Indicators of postpyloric feeding tube placement in children

Procedures for a Transpyloric Feeding Tube Inserted Into Newborns and Infants: A Systematic Review

BACKGROUND

Enteral feeding by a transpyloric tube in critically ill infants is indicated when there is a failure in gastric feeding. However, there is a wide variability regarding the insertion technique.

PURPOSE

To perform a systematic review of the methods for inserting a transpyloric feeding tube in newborns and infants.

DATA SOURCES

Nine databases, without date or language restrictions, accessed in September 2021.

STUDY SELECTION

A systematic review of experimental and nonexperimental studies, according to the "Patient/problem; Intervention; Comparison; Outcome" strategy and the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. The clinical question was about the measurement and insertion techniques, as well as the success rates of properly placing a transpyloric tube in newborns and infants.

DATA EXTRACTION

Two authors (N.M.Q. and J.F.S.) analyzed 6 observational descriptive prospective studies, all of them published in peer-reviewed indexed medical journals and one in the official journal of the National Association of Neonatal Nurses.

RESULTS

The success rate varied between 70% and 100%. There was an important variability in the type of tube, measurement method, and insertion techniques. It was found that the most common strategies to achieve proper positioning were glabella-calcaneal measurements, gastric air insufflation, and right lateral decubitus.

IMPLICATIONS FOR PRACTICE

A transpyloric catheter insertion protocol needs to be established in each neonatal unit, according to the literature findings.

IMPLICATIONS FOR RESEARCH

Randomized controlled studies that evaluate the gastric air insufflation technique and other adjuvant measures could elucidate the knowledge gap concerning the correct positioning of transpyloric tubing in newborns and infants.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Characterisation of fasted state gastric and intestinal fluids collected from children

Fundamental knowledge about the composition of intestinal fluids in paediatric populations is currently unavailable. This study aimed to characterise gastric and intestinal fluid from paediatric populations. Gastric and intestinal fluid samples were obtained during routine clinical endoscopy from paediatric patients at a large teaching hospital. These fluids were characterised to measure the pH; buffer capacity; osmolality; bile acid concentration and composition. A total of 55 children were recruited to the study aged from 11 months to 15 years of age where 53 gastric fluid samples and 40 intestinal fluid samples were obtained. pH values recorded ranged from pH 0.57 to 11.05 (median: 2.50) in gastric fluids and from 0.89 to 8.97 (median: 3.27) in intestinal fluids. The buffer capacity did not change significantly between gastric and intestinal fluids with median values of 12 mM/L/ΔpH for both fluids. Gastric fluid osmolality values ranged from 1 to 615 mOsm/kg, while intestinal fluid values ranged from 35 to 631 mOsm/kg. Gastric fluid bile acid concentrations ranged from 0.002 to 2.3 mM with a median value of 0.017 mM whilst intestinal fluid bile acid concentrations ranged from 0.0008 to 3.3 mM with a median value of 0.178 mM. Glycocholate; taurocholic acid; glycochenodeoxycholate and taurochenodeoxycholate were the most commonly identified bile acids within paediatric intestinal fluids. All compositional components were associated with large inter-individual variability. Further work is required to develop simulated paediatric media and to explore the impact of these media on drug solubility and dissolution.

Biopharmaceutical considerations in paediatrics with a view to the evaluation of orally administered drug products - a PEARRL review

OBJECTIVES

In this review, the current biopharmaceutical approaches for evaluation of oral formulation performance in paediatrics are discussed.

KEY FINDINGS

The paediatric gastrointestinal (GI) tract undergoes numerous morphological and physiological changes throughout its development and growth. Some physiological parameters are yet to be investigated, limiting the use of the existing in vitro biopharmaceutical tools to predict the in vivo performance of paediatric formulations. Meals and frequencies of their administration evolve during childhood and affect oral drug absorption. Furthermore, the establishment of a paediatric Biopharmaceutics Classification System (pBCS), based on the adult Biopharmaceutics Classification System (BCS), requires criteria adjustments. The usefulness of computational simulation and modeling for extrapolation of adult data to paediatrics has been confirmed as a tool for predicting drug formulation performance. Despite the great number of successful physiologically based pharmacokinetic models to simulate drug disposition, the simulation of drug absorption from the GI tract is a complicating issue in paediatric populations.

SUMMARY

The biopharmaceutics tools for investigation of oral drug absorption in paediatrics need further development, refinement and validation. A combination of in vitro and in silico methods could compensate for the uncertainties accompanying each method on its own.

Testing Placement of Gastric Feeding Tubes in Infants

BACKGROUND

Inadvertent positioning of a nasogastric tube in the lung can cause serious complications, so identifying methods to detect improperly inserted tubes is imperative.

OBJECTIVES

To compare the sensitivity, specificity, and negative and positive predictive values of 4 pH cut points (< 4.0, < 4.5, < 5.0, and < 5.5) in differentiating gastric and tracheal aspirates under various treatment conditions and to explore the utility of a pepsin assay for distinguishing between gastric and tracheal aspirates.

METHODS

Gastric and tracheal aspirates were collected from critically ill infants undergoing mechanical ventilation who had nasogastric or orogastric feeding tubes. Aspirates were tested with colorimetric pH indicators and a rapid pepsin assay. Information about treatment conditions was obtained from medical records.

RESULTS

Two hundred twelve gastric aspirates and 60 tracheal aspirates were collected from 212 patients. Sensitivity was highest and specificity was lowest at the gastric aspirate pH cut point of less than 5.5. Positive predictive values were 100% at all pH cut points less than 5.0. Negative predictive values were higher at the pH cut point of less than 5.0 than at cut points less than 4.5. A higher percentage of pepsin-positive readings was found in gastric aspirates (88.3%) than in tracheal aspirates (5.4%).

CONCLUSION

For a desired positive predictive value of 100%, a pH cut point of less than 5.0 provides the best negative predictive values, regardless of gastric acid inhibitor administration and feeding status. The pepsin assay is promising as an additional marker to distinguish gastric from tracheal aspirates.

Monitoring Feeding Tube Placement

The purpose of this literature review is to describe currently available bedside methods to determine feeding tube placement. Described first are methods used at the time of blind insertion to distinguish between gastric and respiratory placement and gastric and small-bowel placement. Discussed next are methods used after feedings are initiated to determine if the tube has remained in the desired position in the gastrointestinal tract. Some of the methods are research-based, whereas others are opinion-based. The level of accuracy of the methods discussed in the review varies widely. No sure non-radiographic method exists to differentiate between respiratory, esophageal, gastric, and small bowel placement of blindly inserted feeding tubes in the fed or unfed state. However, a combination of some of the simpler and more accurate methods may be used to guide feeding tube placement during insertion and help identify the point at which an abdominal radiograph is most likely to confirm the desired location. In addition, methods described in this review can help determine when a radiograph is needed to confirm that a feeding tube has remained in the correct position after the initiation of feedings. Minimizing the number of radiographs taken to assure correct tube placement is important, especially in young children and in the critical care setting where the need for radiographs for other reasons is common.

ASPEN Safe Practices for Enteral Nutrition Therapy [Formula: see text]

Enteral nutrition (EN) is a valuable clinical intervention for patients of all ages in a variety of care settings. Along with its many outcome benefits come the potential for adverse effects. These safety issues are the result of clinical complications and of process-related errors. The latter can occur at any step from patient assessment, prescribing, and order review, to product selection, labeling, and administration. To maximize the benefits of EN while minimizing adverse events requires that a systematic approach of care be in place. This includes open communication, standardization, and incorporation of best practices into the EN process. This document provides recommendations based on the available evidence and expert consensus for safe practices, across each step of the process, for all those involved in caring for patients receiving EN.

Naso-enteric Tube Placement: A Review of Methods to Confirm Tip Location, Global Applicability and Requirements

BACKGROUND

The insertion of a tube through the nose and into the stomach or beyond is a common clinical procedure for feeding and decompression. The safety, accuracy and reliability of tube insertion and methods used to confirm the location of the naso-enteric tube (NET) tip have not been systematically reviewed. The aim of this study is to review and compare these methods and determine their global applicability by end-user engagement.

METHODS

A systematic literature review of four major databases was performed to identify all relevant studies. The methods for NET tip localization were then compared for their accuracy with reference to a gold standard method (radiography or endoscopy). The global applicability of the different methods was analysed using a house of quality matrix.

RESULTS

After applying the inclusion and exclusion criteria, 76 articles were selected. Limitations were found to be associated with the 20 different methods described for NET tip localization. The method with the best combined sensitivity and specificity (where n > 1) was ultrasound/sonography, followed by external magnetic guidance, electromagnetic methods and then capnography/capnometry. The top three performance criteria that were considered most important for global applicability were cost per tube/disposable, success rate and cost for non-disposable components.

CONCLUSION

There is no ideal method for confirming NET tip localisation. While radiography (the gold standard used for comparison) and ultrasound were the most accurate methods, they are costly and not universally available. There remains the need to develop a low-cost, easy-use, accurate and reliable method for NET tip localization.

The pH of Feeding Tube Aspirates From Critically Ill Infants

BACKGROUND

The extent to which gastric acid inhibitors and feedings affect gastric pH in infants is unclear.

OBJECTIVES

To compare pH values of gastric aspirates from infants according to use or no use of gastric acid inhibitors and feedings.

METHODS

Colorimetric pH tests were used to measure the pH of aspirates from feeding tubes in 54 critically ill infants; 29 of the gastric aspirates were from infants who did not receive acid inhibitors or feedings, 13 were from infants who received acid inhibitors but no feedings, 3 were from infants who received feedings but no acid inhibitors, and 5 were from infants who received both acid inhibitors and feedings. The remaining 4 feeding tubes were in nongastric sites.

RESULTS

Individual pH readings of 5.5 or less were found in 97% of the gastric aspirates from infants with no recent feedings or acid inhibitors, 77% of the gastric aspirates from infants who received acid inhibitors, and 67% of the gastric aspirates from infants with recent feedings. Among 2 esophageal aspirates and 2 duodenal aspirates, 1 of each type had a pH less than 5.5. A pH cut point of 5.5 or less did not rule out esophageal or duodenal placement.

CONCLUSIONS

The pH of gastric aspirates from critically ill infants is often 5.5 or less, regardless of the use of acid inhibitors, feedings, or both. Most likely a cut point of 5.5 or less would rule out respiratory placement because tracheal pH is typically 6.0 or higher.

Examining the evidence to guide practice: challenging practice habits

Nurses are the largest segment of the nation's health care workforce, which makes nurses vital to the translation of evidence-based practice as a practice norm. Critical care nurses are in a position to critically appraise and apply best evidence in daily practice to improve patients' outcomes. It is important for critical care nurses to continually evaluate their current practice to ensure that they are applying the current best evidence rather than practicing on the basis of tradition. This article is based on a presentation at the 2013 National Teaching Institute of the American Association of Critical-Care Nurses. Four practice interventions that are within the realm of nursing are critiqued on the basis of current best evidence: (1) turning critically ill patients, (2) sleep promotion in the intensive care unit, (3) feeding tube management in infants and children, and (4) prevention of venothromboembolism…again. The related beliefs, current evidence, and implications for practice associated with each topic are described.

Potential risk of malposition of nasogastric tube using nose-ear-xiphoid measurement

BACKGROUND

Correct placement of nasogastric tubes provide proper functionality and maximize benefit and minimize risk. The Nose-Ear-Xiphoid (NEX) body surface estimate method is a long-lasting technique, and this study was conducted to evaluate the correlation between NEX method and the secure insertion depth of nasogastric tube.

MATERIALS AND METHODS

Thirty patients with nasogastric tube insertion who received whole body positron emission tomography with computerized tomography scan (PET-CT) were recruited. All data were gathered in the image center, which included Nose-Ear (NE), Ear-Xiphoid (EX), Nose-Ear-Xiphoid (NEX), glabella-xiphoid (GX) and glabella-umbilicus (GU) lengths. The distances of the inserted portion of the nasogastric tube between the cardiac and the nostril were measured by multiplanar reconstruction algorithm.

RESULTS

Only one patient successfully placed all side-holes into the stomach while using NEX method to estimate inserting depth. Twenty-nine patients (96.7%) failed to place correctly. Fourteen participants had one or more side-holes in both the esophagus and the stomach sides. Fifteen patients could not pass through any side-hole across the gastroesophageal junction. They had shorter EX distances (p = 0.02), but no difference among the NE distances. Body height had the highest statistical correlation with nasogastric tube length (adjusted R(2) = 0.459), as compared with the NEX, GX and GU body surface methods.

CONCLUSION

This study suggests that NEX method is inappropriate for adult patients to estimate the ideal inserting length of nasogastric tube. Physicians should realize these underinsertions with any side-hole above the gastroesophageal junctions may increase the potential risk of complications.

Comparing bedside methods of determining placement of gastric tubes in children

PURPOSE

The purpose of this study was to compare the accuracy and predictive validity of pH, bilirubin, and CO2 in identifying gastric tube placement errors in children.

DESIGN AND METHODS

After the tube was inserted into 276 children, the CO2 monitor reading was obtained. Fluid was then aspirated to test pH and bilirubin.

RESULTS

Lack of ability to obtain tube aspirate was the best predictor of NG/OG placement errors with a sensitivity of 34.9% and a positive predictive value of 66.7%. Measuring pH, bilirubin, and CO2 of tube aspirate was less helpful.

PRACTICE IMPLICATIONS

Healthcare providers should suspect NG/OG tube misplacement when no fluid is aspirated.

Enteral feeding tubes: are insertion techniques and positioning based on anatomical evidence?

Patients in whom oral energy intake is insufficient for daily needs may develop malnutrition and its complications, such as increased infection rates, increased length of hospitalization, and death. Enteral feeding is beneficial for these patients. However, this therapy is not without complications related to the insertion and placement of enteral feeding tubes. This review aims to identify from the literature different techniques for insertion and the methods used to evaluate the placement of enteral feeding tubes.

Biomarkers in the diagnosis of aspiration syndromes

Recognizing and managing the different types of aspiration events remain a challenging task due to the lack of distinguishing clinical or laboratory characteristics. Numerous biomarkers in serum, sputum and bronchoalveolar lavage have been studied, and their role in the recognition of aspiration remains controversial at this time. Recent animal investigations using an array of biomarkers based on distinct pathogenic features of each aspiration event have produced promising results; however, they have not been validated in humans. Newer markers are being introduced as diagnostic and prognostic tools in conditions such as community-acquired pneumonia and sepsis, but they have not been examined in aspiration. The present review summarizes the different biomarkers that have been studied in aspiration and those who might have a potential clinical use in the future.

Fluoroscopy-guided insertion of nasojejunal tubes in children - setting local diagnostic reference levels

BACKGROUND

Little is known about the radiation burden from fluoroscopy-guided insertions of nasojejunal tubes (NJTs) in children. There are no recommended or published standards of diagnostic reference levels (DRLs) available.

OBJECTIVE

To establish reference dose area product (DAP) levels for the fluoroscopy-guided insertion of nasojejunal tubes as a basis for setting DRLs for children. In addition, we wanted to assess our local practice and determine the success and complication rates associated with this procedure.

MATERIALS AND METHODS

Children who had NJT insertion procedures were identified retrospectively from the fluoroscopy database. The age of the child at the time of the procedure, DAP, screening time, outcome of the procedure, and any complications were recorded for each procedure. As the radiation dose depends on the size of the child, the children were assigned to three different age groups. The sample size, mean, median and third-quartile DAPs were calculated for each group. The third-quartile values were used to establish the DRLs.

RESULTS

Of 186 procedures performed, 172 were successful on the first attempt. These were performed in a total of 43 children with 60% having multiple insertions over time. The third-quartile DAPs were as follows for each age group: 0-12 months, 2.6 cGy cm(2); 1-7 years, 2.45 cGy cm(2); >8 years, 14.6 cGy cm(2). High DAP readings were obtained in the 0-12 months (n = 4) and >8 years (n = 2) age groups. No immediate complications were recorded.

CONCLUSION

Fluoroscopy-guided insertion of NJTs is a highly successful procedure in a selected population of children and is associated with a low complication rate. The radiation dose per procedure is relatively low.

Malposition of feeding tubes in neonates: is it an issue?

OBJECTIVES

Accurate tube placement of orogastric and nasogastric feeding tubes in neonates is important to ensure safe and effective enteral feeding. Errors in placement and position of feeding tubes are described in literature, but there is little evidence of the exact prevalence of improperly placed tubes, especially in neonates.

MATERIALS AND METHODS

To evaluate the prevalence of improperly placed feeding tubes, we reviewed 381 consecutive radiographs and defined the position of the feeding tubes.

RESULTS

We found that in 41% of the placements, the optimal position of the feeding tubes was achieved, whereas overall 59% of the feeding tubes had been placed incorrectly.

CONCLUSIONS

There is a need for both better rules to measure the distance between nose (lips) and the body of the stomach and improved methods to confirm correct tube position in neonates.

Confirming nasogastric tube position in the emergency department: pH testing is reliable

OBJECTIVE

The aim of this study was to determine whether pH testing is an accurate method of confirming nasogastric tube (NGT) position in children with and without gastroenteritis in the emergency department.

METHODOLOGY

A prospective observational study of NGT insertions was conducted at a tertiary pediatric emergency department, during a 9-month period in 2006. We evaluated methods of NGT position confirmation, pH of nasogastric aspirates from patients with and without gastroenteritis, and adverse events.

RESULTS

A total of 404 patients were enrolled. For 393 patients (97.3%), NGT aspirates could be obtained to assess pH. Of these patients, 294 (74.8%) had a diagnosis of gastroenteritis and 99 (25.2%) did not. There was no difference in median pH between the patients with gastroenteritis (pH, 2; interquartile range, 2-4) and those without gastroenteritis (pH, 2; interquartile range, 2-4; P = 0.09). Overall, 341 patients (86.8%) had a pH of 4 or lower. The patients with gastroenteritis were more likely to have a pH of 4 or lower than the patients without gastroenteritis (P = 0.018). Tube position was confirmed by pH alone in 332 patients (84.5%). Nine (2.6%) of the 341 patients with a pH of 4 or lower also had radiography (7 for causes other than confirmation of NGT position) indicating correct placement of all NGTs. Fifty-two patients (13.2%) had a pH higher than 4, and 18 (34%) of these had the tube position confirmed by radiography, of which 3 had tubes misplaced in the distal esophagus. Irrespective of pH level, there were no respiratory placements clinically or by radiography. Overall, 22 patients (5.6% 95% CI 3.5%-8.3%) required more than 1 attempt for NGT insertion. There were 13 minor adverse events (3.3% 95% CI 1.8%-5.6%) and no major adverse events.

CONCLUSIONS

Testing of gastric pH is a reliable way of confirming NGT position when the pH is 4 or lower. When the pH is higher than 4, a radiograph may be necessary.

Pepsin, a marker of gastric contents, is increased in tracheal aspirates from preterm infants who develop bronchopulmonary dysplasia

OBJECTIVE

The objective of this study was to study the association between pepsin in tracheal aspirate samples and the development of bronchopulmonary dysplasia in preterm infants.

METHODS

Serial tracheal aspirate samples were collected during the first 28 days from mechanically ventilated preterm neonates. Bronchopulmonary dysplasia was defined as the need for supplemental oxygen at 36 weeks' postmenstrual age. An enzymatic assay with a fluorescent substrate was used to detect pepsin. Total protein was measured by the Bradford assay to correct for the dilution during lavage. Immunohistochemistry using antibody against human pepsinogen was performed in 10 lung tissue samples from preterm infants.

RESULTS

A total of 256 tracheal aspirate samples were collected from 59 preterm neonates. Pepsin was detected in 234 (91.4%) of 256 of the tracheal aspirate samples. Twelve infants had no bronchopulmonary dysplasia, 31 infants developed bronchopulmonary dysplasia, and 16 infants died before 36 weeks' postmenstrual age. The mean pepsin concentration was significantly lower in infants with no bronchopulmonary dysplasia compared with those who developed bronchopulmonary dysplasia or developed bronchopulmonary dysplasia/died before 36 weeks' postmenstrual age. Moreover, the mean pepsin level was significantly higher in infants with severe bronchopulmonary dysplasia compared with moderate bronchopulmonary dysplasia. The mean pepsin level in tracheal aspirate samples from the first 7 days was also lower in infants with no bronchopulmonary dysplasia compared with those who developed bronchopulmonary dysplasia or developed bronchopulmonary dysplasia/died before 36 weeks' postmenstrual age. Pepsinogen was not localized in the lung tissues by immunohistochemistry.

CONCLUSION

The concentration of pepsin was increased in the tracheal aspirate of preterm infants who developed bronchopulmonary dysplasia or died before 36 weeks' postmenstrual age. Recovery of pepsin in tracheal aspirate samples is secondary to gastric aspiration, not by hematogenous spread or local synthesis in the lungs. Chronic aspiration of gastric contents may contribute in the pathogenesis of bronchopulmonary dysplasia.

Complications related to feeding tube placement

PURPOSE OF REVIEW

Blind placement of a feeding tube can result in serious complications. Given the widespread use of tube feedings, even a small percentage of such problems can affect a significant number of people. The purpose of this review is to describe recent reports of feeding tube placement problems and to examine possible solutions.

RECENT FINDINGS

Multiple case reports of complications of malpositioned feeding tubes continue to surface; most are due to inadvertent placement in the respiratory tract. A tube with feeding ports in the esophagus significantly increases risk for aspiration, as does the displacement of a small bowel tube into the stomach of a patient with significantly slowed gastric motility. Isolated reports of a nasally placed tube entering the brain following head injury continue to occur, as do reports of esophageal and gastric perforation in neonates. A recent study showed that malpositioned tubes are not routinely recorded in risk management databases; it further demonstrated that a comprehensive intervention to reduce complications from small-bore nasogastric feeding tubes was effective.

SUMMARY

Complications related to malpositioned feeding tubes are usually preventable. Poor reporting of feeding tube placement errors hinders the adoption of effective protocols to prevent such errors.

An evidence-based approach to nasogastric tube management: special considerations

Although there have been helpful literature reviews on pediatric nasogastric (NG) tube management, there is a lack of evidence with regards to special circumstances, such as at-risk patients with altered neurological status or developmental disabilities. At our hospital, an interdisciplinary Enteral Feeding Task Force was created to address the special needs and concerns of complex pediatric patients. We carefully weighed the evidence from the literature, incidents at our hospital and other children's hospitals, and a synthesis of expert opinion. This article describes our evidence-based process of policy revision, and it includes excerpts from our revised NG tube management policy.

Pepsin, a reliable marker of gastric aspiration, is frequently detected in tracheal aspirates from premature ventilated neonates: relationship with feeding and methylxanthine therapy

OBJECTIVES

To determine the frequency of pepsin detection in tracheal aspirate (TA) samples of mechanically ventilated premature neonates and its association with feedings and methylxanthine therapy.

PATIENTS AND METHODS

Serial TA samples (days 1, 3, 5, 7, 14, 21, 28 and >28 days) were collected from premature neonates receiving ventilatory support. An enzymatic assay with a fluorescent substrate was used to detect pepsin. Pepsin was also measured in 10 serum samples collected in conjunction with the TA samples from 8 neonates.

RESULTS

A total of 239 TA samples was collected from 45 premature neonates (mean birth weight, 762 +/- 166 g; mean gestational age, 25.5 +/- 1.5 wk). Pepsin was detectable in 222 of 239 TA samples (92.8%) and in none of the serum samples. Pepsin was significantly lower on day 1 (mean, 170 +/- 216 ng/mL) when compared with all other time points (P < 0.05). Mean concentration of pepsin was significantly lower when infants were unfed (265 +/- 209 ng/mL) compared with levels during feeding (390 +/- 260 ng/mL, P = 0.02). The mean level of pepsin was significantly higher in infants during xanthine therapy (419 +/- 370 ng/mL) compared with no xanthine therapy (295 +/- 231 ng/mL, P = 0.037).

CONCLUSION

Pepsin, a marker of gastric contents, was detected in more than 92% of TA samples from premature infants on mechanical ventilation. The level of pepsin was higher in fed infants when compared with unfed infants. Xanthine therapy was also associated with increased pepsin in TA samples. Chronic aspiration of gastric contents may worsen lung disease in premature infants.

Important Facts About Intestinal Feeding Tube Placement

Enteral feeding is desirable when the gastrointestinal tract is functional because it allows better use of nutrients, is safer, and is more cost-effective than parenteral nutrition. Feeding through a gastric tube, however, is often not feasible in severely ill adults and children because of gastric paresis leading to recurrent episodes of gastroesophageal reflux with the risk of subsequent aspiration. Feeding into the small intestine (duodenum or jejunum) through a nasointestinal tube, therefore, is preferred. Unfortunately, no method of enteral feeding is risk free. This literature review addresses the following 10 topics: (a) the reasons why nasointestinal tube feeding is better tolerated by some patients, (b) candidates for nasointestinal tube feeding, (c) options for selecting nasointestinal tubes, (d) recommended methods for predicting the distance to insert nasointestinal tubes, (e) recommended methods for placing nasointestinal tubes, (f) how promotility medications work and whether they facilitate nasointestinal tube placement, (g) nasointestinal tube placement error rate, (h) methods of determining the internal location of nasointestinal tubes, (i) complications associated with nasointestinal tube use, and (j) other pertinent issues surrounding feeding through nasointestinal tubes. The available research evidence is summarized and recommendations for future work are suggested.

Evaluation of a technique for blind placement of post-pyloric feeding tubes in intensive care: application in patients with gastric ileus

OBJECTIVE

To evaluate a blind 'active' technique for the bedside placement of post-pyloric enteral feeding tubes in a critically ill population with proven gastric ileus.

DESIGN AND SETTING

An open study to evaluate the success rate and duration of the technique in cardiothoracic and general intensive care units of a tertiary referral hospital.

PATIENTS

20 consecutive, ventilated patients requiring enteral nutrition, where feeding had failed via the gastric route.

INTERVENTIONS

Previously described insertion technique-the Corpak 10-10-10 protocol-for post-pyloric enteral feeding tube placement, modified after 20 min if placement had not been achieved, by insufflation of air into the stomach to promote pyloric opening.

MEASUREMENTS AND RESULTS

A standard protocol and a set method to identify final tube position were used in each case. In 90% (18/20) of cases tubes were placed on the first attempt, with an additional tube being successfully placed on the second attempt. The median time for tube placement was 18 min (range 3-55 min). In 20% (4/20) insufflation of air was required to aid trans-pyloric passage.

CONCLUSIONS

The previously described technique, modified by insufflation of air into the stomach in prolonged attempts to achieve trans-pyloric passage, proved to be an effective and cost efficient method to place post-pyloric enteral feeding tubes. This technique, even in the presence of gastric ileus, could be incorporated by all critical care facilities, without the need for any additional equipment or costs. This approach avoids the costs of additional equipment, time-delays and necessity to transfer the patient from the ICU for the more traditional techniques of endoscopy and radiographic screening.

Litmus tests for verification of feeding tube location in infants: evaluation of their clinical use

AIMS

To examine the clinical use of litmus paper tests for the assessment of aspirates in infants.

BACKGROUND

In connection with establishing a programme for home care of infants with requirement of tube feeding with parents as the infants' carers, the need for a research-based method for verification of feeding tube position was identified by nurses as a complement to other methods. In adult care the litmus paper test is commonly used when visual inspection is not sufficient for assessment of aspirates obtained from feeding tubes.

DESIGN

Observational study.

METHODS AND MATERIAL

Nurses performed litmus tests for verification of feeding tube location in a convenience sample of 60 infants born at a gestational age (GA) of 24-42 weeks. Presence/absence and volumes of aspirates were recorded as well as positive/negative litmus test reactions. Analyses on the association between test results and the infants' GA and postmenstrual and postnatal age at the time of the tests were conducted.

RESULTS

Data were obtained from 2970 tube feeds. Aspirates were present on 1840 occasions (62%). A higher proportion of infants with absence of aspirates were born at a GA below 32 weeks. A positive reaction occurred in 97% of the tests in volumes between 0.01 and 22 ml. Birth at a GA below 32 weeks and respiratory problems were associated with negative tests.

CONCLUSION

The high ratio of positive litmus reactions at all maturational levels supports the bedside use of analysis of pH in gastric aspirates for verification of feeding tube location.

RELEVANCE TO CLINICAL PRACTICE

Application of pH indicator paper is recommended as a complementary method for assessment of aspirates from feeding tubes.

Nutrición artificial en las unidades de cuidados intensivos pediátricos

OBJECTIVE

To perform an epidemiologic study of artificial nutrition in critically-ill pediatric patients.

PATIENTS AND METHODS

A multicenter, prospective and descriptive study was conducted in 23 Spanish intensive care units (ICU) (18 pediatric ICUs and five pediatric/neonatal ICUs) over a 1-month period. Artificial nutrition (AN) was required by 165 critically-ill patients (21.4 %). Data on diagnosis, severity, treatment, type of nutrition administered and complications were analyzed.

RESULTS

A total of 54.4 % of the participants were younger than 1 year, 19.4 % were aged between 1 and 5 years old, 15.7 % between 5 and 10 years old and 13.4 % were older than 10 years. ICU mean length stay was 11 days. One hundred six patients were administered enteral nutrition (EN): 67.9 % continuous nasogastric EN, 27.4 intermittent nasogastric EN, 16 % nasojejunal EN, 2.8 % gastrostomy EN. Eighty patients required parenteral nutrition (PN): 86.3 % central PN, 20 % peripheral PN. No significant differences were found between patients with EN and PN in mean energy intake, days receiving AN, diagnosis at admission to the ICU, disease severity (measured by PRISM III) or intensive support techniques. The EN group required greater inotropic support. Patients undergoing mechanical ventilation had equal mortality independent of the type of AN. The most common complications in EN were: 17.9 % emesis, 13.2 % abdominal distension, 11.3 % diarrhea, 4.7 % gastric residual volumes, and 6.6 % hypokalemia. In PN complications consisted of: 5 % catheter related infection, 1.3 % thrombophlebitis, 7.5 % hyponatremia, 3.8 % hypoglycemia, 6.3 % hypophosphatemia and 3.8 % hypertriglyceridemia.

CONCLUSIONS

EN provides critically-ill children with adequate energy intake and is well tolerated. Therefore, if there are no contraindications, EN should be the system of choice in the critically-ill patient requiring AN.

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.

What Is Known About Methods of Correctly Placing Gastric Tubes in Adults and Children

An abdominal radiograph is considered the "gold standard" for determining the position of flexible small-bore nasogastric/orogastric tubes. However, placement must be checked frequently while a tube is in place, and the summative radiation risk of multiple radiographs, as well as their expense, make the development of adequate bedside placement-locating methods imperative. Several methods of detecting tube placement have been investigated in adults, including: aspirating gastric contents and measuring the pH, bilirubin, pepsin, and trypsin levels; examining the visual characteristics of aspirate; placing the proximal end of the tube under water and observing for bubbles in synchrony with expirations; measuring the carbon dioxide level at the proximal end of the nasogastric/orogastric tube; auscultation for a gurgling sound over the epigastrium or left upper quadrant of the abdomen; and measuring the length from the nose/mouth to the proximal end of the tube. Many researchers have already concluded simple auscultation is not a reliable method to assess tube position because injection of air into the tracheobronchial tree or into the pleural space can produce a sound indistinguishable from that produced by injecting air into the gastrointestinal tract. In adults, only pH and bilirubin of aspirate have been shown both to reliably predict tube position and to have inexpensive simple bedside tests. In children, only pH of aspirate has been shown to be reliable. Research on gastric tube placement in children is relatively new because children are challenging to study in that they are considered a vulnerable population. This review of the literature includes results of both adult and pediatric studies. Tube placement error rates varied from 1.9% to 89.5% in adults and between 20.9% and 43.5% in children.

Methods to Test Feeding Tube Placement in Children

PURPOSE

This replication study examined the extent to which feeding-tube aspirates (pH and enzyme content) are effective predictors of feeding tube location in acutely ill children.

STUDY DESIGN AND METHODS

A convenience sample of 56 children was obtained at a metropolitan children's hospital. Approximately 2.5 ml of fluid were withdrawn from children's nasogastric, orogastric, or nasointestinal tubes within 30 minutes of radiographic examination. Fluid was tested for pH and enzymes, and results were compared with radiographic results of tube location.

RESULTS

Mean gastric pH was significantly lower than mean intestinal pH. Mean fasting gastric pepsin level was significantly higher than mean fasting intestinal pepsin level. Usual intestinal constituent, trypsin, was significantly higher in the small bowel than in the stomach. Mean fasting trypsin level was 70 microg/ml in the intestine, and only 10 microg/ml in the gastric site. Predictive positive value was >90% for all tests; predictive negative value was < 65%. Colors of the gastric aspirates were distinctly different from those observed in intestinal aspirates.

CLINICAL IMPLICATIONS

Methods of aspirating fluid from feeding tubes and testing visually or assaying for aspirate characteristics were found to be adaptable from adults to children. The clinical implications of being able to use a test as simple as pH of feeding aspirates means that nurses can easily test these aspirates in any clinical setting using reliable pH test strips, similar to what was done in this study. These data add evidence that suggests indicators of tube location effective in adults are also effective in children.

The pragmatics of feeding the pediatric patient with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents the ultimate pulmonary response to a wide range of injuries, from septicemia to trauma. Optimal nutrition is vital to enhancing oxygen delivery, supporting adequate cardiac contractility and respiratory musculature, eliminating fluid and electrolyte imbalances, and supporting the proinflammatory response. Research is providing a better understanding of nutrients that specifically address the complex physiologic changes in ARDS. This article highlights the pathophysiology of ARDS as it relates to nutrition, relevant nutritional assessment, and important enteral and parenteral considerations for the pediatric patient who has ARDS.

Intravenous erythromycin facilitates bedside placement of postpyloric feeding tubes in critically ill adults: a double-blind, randomized, placebo-controlled study

OBJECTIVE To evaluate the efficacy of intravenous erythromycin as a method to facilitate feeding tube placement into the small intestine in critically ill patients. DESIGN Double blind, randomized, controlled trial. SETTING Medical and surgical intensive care units in an academic medical center. PATIENTS Prospective cohort of 36 consecutive adults requiring intensive care unit care and enteral tube feeding for nutritional support. INTERVENTION Infusion of a single dose of intravenous erythromycin (500 mg) or saline before placement of 10-Fr feeding tubes using a standardized active bedside protocol. MEASUREMENTS AND MAIN RESULTS We determined the success rate of feeding tube placement into or beyond the second portion of the duodenum and the time required for this procedure by experienced nurses. The feeding tube was considered to be postpyloric when the tip was in the second portion of the duodenum or beyond. The predictive value of a serial step-up in gastrointestinal aspirate pH from < or = 5.0 to > or = 6.0 was also determined. Use of intravenous erythromycin significantly improved the rate of feeding tube placement into the duodenum or jejunum (erythromycin group, 13 of 14 patients or 93% vs. the control group, 12 of 22 patients or 55%; p < .03). Erythromycin administration also significantly decreased the procedure time from 25 +/- 3 to 15 +/- 2 mins (p < .04). Feeding tube placement into either duodenum or jejunum was confirmed in all 18 patients with a pH step-up from < or = 5.0 to > or = 6.0.

CONCLUSION

A single bolus dose of intravenous erythromycin facilitates active bedside placement of postpyloric feeding tubes in critically ill adult patients.

Nutritional support in the critically ill child

The nutritional management of a critically ill child is not a glamorous subject and seldom receives the attention that it merits despite increasing evidence that appropriate goal-oriented nutritional support is associated with improved outcome. Current nutritional management is based on rapidly emerging knowledge on the very special nutritional requirements related to the "vastly different metabolic and physiologic characteristics of the hypermetabolic and stressed" critically ill child. There has been significant changes in traditional practice particularly in the area of calorie delivery, amount of macronutrients and route of nutrient delivery in the critically ill child. The critically ill child presents with "greatly disordered nutrient metabolism" and successful nutritional support involves an initial "hypocaloric regime" with a precise mix of carbohydrates, proteins and lipids which need periodic review as the child improves. The therapeutic benefits of minimal enteral feeding (MEF) have been clearly established--MEF being associated with diminished morbidity, infection rates as well as reduced ICU and hospital stays. Immune enhancement has also been shown to be of some benefit in the critically ill but the subject needs further study.

Detection of pepsin and glucose in tracheal secretions as indicators of aspiration in mechanically ventilated children

OBJECTIVES

The detection of glucose in tracheal secretions has been used as an indicator of aspiration in mechanically ventilated, tube-fed children. Pepsin detection may be a more specific indicator. We determined the frequency of pepsin and glucose detection in tracheal secretions of mechanically ventilated children and studied the relationships between tracheal secretion pepsin and glucose and clinical evidence of gastroesophageal reflux.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

PATIENTS

A convenience sample of mechanically ventilated children.

INTERVENTIONS

Tracheal secretions were collected at the time of routine endotracheal tube suctioning. Tracheal aspirate glucose concentrations were assessed by using glucose oxidase reagent strips. Tracheal aspirate pepsin was detected by laboratory immunoassay.

MEASUREMENTS AND MAIN RESULTS

One hundred tracheal aspirates were collected from 37 children. Pepsin (>or=1 microg/mL) was detected in nine aspirates, and glucose (>or=20 mg/dL) was detected in 59 aspirates. Overall, five (13.5%) patients had at least one pepsin-positive aspirate, and 33 (89%) had at least one glucose-positive aspirate. Patients with at least one pepsin-positive aspirate were more likely to have clinical evidence of gastroesophageal reflux than patients with pepsin-negative aspirates (5 of 5 vs. 9 of 32, p <.01, Fisher's exact test). Tracheal aspirate glucose positivity was unrelated to the administration of tube feedings and gastroesophageal reflux. No relationship between pepsin and glucose positivity was observed.

CONCLUSIONS

Pepsin is detectable in tracheal secretions of mechanically ventilated children at risk for aspiration. Elevated glucose concentrations in tracheal secretions can occur by mechanisms other than aspiration of glucose-rich formula. Pepsin may be a more specific marker for aspiration than glucose.

Efficacy of erythromycin for postpyloric placement of feeding tubes in critically ill children: a randomized, double-blind, placebo controlled study

BACKGROUND

Erythromycin enhances gastric emptying and has been suggested to facilitate nasoenteric feeding tube placement in adults. Our primary objective was to evaluate the effect of erythromycin on the transpyloric passage of feeding tubes in critically ill children, and second, to evaluate the effect of erythromycin on the distal migration of duodenal feeding tubes.

METHODS

Seventy-four children were randomly assigned to receive erythromycin lactobionate (10 mg/kg) IV or equal volume of saline placebo 60 minutes before passage of a flexible weighted tip feeding tube. Abdominal radiographs were obtained 4 hours later to assess tube placement. If the tube was proximal to the third part of the duodenum, two additional doses of erythromycin/placebo were administered 6 hours apart. Those receiving additional doses had repeat radiographs 14 to 18 hours after tube placement.

RESULTS

The number of postpyloric feeding tubes was similar in the erythromycin and placebo treated groups 4 hours after tube insertion (23/37 vs 27/37, p = .5). Of those with prepyloric tubes at 4 hours, none in the erythromycin group and 3 in the placebo group had the tube migrate to the postpyloric position by 14 to 18 hours (p < .05). Of those with postpyloric tubes proximal to the third part of the duodenum at 4 hours, additional doses of erythromycin did not cause more tubes to advance further into the intestine than did placebo (p = .6).

CONCLUSIONS

Erythromycin does not facilitate transpyloric passage of feeding tubes in critically ill children. The distal migration of duodenal tubes further into the small bowel is also not enhanced by erythromycin.

Feeding the intensive care patient

The present review highlights recent findings (focusing on papers published between October 1999 and December 2000) in nutritional support of intensive care unit patients. During the past year, research focused on the use of enteral nutrition versus parenteral nutrition, and on the best composition of enteral nutrition and parenteral nutrition according to the clinical condition of the patient. With regard to enteral nutrition, the pH of nutritional support, the timing of administration and the technique of tube placement were debated. Immunomodulating agents and hormonal manipulations may improve outcomes of critically ill patients, but still warrant further research before they can be recommended for routine clinical use.