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.     

The roles of lactose and Clostridium difficile in the pathogenesis of enteral feeding associated diarrhoea

This study investigated the influence of the disaccharide lactose on the incidence of clinically significant enteral feeding associated diarrhoea. In this double blind study both groups each of 25 patients were randomised to receive either a lactose containing diet Clinifeed 400 in 25 patients or a lactose free diet Ensure in 25 patients. Diarrhoea occurred with equal frequency in both treatment groups, even in those patients with symptomatic and biochemical evidence of impaired lactose handling. Although the onset of diarrhoea was significantly associated with antibiotic administration (p<0.01), Cl. difficile was not isolated from the stools of any patient with diarrhoea.     

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.     

Blood and urinary amino acids in children receiving total parenteral nutrition

Plasma concentrations and urinary outputs of amino acids were estimated in nineteen patients receiving intravenous hyperalimentation to evaluate the adequacy of dosage and composition of the infusates for the maintenance of normal blood concentrations of essential amino acids. The use of high concentrations of branched chain amino acids seems to be appropriate for valine and isoleucine but not for leucine. The high concentration of cysteine in the infusates used induces a very high urinary excretion of cysteine and cystine and are ineffective to bring the decreased plasma cystine levels back to normal.     

Scanning electron microscopy of the internal wall topography of enteral feeding tubes

A range of commercially available naso-gastric and naso-enteric tubes was examined by scanning electron microscopy (S.E.M.). Surface irregularities in which micro-organisms could become trapped were observed on the internal walls of all the samples. Fine bore tubes which had been perfused for 8 h with a milk based feed experimentally contaminated with Staphylococcus aureus showed patches of residual feed and S. aureus cells on their interior surfaces. The potential hazards of entrapment and/or attachment of micro-organisms to the interior walls of these tubes are discussed.     

Endoscopic placement of enteral feeding tubes

The techniques for placement of feeding tubes using fiberscopes are described and an evaluation of the results obtained in the last 12 months is made. The techniques are discussed and compared with other methods of enteral feeding known at present. It is concluded that placement of feeding tubes by endoscopy can be achieved easily, that it is possible to choose the site of enteric liberation of nutrients under conditions which previously represented contraindications, and that this procedure is free of complications even during long periods of time.     

Pleural complications of nasoenteric feeding tubes

Pliable, small-bore, feeding tubes are inserted frequently in critically ill patients. The use of wire stylets to facilitate passage of these tubes has increased the chances of unrecognized tracheal intubations, particularly in obtunded patients. Five patients with depressed sensoria had inadvertent transbronchial insertions of feeding tubes into their pleural spaces over a 28-month period. The incidence of this complication among intensive care unit patients was 0.3%. Sequellae included pneumothoraces in four patients, pleural effusions in three patients, and pneumonia with a pulmonary abscess in one patient. The presence of cuffed endotracheal tubes did not prevent this complication in patients with depressed cough reflexes. Inexperience of feeding tube insertors may have contributed to pleural intubations in four of the patients. In patients with depressed sensoria, adequate confirmation of feeding tube location in the stomach or duodenum requires both chest and abdominal roentgenograms.     

Overnight nasogastric tube feeding

Overnight nasogastric tube feeding allows the patient freedom for normal daytime activities and exercise, essential components of rehabilitation. In order to avoid disturbed nights through frequent micturition we have kept the volume of feed to a minimum. Two types of feed have been used: 1. A supplementary isosmolar feed containing 1000 kCals in 1 litre. 2. A concentrated low volume (404 mosm/kg) feed supplying 1800 kCals including 60 g of nitrogen in 1 litre. Both were delivered via a fine bore tube (internal diameter 1 mm) by continuous infusion from a 1-1.5 litre reservoir using a rotary pump. Feed 1 was given to 64 undernourished elderly female patients (group 1) with fractured neck of femur, the tube being tolerated by 78%; 47 patients in this group were fed for more than 5 days. Feed 2 was given to 10 patients in hospital (group 2) and 8 patients at home (group 3). Few side effects were encountered, the hyperosmolar feed causing no diarrhoea, nausea or hyperglycaemia, emphasising the importance of osmoles per unit time rather than per unit volume. Voluntary oral intake was neither impaired nor increased during the period of tube feeding in group 1, in whom anorexia and thinness were longstanding. In group 2, with recent onset of anorexia and weight loss, tube feeding disinhibited appetite, resulting in a doubling of voluntary oral intake. Improvement in anthropometric and biochemical nutritional parameters was seen in all patients. Clinical improvements e.g. closure of fistulae were also observed. This paper describes the results of our trial of both these options in patients treated in hospital or at home.     

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.     

Transnasal endoscopic placement of nasoenteric feeding tubes: outcomes and limitations in non-critically ill patients.

Transnasal endoscopic placement of nasoenteric tubes (NETs) has been demonstrated to be useful in the critical care setting, with limited data on its role in non-critically ill patients. The authors collected data on consecutive patients from a non-critical care setting undergoing transnasal endoscopic NET placement. All NETs were endoscopically placed using a standard over-the-guidewire technique, and positions were confirmed with fluoroscopy. Patients were monitored until the removal of NETs or death. Twenty-two patients (median age = 62.5 years, 36.4% female) were referred for postpyloric feeding, with main indications of persistent gastrocutaneous fistula (n = 6), gastroparesis or gastric outlet obstruction (n = 5), duodenal stenosis (n = 6), acute pancreatitis (n = 4), and gastroesophageal reflux after surgery (n = 1). Postpyloric placement of NET was achieved in 19 of 22 (86.3%) patients, with 36.8% tube positions in the jejunum, 47.4% in the distal duodenum, and 15.8% in the second part of the duodenum. NET placement was least successful in cases with duodenal stenosis. NETs remained in situ for a median of 24 days (range, 2-94), with tube dislodgement (n = 3) and clogging (n = 5) as the main complications. NET feeding resulted in complete healing of gastrocutaneous fistulae in 5 of 6 patients and provision of total enteral nutrition in 3 of 4 cases of acute pancreatitis and 9 of 11 cases of gastroparesis or proximal duodenal obstruction. Transnasal endoscopy has a role in the placement of NET in non-critically ill patients requiring postpyloric feeding. However, there are some limitations, particularly in cases with altered duodenal anatomy.     

Clinical efficacy and design changes of "fine bore" nasogastric feeding tubes: a seven-year experience involving 809 intubations in 403 patients

We report here our clinical experiences of "fine bore" nasogastric feeding tubes. Data have been collated over a 7-year period (1978-1985). A total of 403 patients were intubated on 809 occasions. In the first retrospective study, the clinical use of 491 unweighted tubes was compared with that of fifty 3.5-g weighted tubes. No advantage was found in the use of the weighted tubes. In the second prospective controlled clinical trial, these results were confirmed. Forty-six patients were intubated on 76 occasions with an 85-cm open-ended, unweighted nasogastric feeding tube (Prima, Portex UK), and 57 patients were intubated on 79 occasions with a 91-cm 3.0-g weighted tube (Entriflex, Biosearch, Raritan, NJ). Mean duration of placement was similar in each case, and 62% of both types of tubes were inadvertently removed. Without exception, all the tubes remained in the stomach throughout. Disappointed with the similar and overall performance of both types of tubes, we initiated a design program 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 modeled 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 conditions; as a reference, a widely used PVC unweighted open-ended tube was used.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

The effect of continuous enteral tube feeding on various nutritional parameters in patients with disseminated malignant melanoma during intensive chemotherapy

In a prospective study the effect of continuous enteral tube feeding was evaluated on various nutritional parameters in patients with disseminated malignant melanoma during 13 chemotherapy courses employing bleomycin, DTIC, vindesine and actinomycin D. The patients received a quantity of calories according to their pretreatment intake, but complete metabolic equilibrium could not be obtained during chemotherapy. Although the weight/height index remained unchanged, a decrease of serum albumin and prealbumin level occurred during all 13 treatment courses. Transferrin level decreased during 11 of these courses and cholinesterase level during 12. Triceps skinfold thickness and arm muscle circumference diminished equally. Serum prealbumin was the first nutritional parameter to fall during chemotherapy and seems to be a very sensitive indicator of the occurrence of nutritional imbalance. The plasma vitamin C level was low before treatment while during treatment both vitamin C and vitamin A level fell quickly even though the nutritional intake of these vitamins was adequate. We conclude that continuous enteral tube feeding, which is a feasible method of feeding, can to some extent fulfill the nutritional needs of patients treated with intensive chemotherapy.     

Web-based teaching module improves success rates of postpyloric positioning of nasoenteric feeding tubes

Background: Bedside protocols improve success rates of postpyloric nasoenteric tube (NET) placement by nutrition teams and experienced individuals. However, many hospitals require novice practitioners to perform these procedures and often choose fluoroscopy, endoscopy, or newer alternative devices to achieve success. Little is known about the ability to train inexperienced practitioners or the effectiveness of the methods used to implement these protocols. Web‐based learning is a potential tool to improve knowledge and procedural skills. The authors created a self‐directed Web‐based teaching module (WBTM) to educate and standardize placement of postpyloric NETs. Methods: Forty‐three first‐, second‐, or third‐year residents or medical or physician assistant students took pretests for knowledge and confidence surveys, viewed the WBTM, placed NET at the bedside, then took a posttest and confidence survey while awaiting confirmation of tube position by abdominal radiograph. Success was acknowledged if the tip of the NET was beyond the pylorus. A retrospective chart review was used to determine a historical success rate, which was used as a control. Results: Knowledge and confidence significantly improved. Overall success rate of postpyloric NET placement for all participants on first attempt was 74.4% vs 46.7% in the control (P = .005). Improvement occurred in all subgroups, including those with no prior experience, who were successful 70.4% of the time (P = .009). Conclusions: This WBTM is simple to implement, inexpensive, and resource efficient. The improvement in postpyloric NET placement, especially among novice practitioners, demonstrates the benefit and applicability of this method of standardized education.     

Pulmonary complications of 9931 narrow-bore nasoenteric tubes during blind placement: a critical review

Introduction: A critical review of the pulmonary complications associated with blind placement of narrow‐bore nasoenteric tubes (NETs) is discussed. Preventive measures and placement techniques are addressed to decrease patient morbidity and mortality. Methods: A thorough database review was conducted to identify all randomized controlled and retrospective trials specifically addressing pulmonary complications from narrow‐bore NET placement. Five unique studies, comprising more than 9900 NET placements, were identified. On the basis of the literature reviewed, the authors identified 3 major complications associated with blind NET placement: patient mortality directly resulting from NET misplacement, incidence of tracheopulmonary malpositioning, and correlation between NET misplacement and mechanical ventilation. Results: Of the 9931 NET placements reviewed, there were 187 total improper tube placements in the tracheobronchial tree, which translates to a 1.9% mean overall malposition rate. Of these 187 misplacements, there were 35 (18.7%) reported pneumothoraces, at least 5 of which resulted in patient death. NET malpositioning was reported in 13%–32% of subsequent repositioning attempts. This increased risk exposes the patient population to a cumulative mortality from tracheobronchial malpositioning approaching >20%. Unexpectedly, of the 187 total misplacements, 113 (60.4%) of the patients were mechanically ventilated. Conclusions: Practitioners need to be aware of the potential for pulmonary complications associated with blind NET placement. Changes in institutional protocol should be considered to minimize unnecessary risks. As with any procedure, experienced personnel should be primarily used for tube placement and responsible for assisting others with less familiarity to learn the proper methods.     

A comparison of tunnelled and nontunnelled subclavian vein catheters: a prospective study of complications during parenteral feeding

Forty-four silastic catheters in 38 surgical patients, nursed in general surgical wards, were inserted under aseptic conditions by the infraclavicular subclavian route. The catheters were randomly allocated to non-tunnelled (NT) (n = 24) or tunnelled (T) (n = 20) groups. Catheters were removed on completion of intravenous feeding or clinical suspicion of catheter infection, and the catheter tip and blood samples taken through the catheter and from the peripheral vein were cultured. There was no significant difference between the two groups in terms of bacteriological infection (defined as two or more cultures of the same organism), clinical infection (defined by elevated temperature returning to normal after catheter removal) and combined infection (when both bacteriological and clinical infection co-existed). When the number of infected catheters was related to the duration of catheter insertion, the incidence of combined catheter related sepsis was reduced with tunnelling (NT: one infected catheter per 35 catheter days, T: one infected catheter per 89 catheter days). This study highlights the risks of subclavian vein catheterisation and emphasises the difficulties in defining catheter sepsis but suggests that its incidence may be reduced if skin tunnelling is employed.     

Effects of surgery and nutritional support on some lymphocyte and PMN leucocyte functions in man

The purpose of the present study was to evaluate the effect on some leucocyte functions of 1) an elective surgical procedure; 2) nutritional repletion provided by parenteral alimentation (TPN). The rates of cellular proliferation and protein synthesis in lymphocyte cultures were measured by the incorporation of respectively 3H-thymidine and 3H-leucine; both measures were performed without and with additions of mitogenic agents. Random migration and chemotaxis of PMN leucocytes were measured under agarose. In 10 well-nourished patients, both lymphocyte proliferation and protein synthesis in stimulated cultures decreased after elective surgery, respectively by 50% (p < 0.01) and by 32% (p < 0.05) while random migration of PMN leucocytes was increased by 50% (p < 0.02). Stimulated lymphocyte proliferation and protein synthesis measured in 10 nutritionally depleted non-cancer patients prior to TPN were lower in comparison to the values obtained in a control population (respectively p < 0.006 and p < 0.04). These parameters rose progressively during TPN and reached the normal range after 3 weeks. Before TPN, PMN leucocyte random migration was slower in depleted patients than in control subjects; this parameter reached normal values after one week of TPN, while chemotaxis tended to decrease. Both parameters were in the normal range after 3 weeks of TPN. Conclusions 1) an elective operation depresses lymphocyte functions but stimulates PMN leucocyte random migration in well-nourished patients; 2) in depleted patients, previously depressed leucocyte responses are restored within 3 weeks of adequate nutritional support.     

Nutritional and immunological assessment of patients with anorexia nervosa

The nutritional and immunological status of patients with anorexia nervosa was assessed. Anthropometric measurements were found to be lowered as were the serum levels of zinc (p<0.01), copper (p<0.01) and ceruloplasmin (p<0.05) in comparison with the control group. However the serum levels of albumin, pre-albumin, transferrin and retinol binding protein, vitamins A and D and leucocyte vitamin C were generally found to be within normal limits. Lymphocyte transformation was measured in response to stimulation with the mitogens Con A, PHA and PWM. Responses were normal in all patients with the exception of one who showed a depressed response to Con A. Natural killer cell activity was measured against the target cell line K562 and was not found to differ significantly from controls. It is suggested that the relatively normal protein and vitamin status is responsible for maintaining the apparently normal cellular immune function in patients with anorexia nervosa.     

Causes of anergy in the surgical patient and its relationship to postoperative sepsis

Between June 1981 and June 1983 the delayed hypersensitivity response (DHR) was studied in 401 patients considered for major surgical procedure: 320 of these patients underwent surgery. The incidence of sepsis and postoperative mortality was higher in anergic and relative anergic patients than in normal responders (p<0.001). To evaluate whether DHR depression in cancer patients was due to the direct effect of cancer or to tumour-linked malnutrition, the 401 patients were divided into 4 groups: 1) 140 malnourished cancer patients, 2) 51 malnourished non-cancer patients, 3) 120 well-nourished cancer patients and 4) 90 well-nourished non-cancer patients. The mean age was not significantly different for the 4 groups. The results showed a relationship between DHR and nutritional status (p<0.001). The tumour-related DHR impairment disappeared when the cancer and non-cancer patient groups were homogeneous with regard to their nutritional status. Therefore, the tumour was able to determine the DHR depression because of the cancer-linked malnutrition. We did not observe any relationship between local extension of the tumour and lymph node involvement and DHR depression. In 90 well-nourished non-cancer patients the relation between DHR and age was investigated. The incidence of anergy and relative anergy was higher in patients over 59 years than in patients under 60 years (p<0.001).     

Nitrogen sparing effects and mechanisms of branched-chain amino acids in the injured rat

A series of experiments in a rat injury model were designed to elucidate the role and mechanisms of branched-chain amino acids in the post-injury catabolism. Our results suggest that: 1. Nutritional support can maintain nitrogen equilibrium in the early post-operative state. 2. Branched chain amino acids exert a nitrogen sparing effect and thus prevent or minimise post-operative catabolism. 3. Increasing the amount of infused branched chain amino acids results in nitrogen retention. 4. A balanced amino-acid mixture containing 45 per cent branched chain amino acids seems to be optimal for nutritional support in the post-injury state.