regarding routes of enteral nutrition, is limited by the small total sample size.

Delivery of enteral nutrition

There is increasing evidence that enteral feeding is superior to parenteral nutrition with regard to maintaining gut structure and function. Selection of the enteral access route depends on the type and anticipated duration of nutrient delivery. At present, enteral feeding devices can be divided into two major categories: those entering the gastrointestinal tract through the oral or nasal cavity (oroenteric or nasoenteric tubes) and those entering through the abdominal wall including gastrostomy, duodenostomy, or jejunostomy tubes. This article provides a review of methods to insert and confirm gastric and intestinal feeding tube placement. Care of the patient with an enteric tube will be described.

Placement of nasoenteral feeding tubes using magnetic guidance: retesting a new technique

OBJECTIVE

To study a new technique of intubating the small bowel using a newly developed nasoenteral feeding tube fitted with a magnet in its tip and guided for placement with an external magnet.

METHODS

The study was performed in medical and surgical wards of a university-affiliated Department of Veterans Affairs hospital on 42 patients referred by their attending physicians for tube placement. The newly designed feeding tube was inserted per nares into the stomach using traditional technique. As the tube was advanced, movement of the hand-held steering magnet was designed to guide the tip of the magnetic nasoenteral tube along the lesser curvature of the stomach, through the pyloric sphincter, and into the duodenum. Portable abdominal radiography confirmed the anatomic location of the tube tip.

RESULTS

Fifty-one intubations were performed on 42 subjects. In 45 intubations (88%), tubes passed into the duodenum. Twenty-seven (53%) met criteria for optimal placement in the second portion of the duodenum or distally. Six of 11 tubes (55%) that were not optimally placed were advanced to the distal duodenum on repositioning. Median procedure time for the initial intubations was 30 minutes (interquartile range 15-40). Median procedure time for last 10 intubations improved to 13 minutes (interquartile range 5-20). No complications were related to the procedure.

CONCLUSIONS

Enteral feeding tube placement using external magnetic guidance is a promising, novel technique which is deserving of further study.

Indicators of postpyloric feeding tube placement in children

OBJECTIVE

To determine the validity of five indicators (color, pH, and concentrations of bilirubin, pepsin, and trypsin in aspirated gastrointestinal secretions) in predicting postpyloric placement of feeding tubes in critically ill children.

DESIGN

Prospective, observational study.

SETTING

University teaching hospital.

PATIENTS

A total of 96 gastrointestinal aspirates were obtained from 53 children requiring placement of a nasoenteric feeding tube.

INTERVENTIONS

Feeding tubes were aspirated by applying suction with a 20-mL syringe. Repeat aspirates from the same patient were obtained on different days. All aspirations were performed within 30 mins of obtaining a radiograph to assess tube position.

MEASUREMENTS AND MAIN RESULTS

Aspirates were inspected visually for color. pH and bilirubin concentrations were determined at the bedside by using reagent strips. Pepsin and trypsin concentrations were measured spectrophotometrically in a research laboratory. The sensitivity, specificity, predictive values, and efficiency for each indicator and their 95% confidence intervals were determined based on the position of the feeding tube on the radiograph. Aspirate pH > or =6 had the lowest positive predictive value (76%, range 67% to 85%) but high negative predictive value (94%, range 89% to 99%) for determining postpyloric positioning of the feeding tube. Bilirubin concentration > or =5 mg/dL (> or =86 micromol/L) had the highest positive predictive value (96%, range 91% to 100%) and lowest negative predictive value (88%, range 81% to 95%). Overall efficiency was best for the appearance of a clear yellow aspirate color (93%, range 88% to 98%), pepsin concentration < or =20 microg/mL (94%, range 89% to 99%), and trypsin concentration > or =50 microg/mL (94%, range 89% to 99%).

CONCLUSIONS

Simple bedside assessment of gastrointestinal aspirate color, pH, and bilirubin concentration is useful for predicting feeding tube position. Use of these tests may reduce the number of radiographic studies needed to confirm postpyloric positioning. Laboratory-determined pepsin and trypsin concentrations predict tube position with a high degree of accuracy. Development of simple and inexpensive bedside tests for the detection of gastrointestinal enzymes may be useful.

Duodenal versus gastric feeding in ventilated blunt trauma patients: a randomized controlled trial

OBJECTIVE

To evaluate transpyloric feeds as they have been proposed as a means of providing enteric nutrition more rapidly and minimizing morbidity in ventilated trauma patients.

METHODS

Between July of 1994 and June of 1997, 80 adult ventilated trauma patients were enrolled in a randomized controlled trial of duodenal versus gastric feeds. Feeding was initiated within 72 hours of injury.

RESULTS

Forty-three patients received gastric feeds (G), and 37 patients received duodenal feeds (D). Mean age was 34.7+/-15.7 years (G) and 33.6+/-17.5 years (D); the difference in age was not significant (NS). Mean Injury Severity Score was 30.0+/-11 (G), 33.0+/-9.7 (D), NS. Mean Acute Physiology and Chronic Health Evaluation (APACHE II) score was 18.0+/-6.0 (G) and 18.0+/-7.4 (D), NS. Thirty-four of 43 patients were men (G) and 28 of 37 patients were men (D), NS. Use of narcotics and paralytics between the two groups was not significantly different. Energy requirements were 1.4 times basal energy expenditure at 2,127+/-304 Kcal (G) and 2,089+/-274 Kcal (D), NS. Intensive care unit length of stay was a median of 7 days (range, 3-32 days) (G) and 10 days (range, 3-24 days) (D), NS. Number of days on ventilator was a median of 5 days (range, 3-15 days) (G) and 9 days (range, 2-13 days) (D), NS. Hospital length of stay was a median of 25 days (range, 9-88 days) (G) and 30 days (range, 16-47 days) (D), NS. Recorded morbidity was not significantly different. Pneumonia rates were 42% (G) and 27% (D), NS. Time to tolerate full-strength feeds for 24 consecutive hours was 43.8 hours +/-22.6 (G) and 34.3 hours +/-7.1 (D), difference significant at p = 0.02.

CONCLUSION

Length of stay and ventilator days were not significantly different. A larger trial would be required to determine differences in the rates of pneumonia <20%. Transpyloric-duodenal feeds significantly reduce the time required to achieve targeted enteric nutrition.

Gastric versus duodenal feeding and gastric tonometric measurements

OBJECTIVE

To compare the influence of gastric and postpyloric enteral feeding on the gastric tonometric PCO2 gap (tonometric PCO2 - PaCO2).

DESIGN

A prospective, clinical trial.

SETTING

Two intensive care units in a university hospital.

PATIENTS

Twenty patients undergoing mechanical ventilation and enteral feeding without catecholamines, sepsis, or sign of hypoxia.

INTERVENTIONS

Patients were randomized to receive feeding through the tonometer (gastric group), or through a postpyloric tube (postpyloric group).

MEASUREMENTS AND MAIN RESULTS

The patients received tube feeding at a rate of 50 mL/hr during 4 hrs. Baseline measurements included: mean arterial pressure, heart rate, tonometric parameters, arterial gases, and arterial lactate concentration. Except for lactate concentration, these measurements were repeated after 1 and 4 hrs of enteral feeding and 2 hrs after stopping enteral feeding. During the study, arterial pH and PaCO2 did not change. During enteral feeding, the PCO2 gap increased in the gastric group from a mean of 7+/-5 to 17+/-14 (SD) torr (0.9 0.7 to 2.3+/-1.9 kPa) (p< .O01) and did not change in the postpyloric group (5+/-5 to 3+/-1 torr [0.7+/-0.7 to 0.4+/-0.1 kPa]). Two hours after stopping enteral feeding, the PCO2 gap was still increased in the gastric group (15+/-9 vs. 7+/-5 torr [2.0+/-1.2 vs. 0.9+/-0.7 kPa]) (p < .01).

CONCLUSION

The results indicate that gastric enteral feeding increased the PCO2 gap. However, postpyloric enteral feeding does not interact with gastric tonometric measurements and should be used when using gastric tonometry in enterally fed patients.

Enteral feeding techniques

Major technical advances in enteral nutrition include the use of erythromycin or magnetic guidance for the placement of the feeding tube into the duodenum, the development of new enteral tubes, and bedside methods to control the tube position. Percutaneous endoscopic jejunostomy is becoming a safe procedure with a high success rate. Specialized diets offer little or no clinical advantages when compared with standard polymeric diets.