**4. Enteral nutrition**

Enteral route is physiologic and *'A functioning gastrointestinal system should be used to prevent its malfunction'*. Oral nutritional is ideal. Patients with dysphagia are at risk of aspiration pneumonia. Authors recommend a swallowing history and assessment prior to oral feeding. Until safety of oral feeding is established, tube feeding should be considered. Figure 3 outlines a simplistic approach in decision making for nutritional supplementation.

### **4.1. Formula feeds**

There are various feeding formulas and selection should be based on fluid electrolyte and metabolic needs, digestion and absorption capacity, caloric and protein density of formula, physical characteristics of formula (osmolality, viscosity etc.), and cost. General purpose feeding formulas contain intact proteins and need an intact digestive and absorptive function of gastrointestinal system. Semi-elemental feeds contain free amino acids with minimal fat and are used in patients with compromised gastrointestinal function. There are also various disease-specific feeds available for patients with hepatic, renal, or pulmonary dysfunction. In addition, nutrient composition of the formulas can be altered to tailor individual patients need and such modular feeds require mixing by local pharmacy and are costly [31]. Once the feeding formula is decided and the nutritional requirement calculated, the rate and delivery of the feeding is established.

**Figure 3.** Algorithm of nutritional supplementation

#### **4.2. Feed delivery**

pneumonia. Authors recommend a swallowing history and assessment prior to oral feeding. Until safety of oral feeding is established, tube feeding should be considered. Figure 3 outlines

There are various feeding formulas and selection should be based on fluid electrolyte and metabolic needs, digestion and absorption capacity, caloric and protein density of formula, physical characteristics of formula (osmolality, viscosity etc.), and cost. General purpose feeding formulas contain intact proteins and need an intact digestive and absorptive function of gastrointestinal system. Semi-elemental feeds contain free amino acids with minimal fat and are used in patients with compromised gastrointestinal function. There are also various disease-specific feeds available for patients with hepatic, renal, or pulmonary dysfunction. In addition, nutrient composition of the formulas can be altered to tailor individual patients need and such modular feeds require mixing by local pharmacy and are costly [31]. Once the feeding formula is decided and the nutritional requirement calculated, the rate and delivery of the

a simplistic approach in decision making for nutritional supplementation.

**4.1. Formula feeds**

126 Seminars in Dysphagia

feeding is established.

**Figure 3.** Algorithm of nutritional supplementation

Intermittent bolus feeding is convenient to administer by nasogastric or percutaneous gastric tube and is suitable in ambulatory patients. Although there are no definitive studies, bolus feeding reduces lower esophageal sphincter pressure and may increase the chance for reflux and aspiration [32]. Intermittent cyclic feeding is indicated during weaning from tube feeding to oral feeding. It can be pump-assisted or gravity-assisted and feeding cycles of varying duration of period can be planned. This feeding is advantageous when an overnight tube feed is administered and the patient continues his normal oral intake during the day. Constant feeding infusion assisted by pump or gravity is indicated in bedridden patients with critical illness. Nasal tubes are associated with discomfort, excoriation and bleeding, and anosmia. Hence, when long-term feeding is required, percutaneous gastrostomy or jejunostomy tubes should be used. In a United Kingdom study involving 1,327 patients including 1,027 patients with gastrostomy tube insertion, Kurien M et al. has demonstrated that patients who undergo gastrostomy have significantly lower mortality than those who defer the procedure (11.2% vs. 35.5% at 30 days and 41.1% vs.74.3% at 1 year, p<0.0001) [33]. The most common indication of feeding gastrostomy remains inadequate swallowing as a result of a neurological event, oropharyngeal or esophageal cancer, or facial trauma [34]. Traditionally, tube feeding is delayed until the next day after the procedure. Authors' personal preference is to institute the feeding at the next opportunity. In a meta-analysis of six randomised controlled trials involv‐ ing 467 patients, Bechtold ML et al. has shown that early feeding (defined as within 4 hrs) after percutaneous endoscopic gastrostomy placement was safe [35]. In patients with restricted mouth opening, oral cavity is inaccessible and a surgical gastrostomy needs to be created. Feeding gastrostomy is associated with the risk of aspiration and is not possible in patients with gastric outlet obstruction, gastroparesis, or gastric resection. In such patients, feeding jejunostomy is an alternative. Percutaneous feeding jejunostomy can also be inserted via the existing gastrostomy site. Percutaneous placement of feeding jejunostomy is technically difficult compared to gastrostomy. In a study involving 150 patients without a previous history of major abdominal surgery, Shike M et al. found that direct percutaneous endoscopic jejunostomy was successful in 129 procedures (86%) and aspiration occurred in 3% of patients [36]. Enteral nutrition preserves the gut integrity, reduces bacterial translocation, maintains the gut immune function, is easily administered and monitored, and cheaper compared to parenteral nutrition. However, it can also lead to complications.

#### **4.3. Enteral nutrition: Common issues**

Enteral nutrition causes mechanical problems with tube placement (migration, clogging etc.), metabolic problems (osmotic diarrhoea, overhydration, etc.), and is labour intensive (tube management, infusion pump device usage, etc.). In patients with tube feeding, prior to commencing feeding, a radiological confirmation of tube placement must be checked. Tube clogging could be prevented by using a wide tube, flushing the tube with water after medicine administration, minimising gastric aspirates to keep pH levels low, and using pancreatic enzymes mixed with bicarbonate [37]. Peristomal wound infections and leakage are also common problems associated with tube feeding and add to patient and family anxiety along

with the nursing care burden [38]. In a Cochrane review with a pooled analysis of 1,271 patients from 12 randomised controlled trials, Lipp A et al. have shown that administration of pro‐ phylactic systemic antibiotics for percutaneous endoscopic gastrostomy tube placement reduces peristomal infection rates (OR 0.36, 95% CI: 0.26–0.50) [39]. Peristomal leakage can be reduced by appropriate fixation technique and antisecretory agents. In patients with persistent leakage, the tube should be withdrawn and replaced after few days or a new tube placed at the separate site, but no attempt should be made to control the leakage with a wider tube as it may exacerbate the leakage [40–42]. Diarrhoea remains the commonest gastrointestinal side effect of enteral tube feeding [43, 44]. Addition of fibre and probiotics has shown to reduce diarrhoea in enteral feeding. In a systematic review and meta-analysis including 51 studies, 43 randomised control trials and 1,762 subjects (1,591 patients and 171 healthy volunteers), Elia M et al. have shown that fibre supplementation was generally well tolerated and the incidence of diarrhoea reduced (OR 0.68, 95% CI: 0.48–0.96; 13 randomised control trials) [45]. In a randomised double blind placebo controlled trial involving 62 patients, Heimburger DC et al. have shown that most cases of diarrhoea in tube fed patients are caused by factors extraneous to tube feeding and lactobacillus treatment did not alter the risk of diarrhoea [46]. Patients on enteral feeding are also at risk of aspiration pneumonia. There are various strategies recommended to reduce the risk of aspiration namely head end of bed elevation, gastric residual volume measurement and postpyloric feeding. In a prospective randomized study involving 38 patients in medical and surgical intensive care units, endoscopically placed feeding jejunal tube-fed patients had a lower rate of pneumonia (nil vs. 10.5%) compared to patients fed by continuous gastric tube feeding [47]. In a literature review of 45 studies including patients with neurogenic oropharyngeal dysphagia over a period of 1978 to 1989, authors were not able to derive any meaningful conclusions with regard to superiority of postpyloric feeding due to limitations of individual studies with small sample size, inconsis‐ tent definitions of aspiration, varying feeding protocols, unspecified time frames, and heter‐ ogeneous populations [48]. Monitoring enteral nutrition involves fluid electrolyte balance, weight chart, serum electrolyte and glucose measurement, and stool charting. Refeeding syndrome is characterised by electrolyte depletion, fluid shifts, and glucose derangements that occur on reinstitution of nutrition in malnourished patients [49]. Chronically malnourished patients (e.g., patients with dysphagia) are at high risk of refeeding syndrome. In a study involving 321 patients with 92 patients at risk of refeeding hypophosphataemia, Zeki S et al. has shown that refeeding hypophosphataemia is more common in enteral-fed patients compared to parenteral nutrition [50]. Gradual introduction and progression of feeding over a few days with close monitoring of fluid and electrolytes can help in the prevention and early recognition of refeeding syndrome.

National Institute of Clinical Excellence (NICE) guidelines recommend that in an acute setting, if patients are unable to swallow safely or meet caloric needs orally, they should have an initial 2–4 week trial of nasogastric enteral tube feeding. Health care professionals with relevant skills and training in the diagnosis, assessment, and management of swallowing disorders should assess the prognosis and options for future nutrition support [19]. Before modifying nutritional support in a patient with dysphagia, level of alertness, need for feeding assistance, mobility, recurrent chest infections, metabolic needs, etc. should be considered [19].
