Improved design of nasogastric feeding tubes

Disappointed with the overall performance of weighted and unweighted nasogastric feeding tubes, a design programme was initiated which resulted in the development of two new nasogastric tubes, one weighted and one unweighted. The tubes were manufactured with polyurethane rather than polyvinylchloride (PVC) which permitted an increase in diameter of the internal lumen which in turn was coated with water activated lubricant to ease removal of the introducer wire. A specially modelled outflow port was incorporated into the tips of both tubes. The performance of the two new polyurethane nasogastric feeding tubes was assessed under controlled trial condition using as a reference a widely used PVC unweighted open ended tube. While intubation times were similar in patients without concurrent endotracheal intubation, it took a significantly shorter time to intubate patients with concurrent endotracheal intubation with the new weighted tube. Following tube intubation, it was possible to aspirate gastric contents significantly more often through the new polyurethane tubes (p < 0.001) than through the PVC tube, and the unweighted polyurethane tube stayed in situ longer (p < 0.05) than the PVC tube. The newly designed polyurethane nasogastric feeding tubes are the first tubes that have been shown to have advantages over the simpler type of open ended, unweighted PVC nasogastric feeding tubes.     

Clinical evaluation of a newly designed nasogastric enteral feeding tube

Concerned with reports in the literature of a rising incidence of enteral feeding tube clogging, we initiated a design programme in an attempt to improve the clinical efficacy of nasogastric and nasoenteric enteral feeding tubes. Tube design has been based on a remodelling of the outflow part of a polyurethane feeding tube previously developed in our unit. The tip of the newly designed 8F enteral feeding tube is shorter in length with a rounded end to minimize discomfort during intubation. The port itself incorporates a tapered outflow design with the side walls now extending below the mid-point of the internal flow lumen resulting in a 28% increase in port area compared to the equivalent and originally designed tube. The performance of the newly designed polyurethane feeding tube was assessed under controlled trial conditions using as references two widely used 8F polyurethane nasogastric feeding tubes whose design has been based on different principles (Flexiflo, weighted tip, open-ended with two side ports; Freka, occluded tip, two simple large side ports). Eighty-eight of 90 patients entered into the study were successfully intubated with no significant differences being noted in intubation times in the three groups. Significantly less discomfort occurred during intubation of patients with the Radius tube as compared to the Freka tube (P < 0.05). Although there were no clear differences between the Flexiflo and Freka tubes either in regard to the number of attempts required for intubation or aspiration or discomfort during intubation or ease of aspiration, fewer attempts at insertion and aspiration were needed and intubation and aspiration were easier for patients randomised to the Radius group than those to the Flexiflo and Freka groups (P < 0.05). We conclude that the clinical performance of the newly designed Radius enteral feeding tube compares favourably with that of the reference tubes. Only one of the new tubes (3.3%) blocked during the course of the study. High rates of non-elective extubation were observed in the three study groups (Radius 80.0%, Flexiflo 73.3%, Freka 73.3%). Design modifications are unlikely to influence non-elective nasogastric feeding tube extubation rates which remain a major clinical problem.     

Limitations and drawbacks of 'fine bore' nasogastric feeding tubes

The clinical use of unweighted nasogastric feeding tubes (n = 491) was compared with that of weighted nasogastric feeding tubes. No advantage was found in the use of the weighted tubes.     

7 g weighted versus unweighted polyurethane nasoenteral tubes--spontaneous transpyloric passage and clinical performance: a controlled randomised trial

A proportion of patients requiring enteral nutrition is at increased risk of regurgitation or pulmonary aspiration of enteral diet as a result of gastric atony or paresis. The positioning of the distal end of an enteral feeding tube beyond the pylorus into duodenum or jejunum may reduce this risk. It has been postulated that by suitable lengthening of feeding tubes and by altering the distal end tip profile or by the addition of a weight, spontaneous passage of a tube through the pylorus after pernasal insertion may be achieved. In a recent controlled trial we were unable to demonstrate any advantage to a) modifying the tip profile or b) the addition of a 2.4 g weight. This prospective controlled clinical study examined the difference between an unweighted polyurethane tube which had performed optimally in the previous study and a new 7 g weighted tube similar in all other respects. In both cases less than 50% of tubes had passed spontaneously through the pylorus when assessed at 24 h, with no significant difference in performance (p = 0.38). When comparing overall length of time that each tube remained in situ, there was similarly no significant difference between the 7 g weighted and unweighted tubes (p = 0.277). We conclude that the addition of a 7 g weight to a suitably lengthened enteral feeding tube confers no advantage on either incidence of spontaneous transpyloric passage or in prolonging tube usage. If post-pyloric feeding is indicated for a patient, positioning by either fluoroscopic or endoscopic techniques should be undertaken.     

Clinical indications for weighted enteral feeding tubes

Simple unweighted fine bore feeding tubes have been used by our Nutritional Support Team for routine nasogastric feeding with success in large numbers of patients. Three clinical situations where mercury or tungsten weighted tubes offer advantages over fine bore tubes have been defined. Significant advantages in patients with concurrent endotracheal intubation, gastric atony and severe oesophageal stricturing are described.     

Spontaneous transpyloric passage and performance of 'fine bore' polyurethane feeding tubes: a controlled clinical trial

Certain groups of patients requiring enteral nutritional support are at increased risk of regurgitation and pulmonary aspiration of feed. Positioning of enteral feeding tubes distal to the pylorus has been advocated as a method of reducing such complications. Various techniques have been suggested to achieve postpyloric siting. Reports have indicated that lengthening the tube or altering the distal end tip configuration, by varying the tip profile or by the addition of a weight, may facilitate spontaneous transpyloric passage of the tube. This prospective controlled clinical study using three new polyurethane tubes demonstrates that the frequency of spontaneous transpyloric passage of the tube is not affected by tip profile or by the addition of a weight. Indeed, with all three tube designs only about one-third had passed spontaneously through the pylorus at 24 hr. Once through the pylorus the unweighted tube stayed in position significantly longer than the weighted tubes (p less than 0.005). We suggest that in those patients requiring post-pyloric feeding, endoscopic or fluoroscopic techniques should be used to position the tubes at the time of insertion, and that an unweighted tube should be used to prolong tube usage.     

Dual‐Purpose Gastric Decompression and Enteral Feeding Tubes Rationale and Design of Novel Nasogastric and Nasogastrojejunal Tubes

Background: The importance of early postoperative nutrition in surgical patients and early institution of enteral nutrition in intensive care unit (ICU) patients have recently been highlighted. Unfortunately, institution of enteral feeding in both groups of patients often has to be postponed due to delayed gastric emptying and the need for gastric decompression. The design of current polyvinylchloride (PVC) gastric decompression tubes (Salem Sump [Covidien, Mansfield, MA] in the United States; Ryles [Penine Health Care Ltd, Derby, UK] in the United Kingdom and Europe) make them unsuitable for their subsequent use as either nasogastric enteral feeding tubes or for continued gastric decompression during postpyloric enteral feeding. To overcome these problems, we have designed a range of polyurethane (PU) dual‐purpose gastric decompression and enteral feeding tubes that include 2 nasogastric tubes (double lumen to replace Salem Sump; single lumen to replace Ryles). Two novel multilumen nasogastrojejunal tubes (triple lumen for the United States; double lumen for the United Kingdom and Europe) complete the range. By using PU, a given internal diameter (ID) and flow area can be incorporated into a lower outside diameter (OD) compared with that achieved with PVC. The ID and lumen and flow area of an 18Fr (OD 6.7 mm) PVC Salem Sump can be incorporated into a 14Fr (OD 4.7 mm) PU tube. The design of aspiration/infusion ports of current PVC and PU tubes invites occlusion by gastrointestinal mucosa and clogging by mucus and enteral feed. To overcome this, we have designed long, single, widened, smooth, and curved edge ports with no “dead space” to trap mucus or curdled diet. Involving up to 214° of the circumference, these ports have up to 11 times the flow areas of the aspiration ports of current PVC tubes. Conclusion: The proposed designs will lead to the development of dual‐purpose nasogastric and nasojejunal tubes that will significantly improve the clinical and nutrition care of postoperative and ICU patients.     

Do weighted nasoenteric feeding tubes facilitate duodenal intubations?

A widely held assumption is that postpyloric intubations occur more often with weighted than with unweighted nasally inserted feeding tubes. This randomized, prospective study compared the frequency of duodenal intubations using weighted and unweighted nasoenteric feeding tubes. One hundred sixteen patients had either weighted (61 patients) or unweighted (55 patients) 10F silicone elastomer feeding tubes inserted nasally 85 cm. Tubes were placed with wire stylets. Tube positions were verified radiographically within 4 hr after insertions. Radiographs were repeated daily for 3 days or until duodenal intubation occurred. Successful duodenal intubations were achieved in 35 patients (57%) with weighted feeding tubes and in 37 patients (67%) with unweighted feeding tubes. This difference was not significant. Weighted nasoenteric feeding tubes offer no advantage over unweighted tubes in achieving duodenal intubations.     

Lung perforation by nasogastric feeding tubes

Endotracheal misdirection of narrow bore nasogastric feeding tubes resulted in perforation of the lung, pneumothorax and hydrothorax in two intensive care patients. Both were intubated with cuffed endotracheal low pressure tubes, one patient was on respirator therapy with neuromuscular relaxation. Feeding tubes were inserted by experienced personnel with the assistance of a steel stylet without difficulties. Aspiration of fluid was misinterpreted as proof of correct positioning, the liquid being however pleural effusion and not gastric juice. Similarly auscultation of gurgling sounds in the upper epigastrium was not a reliable sign of intragastric position. Insertion of nasoenteric feeding tubes may be complicated by perforation of the upper gastrointestinal tract and lung in poorly responsive patients with cuffed endotracheal devices during neuromuscular blockage. In these patients a laryngoscope and forceps should be used to ensure free passage of the tube into the oesophagus. R?ntgenographic confirmation of correct positioning of the tube immediately after insertion is mandatory.     

Endoscopic placement of fine bore nasogastric and nasoenteric feeding tubes

In a small proportion of patients requiring enteral nutrition it may not be possible to site nasogastric or nasoenteric feeding tubes using standard intubation techniques. We describe an endoscopic method of tube placement applicable not only for positioning nasogastric feeding tubes in patients with coexisting oesophageal pathology, but also for placement of nasoenteric feeding tubes when disordered gastric emptying is present.     

When Does Metoclopramide Facilitate Transpyloric Intubation?

Postpyloric feeding probably reduces the incidence of tracheobronchial aspiration and improves feeding tolerance. However, duodenal intubation is often unsuccessful in critically ill patients due to gastric atony. Metoclopramide improves gastric emptying. In a pilot study, 12 adult patients were administered 10 to 20 mg of intravenous metoclopramide after weighted nasal feeding tubes had failed to spontaneously pass distal to the pylorus. In no patient did metoclopramide induce transpyloric passage of the tube. A randomized prospective study involving 10 adult patients was conducted to examine the effect of preinsertion intravenous metoclopramide on transpyloric intubation. All patients had failed to achieve spontaneous duodenal intubation. Five patients received 20 mg of metoclopramide 10 min prior to nasal insertion of a weighed feeding tube. Five control patients received no premedication. Four metoclopramide patients achieved duodenal intubation immediately. In none of the control patients did transpyloric intubation occur (p = 0.048). Metoclopramide, administered after nasogastric intubation, is ineffective in promoting transpyloric advancement of feeding tubes. There is a significant increase in transpyloric intubation when metoclopramide is administered prior to tube insertion.     

Nasoenteral feeding tube insertion via fiberoptic endoscope for enteral hyperalimentation.

Total parenteral nutrition can maintain good nutritional status in selected patients. However, it can be accompanied by serious complications. It is generally agreed that enteral alimentation is more economical and safer. Gut should be used for nutritional replenishment whenever feasible. However, large-bore nasogastric feeding tubes can cause problems. Even fine-bore nasogastric tubes can cause aspiration pneumonia in obtunded and debilitated patients. In some patients it is clearly desirable to have the tip of the feeding tube in the distal duodenum or proximal jejunum. Previously described methods for placement of nasoenteral tubes may be unsatisfactory. We describe a safe, simple, and reliable method for endoscopic insertion of fine-bore nasoenteral feeding tube. We have used this method on 15 patients without complication.     

Prospective study of nasogastric feeding via East Grinstead or Viomedex tubes compared with oral dietary supplementation in patients with cirrhosis

Forty-seven patients with alcoholic hepatitis and/or cirrhosis were randomised to receive nutritional supplementation by oral sip feeding or by nasogastric infusion administered via either an East Grinstead or a Viomedex nasoenteric tube. The three groups were well matched for severity and complications of liver disease. Patients fed by the nasogastric route attained their daily target dietary intake significantly more often than did those supplemented orally, but the consequent improvement in their nitrogen balance was not significant. There were no significant differences between nasogastric and sip feeding, or between the types of tube studied, in the frequency with which vomiting, diarrhoea or variceal bleeding occurred, but Viomedex tubes required reinsertion significantly less frequently than did the East Grinstead type.     

Nasoenteric feeding tubes in critically ill patients (fluoroscopy versus blind)

Numerous complications have been encountered with small-bore nasoenteric feeding tubes, some potentially life threatening. Patients particularly at risk are those with anatomic abnormalities, debilitation, or neurologic impairment. Fluoroscopy has been reported to be a safe, efficacious modality for the placement of these tubes. Thirty critically ill patients were studied to assess caloric delivery, costs, and complications associated with both fluoroscopically and blindly placed feeding tubes. All patients had either a tracheostomy or an endotracheal tube. They were randomized to group A (fluoroscopy) or group B (blind). Caloric delivery was greater in group A patients on days 1 through 5, with statistically significant differences on days 1 through 4. The mean daily calories per patient over the study period was 1135 +/- 96 and 662 +/- 110 (mean +/- SEM) in groups A and B, respectively (P < 0.01). Costs were similar in both groups. The most frequent problems encountered were difficult insertion, tubes requiring replacement, and failure to intubate the duodenum. We conclude that critically ill patients intubated either endotracheally or with tracheostomy should have nasoenteric feeding tubes placed with the guidance of fluoroscopy.     

Pneumothorax following attempted nasogastric intubation for nutritional support

Nasogastric intubation is a routine procedure, performed daily by both medical and nursing staff. It is a simple procedure, but not without complications which can be life threatening. We present an unusual, life threatening complication which occurred when nasogastric intubation using a no. 8 polyurethane tube with its metal stilet resulted in a pneumothorax after intubation of the endotracheal tree in the presence of a cuffed endotracheal tube. We emphasize that the presence of a cuffed endotracheal tube should not be considered a safeguard against pulmonary intubation during nasogastric placement of a feeding catheter.     

Implementation of an electromagnetic imaging system to facilitate nasogastric and post-pyloric feeding tube placement in patients with and without critical illness

Background:  Artificial nutrition support is required to optimise nutritional status in many patients. Traditional methods of placing feeding tubes may incur clinical risk and financial costs. A technique facilitating placement of nasogastric and post-pyloric tubes via electromagnetic visual guidance may reduce the need for X-ray exposure, endoscopy time and the use of parenteral nutrition. The present study aimed to audit use of such a system at initial implementation in patients within an acute NHS Trust.
Methods:  A retrospective review was undertaken of dietetic and medical records for the first 14 months of using the Cortrak® system. Data were collected on referral origin, preparation of the patient prior to insertion, placement success rates and need for X-ray. Cost analysis was also performed.
Results:  Referrals were received from primary consultants or consultant intensivists, often on the advice of the dietitian. Fifty-nine percent of patients received prokinetic therapy at the time of placement. Thirty-nine tube placements were attempted. Sixty-nine percent of referrals for post-pyloric tube placement resulted in successful placement. X-ray films were requested for 22% of all attempted post-pyloric placements. Less than half of nasogastric tubes were successfully passed, although none of these required X-ray confirmation. The mean cost per tube insertion attempt was £111.
Conclusions:  This system confers advantages, particularly in terms of post-pyloric tube placement, even at this early stage of implementation. A reduction in clinical risk and cost avoidance related to X-ray exposure, the need for endoscopic tube placement and parenteral nutrition have been achieved. The implementation of this system should be considered in other centres.     

Influence of unclogging agents on the surface state of enteral feeding tubes

Background: Despite standardized prevention procedures, recalcitrant clogging of enteral feeding tubes is observed, which requires recourse to varied unclogging agents. Some of these agents have proved effective in routine use, but their impact on the surface state of the tube materials has never been studied. In this work, the authors tested the impact of different unclogging agents on the materials used for these tubes (polyurethane and silicone). Methods: Enteral feeding tubes were placed in contact with different agents in vitro, and the surface state of the material was analyzed using 2 different methods: infrared spectroscopy and scanning electron microscopy. To assess the surface state of the silicone and polyurethane tubes, negative controls (undamaged tubes) and positive controls (deliberately damaged tubes) were used for each type. Results: The infrared spectroscopy method did not reveal any damage to the surface of either the silicone or the polyurethane tubes with either treatment. The test results by scanning electron microscopy showed that orange juice, pineapple juice, and cola had no detrimental action on the tube biomaterials under current conditions of clinical practice. Conclusions: Although some studies have advocated using polyurethane tubes to administer medication, silicone appears to be less vulnerable to damage by the agents tested.     

Quality of Life in a Randomized Trial of Nasogastric Tube Feeding in Acute Pancreatitis

Background: Recent clinical studies have shown that nasogastric tube feeding is safe in the majority of patients with acute pancreatitis. Patient‐reported outcomes are important, but the impact of nasogastric tube feeding on the quality of life has not been investigated. This study aims to compare quality of life between nasogastric tube feeding and nil‐by‐mouth groups during and after hospitalization. Methods: Patient‐reported outcomes were recorded daily in a patient diary during hospitalization. The Abdominal Surgery Impact Scale questionnaire was used to determine patients' quality of life. The patients were then followed up at 1 week and 1, 3, and 6 months after discharge. Results: While 17 patients were randomized to nasogastric tube feeding, 18 were put on nil‐by‐mouth. The overall quality of life and individual domains did not differ significantly between the groups during hospitalization (P = .500) or follow‐up. For the entire cohort, individual quality‐of‐life domains during hospitalization improved significantly, including functional impairment (P < .001), pain (P < .001), sleep (P = .035), and psychological function (P < .001). Quality of life further improved for all patients from time of hospital discharge to 3 (P = .002) and 6 months follow‐up (P < .001) but not to 1 week and 1 month. Conclusions: The use of nasogastric tube feeding, in comparison with nil‐by‐mouth, does not impair patients' quality of life. Given the clinical benefits of nasogastric tube feeding, nasogastric feeding should be considered the first‐line approach in all acute pancreatitis patients requiring enteral nutrition.     

Bedside placement of small bowel feeding tubes in hospitalized patients: a new role for the dietitian

OBJECTIVE: The benefits of enteral nutrition when compared with parenteral nutrition are well established. However, provision of enteral nutrition may not occur for several reasons, including lack of optimal feeding access. Gastric feeding is easier to initiate, but many hospitalized patients are intolerant to gastric feeding, although they can tolerate small bowel feeding. Many institutions rely on costly methods for placing small bowel feeding tubes. Our goal was to evaluate the effectiveness of a hospital-developed protocol for bedside-blind placement of postpyloric feeding tubes. METHODS: The Surgical Nutrition Service established a protocol for bedside placement of small bowel feeding tubes. The protocol uses a 10- or 12-French, 110-cm stylet containing the feeding tube; 10 mg of intravenous metoclopramide; gradual tube advancement followed by air injection and auscultation; and an abdominal radiograph for tube position confirmation. In a prospective manner, consults received by the surgical nutrition dietitian for feeding tube placements were followed consecutively for a 10-mo period. The registered dietitian recorded the number of radiograph examinations, the final tube position, and the time it took to achieve tube placement. RESULTS: Because all consults were included, feeding tube placements occurred in surgical and medical patients in the intensive care unit and on the ward. Of the 135 tube placements performed, 129 (95%) were successfully placed postpylorically, with 84% (114 of 135) placed at or beyond D3. Average time for tube placement was 28 min (10 to 90 min). One radiograph was required for 92% of the placements; eight of 135 (6%) required two radiographs. No acute complications were associated with the tube placements. CONCLUSIONS: Hospitalized patients can receive timely enteral feeding with a cost-effective feeding tube placement protocol. The protocol is easy to implement and can be taught to appropriate medical team members through proper training and certification.     

Bedside placement of nasojejunal tubes: a randomised-controlled trial of spiral- vs straight-ended tubes

BACKGROUND AND AIMS: The success rate of unguided nasojejunal feeding tube insertion is low, thus often requiring endoscopic or radiological assistance. The spiral end of the Bengmark nasojejunal tube is supposed to aid post-pyloric placement, but no comparative trial has been performed. METHODS: Patients requiring nasojejunal feeding were randomised to have either Medicina (straight) or Bengmark (spiral) nasojejunal tube placed after stratification into those with normal gastric emptying or clinical evidence of delayed gastric emptying. Nasojejunal tubes were placed at the bedside in a standard fashion without radiological guidance by the same person for pre- and/or post-operative feeding. Bolus intravenous metaclopromide (10mg) was given prior to insertion in the abnormal gastric emptying group. Abdominal radiographs were obtained at 4 and 24h, and the primary end-point was jejunal placement at 24h. RESULTS: Forty-seven patients were randomised of which 17 (11 straight, 6 spiral) could not tolerate the nasojejunal tube. Of the 30 remaining patients, 16 had normal gastric emptying. In patients with normal gastric emptying, successful placement at 24h was achieved in 78% (spiral tube), vs 14% (straight tube) (P=0.041). In the abnormal gastric emptying group, success rates were 57% and 0%, respectively (P=0.07). CONCLUSION: Spiral nasojejunal tubes are preferable to straight tubes for bedside unguided post-pyloric feeding in patients with normal gastric emptying.