Gut 1994; supplement 1: S77-S80

Technical aspects of enteral nutrition

M Keymling

AbstractAdvances in technical aspects of enteralfeeding such as the manufacture of tubesfrom polyurethane or silicone have helpedpromote the science of enteral nutrition.Nasoenteral tubes have few complica-tions, apart from a high unwantedextubation rate and some reluctancefrom patients because of cosmetic un-acceptability. Needle jejunostomy has lowmorbidity but can only be placed atlaparotomy. Percutaneous gastrotomy (inall its different guises) has beenestablished as a low risk procedure and isthe access route of choice for longtermenteral feeding, in particular for cancer,geriatric, and neurological patients.(Gut 1994; supplement 1: S77-S80)

The use of the enteral route of access forartificial nutrition dates back to the 16thcentury. It was not until the late 1 960s,however, with the advent of sophisticateddelivery systems and effective enteral diets thatits routine use in clinical medical practicebecame accepted. Progress continued through-out the past two decades with developmentssuch as enteral tube materials like poly-urethane and silicone suitable for longer termplacement,' and commercially produced com-plete diet formulations as effective as paren-teral formulations.2-6

Appropriate diet delivery systems arerequired for a number of reasons including:(1) inability to swallow because of disease(for example - head and neck, oesophagealtumours; neurological - multiple sclerosis,stroke); (2) palatability of commerciallyproduced enteral diets often precludes oraladministration; (3) volume of feed (sometimesup to 2-5 1/24 h) may be difficult for somepatients (for example the elderly) to consume).The different access routes to the gastro-

intestinal tract are considered in this study.

Medizinische Klinik,Kreiskrankenhaus,Bad Hersfeld,GermanyM Keymling

Correspondence to:Priv-Doz DrM Keymling,Medizinische Klinik,Kreiskrankenhaus, Seilerweg29, D 6430 Bad Hersfeld,Germany.

Nasoenteral tubesNasoenteral tube feeding is widely accepted asa very simple and safe method of diet delivery.A number of techniques have been used toensure accurate placement of the tube andmaintenance of position once placed.Manegold7 described the role of endoscopy.One particularly novel technique was thedevelopment of an enteral tube with aninflatable balloon at the distal tip. Inflation ofthe balloon theoretically permitted the gastricpressure waves and peristalsis to convey the tipof the tube through the pylorus and thenthrough the duodenum. Once placed theballoon was further inflated and broke away

from the distal tube, at which point it deflatedand continued its passage through the gastro-intestinal tract to be expelled through therectum. Another design of tube included an'olive', which sat intranasally, supposedlypreventing accidental tube extubation.Accidental tube extubation remains the com-monest complication of nasoenteral tubefeeding. Cosmetic dissatisfaction and delay inthe resolution of deglutition disorders after astroke have also been described (Table I).8 Inrare cases fatal misplacement of tubes occurs(for example into the lung, through theoesophagus, or into the brain) .9- Thedecision on the placement of the distal end ofthe nasoenteral tube is a clinical one, and itmay be placed in the stomach, duodenum orjejunum. x Ray should be used to recordcorrect positioning after insertion and toidentify other complications such as tubeknotting. 12Some additional points should be made,

which include firstly that in elderly or confusedpatients frequent tube extubation interruptstreatment and prevents nutritional goals beingmet. Secondly, in patients with disorderedswallowing the situation can be worsened bythe presence of a nasoenteral tube. Finally,placement oftubes in patients with a tumour inthe upper gastrointestinal tract or pharynx canbe difficult.

Needle jejunostomyDelany described the placement of a fine borefeeding tube with a peel away catheter into thejejunum. It is a simple procedure appropriatefor longer term feeding. The technique createsa submucosal tunnel for the catheter about 10cm in length, which minimises the risk ofdisplacement or intraperitoneal leakage of diet.Removal does not require further laparotomy.Mortality is about 2%.13 General anaesthesia isrequired, however, and with adequate alter-native techniques available the needle jejuno-stomy is probably only indicated if concurrentsurgery is taking place and the patient is, or isin danger, of becoming malnourished. Typicalpatients include those about to have extensivetumour resection or those after multipletrauma.

TABLE I Complications of nasoenteric feeding tubes

MajorOesophageal perforationOesophageal bleedingOesophageal stricturesTube misplacementPulmonary aspiration of dietMinorCosmeticDelay in resolution of deglutition disorders after strokeFrequent accidental extubationSpontaneous rugration of the tip of the tube

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Figure 1: The 'pull through' technique of inserting perctaneous endoscopic gastrostomy feeding tubes.

Percutaneous endoscopic gastrostomyIn 1980 a new technique of gastrostomy tubeinsertion was developed that was done underendoscopic control and local anaesthesia.14The simplicity and low morbidity andmortality mean that this technique is the bestmethod for access in the patient requiringlonger term enteral feeding. 15 16

TECHNIQUESThe 'pull through' technique is described. Thesupine patient is given an endoscopy and thestomach distended with air. The tip of thepalpating finger may be seen through theabdominal wall (Fig 1 a) and a cannula for localanaesthesia is inserted through the wall intothe stomach, under direct vision of theendoscopist (Fig lb). A puncture cannula ispushed from outside into the stomach (Fig 1 c)serving as a guide for the thread, which isintroduced from outside and grabbed by theendoscope forceps (Fig ld) and pulled up theoesophagus and out of the mouth. This threadis now fixed to a preformed gastrostomy tubewith a circular buffer, and the thread is pulledback through the abdominal wall pulling thegastrostomy tube until it abuts the gastricmucosa (Fig 1 e). A fixation device is thenattached to prevent movement.

Sacks and Vine17 modified the technique byreplacing the thread with a guidewire overwhich the gastrostomy tube was pushed. Theapparent slight advantages of this pull throughtechnique are probably clinically irrelevant.'8A completely different system (the direct

stab approach) was described by Russell.'9

Still under endoscopic control, the gastrotomytube is inserted externally through theabdominal wall. Unfortunately this techniquegives rise to the 'tent roof phenomenonparticularly in larger subjects. In these casesthe cannula is not long enough to penetrate thegastric mucosa externally but merely pushes itdown so that the endoscopic appearance is of a'tent roof (Fig 2).A number of different retainer systems are

used including balloons, buttons or spirals.'9 20The spiral retainer system is open to criticismon grounds of safety2l possibly because of itslength and rigidity.

Figure 2: 'Tent roof' phenomenon that can occur during thedirect stab approach of inserting gastrostomy tubesexternally through the abdominal wall.

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Technical aspects of enteral nutrition

TABLE II Contraindications to non-surgical gastrostomyfeeding tube placement

CoagulopathiesMissed diaphanoscopyPeritonitisIleusNo informed consentAnorexia nervosa

Fluoroscopic gastrostomyThe use of fluoroscopic techniques to placegastrostomy tubes has been described in recentyears and is a low morbidity procedure. For thistechnique the stomach is inflated by instillationof air (down a nasogastric tube placed forthe purpose) so that it can be localised byx ray. Endoscopy is not required, which maypermit placement in certain patients in whomendoscopy is either impossible or contra-indicated (for example some oropharyngealtumours). Reported death rates for this tech-nique are about 0-8%, with a minor compli-cation rate of about 5%. There are certaindisadvantages. The technique cannot be usedfor access to the jejunum, and if the 'tent roofphenomenon described earlier develops thenthe procedure cannot be done.Whenever possible the stomach should be

assessed before any gastrostomy tube insertionbecause an undiagnosed abnormality such aspeptic ulcer or carcinoma may coincidentallybe present.8 There are certain contraindica-tions to any non-surgical gastrostomy place-ment (Table II). The inability to auscultate orvisualise the stomach occurs in about 1% ofcases and is generally caused by peritonealcarcinomatosis or previous surgery. Fullyinformed consent of the patient or theirguardian is of course mandatory to highlightthat in many cases this procedure is palliativeand will not affect the eventual outcome of theunderlying disease. Anorexia nervosa is con-sidered an absolute contraindication to gastro-stomy placement because such patients oftenmanipulate their enteral feeding regimens.

Table III compares the different feedingtechniques described. Nasoenteral tube place-ment requires the least experience, while, ofthe interventional techniques, endoscopicgastrostomy seems to be the best procedure.

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TABLE III Summary of techniqz

Nasoenteric tubeNeedle jejunostomyFluoroscopic gastrostomyEndoscopic gastrostomy

-=No; +=Yes.

site) is most common and may be present from3 to 15% of cases,15 depending on the medicalcentre. Difference between centres are difficultto explain, but may relate to inconsistencies inthe definition of infection and differences intechniques of prophylaxis. Differences ingastrotomy technique used probably have noinfluence on subsequent infection rates.Preliminary results from our unit, investigatingthe relation between bacterial colonisation ofthe pharynx and gastrostomy puncture siteimmediately after 'pull through' of thegastrostomy show differences in bacterialpopulations. Our puncture site infection rate isonly 3% and suggests that the 'pull through'technique may be undertaken with low infec-tion rates. Our experience confirms that care-ful management and care with daily change ofdressing of the puncture site is the best way ofreducing local infection rates. If infectiondevelops it may be treated by local wound care- the need for tube removal is rare.About 10% of patients develop local pain at

the puncture site after tube insertion, whichmay be treated with simple analgesia.Occasionally this pain may cause diagnosticuncertainty if pneumoperitoneum is presentafter gastrotomy tube insertion, leading tounnecessary laparotomy after tube insertion.Major complications are rare. The overall

minor complication rate for gastrotomies isabout 9%, with a major complication rate of3% and a death rate of 0.8%.15 16 22 23 We havehad no deaths in a series of 600 tube insertions.Other procedure specific complications such asmajor haemorrhage, fistula, and necrotisingfasciitis are rare, but must be considered.24

Clinical applicationThe low morbidity and mortality of endo-scopic gastrostomy placement has allowed it tobecome a popular route of access for enteralnutrition in three key patient groups -oncology, geriatric, and neurological patients.

ONCOLOGY PATIENTSCachexia occurs in 40% of cancer

patients.25-27 The causes are as yet not fullyknown, but in many cases diet supple-

"omplications of gastrostomy mentation alone will not reverse the cachexia.'f gastrotomy is performed carefully according Increasingly enteral (and sometime parenteral):o predefined protocols technical complica- nutrition support is appropriate. The intro-ions such as early displacement (common for duction of endoscopic gastrostomy hasiasoenteral tubes) are rare. Care protocols permitted the widespread use of ambulatorynonitored by nutrition support teams enteral feeding in this group - a developmentninimise complications such as tube blockage welcomed by both clinicians and patients.mom coagulated diet. In our patients with unresectable cancer,Clinically minor complications occur quite two main indications for the introduction of

ften, and local infection (around the stoma enteral feeding are apparent. Firstly, those withweight loss (>5 kg in four weeks), and

ues offeeding tube placement secondly those with intestinal malignantGeneral structure giving rise to intermittent subacute

x Ray Laparotomy Endoscopy Anaesthesia obstruction, which is aggravated by the+ + + ingestion of solid food. For these patients

- - -+ continual infusion of liquid enteral diet can be+ - + of benefit in reducing symptoms.

Tube feeding is a well proved way oftreating weight loss in patients with advanced

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S80 Keymling

cancer.28 29 Our patients show a mean weightgain of 2 9 kg (range -2 8 to + 13 kg). Despitethis encouraging weight gain, metabolicparameters seem unchanged.

For those with proximal malignant stricturesthe distal end of the enteral tube should beplaced (when possible) distal to the stricture.This may require endoscopic or fluoroscopicmanipulation. In some cases dilation of thestricture might be appropriate. In recent yearsthe use of intestinal self expanding mesh graftstents have been advocated. Gastrostomy orjejunostomy can then be performed. Recentlywe described the introduction of a self expand-ing stent through a gastrostomy tube to beplaced in a malignant duodenal stricture. Afine bore feeding tube was then passed throughthe gastrostomy and stent into the distal non-obstructed part of the duodenum. Thiscombination treatment permitted the patientto orally ingest a soft diet supplemented bytube feeding.30The time spent in hospital after endoscopic

gastrostomy feeding tube placement is short,and in our unit tube placement in somepatients is carried out as a day case. The mainbenefit of gastrostomy feeding in cancerpatients is a better quality of life,3' as a result ofreversal of weight loss and respite fromabdominal pain. The added bonus is that thepatient may be treated at home.

GERIATRIC AND NEUROLOGICAL PATIENTSStrokes are common in subjects over 60.32As the mean survival of Western societiesincreases, larger numbers of patients presentwith nutrition problems associated withdeglutition disorders after stroke. Many of theneurological deficits after stroke will recover,but may take many weeks or months, duringwhich time nutritional state needs to bemaintained to avert the development ofcomplications such as bedsores. Thus a simpleand effective means of delivering nutritionmay be required. Nasoenteral tubes mayadversely affect recovery of swallowingfunction,33 and thus gastrostomy feeding isthe best technique for this patient group. Inour own stroke patients 20% will return tonormal swallowing after an average of threemonths.1 Orr G, Wade J, Bothe A, Blackburn GL. Alternatives to

total parenteral nutrition in the critically ill patient. CritCare Med 1980; 8: 29-34.

2 Allardyce DB, Groves AC. A comparison of nutritionalgains resulting from intravenous and enteral feeding. SurgGynecol Obstet, 1984; 139: 179-84.

3 Yeung CK, Smith RC, Hill GL. Effect of an elemental dieton body composition. Gastroenterology 1979; 77: 652-7.

4 Heymsfield SB, Bethel RA, Ansley JD, Nixon DW, RudmanD. Enteral hyperalimentation: an alternative to centralvenous hyperalimentation. Ann Intern Med 1979; 90:63-71.

5 Chrysomilides SA, Kaminsky MV. Home enteral andparenteral nutritional support: a comparison. Am J ClinNutr 1981; 34: 2271-5.

6 Doip R, Grunert A, Bohm A. Enterale oder parenteraleErnahrungstherapie Eine vergleichende klinische Studie.Infusionstherapie 1983; 10: 286-90.

7 Manegold BC, Mechtersheimer U, Jung M.Applikationsformen zur enteralen Sondenernahrung. einUberblick. medwelt 1989; 38: 26-8.

8 Yeung EY, Ho CS. Percutaneous radiologic gastrostomy.Clin Gastroenterol 1992; 6: 297-317.

9 Frenstad JD, Martin SH. Lethal complication frominsertion of nasogastric tube after severe basilar skullfracture. J Trauma 1978; 18: 820-2.

10 Ghahremani GG, Gould RJ. Nasoenteric feeding tubes:radiographic detection of complications. Dig Dis Sci 1986;31: 574-85.

11 James RH. An unusual complication of passing a narrowbore nasogastric tube. Anesthesia 1978; 33: 76.

12 Rabast U. Lokalisation von Ernahrungssonden. Dtsch MedWochenschr 1985; 110: 1074-6.

13 Page CP. Needle catheter jejunostomy. ContemporarySurgery 1981; 19: 29-47.

14 Gauderer WL, Ponsky JL, Izant RJ. Gastrostomy withoutlaparotomy: a percutaneous endoscopic technique. JPediatri Surg 1980; 15: 872-5.

15 Larson DE, Burton DD, Schroeder KW, DiMagno EP.Percutaneous endoscopic gastrostomy. Indications,success, complications and mortality in 314 consecutivecases. Gastroenterology 1987; 93: 48-52.

16 Ponsky JL, Gauderer MWL, Stellato TA, Aszodi A.Percutaneous approaches to enteral alimentation. Am JSurg 1985; 149: 102-5.

17 Sacks BA, Vine HS, Plestrant AM, Ellison HP, ShropshireD, Lowe R. A nonoperative technique for establishmentof a gastrostomy in the dog. Invest Radio 1983; 18:485-7.

18 Hogan RB, DeMarco DC, Hamilton JK, Walker CO, PolterDE. Percutaneous endoscopic gastrostomy - to push orpull. Gastrointest Endosc 1986; 32: 253-8.

19 Russell TR, Brotman M. Norris F. Percutaneousgastrostomy. Am 7 Surg 1984; 148: 132-7.

20 Vestweber KH, Troidl H, Sommer H. PerkutaneEndoskopische Gastrostomie. Dtsch Med Wochenschr1984; 109: 1203-4.

21 Fruehmorgen P, Hardegg G, Heller T. Sondendislokationnach perkutaner, endoskopisch kontrollierterGastrostomie Ein Fallbericht. Z Gastroenterol 1991; 29:655-8.

22 Foutch PG, Woods CA, Talbert GA, Sanowski RA. Acritical analysis of the Sacks-Vine gastrostomy tube: areview of 120 consecutive procedures. Am J Gastroenterol1988; 83: 812-5.

23 Miller RE, Castelmain B, Lacqua FJ, Kotler DP.Percutaneous endoscopic gastrostomy: results in 316patients and review of literature. Surg Endos 1989; 3:186-90.

24 Greif JM, Ragland JJ, Oschsner MG. Fatal necrotizingfasciitis complicating percutaneous endoscopicgastrostomy. Gastrointest Endosc 1986; 32: 292-4.

25 Lundvick J. Nutritional screening of the oncological patient.Nutritional Support Services 1983; 3: 21-3.

26 Theologides A. Cancer cachexia. Cancer 1979; 43: 2065-9.27 DeWys WD. Anorexia as a general effect of cancer. Cancer

1979; 43: 2013-9.28 Luibke HJ, Weithofer G, Keymling M, Bloch R. Supportive

Emrnhrungstherapie bei Patienten mit metastasierendenTumoren des Gastrointestinaltraktes. Tumor DiagnostikTherapie 1982; 3: 259-68.

29 Keymling M. Die perkutane endoskopisch kontrollierteGastrostomie in der internistischen Onkologie. Medwelt1987; 38: 37-9.

30 Keymling M, Knyrim K, Wagner J, Vakil M. Percutaneousstent implantation in malignant duodenal obstruction.Gastrointest Endosc 1993; 39: 439-41.

31 Schmitz JM, Seiter A, Czischke C, Grunert A, AhnefeldFW. M6glichkeiten und Grenzen der parenteralenErnihrung bei onkologischen Patienten. AktueUeOnkologie 1986; 35: 209-22.

32 Lindner 0. Differential-Therapie bei der Multimorbiditatin der Geriatrie. Acta Gerontologica 1974; 4: 115-22.

33 Selley WG. Swallowing difficulties in stroke patients: a newtreatment. Age ageing 1985; 14: 361-5.

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