Intermittent and Bolus Methods of Feeding in Critical Care

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1 Intermittent and Bolus Methods of Feeding in Critical Care Satomi Ichimaru a * and Teruyoshi Amagai b a Department of Nutrition Management, Kobe City Medical Center General Hospital, Kobe, Hyogo, Japan b Department of Food Science and Nutrition, School of Human Environmental Sciences, Mukogawa Women s University, Nishinomiya, Japan Abstract Enteral nutrition (EN) can be administered using various methods such as continuous, cyclic, intermittent, and bolus techniques, either alone or in combination. In continuous feeding, an hourly rate of EN is administered using a feeding pump over 24 h. In cyclic feeding, EN is administered via a feeding pump in less than a 24-h time period. In intermittent feeding, EN is administered over min every 4-6 h with or without a feeding pump. In bolus feeding, EN is administered via a syringe or gravity drip over a 4-10-min period. A number of factors are taken into consideration when selecting EN delivery modalities, such as the medical condition of the patient, expected tolerance to tube feeding, location of the feeding tube tip, type of formula used, nutritional requirements, mobility of the patient, availability of electric feeding pump, and cost. However, too little data are available at present to make a strong recommendation for one particular method of enteral feeding over others. In practice, it is generally considered acceptable for pump-assisted continuous feeding in critically ill patients to be initiated at a rate of ml/h and then gradually increased to the target rate. For medically stable patients, intermittent and bolus feeding methods are preferred due to practical issues, such as patient mobility, convenience, and cost. At present, no evidence is available regarding the optimum feeding modality for not only an ordinary clinical setting but also critical care setting. Abbreviations EN GI ICU NG RCT VAP Enteral nutrition Gastrointestinal Intensive care unit Nasogastric Randomized controlled trials Ventilator-associated pneumonia Introduction Enteral nutrition (EN) can be administered via various modalities, including continuous, cyclic, intermittent, and bolus techniques, either alone or in combination. A number of factors must be taken into consideration when selecting a EN delivery method, such as the medical condition of the patient, expected tolerance to tube feeding, location of the feeding tube tip (e.g., gastric or jejunal), * satomi.ichimaru@gmail.com Page 1 of 17

2 Continuous Cyclic Intermittent EN over min every 4-6 h with/without feeding pump Bolus EN via feeding pump for 24 h/day EN via feeding pump for <24 h/day EN over short time period at specified interval via gravity drip or syringe EN, enternal nutrition Feeding time Break time Fig. 1 Methods of enteral tube feeding type of formula used, nutritional requirement, mobility of patient, availability of feeding pump, and cost. However, too few data are available at present to support a strong recommendation for the best starting method for the initiation of EN in critically ill patients to improve patient outcomes. This chapter provides an overview of several methods for delivering EN, including their advantages and disadvantages as well as indications in critical care. Methods of Administration Four modalities have been developed for enteral tube feeding (Fig. 1). Continuous Feeding Continuous feeding, defined as an hourly rate of EN administration using an electric enteral feeding pump, is the preferred method for feeding patients who are critically ill, being incubated for respiratory failure, exhibiting poor glycemic control, being fed via a jejunostomy tube, or intolerant of intermittent feedings (Brantley and Mills 2012). The typical recommendation for continuous feeding is to start at ml/h, advancing by ml every 4-24 h (Parrish 2003). However, while continuous feeding is used in most critical care units, only a few relatively outdated studies have provided evidence to support this practice. In a study of 76 adult burn patients, those receiving continuous tube feeding had lower stool frequency and less time required to reach nutritional goals than those receiving bolus feeding (Hiebert et al. 1981). In neurologically impaired adult patients, aspiration was observed less frequently in those receiving continuous feeding (1/17) than in those receiving intermittent feeding (3/17) (Kocan and Hickisch 1986). Regarding drug-nutrient interactions, continuous feeding is the most problematic method and frequently requires interruption of tube feeding for the administration of medication. The rate of tube feeding might therefore have to be increased to provide appropriate nutrition during the reduced infusion period. Cyclic Feeding Cyclic feeding provides EN using an electric enteral feeding pump in less than a 24-h time period. Similar to continuous administration, this delivery method may be used when the feeding tube is located at the stomach or small intestine. Depending on patient tolerance to volume load, infusion time might be decreased from 24 h per day to as short as 8 h. As the patient recovers from illness, this Page 2 of 17

3 Table 1 Advantages, disadvantages, and indications of each feeding method Feeding method Advantage Disadvantage Indication Continuous May improve tolerance May reduce risk of aspiration Increased time for nutrient absorption Cyclic Facilitates transition of support to oral diet Allows daytime ambulation Encourages patient to eat normal meals and snacks Intermittent Feeding pump may not be required May enhance quality of life Allows greater mobility between feedings More physiological May be better tolerated than bolus feeding Bolus More physiological Feeding pump not required Inexpensive and easy administration Limits feeding time Patient is free to move about, participate in rehabilitation therapies, and live a relatively normal life More likely patient will receive all of formula Feeding pump required May restrict ambulation More expensive Feeding pump required May require high infusion rates May promote intolerance Increased risk for aspiration Gastric distention Delayed gastric emptying Increased risk of aspiration Hypertonic, high-fat, or high-fiber formulas may delay gastric emptying or result in osmotic diarrhea Initiation of feeding in critically ill patients Promote tolerance Compromised gastric function Feeding into small bowel Intolerance to other feeding methods Transitioning from EN to oral nutrition (enhance appetite during the day) Supplement inadequate oral intake Free patient from enteral feedings during the day Intolerance to bolus administration Initiation of EN without feeding pump Recommended for gastric feeding Normal gastric function method may be used to transition from the 24-h continuous feeding method to 12-h nocturnal feeding in an effort to enhance the patient s appetite during the day and increase mobility by freeing the patient from tubing and pump connections (Brantley and Mills 2012). Intermittent Feeding Intermittent feeding is administered via an electric enteral feeding pump or gravity drip. Volume can range from 240 to 720 ml, be administered over a time period ranging from 20 to 60 min, and be provided anywhere from 4 to 6 times per day depending on the volume of formula required to meet the patient s specific needs (Brantley and Mills 2012). However, while this feeding method is more physiological and affords greater patient mobility between feedings, it is not without its disadvantages, such as risk of aspiration (Kocan and Hickisch 1986), diarrhea (Ciocon et al. 1992), and gastric distention. Some alert and mobile patients may increase the volume of each feeding as tolerated and decrease the number of feedings required per day to improve quality of life (Brantley and Mills 2012). Page 3 of 17

4 Table 2 RCTs comparing cyclic and continuous feeding Author and year Campbell et al. (1990) Bonten et al. (1996)) Patient number Patient characteristic Cyclic feeding 18 patients n ¼ 9 n ¼ 9 Route: NG 60 patients n ¼ 30 n ¼ 30 Route: NG Patients who underwent major surgery for malignant disease of the buccopharynx and larynx Mechanically ventilated patients admitted to mixed or cardiosurgical lcu Fed only at night (i.e., 5 pm 9 am) Continuous feeding Follow-up 24 h/day 5 days Oxygen consumption Outcome measure Result Significantly lower in cyclic patients over days 2-5 (P ¼ 0.021) Cumulative g nitrogen g balance (P < 0.05) Biochemical Higher serum glucose and insulin in cyclic group on day 5 (P < 0.01; Urinary catecholamines P < 0.05, respectively) Epinephrine and dopamine excretions were higher in the continuous group on days 3 5 (P < 0.05, P < 0.01, respectively) 18 h/day 24 h/day 14 days Intragastric ph decreased from 3.5 to 2.2 when feeding was discontinued Acquired colonization with EGB in the oropharynx Acquired colonization with EGB in the trachea GRV >400 ml/day Incidence of VAP during and after study (P ¼ ) 63.3 % 66.7 % (NS) 46.7 % 63.3 % (NS) 16.7 % 6.7 % (No P-values given) 16.7 % 16.7 % (NS) ICU mortality 6.7 % 13.3 % (P ¼ 0.4) Page 4 of 17

5 Van Berge Henegouwen et al. (1997) Tamowicz et al. (2007) 57 patients n ¼ 27 n ¼ 30 Route: jejunostomy 40 patients n ¼ 20 n ¼ 20 Patients with pancreatic or periampullary malignancies undergoing pylorus-preserving pancreatoduodenectomy Mechanically ventilated patients (aged years) with an anticipated ventilation period for a minimum of 6 days 18 h/day (6 am midnight) 18 h/d with a night break 24 h/day Until patients could fulfill their caloric needs orally Delayed gastric emptying Nasogastric intubation, days, median (range) Jejunal catheter feeding, days, median (range) First day of normal diet, days, median (range) Hospital stay, days, median (range) Small bowel transit time, min, median (range) 24 h/day 6 days ph of gastric content 26 % 23 % (P ¼ 0.82) 4 (1 25) 5.5 (1 65) (P ¼ 0.82) 8 (0 27) 9 (1 28) (P ¼ 0.60) 9 (5 38) 11 (5 68) (P ¼ 0.04) 14 (10 46) 17 (9 73) (P ¼ 0.04) 130 (60 180) 110 (70 150) (P ¼ 0.15) significantly lower during the night break (P < 0.01) no significant changes during the night Bacteriological higher increase in analysis of no. of species and genera of gastric content microorganisms isolated and frequency of isolation on day 6 VAP 20 % 35 % (NS) EGB enteral gram-negative bacteria, EN enteral nutrition, GRV gastric residual volume, ICU intensive care unit, NG nasogastric, NS not significant, RCT randomized clinical trial, VAP ventilator-associated pneumonia Page 5 of 17

6 Table 3 RCTs comparing intermittent and continuous feeding Author and year Kocan and Hickisch (1986) Ciocon et al. (1992) Patient number 34 patients n ¼ 17 n ¼ 17 Route ¼ NG 60 patients n ¼ 30 n ¼ 30 Route ¼ NG Patient characteristic Intermittent feeding Continuous feeding Follow-up Outcome measure Result Neurosurgical ICU adults Elderly patients prescribed NG tube feedings because of difficulty in swallowing and inadequate intake 1 h every 4 h Maximum rate 370 ml/h 200 to 400 ml of feeding over 30 min by force of gravity every 4 h 24 h/day Maximum rate 120 ml/h 10 days Mean number of stools/ day (NS) Aspiration 18 % 6 % (NS) Mean number of days taken to reach 5.20 days nutritional target 4.18 days (NS) Mean weight loss over study period 1.68 kg 1.21 kg (NS) 24 h/day 7 days Diarrhea 96.7 % 66.7 % (P ¼ 0.008) > 4 days or longer diarrhea 60 % 23 % (P ¼ 0.008) Aspiration 33.3 % 16.7 % (NS) Clogged tube 16.7 % 50.0 % (P ¼ 0.01) Agitation, selfextubation Discrepancy between recommended and actually provided No significant difference between the groups kcal/day Page 6 of 17

7 Beau and Labat (1994) 12 patients n ¼ 6 n ¼ 6 Route: NG Patients with severe swallowing disorders related to chronic neurological diseases and a need for exclusive and prolonged EN Three 500-ml boluses infused for 1 to 2 h each at 9 am, 1 pm, and 6 pm, delivered by a gravity drip 23 h/day from 10 am to 9 am, on an ambulatory basis, using a portable system that allowed free physical activity during daytime calories in the 7-day period Time to administer and monitor feeding process kcal/day (P ¼ 0.1) min/ day min/ day (P ¼ 0.25) 7 days Biochemical Reduction during study period TC: % (P < 0.001) LDL-C: % (P < 0.001) Insulin/glucagon: % (P < 0.05) TC: % LDL-C: % Insulin/glucagon: % (NS) (continued) Page 7 of 17

8 Table 3 (continued) Author and year Serpa et al. (2003) Patient number 28 patients n ¼ 14 n ¼ 14 Route: NG Macleod et al. (2007) 164 patients n ¼ 79 n ¼ 81 Route: NG/OG Patient characteristic Intermittent feeding Continuous feeding Follow-up Outcome measure Result Seriously ill adults who were unable to ingest an oral diet but who had conserved GI function Patients admitted to the trauma intensive care unit who were ordered to start EN 8 aliquots administered over a 1-h period, each at 3-h intervals (1-h infusion period followed by 2-h standby period) Initial feeding of 100 ml every 4 h was repeated twice and increased by 100 ml every 8 h to the target volume (24-h target/6). Each feeding was delivered via a feeding pump in min 24 h/day 3 days Complications: high GRV, aspiration, abdominal distension, nausea, vomiting, diarrhea, tube obstruction, and tube 24 h/day Volume started at 20 ml/h for 8 h and increased by 20 ml/h increments every 8 h to reach the target volume displacement No significant difference between the groups in all complications Total daily input Day 1: ml ml (P < 0.05) No significant difference on day 2or3 7 days % total calories for days % 58.3 % (NS) Intermittent patients reached target faster Intermittent patients had a higher probability of being on target (P ¼ 0.01) Page 8 of 17

9 No. of days patients maintained target level of EN 4 days per patient (95 % CI ) 3 days per patient (95 % CI ). Diarrhea 6.3 % 3.7 % (P ¼ 0.45) Pneumonia 48 % 41 % (P ¼ 0.45) ICU stay days days (P ¼ 0.69) ICU mortality 13.9 % 7.4 % (P ¼ 0.18) EN enteral nutrition, GI gastrointestinal, GRV gastric residual volume, ICU intensive care unit, LDL low-density lipoprotein cholesterol, NG nasogastric, NS not significant, OG oralgastric, RCT randomized clinical trial, TC total cholesterol Page 9 of 17

10 Table 4 RCTs comparing bolus feeding and continuous feeding Author and year Pichard and Roulet (1984) Patient number Patient characteristic Bolus feeding Continuous feeding 31 patients Bolus: n ¼ 15 n ¼ 16 Route: NG Patients with operable buccopharyngeal cancer and for whom at least 10 days of NG tube feeding had been planned 1,250 ml/day was given in 4 or 5 x 5- to 10-min meals and increased to 1,750 or 2,000 ml 20 ml/h administered until the following morning. During the following 24 h, 2/3 of the daily volume were instilled, and over the 24-h period, the entire volume Followup Outcome measure Result 20 days Changes in weight and AMC during the first 20 postoperative days Biochemical Change in Alb during the first 20 postoperative days Changes in TF and TTR during the first 14 postoperative days Weight Bolus: kg (P < 0.01) kg (p < 0.01) AMC Bolus: decreased cm (NS) increased cm (P < 0.01) Alb Bolus: g/l (P < 0.001) g/l (NS) TF Bolus: mg/100 ml (P < 0.001) mg/100 ml (P < 0.01) TTR Bolus: mg/100 ml (NS) mg/100 ml (P < 0.01) Page 10 of 17

11 Campbell et al. (1983) Steevens et al. (2002) 10 patients Bolus: n ¼ 5 n ¼ 5 Route: NG 18 patients Bolus: n ¼ 9 n ¼ 9 Route: NG Male patients undergoing major surgery for squamous cell carcinoma of the buccopharynx and larynx Multiple-trauma patients (including head injury) with Injury Severity Score 20 2 h in 9 equally divided quantities between 6am 10 pm Started with bolus of 125 ml by force of gravity over 15 min every 4 h and increased every 12 h by 125 ml increments until target volume was attained 24 h/day 5 days Oxygen consumption Initiated at 25 ml/h and advanced every 12 h by 25 ml/h until target rate was achieved Lower in bolus group than in continuous group on days 4 5 (P < 0.01) Cumulative Bolus: nitrogen balance (P < 0.05) Biochemical Postoperative AAT was significantly higher in continuous group than in bolus group on days 3, 4, and 5, ggt on day 5, and ALP on days 2 and 5 7 days Interruption in EN delivery due to elevated GRV % of target delivered cumulatively for 7 days Bolus: 55 % 33 % (No P-values given) Bolus: 86.8 % 87 % (No P-values given) Diarrhea Bolus: 55 % (for 14/65 days) 22 % (for 6/49 days) (No P-values given) Aspiration Bolus: 11.1 % 0 % (No P-values given) TTR, urine urea No significant difference nitrogen between groups AAT alanine aminotransferase, Alb albumin, ALP alkaline phosphatase, AMC arm muscle circumference, GRV gastric residual volume, NG nasogastric, NS not significant, RCT randomized clinical trial, TF transferrin, TTR transthyretin; ggt g-glutamyl transpeptidase Page 11 of 17

12 Bolus Feeding Bolus feeding is defined as formula administered via a syringe or gravity drip over a short period of time. A typical feeding regimen might provide 240 ml of formula over a 4-10-min period infused 3 6 times per day (Brantley and Mills 2012). This rapid delivery method is used for clinically stable patients with normal gastric function and is generally not well tolerated in patients with small bowel access. Further, rapid infusion can cause GI intolerance and discomfort (Brantley and Mills 2012). Bolus feeding offers the advantage of allowing administration of medication to be separated from feeding. In addition, this method closely mimics ordinary eating patterns and can reduce feeding time, thereby enabling the patient to move about freely, participate in rehabilitation therapy, and live a more normal life. The advantages, disadvantages, and indications of each feeding method are shown in Table 1. Studies on Enteral Feeding Methods Results of randomized controlled trials (RCTs) comparing the four enteral feeding methods are summarized in Tables 2 5. Cyclic versus Continuous Feeding Four studies compared 16- to 18-h cyclic feeding versus 24-h continuous feeding (Table 2). These studies were conducted in critically ill, mechanically ventilated patients and postsurgical patients. Bonten et al. (1996) and Tamowicz et al. (2007) postulated that cyclic feeding had a beneficial effect on gastric acidity and bacterial colonization of the stomach and respiratory tract, helping to prevent ventilator-associated pneumonia (VAP). In both studies, gastric ph significantly decreased when feeding was discontinued in cyclic feeding groups. However, the rate of gastric colonization was only reduced in the study by Tamowicz et al., with the incidence of VAP being relatively similar between cyclic and continuous feeding groups in both studies. No significant differences were noted between cyclic and continuous feeding groups with regard to mortality in an intensive care unit (ICU; Bonten et al. 1996). However, another study found that the length of hospital stay was significantly shorter in patients receiving cyclic feeding than in those on continuous feeding (van Berge Henegouwen et al. 1997). Cumulative nitrogen balance for 5 days was improved in continuous feeding groups compared to cyclic feeding groups (Campbell et al. 1990). Intermittent versus Continuous Feeding Five studies compared intermittent feeding versus 24-h continuous feeding (Table 3). These studies were conducted in older patients, neurological dysphagic patients, and critically ill patients. Although regimens of intermittent feeding differed between studies, generally, a volume of ml was administered over a period of min, 3-8 times per day. In critically ill trauma patients, no significant differences were noted in either mortality in the ICU or incidence of pneumonia between intermittent and continuous feeding groups (Macleod et al. 2007). In one study, however, a significantly higher incidence of diarrhea (P ¼ 0.008) and less clogging of the nasogastric (NG) tube (P ¼ 0.01) was observed in the intermittent feeding group than in the continuous feeding group (Ciocon et al. 1992). Page 12 of 17

13 Table 5 RCTs comparing intermittent and cyclic feeding Author and year Lee and Auyeung (2003) Lee et al. (2010) Patient number 105 patients n ¼ 52 n ¼ patients n ¼ 93 n ¼ 85 Route ¼ NG Patient characteristic Patients >60 years of age receiving intermittent feeding and suffering from diarrhea Patients 60 years or older likely to require NG tube feeding for at least 4 weeks in convalescence and infirmary hospitals Intermittent feeding 10 ml/min, 250 ml/bolus, 4 6 bolus/day depending on prescribed caloric intake ml/h, 4 5 times per day NG nasogastric, NS not significant, RCT randomized clinical trial Cyclic feeding 1 2 ml/min for 16 h/day 80 ml/h, for at least 16 h/ day Follow-up Outcome measure Result 3 days Diarrhea Baseline (extended scores, to 5 in median 10 (3 40) some (range) cases) 12 (4 33) (P ¼ 0.175) Day 3 6(0 27) n ¼ 37 4(0 29) n ¼ 37 (P ¼ 0.230) Day 5 4(0 23) n ¼ 20 5(0 19) n ¼ 28 (P ¼ 0.833) 4 weeks Pneumonia 15.1 % 14.1 % (NS) Death within 4 weeks 14.0 % 8.2 % (P ¼ 0.226) Bolus versus Continuous Feeding Three studies compared bolus versus 24-h continuous feeding (Table 4). These studies were conducted in postoperative cancer patients and multiple-trauma patients. Although regimens of bolus feeding differed between these studies, generally, a volume of ml was administered over a period of 5 15 min, 5 9 times per day. Until now, little study has evaluated the outcomes of mortality or length of hospital stay between patients receiving bolus and continuous feedings. Although aspiration and diarrhea were observed more frequently in the bolus feeding group in a previous study, statistical analysis was not conducted (Steevens et al. 2002). In addition, while one study reported an improved nitrogen balance in the bolus feeding group (Campbell et al. 1983), another reported significantly improved body weight and arm circumference in the continuous feeding group instead (Pichard and Roulet 1984). Page 13 of 17

14 Intermittent versus Cyclic Feeding Two studies comparing intermittent versus 16-h continuous feeding in elderly patients (Table 5) noted no significant differences between the groups in either mortality, incidence of diarrhea, or pneumonia (Lee and Auyeung 2003; Lee et al. 2010). Application to Critical or Intensive Care Of the four feeding methods, no evidence suggests one to be superior to the others. No differences were reported in mortality or rate of infection among patients receiving EN via the four methods of administration (Bonten et al. 1996; Steevens et al. 2002; MacLeod et al. 2007; Tamowicz et al. 2007; Lee et al. 2010). Only one study reported a decreased length of hospital stay in the cyclic feeding group compared to continuous feeding group (van Berge Henegouwen et al. 1997). No study has evaluated the effect of EN administration methods on the duration of mechanical ventilation. Post-pyloric tube feeding necessitates continuous or cyclic EN administration due to loss of stomach reservoir capability. For patients being fed into the stomach who have normal gastric function, intermittent or bolus feeding methods can be tolerated. However, intolerance to gastric feeding has been reported in up to 60 % of patients in the ICU (Mentec et al. 2001). Mechanisms of abnormal GI motility in critically ill patients include impaired enteric nerve and smooth muscle function, inflammation (mediated by cytokines and nitric oxide), surgery (gut injury, hypoperfusion), medication (opioids, dopamine), electrolyte disturbance, hyperglycemia, sepsis, and increased intracranial pressure (Ukleja 2010). Clinical signs of abnormal GI motility such as nausea, vomiting, bloating, distention, and diarrhea are usually unavailable before EN initiation. For critically ill patients, it is therefore generally considered acceptable for pump-assisted continuous feeding to be initiated at a rate of ml/h to assess GI tolerance, with volume gradually increased to the target rate; as the patient shows tolerance for EN, continuous or cyclic feeding can be switched to intermittent or bolus feeding. However, converting a patient from continuous or cyclic feeding to intermittent or bolus feeding does not yet have a defined regimen. Application to Other Conditions For medically stable patients receiving gastric feeding with optimal gastric motor function and normal enterokinesis, digestion, and absorption, either continuous, cyclic, intermittent, or bolus feeding methods are acceptable. However, in long-term care hospitals, nursing homes, or home medical care settings, the modalities of EN delivery should take into account practical issues, such as patient mobility, convenience, and cost. For example, in patients who regularly pull or dislodge NG tubes, intermittent or bolus feeding can be safer compared to continuous feeding. In a home medical care setting, gravity-drip feeding is preferred due to low cost and ease of instruction to caregivers or the patient. In terms of continuous or cyclic feeding, both the feeding pumps and pump-specific feeding bags can be quite expensive. Bolus feeding can be particularly beneficial for alert and active patients, as feeding time is shorter than with other methods and the patient is free from any mechanical device, allowing them to live a relatively normal life. Page 14 of 17

15 Table 6 Clinical guidelines for methods of delivering enteral feeding Guideline Recommendation Canadian Critical Care Nutrition Guidelines (2013) National Institute for Health and Care Excellence (NICE) clinical guidelines (2006) There are insufficient data to make a recommendation on enteral feeds given continuously vs. other methods of administration in critically ill patients For people being fed into the stomach, bolus or continuous methods should be considered, taking into account patient preference, convenience and drug administration. For people in intensive care, nasogastric tube feeding should usually be delivered continuously over h daily. If insulin administration is needed it is safe and more practical to administer feeding continuously over 24 h Guidelines and Protocols Methods of enteral feeding delivery remain controversial, and recent guidelines do not recommend any specific method for either critically ill or stable patients (Table 6). For critically ill patients, the Canadian Critical Care Nutrition Guidelines in 2013 (Heyland et al. 2013b) made the following recommendation: There are insufficient data to make a recommendation on enteral feeds given continuously versus other methods of administration in critically ill patients. For adult patients with malnutrition or at risk of malnutrition, the National Institute for Health and Care Excellence (NICE) clinical guidelines (National Collaborating Centre for Acute Care 2006) made the following recommendations: For people being fed into the stomach, bolus or continuous methods should be considered, taking into account patient preference, convenience and drug administration. For people in intensive care, NG tube feeding should usually be delivered continuously over h daily. If insulin administration is needed it is safe and more practical to administer feeding continuously over 24 h. The application of EN feeding protocols has been recommended in clinical practice guidelines to minimize the risks associated with EN during the nutritional management of critically ill patients (Heyland et al. 2013a; McClave et al. 2009). Several studies evaluating the effects of EN feeding protocol in critically ill patients did not apply intermittent or bolus feeding, instead opting for continuous feeding in their protocols (Martin et al. 2004; Barr et al. 2004; Mackenzie et al. 2005). Summary Points Four modalities of delivering enteral tube feeding have been developed: continuous, cyclic, intermittent, and bolus. Many factors are taken into consideration when selecting a delivery method, such as the medical condition of the patient, expected tolerance to tube feeding, location of the feeding tube tip, type of formula used, nutritional requirement, mobility of patient, availability of electric feeding pump, and cost. At present, no evidence suggests that any one feeding method is superior to the others. Page 15 of 17

16 In critical care settings, it is generally acceptable for pump-assisted continuous feeding to be initiated at a rate of ml/h and then gradually increased to the target rate. For medically stable patients, intermittent and bolus feeding methods are preferred due to practical issues, such as patient mobility, convenience, and cost. Recent guidelines have not recommended any specific feeding method for either critically ill or stable patients. References Barr J, Hecht M, Flavin KE, Khorana A, Gould MK. Outcomes in critically ill patients before and after the implementation of an evidence-based nutritional management protocol. Chest. 2004;125: Beau P, Labat J. Continuous vs discontinuous enteral nutrition: compared effects on serum lipids and lipoproteins in humans. JPEN J Parenter Enter Nutr. 1994;18: Bonten MJ, Gaillard CA, van der Hulst R, et al. Intermittent enteral feeding: the influence on respiratory and digestive tract colonization in mechanically ventilated intensive-care-unit patients. Am J Respir Crit Care Med. 1996;154: Brantley SL, Mills ME. Overview of enteral nutrition. In: Mueller CM, editor. The A.S.P.E.N. Nutrition support core curriculum. 2nd ed. Silver Spring: American Society for Parenteral and Enteral Nutrition; p Campbell IT, Morton RP, Cole JA, Raine CH, Shapiro LM, Stell PM. A comparison of the effects of intermittent and continuous nasogastric feeding on the oxygen consumption and nitrogen balance of patients after major head and neck surgery. Am J Clin Nutr. 1983;38: Campbell IT, Morton RP, Macdonald IA, Judd S, Shapiro L, Stell PM. Comparison of the metabolic effects of continuous postoperative enteral feeding and feeding at night only. Am J Clin Nutr. 1990;52: Ciocon JO, Galindo-Ciocon DJ, Tiessen C, Galindo D. Continuous compared with intermittent tube feeding in the elderly. JPEN J Parenter Enter Nutr. 1992;16: Heyland DK, Dhaliwal R, Drover JW, et al. Feeding protocols. In: Canadian critical care nutrition guidelines. 2013a. Accessed 14 Feb Heyland DK, Dhaliwal R, Drover JW, et al. Continuous vs. other methods of administration. In: Canadian critical care nutrition guidelines. 2013b. cpgs2012/6.3.pdf. Accessed 14 Feb Hiebert JM, Brown A, Anderson RG, Halfacre S, Rodeheaver GT, Edlich RF. Comparison of continuous vs intermittent tube feedings in adult burn patients. JPEN J Parenter Enter Nutr. 1981;5:73 5. Kocan MJ, Hickisch SM. A comparison of continuous and intermittent enteral nutrition in NICU patients. J Neurosci Nurs. 1986;18: Lee JS, Auyeung TW. A comparison of two feeding methods in the alleviation of diarrhoea in older tube-fed patients: a randomised controlled trial. Age Ageing. 2003;32: Lee JS, Kwok T, Chui PY, et al. Can continuous pump feeding reduce the incidence of pneumonia in nasogastric tube-fed patients? a randomized controlled trial. Clin Nutr. 2010;29: Mackenzie SL, Zygun DA, Whitmore BL, Doig CJ, Hameed SM. Implementation of a nutrition support protocol increases the proportion of mechanically ventilated patients reaching enteral nutrition targets in the adult intensive care unit. JPEN J Parenter Enter Nutr. 2005;29: Page 16 of 17

17 MacLeod JB, Lefton J, Houghton D, et al. Prospective randomized control trial of intermittent versus continuous gastric feeds for critically ill trauma patients. J Trauma. 2007;63: Martin CM, Doig GS, Heyland DK, et al. Multicentre, cluster-randomized clinical trial of algorithms for critical-care enteral and parenteral therapy (ACCEPT). CMAJ. 2004;20: McClave SA, Martindale RG, Vanek VW, et al. Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). JPEN J Parenter Enter Nutr. 2009;33: Mentec H, Dupont H, Bocchetti M, Cani P, Ponche F, Bleichner G. Upper digestive intolerance during enteral nutrition in critically ill patients: frequency, risk factors, and complications. Crit Care Med. 2001;29: National Collaborating Centre for Acute Care. Enteral tube feeding in hospital and the community. In: Mike Stroud. Nutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition. London: National Institute for Health and Care Excellence; Parrish CR. Enteral feeding: the art and the science. Nutr Clin Pract. 2003;18: Pichard C, Roulet M. Constant rate enteral nutrition in bucco-pharyngeal cancer care. A highly efficient nutritional support system. Clin Otolaryngol Allied Sci. 1984;9: Serpa LF, Kimura M, Faintuch J, Ceconello I. Effects of continuous versus bolus infusion of enteral nutrition in critical patients. Rev Hosp Clin Fac Med Sao Paulo. 2003;58:9 14. Steevens EC, Lipscomb AF, Poole GV, Sacks GS. Comparison of continuous vs intermittent nasogastric enteral feeding in trauma patients: perceptions and practice. Nutr Clin Pract. 2002;17: Tamowicz B, Mikstacki A, Grzymislawski M. The influence of the feeding therapy model on pulmonary complications in patients treated under conditions of intensive therapy. Adv Clin Exp. 2007;16: Ukleja A. Altered GI, motility in critically Ill patients: current understanding of pathophysiology, clinical impact, and diagnostic approach. Nutr Clin Pract. 2010;25: van Berge Henegouwen MI, Akkermans LM, et al. Prospective, randomized trial on the effect of cyclic versus continuous enteral nutrition on postoperative gastric function after pyloruspreserving pancreatoduodenectomy. Ann Surg. 1997;226: Page 17 of 17